JP4503698B2 - Wiring board manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a wiring board, and more particularly to a method for manufacturing a multilayer wiring board in which a plurality of conductive patterns are electrically connected and stacked via vias that penetrate an insulating layer.

As a method for manufacturing a multilayer wiring board, for example, the following patent document proposes a method for manufacturing a wiring board shown in FIG.
In the method of manufacturing a wiring board shown in FIG. 8, first, as shown in FIG. 8A, a peelable metal foil 102 is laminated on one side of a resin plate 100 made of a semi-cured resin as a strong carrier. As shown in FIG. 9, the peelable metal foil 102 has a metal plate 102b thicker than the metal foil 102a bonded to one surface side of the metal foil 102a via a peel layer 102c. When the peelable metal foil 102 is laminated on one surface side of the resin plate 100, the two can be bonded together by thermocompression bonding with the metal foil 102a and the resin plate 100 joined.
As shown in FIG. 8B, the metal plate 102b side of the peelable metal foil 102 laminated on one surface side of the resin plate 100 is partially covered with a dry film 104 and then etched on the exposed surface of the metal plate 102b. Are formed to form the bump recesses 106, 106,... And the dry film 104 is removed [FIG. 8 (c)].
In the bump recesses 106, 106,..., As shown in FIG. 8D, bumps 108 are formed by plating metal and a conductor pattern 110 connected to the bumps 108 is formed. When the bumps 108 are formed, as will be described later, a metal film 112 such as gold that is not etched is formed in an etching solution that etches the metal plate 102b.

Further, as shown in FIG. 8E, conductor patterns 118, 118,... Are formed on the bumps 108 and the conductor patterns 110 by an additive method or a semi-additive method, and insulating layers 114, 114,. Vias 116, 116,... Penetrating are formed.
In this way, by laminating a predetermined number of conductor patterns on the metal plate 102b of the peelable metal foil 102, the strength of the formed wiring board 120 is improved. As shown in FIG. The metal plate 102b and the metal foil 102a of the conductive metal foil 102 are peeled off.
Thereafter, the wiring board 120 can be obtained by removing the metal plate 102b by etching.

JP 2007-165513 A

According to the method for manufacturing a wiring board shown in FIG. 8, since the strength can be maintained by the resin plate 100 as a strong carrier, a multilayer wiring board can be easily transported while carrying a laminate in the manufacturing process of the wiring board. Can be manufactured.
However, in the method of manufacturing the wiring board shown in FIG. 8, the metal plate 102b adhering to the wiring board 120 peeled from the resin plate 100 is removed by etching. In order to shorten the etching time, it is necessary to use a thin metal plate 102. However, in order to form the concave portions 106, 106,... For bumps in the metal plate 102, the metal plate 102 having a predetermined thickness is required. For this reason, it is difficult to shorten the time for etching the metal plate 102.
Therefore, the present invention eliminates the problem of the conventional method of manufacturing a wiring board in which the metal plate is etched away after forming the wiring board formed on the metal plate having a predetermined thickness, and the metal plate is etched away. Provided is a method for manufacturing a wiring board which is not required.

In order to solve the above problems, the present inventors advantageously form a conductor pattern using a metal foil with a carrier in which a metal foil is laminated on one side of a carrier plate as a support via a release layer. The present invention has been reached as a result of studying it.
That is, the present invention includes: (a) preparing a plurality of metal foils with a carrier provided with metal foils on one side of a carrier plate as a support through a release layer; and (b) first and second steps. (C) bonding the metal foil with carrier so that the metal foils face each other through the first insulating layer, and then peeling the carrier plate of the first metal foil with carrier to expose the metal foil; ) After the step (b), using the carrier plate of the metal foil with the second carrier as a support, the metal foil of the metal foil with the second carrier is exposed from the metal foil of the metal foil with the first carrier. Forming a first via hole in the first insulating layer; and (d) after the step (c), filling the first via hole with metal to form a first via in the first insulating layer. And forming a first conductor pattern on the first insulating layer; e) After the step (d), the metal foil with the third carrier faces the first conductor pattern side through the second insulating layer, and the metal foil of the first conductor pattern and the metal foil with the third carrier faces each other. And the step of peeling the carrier plate of the third metal foil with carrier to expose the metal foil, and (f) the carrier plate of the metal foil with second carrier after the step (e). A step of forming a second via hole in the second insulating layer so as to expose the first conductor pattern from the metal foil of the third metal foil with a carrier as a support; and (g) after the step (f) The second via hole is filled with metal to form a second via in the second insulating layer and electrically connected to the metal foil of the third carrier-attached metal foil on the second insulating layer. circuit base which comprises forming a second conductive pattern, was It is a method of manufacture.
Further, after the step (f) and before the step (g), the carrier plate of the metal foil with the second carrier is peeled to expose the metal foil, and together with the step (g), on the first insulating layer And forming a third conductor pattern electrically connected to the metal foil of the second carrier-attached metal foil.

