JP2003133725A - Method for manufacturing wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a wiring board capable of patterning a wiring layer from a conductive layer without generating any problem concerning a base layer having a conductive layer on the base layer surface and a through-hole conductor packed with a resin packing body. SOLUTION: This method for manufacturing a wiring board 1 is provided with a process for perforating a through-hole 9 in a base layer 6 and a process for forming a conductive layer 37 on a base layer surface 35 by carrying out plating, and for forming a through-hole conductor 11 in the through-hole 9. Also, this method is provided with a process for forming a resin packing body 13 in the through-hole conductor 11 and a process for removing an expanding part 13b of the resin packing body 13. Also, this method is provided with a process for thinning the thickness of the conductive layer 37 of the base layer surface 35. Then, the thinned conductive layer 37 is patterned so that a wiring layer can be formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a wiring board having a wiring layer formed by patterning a conductor layer, and in particular, having a through-hole conductor extending to the above-mentioned conductor layer. The present invention relates to a method for manufacturing a wiring board filled with a resin filling body.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a wiring board, a wiring layer is often formed by patterning a conductor layer such as a Cu layer formed on the surface of a base layer.
Specifically, an etching resist layer having a predetermined pattern corresponding to the pattern of the wiring layer is formed on the conductor layer on the surface of the base layer. Then, the conductor layer exposed from the resist layer is removed by etching to form a wiring layer. However, if the conductor layer to be etched is thick, the etching tends to be insufficient, and the conductor layer to be removed may not be completely removed and may remain on the surface of the base layer. As a result, a short circuit may occur in the wiring layer. Further, since the etching progresses not only in the thickness direction but also in the horizontal direction perpendicular to the thickness direction, the conductor layer covered with the etching resist layer is also removed by etching, and the wiring is easily thinned. In particular, this phenomenon becomes prominent when the conductor layer to be etched is thick. Therefore, if a fine pattern is formed, there is a risk that the wiring layer may be opened.

On the other hand, conventionally, the following measures have been proposed. That is, the conductor foil on the surface of the base layer is reduced in thickness by chemical etching or the like, and then the thinned conductor foil is subjected to patterning. If the conductor foil is thinned in advance before patterning as described above, it is possible to solve the above-mentioned problem that the conductor remains between the wiring and the problem that the wiring is thinned.

[0004]

By the way, in the prior art,
After reducing the thickness of the conductor foil on the surface of the base layer, holes and the like are formed in the base layer. This is because if the thickness of the conductor foil is made thin, the burden of punching can be reduced. For this reason,
When forming a through-hole conductor in the base layer, first, reduce the thickness of the conductor foil on the surface of the base layer, then punch a through-hole in the base layer, and then form a through-hole conductor by plating. , The inside of which is filled with a resin filling body. Then, the conductor layer on the surface of the base layer is patterned to form a wiring layer.

However, when a wiring board is manufactured by such a method, the through-hole conductor is formed only by plating, whereas the conductor layer on the surface of the base layer is a conductor foil.
The through-hole conductor is formed, and the plated layer is formed on the conductor foil. That is, the conductor layer on the surface of the base layer is thicker than the thickness of the through-hole conductor. Therefore, the thickness of the through-hole conductor and the thickness of the base layer surface cannot be freely determined independently. In addition, the above-mentioned problems occur. That is, when patterned, the conductor layer on the surface of the base layer is likely to be insufficiently etched, and the conductor may remain on the surface of the base layer. As a result, a short circuit may occur in the wiring layer. Further, the etching progresses in the horizontal direction, and the conductor layer covered with the etching resist layer is also removed by the etching, so that the wiring is likely to be thinned. As a result, there is a risk of causing an open in the wiring layer, making it difficult to form fine wiring. On the other hand, if the plating layer is formed thin in order to thin the conductor layer on the surface of the substrate, the through-hole conductor formed together becomes too thin, which may cause a defect such as poor conduction in the through-hole conductor.

Further, when manufacturing a wiring board having a through-hole conductor, the following problems may occur. That is, a conductor layer (sometimes referred to as a lid plating layer) may be further formed on the through-hole conductor and the end surface of the resin filling body. For example, when it is desired to directly connect a via conductor or the like on the through-hole conductor. When the lid plating layer is formed, the conductor layer of the portion of the base layer surface other than on the resin filler is added to the original conductor layer and the plating layer formed at the same time as the lid plating layer later. Get thicker. On the other hand, since the conductor layer on the resin filling body is only the lid plating layer, it is thinner than the surrounding conductor layers. Therefore, if the conductor layer is thinned immediately before patterning these conductor layers, if a thick conductor layer other than on the resin filling body is thinned, the lid plating layer on the resin filling body is thinned. Is almost gone. On the contrary, if it is attempted to secure a certain thickness of the lid plating layer, the conductor layer in the thick portion can hardly be thinned, and as a result, the problem that the conductor remains between the above wirings during patterning and wiring The problem of thinning is likely to occur.

The present invention has been made in view of the above circumstances, and has a conductor layer on the surface of the base layer, and a base layer having a through-hole conductor filled with a resin filling material, and further a resin filling material and the like. It is an object of the present invention to provide a method for manufacturing a wiring board, which allows a wiring layer to be patterned from a conductor layer without causing the above-mentioned problems with respect to a base layer on which a conductor layer (cover plating layer) is formed.

