JP2013074150A - Wiring board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board in which the connection reliability is enhanced by improving the filling properties of a blind hole, formed by conformal method, with the filled via plating without increasing the material cost or the man-hour, and to provide a manufacturing method therefor.SOLUTION: The wiring board has a blind hole 7 extending from the opening 10 of a surface layer copper foil 3 to an inner layer conductor 5 while penetrating a base material 4, and a filled via 14 which fills the blind hole 7 and connects the inner layer conductor 5 and the surface layer copper foil 3 electrically. The opening 10 of the surface layer copper foil is formed by enlarging the window hole 2 of the surface layer copper foil equal to or larger than the blind hole 7. A manufacturing method therefor is also provided.

Description

  The present invention relates to a wiring board and a manufacturing method thereof, and more particularly, to a wiring board in which interlayer connection is formed by filled via plating and a manufacturing method thereof.

  In recent years, with the demand for higher density, in build-up wiring boards, after forming non-through holes from the surface layer copper foil through the base material to the inner layer copper foil, the non-through holes are filled with filled via plating. Many products that form interlayer connections are produced.

  As a method of forming filled via plating for such interlayer connection, a non-through hole reaching the inner layer conductor is formed by laser processing using a window hole formed in the surface copper foil as a mask (hereinafter referred to as such non-through hole). After the forming method is also referred to as “conformal method”, the copper that has been melted and scattered by laser processing adheres to the periphery of the window hole of the surface copper foil, and a method of removing this by etching is disclosed ( Patent Document 1).

  In the conformal method, a protective metal layer is formed on the surface copper foil, a window hole is formed in both the surface copper foil and the protective metal layer, and laser processing is performed using this as a mask to form a non-through hole. After that, copper melts and scatters on the protective metal layer around the window hole, and the end of the protective metal layer jumps out to the non-through hole side. Therefore, a method of removing the molten scattered copper and the protruding portion by peeling off the protective metal layer is disclosed (Patent Document 2).

  In addition, when formed using the conformal method, the end of the window hole of the surface layer copper foil forms a protruding part that protrudes to the non-through hole side, and this protruding part connects the wiring board using filled via plating. A method for improving reliability is disclosed (Patent Document 3).

JP 2003-046246 A JP 2009-164491 A JP 2010-232590 A

  When an interlayer connection is formed by filled via plating in a non-through hole formed by the conformal method, generally, the end of the window hole 2 of the surface copper foil 3 is formed by laser processing as shown in FIG. The protruding portion 8 is formed by jumping out to the side, but if such a protruding portion 8 is present, the filling property of the filled via plating 14 and the throwing power of the base plating 13 performed before that are hindered. In addition, when the base plating 13 for the filled via plating 14 is performed, a desmear treatment is performed before that, but the inner wall (base material 4) of the non-through hole 7 is etched at that time, so that the surface layer copper The protrusion 8 of the foil 3 tends to expand. For this reason, with the demand for miniaturization of the conductor circuit on the surface layer, the filled via plating 14 and the underlying plating 13 on the surface copper foil 3 are required to be thinner, but the filled via plating 14 and its underlying layer are required. There is a problem that the plating 13 must be thickened to some extent.

  In the method of Patent Document 1, as shown in FIG. 4A, the molten scattered copper adhering to the periphery of the window hole 2 of the surface copper foil 3 is etched after the laser processing, and the opening end 12 is formed in a tapered shape. 5, the case where the protruding portion 8 of the surface copper foil 3 is formed after laser processing is not taken into consideration, and this protruding portion 8 is not removed, and thus has the protruding portion 8 after laser processing. In this case, the protruding portion 8 remains as it is. Even if the protrusion 8 is not provided after the laser processing, the desmear process is performed after etching the molten scattered copper adhering to the periphery of the window hole 2 of the surface layer copper foil 3, so that the non-through-hole 7 is formed in the desmear process. When the inner wall (base material 4) is etched, the surface layer copper foil 3 remaining up to the edge of the non-through hole 7 forms the protruding portion 8, as shown in FIG. Therefore, as a result, there is a problem that the filling property of the filled via plating 14 and the throwing power of the base plating 13 are hindered as in the conventional technique shown in FIG. In the method of Patent Document 2, it is necessary to form a protective metal layer on the surface copper foil, and there is a problem that the material cost and the man-hour are greatly increased. In the method of Patent Document 3, since the protruding portion 8 of the surface layer copper foil 3 is left as it is, the prior art itself shown in FIG. 5 is used. As in Patent Document 1, the fillability of the filled via plating 14 and the underlying plating 13 There is a problem that the throwing power is hindered and the connection reliability cannot be secured.

