JP2008277749A - Wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board and its manufacturing method capable of forming a wiring layer by satisfactorily securing an adhesion with a resin layer without requiring a vexatious process of forming an adhesion layer and a seed layer on the resin layer and of removing an unwanted part of these two layers. <P>SOLUTION: The wiring board has the wiring layer comprising the adhesive seed layer of Ni-Cu alloy comprising 20 to 75 wt.% Ni and a remnant Cu, and the Cu layer on it. The wiring board can be manufactured: (A) by forming the Ni-Cu alloy adhesive seed layer by a single process to remove the unwanted part by a single etching after a wiring patterning, or (B) by forming the Ni-Cu alloy adhesive seed layer and the Cu layer on it to collectively pattern them by etching them. The wiring layer of the wiring board is formed by the Ni-Cu alloy comprising the 20 to 75 wt.% Ni and the remnant Cu all over the wiring layer. This can be manufactured by directly forming the Ni-Cu alloy wiring layer on the resin layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiring board and a method for manufacturing the wiring board, and more particularly, to a wiring board including a wiring layer that can ensure adhesion with a resin insulating layer as a base without requiring a complicated process and a method for manufacturing the wiring board.

  Conventionally, in a wiring substrate such as a semiconductor package, when a Cu wiring layer is formed on a resin insulating layer, Ni is formed on the surface of the resin layer in order to ensure adhesion between the resin of the insulating layer and Cu of the wiring layer. First, an adhesion layer made of a metal such as Ti, V, Nb, Ta, Cr, Mo, or W or Cu nitride is formed, and a Cu wiring layer is formed thereon. The wiring formation process will be described by taking the case of using Ni as a typical adhesion layer as an example.

  As shown in FIG. 1A, for example, a resin layer 10 made of epoxy having a thickness of about 50 μm is prepared as an interlayer insulating film of a wiring board.

  As shown in FIG. 1 (2), the surface of the resin layer 10 is cleaned with argon gas plasma, and the Ni adhesion layer 12 and the Cu seed layer 14 are sequentially formed in an argon gas atmosphere of about 0.5 Pa while maintaining a vacuum. It is formed by sputtering. For example, the Ni adhesion layer 12 has a thickness of 50 nm, and the Cu seed layer 14 has a thickness of 500 nm.

  As shown in FIG. 1C, a plating resist pattern 16 is formed on the Cu seed layer 14 by applying a photoresist, pattern exposure, and development.

  As shown in FIG. 1 (4), electrolytic Cu plating is performed using the Ni adhesion layer 12 / Cu seed layer 14 as a power feeding layer, and an electrolytic Cu plating layer 18 is formed on the Cu seed layer 14 exposed in the opening of the plating resist pattern 16. Form.

  As shown in FIG. 1 (5), the plating resist pattern 16 is peeled and removed.

  As shown in FIG. 1 (6), an unnecessary portion of the Cu seed layer 14 exposed by the removal of the plating resist pattern 16 is removed with a sulfuric acid-based etching solution.

  As shown in FIG. 1 (7), an unnecessary portion of the Ni adhesion layer 12 exposed by the removal of the Cu seed layer 14 is removed with a nitric acid-based etching solution. Thereby, the wiring layer 17 having a predetermined pattern composed of the adhesion layer 12, the seed layer 14, and the electrolytic Cu plating layer 18 is completed.

  The Cu wiring layer 17 thus formed is sufficiently secured to the resin layer 10 by the Ni adhesion layer 12.

  However, the two-layer structure of the Ni adhesion layer 12 / Cu seed layer 14 has the following problems [1] and [2].

Problem [1]
The formation of the Ni adhesion layer 12 and the Cu seed layer 14 requires, for example, two targets in the case of sputtering, and may further require two sputtering processing chambers in consideration of the tact of the manufacturing process. Cost increases.

Problem [2]
Since the removal of the Ni adhesion layer 12 and the Cu seed layer 14 must be performed with separate etching solutions, the etching process needs to be performed twice.

  In order to solve these problems, Patent Document 1 proposes a method of forming an adhesion layer with CuN.