[0008]

[Means for Solving the Problems, Actions and Effects] The means for solving the problems are a through hole forming step of forming a through hole in a base layer, a plating process to form a conductor layer on the surface of the base layer, and the through hole. A plating step of forming a through-hole conductor on the inner wall surface of the resin, a resin-filling body forming step of forming a resin filling body in the through-hole conductor, and a portion of the resin filling body bulging from the base layer surface is removed. A removing step; a conductor layer thinning step after the removing step to reduce the thickness of the conductor layer on the surface of the base layer; and a patterning step to pattern the thinned conductor layer to form a wiring layer. It is a manufacturing method.

In the present invention, the through-hole conductor is formed on the base layer, and the resin filling body is further formed on the base layer, and then the conductor layer is thinned before patterning. If manufactured in this way, the through-hole conductor can have a sufficient thickness. Therefore, it is possible to prevent problems such as poor conduction due to the thinned through-hole conductor. on the other hand,
The thickness of the conductor layer on the surface of the base layer can be made sufficiently thin independently of the thickness of the through-hole conductor, that is, in the state where the thickness of the through-hole conductor is sufficiently secured. For this reason,
In the patterning process, the wiring layer can be formed reliably and accurately. That is, since the etching is insufficient, the conductor layer to be removed is not completely removed and does not remain on the surface of the base layer. Therefore, a short circuit is unlikely to occur in the wiring layer. Further, the etching progresses not only in the thickness direction but also in the horizontal direction perpendicular to the thickness direction, and the conductor layer covered with the etching resist layer is also removed by etching, but the conductor layer to be etched is sufficiently thin. It is possible to minimize this gouging. Therefore, it is possible to prevent the wiring from being thinned, and even if a fine wiring pattern is formed, the wiring layer is unlikely to be opened.

In the present specification, the base layer refers to a substrate which is obtained in the process of manufacturing a core substrate or a wiring substrate and forms through holes penetrating between the front and back surfaces thereof. For example, a core substrate including one resin insulating layer can be used. Further, it may be a copper clad core substrate in which a copper foil is attached to the core substrate.
Further, for example, a laminated substrate in which a plurality of resin insulating layers and wiring layers are alternately laminated can be cited.

In the through hole forming step, any method may be used as long as the through hole can be formed in the base layer. For example, there is a method of forming a through hole with a drill or a laser. In the plating step, any method may be used as long as the conductor layer on the surface of the base layer and the through-hole conductor can be formed. Generally, it is formed by performing electroless plating and then electrolytic plating.

In the resin filling body forming step, any method may be used as long as the resin filling body can be formed in the through-hole conductor. For example, by using a mask having a predetermined pattern having through holes corresponding to the positions and openings of the through-hole conductors, the resin paste is printed and filled in the through-hole conductors, and then the resin paste is cured by heat. Examples include methods of forming the body. In the removing step, any method may be used as long as it is possible to remove the portion of the resin filling body that bulges from the surface of the base layer. For example, a method of removing by mechanical polishing such as belt sander polishing or buff polishing may be used. In addition, it is difficult to form such a resin filling body from the beginning so that the end surface of the resin filling body is flush with the base layer surface from the beginning, so that a part of the resin filling body is formed into the base layer. This is because it is necessary to form the resin filling body in a larger size so as to bulge from the surface.

In the conductor layer thinning step, any method may be used as long as the thickness of the conductor layer on the surface of the base layer can be reduced. For example, there is a method of thinning the conductor layer by chemical etching or mechanical polishing. The conductor layer may have a thickness after thinning so that the wiring layer can be reliably and accurately formed in the subsequent patterning step.
In the patterning step, any method may be used as long as the thinned conductor layer can be patterned to form the wiring layer. For example, an etching resist layer having a predetermined pattern corresponding to the pattern of the wiring layer is formed on the conductor layer. Then, the conductor layer exposed from this resist layer is removed by etching, and then the resist layer is peeled off,
A method of forming a wiring layer may be used.

Further, in the above method of manufacturing a wiring board, a surface conductor layer is previously formed on the surface of the base layer used in the through hole forming step, and the conductor layer formed in the plating step is It is preferable to provide a method of manufacturing a wiring board including the surface conductor layer and a plating layer formed on the surface conductor layer by plating.

When the surface conductor layer is previously formed on the surface of the base layer, the plating step increases the thickness of the conductor layer because the thickness of the plated layer is added to the surface conductor layer. For this reason, during patterning, the above-mentioned problem of a conductor remaining between wirings and the problem of thinning wirings are particularly likely to occur.

However, according to the present invention, since the through-hole conductor or the like is first formed in the base layer and then the conductor layer thinning step is performed before the patterning step to thin the conductor layer, the through-hole conductor is sufficiently formed. On the other hand, the thickness of the conductor layer on the surface of the base layer can be made sufficiently thin independently of the thickness of the through-hole conductor. Therefore, the wiring layer can be formed reliably and accurately in the patterning step. That is, since the etching is insufficient, the conductor layer to be removed is not completely removed and does not remain on the surface of the base layer. Therefore, a short circuit is unlikely to occur in the wiring layer. Further, it is possible to minimize the hollowing of the conductor layer in the horizontal direction due to etching. Therefore, it is possible to prevent the wiring from being thinned, and even if a fine wiring pattern is formed, the wiring layer is unlikely to be opened.

