JP2001257451A - Printed wiring board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board capable of securing high reliability of insulation by making migration resistance excellent, and a method of manufacturing the printed wiring board. SOLUTION: Through holes 13 in an insulating substrate 11 are filled with conductive paste 14 containing conductive powder 15. Copper foils 16, 17 are stacked on respective surfaces of the insulating substrate 11, and are compressed and heated to coat the surfaces. Then, they are etched to form wiring patterns 18, 19. By immersing the substrate into an organic rust-preventing agent solution 20, organic rust-preventing agent layers 21a, 22a are formed at least on end faces of the wiring patterns 18, 19. These organic rust-preventing agent layers 21a, 22a are utilized as migration suppressing layers for the wiring patterns 18, 19. Instead of the organic rust-preventing agent layers 21a, 22a, metal layers 31a, 32a or compound layers 41a, 42a may be used.

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 a method for manufacturing the printed wiring board, and more particularly, to a technique for securing high insulation reliability required for a printed wiring board suitable for miniaturization and high density. It is about.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller and higher in density, not only in industrial fields, but also in consumer fields.
There is an increasing demand for printed wiring boards suitable for miniaturization and high density.

As an example of a printed wiring board created in response to such a demand, there is an all-layer IVH resin multilayer printed wiring board disclosed in Japanese Patent Application Laid-Open No. 6-268345 (IVH: interstitial via hole). ).
The outline will be described below.

First, as shown in FIG. 9A, a compressible prepreg having a release film 12 adhered on both surfaces thereof is prepared as an insulating base material 11. Note that the release film 12 includes polyethylene terephthalate and the like. As the insulating base material 11, there is a material obtained by impregnating an aromatic polyamide fiber with an epoxy resin.

Next, through holes 13 are formed at predetermined positions in the insulating base material 11 by using a laser processing method.

Next, as shown in FIG. 9B, a conductive paste 14 is filled in the through holes 13 of the insulating base material 11 using a squeegee or the like. This conductive paste 14 contains conductive powder 15.

Next, as shown in FIG. 9C, the release film 12 adhered to the insulating base material 11 is peeled off and removed.

Next, as shown in FIG. 9D, copper foils 16 and 17 are laminated on both upper and lower surfaces of the insulating base material 11.
Then, the insulating base material 11 and the copper foils 16 and 17 are heated while being compressed in the thickness direction. Thereby, the insulating base material 11 and the conductive powder 15 contained in the conductive paste 14 and filled in the through holes 13 are both compressed, and
Copper foils 16 and 17 are adhered on the surface of the insulating base material 11.
This is referred to as a semi-finished printed wiring board A0.

Next, as shown in FIG. 9E, wiring patterns 18 and 19 are formed by etching the copper foils 16 and 17 applied on the surface of the insulating base material 11. Thereby, the wiring patterns 18 opposed to each other with the insulating base material 11 interposed therebetween,
19 are electrically connected to each other via the conductive powder 15 filled in the through holes 13 of the insulating base material 11. This is referred to as a semi-finished printed wiring board A1.

[0010]

In the case of a printed wiring board corresponding to the miniaturization and high density of electronic equipment, the distance between adjacent wiring patterns 18 on the same surface becomes shorter. For example, 100μm, 50μm or 25μ
m and so on.

However, the metal constituent atoms move from the end face of the wiring pattern 18, and the adjacent wiring pattern 1
Ion migration occurs so as to approach 8.

Wiring patterns 18, 18 adjacent on the same surface
The smaller the distance between the two, the greater the possibility of short-circuit failure or disconnection failure due to this migration.

In order to suppress the migration of the wiring patterns 18, 18, it is conceivable to form a migration suppressing layer on the surface of the copper foil 16 adhered to the insulating base material 11 in the above-mentioned prior art.

However, when the copper foil 16 is etched to form the wiring pattern 18, the migration suppressing layer is also removed, so that the surface of the formed wiring pattern 18 that is not parallel to the insulating base 11 is formed. That is, the end face of the wiring pattern 18 is not covered with the migration suppressing layer. Therefore,
The possibility that migration occurs on the end face of the wiring pattern 18 increases, and it becomes difficult to secure insulation reliability in the printed wiring board.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a printed wiring board and a printed wiring which can ensure high insulation reliability by improving migration resistance. It is intended to provide a method for manufacturing a board.

[0016]

According to the present invention, there is provided a printed wiring board for solving the above-mentioned problems, wherein a migration suppressing layer is formed on at least an end face of the wiring pattern. Examples of the migration suppressing layer include an organic rust inhibitor layer, a metal layer, and a compound layer. The wiring pattern is preferably a wiring pattern made of copper, but is not necessarily limited to the wiring pattern, and the material forming the wiring pattern is arbitrary.

Since the migration suppressing layer is formed on the end face of the wiring pattern, the migration resistance of the wiring pattern can be improved. As a result, the fine wiring of the high-density integrated printed wiring board can be improved. Therefore, even if the distance between adjacent wiring patterns is considerably reduced, high insulation reliability can be provided.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be generally described.

According to a first aspect of the present invention, there is provided a printed wiring board having a wiring pattern formed on an insulating base material, wherein a migration suppressing layer is formed on an end face of the wiring pattern. And

The operation according to the first aspect of the present invention is substantially the same as that described in the above section [Means for Solving the Problems]. That is, high insulation reliability can be provided even in a high-density integrated type printed wiring board in which the distance between adjacent wiring patterns is considerably reduced due to miniaturized wiring.

A printed wiring board according to a second aspect of the present invention is the printed wiring board according to the first aspect, wherein the migration suppressing layer is an organic rust preventive layer. Some organic rust preventive layers have corrosion resistance to the constituent metals of the wiring pattern and also have an excellent migration suppressing effect. Such an organic rust preventive layer is used as a migration suppressing layer for the wiring pattern. In this case, high insulation reliability can be provided even in a high-density integrated printed wiring board in which the distance between adjacent wiring patterns is considerably reduced due to miniaturized wiring.

The printed wiring board according to a third aspect of the present invention is the printed wiring board according to the second aspect, wherein the organic rust preventive layer is at least one kind of 1,2,3-benzotriazole or a benzotriazole compound. It is that there is. 1,2,3-Benzotriazole and benzotriazole-based compounds have a very excellent migration inhibitory effect on constituent metals of wiring patterns, particularly copper, among organic rust preventives. Even in a high-density integrated type printed wiring board in which the interval between patterns is considerably small, it is highly effective to provide high insulation reliability.

A printed wiring board according to a fourth aspect of the present invention is the printed wiring board according to the first aspect, wherein the migration suppressing layer is a metal layer having better migration resistance than the wiring pattern. I do. Since the migration suppressing layer is made of a metal layer having excellent migration resistance, it is possible to enhance the bonding property between the wiring pattern, which is a metal, and the metal layer of the migration suppressing layer. By forming a layer on the end face of the wiring pattern as a migration suppressing layer, high insulation reliability can be achieved even in a high-density integrated printed wiring board in which the distance between adjacent wiring patterns is considerably reduced due to miniaturized wiring. It is possible to give.

The printed wiring board according to a fifth aspect of the present invention is the printed wiring board according to the fourth aspect, wherein the metal layer is one or arbitrarily selected from the group consisting of nickel, palladium, platinum, zinc, and cadmium. It is a metal layer made of a plurality of metals. Nickel, palladium, platinum, zinc, and cadmium are less likely to migrate than copper and have high insulation even in high-density integrated printed wiring boards where the distance between adjacent wiring patterns is considerably smaller due to miniaturized wiring. The effectiveness of providing reliability is high.

The printed wiring board according to the sixth aspect of the present invention is the printed wiring board according to the fourth or fifth aspect, wherein the printed wiring board is provided on the surface of the insulating base in the wiring pattern so as to be continuous with the metal layer as the migration suppressing layer. The same metal layer is also formed on the parallel surface layer. In the case of the organic rust preventive layer, if the organic rust preventive layer remains on the surface layer parallel to the surface of the insulating base material, it adversely affects the electrical connection with components mounted on the printed wiring board. Can occur. Therefore, when there is a possibility of such an adverse effect, it is desirable to remove as much as possible the surface layer portion of the suppression layer in the surface continuity organic rust inhibitor layer that is parallel to the surface of the insulating base material. However, in the case of the metal layer, unlike the organic rust preventive layer, such a risk is often small, and in such a case, it is possible to leave the metal layer without removing it. ing. Not removing it is advantageous for reducing man-hours and cost.