Solving Problem [1] A CuN adhesion layer was formed by introducing nitrogen gas using a Cu target and performing reactive sputtering, and the introduction of nitrogen gas was subsequently stopped in the same processing chamber to use the same Cu target. Since the Cu seed layer can be formed on the CuN adhesion layer by performing sputtering, the manufacturing cost does not increase.

Solving Problem [2] The CuN adhesion layer and the Cu seed layer formed thereon can be removed with the same sulfuric acid-based Cu etching solution, so that only one etching process is required.

  However, the proposed method has a problem that the adhesion between the final electrolytic Cu-plated wiring layer and the resin layer is inferior to the two-layer structure of the Ni adhesion layer 12 / Cu seed layer 14.

JP 2003-218516 A

  The present invention does not require a complicated process for forming an adhesion layer and a seed layer on the resin layer and removing unnecessary portions of both layers, and ensures good adhesion with the resin layer and wiring. It is an object of the present invention to provide a wiring board capable of forming a layer and a manufacturing method thereof.

In order to achieve the above object, the wiring board of the first invention is a wiring board having a resin insulating layer and a Cu wiring layer thereon,
A wiring layer comprising a Ni—Cu alloy adhesion layer comprising Ni: 20 to 75 wt% and the balance Cu and a Cu layer thereon is provided on the resin insulation layer.

According to one embodiment, a method of manufacturing a wiring board of the first invention is as follows:
Forming an adhesion layer of the Ni-Cu alloy on the entire area of the wiring layer formation planned region on the resin insulation layer;
Forming a plating resist pattern on the adhesion layer,
Forming a Cu layer by electrolytic plating in the opening of the plating resist pattern, using the adhesion layer as a power feeding layer;
The method includes a step of removing the plating resist pattern, and a step of removing the adhesion layer in a portion exposed by the removal of the plating resist pattern.

Alternatively, the method for manufacturing the wiring board of the first invention, according to another embodiment,
Forming a contact seed layer of the Ni-Cu alloy on the entire surface of the wiring insulating layer formation region on the resin insulation layer;
Forming a Cu layer on the entire surface of the adhesion seed layer;
Forming an etching resist pattern on the Cu layer;
Using the etching resist pattern as a mask, patterning the Cu layer and the adhesion seed layer underneath by etching to form a wiring layer, and removing the plating resist pattern. Features.

Furthermore, in order to achieve the above object, the wiring board of the second invention is:
In a wiring board having a resin insulating layer and a wiring layer thereon,
The wiring layer is formed of a Ni—Cu alloy comprising Ni: 20 to 75 wt% and the balance Cu over the entire thickness of the wiring layer.

The method of manufacturing the wiring board of the second invention is as follows:
Forming a metal layer of the Ni-Cu alloy on the entire surface of the wiring insulating layer formation region on the resin insulation layer;
Forming an etching resist pattern on the metal layer;
Using the etching resist pattern as a mask, the Ni—Cu alloy wiring layer is patterned by etching to form a wiring layer, and the etching resist pattern is removed.

  According to the first invention, by forming the adhesion layer / seed layer, that is, the adhesion seed layer, with the Ni—Cu alloy having a predetermined composition range, the formation of the adhesion layer and the seed layer and the removal of unnecessary portions of these layers are each 1 It is possible to carry out the process once, and at the same time, it is possible to ensure good adhesion between the wiring layer and the resin layer.

  According to the second invention, since the wiring layer itself is directly formed on the resin with a Ni—Cu alloy having a predetermined composition range, it is necessary to separately form an adhesion layer and a seed layer and remove unnecessary portions of these layers. Instead, the wiring layer can be formed by a single treatment while ensuring good adhesion to the resin layer.

[Embodiment 1A]
An example of a preferred embodiment for producing a wiring board according to the first invention will be described.

  As shown in FIG. 2A (1), a resin layer 10 made of epoxy, polyimide, or the like having a thickness of about 50 μm is prepared as an interlayer insulating film of a wiring board.

  As shown in FIG. 2A (2), the surface of the resin is cleaned with an argon plasma of about 0.5 Pa, and a Ni—Cu alloy having a prescribed composition is used in an argon gas atmosphere of about 0.5 Pa while maintaining a vacuum. The close contact seed layer 20 is formed by sputtering. The thickness of the adhesion seed layer 20 is generally about 500 nm, but it is desirable that the thickness is about 100 to 1000 nm in consideration of the case where unevenness is formed on the resin surface.