Further, in the method for manufacturing a wiring board according to any one of the above, the conductor layer thinning step is a step of thinning the thickness of the conductor layer on the surface of the base layer by etching. After the forming step and before the patterning step, the wiring board manufacturing method may also include a second removing step of removing a portion of the resin filling body protruding from the base layer surface by the conductor layer thinning step.

According to the present invention, in the conductor layer thinning step, the conductor layer is thinned by etching. Further, after this step and before the patterning step, there is also provided a second removing step of removing a portion of the resin filling body protruding from the base layer surface by the conductor layer thinning step. Generally, since the surface of the base layer has undulations, it is difficult to uniformly thin the conductor layer by mechanical polishing or the like. On the other hand, if the conductor layer is thinned by etching as in the present invention, the conductor layer can be easily and uniformly thinned.

However, when the conductor layer thinning step is performed by etching, the entire conductor layer can be uniformly etched, but the resin filling body is not etched. As a result, the end portion of the resin filling body is not etched. It is in a state of protruding from the conductor layer (base layer surface). If a resin insulating layer is newly laminated on the base layer in this state, unevenness may occur on the surface of the resin insulating layer and the flatness of the surface may be impaired. However, in the present invention, in the second removing step, the portion of the resin filler protruding from the base layer surface is removed by the conductor layer thinning step, and the end face of the resin filler is flush with the base layer surface. Therefore, the surface of the resin insulating layer can be made flat even if a new resin insulating layer is laminated on the base layer in the subsequent step.

Another solution is a through hole forming step of forming a through hole in a base layer, plating is performed to form a first conductor layer on the surface of the base layer, and a through hole conductor is formed on the inner wall surface of the through hole. A first plating step for forming a resin filling body, a resin filling body forming step for forming a resin filling body in the through-hole conductor, a removing step for removing a portion of the resin filling body bulging from the surface of the base layer, After the removing step, a conductor layer thinning step of reducing the thickness of the first conductor layer on the surface of the base layer, and after the conductor layer thinning step, plating is performed again to form a second layer on the surface of the base layer including on the resin filling body. A method of manufacturing a wiring board, comprising: a second plating step of forming a conductor layer; and a patterning step of patterning a conductor layer including the first conductor layer and the second conductor layer to form a wiring layer.

According to the present invention, not only is the conductor layer thinning step performed prior to the patterning step,
It is performed before the second plating step. If the second plating step is performed before the conductor layer thinning step, as described in the problem to be solved, the conductor layer on the portion other than on the resin filling body becomes thicker, while the conductor on the resin filling body is thickened. The layers do not get thick. Therefore, when the conductor layer thinning step is performed thereafter, if the conductor layer in the thick portion is to be thinned, there is a possibility that the conductor layer on the resin filling body is almost lost. On the contrary, if it is attempted to secure a certain thickness of the conductor layer on the resin-filled body, the conductor layer in the thick portion can hardly be thinned, and as a result, the conductor remains between the wirings during patterning. And the problem that wiring becomes thin occurs.

On the other hand, in the present invention, as described above,
Since the conductor layer thinning step is performed before the second plating step, the thickness of the conductor layer on the base layer surface can be sufficiently reduced without reducing the thickness of the conductor layer (second conductor layer) on the resin filling body. can do. Therefore, in the patterning step, the wiring layer can be formed reliably and accurately. That is,
Due to insufficient etching, the conductor layer to be removed is not completely removed and does not remain on the surface of the base layer. Therefore, a short circuit is unlikely to occur in the wiring layer. Further, it is possible to minimize the hollowing of the conductor layer in the horizontal direction due to etching. Therefore, it is possible to prevent the wiring from being thinned, and even if a fine wiring pattern is formed, the wiring layer is unlikely to be opened.

Further, in the present invention, the through-hole conductor and the resin filling body are first formed in the base layer, and thereafter, the conductor layer thinning step is performed, and then the second plating step and the patterning step are performed. If manufactured in this way, the through-hole conductor can have a sufficient thickness. Therefore, it is possible to prevent problems such as poor conduction due to the thinned through-hole conductor. On the other hand, the thickness of the first conductor layer can be made sufficiently thin in consideration of the formation of the second conductor layer later, and independently of the thickness of the through-hole conductor. Therefore, even if the second conductor layer is added, the thickness of the entire conductor layer can be made sufficiently thin. Furthermore, the second
Since the conductor layer is formed after the conductor layer thinning step, it can be formed to have a sufficient thickness.

The through hole forming step, the first and second steps
The plating process, the resin filling body forming process, the removing process, the conductor layer thinning process, and the patterning process are as described above. Further, the second plating step is performed again by forming the second conductor layer (cover plating layer) on the resin-filled body so that the via conductor or the like can be directly connected to the through-hole conductor. Because it will be. Such a form may be referred to as Via on PTH. Via-on-PTH is a form that is often seen at present when the pitch of wirings is becoming narrower due to the miniaturization of wiring boards.

Further, in the above-mentioned wiring board manufacturing method, a surface conductor layer is previously formed on the surface of the base layer used in the through hole forming step, and the first conductor formed in the plating step is formed. The layer is preferably a method of manufacturing a wiring board including the surface conductor layer and a plated layer formed on the surface conductor layer by plating.

When the surface conductor layer is previously formed on the surface of the base layer, the plating step causes the thickness of the plated layer to be added to the surface conductor layer, so that the thickness of the conductor layer becomes particularly thick. For this reason, during patterning, the above-mentioned problem of a conductor remaining between wirings and the problem of thinning wirings are particularly likely to occur.

