JP2000082871A - Printed wiring board and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board having a solder bump forming section in which no defective continuity occurs, because the adhesive property between a refined conductor circuit and a solder resist layer is improved to such a degree that the circuit and layer firmly adhere to each other and are not separated from each other even in the solder bump forming section. SOLUTION: A printed wiring board is provided with a conductor circuit 31 for solder pad, and a solder resist layer 38 which is formed on the circuit 31 and has openings 37 and 36 for providing solder bodies. The conductor circuit 31 has a roughened surface 32 treated with an etchant containing a cupric complex and an organic acid and the solder resist layer 38 is provided on the roughened surface 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board, and more particularly, to a printed wiring board capable of improving the adhesion between a solder pad conductor circuit and a solder resist layer, the solder pad conductor circuit and a solder bump, and the strength of a solder bump. Regarding the board.

[0002]

2. Description of the Related Art In recent years, so-called build-up multilayer wiring boards have been receiving attention due to demands for higher density of multilayer wiring boards. This build-up multilayer wiring board is manufactured, for example, by a method as disclosed in Japanese Patent Publication No. 4-55555.

[0003] An insulating material made of a photosensitive electroless plating adhesive is applied on a core substrate, dried, and then exposed and developed to form an interlayer insulating resin layer having a via hole opening. . Next, after the surface of the interlayer insulating resin layer is roughened by treatment with an oxidizing agent or the like, a plating resist is provided on the roughened surface, electroless plating is performed on the resist non-formed portion, and two layers including via holes are formed. Is formed. By repeating such a process a plurality of times, a multilayered build-up wiring board can be obtained.

[0004] In such a printed wiring board, solder bumps are provided on a surface layer of the printed wiring board.
Connected to chip. At this time, the printed wiring board is provided with a solder resist layer so as to protect the surface solder circuit of the pad and prevent the solder bumps from fusing together.

In the printed wiring board, the surface of the conductor circuit is roughened in order to enhance the adhesion between the solder pad conductor circuit and the solder resist layer. For the roughening treatment of such a conductor circuit, blackening-reducing treatment, etching with sulfuric acid-hydrogen peroxide, copper-nickel-phosphorus needle-like alloy plating, or the like is used.

[0006]

In recent years, a technique using fine wiring as a circuit pattern of a printed wiring board has attracted attention. This is because such fine wiring can increase the density of the conductor circuit.

However, in a miniaturized conductor circuit, the contact area between the conductor circuit and the solder resist layer is significantly reduced, and the adhesion between the conductor circuit and the solder resist layer is reduced. In particular, in the surface layer of the printed wiring board,
When such a conductor circuit is provided in a sparse state, the adhesion between the conductor circuit and the solder resist layer is further reduced.

Further, in such a miniaturized conductor circuit for a solder bump, it is difficult to maintain the strength of the solder bump, and the solder bump may fall off.

According to the present invention, the adhesion between the miniaturized conductor circuit and the solder resist layer is improved, and the conductor circuit and the solder resist layer are firmly adhered to each other even in the solder bump formation portion, and the solder bump is not separated. An object of the present invention is to obtain a printed wiring board that does not cause poor conduction in a formed portion.

Another object of the present invention is to provide a printed wiring board capable of maintaining the strength of the contact portion between the solder bump conductor circuit and the solder bump in a high state and preventing the solder bump from falling off. Aim.

[0011]

According to the present invention, there is provided a conductor circuit for a solder pad and a solder resist layer on the conductor circuit for a solder pad, and an opening for providing a solder body is formed in the solder resist layer. In the printed wiring board being formed, the solder pad conductor circuit has a roughened surface that has been treated with an etching solution containing a cupric complex and an organic acid, and the solder resist layer has a rough surface. The present invention relates to a printed wiring board provided on a surface to be printed.

The present invention also provides a printed wiring board comprising a conductor circuit and a solder resist layer on the conductor circuit, wherein an opening for providing a solder body is formed in the solder resist layer. The conductor circuit has a roughened surface, the roughened surface has a plurality of anchors, dents, and ridges, and the anchors, the dents, and the ridges are dispersedly formed. The adjacent anchor-shaped portions are connected by the ridge line, and the recessed portion is surrounded by the anchor-shaped portion and the ridge line, and the solder resist layer is provided on the roughened surface. And a printed wiring board.

Further, the present invention comprises a solder pad conductor circuit and a solder resist layer on the solder pad conductor circuit, and an opening for providing a solder body is formed in the solder resist layer. In the printed wiring board, the solder pad conductor circuit has a roughened surface that is treated with an etchant containing a cupric complex and an organic acid, and the roughened surface includes titanium, zinc,
Iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and coated with a metal layer of at least one metal selected from the group consisting of noble metals,
The present invention relates to a printed wiring board in which the solder resist layer is provided on the roughened surface and a method for manufacturing the same.

Further, the present invention comprises a solder pad conductor circuit and a solder resist layer on the solder pad conductor circuit, and an opening for providing a solder body is formed in the solder resist layer. In the printed wiring board, the solder pad conductive circuit has a roughened surface, the roughened surface has a plurality of anchor-shaped portions, dents, and ridges, and the anchor-shaped portion and the dents The ridgeline is formed in a dispersed manner, and the adjacent anchor-shaped portions are connected by the ridgeline, and the dent portion is surrounded by the anchor-shaped portion and the ridgeline, and the roughened surface is Titanium, zinc, iron, indium, thallium, cobalt, nickel,
According to a printed wiring board, which is covered with a metal layer of at least one metal selected from the group consisting of tin, lead, bismuth and a noble metal, and wherein the solder resist layer is provided on the roughened surface. is there.

The present inventors have studied various methods for roughening the surface of a conductive circuit in order to improve the adhesion between the surface layer of a multilayer printed wiring board and a solder resist layer. In particular, the inventor
In response to a demand to increase the adhesion between a conductor circuit formed by fine wiring of 50 μm or less and a solder resist layer and the strength of a solder bump, blackening-reduction treatment, etching with sulfuric acid-hydrogen peroxide, and copper-nickel -A treatment method such as phosphor needle alloy plating was studied.

However, it has been found that a blackening-reducing treatment or the like is not suitable as a roughening treatment for fine wiring. In the case of blackening-reducing treatment or etching treatment of sulfuric acid-hydrogen peroxide, 50 μm
When the wiring density is reduced by using fine wiring of not more than m, the ground area between the conductor circuit and the solder resist layer is reduced due to the convex portion formed on the roughened surface, and the adhesion of the solder resist layer cannot be improved. I found that. In particular, it was found that the film was peeled off at a portion where the wiring density was low under the heat cycle condition. In addition, the metal in the solder pad was peeled off or cracked, causing the solder bump to fall off.

The formation of a roughened layer by copper-nickel-phosphorus needle-like alloy plating is excellent in adhesion between a conductor circuit and a solder resist, and fine wiring of 50 μm or less, particularly,
It has been found that even a sparse portion made of such wiring shows a sufficient adhesion. However, since such a roughened layer is formed by plating, when the density of fine wiring is increased, it is found that the precipitated needle-shaped alloy extends on the interlayer insulating layer and connects the conductor circuits to each other, causing a short circuit. Was.

In the formation of a roughened layer using a copper-nickel-phosphorus needle-like alloy, it is necessary to strictly control and control the plating solution in order to prevent abnormal precipitation due to elongation of the needle-like alloy. In addition, the solder resist layer formed from the resin is removed through exposure and development in the solder bump forming portion.

At this time, in the roughened layer made of the copper-nickel-phosphorus needle-like alloy, since the needle-like protrusions are densely formed, the space between the protrusions is narrow. In some cases, the oxidant solution for removing the resin does not flow, and the resin remains between the protrusions, leaving an organic residue of the solder resist resin at the bottom of the opening. This residue may cause poor conduction between the conductor circuit in the opening and the metal under the bump.
In addition, the residue may cause the formation of a noble metal layer in the solder pad to be unformed or defective, and the strength between the solder pad and the conductor circuit may be reduced.

Under such knowledge, the present inventor has intensively studied other roughening treatments. As a result, the roughened surface formed by treating the surface of the conductor circuit with an etching solution containing a cupric complex and an organic acid may have an adhesive property with a solder resist resin or a metal with an under bump. They have found that they have excellent adhesion and are extremely suitable for forming solder bumps, and have completed the present invention.