  As shown in FIG. 2A (3), a plating resist pattern 16 is formed on the Ni—Cu alloy adhesion seed layer 20 by application of a photoresist, pattern exposure, and development.

  As shown in FIG. 2A (4), electrolytic Cu plating is performed using the Ni—Cu alloy adhesion seed layer 20 as a power feeding layer, and a thickness is formed on the Ni—Cu alloy adhesion seed layer 20 exposed in the opening of the plating resist pattern 16. An electrolytic Cu plating layer 18 of about 20 μm is formed.

  As shown in FIG. 2A (5), the plating resist pattern 16 is peeled and removed.

  As shown in FIG. 2A (6), the unnecessary portion of the Ni—Cu alloy adhesion seed layer 20 exposed by the peeling of the plating resist pattern 16 is removed with a sulfuric acid aqueous solution as a Cu etching solution. Since the thickness of the electrolytic Cu plating layer 18 is larger than the thickness of the Ni—Cu alloy adhesion seed layer 20, problems such as disconnection due to this etching do not occur. As a result, a wiring layer 19 having a predetermined pattern, which is typically composed of the adhesion seed layer 20 and the electrolytic Cu plating layer 18 of line and space (L / S) = 20 μm / 20 μm, is completed. Finally, the insulation between the wiring patterns is confirmed, and the wiring formation process is completed.

  According to the present embodiment, the adhesion seed layer serving as the adhesion layer and the seed layer can be formed on the resin layer in one processing step, and unnecessary portions are removed by one etching process. At the same time, good adhesion between the wiring layer and the resin layer can be secured.

[Embodiment 1B]
Another example of a preferred embodiment for producing a wiring board according to the first invention will be described.

  As shown in FIG. 2B (1), a resin layer 10 made of epoxy, polyimide, or the like having a thickness of about 50 μm is prepared as an interlayer insulating film of a wiring board.

As shown in FIG. 2B (2), the surface of the resin is cleaned with an argon plasma of about 0.5 Pa, and a Ni—Cu alloy having a prescribed composition is used in an argon gas atmosphere of about 0.5 Pa while maintaining a vacuum. The close contact seed layer 20 is formed by sputtering. The thickness of the adhesion seed layer 20 is generally about 500 nm, but it is desirable that the thickness is about 100 to 1000 nm in consideration of the case where unevenness is formed on the resin surface.
The steps so far are the same as those in Embodiment 1A, and the following steps are different.

  As shown in FIG. 2B (3), electrolytic Cu plating is performed using the Ni—Cu alloy adhesion seed layer 20 as a power feeding layer, and an electrolytic Cu plating layer 18 having a thickness of about 20 μm is formed on the Ni—Cu alloy adhesion seed layer 20. To do.

  As shown in FIG. 2B (4), an etching resist pattern 16 is formed by applying a photoresist, pattern exposure, and development.

  As shown in FIG. 2B (5), the electrolytic Cu plating layer 18 exposed in the opening of the etching resist pattern 16 and the Ni-alloy adhesion seed layer 20 thereunder are bundled together with a sulfuric acid aqueous solution as a Cu etching solution. To remove.

  As shown in FIG. 2B (6), the etching resist pattern 16 is peeled and removed. As a result, a wiring layer 19 having a predetermined pattern, which is typically composed of the adhesion seed layer 20 and the electrolytic Cu plating layer 18 of line and space (L / S) = 20 μm / 20 μm, is completed. Finally, the insulation between the wiring patterns is confirmed, and the wiring formation process is completed.

  According to the present embodiment, an adhesion seed layer serving as an adhesion layer and a seed layer can be formed on the resin layer in a single processing step, and this adhesion seed layer and an electrolytic Cu plating layer thereon are further formed. Can be patterned by a single etching to form a wiring layer composed of these two layers, and at the same time, good adhesion between the wiring layer and the resin layer can be secured.

  In this embodiment, the electrolytic Cu plating layer 18 having a thickness of about 20 μm is formed in the step described with reference to FIG. 2B (3). Instead, a Cu layer 18 having a thickness of about 2000 nm is formed by sputtering. May be. There is no change in other processes due to this change.