However, in the present invention, the through-hole conductor or the like is formed on the base layer first, and then the conductor layer thinning step is performed before the second plating step to thin the conductor layer.
While making the thickness of the through-hole conductor sufficient, the thickness of the conductor layer on the surface of the base layer can be made sufficiently thin independently of the thickness of the through-hole conductor. Therefore, the wiring layer can be formed reliably and accurately in the patterning step. That is, since the etching is insufficient, the conductor layer to be removed is not completely removed and does not remain on the surface of the base layer. Therefore, a short circuit is unlikely to occur in the wiring layer. Further, it is possible to minimize the hollowing of the conductor layer in the horizontal direction due to etching. Therefore, it is possible to prevent the wiring from being thinned, and even if a fine wiring pattern is formed, the wiring layer is unlikely to be opened.

Furthermore, in the method for manufacturing a wiring board according to any one of the above, the conductor layer thinning step is a step of thinning the thickness of the first conductor layer on the surface of the base layer by etching. After the layer thinning step and before the second plating step, a method for manufacturing a wiring board, which also includes a second removing step of removing a portion of the resin filling body protruding from the base layer surface by the conductor layer thinning step. Good to do.

According to the present invention, in the conductor layer thinning step, the thickness of the conductor layer is reduced by etching. Further, after this step and before the second plating step, there is also provided a second removing step of removing a portion of the resin filler protruding from the base layer surface by the conductor layer thinning step. Generally, since the surface of the base layer has undulations, it is difficult to uniformly thin the conductor layer by mechanical polishing or the like. On the other hand, if the conductor layer is thinned by etching as in the present invention, the conductor layer can be easily and uniformly thinned.

However, if the conductor layer thinning step is performed by etching, the entire conductor layer can be uniformly etched, but the resin filling body is not etched. As a result, the end portion of the resin filling body is not etched. It is in a state of protruding from the conductor layer (base layer surface). If a resin insulating layer is newly laminated on the base layer in this state, unevenness may occur on the surface of the resin insulating layer and the flatness of the surface may be impaired. However, in the present invention, in the second removing step, the portion of the resin filler protruding from the base layer surface is removed by the conductor layer thinning step, and the end face of the resin filler is flush with the base layer surface. Therefore, the surface of the resin insulating layer can be made flat even if a new resin insulating layer is laminated on the base layer in the subsequent step.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) Hereinafter, embodiments of the present invention will be described with reference to the drawings. Embodiment 1
FIG. 1 shows a partially enlarged sectional view of the wiring board 1 on the main surface 3 side. The wiring board 1 has a substantially rectangular plate shape having a main surface 3 and a back surface (not shown). At the center thereof, a substantially plate-shaped core substrate (resin insulating layer) 5 made of a composite material obtained by impregnating glass fiber cloth with epoxy resin is provided. A solder resist layer (resin insulating layer) 7 made of epoxy resin or the like is laminated on each of the surfaces.

Of these, a plurality of through holes 9 having a diameter of about 350 μm are formed in the core substrate 5 at predetermined positions, and the inner peripheral surfaces of the through holes 9 are substantially cylindrical and have a thickness of about 22 μ.
m through-hole conductors 11 are respectively formed.
Then, each through-hole conductor 11 is filled with a substantially cylindrical resin filling body 13 made of epoxy resin or the like. On the other hand, the solder resist layer 7 has a plurality of pad openings 15 penetrating the solder resist layer 7 at predetermined positions.

Between the core substrate 5 and the solder resist layer 7, a wiring layer 21 having a predetermined pattern such as wiring and pads is formed.
(Thickness of about 20 μm) is formed. A part of the wiring layer 21 is connected to the through hole conductor 11 formed on the core substrate 3. Also, the pad 21p of the wiring layer 21
Since the electronic components such as IC chips are mounted on the wiring board 1, the exposed portions are exposed in the pad openings 15 of the solder resist layer 7. In addition, on the surface of the pad 21p,
A Ni plating layer is formed to prevent oxidation, and an Au plating layer is formed on the surface of the Ni plating layer (not shown).

Such a wiring board 1 is manufactured as follows. That is, first, the thickness of the core substrate 5 is about 12
A substantially plate-shaped double-sided copper-clad core substrate 5 with a Cu foil 31 of μm is prepared, and in a through-hole forming step, as shown in FIG.
As shown in, a plurality of through holes 9 are drilled at predetermined positions with a drill. In the present embodiment, the double-sided copper clad core substrate is the base layer 6, and the Cu foil 31 forming the base layer surface 35 is used.
Is a surface conductor layer. Next, in a plating step, the base layer 6 is sequentially subjected to electroless Cu plating and electrolytic Cu plating, and as shown in FIG.
A Cu plating layer 33 of 2 μm is added to form a conductor layer 37 including the copper foil 31 and the Cu plating layer 33. At the same time, a substantially cylindrical through-hole conductor 11 having a thickness of about 22 μm, which is sufficient for conduction, is formed on the inner peripheral surface of the through-hole 9.

Next, in the resin filling body forming step, as shown in FIG.
As shown in FIG. 5, a resin filling body 13 made of epoxy resin or the like is filled in the through hole conductor 11. Specifically, a resin paste is printed and filled in the through-hole conductor 11 using a mask (not shown) having a predetermined pattern having through holes corresponding to the positions and openings of the through-hole conductor 11, and then the resin paste is filled with the resin paste. The resin filling body 13 is formed by thermosetting. At that time, since it is difficult to form the end surface of the resin filling body 13 so as to be flush with the base layer surface 35, a part of the resin filling body 13 (bulging portion 13b) bulges from the base layer surface 35. As described above, the resin filling body 13 is formed in a large size.