[0021] The printed wiring board of the present invention has a roughened surface having a predetermined rough surface shape on a conductive circuit, such as formed by the etching solution, and a solder resist is formed through the roughened surface. A layer is provided. Such a roughened surface can be formed even on a conductive circuit formed of fine wiring having a size of 50 μm or less and having a high wiring density without causing conduction failure such as copper-nickel-phosphorus needle-like alloy plating.

Further, such a roughened surface has excellent adhesion to the solder resist layer, and when the solder resist layer is removed at the solder bump forming portion, the contact area between the conductor circuit and the solder resist layer is reduced. Even with a printed wiring board made of fine wiring and having a low wiring density, sufficient adhesion between the conductor circuit and the solder resist layer can be ensured.

Further, when the solder resist layer is removed to provide an opening for forming a solder bump, the roughened surface has little resin residue on the roughened surface and has excellent adhesion to the metal under the bump. In addition, conduction failure does not occur in the solder bump forming portion.

On the other hand, the present inventor has studied in more detail the roughened surface of the conductor circuit for a solder pad in order to increase the strength of the solder bump.

As a result, the present inventor has found that such a roughened surface is
It has been found that it is significantly deteriorated due to oxidation, corrosion and the like.
According to the study of the present inventors, it has been found that when such a roughened surface is deteriorated, the strength of the uneven portion on the surface is significantly reduced, and the uneven portion is dissolved by a solvent such as an acid or an alkali. Such deterioration of the roughened surface markedly weakened the adhesion strength between the solder resist layer and the roughened surface and between the roughened surface and the metal under the bump, and was peeled off.

Based on this finding, the present inventor attempted to increase the adhesion strength between the solder resist layer and the roughened surface or between the roughened surface and the metal under the bump to prevent peeling, and to prevent the peeling. The research on the surface processing was studied diligently.

As a result, the present inventor has proposed that such a roughened surface
Titanium, zinc, iron, indium, thallium, cobalt,
A printed wiring board manufactured by coating a metal layer of at least one metal selected from the group consisting of nickel, tin, lead, bismuth and a noble metal, and providing a solder resist layer on the roughened surface, The inventors have found that the strength of the present invention is significantly increased, and have completed the present invention.

In the present invention, such a metal layer prevents oxidation, corrosion, and the like of the roughened surface, and prevents surface deterioration of the roughened surface. Further, in the present invention, such a metal layer protects the uneven portion of the roughened surface from a solvent such as an acid or an alkali, and when the roughened surface is immersed in such a solvent, the uneven portion of the roughened surface is dissolved. Prevent it from getting lost.

According to the present invention, the metal layer prevents the strength of the roughened surface from decreasing, and the roughened surface covered with the metal layer retains its shape and strength. It is possible to eliminate the delamination of the layer and the unformed and defective formation of the metal layer in the solder pad.

The roughened surface coated with such a metal layer has less surface deterioration of the roughened surface than the roughened surface not coated with the metal layer and having a solder resist layer and a solder bump, and thus has a roughened surface. Can be made uniform, and the dissolution of the roughened surface due to oxidation or chemicals can be prevented.

If a printed wiring board having such a roughened surface is used, the adhesion strength between the solder pad conductor circuit and the solder bump is significantly improved. For example, solder bumps improve ball shear strength by at least 10%. Further, even when a reliability test is performed, there is no peeling of the solder resist layer, no peeling of the metal layer, no crack, and no dropping of the solder bump occurs.

In the printed wiring board of the present invention, the roughened surface of the conductor circuit for a solder pad is covered with a metal layer, so that the printed wiring board has a shape and excellent adhesion to the solder resist layer and to the metal under the bump. Since the strength is maintained, the strength of the solder bump is significantly increased, and the solder bump can be prevented from falling off.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the drawings. When the conductor circuit for a solder pad is treated with the etching solution according to the present invention, the surface thereof becomes a roughened surface having an anchor-shaped portion as shown in FIGS. FIG. 1 is a drawing substitute photograph of a roughened surface according to an example of the present invention. In this photograph, the roughened surface is photographed obliquely under an electron microscope. FIG. 2 is a drawing substitute photograph of a roughened surface of another example according to the present invention. This photograph was taken in the same manner as the photograph of FIG.
The magnification is increased. FIG. 3 is a drawing substitute photograph of a roughened surface of still another example according to the present invention. This photograph was taken at the same magnification as in FIG. 2 and the roughened surface was photographed from directly above under an electron microscope.

In the printed wiring board of the present invention, a solder resist layer is provided on the conductor circuit for the solder pad via the roughened surface of the conductor circuit for the solder pad as shown in the electron micrograph.

4 to 8 are schematic diagrams of such a roughened surface. 4 is a plan view, FIG. 5 is a vertical cross-sectional view taken along line AA of FIG. 4, FIG. 6 is a vertical cross-sectional view cut between an anchor-shaped portion and a concave portion, and FIG. Longitudinal sectional view showing a ridge line between the shaped parts,
FIG. 8 is a longitudinal sectional view cut between a ridge line and a depression.

As shown in FIGS. 4 and 5, the roughened surface according to the present invention has a plurality of anchors 1, a plurality of depressions 2, and a plurality of ridges 3. The depression 2 and the ridge 3 are dispersed. A recess 2 is formed between the anchor 1 and the adjacent anchor 1 as shown in FIG. In addition, the anchor-shaped portion 1 and the adjacent anchor-shaped portion 1 are connected to each other by a ridge line 3 as shown in FIG. Recess 2
Is surrounded by the anchor 1 and the ridge 3 as shown in FIGS.

For comparison, FIG. 32 is a drawing substitute photograph of a roughened layer made of a conventional needle-shaped alloy formed by plating. In the roughened layer shown in the electron micrograph, the acicular alloys overlap each other, and a space is formed between the acicular alloys.
In such a needle-shaped alloy structure made of Cu-Ni-P, since the needle-shaped protrusions are densely packed, the space between the protrusions is narrow, and the oxidizing agent solution for removing the developer or the resin residue does not flow,
Resin remains between the protrusions, causing resin to remain.

On the other hand, the rough surface shape according to the present invention has an anchor portion at the highest portion, and a depression portion is formed at the lowest portion around the anchor portion, and the anchor portion and the adjacent portion thereof are formed. Are connected to each other by a ridgeline lower than the anchor-shaped portions and higher than the recessed portions, and have a complicated uneven shape.
In such a roughened surface having a complicated uneven shape, the anchor-shaped portion bites into the solder resist layer, and the conductor circuit and the solder resist layer are firmly adhered to each other. Even in the state of
No peeling occurs between the conductor circuit and the solder resist layer. In addition, such a roughened surface has an excellent affinity with the plating solution, and the plating penetrates into the recessed portion of the roughened surface and wraps around the anchor-shaped portion of the roughened surface. In addition, the adhesiveness between the conductor circuit and the solder bump is not reduced.

On the roughened surface, the anchor portions are not dense. The ridge connecting the anchor portions has a shape that does not obstruct the flow of the resin. For this reason, on the roughened surface, the developer or the oxidizing agent solution for removing the resin residue easily flows between the recessed portions and the anchor-shaped portions, and the solder resist resin does not easily accumulate. Therefore, the roughened surface according to the present invention has no resin residue after the development processing, and is excellent in adhesion to the metal under the bump.

As described above, the roughened surface according to the present invention can maintain the adhesion between the conductor circuit and the solder resist layer and the adhesion between the conductor circuit and the metal under the bump while maintaining the resin residue after the development processing. Has the best shape to prevent.

The roughened surface according to the present invention can be formed, for example, by dropping metal crystal particles on the surface of a conductor circuit with an etching solution containing a cupric complex and an organic acid. On such a roughened surface, a depression (recess) is formed at a portion where the metal crystal particles have largely dropped. Such a depression can be formed in a shape as if a substantially polyhedral substance derived from the metal crystal particles is cut off. In the present invention, the substantially polyhedral shape refers to a polyhedron such as a trihedron, a tetrahedron, a pentahedron, a hexahedron, or a polyhedron obtained by combining two or more of these polyhedrons. Such depressions can prevent resin residue after the development processing.

Further, the anchor portion of the roughened surface can be formed by dropping metal crystal particles around the anchor portion. The anchor-shaped portion formed in this manner is constituted by a square convex portion, is surrounded by the concave portion, and does not overlap with each other. The roughened surface having such a complicated uneven shape can prevent the resin residue after the development processing while maintaining the adhesion to the solder resist resin and the metal under the bump.