(H) After the step (g), a metal foil with a fourth carrier is provided on the second conductor pattern side via a third insulating layer, and the metal foil of the second conductor pattern and the metal foil with the fourth carrier. Are disposed so as to face each other, and then the step of peeling the carrier plate of the metal foil with the fourth carrier to expose the metal foil, (i) after the step (h), Forming a third via hole in the third insulating layer so as to expose the second conductor pattern from the metal foil of the fourth metal foil with carrier using the carrier plate as a support; and (j) the above (i ) After the step, the metal is filled into the third via hole to form a third via in the third insulating layer, and the metal foil of the metal foil with the fourth carrier is electrically formed on the third insulating layer. Forming a third conductor pattern connected to the substrate. It is also a method for manufacturing a wiring substrate.
Further, after the step (i) and before the step (j), the metal foil is exposed by peeling the carrier plate of the metal foil with the second carrier, and together with the step (j), on the first insulating layer And forming a fourth conductor pattern electrically connected to the metal foil of the second carrier-attached metal foil.

In the step (a), a carrier plate is a copper plate, a metal foil is a copper foil, and a plurality of metal foils with a carrier in which a copper foil is provided on one side of the carrier plate via a release layer is prepared. This is also a method for manufacturing a wiring board.
Further, in the step of forming the via hole, a via hole is formed in the target insulating layer by a laser, and in the step of forming the via, the via is formed by filling the target via hole with a plating metal. It is also a characteristic method for manufacturing a wiring board.

According to the method for manufacturing a wiring board according to the present invention, the step of removing the metal plate by etching, which was necessary in the conventional method for manufacturing the wiring board shown in FIG. 8, can be eliminated, and the manufacturing process of the wiring board can be shortened. .
Furthermore, in the present invention, since the carrier plate of the metal foil with carrier is used as a strong carrier, the strength of the laminate during the manufacturing process can be maintained, and troubles caused by deformation of the laminate due to rollers in the manufacturing process can be maintained. Can be prevented.

It is a part of process drawing explaining the reference example of the manufacturing method of the wiring board which concerns on this invention. It is process drawing explaining the remaining processes of the manufacturing method of the wiring board shown in FIG. It is a fragmentary sectional view explaining an example of the metal foil with a carrier used with the manufacturing method of the wiring board shown in FIG.1 and FIG.2. It is a part of process drawing explaining an example of the manufacturing method of the wiring board which concerns on this invention. It is process drawing explaining the remaining processes of the manufacturing method of the wiring board shown in FIG. It is a part of process drawing explaining the other example of the manufacturing method of the wiring board which concerns on this invention. It is process drawing explaining the remaining processes of the manufacturing method of the wiring board shown in FIG. It is process drawing explaining the manufacturing method of the conventional wiring board. It is a fragmentary sectional view explaining the peelable metal foil used with the manufacturing method of the conventional wiring board.

A reference example of a method for manufacturing a wiring board according to the present invention is shown in FIGS. First, as shown to Fig.1 (a), the copper foil 14 as a metal layer thicker than the metal foil 10b is laminated | stacked through the insulating layer 12 which consists of resin on the metal foil 10b side of the metal foil 10 with a carrier. As this copper foil 14, a copper foil having a thickness of 18 μm was used.
The lamination of the metal foil with carrier 10 and the copper foil 14 can be performed by heating and press-bonding the insulating layer 12 from a semi-cured thermosetting resin using a sheet.
Moreover, as shown in FIG. 3, the metal foil 10 with a carrier is provided with a metal foil 10b on one side of a carrier plate 10a as a strong carrier via a peeling layer 10c. A copper plate having a thickness of 15 to 70 μm can be used as the carrier plate 10a, and a copper foil having a thickness of 0.5 to 12 μm can be used as the metal foil 10b.