Next, in the first removing step, the base layer surface 35 of the base layer 6 on which the resin filler 13 is formed is buffed,
As shown in FIG. 5, the base layer surface 35 of the resin filler 13
The bulging part 13b bulging out from is removed. As a result, the end surface 13m of the resin filling body 13 becomes flush with the base layer surface 35.

Next, in the conductor layer thinning step, as shown in FIG. 6, the conductor layer 37 composed of the Cu foil 31 and the Cu plating layer 33 is thinned by etching. Specifically, the conductor layer 37 having a thickness of about 34 μm is thinned to a thickness of about 25 μm. This thickness is selected in consideration of surely and accurately forming the wiring layer 21 in the subsequent patterning process. In this embodiment, the conductor layer thinning step is performed after the removing step and before the patterning step described later. Therefore, it is possible to reduce only the thickness of the conductor layer 37 on the base layer surface 35 without reducing the thickness of the through-hole conductor 11. That is, the thicknesses of both can be independently determined.

In this step, the conductor layer 37 is etched to be thin overall, but the resin filling body 13 is not etched. As a result, the end portion 1 of the resin filling body 13 is etched.
3t projects from the base layer surface 35. Therefore, the subsequent steps are performed in this state, and the solder resist layer 7 is formed on the base layer 6.
When these are laminated, the surface of the solder resist layer 7 may be uneven, and the flatness of the surface may be impaired. Then, next, in the second removing step, the base layer surface 35 is buffed again to remove the end portion 13t of the resin filler 13 protruding from the base layer surface 35 by the conductor layer thinning step, as shown in FIG. . As a result, the end surface 13m of the resin filling body 13 becomes flush with the base layer surface 35.

Next, in the patterning step, the thinned conductor layer 37 is patterned, and as shown in FIG.
The wiring layer 21 is formed. Specifically, an etching resist layer is formed on the conductor layer 37, and this is exposed and developed to form a predetermined pattern corresponding to the pattern of the wiring layer 21.
Then, the conductor layer 37 exposed from this resist layer is removed by etching. After etching, if the etching resist layer is peeled off, the wiring layer 21 having a predetermined pattern is formed.

At this time, since the conductor layer 37 is sufficiently thinned (thickness is about 25 μm) in the conductor layer thinning step described above,
The wiring layer 21 can be formed reliably and accurately.
That is, the conductor layer 37 to be removed due to insufficient etching is not completely removed and does not remain on the base layer surface 35. Therefore, a short circuit is unlikely to occur in the wiring layer 21. Further, the etching progresses not only in the thickness direction but also in the horizontal direction perpendicular to the thickness direction, and the conductor layer 37 covered with the etching resist layer is also removed by etching, but the conductor layer 37 to be etched is sufficient. Being thin, you can minimize this gouging. Therefore, it is possible to prevent the wiring from being thinned, and the wiring layer 21 is less likely to be opened. Therefore, for example, a fine wiring layer 21 having a line width of about 20 μm
Can be formed. In particular, in the first embodiment, since the conductor layer 37 formed on the base layer 6 is composed of the Cu foil 31 and the Cu plating layer 33 and has a large thickness, various problems are likely to occur in the patterning process. However, since the thick conductor layer 37 is sufficiently thinned in the conductor layer thinning step as described above, the wiring layer 21 can be formed reliably and accurately.

Next, in the solder resist layer forming step, the solder resist layer 7 having the pad openings 15 is formed on the base layer 6. Specifically, a semi-cured solder resist layer is formed on the base layer 6, and exposed and developed using a mask having a predetermined pattern corresponding to the pad openings 15.
Then, it is further heat-treated and cured to form the solder resist layer 7 having a predetermined pattern. At that time, the above-mentioned second
In the removing step, since the protrusion 13t of the resin filling body 13 is removed and the base layer surface 35 is made flat, the surface (main surface 3) of the solder resist layer 7 laminated thereon can also be made flat. After that, in the Ni-Au plating step, a Ni plating layer is formed on the pad 21p exposed from the solder resist layer 7 to prevent oxidation, and an Au plating layer is further formed thereon. In this way, FIG.
The wiring board 1 shown in is completed.

(Second Embodiment) Next, a second embodiment will be described. The description of the same parts as those in the first embodiment will be omitted or simplified. FIG. 9 shows a partially enlarged cross-sectional view of the main surface 103 side of the wiring board 101 according to the second exemplary embodiment. The wiring board 101 has a substantially rectangular plate shape having a main surface 103 and a back surface (not shown). At the center thereof, a substantially plate-shaped core substrate 105 is provided. The first resin insulation layer 1 made of epoxy resin or the like is provided on both sides of the first resin insulation layer 1.
07 are laminated respectively. Further, a second resin insulation layer 109 made of epoxy resin or the like is laminated on the first resin insulation layer 107. In addition, the second resin insulation layer 10
A solder resist layer 111 is laminated on the surface 9.