  The present invention has been made in view of the above-mentioned problems, and while suppressing increase in material cost and man-hours, fillability of filled via plating into non-through holes formed by a conformal construction method and attachment of the underlying plating. Provided are a wiring board and a method for manufacturing the same, which have improved circulation and improved connection reliability.

The present invention is characterized by the following.
1. A desmeared non-through hole penetrating the base material from the opening of the surface layer copper foil to the inner layer conductor, and filling the desmeared non-through hole, electrically connecting the inner layer conductor and the surface layer copper foil A wiring board having filled via plating to be connected, wherein an opening of the surface copper foil is formed to be equal to or larger than the desmeared non-through hole.
2. Item 4. The wiring board according to Item 1, wherein the upper end of the open end of the surface layer copper foil is tapered or curved.
3. A step of forming a window hole in a surface layer copper foil of a wiring board having an inner layer conductor, a substrate and a surface layer copper foil, and through the substrate through the window hole of the surface layer copper foil by laser processing using the window hole as a mask Forming a non-through hole reaching the inner layer conductor, and performing a desmear process, and expanding the window hole of the surface layer copper foil to be equal to or greater than the non-through hole subjected to the desmear process, A method for manufacturing a wiring board, comprising: forming an opening; and forming filled via plating for electrically connecting the inner layer conductor and the surface layer copper foil.
4). Item 4. The method for manufacturing a wiring board according to Item 3, wherein in the step of forming an opening in the surface copper foil, the entire surface of the surface copper foil is soft-etched using a sulfuric acid / hydrogen peroxide aqueous solution, an ammonium persulfate aqueous solution, or a sodium persulfate aqueous solution. .

  According to the present invention, while suppressing an increase in material costs and man-hours, the filling performance of filled via plating into a non-through hole formed by a conformal method and the throwing power of the base plating are improved, and connection reliability is improved. An improved wiring board and a manufacturing method thereof can be provided.

It is sectional drawing of the wiring board which concerns on Example 1 of this invention. It is sectional drawing of the wiring board which concerns on Example 2 of this invention. It is a flowchart showing the manufacturing process of the wiring board of this invention. It is sectional drawing of the conventional wiring board (comparative example 1). It is sectional drawing of the wiring board of another conventional (comparative example 2).

  An embodiment of the wiring board of the present invention is shown in FIGS. This embodiment fills the desmeared non-through hole 7 that penetrates the base material 4 from the opening 10 of the surface layer copper foil 3 and reaches the inner layer conductor 5, and the desmeared non-through hole 7. Wiring having filled via plating 14 for electrically connecting the inner layer conductor 5 and the surface layer copper foil 3, the opening of the surface layer copper foil being enlarged to be equal to or larger than the desmeared non-through hole It is a substrate.