The printed wiring board according to a seventh aspect of the present invention is the printed wiring board according to the first aspect, wherein the migration suppressing layer is a metal oxide, nitride, or sulfide having a higher migration resistance than the wiring pattern. And a compound layer mainly composed of Since the migration suppressing layer is made of a compound layer mainly composed of a metal oxide, nitride or sulfide having excellent migration resistance, the bonding property between the metal wiring pattern and the compound layer of the migration suppressing layer is improved. Since the above compound layer has a higher migration suppressing effect than a simple metal layer, by forming such a compound layer as a migration suppressing layer on the end face of the wiring pattern, miniaturization can be achieved. Even in a high-density integrated type printed wiring board in which the distance between adjacent wiring patterns is considerably reduced due to wiring, high insulation reliability can be provided.

The printed wiring board according to an eighth aspect of the present invention is the printed wiring board according to the seventh aspect, wherein the compound layer is one or arbitrarily selected from the group consisting of nickel, palladium, platinum, zinc, and cadmium. It is said to be an oxide or nitride or sulfide of a plurality of metals. Nickel, palladium, platinum, zinc, and cadmium are less likely to migrate than copper, and even in high-density integrated printed wiring boards where the distance between adjacent wiring patterns is considerably smaller due to miniaturized wiring,
It is highly effective to provide high insulation reliability.

The printed wiring board according to a ninth aspect of the present invention is the printed wiring board according to the first to eighth aspects, wherein a through hole is formed in the insulating base material, and the through hole is filled with a conductive paste. A wiring pattern formed on the surface of the insulating base is joined to the conductive paste.
In general, the conductive paste contains conductive powder. This means that a double-sided wiring board is formed by performing via bonding as vertical wiring. Also,
This is also the development of a multilayer wiring structure described later on a printed wiring board. Double-sided wiring boards and printed wiring boards with a multilayer wiring structure are typical of high-density integrated type printed wiring boards, and the spacing between adjacent wiring patterns has been considerably reduced due to the finer wiring. As a result, high insulation reliability can be provided.

A printed wiring board according to a tenth aspect of the present invention is the printed wiring board according to the first to ninth aspects, wherein the wiring patterns formed on the upper and lower surfaces of the insulating base are formed with through holes formed in the insulating base. A plurality of layers electrically connected via conductive powder in a conductive paste filled in a plurality of layers and integrated to form a multilayer wiring structure. This is a printed wiring board having a multilayer wiring structure by repeating via bonding as vertical wiring in multiple layers. Printed wiring boards having a multilayer wiring structure are typical of high-density and highly integrated type printed wiring boards, and the spacing between adjacent wiring patterns is extremely small due to the miniaturized wiring. It is possible to provide insulation reliability.

The eleventh and subsequent inventions relate to a method for manufacturing a printed wiring board.

The method of manufacturing a printed wiring board according to the eleventh aspect of the present invention includes a step of forming a wiring pattern on a surface of an insulating base material, and a step of forming a migration suppressing layer on an end face of the wiring pattern. And

According to a twelfth aspect of the present invention, in the method for manufacturing a printed wiring board according to the eleventh aspect, the migration suppressing layer is formed on an end face of the wiring pattern by applying or spraying an organic rust inhibitor solution. It is.

The method for manufacturing a printed wiring board according to the thirteenth aspect of the present invention is the method according to the eleventh aspect, wherein the insulating base material on which the wiring pattern is formed is immersed in an organic rust inhibitor solution to form an end face of the wiring pattern. Then, the migration suppressing layer is formed.

According to a fourteenth aspect of the present invention, in the method of manufacturing a printed wiring board according to the eleventh aspect, the migration suppressing layer is formed on an end face of the wiring pattern by metal plating.

According to a fifteenth aspect of the present invention, in the method for manufacturing a printed wiring board according to the eleventh aspect, the metal is plated, and then the metal is oxidized, nitrided or sulfurized to form an end face of the wiring pattern. The migration suppressing layer is formed.

According to the eleventh to fifteenth aspects of the present invention, when manufacturing a high-density integrated printed wiring board for the above-described reason, the distance between adjacent wiring patterns is considerably small due to miniaturized wiring. Despite becoming
It is possible to manufacture a high-density integrated printed wiring board having high insulation reliability.

The method of manufacturing a printed wiring board according to a sixteenth aspect of the present invention is the method according to the eleventh to fifteenth aspects, wherein the wiring pattern extends from a surface layer portion parallel to a surface of the insulating base material to an end face of the wiring pattern. The migration suppressing layer is formed. this is,
Corresponding to the printed wiring board of the sixth aspect, the surface layer of the suppression layer parallel to the surface of the insulating base in the surface continuity metal layer can be reduced in cost by reducing the number of steps by leaving it as it is. Becomes

The method for manufacturing a printed wiring board according to a seventeenth aspect of the present invention is the method for manufacturing a printed wiring board according to the sixteenth aspect, wherein the migration suppressing layer is formed on a surface layer portion of the wiring pattern parallel to the surface of the insulating base material. The surface of the layer is removed by polishing or the like. this is,
This is in contrast to the sixteenth aspect. In the case of an organic rust preventive layer, if the organic rust preventive layer remains in a layer part parallel to the surface of the insulating base material, it adversely affects the electrical connection with components mounted on the printed wiring board. Can occur. Therefore, by removing the surface layer of the suppression layer by polishing or the like, it is possible to prevent trouble in component mounting.

The method for manufacturing a printed wiring board according to the eighteenth aspect of the present invention is the method according to the eleventh to seventeenth aspects, wherein the step of forming a wiring pattern on the surface of the insulating base material is performed on the insulating base material. Forming a through-hole and filling the through-hole with a conductive paste; and forming a wiring pattern on the surface of the insulating base in a state of bonding to the conductive paste in the through-hole. To form the wiring pattern. according to this,
It is possible to manufacture a high-density integrated printed wiring board having high insulation reliability corresponding to the printed wiring board (double-sided wiring board) of the ninth aspect.

The method for manufacturing a printed wiring board according to a nineteenth aspect of the present invention is the method according to the eighteenth aspect, wherein a metal foil is laminated on the surface of the insulating base material in a state of being bonded to the conductive paste. It is said that the wiring pattern is formed by applying heat to the insulating base material while compressing the insulating base material, applying the metal foil to the insulating base material, and processing the pressed metal foil by a photolithography method. Things. In the photolithography method, after a photosensitive resist layer is provided on a wiring pattern, the wiring pattern is exposed and developed to selectively remove the resist layer, thereby forming a wiring pattern. Copper foil is preferred as the metal foil.

According to a twentieth aspect of the present invention, in the method for manufacturing a printed wiring board according to the eleventh to nineteenth aspects, the wiring patterns formed on the upper and lower surfaces of the insulating base are formed on the insulating base. A plurality of layers electrically connected via conductive powder in a conductive paste filled in the through-hole are laminated and integrated to form a multilayer wiring structure. This makes it possible to manufacture a high-density and highly integrated printed wiring board having high insulation reliability corresponding to the printed wiring board of the tenth aspect.

The method for manufacturing a printed wiring board according to the twenty-first aspect of the present invention is directed to the method for manufacturing a printed wiring board according to the eleventh to twentieth aspects of the present invention, by using an organic rust inhibitor solution mixed etching solution. And the formation of the migration suppressing layer on the end face of the substrate at the same time. Since the patterning of the wiring pattern and the formation of the migration suppressing layer are performed at the same time, the productivity can be improved.

(Specific embodiments) Specific embodiments of a printed wiring board and a method of manufacturing a printed wiring board according to the present invention will be described in detail with reference to the drawings.