Further, a ridge line can be formed on the roughened surface by dropping of adjacent metal crystal particles. This ridge connects the anchor-shaped part and the adjacent anchor-shaped part at a position lower than the height of the anchor-shaped part. The ridge is formed in a branched state by dropping three or more adjacent metal crystal particles. In addition, the ridge line can be formed in a sharp state by the neighboring metal crystal particles falling in a substantially polyhedral shape and falling off. Such ridges can be formed such that the anchors are dispersed and the anchors are surrounded by the depressions and the ridges. Such a roughened surface has a more complicated uneven shape, and can enlarge the contact surface with the resin and the metal under the bump, thereby improving the adhesion and preventing the resin from remaining.

The roughened surface preferably has a maximum roughness (Rmax) of 0.5 to 10 μm. If it is less than 0.5 μm, the adhesion to the solder resist layer and the adhesion to the metal under the bump will be significantly reduced, and if it exceeds 10 μm, resin residue will occur after the development process, and problems such as disconnection will easily occur.

The roughened surface is 25 μm^TwoHit
An average of 2 to 100 anchors and an average of 2 to 100 depressions
It is preferable to have a part. 25 μm^TwoHit, average
2 to 100 anchors are roughened surface and solder resist layer
Adhesion between the roughened surface and the metal under the bump
While preventing resin residue after the development process. ^Two
The average of 2 to 100 depressions per contact prevents dense anchor-shaped parts
To suppress the occurrence of resin residue after the development process, and
Adhesion between the roughened surface and the solder resist layer,
Adhesion with the metal under the pump can be maintained.

[0046] ridge according to the present invention, 25μm ² per,
It is desirable to form an average of 3 to 3000 lines. The number of ridges in this range complicates the shape of the roughened surface, expands the contact surface with the solder resist layer and the metal under the bump, and can improve the adhesiveness with the solder resist layer, etc. This is because the remainder is easily removed.

The number of anchors, dents, and ridges was determined using a 5000 × electron microscope photograph as shown in FIGS.
A region of 25 μm ² was arbitrarily selected and measured, and the average value was adopted.

In the present invention, a metal layer can be coated on such a roughened surface. 9 to 12 are cross-sectional views of another example of a roughened surface according to the present invention. 9 to 12, FIG.
The roughened surfaces as indicated by Nos. To 8 are each covered with a metal layer 51.

The metal layer 51 as shown in FIGS. 9 to 12 is made of a metal which is hardly oxidized or corroded, or has a good adhesion with a solder resist resin or a metal under a bump even if the metal itself is oxidized or corroded. It is made of metal that does not impair.

The metal layer is coated while maintaining the shape of the roughened surface while preventing the formation of an oxide film or a corrosive film on the roughened surface. Does not impair the adhesion to the surface.

Such a metal layer causes a decrease in the adhesion strength between the roughened surface and the solder resist layer and a decrease in the adhesion strength between the roughened surface and the metal under the bump due to peeling of the oxide film or corrosion. Can be prevented.

The metal layer can also increase the hardness of the metal constituting the roughened surface, so that the metal is not destroyed on the roughened surface, and the roughened surface and the solder resist layer, and the roughened surface and the bump Separation from the lower metal is further prevented.

The printed wiring board of the present invention has a metal layer having a roughened surface, an oxide layer or a corroded layer is hardly formed on the roughened surface. Adhesion between the resin and the metal under the bump is maintained, and even when heated, there is no separation between the roughened surface and the solder resist layer or between the roughened surface and the metal under the bump.

The metal layer comprises at least one selected from the group consisting of titanium, zinc, iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and a noble metal.
It consists of a kind of metal.

Such metals are relatively hard to oxidize and corrode,
Alternatively, even if the metal itself is oxidized or corroded, the adhesion between the solder resist resin and the metal under the bump is not reduced.

Further, such a metal is a metal or a noble metal having an ionization tendency greater than copper and equal to or less than titanium,
If you cover the roughened surface with a layer of these metals or precious metals,
Dissolution of the conductor circuit due to a local electrode reaction when roughening the solder resist layer can be prevented.

Metals which are relatively hard to oxidize or corrode include
Non-oxidizing metals such as nickel, tin, cobalt, and noble metals are exemplified. As the noble metal, at least one selected from gold, silver, platinum, and palladium is desirable.

Metals such as titanium, zinc, iron, indium, thallium, lead, bismuth and the like which do not decrease the adhesion between the metal layer and the solder resist resin even if the metal itself oxidizes or corrodes. Can be mentioned.

As described above, according to the present invention, on the roughened surface, at least one metal selected from the group consisting of titanium, zinc, iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and noble metals is used. By coating the metal layer, it has the optimal shape to prevent resin residue after development processing, while maintaining the adhesion between the solder bump conductor circuit and the solder resist layer, and the solder bump conductor circuit and the under bump. Adhesion with metal and strength of solder bumps can be improved.

In order to coat the metal layer on the roughened surface, a method such as plating (a method selected from electrolytic plating, electroless plating and displacement plating), vapor deposition, electrodeposition, and sputtering may be used. it can.

The thickness of the metal layer is 0.01 to 1 μm
Is good. In particular, a thickness of 0.03 to 0.5 μm is preferable. This is because the metal layer having such a thickness can prevent oxidation and corrosion of the copper conductor while maintaining the shape of the irregularities on the roughened surface. 0.
When the thickness is less than 01 μm, the roughened surface cannot be completely covered. When the thickness is more than 1 μm, the metal to be coated enters between the roughened surfaces, and the roughness of the roughened surface may be offset. The adhesiveness between the surface and the solder resist layer and the adhesiveness between the roughened surface and the metal under the bump may be reduced.

A method for forming a roughened surface according to the present invention will be described. Such a roughened surface can be formed by treating a conductor circuit serving as a solder pad with an etchant containing a cupric complex and an organic acid. Such an etchant can dissolve the copper conductor circuit under oxygen-existing conditions such as spraying and bubbling. The reaction is presumed to proceed as follows.

[0063]

Embedded image [In the formula, A represents a complexing agent (acting as a chelating agent), and n represents a coordination number. ]

As shown in the chemical formula 1, the generated cuprous complex dissolves under the action of an acid and combines with oxygen to form a cupric complex, which again contributes to copper oxidation.

The cupric complex used in the present invention is preferably an azole cupric complex. This type of cupric complex acts as an oxidizing agent for oxidizing metallic copper and the like. As the azoles, diazole, triazole and tetrazole are preferable.
Among them, imidazole, 2-methylimidazole, 2-
Ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole and the like are preferred. The addition amount of the cupric complex of azoles is preferably 1 to 15% by weight. This is because they are excellent in solubility and stability.

The organic acid is blended with the cupric complex to dissolve the copper oxide. When using a cupric complex of azoles, the organic acid is formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, crotonic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, At least one selected from the group consisting of maleic acid, benzoic acid, glycolic acid, lactic acid, malic acid, and sulfamic acid is preferred. The content of the organic acid is preferably 0.1 to 30% by weight. This is for maintaining the solubility of the oxidized copper and ensuring the solubility stability.

To the etching solution according to the present invention, halogen ions such as fluorine ions, chlorine ions and bromine ions may be added to assist in dissolving copper and oxidizing azoles. Such halogen ions can be supplied as hydrochloric acid, sodium chloride and the like. The addition amount of halogen ions is preferably 0.01 to 20% by weight. This is because the adhesiveness between the formed roughened surface and the solder resist layer is excellent.

The etching solution according to the present invention can be prepared by dissolving a cupric complex of azoles and an organic acid (optionally a halogen ion) in water. Also,
A commercially available etchant, for example, a trade name “Mech Etch Bond” manufactured by Mec Corporation can be used.

The average amount of etching with such an etching solution is preferably 0.1 to 10 μm. When the thickness is less than 0.1 μm, the adhesion between the roughened surface and the solder resist layer is reduced. When the thickness exceeds 10 μm, resin residue is apt to be generated.

In the present invention, a metal layer can be coated on the roughened surface thus formed. The metal layer is made of at least one metal selected from the group consisting of titanium, zinc, iron, indium, thallium, cobalt, nickel, tin, lead, bismuth, and noble metals. The coating of the metal layer can be performed by any of plating, vapor deposition, electrodeposition, and sputtering. In terms of the uniformity of the formed film, it is preferable to perform plating.