The surface of the copper foil 14 shown in FIG. 1A is partially covered with a dry film 16 as shown in FIG. At this time, the entire surface of the carrier plate 10 a of the metal foil with carrier 10 is also covered with the dry film 16.
By etching the part of the copper foil 14 where the surface is partially exposed and peeling off the dry film 16, the first conductor patterns 18, 18,... Can be formed as shown in FIG. Since the first conductor patterns 18, 18,... Are formed at the center of the wiring board as will be described later, they can be suitably used for feeding or grounding.
Further, as shown in FIG. 1 (d), the first conductor patterns 18, 18,... Are arranged so that the metal foil 10b is opposed to the first conductor patterns 18, 18. The metal foil with carrier 10 is disposed on the side. Also in this case, the insulating layer 12 can be formed by heating and pressure bonding using a sheet from a semi-cured thermosetting resin.

As shown in FIG. 1 (e), the carrier plates 10a and 10a of the metal foils 10 and 10 with a carrier disposed so as to sandwich the first conductor patterns 18 and 18 obtained in this way are peeled off. The board | substrate 20 which comprises the metal foils 10b and 10b through the insulating layers 12 and 12 can be obtained on both surface sides of the first conductor patterns 18, 18,.
Since the obtained substrate 20 has the insulating layers 12 and 12 formed on both sides of the first conductor patterns 18, 18..., Even if the carrier plates 10 a and 10 a that have been used as strong carriers are peeled off, The substrate 20 can be sufficiently transported.
As shown in FIG. 1 (f), via holes 22, 22,... In which the first conductor pattern 18 is exposed on the bottom surface are formed at predetermined positions of the metal foils 10b, 10b of the substrate 20, as shown in FIG. Since the via hole 22 is formed by a laser, the via hole 22 is formed in a tapered shape in which the inner diameter gradually decreases from the opening toward the bottom surface. Thus, the residue generated by forming the via holes 22, 22... By the laser was removed by applying a desmear process to the substrate 20.
As shown in FIG. 2 (a), thin metal films 23, 23 are formed on the entire surface of the substrate 20 including the inner wall surfaces of the via holes 22, 22,.
Further, as shown in FIG. 2 (b), after patterning with the dry films 16 and 16, via plating using the metal foil 10b and the thin metal film 23 as a power feeding layer and via fill electroplating as a power feeding layer is performed. The vias 24 and 24 are formed by filling the holes 22, 22... With plating metal, and the conductor patterns 28 electrically connected by the first conductor patterns 18, 18. 28... Can be formed on both sides of the substrate 20.

Next, as shown in FIG. 2C, the first conductor is formed as shown in FIG. 2C by etching the metal foil 10b and the thin metal film 23 exposed by peeling off the dry films 16 and 16. The conductor patterns 28, 28,... Electrically connected by the patterns 18, 18,... And the vias 24, 24,.
Furthermore, as shown in FIG. 2D, the wiring substrate 30 can be obtained by covering the conductive patterns 28, 28,... With the solder resist 32 except for the portions where the pads 34 are formed.
As described above, in the method of manufacturing the wiring board shown in FIGS. 1 and 2, the board 20 having the metal foils 10 b and 10 b on both sides of the first conductor patterns 18, 18. In the process up to formation, since the carrier plate 10a of the metal foil with carrier 10 is used as a strong carrier, the conveyance in the manufacturing process of the laminated body and the like can be performed without any problems.
Further, the process of removing the metal plate 102b by etching as in the method of manufacturing the wiring board shown in FIG. 8 can be eliminated, and the manufacturing process of the wiring board 30 can be shortened.