(Embodiment 1) Embodiment 1 relates to a double-sided wiring board among printed wiring boards, and a migration suppressing layer formed on an end face of a wiring pattern is formed as an organic rust inhibitor layer. Things.

1 (a) to 1 (g) are cross-sectional views illustrating process steps of a method for manufacturing a printed wiring board (double-sided wiring board) according to Embodiment 1, and FIG. 2 is a cross-sectional view of a printed wiring board as a product. FIG. Hereinafter, description will be made in order.

First, as shown in FIG. 1 (a), a material in which a release film 12 is bonded on both upper and lower surfaces of an insulating base material 11 is prepared. Note that, as the insulating base material 11, a prepreg in which aromatic polyamide fibers are impregnated with an epoxy resin and which has compressibility and has a large number of pores dispersed therein is preferable. Through holes 13 are formed at predetermined positions in the insulating base material 11 to which the release film 12 is adhered by using a laser processing method.

Next, as shown in FIG. 1B, the conductive paste 14 is filled in the through holes 13 of the insulating base material 11 using a squeegee or the like. This conductive paste 14 contains conductive powder 15.

Next, as shown in FIG. 1C, the release film 12 adhered to the insulating base material 11 is peeled and removed.

Next, as shown in FIG. 1D, copper foils 16 and 17 are laminated on both upper and lower surfaces of the insulating base material 11.
Then, the insulating base material 11 and the copper foils 16 and 17 are heated while being compressed in the thickness direction. Thereby, the insulating base material 11 and the conductive powder 15 contained in the conductive paste 14 and filled in the through holes 13 are both compressed, and the copper foils 16 and 17 are formed on the surface of the insulating base material 11. Be deposited. This is a semi-finished printed wiring board A0.

Next, as shown in FIG. 1E, the copper foils 16 and 17 adhered on the surface of the insulating base material 11 are etched by photolithography to form the wiring pattern 1.
8 and 19 are formed. The photolithography method involves masking with a photosensitive resist layer, exposing and developing in a state where a required wiring pattern is drawn, selectively removing the photosensitive resist layer, etching, and further etching the photosensitive resist layer. Is to be removed. As a result, the wiring patterns 18 and 19 facing each other with the insulating base material 11 therebetween are electrically connected to each other via the conductive powder 15 filled in the through holes 13 of the insulating base material 11. This is a semi-finished printed wiring board A1. Up to this point, it is the same as the above-described conventional technology.

That is, the printed wiring board A1 of the semi-finished product up to the above stage is the printed wiring board A of the first embodiment.
1 is the basic configuration. The printed wiring board P1 according to the first embodiment is different from the semi-finished printed wiring board A1 in that the wiring patterns 18 and 19 are not parallel to the insulating base material 11, as shown in FIG. It is characterized in that the end faces of the wiring patterns 18 and 19 are provided with organic rust preventive layers 21a and 22a. Hereinafter, the manufacturing process will be described.

In the first embodiment of the present invention, the semi-finished product printed wiring board A1 is further immersed in an organic rust inhibitor solution 20, as shown in FIG.

As a result, as shown in FIG. 1 (g), the wiring patterns 18 and 19 on the insulating base material 11 extend continuously from the surface layer parallel to the surface of the insulating base material 11 to the end faces of the wiring patterns 18 and 19. The resulting surface continuity organic rust inhibitor layers 21 and 22 are formed.

Next, as shown in FIG.
The surface continuity organic rust preventive layers 21 and 22 formed on the entire surfaces of the surfaces 8 and 19 are polished by means such as polishing, etc. The surface layer of the suppression layer parallel to
The organic rust preventive layers 21a and 22a are left only on the 19 end faces.
The organic rust preventive layers 21a and 22a adhering to the end faces of the wiring patterns 18 and 19 will be referred to as end face adhering organic rust preventive layers 21a and 22a. The end surface-adhering organic rust preventive layers 21a and 22a are
19 serves as a migration suppressing layer for the end face.

In the first embodiment, a printed wiring board P1 as a double-sided wiring board as shown in FIG. 2 is obtained as described above. FIG. 2 is a sectional view showing the structure of the printed wiring board (double-sided wiring board) P1 manufactured as described above.

The structure of the printed wiring board P1 will now be described. The insulating base material 11 and the conductive powder 1 filled in the through holes 13 formed between the upper and lower surfaces of the insulating base material 11 are formed.
5-containing conductive paste 14 and conductive paste 14 applied to upper and lower surfaces of insulating base material 11 and filled in through holes 13
Wiring patterns 18 and 19 that are electrically conductively connected via conductive powder 15 therein, and an end surface-adhering organic rust inhibitor layer 21 formed on the end surfaces of the wiring patterns 18 and 19 respectively.
a, 22a.

Next, each of the above components will be described more specifically.

A preferred example of the insulating base material 11 is a prepreg in which a base material is impregnated with a thermosetting resin to be in a semi-cured state, has compressibility, and has a large number of pores dispersed therein. it can.

Preferred examples of the base material in the insulating base material 11 include aromatic polyamide fiber base material, glass cloth base material, glass nonwoven base material, aramid cloth base material, and aramid nonwoven base material.
A liquid crystal polymer nonwoven fabric substrate can be used.

Preferable examples of the thermosetting resin in the insulating base material 11 include a phenol resin, a naphthalene resin, a urea resin, an amino resin, an alkyd resin, a silicon resin, a furan resin, an unsaturated polyester resin, and an epoxy resin. And a known thermosetting resin such as a polyurethane resin. Further, one or a plurality of arbitrarily selected from these may be combined.

As the prepreg to be used as the material of the insulating base material 11, one or more base materials arbitrarily selected from the above examples of the base material and arbitrarily selected from the above examples of the thermosetting resin. It is constituted by a combination with one or a plurality of thermosetting resins.

Preferred examples of the release film 12 include polyethylene terephthalate and the like.

The conductive paste 14 contains at least a conductive powder 15 and a thermosetting resin as constituent materials.

Preferred examples of the conductive powder 15 include, for example,
One or a plurality of conductive powders arbitrarily selected from gold, silver, copper, nickel, lead or tin, and alloys thereof can be given.

Preferable examples of the thermosetting resin include, for example, phenolic resin, naphthalene resin, urea resin, amino resin, alkyd resin, silicon resin, furan resin, unsaturated polyester resin, epoxy resin, polyurethane resin And other known thermosetting resins, and may be a combination of one or more arbitrarily selected ones among them.

Preferred examples of the wiring patterns 18 and 19 include, for example, a copper foil patterned by the etching method or the like as described above.

The end surface-adhering organic rust preventive layers 21 a, 22 a, which are characteristic components of the first embodiment, that is, the end surface-adhering organic rust preventive layers 21 a, 22 a adhered to the end surfaces of the wiring patterns 18, 19. As the original organic rust inhibitor,
Although it is possible to use rust inhibitors such as amines and chromates which are used as ordinary rust inhibitors, preferred examples of the organic rust inhibitor in the first embodiment include wiring patterns 18, Rust prevention effect, that is, migration suppression effect on copper, which is a metal constituting 19, is high.
Examples thereof include 2,3-benzotriazole and benzotriazole-based compounds.

The chemical formula of 1,2,3-benzotriazole is as follows.

[0069]

Embedded image Specific preferred examples of such 1,2,3-benzotriazole or benzotriazole-based compound include 4
-Methyl-1,2,3-benzotriazole, 5-methyl-1,2,3-benzotriazole, 1-chloro-
1,2,3-benzotriazole, 5-chloro-1,
2,3-benzotriazole, 1-hydroxy-1,
2,3-benzotriazole, 2-hydroxy-1,
Representative examples include 2,3-benzotriazole, alkali metal (sodium, potassium) salts of the above compounds, 4-carboxyl-1,2,3-benzotriazole, and ester compounds thereof.