Further, in the present invention, in order to form such a metal layer uniformly, after forming a roughened surface, the roughened surface can be heat-treated before forming the metal layer. . The heat treatment evaporates the etching solution and its residual components, and the surface state of the roughened surface becomes uniform, so that the metal layer is easily formed.

The temperature of the heat treatment can be set in various ranges depending on the shape and thickness of the roughened surface, the metal component and the thickness of the conductor circuit for solder pads, and the like. In particular, 50-250 ° C
It is better within the range. When the temperature is lower than 50 ° C., the effect of the heat treatment is not observed. When the temperature is higher than 250 ° C., the roughened surface is oxidized, and the formed metal layer becomes non-uniform.

In the present invention, a solder resist layer is formed on a roughened surface having a predetermined shape formed as described above.
The thickness of the solder resist layer is preferably 5 to 40 μm. If it is too thin, the solder resist layer will not function as a solder dam, and if it is too thick, it will be difficult to form openings for solder bumps, and it will come into contact with the solder body and cause cracks in the solder body It is.

The solder resist layer can be formed from various resins. For example, it can be formed by curing a bisphenol A-type epoxy resin or its acrylate, or a novolak-type epoxy resin or its acrylate with an amine-based curing agent or an imidazole curing agent.

In particular, when an opening is provided in the solder resist layer to form a solder bump, it is preferable to cure a novolak epoxy resin or its acrylate with an imidazole curing agent. The solder resist layer made of such a resin has an advantage that migration of lead (a phenomenon in which lead ions diffuse in the solder resist layer) is small.

In the case of a resin obtained by curing an acrylate of a novolak type epoxy resin with an imidazole curing agent,
It has excellent heat resistance and alkali resistance, does not deteriorate even at the temperature at which the solder melts (around 200 ° C), and does not decompose in strongly basic plating solutions such as nickel plating and gold plating. Examples of the acrylate of the novolak epoxy resin include an epoxy resin obtained by reacting glycidyl ether of phenol novolak or cresol novolak with acrylic acid, methacrylic acid, or the like.

However, since the solder resist layer formed of the acrylate of the novolak type epoxy resin is formed of a resin having a rigid skeleton, the solder resist layer is easily peeled off from the conductor circuit. The roughened surface according to the present invention is advantageous because such peeling can be prevented.

The imidazole curing agent is desirably liquid at 25 ° C. This is because if it is liquid, it is easy to mix uniformly. Examples of such curing agents include 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 resin and the curing agent are preferably dissolved in a glycol ether-based solvent to form a solder resist composition. When a solder resist layer is formed from such a composition, free oxygen is not generated and the copper pad surface is not oxidized. It is also less harmful to the human body.

As the glycol ether solvent, the following general formula: CH ₃ O— (CH ₂ CH ₂ O) _n —CH ₃ (n = 1 to 1)
5) A solvent represented by the following formula can be used.

Particularly preferably, at least one selected from the group consisting of diethylene glycol dimethyl ether (DMDG) and triethylene glycol dimethyl ether (DMTG) is used. These solvents are 30-50 ° C
With a certain degree of heating, a reaction initiator such as benzophenone or Michler's ketone can be completely dissolved. The amount of the solvent is 10 to 40% by weight of the solder resist composition.
Is good.

The addition amount of the imidazole curing agent is preferably 1 to 10% by weight based on the total solid content of the solder resist composition. If the amount is within this range, uniform mixing is easy.

In addition to the above-mentioned solder resist composition, various antifoaming agents and leveling agents, thermosetting resins for improving heat resistance and base resistance and imparting flexibility, and improving resolution can be used. For example, a photosensitive monomer or the like can be added.

As the leveling agent, one composed of an acrylic ester polymer is preferred. The initiator is preferably Irgacure I907 manufactured by Ciba-Geigy, and the photosensitizer is DETX-S manufactured by Nippon Kayaku.

As the thermosetting resin, a bisphenol type epoxy resin can be used. This bisphenol type epoxy resin includes a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, and when importance is attached to base resistance, the former is required to reduce viscosity (when importance is attached to coating properties). The latter is better.

As the photosensitive monomer, a polyacrylic monomer can be used. This is because the polyvalent acrylic monomer can improve the resolution. For example, Nippon Kayaku's DPE-6A and Kyoeisha Chemical's R-6
A polyvalent acrylic monomer such as 04 can be used.

Dyes and pigments 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 such a dye.

Further, the composition for a solder resist is preferably 0.5 to 10 Pa · s at 25 ° C., more preferably,
It preferably has a viscosity of 1 to 10 Pa · s. This is because application with a roll coater is easy. Such a composition can form an opening by exposure and development after forming a solder resist layer.

Next, a method for manufacturing the printed wiring board of the present invention will be described. The following method is mainly based on the semi-additive method, but may use the full-additive method.

In the present invention, a wiring board having a conductor circuit to be a solder pad formed on the surface of the board is manufactured. As the substrate, a resin insulating substrate such as a glass epoxy substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a ceramic substrate, a metal substrate, or the like can be used.

The wiring board may be a multilayer printed wiring board having a plurality of conductor circuits formed therein. To form such a multi-layer conductive circuit, an adhesive layer made of an electroless plating adhesive is formed as an interlayer insulating resin layer on a lower conductive circuit provided on a substrate, and the surface of the adhesive layer is formed. After roughening the surface to a roughened surface, applying a thin electroless plating to the entire roughened surface, forming a plating resist, applying a thick electrolytic plating to a portion where no plating resist is formed, and then removing the plating resist Then, an etching process is performed to form a two-layer conductor circuit including an electrolytic plating film and an electroless plating film. The conductor circuit preferably has a copper pattern.

The adhesive for electroless plating is obtained by dispersing cured heat-resistant resin particles soluble in an acid or an oxidizing agent in an uncured heat-resistant resin hardly soluble in an acid or an oxidizing agent. Optimal. This is because such heat-resistant resin particles are dissolved and removed by treatment with an acid or an oxidizing agent to form a roughened surface composed of an octopus pot-shaped anchor on the surface. The adhesive for electroless plating may be composed of two layers having different compositions.

The cured heat-resistant resin particles soluble in acids and oxidizing agents include (1) heat-resistant resin powder having an average particle diameter of 10 μm or less, and (2) heat-resistant resin powder having an average particle diameter of 2 μm or less. (3) a mixture of a heat-resistant resin powder having an average particle size of 2 to 10 μm and a heat-resistant resin powder having an average particle size of less than 2 μm, and (4) a heat-resistant resin having an average particle size of 2 to 10 μm. Particles having at least one of a heat-resistant resin powder having an average particle diameter of 2 μm or less and an inorganic powder adhered to the surface of the conductive resin powder,
(5) a mixture of a heat-resistant resin powder having an average particle size of 0.1 to 0.8 μm and a heat-resistant resin powder having an average particle size of more than 0.8 μm and less than 2 μm, (6) an average particle size of 0.1 It is desirable to use at least one kind of particles selected from the group consisting of heat-resistant resin powders having a size of from 1.0 μm to 1.0 μm. This is because they form a more complex anchor. The roughened surface obtained by these particles has a maximum roughness (Rma) of 0.1 to 20 μm.
x).

The mixing ratio of the heat-resistant resin particles is 5 to 50% by weight based on the solid content of the matrix made of the heat-resistant resin.
Desirably, the content is 10 to 40% by weight. In addition, such heat-resistant resin particles include amino resins (melamine resins, urea resins,
Guanamine resin), epoxy resin and the like.

The uncured heat-resistant resin hardly soluble in an acid or an oxidizing agent is a resin composite of a thermosetting resin and a thermoplastic resin or a resin composite of a photosensitive resin and a thermoplastic resin. Is desirable. This is because the former has high heat resistance, and the latter can form an opening for a via hole by photolithography.

As the thermosetting resin, an epoxy resin, a phenol resin, a polyimide resin or the like can be used. In the case of photosensitization, a thermosetting group is subjected to an acrylate reaction with methacrylic acid, acrylic acid, or the like. In particular, an acrylate of an epoxy resin is most suitable. As the epoxy resin, a novolak type epoxy resin such as a phenol novolak type or a cresol novolak type, an alicyclic epoxy resin modified with dicyclopentadiene, or the like can be used.

As the thermoplastic resin, polyether sulfone (PES), polysulfone (PSF), polyphenylene sulfone (PPS), polyphenylene sulfide (PPES), polyphenyl ether (PP
E), polyetherimide (PI) and the like can be used.