  As shown in FIGS. 3A to 3D, the method for manufacturing a wiring board of the present invention has a window hole in the surface layer copper foil 3 of the wiring board 1 having the inner layer conductor 5, the base material 4, and the surface layer copper foil 3. 3 (FIG. 3 (A)), and the window hole 2 as a mask, the laser beam is used to penetrate the base material 4 from the window hole 2 of the surface layer copper foil 3 and reach the inner layer conductor 5. The step of forming a through hole 7 and performing a desmear process (FIG. 3B), and expanding the window hole 2 of the surface layer copper foil 3 to be equal to or greater than the non-through hole 7 subjected to the desmear process, A step of forming the opening 10 in the copper foil 3 (FIG. 3C), a step of forming the filled via plating 14 for electrically connecting the inner layer conductor 5 and the surface copper foil 3 (FIG. 3D), and Have

  In the present invention, the wiring board refers to one having an inner layer conductor, a base material, and a surface layer copper foil, and includes not only a finished product but also one in the middle of production.

  In this invention, a base material adhere | attaches both, maintaining the insulation between surface layer copper foil and an inner layer conductor. In general, those used for wiring boards can be used, and examples thereof include glass epoxy and glass polyimide having reinforcing fibers, and an epoxy adhesive sheet having no reinforcing fibers. The base material may be an adhesive sheet with a copper foil integrated with a surface layer copper foil. The thickness of the base material is not particularly limited, but when it is 20 μm to 100 μm, when forming a non-through hole with a diameter of 20 μm to 5 mm, particularly 40 to 120 μm suitable for laser processing, fillability of filled via plating and It is desirable in that the throwing power of the base plating can be secured.

  In the present invention, the inner layer conductor refers to a conductor that is located on the opposite side of the surface layer copper foil with the base material interposed therebetween, and the non-through hole reaches from the opening of the surface layer conductor. Since it is a conductor that is located on the opposite side of the surface layer conductor with the base material sandwiched, and the non-through hole reaches from the opening of the surface layer conductor, even if it is an inner layer conductor, the inner layer via the base material is viewed from the surface layer copper foil side Therefore, in the middle stage of production and in the two-layer wiring board, the one that becomes the outer layer conductor is included. The inner layer conductor may be a copper foil alone, or may be one in which plating is formed on the copper foil. Further, the inner layer conductor may be a circuit formed by etching or the like. The thickness of the inner layer conductor needs to be such that it cannot be removed by laser during laser processing or by soft etching when forming an etch back portion described later. In consideration of the accuracy of the inner layer conductor formed in the inner layer, it is desirable that the conductor layer be as thin as possible (for example, 12 to 35 μm) so that the conductor circuit can be formed with a necessary accuracy by etching or the like.

  In the present invention, the surface layer copper foil refers to a copper foil located on the surface layer of the wiring board. This includes not only the surface layer of the wiring board as a finished product, but also the surface layer of the wiring board in the middle of production. As surface layer copper foil, what is generally used for a wiring board, such as electrolytic copper foil and rolled copper foil, can be used. The thickness of the surface copper foil is not particularly limited as long as a window hole having a required diameter can be formed with a required accuracy by etching, and the window hole functions as a mask during laser processing. Considering that the accuracy of the conductor circuit formed on the surface layer is influenced by the thickness of filled via plating described later and the thickness of the underlying plating, it is desirable that the surface layer copper foil be as thin as possible (for example, 3 to 12 μm).

  In the present invention, the window hole functions as a mask during laser processing in a so-called conformal method, and is formed to have a desired size (diameter) by etching the surface layer copper foil. be able to.

  In the present invention, the non-through hole means a hole that penetrates the base material from the opening of the surface layer copper foil to reach the inner layer conductor, and whose bottom is a dead end on the inner layer conductor. Moreover, in this invention, the diameter of a non-through-hole says the diameter of the non-through-hole formed in the base material not including the window hole and opening of surface layer copper foil. It is formed by laser processing using a so-called conformal method. As the laser, a carbon dioxide laser, a UV-YAG laser or the like generally used in a conformal method can be used. The non-through holes formed by laser processing have desmear treatment to ensure adhesion with filled via plating and the underlying plating, which will be described later, and to ensure electrical connection between the inner layer conductor and the surface layer copper foil. Need to do.