As another method for attaching the end surface-adhering organic rust preventive layers 21a and 22a to the end surfaces of the wiring patterns 18 and 19, as a solution of 1,2,3-benzotriazole or a benzotriazole-based compound. The prepared organic rust inhibitor solution 20 is applied to the wiring patterns 18, 1.
9, or by spraying, the surface continuity organic rust preventive layers 21 and 22 are similarly adhered, and thereafter, unnecessary portions of the surface continuity organic rust preventive layers 21 and 22 are applied.
The surface layer of the suppression layer parallel to the surface of the insulating base material 11 among the surface continuity organic rust preventive layers 21 and 22 is removed by means of polishing or the like, and the end faces are formed only on the end faces of the wiring patterns 18 and 19. There is also a method of leaving the adhesive organic rust preventive layers 21a and 22a.

In the above description, the reason why the surface layer portion of the suppression layer parallel to the surface of the insulating base material 11 among the surface continuity organic rust preventive layers 21 and 22 formed on the wiring patterns 18 and 19 was removed is as follows. This is to prevent adverse effects on the electrical connection with components mounted on the printed wiring board P1. Therefore, when there is a possibility that such an adverse effect may occur, the surface continuation organic rust inhibitor layers 21 and 22 should be removed as much as possible from the surface layer of the suppression layer parallel to the surface of the insulating base material 11. Is desirable. However, when the thickness of the parallel suppression layer surface layer portion is sufficiently small and there is no possibility of such an adverse effect, it is not always necessary to remove it, and it may be left as it is, or may be polished or the like. Even if it removes with, a part may remain.

In the manner described above, the wiring patterns 18,
By providing the end surface-adhering organic rust preventive layers 21a and 22a as migration suppressing layers on the surface not parallel to the insulating base material 11 at the end surfaces of the wiring patterns 18 and 19, copper as the material of the wiring patterns 18 and 19 is provided. Corrosion resistance and migration resistance can be improved. As a result, in recent high-density integrated type printed wiring boards, the distance between adjacent wiring patterns has been considerably reduced due to the miniaturized wiring. In this case, the printed wiring board can be provided with high insulation reliability.

(Embodiment 2) Embodiment 2 relates to a double-sided wiring board among printed wiring boards, and a metal layer is used as a migration suppressing layer formed on an end face of a wiring pattern. .

3 (a) to 3 (f) are cross-sectional views illustrating the steps of a method for manufacturing a printed wiring board (double-sided wiring board) according to the second embodiment, and FIG. 4 is a cross-sectional view of the printed wiring board as a product. FIG. Hereinafter, description will be made in order.

First, as shown in FIG. 3 (a), a material in which a release film 12 is bonded on the upper and lower surfaces of an insulating base material 11 is prepared, and the insulating substrate to which the release film 12 is bonded is prepared. Through holes 13 are formed at predetermined positions in the material 11 by using a laser processing method.

Next, as shown in FIG. 3B, a conductive paste 14 containing conductive powder 15 is filled in the through holes 13 of the insulating base material 11 using a squeegee or the like.

Next, as shown in FIG. 3C, the release film 12 adhered to the insulating base material 11 is peeled off.

Next, as shown in FIG. 3D, copper foils 16 and 17 are laminated on both upper and lower surfaces of the insulating base material 11.
Then, the insulating base material 11 and the copper foils 16 and 17 are heated while being compressed in the thickness direction. Thereby, the insulating base material 11 and the conductive powder 15 contained in the conductive paste 14 and filled in the through holes 13 are both compressed, and
Copper foils 16 and 17 are adhered on the surface of the insulating base material 11.
This is a semi-finished printed wiring board A0.

Next, as shown in FIG. 3E, the copper foils 16 and 17 adhered on the surface of the insulating base material 11 are etched using photolithography to form the wiring pattern 1.
8 and 19 are formed. Thereby, the wiring patterns 18 and 19 facing each other with the insulating base material 11 interposed therebetween are connected to the insulating base material 1.
Conductive connection is made via conductive powder 15 filled in one through hole 13. This is a semi-finished printed wiring board A1. Up to this point, the operation is the same as that of the first embodiment.

That is, the printed wiring board A1 of the semi-finished product up to the above stage is the printed wiring board P of the second embodiment.
2 is the basic configuration.

Note that items which have been described in the first embodiment and which are not described again in the second embodiment also apply to the second embodiment as they are, and a detailed description thereof will be omitted. In particular, the insulating substrate 11,
Release film 12, conductive paste 14, conductive powder 1
5. Regarding the material of the wiring patterns 18 and 19, the description of the first embodiment is directly followed.

Printed Wiring Board P in Second Embodiment
2 further includes wiring patterns 18 and 1 as shown in FIG.
9 on the side not parallel to the insulating base material 11, that is, on the end faces of the wiring patterns 18 and 19, the end face adhering metal layer which is more resistant to migration and corrosion than copper which is a constituent material of the wiring patterns 18 and 19 It is characterized by having 31a and 32a. Hereinafter, the manufacturing process will be described.

According to the second embodiment of the present invention, as shown in FIG. 3F, the printed wiring board A1 of the above-mentioned semi-finished product is subjected to the wiring pattern 18 by electrolytic plating or the like. , 19 are formed with surface-continuous metal layers 31 and 32 having excellent migration resistance and corrosion resistance. The surface continuity metal layers 31 and 32 are continuous from the surface layer portions of the wiring patterns 18 and 19 parallel to the surface of the insulating base material 11 to the end faces of the wiring patterns 18 and 19.

The surface continuity metal layers 31 and 32 are metal layers made of one or more metals arbitrarily selected from the group consisting of nickel, palladium, platinum, zinc and cadmium. Such a metal has better migration resistance and corrosion resistance than the wiring patterns 18 and 19 made of copper.

Next, as shown in FIG.
The surface continuity metal layers 31 and 32 formed on the entire surfaces of the surfaces 8 and 19 are polished or the like, and the surface continuity metal layers 31 and 32 of the suppression layer surface layer parallel to the surface of the insulating base material 11 are polished or the like. The portions are removed to leave the metal layers 31a and 32a only on the end faces of the wiring patterns 18 and 19. This wiring pattern 1
The metal layers 31a and 32a adhering to the end faces 8 and 19 will be referred to as end face adhering metal layers 31a and 32a. The end surface adhering metal layers 31a and 32a serve as migration suppression layers for the end surfaces of the wiring patterns 18 and 19.

In the second embodiment, a printed wiring board P2 as a double-sided wiring board as shown in FIG. 4 is obtained as described above. FIG. 4 is a sectional view showing the structure of the printed wiring board (double-sided wiring board) P2 manufactured as described above.

The structure of the printed wiring board P2 will be described. The insulating base material 11 and the conductive powder 1 filled in the through-hole 13 formed between the upper and lower surfaces of the insulating base material 11 are formed.
5-containing conductive paste 14 and conductive paste 14 applied to upper and lower surfaces of insulating base material 11 and filled in through holes 13
Wiring patterns 18 and 19 electrically connected to each other via the conductive powder 15 therein, and end surface adhering metal layers 31 a and 3 formed on the respective end surfaces of the wiring patterns 18 and 19.
2a.

In the above description, the insulating base material 1 of the surface continuity metal layers 31 and 32 formed on the wiring patterns 18 and 19
The reason why the surface portion of the suppression layer parallel to the surface of the wiring pattern 1 was removed is that the surface portion of the suppression layer parallel to the wiring patterns 18
This is because it does not directly contribute to the insulation reliability between the eight. Therefore, it is desirable to remove as much as possible the surface layer of the suppression layer parallel to the surface of the insulating base material 11 among the surface continuity metal layers 31 and 32 that may cause the thickness of the printed wiring board P2 to increase. However, when the thickness of the parallel suppression layer surface layer portion is sufficiently small and there is no possibility of such an adverse effect, it is not always necessary to remove it, and it may be left as it is, or may be polished or the like. Even if it removes with, a part may remain.

In the manner described above, the wiring patterns 18,
In 19, an end surface adhered to a surface that is not parallel to the insulating base material 11, that is, an end surface of the wiring patterns 18 and 19, in which migration resistance and corrosion resistance as a migration suppressing layer are superior to copper which is a constituent material of the wiring patterns 18 and 19. By providing the conductive metal layers 31a and 32a,
Corrosion resistance and migration resistance of copper, which is the material of the wiring patterns 18 and 19, can be improved. As a result, in recent high-density integrated type printed wiring boards, adjacent wiring is required for fine wiring. Even if the interval between the patterns is considerably reduced, the printed wiring board can have high insulation reliability.