In the method of manufacturing the wiring board shown in FIGS. 1 and 2, when forming the via holes 22 and 22 from both sides of the first conductor pattern 18 with a laser, as shown in FIG. After the via hole 22 is formed with a laser from one surface side of the metal 18, the via hole 22 is formed with a laser from the other surface side of the first conductor pattern 18 with the first conductor pattern 18 exposed at the bottom surface of the via hole 22. When doing so, the first conductor pattern 18 exposed on the bottom surface of the already formed via hole 22 may be destroyed.
In this regard, according to the method of manufacturing a wiring board shown in FIGS. 4 and 5 as an example of the method of manufacturing the wiring board according to the present invention, the via hole 22 is formed by laser from one surface side of the first conductor pattern 18. In the state where the first conductor pattern 18 is exposed on the bottom surface of the via hole 22, it is not necessary to form the via hole 22 from the other surface side of the first conductor pattern 18, and the first conductor pattern 18 may be destroyed. Can be eliminated.

First, as shown in FIG. 4A, two metal foils 10 and 10 with a carrier are joined so that the metal foils 10b and 10b face each other through an insulating layer 12 made of a resin. Form. This bonding can be performed by sandwiching a sheet from a semi-cured thermosetting resin as the insulating layer 12 between the metal foils 10 and 10 with a carrier, and heating and pressure bonding.
Further, as shown in FIG. 4B, after one carrier plate 10a of the metal foils 10 and 10 with a carrier is peeled off to obtain a laminated body in which the metal foil 10b is exposed, a predetermined portion of the metal foil 10b is formed. Via holes 22, 22... Exposing the other metal foil 10b of the carrier-attached metal foil 10 are formed on the bottom surface by the laser [FIG. 4 (c)]. Since the via hole 22 is formed by a laser, the via hole 22 is formed in a tapered shape in which the inner diameter gradually decreases from the opening toward the bottom surface. The residue generated by forming the via holes 22, 22... By laser was removed by applying a desmear process to the substrate 20.
As shown in FIG. 4 (d), thin metal films 23, 23 are formed on the entire surface on one side of the insulating layer 12 including the inner wall surfaces of the via holes 22, 22,. .
Further, as shown in FIG. 4 (e), after patterning with the dry films 16 and 16, via fill electroplating using the metal foil 10b and the thin metal film 23 as a power feeding layer, the via holes 22, 22,. The via 24 can be formed by filling the plating metal, and the first conductor patterns 18, 18... Can be formed.
After the dry film 16 is peeled off, the exposed metal foil 10b and the thin metal film 23 are etched to form first conductor patterns 18, 18,... And vias 24, as shown in FIG. 24 can be formed.
The metal with carrier through the insulating layer 12 made of resin on the side of the first conductor patterns 18, 18... So that the first conductor patterns 18, 18. The foil 10 is disposed [FIG. 4 (g)].

Of the metal foils 10 and 10 with a carrier disposed so as to sandwich the first conductor patterns 18, 18... And the vias 24 and 24 shown in FIG. The carrier plate 10a of the metal foil 10 with one carrier is peeled off, and the metal foil 10b on the first conductor patterns 18, 18,... Side is exposed as shown in FIG.
Via holes 22, 22... In which the first conductor pattern 18 or the vias 24 are exposed to the bottom surface are formed by laser at a predetermined portion of the exposed metal foil 10 b [FIG. 5B]. At this time, even if the laser is irradiated to one surface side of the first conductor pattern 18 exposed at the bottom surface of the via hole 22, the insulating layer 12 or the via 24 is formed on the other surface side of the first conductor pattern 18. Therefore, it is possible to prevent the first conductor pattern 18 from being destroyed by the impact irradiated with the laser.
Next, the carrier plate 10a of the metal foil with carrier 10 on which the vias 24 and 24 are formed is peeled off, and the thin metal film 23, by electroless plating or vapor deposition on both surfaces of the substrate 20 where the metal foils 10b and 10b are exposed. 23 is formed. The thin metal film 23 is also formed on the inner wall surfaces of the via holes 22, 22.
Further, after patterning with the dry film 16, the via 24 is formed by filling the via holes 22, 22... With plating metal by via fill electroplating using the metal foil 10 b and the thin metal film 23 as a power feeding layer. The conductor patterns 28, 28,... Can be formed on both sides of the substrate 20 [FIG.
After that, the metal foil 10b and the thin metal film 23 exposed by peeling off the dry films 16 and 16 are etched to be electrically connected by the first conductor patterns 18 and 18 and the vias 24 and 24. The conductor patterns 28, 28... Can be formed on both sides of the substrate 20.
Further, by covering the conductive patterns 28, 28,... With the solder resist 32 except for the portions where the pads 34 are formed, a wiring board can be obtained.