  In the above modification, the Ni—Cu alloy adhesion seed layer 20 in FIG. 2B (2) and the Cu layer 18 in FIG. 2b (3) can be formed in the same sputtering apparatus. Yes, the entire wiring formation process can be simplified.

[Embodiment 2]
An example of a preferred embodiment for producing a wiring board according to the second invention will be described.

  As shown in FIG. 3A, a resin layer 10 made of epoxy or polyimide having a thickness of about 50 μm is prepared as an interlayer insulating film of a wiring board.

  As shown in FIG. 3 (2), the resin surface is cleaned with an argon plasma of about 0.5 Pa, and a Ni—Cu alloy having a prescribed composition is used in an argon gas atmosphere of about 0.5 Pa while maintaining a vacuum. A metal layer 25 is formed by sputtering. The thickness of the metal layer 25 is, for example, about 2000 nm.

  As shown in FIG. 3C, an etching resist pattern 16 is formed on the metal layer 25 by applying a photoresist, pattern exposure, and development.

  As shown in FIG. 3D, the exposed portion of the metal layer 25 from the etching resist pattern 16 is removed with a sulfuric acid-based aqueous solution that is a Cu etching solution.

  As shown in FIG. 3 (5), the etching resist pattern 16 is peeled and removed. As a result, the wiring layer 26 having a predetermined pattern, which is typically made of the Ni—Cu alloy 25 of line and space (L / S) = 20 μm / 20 μm, is completed. Finally, the insulation between the wiring patterns is confirmed, and the wiring formation process is completed.

  According to the present embodiment, a wiring layer made of a Ni—Cu alloy can be formed directly on the resin layer without the need for separate adhesion layers and seed layers. While simplifying, good adhesion between the wiring layer and the resin layer can be secured.

  By the method of Embodiment 1A, Ni—Cu alloy adhesion seed layers having various compositions were formed on the resin layer, and an electrolytic Cu wiring layer was formed thereon, and the peel strength was measured. The measurement sample was produced by the following procedures (1) to (5).

  (1) An epoxy resin having a thickness of about 50 μm was laminated as an interlayer insulating film on a printed circuit board to which a copper foil was bonded.

  (2) The resin surface was cleaned with argon gas plasma of about 0.5 Pa.

  (3) Ni—Cu alloy films (adhesive seed layers) of various compositions were formed to a thickness of 500 nm by sputtering in an argon gas atmosphere of about 0.5 Pa while keeping the vacuum from (2) above.

  (4) An electrolytic Cu plating film was formed to a thickness of 20 μm on the Ni—Cu alloy film.

  (5) After forming an etching resist pattern on the Ni—Cu alloy film by applying a photoresist, pattern exposure, and developing with a sodium carbonate solution, the Ni—Cu alloy film is etched and the etching resist pattern is peeled and removed to give a width of 1 cm. A wiring layer made of an electrolytic Cu plating film was formed.

  Next, the peel strength test of the wiring layer obtained above was performed.

  The substrate was fixed on the stage of a tensile tester, a 1 cm wide electrolytic Cu plating film (wiring layer) was pulled in the vertical direction, and the tension when peeling from the resin layer occurred was measured as the peel strength.

  FIG. 4 shows the relationship between the Ni content of the Ni—Cu alloy film (adherent seed layer) and the peel strength. The right end of the figure, that is, the state where the Ni content is 100 wt% corresponds to the peel strength in the case of the conventional Ni adhesion layer / Cu seed layer.

  As shown in the figure, a peel strength of 0.70 to 0.77 kgf / cm was obtained when the Ni content was 20 wt% or more. This is a good value equivalent to the peel strength when a conventional Ni adhesion layer / Cu seed layer is used.

When the peeling form is observed, if the Ni content is less than 20 wt%, peeling occurs at the interface between the electrolytic Cu plating film and the Ni—Cu alloy film, and peel peeling in this case is low. On the other hand, when the Ni content is 20 wt% or more, all peeling is caused by cohesive peeling in the resin layer, and the peel strength is determined by the breaking strength of the resin layer itself, so that a stable high peel strength is obtained. can get. This peeling form was the same as the case of using the conventional Ni adhesion layer / Cu seed layer.
When the Ni content exceeds 75 wt%, etching with a sulfuric acid aqueous solution that is a Cu etching solution becomes difficult. Therefore, the Ni content is suitably 20 to 75 wt%.