(Embodiment 3) Embodiment 3 relates to a double-sided wiring board among printed wiring boards. Further, a migration suppressing layer formed on an end face of a wiring pattern is formed by oxidation or nitridation of a metal layer. Alternatively, it forms a compound layer by sulfurization.

FIGS. 5 (a) to 5 (g) are process explanatory sectional views sequentially showing a method of manufacturing a printed wiring board (double-sided wiring board) according to the third embodiment. Hereinafter, description will be made in order.

FIGS. 5A to 5F are the same as FIGS. 3A to 3F in the second embodiment. In addition,
Matters that have been described in the first embodiment and that are not described again in the third embodiment also apply to the third embodiment as they are, and detailed descriptions thereof will be omitted. In particular, insulating substrate 11, release film 1
2. The materials of the conductive paste 14, the conductive powder 15, and the wiring patterns 18 and 19 follow the description of the first embodiment as it is.

As shown in FIG. 5 (f) to FIG. 5 (g), the wiring pattern 1
Of the surface continuity metal layers 31 and 32 formed over the entire surfaces of the wiring layers 8 and 19, the surface layer of the suppression layer parallel to the surface of the insulating base material 11 is polished to adhere only to the end surfaces of the wiring patterns 18 and 19. By exposing the end surface adhering metal layers 31a and 32a to an atmosphere of a reactive gas (not shown) while leaving the metal layers 31a and 32a, the end surface adhering metal layer 3 is formed.
Reacting a reactive gas chemically with 1a, 32a;
Compound layers 41a and 42 are provided on the end faces of wiring patterns 18 and 19, respectively.
a is formed. The compound layers 41a and 42a further adhering to the end surface adhering metal layers 31a and 32a adhering to the end surfaces of the wiring patterns 18 and 19 will be referred to as end surface adhering compound layers 41a and 42a. The end surface adhesive compound layers 41a and 42a are
Is a migration suppressing layer for the end face of the substrate.

Preferable examples of the reactive gas include oxygen, nitrogen, sulfur and the like. In the case of oxygen, the end surface adhering compound layers 41a and 42a are compound layers containing a metal oxide as a main component. In the case of nitrogen, the end face adhesive compound layers 41a and 42a are compound layers containing metal nitride as a main component. In the case of sulfur, the end surface adhering compound layer 41a,
Reference numeral 42a is a compound layer containing metal sulfide as a main component.

In this case, the end surface adhering compound layer 41 is used.
end surfaces adhering metal layers 31a, 32 serving as bases for a, 42a
As for a, nickel, palladium, platinum, zinc, and cadmium, which have better migration resistance and corrosion resistance than copper, which is a constituent material of the wiring patterns 18 and 19, are preferable examples, but it is not necessary to be limited to them. Instead, a metal of another element may be used. Due to oxidation, nitridation, or sulfurization, migration resistance and corrosion resistance are superior to copper which is a constituent material of the wiring patterns 18 and 19.
a, 42a may be formed.

In the above description, the wiring patterns 18 and 19
Surface continuity metal layers 31 and 3 formed over the entire surface of
2, the surface layer of the suppression layer parallel to the surface of the insulating base material 11 is polished to leave the end surface adhering metal layers 31a, 32a only on the end surfaces of the wiring patterns 18, 19, and the end surface adhering metal layers 31a, 31a, Although the reactive gas was caused to react with the reactive gas 32a, the procedure is not necessarily limited to this procedure, and the surface continuous metal layers 31, 32 formed on the entire surfaces of the wiring patterns 18, 19 are exposed to the reactive gas atmosphere. Exposure causes a reactive gas to chemically react with the surface continuity metal layers 31 and 32 on the entire surface thereof, and the wiring patterns 18 and
19, a surface continuity compound layer (not shown) is formed continuously from the surface layer portion parallel to the surface of the insulating base material 11 to the end faces of the wiring patterns 18 and 19, and then the surface continuity compound layer is polished or the like. Insulating base material 11 out of layers
The surface layer portion of the suppression layer parallel to the surface of the wiring pattern is removed, and only the end faces of the wiring patterns 18 and 19 have the end face adhesive compound layers 41a and 41a.
There is also a method of leaving 2a.

In the manner described above, the wiring patterns 18,
In FIG. 19, the end surface adhering compound layer 41 is formed on a surface which is not parallel to the insulating base material 11, that is, the end surfaces of the wiring patterns 18 and 19.
a, 42a, the wiring pattern 18,
Corrosion resistance and migration resistance of copper, which is a material of No. 19, can be improved. As a result, in recent high-density integrated type printed wiring boards, the distance between adjacent wiring patterns is reduced due to the miniaturized wiring. Even if the size is considerably reduced, the printed wiring board can have high insulation reliability.

(Embodiment 4) Embodiment 4 relates to a four-layer wiring board among printed wiring boards. Further, the migration suppressing layer formed on the end face of the wiring pattern is provided with an end face-adhesive organic rust preventive. It forms an agent layer.

FIGS. 6A to 6E are process explanatory sectional views sequentially showing a method of manufacturing a printed wiring board (four-layer wiring board) according to the fourth embodiment.

FIG. 6A shows the printed wiring board A1 in a semi-finished product stage. The semi-finished product printed wiring board A1 is manufactured by the same method as the semi-finished product printed wiring board A1 in the first embodiment.

The structure of the printed wiring board A1 as a semi-finished product will be described. The conductive base material containing the conductive powder 15 filled in the insulating base material 11 and the through holes 13 formed through the upper and lower surfaces of the insulating base material 11 is formed. Paste 14 and insulating base material 11
And wiring patterns 18 and 19 which are attached to the upper and lower surfaces of the conductive paste 15 and are electrically connected to each other via conductive powder 15 in conductive paste 14 filled in the through holes 13. The wiring patterns 18 and 19 are patterned by an etching method or the like.

Further, the above-mentioned semi-finished product printed wiring board A
1 is immersed in the organic rust inhibitor solution 20 or applied or sprayed with the organic rust inhibitor solution in the same manner as shown in FIG.
As shown in (b), wiring pattern 1 on insulating base material 11
Organic rust inhibitor layer 2 with surface continuity over the entire surface of 8, 19
1 and 22 are formed. This surface continuity organic rust inhibitor layer 2
Reference numerals 1 and 22 denote wiring patterns 18 and 1 from the surface layer portions of the wiring patterns 18 and 19 parallel to the surface of the insulating base material 11.
9 are continuous over the end face.

Next, as shown in FIG. 6C, the surface continuous organic rust preventive layers 21 and 22 formed on the entire surfaces of the wiring patterns 18 and 19 are polished by means such as polishing.
Insulating base material 11 of surface continuity organic rust inhibitor layers 21 and 22
The surface layer portion of the suppression layer parallel to the surface of the wiring pattern is removed, and only the end surfaces of the wiring patterns 18 and 19 have the end surface-adhering organic rust inhibitor layer 21
a and 22a.

As described above, a printed wiring board P4 as a double-sided wiring board is obtained.

The end surface-adhering organic rust preventive layers 21a and 22a, which are characteristic components of the fourth embodiment, that is, the end surface-adhering organic rust-preventive layers 21a and 22a adhered to the end surfaces of the wiring patterns 18 and 19, respectively. As the original organic rust inhibitor,
The same applies to the case of the first embodiment, and it is possible to use a rust inhibitor such as an amine or a chromate which is used as a normal rust inhibitor.
Preferred examples of the organic rust inhibitor in the case of (1) are wiring pattern 1
1,2,3 have a high rust-preventive action, that is, a migration-inhibiting action on copper, which is a metal constituting 8,19
-Benzotriazole or a benzotriazole-based compound.

Note that items which have been described in the first embodiment and which will not be described again in the fourth embodiment also apply to the fourth embodiment as they are, and a detailed description thereof will be omitted. In particular, the insulating substrate 11,
Release film 12, conductive paste 14, conductive powder 1
5. Regarding the material of the wiring patterns 18 and 19, the description of the first embodiment is directly followed.