  The opening of the surface copper foil is a window hole formed to be a mask for laser processing in the conformal method, and is expanded to be equal to or more than the non-through hole subjected to desmear treatment, and at least the window hole of the surface layer conductor The opening after removing a protrusion part from the edge part. The window hole of surface copper foil is expanded rather than the non-through hole by which the desmear process was carried out, and the opening after forming an etch back part is also included. Here, expanding the window hole of the surface layer copper foil to be equal to or more than the non-through hole subjected to desmear treatment means that the diameter of the window hole of the surface layer copper foil is larger than the diameter of the non-through hole formed in the substrate. This means that the diameter is equal to or greater than that. A protrusion part is an edge part of the window hole of surface layer copper foil, Comprising: The part which protruded in the shape of an eaves into the inner side of the non-through-hole formed in the base material is said.

  Thus, in this invention, as shown in FIG.3 (C), the window hole 2 of the surface layer copper foil 3 is expanded and formed more than equivalent to the non-through-hole 7 after already performing a desmear process. The That is, unlike the prior art shown in FIG. 4, the desmear process is not performed after the window hole 2 of the surface layer copper foil 3 is enlarged to the same extent as the non-through hole 7, but as shown in FIG. Then, after the desmear treatment, the window hole 2 of the surface layer copper foil 3 is enlarged to be equal to or larger than the non-through hole 7. For this reason, the surface layer copper foil 3 does not jump out to the inside of the non-through hole 7 at the entrance of the non-through hole 7 subjected to the desmear process and form the protruding portion 8. Therefore, even if the non-through hole 7 is as fine as 20 to 5 mm in diameter, particularly 40 to 120 μm suitable for laser processing, the liquid flow of the plating solution used for the filled via plating 14 and the underlying plating 13 becomes smooth, and the filled via The filling property of the plating 14 and the throwing power of the base plating 13 are improved. In addition, since the protruding portion 8 of the surface copper foil 3 does not exist at the entrance of the non-through hole 7, the current concentration near the entrance is small. Therefore, the filling property of filled via plating 14 into the non-through hole 7 (embedding property of the non-through hole 7 by plating) is improved. Further, after the desmear treatment, when the window hole 2 of the surface layer copper foil 3 is enlarged larger than the non-through hole 7 and the etch-back portion 11 is formed, the entrance of the non-through hole 7 is widened, so that filled via plating is performed. 14 and the throwing power of the base plating 13 are improved.

  In the present invention, the etch-back portion refers to a portion formed on the base material around the non-through hole, in which the window hole of the surface layer copper foil is enlarged from the non-through hole. That is, the opening edge part of surface copper foil points out on the base material exposed from surface copper foil by retreating outside the edge part of a non-through-hole. The etch back portion is formed so as to surround the entire periphery of the non-through hole.

  In order for the opening of the surface copper foil to be formed to be equal to or larger than the non-through hole subjected to the desmear treatment, a method of removing the edge of the window hole of the surface copper foil by etching can be used. . Specifically, there is a method in which the entire wiring board is immersed in a soft etching solution and the entire surface of the surface copper foil is soft etched. Etching when immersed in a soft etchant tends to proceed faster at the edge of the surface copper foil, so priority is given to the edge (projection) of the window hole of the surface copper foil protruding to the non-through hole side. Therefore, the opening of the surface layer copper foil can be enlarged to be equal to or larger than the desmeared non-through hole. Furthermore, it is easy to form an etchback portion on the substrate. For this reason, as shown in FIGS. 1 and 2, the cross-sectional shape of the opening end 12 of the surface copper foil 3 becomes a smooth taper or a curved shape, so that the plating solution used for the filled via plating 14 and the underlying plating 13 is not used. The liquid flow becomes smooth, and the filling property of the filled via plating 14 and the throwing power of the base plating 13 are improved. Moreover, since the protrusion part 8 of the surface layer copper foil 3 does not exist in the opening edge part 12 of the surface layer copper foil 3, there is also little concentration of the electric current to entrance vicinity. Therefore, the filling property of the filled via plating 14 into the non-through hole 7 is improved. As the soft etching solution, a known soft etching solution such as a sulfuric acid / hydrogen peroxide aqueous solution, an ammonium persulfate aqueous solution, or a sodium persulfate aqueous solution can be used. Thus, the formation of the opening 10 in the surface layer copper foil 3 can be easily performed only by managing the etching amount using a known soft etching solution used in the manufacturing process of the wiring board 1, so that the material cost is reduced. And increase in man-hours.