  According to the present invention, good adhesion to the resin layer can be ensured without the need for complicated processes for forming an adhesion layer and a seed layer on the resin layer and removing unnecessary portions of both layers. A wiring board capable of forming a wiring layer and a method for manufacturing the same are provided.

  In particular, according to the first invention, an adhesion seed layer that serves as an adhesion layer and a seed layer can be formed on the resin layer in a single processing step, and unnecessary portions of both layers can be removed once. Etching can be performed, and at the same time, good adhesion between the electrolytic copper-plated wiring layer and the resin layer can be ensured.

  Furthermore, according to the second invention, a wiring layer made of a Ni—Cu alloy can be formed directly on the resin layer without the need for a separate adhesion layer and seed layer. It is possible to ensure good adhesion between the wiring layer and the resin layer while greatly simplifying the process.

It is sectional drawing which shows typically the formation method of the electrolytic Cu plating wiring layer using the conventional Ni adhesion layer / Cu seed layer. It is sectional drawing which shows typically the formation method of the wiring layer which consists of a Ni-Cu alloy contact | adherence seed layer and the electrolytic Cu plating layer on it on the resin layer by one Embodiment of 1st invention. It is sectional drawing which shows typically the formation method of the wiring layer which consists of a Ni-Cu alloy contact | adherence seed layer and Cu layer on it on a resin layer by other embodiment of 1st invention. It is sectional drawing which shows typically the method of forming a Ni-Cu alloy wiring layer directly on a resin layer by 2nd invention. It is a graph which shows the relationship between the peel strength of the electrolytic Cu plating wiring layer formed by 1st invention, and Ni content rate of a Ni-Cu alloy adhesion seed layer.

Explanation of symbols

10 Resin layer (interlayer insulation film)
12 Ni adhesion layer 14 Cu seed layer 16 Photoresist pattern 17 Wiring layer 18 Electrolytic Cu plating layer 19 Wiring layer 20 Adhesion seed layer made of Ni-Cu alloy 25 Metal layer made of Ni-Cu alloy 26 Wiring layer

Claims (5)

In a wiring board having a resin insulating layer and a Cu wiring layer thereon,
A wiring board comprising a Ni—Cu alloy adhesion seed layer made of Ni: 20 to 75 wt% and the balance Cu, and a Cu layer thereon provided on the resin insulation layer. A method of manufacturing the wiring board according to claim 1,
Forming a contact seed layer of the Ni-Cu alloy on the entire surface of the wiring insulating layer formation region on the resin insulation layer;
Forming a plating resist pattern on the adhesion seed layer;
A step of forming a Cu layer by electrolytic plating in the opening of the plating resist pattern using the adhesion seed layer as a power feeding layer;
A method for manufacturing a wiring board, comprising: a step of removing the plating resist pattern; and a step of removing the adhesion seed layer exposed by removing the plating resist pattern. A method of manufacturing the wiring board according to claim 1,
Forming a contact seed layer of the Ni-Cu alloy on the entire surface of the wiring insulating layer formation region on the resin insulation layer;
Forming a Cu layer on the entire surface of the adhesion seed layer;
Forming an etching resist pattern on the Cu layer;
Using the etching resist pattern as a mask, patterning the Cu layer and the adhesion seed layer underneath by etching to form a wiring layer, and removing the plating resist pattern. A method for manufacturing a wiring board. In a wiring board having a resin insulating layer and a wiring layer thereon,
A wiring board, wherein the wiring layer is formed of a Ni-Cu alloy comprising Ni: 20 to 75 wt% and the balance Cu over the entire thickness of the wiring layer. A method for producing a wiring board according to claim 4, comprising:
Forming a metal layer of the Ni-Cu alloy on the entire surface of the wiring insulating layer formation region on the resin insulation layer;
Forming an etching resist pattern on the metal layer;
A method of manufacturing a wiring board, comprising: forming a wiring layer by patterning the metal layer of the Ni—Cu alloy by etching using the etching resist pattern as a mask; and removing the etching resist pattern. .

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