Next, as shown in FIG. 6 (d), the end surfaces of the organic rust preventive layer
The elements shown in FIG. 5C are laminated on both sides of the printed wiring board P4 on which the a and 22a are formed, and copper foil is laminated on both sides of each element to form a heat-compressed laminate. Then, the copper foil is etched by photolithography or the like to perform wiring, thereby obtaining the laminate M1.

Next, as shown in FIG. 6E, the laminate M1 is heated while being compressed in the thickness direction (lamination direction). In the plurality of laminated printed wiring boards P4, each of the insulating base material 11 having compressibility and the conductive powder 15 in the conductive paste 14 filled in each through hole 13 are compressed together, and The wiring patterns 18 and 19 are firmly integrated on the surface of the insulating base material 11. As a result, a printed wiring board (four-layer wiring board) having a multilayer wiring structure, which is the compressed laminate M2, is obtained.

In the manner described above, the printed wiring board P4
Printed wiring board (4
By providing the end surface-adhering organic rust preventive layer 21a as a migration suppressing layer on the end surface of each wiring pattern 18 in the printed wiring board P4 of each layer, the copper Corrosion resistance and migration resistance can be improved. As a result, in printed wiring boards having a high-density and highly integrated multilayer wiring structure, the distance between adjacent wiring patterns is considerably small due to the miniaturized wiring. Even if it is, the printed wiring board having the multilayer wiring structure can have high insulation reliability.

(Embodiment 5) The present embodiment 5 relates to a four-layer wiring board among printed wiring boards.
Further, the formation of the migration suppressing layer on the end face of the wiring pattern is performed simultaneously with the patterning of the wiring pattern.

FIGS. 7A to 7D are process sectional views sequentially showing a method for manufacturing a printed wiring board (four-layer wiring board) according to the fifth embodiment.

Also in the fifth embodiment, the first embodiment
It is assumed that the items described in the above are applicable as they are, and the detailed description is omitted. In particular, insulating substrate 1
1. The materials of the release film 12, the conductive paste 14, the conductive powder 15, and the wiring patterns 18 and 19 follow the description of the first embodiment as it is.

The semi-finished product printed wiring board A0 shown in FIG. 7A is made of an insulating base material 1 in the same manner as in the first embodiment.
1, a through-hole 13 is formed, the through-hole 13 is filled with a conductive paste 14 containing a conductive powder 15, and a release film (not shown) is peeled off. Copper foils 16 and 17 are laminated on both surfaces (this corresponds to FIG. 1D). Starting from the printed wiring board A0 of this semi-finished product, its copper foils 16, 1
7 is etched.

At this time, the copper foils 16 and 17 are patterned by etching using an organic rust inhibitor solution mixed etching solution 50 in which an organic rust inhibitor solution is mixed with an etching solution to be used.

As the organic rust inhibitor solution in this case, there are 1,2,3-benzotriazole or benzotriazole-based compounds similar to those described in the first embodiment. The detailed description of this will follow the description of Embodiment 1 as it is.

Applying or spraying the organic rust inhibitor solution mixed etching solution 50 on the semi-finished product printed wiring board A0, or immersing the semi-finished printed wiring board A0 in the organic rust preventing solution mixed etching solution 50 As a result, FIG.
As shown in (b), the copper foils 16 and 17 are patterned to form wiring patterns 18 and 19, and simultaneously with the formation of the wiring patterns 18 and 19, the wiring patterns 18 and 1 are formed.
On the end face of No. 9, end face adhering organic rust preventive layers 21a and 22a are formed. As described above, the printed wiring board P5 as a double-sided wiring board is obtained.

Next, as shown in FIG. 7 (c), an end surface-adhering organic rust inhibitor layer 21 is formed on the end surfaces of the wiring patterns 18 and 19.
5 (c) are laminated on both sides of the printed wiring board P5 on which the a and 22a are formed, and copper foil is laminated on both sides of each of the elements to form a heat-compressed laminate. Then, the copper foil is etched by photolithography or the like to perform wiring, thereby obtaining the laminate M3.

Next, as shown in FIG. 7D, the laminate M3 is heated while being compressed in the thickness direction (lamination direction). In the plurality of laminated printed wiring boards P5, each of the insulating base material 11 having compressibility and the conductive powder 15 in the conductive paste 14 filled in each through hole 13 are compressed together, and The wiring patterns 18 and 19 are firmly integrated on the surface of the insulating base material 11. As a result, a printed wiring board (four-layer wiring board) having a multilayer wiring structure, which is the compressed laminate M4, is obtained.

In the manner described above, the printed wiring board P5
Printed wiring board (4
By providing the end surface-adhering organic rust preventive layer 21a as a migration suppressing layer on each end surface of the wiring pattern 18 in the printed wiring board P5 of each layer, the copper Corrosion resistance and migration resistance can be improved, and as a result, a printed wiring board having a multilayer wiring structure can have high insulation reliability.

An organic rust inhibitor solution mixed etching solution 5
By using 0, the patterning of the wiring patterns 18 and 19 and the formation of the organic rust preventive agent layers 21a and 22a adhered to the end surfaces are simultaneously performed, so that the productivity can be improved.

(Embodiment 6) Embodiment 6 relates to a four-layered wiring board among printed wiring boards.
Further, the formation of the migration suppressing layer on the end face of the wiring pattern is performed simultaneously with the patterning of the wiring pattern, but prior to the patterning using such an organic rust inhibitor solution mixed etching solution 50. In this method, the printed wiring board A0 as a semi-finished product is compressed and heated to reduce its thickness.

FIGS. 8A to 8E are cross-sectional views for explaining steps in the method of manufacturing a printed wiring board (four-layer wiring board) according to the sixth embodiment.

Also in the sixth embodiment, the first embodiment
It is assumed that the items described in the above are applicable as they are, and the detailed description is omitted. In particular, insulating substrate 1
1. The materials of the release film 12, the conductive paste 14, the conductive powder 15, and the wiring patterns 18 and 19 follow the description of the first embodiment as it is.

The semi-finished product printed wiring board A0 shown in FIG. 8A is made of an insulating base material 1 in the same manner as in the first embodiment.
1, a through-hole 13 is formed, the through-hole 13 is filled with a conductive paste 14 containing a conductive powder 15, and a release film (not shown) is peeled off. Copper foils 16 and 17 are laminated on both surfaces (this corresponds to FIG. 1D). The semi-finished product printed wiring board A0 is used as a starting member.

Next, as shown in FIG. 8B, the above-mentioned semi-finished printed wiring board A0 is heated while being compressed in the thickness direction, to obtain a compressed printed wiring board B0.

Next, the copper foils 16 and 17 are etched. The copper foils 16 and 17 are etched using an organic rust inhibitor solution mixed etching solution 50 in which an organic rust inhibitor solution is mixed with the etching solution used at that time. , 17 are patterned by etching.

As the organic rust inhibitor solution in this case, there are 1,2,3-benzotriazole or benzotriazole-based compounds similar to those described in the first embodiment. The detailed description of this will follow the description of Embodiment 1 as it is.

Applying or spraying the organic rust inhibitor solution mixed etching solution 50 on the semi-finished product printed wiring board B0, or dipping the semi-finished printed wiring board B0 into the organic rust inhibitor solution mixed etching solution 50 As a result, FIG.
As shown in (c), the copper foils 16 and 17 are patterned to form wiring patterns 18 and 19, and simultaneously with the formation of the wiring patterns 18 and 19, the wiring patterns 18 and 1 are formed.
On the end face of No. 9, end face adhering organic rust preventive layers 21a and 22a are formed. In this way, a printed wiring board (double-sided wiring board) P6 in which the end surface-adhering organic rust preventive layers 21a and 22a are formed on the end faces of the wiring patterns 18 and 19 is manufactured.

Next, as shown in FIG. 8D, on the printed wiring board (double-sided wiring board) P6 in the compressed state configured as described above, a second-layer insulating base material 11 is further formed. After laminating the copper foil 16, it is heated while being compressed in the thickness direction (lamination direction), and integrated to obtain a laminate M <b> 5.