The mixing ratio between the thermosetting resin (photosensitive resin) and the thermoplastic resin is preferably such that thermosetting resin (photosensitive resin) / thermoplastic resin = 95/5 to 50/50. This is because high physical properties can be obtained without impairing heat resistance.

Next, the adhesive for electroless plating is cured to form an interlayer insulating resin layer, and the interlayer resin resin layer can be provided with an opening for forming a via hole.

The opening for forming the via hole is formed by using laser light or oxygen plasma when the resin matrix of the adhesive for electroless plating is a thermosetting resin, and is exposed when the resin matrix is a photosensitive resin. Perforate in development processing. In the exposure and development processing, a photomask (preferably a glass substrate) on which a circular pattern is drawn for forming a via hole is placed so that the circular pattern side is in close contact with the photosensitive interlayer resin insulating layer. Exposure and development processing.

Next, the surface of the interlayer resin insulating layer (adhesive layer for electroless plating) provided with openings for forming via holes is roughened. In particular, the surface of the adhesive layer is roughened by dissolving and removing the heat-resistant resin particles present on the surface of the adhesive layer for electroless plating with an acid or an oxidizing agent. At this time, a roughened surface is formed on the interlayer resin insulating layer. At this time, the depth of the depression formed on the roughened surface is preferably about 1 to 5 μm.

For the treatment with an acid, an inorganic acid such as phosphoric acid, hydrochloric acid or sulfuric acid, or an organic acid such as formic acid or acetic acid can be used. In particular, it is desirable to use an organic acid. This is because it is difficult to corrode the metal conductor layer exposed from the via hole when the roughening treatment is performed. For the treatment with the oxidizing agent, it is desirable to use chromic acid or permanganate (such as potassium permanganate).

The roughened surface preferably has a maximum roughness (Rmax) of 0.1 to 20 μm. If the thickness is too large, the layer itself is likely to be damaged and peeled off, and if it is too thin, the adhesion is reduced. In particular, in the semi-additive method, 0.1 to
5 μm is preferred. This is because the electroless plating film is removed while maintaining the adhesion.

Next, a catalyst nucleus is provided on the roughened interlayer resin insulating layer, and a thin electroless plating film is formed on the entire surface.
This electroless plating film is preferably formed by electroless copper plating, and has a thickness of 1 to 5 μm, more preferably 2 to 3 μm.
In addition, as the electroless copper plating solution, a solution having a liquid composition adopted by a usual method can be used. For example, copper sulfate:
10 g / L, EDTA: 50 g / L, sodium hydroxide: 8
A liquid composition consisting of g / L and 37% formaldehyde: 10 mL is preferred.

Next, a photosensitive resin film (dry film) is laminated on the electroless plating film thus formed, and a photomask (glass substrate) on which a plating resist pattern is drawn on the photosensitive resin film. Are placed in close contact with each other, exposed, and developed to form a non-conductive portion on which a plating resist pattern is provided.

Next, an electrolytic plating film is formed on a portion other than the non-conductor portion on the electroless copper plating film to provide a conductor circuit and a conductor portion serving as a via hole. As the electrolytic plating, it is desirable to use electrolytic copper plating, and its thickness is preferably 5 to 20 μm.

Next, after removing the plating resist in the non-conductive circuit portion, the substrate is further treated with a mixed solution of sulfuric acid and hydrogen peroxide or an etching solution such as sodium persulfate, ammonium persulfate, ferric chloride, cupric chloride and the like. Then, the electroless plating film is removed to obtain independent conductor circuits and via holes each having two layers of the electroless plating film and the electrolytic plating film. The palladium catalyst nuclei on the roughened surface exposed to the non-conductive portion are dissolved and removed with a mixed solution of chromic acid, sulfuric acid and hydrogen peroxide or the like.

Next, the roughened surface according to the present invention is formed on the conductor circuit serving as the surface solder pad. Such a roughened surface is formed by spraying an etching solution comprising an aqueous solution of the above-mentioned cupric complex of an azole and an organic acid on the surface of the conductor circuit, or immersing the conductor circuit in the etching solution and bubbling. Can be. Note that the conductor circuit is preferably an electroless plating film or an electrolytic plating film. This is because a roughened surface is hardly formed in a conductor circuit obtained by etching a thick copper foil.

The roughened surface thus formed can be further processed by an etching process, a polishing process, an oxidation process, an oxidation-reduction process, or the like, and can be covered with a plating film.

The roughened surface is made of titanium, zinc,
It can be covered with a metal layer made of at least one metal selected from the group consisting of iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and noble metals. The coating method can be performed by plating (a method selected from electrolytic plating, electroless plating, and displacement plating), vapor deposition, electrodeposition, sputtering, and the like.

The solder resist layer as described above can be formed on the conductor circuit having the roughened surface subjected to the above processing.

[0112]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, the present invention will be described based on embodiments and comparative examples. Example 1 Raw material composition for preparing an adhesive for electroless plating (adhesion for upper layer)
Agent) [Resin Composition A] 80 wt% of 25% acrylate of cresol novolak type epoxy resin (Nippon Kayaku, molecular weight 2500)
35% by weight of a resin solution dissolved in DMDG at a concentration of 3.15% and a photosensitive monomer (Toa Gosei Co., Aronix M315) 3.15
Parts by weight, 0.5 parts by weight of an antifoaming agent (manufactured by San Nopco, S-65)
3.6 parts by weight of NMP were obtained by stirring and mixing.

[Resin Composition B] 12 parts by weight of polyether sulfone (PES), epoxy resin particles (manufactured by Sanyo Chemical Co., Ltd.)
After mixing 7.2 parts by weight of a polymer pole having an average particle size of 1.0 μm and 3.09 parts by weight of an average particle size of 0.5 μm, 30 parts by weight of NMP was further added, and the mixture was stirred and mixed with a bead mill.

[Curing Agent Composition C] 2 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), 2 parts by weight of a photoinitiator (Irgacure I-907, manufactured by Ciba Geigy), and a photosensitizer (Nippon Kayaku) 0.2 parts by weight of DETX-S) and 1.5 parts by weight of NMP.

Raw material composition for preparing interlayer resin insulating agent (lower layer
Adhesive for Resin ) [Resin Composition D] 80% of 25% acrylate of cresol novolac type epoxy resin (Nippon Kayaku, molecular weight 2500)
% Of a resin solution dissolved in DMDG at a concentration of 35%, 4 parts by weight of a photosensitive monomer (Alonix M315, manufactured by Toagosei Co., Ltd.), 0.5 parts by weight of an antifoaming agent (S-65, manufactured by San Nopco), N
3.6 parts by weight of MP were obtained by stirring and mixing.

[Resin Composition E] 12 parts by weight of polyether sulfone (PES) and epoxy resin particles (manufactured by Sanyo Chemical Industries, Ltd.)
After mixing with 14.49 parts by weight of a polymer pole having an average particle size of 0.5 μm, 30 parts by weight of NMP was further added, and the mixture was stirred and mixed with a bead mill.

[Curing Agent Composition F] 2 parts by weight of imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals), 2 parts by weight of photoinitiator (Irgacure I-907, manufactured by Ciba Geigy), photosensitizer (Nippon Kayaku) 0.2 parts by weight of DETX-S) and 1.5 parts by weight of NMP.

Raw material composition for preparing resin filler [Resin composition G] 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell, molecular weight 310, YL983U), average particle having a surface coated with a silane coupling agent 1.6 μm diameter SiO ₂ spherical particles (manufactured by Admatech, CRS 11
01-CE, where the maximum particle size is 170 parts by weight of the inner layer copper pattern described below (15 μm or less) and 1.5 parts by weight of a leveling agent (manufactured by San Nopco, Perenol S4) by stirring and mixing. The viscosity of the mixture is 23 ± 1
The temperature was adjusted to 45,000-49,000 cps at ℃.

[Curing Agent Composition H] 6.5 parts by weight of an imidazole curing agent (2E4MZ-CN, manufactured by Shikoku Chemicals).

Manufacturing of Printed Wiring Board FIGS. 13 to 30 are longitudinal sectional views of a printed wiring board according to the present invention, which are shown according to an example manufacturing process. (1) As shown in FIG. 13, a starting material is a copper clad laminate 6 in which 18 μm copper foil 5 is laminated on both sides of a substrate 4 made of glass epoxy resin or BT (bismaleimide triazine) resin having a thickness of 1 mm. And

First, as shown in FIG. 14, the copper-clad laminate 6 is formed by drilling a drill hole 7, performing electroless plating, and etching it in a pattern to form inner layer on both surfaces of the substrate 6. A copper pattern (lower conductor circuit) 8 and a through hole 9 were formed.