In the method for manufacturing a wiring board shown in FIGS. 1 to 5, a wiring board in which three layers of conductive patterns are laminated is manufactured. In order to prevent the occurrence, conductor patterns are simultaneously formed on both sides of the substrate 20 by a known additive method or semi-additive method.
As described above, in the method of manufacturing a wiring board shown in FIGS. 1 to 5, a wiring board in which odd-numbered conductor patterns are laminated can be obtained.
Further, the carrier plates 10a and 10a of the metal foils 10 and 10 with a carrier sandwiching the first conductor patterns 18, 18... And the vias 24, 24. A wiring board on which layered conductor patterns are laminated can be obtained.
In contrast to the method for manufacturing the wiring substrate shown in FIGS. 1 to 5, according to the manufacturing method shown in FIGS. 6 and 7, a wiring substrate in which an even number of conductive patterns are laminated can be obtained.

In contrast to the method for manufacturing the wiring substrate shown in FIGS. 1 to 5, according to the manufacturing method shown in FIGS. 6 and 7, a wiring substrate in which an even number of conductive patterns are laminated can be obtained.
First, a thin metal film 23 is formed on the entire surface of the resin layer 12 side where the via holes 22 and 22 shown in FIG. The thin metal film 23 is also formed on the inner wall surfaces of the via holes 22, 22.
Further, after patterning with the dry film 16, the via 24 is formed by filling the via holes 22, 22... With plating metal by via fill electroplating using the metal foil 10 b and the thin metal film 23 as a power feeding layer. The second conductor patterns 36, 36,... Are formed [FIG.
The metal foil 10b and the thin metal film 23 exposed by peeling off the dry films 16 and 16 are etched to electrically connect the first conductor patterns 18 and 18 and the vias 24 and 24 and so on. After forming the two conductor patterns 36, 36,..., The resin layer 12 is formed.
Further, as shown in FIG. 6B, the carrier-attached metal foil 10 is laminated on the resin layer 12 formed on the second conductor patterns 36, 36. The metal foil with carrier 10 is laminated so that the metal foil 10b and the second conductor patterns 36, 36,.
The carrier plate 10a of the carrier-attached metal foil 10 on the second conductor patterns 36, 36... Is peeled off [FIG. 6 (c)].

Via holes 22, 22,... Are formed by laser on the exposed metal foil 10b side as shown in FIG.
Further, after the carrier plate 10a of the remaining metal foil with carrier 10 is peeled off, thin metal films 23, 23 are formed on both surfaces of the substrate 20 where the metal foils 10b, 10b are exposed by electroless plating or vapor deposition. The thin metal film 23 is also formed on the inner wall surfaces of the via holes 22, 22. [FIG. 7B].
Then, after patterning with the dry film 16, the via 24 is formed by filling the via holes 22, 22... With plating metal by via fill electroplating using the metal foil 10 b and the thin metal film 23 as a power feeding layer. The conductor patterns 28, 28,... Electrically connected by the first conductor pattern 18, the second conductor pattern 36 and the via 24 can be formed on both sides of the substrate 20 [FIG. 7 (c)].
As described above, in the method of manufacturing a wiring board shown in FIGS. 6 and 7, a wiring board in which even-numbered conductor patterns are laminated can be obtained.
Further, by peeling both the carrier plates 10a and 10a of the metal foils 10 and 10 with a carrier sandwiching the first conductor pattern 18, the second conductor pattern 36 and the vias 24, 24,... Shown in FIG. A wiring board in which an even number of conductive patterns are laminated can be obtained.

In the above description, the via hole 22 is formed by laser, but the via hole 22 can be formed using the metal foil 10b provided in the resin layer 12 made of a photosensitive resin. In this case, after removing a predetermined portion of the metal foil 10b with a laser, the exposed resin layer 12 made of the photosensitive resin is exposed and developed using the remaining metal foil 10b as a mask, whereby the via hole 22 can be formed.
Or after forming the recessed part which the metal foil 10b exposes to a bottom face in the predetermined place in the resist apply | coated on the metal foil 10b, the exposed metal foil 10b is removed by an etching and the resin layer 12 which consists of photosensitive resin is exposed. Next, the exposed resin layer 12 can also be formed by exposing and developing.
Further, when the via 24 is formed by filling the via hole 22 with the metal, the via filling method by electrolytic plating has been described. However, even if the via 24 is formed by filling the via hole 24 with the conductive paste, the via 24 is formed. Good.
The conductor pattern may be formed after the via 24 is formed.