  In the present invention, filled via plating refers to plating formed to fill non-through holes. Filled via plating used in general wiring boards can be used, and examples thereof include a copper sulfate electroplating solution added with an additive. The thickness of the filled via plating is set to a thickness that can fill the non-through holes, but it is preferably 3 to 12 μm on the surface layer copper foil in consideration of the accuracy of the conductor circuit formed on the surface layer.

  In the present invention, filled via plating is formed so as to fill non-through holes and to electrically connect the inner layer conductor and the surface layer copper foil. That is, the filled via plating is filled not only in the non-through hole but also in the entire surface including the opening of the surface layer copper foil formed on the substrate. As a result, even if the non-through hole is 20 μm to 5 mm in diameter, particularly 40 to 120 μm suitable for laser processing and fine, the generation of voids in filled via plating can be suppressed, and connection reliability can be improved. Can be improved.

  The ground plating of filled via plating is formed from the surface of the surface copper foil to the inside of the non-through hole, and serves as a power feeding layer for forming filled via plating by electroplating. It can form using electroless copper plating etc. which are generally used in the manufacturing process of a wiring board. The thickness of the base plating is preferably 0.1 to 1 μm in consideration of the accuracy of the conductor circuit formed on the surface layer.

  Examples of the present invention will be described below, but the present invention is not limited to the examples.

Example 1
A substrate (thickness 60 μm, GEN-E-679FG, manufactured by Hitachi Chemical Co., Ltd., trade name) is sandwiched between an inner layer conductor formed by copper foil and copper plating, and an insulating resin layer made of glass epoxy. A wiring board on which a surface layer copper foil having a thickness of 18 μm was bonded was prepared. An etching resist was formed on the surface layer copper foil 3 of the wiring board 1, and a window hole 2 having a diameter of 80 mm was formed by etching (FIG. 3A).

  Using the window hole 2 of the surface layer copper foil 3 of the wiring substrate 1 as a mask, a non-through hole 7 that penetrates the base material 4 from the window hole 2 of the surface layer copper foil 3 to the inner layer conductor 5 by laser processing is formed. Smear removal by sodium permanganate treatment was performed (FIG. 3B). At this time, the non-through hole 7 had a diameter of 110 μm, and a protrusion 8 having a diameter of about 15 μm was formed on one side.

  Next, the entire wiring board 1 was immersed in a soft etching solution, and the entire surface of the surface layer copper foil 3 was soft etched. Thereby, while removing the protrusion part 8 formed in the edge part of the window hole 2 of the surface layer copper foil 3 by etching, the window hole 2 of the surface layer copper foil 3 is expanded to the same extent as the non-through-hole 7, and surface layer copper foil 3 openings 10 were formed (FIG. 3C). That is, the tip of the open end 12 of the surface layer copper foil 3 is located at the upper end of the non-through hole 7. The soft etching solution used at this time is a sodium persulfate aqueous solution (150 g / L) used in the pretreatment process for the base plating. Thereby, as shown in FIG.3 (C), the cross-sectional shape of the opening edge part 12 of the surface layer copper foil 3 became a smooth taper or curve shape.

  Next, base plating for filled via plating was performed using CUST-2000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) which is an electroless copper plating solution. The thickness of the base plating at this time was set to be relatively thin at about 0.6 μm, but the throwing power could be secured.