Next, as shown in FIG.
5 is coated or sprayed with an organic rust inhibitor solution mixed etching solution 50, or the laminate M5 is immersed in the organic rust inhibitor solution mixed etching solution 50, thereby patterning the copper foil 16 and forming the wiring pattern 18. Then, simultaneously with the formation of the wiring pattern 18, an end surface-adhering organic rust inhibitor layer 21 a is formed on the end surface of the wiring pattern 18. As a result, a laminate M6 in which the end surface-adhering organic rust inhibitor layer 21a is formed on the end surface of the wiring pattern 18 is manufactured.

Next, as shown in FIG.
6, a third layer of the insulating base material 11 and the copper foil 16 are further laminated, and then heated while being compressed in the thickness direction (the laminating direction) to be integrated to obtain a laminated body M7.

Next, as shown in FIG.
7 is coated or sprayed with an organic rust inhibitor solution mixed etching solution 50, or the laminate M7 is immersed in the organic rust inhibitor solution mixed etching solution 50, thereby patterning the copper foil 16 and forming the wiring pattern 18. Then, simultaneously with the formation of the wiring pattern 18, an end surface-adhering organic rust inhibitor layer 21 a is formed on the end surface of the wiring pattern 18. As a result, a printed wiring board (four-layer wiring board) having a multilayer wiring structure in which the end face adhering organic rust inhibitor layer 21a is formed on the end face of the wiring pattern 18 is manufactured.

8 (b) and 8 (d) to 8 (g), each of the compressible insulating base material 11 and the conductive powder in the conductive paste 14 filled in each through hole 13 is used. 15 are compressed together, and the wiring patterns 18 and 19 are firmly integrated on the surface of the insulating base material 11.

In the above, when the surface continuous organic rust preventive layer is formed on the entire surface of the wiring patterns 18 and 19 and may adversely affect the electrical connection, the surface continuity organic rust preventive layer may be used. It is desirable that the surface layer of the suppression layer parallel to the surface of the insulating base material 11 is removed so that the end face-adhering organic rust preventive layers 21a and 22a are left only on the end faces of the wiring patterns 18 and 19.

The wiring patterns 18 and
19, an end surface-adhering organic rust preventive layer 2 on a surface that is not parallel to the insulating base material 11, ie, end surfaces of the wiring patterns 18 and 19.
1a and 22a, the wiring pattern 1
Corrosion resistance and migration resistance of copper, which is the material of Nos. 8 and 19, can be improved. As a result, in recent high-density integrated type printed wiring boards having a four-layer wiring structure, fine copper wiring is required. Even if the distance between adjacent wiring patterns is considerably reduced, a printed wiring board having a four-layer wiring structure can have high insulation reliability.

An organic rust inhibitor solution mixed etching solution 5
By using 0, the patterning of the wiring patterns 18 and 19 and the formation of the organic rust preventive agent layers 21a and 22a adhered to the end surfaces are simultaneously performed, so that the productivity can be improved.

Further, since the printed wiring boards in the compressed state are sequentially laminated, the continuity of the manufacturing process is secured, and the throughput can be improved from this point as well.

In the description of the fourth to sixth embodiments, a printed wiring board having a four-layer wiring structure is taken as an example of a printed wiring board having a multilayer wiring structure. However, it is needless to say that the present invention is not limited to this. The present invention can be applied to a printed wiring board having a three-layer wiring structure or a printed wiring board having a multilayer wiring structure of five or more layers.

The present invention can also be applied to a double-sided wiring board. In that case, the printed wiring board P6 has a form as shown in FIG.

[0140]

Example and Comparative Example (Comparative Example) This comparative example is a conventional method for manufacturing a printed wiring board.

A method for manufacturing a printed wiring board according to this comparative example will be described with reference to FIGS. First, as shown in FIG. 1 (a), a prepreg prepared by impregnating an aromatic polyamide fiber having a release film 12 such as polyethylene terephthalate on both surfaces with an epoxy resin as an insulating base material 11 is prepared. After that, the through holes 13 were formed at predetermined positions by using a laser processing method. Subsequently, as shown in FIG. 1B, the conductive paste 14 was filled in the through holes of the insulating base material 11 using a squeegee or the like. Next, as shown in FIG. 1C, the release film 12 adhered to the insulating base material 11 was peeled off and removed. Then, after laminating the copper foils 16 and 17 on both upper and lower surfaces of the insulating base material 11 and heating the insulating base material 11 and the copper foils 16 and 17 while compressing them along the thickness direction, the insulating base material 11 is heated.
And conductive powder 15 contained in conductive paste 14 and filled in through-hole 13 are both compressed, and copper foils 16 and 17 are adhered on the surface of insulating base material 11. Thus, a printed wiring board A0 as a semi-finished product having a configuration as shown in FIG. 1D was obtained. Then, the copper foils 16 and 17 applied on the surface of the insulating base material 11 are etched to form the wiring patterns 18 and 19.
As shown in FIG. 1 (e), wiring patterns 18, 19 opposed to each other with the insulating base material 11 interposed therebetween via the conductive powder 15 filled in the through holes 13 of the insulating base material 11. A conductive wiring-connected printed wiring board A1, that is, a printed wiring board sample T0 similar to the conventional technique was manufactured.

(Embodiment 1) The present embodiment 1 is a modification of the first embodiment.
This is an embodiment of the present invention. 1 (f) and 1 (g) show a method for manufacturing a printed wiring board according to the first embodiment. The present invention was implemented using the printed wiring board A1 manufactured in the comparative example.

0.2 of 1,2,3-benzotriazole
% Organic solution was prepared. Further, an organic rust inhibitor comprising a 0.2% aqueous solution of 4-methyl-1,2,3-benzotriazole was prepared. Then, FIG.
As shown in Table 1, the printed wiring board A1 was immersed in each of these aqueous solutions at 60 ° C. for several minutes to produce printed wiring board samples T1 and T2.

(Embodiment 2) Embodiment 2 is similar to Embodiment 2
This is an embodiment of the present invention. The present invention was implemented using the printed wiring board A1 manufactured in the comparative example.

Preferable examples of the constituent materials of the end surface adhering metal layers 31a and 32a include nickel, palladium, platinum, zinc, and cadmium. A plurality of printed wiring boards A1 are prepared for each of them. By plating nickel on the wiring patterns of the individual printed wiring boards A1 by electrolytic plating, or individually plating each of palladium, platinum, zinc, and cadmium, five printed wiring board test samples T3. T4
T5, T6, and T7 were produced.

In the above description, the wiring pattern of the printed wiring board test samples T0 to T7 is a comb-shaped surface having a line spacing of 0.318 mm and conforms to the provisions of JIS-Z-3197.

Sample T of Printed Wiring Board Produced in Comparative Example
The insulation resistance of the printed wiring board samples T1 to T6 manufactured in Example 1 and Example 2 was evaluated. In addition, as a condition of the insulation resistance evaluation, each of the above printed wiring board samples was put in an environment of HAST (110 ° C.-85% RH) for 500 hours, and then the insulation resistance was measured. In this measurement, a voltage of 15 V was applied between the comb electrodes. Also, for each printed wiring board sample,
The evaluation was performed every 50 sheets, and those having an insulation resistance value of 10 ⁶ Ω or less were evaluated as defective. However, the insulation resistance value before the injection was 10 ¹² Ω or more in all the printed wiring board samples. Table 1 shows the results of the insulation resistance measurement.

[0148]

[Table 1] As is clear from Table 1, the insulation reliability of each of the printed wiring board samples T1 to T7 according to the present invention is improved as compared with the printed wiring board sample T0 according to the related art.

Although several embodiments have been described above, the present invention can include the following configurations.

(1) At least the wiring patterns 18 and 19
May be applied to a printed wiring board having a multilayer wiring structure, in which the end surface adhering metal layers 31a and 32a are formed on the end surfaces.

(2) At least the wiring patterns 18 and 19
May be applied to a printed wiring board having a multilayer wiring structure as in Embodiment 3 in which the end face adhesive compound layers 41a and 42a are formed on the end faces.