Of these, a plurality of through holes 113 penetrating the core substrate 105 and the first resin insulating layer 107 are formed at predetermined positions, and the inner wall surface of the through holes 113 has a substantially cylindrical shape with a thickness of about 22 μm. The hole conductors 115 are formed respectively. Each through-hole conductor 115 is filled with a resin filling body 117 having a substantially columnar shape. A plurality of first via holes 119 penetrating the first resin insulating layer 107 are formed at predetermined positions, and a substantially bowl-shaped first via conductor 121 is formed in each first via hole 119. ing. On the other hand, a plurality of second via holes 123 penetrating the second resin insulating layer 109 are formed at predetermined positions, and a substantially bowl-shaped second via conductor 125 is formed in each second via hole 123. ing. Further, the solder resist layer 111 has
A plurality of pad openings 127 passing through this are formed at predetermined positions.

A first wiring layer 131 having a thickness of about 12 μm is formed between the core substrate 105 and the first resin insulating layer 107. The first wiring layer 131 includes the through-hole conductor 1
15 and the first via conductor 121. Also, the first
A second wiring layer 133 having a thickness of about 25 μm is also formed between the resin insulating layer 107 and the second resin insulating layer 109. The second wiring layer 133 is connected to the through-hole conductor 115, the first via conductor 121, and the second via conductor 125. Further, a part of the second wiring layer 133 is a lid plating layer 133f formed on the through hole conductor 115 and the resin filling body 117. And this lid plating layer 1
The second via conductor 125 is directly connected to 33f. In addition, a third wiring layer 135 having a thickness of about 15 μm is provided between the second resin insulation layer 109 and the solder resist layer 111.
Are formed. The third wiring layer 135 is connected to the second via conductor 125. Further, a part of the pad 135p of the second wiring layer 135 is exposed in the pad opening 127 of the solder resist layer 111.

Such a wiring board 101 is manufactured as follows. First, a double-sided copper-clad core substrate 105 is prepared. Then, in the first patterning step, the copper foil is patterned to form the first wiring layer 1 as shown in FIG.
31 is formed. Specifically, the first wiring layer 13 is formed on the copper foil.
An etching resist layer (not shown) having a predetermined pattern corresponding to the pattern 1 is formed. Then, the copper foil exposed from this resist layer is removed by etching. After etching, if the etching resist layer is peeled off, the first wiring layer 131 having a predetermined pattern is formed.

Next, in the first insulating layer forming step, the first resin insulating layer 1 is formed on the core substrate 105 and the first wiring layer 131.
07 is formed (see FIG. 11). In the second embodiment, this substrate becomes the base layer 140. Next, a plurality of first via holes 119 are drilled at predetermined positions by a laser, and the through holes 1 are drilled in the through hole forming step.
Plural holes 13 are drilled at predetermined positions. After that, in the first plating step, electroless Cu plating and electrolytic Cu plating are sequentially applied to the base layer 140, and as shown in FIG.
0 (first resin insulation layer 107) has a thickness of approximately 22 μm over substantially the entire surface.
Of the first Cu plated layer (first conductor layer) 141 is formed, and the first via conductor 121 having a substantially bowl shape is formed in the first via hole 119.
On the inner peripheral surface of the through hole 113, a substantially cylindrical through hole conductor 115 having a thickness of about 22 μm is formed.

Next, in the resin filling body forming step, as shown in FIG.
As shown in FIG. 2, a resin filling body 117 is formed in the through hole conductor 115. The manufacturing method is the same as that of the first embodiment. The bulging portion 117b of the resin filling body 117 bulges from the base layer surface 143. Next, in the first removing step, the base layer surface 14 of the base layer 140 on which the resin filler 117 is formed
3 is buffed, and as shown in FIG.
The bulging portion 117b bulging from the base layer surface 143 of No. 7 is removed. As a result, the end surface 117 of the resin filling body 117 is
m is flush with the base layer surface 143.

Next, in the conductor layer thinning step, as shown in FIG. 14, the first Cu plating layer (first layer) on the surface 143 of the base layer is formed.
The conductor layer 141 is thinned by etching. Specifically, the first Cu plating layer 141 having a thickness of about 22 μm is thinned to a thickness of about 15 μm. This thickness is the second
The selection is made in consideration of the fact that the second Cu plated layer 145 is overlaid and formed in the plating step and that the second wiring layer 133 is formed reliably and accurately in the patterning step.
In this step, the first Cu plated layer 141 is etched to be thin overall, but the resin filler 117 is not etched. As a result, the end 117t of the resin filler 117 projects from the base layer surface 143. For this reason,
In this state, the subsequent steps are performed to form a second layer on the base layer 140.
When the resin insulation layer 109 is formed, the second resin insulation layer 109 is formed.
There is a risk that unevenness will occur on the surface of the and the flatness of the surface will be impaired.

Then, next, in the second removing step, the base layer surface 143 is polished again, and as shown in FIG. 15, the base layer surface 143 of the resin filler 117 is subjected to the conductor layer thinning step.
The end 117t protruding from is removed. As a result, the end surface of the resin filling body 117 becomes flush with the base layer surface 143.

Next, in the second plating step, the base layer 14
No. 0 is sequentially subjected to electroless plating and electrolytic plating, and as shown in FIG. 16, a second Cu plating layer (second
Conductor layer) 145 is formed. At this time, the resin filling body 11
7 for directly connecting the second via conductor 125,
A so-called lid plating layer 145f (thickness: about 12 μm) is formed.