  Next, filled via plating 14 is formed so as to fill non-through-holes 7 by electroplating using top lutina NSV (trade name, manufactured by Okuno Seiyaku Co., Ltd.), which is a filled via plating solution, using base plating 13 as a feeding layer. (FIG. 3D). At this time, the thickness of the filled via plating 14 was set to a relatively thin value of about 13 μm on the surface layer copper foil 3, but the filling property of the non-through holes 7 could be secured.

(Example 2)
The step of forming window holes 2 in the surface layer copper foil 3 of the wiring board 1 having the inner layer conductor 5, the base material 4 and the surface layer copper foil 3 (FIG. 3A), and laser processing using the window hole 2 as a mask From the window hole 2 of the surface layer copper foil 3 through the base material 4 to the inner layer conductor 5, a non-through hole 7 is formed, and until the step of performing the desmear process (FIG. 3B), Example 1 and The same was done. The non-through hole 7 at this time has a diameter of 130 μm, and a protruding portion 8 of about 15 μm is formed on one side.

  Next, the entire wiring board 1 was immersed in a soft etching solution, and the entire surface of the surface layer copper foil 3 was soft etched. Thereby, while removing the protrusion part 8 formed in the edge part of the window hole 2 of the surface layer copper foil 3 by etching, the window hole 2 of the surface layer copper foil 3 is expanded rather than the non-through hole 7, An etch-back portion 11 was formed on the surrounding base material 4 (FIG. 3C). That is, in the etch-back part 11, the surface of the base material 4 around the non-through hole 7 is exposed. The soft etching solution used at this time is a sodium persulfate aqueous solution (150 g / L) used in the pretreatment process for the base plating and the like, and the etchback amount (etchback portion width) is 10 μm. Thereby, as shown in FIG.3 (C), the cross-sectional shape of the opening edge part 12 of the surface layer copper foil 3 became a smooth taper or curve shape.

  Next, base plating for filled via plating was performed using CUST2000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) which is an electroless copper plating solution. The thickness of the base plating at this time was set to be relatively thin at about 0.3 μm, but the throwing power could be secured.

  Next, filled via plating 14 is formed so as to fill non-through-holes 7 by electroplating using top lutina NSV (trade name, manufactured by Okuno Seiyaku Co., Ltd.), which is a filled via plating solution, using base plating 13 as a feeding layer. (FIG. 2). At this time, the thickness of the filled via plating 14 was set to a relatively thin value of about 10 μm on the surface layer copper foil 3, but the filling property of the non-through holes 7 could be secured.

(Comparative Example 1)
The step of forming window holes 2 in the surface layer copper foil 3 of the wiring board 1 having the inner layer conductor 5, the base material 4 and the surface layer copper foil 3 (FIG. 3A), and laser processing using the window hole 2 as a mask From the window hole 2 of the surface layer copper foil 3 to the step of forming the non-through hole 7 that penetrates the base material 4 and reaches the inner layer conductor 5, the same process as in Example 1 was performed, but the desmear treatment was not performed. . The non-through hole 7 at this time has a diameter of 100 μm, and a protruding portion 8 of about 10 μm is formed on one side.

  Next, in the same manner as in Example 1, the entire wiring board 1 was immersed in a soft etching solution, and the entire surface of the surface layer copper foil 3 was soft etched. Thereby, while removing the protrusion part 8 formed in the edge part of the window hole 2 of the surface layer copper foil 3 by etching, the window hole 2 of the surface layer copper foil 3 is expanded to the same extent as the non-through-hole 7, and surface layer copper foil 3 openings 10 were formed (FIG. 4A). That is, the tip of the open end 12 of the surface layer copper foil 3 is located at the upper end of the non-through hole 7. The soft etching solution used at this time is a sodium persulfate aqueous solution (150 g / L) used in the base plating pretreatment step and the like, and the etch back amount (width of the etch back portion 11) is 0 μm.