(2) The substrate having the inner layer copper pattern 8 and the through holes 9 formed thereon was washed with water and dried, and then used as an oxidation bath (blackening bath) as NaOH (10 g / L) and NaClO ₂ (40 g / L).
L), Na ₃ PO ₄ (6 g / L), NaOH (10 g
/ L), roughened surfaces 10 and 11 are provided on the surface of the inner layer copper pattern 8 and the through hole 9 by oxidation-reduction treatment using NaBH ₄ (6 g / L), and the wiring board 12 shown in FIG.
Was manufactured.

(3) The raw material composition for preparing a resin filler is mixed and kneaded to obtain a resin filler.
Within a period of time, the two surfaces of the substrate 12 are coated with a roll coater to fill the space between the conductor circuits 8 or the through holes 9 and dried at 70 ° C. for 20 minutes. The filler was filled between the conductor circuits 8 or in the through holes 9 and dried by heating at 70 ° C. for 20 minutes to form resin layers 13 and 14.

(4) One surface of the substrate after the treatment of the above (3) is subjected to belt sander polishing using # 600 belt abrasive paper (manufactured by Sankyo Rikagaku) to form the surface of the inner layer copper pattern 8 and the through holes 9. Polishing was performed so that the resin filler did not remain on the surface of the land 11, 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.

(5) Then, at 100 ° C. for 1 hour and at 120 ° C. for 3 hours.
Heat treatment was performed at 150 ° C. for 1 hour and at 180 ° C. for 7 hours to cure the resin filler, thereby producing a wiring board 15 as shown in FIG. In this wiring board 15, the surface layer portion of the resin filler filled in the through holes 9 and the like and the roughened surfaces 10, 11 on the upper surface of the inner conductor circuit 8 are removed, and both surfaces of the board are smoothed and the resin layer is removed. 13 and the side surfaces of the inner conductor circuit 8 and the land surfaces of the through holes 9 are roughened surfaces 10a, 11
a, and the inner wall surface of the through hole 9 and the resin layer 14 are firmly adhered through the roughened surface 11a. That is, by this step, the surfaces of the resin layers 13 and 14 and the surface of the inner layer copper pattern 8 become flush with each other.

(6) Printed wiring board 1 on which a conductor circuit is formed
5 was subjected to alkali degreasing and soft etching, followed by treatment with a catalyst solution comprising palladium chloride and an organic acid to give a Pd catalyst, and after activating this catalyst, copper sulfate 3.2 × 10 −10 ^{− 2} mol / L, nickel sulfate 3.9 × 1
0 ^-3 mol / L, sodium citrate 5.4 × 10 ^-2 mol / L, sodium hypophosphite 3.3 × 10 ^-1 mol / L,
Surfactant (Nissin Chemical Industries, Surfel 465)
As shown in FIG. 16, the substrate was immersed in an electroless plating solution consisting of 1.1 × 10 ⁻⁴ mol / L and PH = 9, and was vibrated and rocked at a rate of once per 4 seconds after immersion for 1 minute. And copper conductor circuit 8
And roughened layers 16 and 17 of a needle-like alloy made of Cu-Ni-P were provided on the surface of the land of the through hole 9.

Further, Cu-Sn substitution reaction was carried out under the conditions of tin borofluoride 0.1 mol / L, thiourea 1.0 mol / L, temperature 35 ° C., PH = 1.2, and the roughened layers 16 and 17 A 0.3 μm thick Sn layer was provided on the surface. The Sn layer is not particularly shown.

(7) The raw material composition for preparing the interlayer resin insulating agent was stirred and mixed, and the viscosity was adjusted to 1.5 Pa · s to obtain an interlayer resin insulating agent (for lower layer). Next, the raw material composition for preparing the adhesive for electroless plating of A was stirred and mixed, and the viscosity was adjusted to 7 Pa · s to obtain an adhesive solution for electroless plating (for the upper layer).

(8) On both surfaces of the substrate 18 of (6),
Apply the interlayer resin insulating material (for lower layer) having a viscosity of 1.5 Pa · s obtained in (7) by a roll coater within 24 hours after preparation, leave it in a horizontal state for 20 minutes, and then at 60 ° C for 30 minutes Is dried (prebaked), and then the viscosity of 7 Pa · obtained in the above (7) is obtained.
s photosensitive adhesive solution (for upper layer) is applied within 24 hours after preparation, left in a horizontal state for 20 minutes, and then
Then, an adhesive layer 19 having a thickness of 35 μm as shown in FIG. 17 was formed.

(9) As shown in FIG. 18, a black circle 20 of 85 μmφ is formed on both sides of the substrate on which the adhesive layer 19 has been formed in the above (8).
The printed photomask film 21 was adhered and exposed at 500 mJ / cm ² using an ultra-high pressure mercury lamp. The substrate is spray-developed with a DMTG solution, and further exposed to 3000 mJ / cm ² by an ultra-high pressure mercury lamp, and heated (post-baked) at 100 ° C. for 1 hour, 120 ° C. for 1 hour, and then at 150 ° C. for 3 hours. As a result, as shown in FIG. 19, a thickness of 35 μm having an opening (opening for forming a via hole) 22 of 85 μmφ with excellent dimensional accuracy corresponding to the photomask film 21 is formed.
m interlayer resin insulation layer (two-layer structure) 19. Note that the tin plating layer was partially exposed in the opening 22 serving as a via hole.

(10) The substrate in which the openings 22 are formed is immersed in chromic acid for 19 minutes to dissolve and remove the epoxy resin particles present on the surface of the interlayer resin insulating layer 19, whereby the interlayer resin insulating layer 19 The surface was roughened to form roughened surfaces 23 and 24 as shown in FIG. 20, and then immersed in a neutralizing solution (manufactured by Shipley) and then washed with water.

Further, by applying a palladium catalyst (manufactured by Atotech) to the surface of the substrate subjected to the surface roughening treatment (roughening depth: 6 μm), the surface 23 of the interlayer resin insulation layer 19 and the inner wall surface of the via hole opening 24 and the catalyst core were attached.

(11) The wiring board thus formed is
The substrate was immersed in an electroless copper plating aqueous solution having the following composition to form an electroless copper plating film 25 having a thickness of 0.6 μm on the entire rough surface as shown in FIG. [Electroless plating aqueous solution] EDTA 50 g / L Copper sulfate 10 g / L HCHO 8 mL / L NaOH 9 g / L α, α'-bipyridyl 80 mg / L PEG 0.1 g / L [Electroless plating conditions] 70 ° C. 30 minutes at liquid temperature

(12) As shown in FIG. 22, a commercially available photosensitive dry film 27 on which a black circle 26 is printed is stuck on the electroless copper plating film 25 formed in the above (11), and a mask is placed. Then, exposure was performed at 100 mJ / cm ² and development processing was performed using 0.8% sodium carbonate, thereby providing a plating resist 28 having a thickness of 15 μm as shown in FIG.

(13) Next, electrolytic copper plating is applied to the non-resist-formed portion under the following conditions, and a thickness
A μm electrolytic copper plating film 29 was formed. [Electroplating aqueous solution] Sulfuric acid 180 g / L Copper sulfate 80 g / L Additive (captoside GL, manufactured by Atotech Japan) 1 mL / L [Electroplating conditions] Current density 1 A / dm ² hours 30 minutes Temperature Room temperature

(14) After removing and removing the plating resist 28 with 5% KOH, the electroless plating film 25 under the plating resist 28 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide. As shown in FIG. 25, a thickness of 18 μm including the electroless copper plating film 25 and the electrolytic copper plating film 29
Of the conductor circuit 30 (including the via hole 31) was formed.

(15) The same treatment as in (6) was performed to form a roughened surface made of Cu-Ni-P, and the surface was further substituted with Sn. (16) By repeating the steps (7) to (15),
Further, an upper layer conductive circuit was formed to obtain a multilayer wiring board.

(17) The conductor circuit on the surface layer was treated with an etching solution comprising 10 parts by weight of an imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride, using a trade name of “Mech etch bond” manufactured by Mec Corporation. Spraying was performed, and etching treatment was performed by feeding with a transport roll, thereby forming a roughened surface 32 having a thickness of 3 μm as shown in FIG. No tin substitution was performed on the roughened surface.