Here, the above-described conductor layer thinning step needs to be performed not only before the patterning step described later, but also before this Cu plating step. If the second plating step is performed before the conductor layer thinning step, the portion other than the resin filling body 117 (the resin filling body 11)
7), the conductor layer 147 of the periphery 7) is the first
Second Cu to be formed later on the Cu plating layer 141
Since the plating layer 145 is added, the conductor layer 147 becomes thick.
On the other hand, the second Cu plating layer 14 is formed on the resin filler 117.
5 (lid plating layer 145f) is formed. Therefore, when the conductor layer forming step is performed thereafter to reduce the thickness of the conductor layer 147, the second portion on the resin filling body 117 is reduced.
The Cu plating layer 145 (lid plating layer 145f) may be almost removed. On the contrary, the resin filler 117
If an attempt is made to secure a certain thickness of the upper second Cu plating layer 145 (lid plating layer 145f), the thick portion of the conductor layer 147 can hardly be thinned, and as a result, during patterning, between the wirings, There is a problem that Cu remains and a problem that wiring is thinned.

However, in this embodiment, since the conductor layer thinning step is performed before the second plating step, the second Cu plating layer 145 (the lid plating layer 14) on the resin filling body 117 is performed.
The thickness of the conductor layer 147 on the base layer surface 143 can be made sufficiently thin while ensuring a sufficient thickness without reducing the thickness of 5f). Moreover, this thickness can be determined independently of the thickness of the through-hole conductor 115.

Next, in the second patterning step, the conductor layer 147 including the first Cu plated layer 141 and the second Cu plated layer 145 is patterned to form a second wiring layer 133 as shown in FIG. As a method of making, an etching resist layer (not shown) having a predetermined pattern corresponding to the pattern of the second wiring layer 133 is formed on the conductor layer 147 as in the first patterning step. Then, the conductor layer 147 exposed from this resist layer is removed by etching. After etching, the etching resist layer is peeled off.

At this time, since the conductor layer 147 is sufficiently thinned (thickness is about 27 μm) by the conductor layer thinning step,
The second wiring layer 133 can be formed reliably and accurately. That is, the conductor layer 1 to be removed due to insufficient etching
47 is not completely removed and does not remain on the base layer surface 143. Therefore, a short circuit is unlikely to occur in the second wiring layer 133. Further, the conductor layer 147 covered with the etching resist layer is also removed by the etching, but since the conductor layer 147 to be etched is sufficiently thin, this removal can be minimized. Therefore, it is possible to prevent the wiring from being thinned, and it is difficult for the second wiring layer 133 to be opened. Therefore, fine wiring can be formed.

Next, in the second insulating layer forming step, as shown in FIG.
8, the second resin insulation layer 109 is formed on the base layer 140.
To form. At that time, in the above-described second removing step, the protrusion 117t of the resin filling body 117 is removed, and the base layer surface 1
Since 43 is made flat, the surface of the second resin insulation layer 109 laminated thereon can also be made flat. Next, a plurality of second via holes 123 are drilled at predetermined positions with a laser. After that, electroless Cu plating and electrolytic Cu plating are sequentially performed, and a thickness of about 15 μm is formed on substantially the entire surface of the second resin insulation layer 109.
A Cu plated layer 151 of m is formed, and a substantially bowl-shaped second via conductor 125 is formed in the second via hole 123. As a result, some of the second via conductors 125 are covered by the lid plating layer 14
It is directly connected to the through-hole conductor 115 via 5f.

Next, in a third patterning step, the Cu plating layer 151 on the second resin insulating layer is patterned to form a third wiring layer 135, as shown in FIG. The patterning method is the same as that for the first wiring layer 131 and the second wiring layer 133. Next, in the solder resist layer forming step, the second resin insulation layer 109 and the third resin insulation layer 109
A solder resist layer 111 having a pad opening 127 is formed on the wiring layer 135. The manufacturing method is the same as that of the first embodiment, and thereafter, in the Ni-Au plating step, the pad 13 exposed from the solder resist layer 111.
A Ni plating layer is formed on 5p, and an Au plating layer is further formed thereon. In this way, the wiring board 101 shown in FIG. 9 is completed.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the first and second embodiments, and is appropriately modified and applied without departing from the scope of the invention. It goes without saying that you can do it. For example, in each of the plating steps of Embodiments 1 and 2 described above, the electroless plating is performed and then the electroplating is performed to form the plating layer. However, for example, the electroless plating may be used to form the plating layer. May be. In the conductor layer thinning step of each of the first and second embodiments, the conductor layers 37 and 141 are thinned by etching, but the conductor layer 3 is mechanically polished or the like.
It is also possible to make 7,141 thinner. Further, in the second embodiment, the electroless plating and the electrolytic plating are sequentially performed in the second plating step.
By using a resin (metal powder-containing resin) that can be directly electroplated, it is possible to perform only electroplating.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a wiring board according to a first embodiment.

FIG. 2 is an explanatory diagram showing a state in which through holes are formed in a base layer in the method for manufacturing a wiring board according to the first embodiment.

FIG. 3 is an explanatory diagram showing a state where a Cu plating layer and a through-hole conductor are formed on a base layer in the method for manufacturing a wiring board according to the first embodiment.

FIG. 4 is an explanatory view showing a state where a resin filling body is formed in the through-hole conductor in the method for manufacturing the wiring board according to the first embodiment.

FIG. 5 is an explanatory diagram showing a state in which a bulging portion of a resin filling body is polished and removed in the method for manufacturing a wiring board according to the first embodiment.