  Next, smear removal by sodium permanganate treatment was performed. By this desmear process, the base material 4 at the end of the non-through hole 7 is etched, and the end of the surface layer copper foil 3 jumps out to the inside of the non-through hole 7 by about 5 to 10 μm, thereby forming the protrusion 8 ( FIG. 4 (B)). Next, base plating 13 for filled via plating 14 was performed using CUST2000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) which is an electroless copper plating solution. At this time, the thickness of the base plating 13 was thicker than those in Examples 1 and 2, and by setting the thickness to about 1.5 μm, the throwing power could be secured.

  Next, filled via plating was formed so as to fill non-through holes by electroplating, using the top lutina NSV (trade name, manufactured by Okuno Seiyaku Co., Ltd.), which is a filled via plating solution, using the base plating as a power supply layer (illustration). do not do.). By the desmear treatment, the surface copper foil has protrusions, so the filled via plating thickness is thicker than in Examples 1 and 2 and is set to be relatively thick at about 15 μm on the surface copper foil. , Generation of voids was observed.

(Comparative Example 2)
The step of forming window holes 2 in the surface layer copper foil 3 of the wiring board 1 having the inner layer conductor 5, the base material 4 and the surface layer copper foil 3 (FIG. 3A), and laser processing using the window hole 2 as a mask Thus, the process was performed in the same manner as in Example 1 until the step of forming the non-through hole 7 that penetrates the base material 4 from the window hole 2 of the surface layer copper foil 3 and reaches the inner layer conductor 5 (FIG. 3B). The non-through hole 7 at this time has a diameter of 100 μm, and a protruding portion 8 of about 10 μm is formed on one side, but the protruding portion 8 of the surface layer copper foil 3 is left.

  Next, smear removal by sodium permanganate treatment was performed, and base plating for filled via plating was performed using CUST2000 (trade name, manufactured by Hitachi Chemical Co., Ltd.) which is an electroless copper plating solution. The thickness of the base plating at this time is thicker than those of Examples 1 and 2, and is set to about 3.0 μm, thereby ensuring throwing power.

  Next, filled via plating 14 is formed so as to fill non-through-holes 7 by electroplating using top lutina NSV (trade name, manufactured by Okuno Seiyaku Co., Ltd.), which is a filled via plating solution, using base plating 13 as a feeding layer. (FIG. 5). At this time, the thickness of the filled via plating 14 was set to be relatively thick as about 20 μm on the surface copper foil 3 than in Examples 1 and 2, but the filling property of the non-through holes 7 could not be ensured, Occurrence was seen.

1. 1. Wiring board 2. Window hole Surface copper foil 4. Base material 5. 5. Inner layer conductor Void 7. Non-through hole 8. Projection 9 Recess 10. Opening 11. Etch back section 12. Open end 13. Base plating14. Filled via plating

Claims (4)

  A desmeared non-through hole penetrating the base material from the opening of the surface layer copper foil to the inner layer conductor, and filling the desmeared non-through hole, electrically connecting the inner layer conductor and the surface layer copper foil A wiring board having filled via plating to be connected, wherein an opening of the surface copper foil is formed to be equal to or larger than the desmeared non-through hole.   The wiring board according to claim 1, wherein the opening end portion of the surface layer copper foil is tapered or curved. Forming a window hole in a surface layer copper foil of a wiring board having an inner layer conductor, a base material, and a surface layer copper foil;
Using the window hole as a mask, by laser processing, forming a non-through hole penetrating the base material from the window hole of the surface layer copper foil to the inner layer conductor, and performing a desmear treatment;
Expanding the window hole of the surface copper foil to be equal to or more than the desmeared non-through hole, and forming an opening in the surface copper foil;
A method for manufacturing a wiring board, comprising: forming a filled via plating that electrically connects the inner layer conductor and the surface layer copper foil.   4. The method of manufacturing a wiring board according to claim 3, wherein in the step of forming the opening in the surface copper foil, the entire surface of the surface copper foil is soft-etched using a sulfuric acid / hydrogen peroxide aqueous solution, an ammonium persulfate aqueous solution, or a sodium persulfate aqueous solution. Method.

Images