DESCRIPTION OF SYMBOLS 10 Metal foil 10a with a carrier Carrier board 10b Metal foil 10c Peeling layer 12 Insulating layer 14 Copper foil 16 Dry film 18 1st conductor pattern 20 Substrate 22 Via hole 23 Thin metal film 24 Via 28 Conductor pattern 32 Solder resist 34 Pad 36 2nd Conductor pattern

Claims (6)

(A) preparing a plurality of metal foils with a carrier provided with a metal foil via a release layer on one side of a carrier plate as a support;
(B) After joining the first and second metal foils with a carrier so that the respective metal foils face each other via the first insulating layer, the carrier plate of the metal foil with the first carrier is peeled off to form a metal foil. Exposing the step,
(C) After the step (b), using the carrier plate of the second metal foil with carrier as a support, the metal foil of the second metal foil with carrier is exposed from the metal foil of the first metal foil with carrier. And forming a first via hole in the first insulating layer;
(D) After the step (c), the first via hole is filled with metal to form a first via in the first insulating layer, and a first conductor pattern is formed on the first insulating layer. Process,
(E) After the step (d), the metal foil with the third carrier faces the first conductor pattern side through the second insulating layer, and the metal foil of the first conductor pattern and the metal foil with the third carrier faces each other. After disposing so as to peel off the carrier plate of the metal foil with the third carrier to expose the metal foil,
(F) After the step (e), using the carrier plate of the metal foil with the second carrier as a support, the second insulation so as to expose the first conductor pattern from the metal foil of the metal foil with the third carrier. Forming a second via hole in the layer;
(G) After the step (f), a metal is filled in the second via hole to form a second via in the second insulating layer, and the third carrier-attached metal foil on the second insulating layer Forming a second conductor pattern electrically connected to the metal foil;
The manufacturing method of the wiring board characterized by including. In the manufacturing method of the wiring board of Claim 1,
After the step (f), before the step (g), the carrier plate of the metal foil with the second carrier is peeled to expose the metal foil,
A method of manufacturing a wiring board, comprising forming a third conductor pattern electrically connected to the metal foil of the second metal foil with a carrier on the first insulating layer together with the step (g). In the manufacturing method of the wiring board of Claim 1,
(H) After the step (g), the metal foil with the fourth carrier faces the second conductor pattern side via the third insulating layer, and the metal foil of the second conductor pattern and the metal foil with the fourth carrier faces each other. A step of peeling the carrier plate of the metal foil with the fourth carrier to expose the metal foil,
(I) After the step (h), third insulation is performed so that the second conductive pattern is exposed from the metal foil of the fourth metal foil with carrier using the carrier plate of the second metal foil with carrier as a support. Forming a third via hole in the layer;
(J) After the step (i), the third via hole is filled with metal to form a third via in the third insulating layer, and the fourth carrier-attached metal foil on the third insulating layer Forming a third conductor pattern electrically connected to the metal foil;
The manufacturing method of the wiring board characterized by including. In the manufacturing method of the wiring board of Claim 3,
After the step (i) and before the step (j), the carrier plate of the second metal foil with carrier is peeled to expose the metal foil,
A method of manufacturing a wiring board, comprising forming a fourth conductor pattern electrically connected to the metal foil of the second metal foil with a carrier on the first insulating layer together with the step (j). In the manufacturing method of the wiring board as described in any one of Claims 1-4,
In the step (a), a carrier plate is used as a copper plate, a metal foil is used as a copper foil, and a plurality of metal foils with a carrier having copper foil provided on one surface side of the carrier plate via a release layer is prepared. A method for manufacturing a wiring board. In the manufacturing method of the wiring board as described in any one of Claims 1-5,
In the process of forming a via hole, a via hole is formed in a target insulating layer by a laser,
In the step of forming a via, a via is formed by filling a target via hole with a plating metal.

Images