FIG. 6 is an explanatory diagram showing a state in which the thickness of the conductor layer on the surface of the base layer is reduced in the method for manufacturing a wiring board according to the first embodiment.

FIG. 7 is an explanatory diagram showing a state where the end portion of the resin filling body is polished and removed in the method for manufacturing the wiring board according to the first embodiment.

FIG. 8 is an explanatory diagram showing a state in which a conductor layer is patterned to form a wiring layer in the method of manufacturing the wiring board according to the first embodiment.

FIG. 9 is a partially enlarged cross-sectional view of a wiring board according to a second embodiment.

FIG. 10 is an explanatory diagram showing a state in which a first wiring layer is formed on a core substrate in the method of manufacturing the wiring substrate according to the second embodiment.

FIG. 11 is an explanatory view showing a state in which a first Cu plating layer, a first via conductor and a through hole conductor are formed in a base layer in the method for manufacturing a wiring board according to the second embodiment.

FIG. 12 is an explanatory diagram showing a state where a resin filling body is formed in a through-hole conductor in the method for manufacturing a wiring board according to the second embodiment.

FIG. 13 is an explanatory diagram showing a state in which a bulging portion of a resin filling body is polished and removed in the method for manufacturing a wiring board according to the second embodiment.

FIG. 14 is an explanatory diagram showing a state in which the thickness of the conductor layer on the surface of the base layer is reduced in the method for manufacturing the wiring board according to the second embodiment.

FIG. 15 is an explanatory diagram showing a state where the end portion of the resin filling body is polished and removed in the method for manufacturing the wiring board according to the second embodiment.

FIG. 16 is an explanatory diagram showing a state in which a second Cu plated layer is formed in the method for manufacturing the wiring board according to the second embodiment.

FIG. 17 is an explanatory view showing a state in which the second wiring layer is formed by patterning the conductor layer in the method for manufacturing the wiring board according to the first embodiment.

FIG. 18 is an explanatory diagram showing a state in which a Cu plating layer and a second via conductor are formed in the second resin insulating layer in the method for manufacturing the wiring board according to the second embodiment.

FIG. 19 is an explanatory diagram showing a state in which a third wiring layer is formed on the second resin insulating layer in the method of manufacturing the wiring board according to the second embodiment.

[Explanation of symbols]

1, 101 Wiring board 5 Core board 6, 140 Base layer 9, 113 Through hole 11, 115 Through hole conductor 13, 117 Resin filling body 13b, 117b (Resin filling body) Swelling portion 13t, 117t (Resin filling body) Edge 21 Wiring layer 31 Copper foil (surface conductor layer) 33 Cu plating layer (plating layer) 35,143 Base layer surface 37 (consisting of surface conductor layer and plating layer) Conductor layer 133 Second wiring layer 141 First Cu plating layer (First conductor layer) 145 Second Cu plating layer (second conductor layer) 145f Lid plating layer 147 (consisting of first conductor layer and second conductor layer) Conductor layer

Continued front page    F term (reference) 5E314 AA24 BB05 BB13 CC01 DD05                       DD07 DD08 FF05 FF17 GG14                 5E317 AA24 BB01 BB11 CC31 CC44                       CC51 CD01 CD23 CD25 CD27                       CD32 GG01 GG14 GG16                 5E339 AB02 AC01 AD03 AE01 BD02                       BD03 BD08 BD11 BE11 CE06                       CE10 EE10 GG02                 5E346 AA05 AA06 AA42 AA43 BB01                       CC02 CC08 CC32 DD01 DD32                       EE33 FF04 GG15 GG17 GG22                       GG28 HH07

Claims (4)

[Claims] 1. A through hole forming step of forming a through hole in a base layer, and a plating step of forming a conductor layer on the surface of the base layer by plating and forming a through hole conductor on the inner wall surface of the through hole. A resin filling body forming step of forming a resin filling body in the through-hole conductor; a removing step of removing a portion of the resin filling body that bulges from the base layer surface; and a removing step after the removing step. A method for manufacturing a wiring board, comprising: a conductor layer thinning step of reducing the thickness of the conductor layer; and a patterning step of patterning the thinned conductor layer to form a wiring layer. 2. The method for manufacturing a wiring board according to claim 1, wherein the conductor layer thinning step is a step of thinning the conductor layer on the surface of the base layer by etching. After the step and before the patterning step, the method for manufacturing a wiring board further includes a second removing step of removing a portion of the resin filling body protruding from the surface of the base layer. 3. A through-hole forming step of forming a through-hole in a base layer, plating is performed to form a first conductor layer on a surface of the base layer, and a through-hole conductor is formed on an inner wall surface of the through hole. 1 plating step, a resin filling body forming step of forming a resin filling body in the through-hole conductor, a removing step of removing a portion of the resin filling body that bulges from the surface of the base layer, and after the removing step, Conductor layer thinning step for reducing the thickness of the first conductor layer on the surface of the base layer, and plating again after the conductor layer thinning step to form a second conductor layer on the surface of the base layer including on the resin filling body. Second
A method of manufacturing a wiring board, comprising: a plating step; and a patterning step of patterning a conductor layer including the first conductor layer and the second conductor layer to form a wiring layer. 4. The method of manufacturing a wiring board according to claim 3, wherein the conductor layer thinning step is a step of thinning the thickness of the first conductor layer on the surface of the base layer by etching. After the thinning step and before the second plating step, a method of manufacturing a wiring board further comprising a second removing step of removing a portion of the resin filler protruding from the surface of the base layer.