This roughened surface was taken with an electron scanning microscope (× 500
When measured from directly above at 0), in the range of 25 μm ^2, an average of 11 anchor-like portions 1, 11 hollow portions and 22 ridge lines as shown in FIGS.

(18) On the other hand, 60% by weight dissolved in DMDG
Cresol novolak epoxy resin (Nippon Kayaku)
46.67 g of a sensitizing oligomer (molecular weight 4000) obtained by acrylizing 50% of the epoxy groups of the above, 15.0 g of a 80% by weight bisphenol A type epoxy resin (Epicoat 1001 manufactured by Yuka Shell) dissolved in methyl ethyl ketone, and imidazole curing 1.6 g of an agent (2E4MZ-CN, manufactured by Shikoku Chemicals Co., Ltd.), a polyacrylic monomer (R604, manufactured by Nippon Kayaku, a photosensitive monomer)
3 g), 1.5 g of polyacrylic monomer (Kyoeisha Chemical, DPE6A), dispersion antifoaming agent (Sannopco,
S-65) 0.71 g, and 2 g of benzophenone (Kanto Chemical) as a photoinitiator was added to the mixture.
0.2 of Michler's ketone (Kanto Chemical) as photosensitizer
In addition, a composition for solder resist whose viscosity was adjusted to 2.0 Pa · s at 25 ° C. was obtained. The viscosity was measured using a B-type viscometer (Tokyo Keiki, DVL-B type) at 60 rpm with rotor N.
In the case of o.4 and 6 rpm, rotor No.3 was used.

(19) The solder resist composition 33 was applied to both sides of the multilayer wiring board obtained in the above (16) in a thickness of 20 μm as shown in FIG. Then 70 ° C
28 for 30 minutes at 70 ° C.
As shown in FIG. 7, a 5 mm-thick photomask film 35 on which a circular pattern (mask pattern) 34 was drawn was placed in close contact, exposed to ultraviolet rays of 1000 mJ / cm ² , and subjected to DMTG development processing. Then, heat treatment was further performed at 80 ° C. for 1 hour, at 100 ° C. for 1 hour, at 120 ° C. for 1 hour, and at 150 ° C. for 3 hours. As shown in FIG. A solder resist layer (thickness: 20 μm) having openings (including a land portion 37) (opening diameter: 200 μm)
Was formed, and the printed wiring board 39 was manufactured.

(20) Next, the substrate 39 on which the solder resist layer 38 was formed was electroless nickel (pH = 5) consisting of 30 g / L of nickel chloride, 10 g / L of sodium hypophosphite, and 10 g / L of sodium citrate. Immersion in the plating solution for 20 minutes, as shown in FIG.
m of the nickel plating layer 40 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, and sodium hypophosphite 10 g / L in an electroless gold plating solution at 93 ° C. for 23 seconds to form a 0.03 mm thick layer on the nickel plating layer 40.
A gold plating layer 41 of μm was formed.

(21) Solder paste is printed on the opening of the solder resist layer 38 and reflowed at 200 ° C. to form a solder bump (solder body) 42.
A printed wiring board 43 having the solder bumps 42 was manufactured. In this printed wiring board, normal wiring (75 μm) was used.
(m line width) and fine wiring (50 μm line width) were provided. In the fine wiring part, a part having a low wiring density (interval of 400 μm) and a part having a high wiring density (interval of 50 μm) were provided.

Embodiment 2 FIG. 31 is a sectional view of a printed wiring board of this embodiment. This example is basically the same as Example 1, except that the process (1)
7), the roughened surface of the surface conductor circuit (solder pad conductor circuit) is replaced with a metal layer 51 shown in FIGS.
Covered. Nickel is used as the metal, and the coating is
Electroless plating was used. The thickness of the obtained nickel layer is
It was 0.04 μm.

In this example, the steps (18) to (21) allow the nickel plating layer 52 on the nickel layer 51 to be formed in the opening of the solder resist layer 38 as shown in FIG.
A solder bump (solder body) 54 was formed via the gold plating layer 53 thereon.

Example 3 Basically the same as Example 2, except that instead of a nickel layer formed by electroless plating, a tin layer formed by displacement plating was used as a metal layer covering the roughened surface of the conductor circuit for solder pads. Using. The thickness of this tin layer was 0.03 μm.

Example 4 Basically the same as Example 2, except that a zinc layer formed by electroless plating was used instead of a nickel layer formed by electroless plating instead of a nickel layer formed by electroless plating. Was used. The thickness of the zinc layer was 0.05 μm.

Example 5 Basically the same as Example 2, except that instead of a nickel layer formed by electroless plating, a metal layer formed by vapor deposition was used instead of a nickel layer formed by electroless plating. Was. This metal layer is composed of iron and cobalt,
It had a thickness of μm.

Comparative Examples 1 and 2 Basically the same as in Example 1, but in Comparative Example 1, NaOH (10 g /
L), NaClO ₂ (40 g / L), Na ₃ PO ₄ (6 g / L), and NaOH (10 g / L), NaBH ₄ (6 g / L)
A roughened surface was formed by a blackening-reduction treatment using L).
Further, in Comparative Example 2, a copper sulfate 3.2 ×
10 ^-2 mol / L, nickel sulfate 3.9 × 10 ^-3 mol / L
L, complexing agent 5.4 × 10 ⁻² mol / L, sodium hypophosphite 3.3 × 10 ⁻¹ mol / L, surfactant (Sufiru 465, manufactured by Nissin Chemical Industry) 1.1 × 10 ^-4 mol / L,
A roughened layer was formed from an electroless plating solution having a pH of 9 with an acicular alloy made of copper-nickel-phosphorus. Also in the printed wiring boards of Comparative Examples 1 and 2, the same portions of the normal wiring and the fine wiring as those of the first embodiment, the portion having the low wiring density and the portion having the high wiring density were provided.

Comparative Example 3 Basically the same as Example 2 except that the conductor circuit on the surface layer
As an oxidation bath (blackening bath), NaOH (10 g / L), NaClO ₂
(40 g / L), Na ₃ PO ₄ (6 g / L), and a roughening surface by blackening-reduction treatment using NaOH (10 g / L) and NaBH ₄ (6 g / L) as a reducing bath. Formed. Also in the printed wiring board of this example, the same portions as those of the first embodiment, that is, the portion of the normal wiring and the fine wiring, the portion having the low wiring density, and the portion having the high wiring density were provided.

Comparative Example 4 Basically the same as Example 2, except that the conductor circuit on the surface layer
3.2 × 10 ^-2 mol / L copper sulfate, 3.9 × nickel sulfate
10 ⁻³ mol / L, complexing agent 5.4 × 10 ⁻² mol / L, sodium hypophosphite 3.3 × 10 ⁻¹ mol / L, surfactant (Surfir 465, manufactured by Nissin Chemical Industry Co., Ltd.) ) 1.1 × 10
^-4 mol / L, PH = 9
The roughened layer was formed by a needle-like alloy made of nickel-phosphorus. Also in the printed wiring board of this example, the first embodiment
The same normal wiring and fine wiring, a low wiring density part, and a high wiring density part were provided.

Solder Resist Layer Peeling Test The printed circuit boards produced in Example 1 and Comparative Examples 1 and 2 were tested for solder resist layer peeling after forming the solder resist layer and after a reliability test (heat cycle conditions). In addition, the presence or absence of the connection failure between the conductor circuits was compared in a portion where the wiring density was low and in a portion where the wiring density was low, and the remaining organic residue at the bottom of the opening was confirmed. Table 1 shows the results.

[0153]

[Table 1]

As shown in Table 1, in the printed wiring board of Example 1, no peeling of the resist layer and no connection failure of the conductor circuit occurred, and no organic residue was found. In the printed wiring board of Comparative Example 1, peeling occurred in a portion where the wiring density was low after the heat cycle, and in the printed wiring board of Comparative Example 2, connection failure of the conductor circuit occurred, and the organic residue remained at the bottom of the opening. confirmed.

Test for peeling solder resist layer and soldering
Peeling test Examples 2-5 bump it, the printed circuit board produced in Comparative Example 3 and 4, after the reliability test and after the solder bump formation (heat cycle condition), peeling of the solder resist layer and solder bumps, cracks, etc. Inspection, the peel strength of the solder bump was measured, and a continuity test was performed with a checker to determine the presence or absence of disconnection or short circuit. Table 2 shows the results.