[0152]

According to the present invention for a printed wiring board or a method for manufacturing a printed wiring board, a migration suppressing layer such as an organic rust inhibitor layer, a metal layer, or a compound layer is formed on at least an end face of a wiring pattern. In order to improve the migration resistance of the wiring pattern, high insulation can be achieved even in a high-density integrated type printed wiring board in which the distance between adjacent wiring patterns is considerably reduced due to miniaturized wiring. Reliability can be provided. Further, such a printed wiring board having high insulation reliability can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a process explanatory sectional view sequentially showing a method for manufacturing a printed wiring board (double-sided wiring board) according to a first embodiment of the present invention;

FIG. 2 is a sectional view of a printed wiring board as a product according to the first embodiment of the present invention;

FIG. 3 is a process explanatory sectional view sequentially showing a method for manufacturing a printed wiring board (double-sided wiring board) according to Embodiment 2 of the present invention;

FIG. 4 is a cross-sectional view of a printed wiring board as a product according to a second embodiment of the present invention.

FIG. 5 is a process explanatory sectional view sequentially showing a method for manufacturing a printed wiring board (double-sided wiring board) according to Embodiment 3 of the present invention;

FIG. 6 is a process explanatory sectional view sequentially showing a method of manufacturing a printed wiring board (four-layer wiring board) according to Embodiment 4 of the present invention;

FIG. 7 is a process explanatory sectional view sequentially showing a method of manufacturing a printed wiring board (four-layer wiring board) according to a fifth embodiment of the present invention;

FIG. 8 is a process explanatory sectional view sequentially showing a method for manufacturing a printed wiring board (four-layer wiring board) according to Embodiment 6 of the present invention;

FIG. 9 is a process explanatory sectional view sequentially showing a method of manufacturing a printed wiring board (double-sided wiring board) according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Insulating base material 12 ... Release film 13 ... Through-hole 14 ... Conductive paste 15 ... Conductive powder 16, 17 ... Copper foil 18, 19 ... Wiring pattern 20 ... Organic rust inhibitor solution 21, 22 ... Surface continuity Organic rust preventive layer 21a, 22a: Organic rust preventive layer 31, 32: Surface continuity metal layer 31a, 32a: Metal layer 41a, 42a: Adhesive compound layer 50: Organic rust preventive layer Agent solution mixed etchant

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 1/11 H05K 1/11 N 5E339 3/06 3/06 M 5E343 3/24 3/24 D 5E346 A 3/26 3/26 F 3/40 3/40 K 3/46 3/46 ZN (72) Inventor Takeshi Suzuki 1006 Oojidoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tatsuo Ogawa 1006 Kadoma, Kadoma, Osaka Prefecture F-term (reference) in Matsushita Electric Industrial Co., Ltd. CC01 FF05 GG05 5E317 AA24 BB01 BB11 CC25 CC52 CD01 CD23 CD25 GG09 GG11 5E339 AC01 AD03 BD06 BE13 BE17 CC01 CE12 CE15 CF15 DD02 5E343 AA02 AA07 AA12 BB15 BB22 BB24 BB44 BB47 BB48 BB71 CC22 EE4 2 EE52 EE58 GG14 5E346 AA06 AA11 AA12 AA15 AA22 AA35 AA43 BB01 CC31 CC37 CC46 CC51 CC58 DD32 DD44 EE01 EE06 EE31 FF18 FF35 GG01 GG16 GG17 GG22 GG28 HH08

Claims (21)

[Claims] 1. A printed wiring board having a wiring pattern formed on an insulating base material, wherein a migration suppressing layer is formed on an end face of the wiring pattern. 2. The printed wiring board according to claim 1, wherein the migration suppressing layer is an organic rust preventive layer. 3. The organic rust preventive layer is made of at least one kind of 1,2,3-benzotriazole or a benzotriazole-based compound.
A printed wiring board according to claim 1. 4. The printed wiring board according to claim 1, wherein the migration suppressing layer is a metal layer having better migration resistance than the wiring pattern. 5. The method according to claim 1, wherein the metal layer is nickel, palladium,
The printed wiring board according to claim 4, wherein the printed wiring board is a metal layer made of one or more metals arbitrarily selected from the group consisting of platinum, zinc, and cadmium. 6. The same metal layer is also formed on a surface portion of the wiring pattern parallel to the surface of the insulating base material in a state of being connected to the metal layer as the migration suppressing layer. Claim 4 or Claim 5
A printed wiring board according to claim 1. 7. The method according to claim 1, wherein the migration suppressing layer is a compound layer containing a metal oxide, nitride, or sulfide as a main component, which has better migration resistance than the wiring pattern. Item 2. The printed wiring board according to item 1. 8. The compound layer is an oxide, a nitride, or a sulfide of one or more metals arbitrarily selected from the group consisting of nickel, palladium, platinum, zinc, and cadmium. The printed wiring board according to claim 7, wherein: 9. A through hole is formed in the insulating base material, a conductive paste is filled in the through hole, and a wiring pattern formed on a surface of the insulating base material is joined to the conductive paste. The printed wiring board according to any one of claims 1 to 8, wherein 10. Wiring patterns formed on upper and lower surfaces of the insulating base are electrically connected to each other via conductive powder in a conductive paste filled in through holes formed in the insulating base. The printed wiring board according to any one of claims 1 to 9, wherein a plurality of layers are laminated and integrated to form a multilayer wiring structure. 11. A method for manufacturing a printed wiring board, comprising: a step of forming a wiring pattern on a surface of an insulating base; and a step of forming a migration suppressing layer on an end face of the wiring pattern. 12. The method according to claim 11, wherein the migration suppressing layer is formed on an end face of the wiring pattern by applying or spraying an organic rust inhibitor solution. 13. The print according to claim 11, wherein the migration suppressing layer is formed on an end surface of the wiring pattern by immersing the insulating base material on which the wiring pattern is formed in an organic rust inhibitor solution. Manufacturing method of wiring board. 14. The method according to claim 11, wherein the migration suppressing layer is formed on an end face of the wiring pattern by metal plating. 15. The printed wiring according to claim 11, wherein, after plating the metal, the migration suppressing layer is formed on the end face of the wiring pattern by oxidizing, nitriding or sulphidizing the metal. Plate manufacturing method. 16. The migration suppressing layer according to claim 11, wherein the migration suppressing layer is formed from a surface layer portion of the wiring pattern parallel to a surface of the insulating base material to an end surface of the wiring pattern. 3. The method for producing a printed wiring board according to claim 1. 17. The method according to claim 16, wherein a surface layer of the migration suppressing layer formed on a surface layer of the wiring pattern parallel to a surface of the insulating base material is removed by polishing or the like. Manufacturing method of printed wiring board. 18. A method according to claim 18, further comprising: forming a through hole in the insulating base material, and filling a conductive paste into the through hole, prior to forming a wiring pattern on the surface of the insulating base material. 18. The method according to claim 11, wherein in the step of forming a wiring pattern on the surface of the insulating base material, the wiring pattern is formed in a state of being joined to a conductive paste in the through hole. 3. The method for producing a printed wiring board according to claim 1. 19. A metal foil is laminated on the surface of the insulating base in a state where the metal foil is bonded to the conductive paste, and the insulating base on which the metal foil is laminated is heated while being compressed, so that the metal foil is insulated. 19. The method for manufacturing a printed wiring board according to claim 18, wherein the wiring pattern is formed by applying a photolithography method to the metal foil that has been adhered to a base material and that has been pressed. 20. Wiring patterns formed on upper and lower surfaces of the insulating base are electrically connected to each other via conductive powder in a conductive paste filled in through holes formed in the insulating base. 12. A multilayer wiring structure comprising a plurality of layers laminated and integrated with each other to form a multilayer wiring structure.
9. The method for manufacturing a printed wiring board according to any one of the items up to 9. 21. The method according to claim 11, wherein the patterning of the wiring pattern and the formation of the migration suppressing layer on the end face of the wiring pattern are simultaneously performed by using an etching solution mixed with an organic rust inhibitor solution. 20. The method for manufacturing a printed wiring board according to any one of 20.