[0156]

[Table 2]

As shown in Table 2, the printed wiring boards of Examples 2 to 5 had no peeling of the solder resist layer and the solder bumps, no cracks, and the continuity test as compared with the wiring boards of Comparative Examples 3 and 5. And the shear strength of the solder ball was excellent. Further, even after the reliability test, the strength of the solder resist layer and the solder bump was sufficiently maintained, and there was no disconnection or short circuit.

[0158]

As described above, in the printed wiring board of the present invention, the roughened surface of the predetermined shape is formed on the surface of the conductor circuit for the solder pad, and the solder resist layer is firmly formed through the roughened surface. When the solder resist layer is removed at the solder bump formation part and the contact area between the conductor circuit and the solder resist layer is reduced, or when the conductor circuit is made of fine wiring and the wiring density is low However, sufficient adhesion between the conductor circuit and the solder resist layer can be ensured.

Further, in the printed wiring board of the present invention, no residue of the solder resist resin remains on the roughened surface exposed at the opening for forming the solder bump, the adhesiveness to the metal under the bump is excellent, and the solder bump It does not cause conduction failure in the formed part.

Furthermore, the printed wiring board of the present invention has excellent adhesion to the solder resist layer and adhesion to the metal under the bumps by coating the roughened surface of the conductor circuit for solder pads with a metal layer. Since the shape and the strength are maintained, the strength of the solder bump is remarkably increased, and the falling off of the solder bump can be prevented.

[Brief description of the drawings]

FIG. 1 is a drawing substitute photograph of a roughened surface according to an example of the present invention.

FIG. 2 is a drawing substitute photograph of a roughened surface of another example according to the present invention.

FIG. 3 is a drawing substitute photograph of a roughened surface of still another example according to the present invention.

FIG. 4 is a schematic view of a roughened surface according to the present invention.

FIG. 5 is a schematic view of a roughened surface according to the present invention.

FIG. 6 is a schematic view of a roughened surface according to the present invention.

FIG. 7 is a schematic diagram of a roughened surface according to the present invention.

FIG. 8 is a schematic view of a roughened surface according to the present invention.

FIG. 9 is a cross-sectional view of another roughened surface according to the present invention.

FIG. 10 is a sectional view of another roughened surface according to the present invention.

FIG. 11 is a cross-sectional view of another roughened surface according to the present invention.

FIG. 12 is a cross-sectional view of another roughened surface according to the present invention.

FIG. 13 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 14 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 15 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 16 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 17 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 18 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 19 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 20 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 21 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 22 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 23 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 24 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 25 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 26 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 27 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 28 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 29 is a manufacturing process diagram of the multilayer printed wiring board as an example according to the present invention.

FIG. 30 is a manufacturing process diagram of an example of a multilayer printed wiring board according to the present invention.

FIG. 31 is a sectional view of another example of a multilayer printed wiring board according to the present invention.

FIG. 32 is a drawing substitute photograph of a roughened layer made of a needle-shaped alloy.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Anchor part 2 Depression part 3 Ridge line 4 Substrate 5 Copper foil 6 Copper clad laminated board 7 Drill hole 8 Inner layer copper pattern (lower conductor circuit) 9 Through hole 10, 10a, 11, 11a, 23, 24, 32 Roughened surface 12, 15, 18 Wiring board 13, 14 Resin layer 16, 17 Roughened layer 19 Adhesive layer 20, 26 Black circle 21, 35 Photomask film 22 Opening (opening for forming via hole) 25 Electroless copper plating film 27 Photosensitive Conductive dry film 28 Plating resist 29 Electrolytic copper plating film 30 Conductor circuit 31 Via hole 33 Composition for solder resist 34 Circular pattern (mask pattern) 36 Solder pad part 37 Via hole and land part thereof 38 Solder resist layer 39, 43 Printed wiring Plates 40,52 Nickel plating layer 41,53 Gold plating layer 42,54 Bumps (solder body) 51 metal layer

Claims (17)

[Claims] 1. A printed wiring board comprising: a conductor circuit for solder pads; and a solder resist layer on the conductor circuit for solder pads, wherein an opening for providing a solder body is formed in the solder resist layer. The solder pad conductor circuit has a roughened surface that is treated with an etchant containing a cupric complex and an organic acid, and the solder resist layer is provided on the roughened surface. A printed wiring board, characterized in that: 2. A printed wiring board comprising: a solder pad conductor circuit; and a solder resist layer on the solder pad conductor circuit, wherein an opening for providing a solder body is formed in the solder resist layer. The conductor circuit for a solder pad has a roughened surface, the roughened surface has a plurality of anchors, dents, and ridges, and the anchors, the dents, and the ridges are It is formed in a dispersed manner, and the adjacent anchor-shaped portions are connected by the ridge line, and the dent portion is surrounded by the anchor-shaped portion and the ridge line, and the solder resist layer is formed on the roughened surface. A printed wiring board characterized by being provided in a printed circuit board. 3. A printed wiring board comprising: a conductor circuit for a solder pad; and a solder resist layer on the conductor circuit for a solder pad, wherein an opening for providing a solder body is formed in the solder resist layer. The solder pad conductor circuit has a roughened surface treated with an etching solution containing a cupric complex and an organic acid, and the roughened surface is formed of titanium, zinc, iron, indium, and thallium. , A metal layer of at least one metal selected from the group consisting of cobalt, nickel, tin, lead, bismuth and a noble metal, and the solder resist layer is provided on the roughened surface. The printed wiring board. 4. A printed wiring board comprising: a conductor circuit for solder pads; and a solder resist layer on the conductor circuit for solder pads, wherein an opening for providing a solder body is formed in the solder resist layer. The conductor circuit for a solder pad has a roughened surface, the roughened surface has a plurality of anchors, dents, and ridges, and the anchors, the dents, and the ridges are Being formed in a dispersed manner, the adjacent anchor-shaped portions are connected by the ridge line, and the dent portion is surrounded by the anchor-shaped portion and the ridge line, and the roughened surface is titanium, zinc,
Iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and coated with a metal layer of at least one metal selected from the group consisting of noble metals,
The printed wiring board, wherein the solder resist layer is provided on the roughened surface. 5. The conductor circuit for a solder pad according to claim 5, wherein
The printed wiring board according to claim 1, wherein the thickness is 50 μm or less. 6. The printed wiring board according to claim 3, wherein the metal layer has a thickness of 0.01 to 1 μm. 7. The method according to claim 2, wherein the depression is formed by etching metal crystal particles.
Or the printed wiring board according to 4. 8. The printed wiring board according to claim 2, wherein the recess is hollowed out in a substantially polyhedral shape. 9. The method according to claim 2, wherein the ridge line is formed by dropping of adjacent metal crystal particles.
Or the printed wiring board according to 4. 10. The printed wiring board according to claim 2, wherein the ridge line is branched. 11. The printed wiring board according to claim 2, wherein the ridge is sharp. 12. The printed wiring board according to claim 2, wherein the anchor-shaped portion is formed by etching metal crystal particles around the anchor-shaped portion. 13. The printed wiring according to claim 2, wherein each of the anchor-shaped portions is dispersed, and the anchor-shaped portion is surrounded by the recessed portion and the ridge line. Board. 14. The printed wiring board according to claim 1, wherein the roughened surface has a maximum roughness (Rmax) of 0.5 to 10 μm. 15. The roughened surface has an average of 2 to 100 anchor portions and an average of 2 to 100 recesses per 25 μm ^2. 5. The printed wiring board according to 2 or 4. 16. A printed wiring board comprising a solder pad conductor circuit and a solder resist layer on the solder pad conductor circuit, wherein an opening for providing a solder body is formed in the solder resist layer. In obtaining, the conductor circuit for a solder pad is treated with an etchant containing a cupric complex and an organic acid to form a roughened surface on the conductor circuit for a solder pad, and the roughened surface is formed of titanium. , Coated with a metal layer of at least one metal selected from the group consisting of zinc, iron, indium, thallium, cobalt, nickel, tin, lead, bismuth and noble metals,
A method for manufacturing a printed wiring board, comprising: providing the solder resist layer on the metal layer. 17. The method for manufacturing a printed wiring board according to claim 16, wherein the roughened surface is heat-treated at a temperature in the range of 50 to 250 ° C. to cover the metal layer.