JP2902849B2 - Printed circuit board manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed circuit board, and more particularly to a print suitable for improving the adhesion between an interlayer insulating film and a conductive circuit and an insulating film when a multilayer wiring printed circuit board is manufactured by a build-up method. The present invention relates to a method for manufacturing a substrate.

[0002]

2. Description of the Related Art Conventionally, in order to improve the adhesion of an interlayer insulating film when forming a multilayer wiring printed board by laminating wiring layers in multiple layers by a build-up method, for example, irregularities are formed on the surface of the interlayer insulating film by a unit. There is known a method of increasing the surface area per area to have an anchor effect. The following are two typical examples.

First, the first example will be described with reference to the cross-sectional view of the manufacturing process shown in FIG. Step (a): The first interlayer insulating film 3 is printed on the printed circuit board 1 on which the conductive circuit pattern 2 is formed. Step (b): forming a swelling layer 4 on the surface of the interlayer insulating film 3. Step (c): The swelling layer 4 formed in step (b) is subjected to a surface treatment with a roughening solution composed of, for example, a mixed solution of chromic acid and sulfuric acid to form a roughened surface body 5. Step (d): The second interlayer insulating film 3a is printed on the surface other than the predetermined region 10 where the conductive circuit pattern is to be formed, and then the catalyst 6 is attached. Step (e): A conductive circuit pattern is formed by copper plating 7. Thereafter, a third interlayer insulating film 3b is formed, and steps (a) to (c) are performed.
Step (e) is repeated for the required number of layers.

Next, a second example will be described. A powdery, granular, fibrous, acicular or a mixture thereof is mixed into an interlayer insulating film, and the filler is projected on the surface of the interlayer insulating film. There is known a method of forming an uneven surface and increasing the surface area per unit area to have an anchor effect. The steps of this manufacturing method will be described below. Step (a): An interlayer insulating film containing a powdery, granular, fibrous, acicular or a mixture thereof is printed on a printed circuit board on which a conductive circuit pattern is formed. The surface of the printed insulating film has an uneven surface formed by the filler. The printing method is the same as that in the step (d) of the first example, and the interlayer insulating film is printed on the other surface except for the portion where the conductive circuit pattern is to be formed. Step (b): Next, the catalyst 6 is attached. Step (c): A conductive circuit pattern is formed by copper plating. Thereafter, the steps (a) to (c) are repeated for the required number of layers. In addition, as a technique related to a technique of mixing this kind of filler into an interlayer insulating film, for example, Japanese Patent Application Laid-Open No. Hei.
No. 4 gazette.

[0005]

However, according to the first conventional example, the mixed solution of chromic acid and sulfuric acid used as a roughening solution for roughening the swelling layer 4 becomes a strong acid, so that an interlayer insulating film is formed. However, there is a disadvantage that the epoxy resin, which is a component of the above, is excessively dissolved. For this reason, it is difficult to obtain a uniform roughened surface with many roughening irregularities. As a result, as shown in step (e) of FIG. 1, a copper plating blister 8 is formed, and the adhesion between the interlayer insulating film 3 and the copper plating conductive circuit 7 is extremely poor (peel strength: at least 0,1). 1 kg / cm). Along with this, there is the inconvenience that the process control such as swelling and roughening conditions must be strict.

According to the second conventional example, the filler projecting from the surface of the interlayer insulating film is not completely exposed, but is coated on the interlayer insulating film of about 0.1 to 1.0 μm. As in the first example, there is a problem that the reliability is poor (peel strength: at least 0.1 kg / cm) in terms of adhesion between the interlayer insulating film and the conductive circuit and between the interlayer insulating films.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problem of the adhesion pointed out in the above-mentioned prior art, and to improve the adhesion between interlayer insulating films and between the interlayer insulating film and the conductive circuit pattern. Improves insulation properties of insulating film
It is an object of the present invention to provide an improved method of manufacturing a printed circuit board for manufacturing a high-density printed circuit board having a highly reliable fine line pattern circuit by a build-up method.

[0008]

The object of the present invention is as follows .
On the surface of the printed circuit board on which the conductive circuit pattern
The process of printing an interlayer insulating film and the lithography technology
Patterning the interlayer insulating film to form at least the conductive
Exposing a part of the circuit pattern and forming a circuit on the interlayer insulating film.
Forming an opening for connection of the patterning
Including an interlayer insulating film with an opening for circuit connection
And applying a catalyst on the plate, the removing of the catalyst on the interlayer insulating film by polishing the surface of the interlayer insulating film
A polishing process leaving the catalyst selectively in the opening, the opening
Forming a second conductive circuit pattern by applying a copper plating to a catalyst remaining region on a substrate including the substrate, and manufacturing the printed circuit board by a build-up method in which these steps are repeated a plurality of times in accordance with the number of layers. A method, wherein the interlayer insulation is provided.
A filler is dispersed in the film in advance, and after curing the insulating film, at least the filler protruding and buried in the surface layer is dissolved and removed with a solvent to form irregularities on the surface. the method of manufacturing a printed circuit board comprising a step of increasing the surface area is achieved.

The material of the filler is selected in consideration of the fact that the filler is a substance which maintains a granular shape during the formation of the interlayer insulating film and can be easily dissolved in an acid or alkali solution serving as a solvent after curing the insulating film. There must be. In addition, in the case of industrial implementation, it is difficult to obtain the substance unless it is a substance having high versatility, and lacks mass productivity. Therefore, hydroxide,
Inorganic fillers such as carbonates and sulfates are used.Examples of hydroxides include aluminum hydroxide, magnesium hydroxide, and basic magnesium carbonate.Examples of carbonates include calcium carbonate and magnesium carbonate. There are (sulfite) salts such as calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite and the like. Among them, calcium carbonate exhibits a stable performance with an increase in the surface area of the interlayer insulating film, and is excellent in handleability and economy. The average particle size of these fillers is 2 to 10 μm.
m, more preferably 3 to 6 μm, and particularly preferably 4 to 5 μm.

Solvents that dissolve the filler under severe conditions are not preferable because they impose a load on the surface treatment conditions. Therefore, the acidic solution is H
Cl, H ₂ SO ₄ , and NaOH solution are preferable as the alkaline solution. It is also necessary to consider that the wastewater treatment is easy and inexpensive, and HCl is particularly preferable.

The conductive circuit pattern laminated on the interlayer insulating film is preferably a two-layer conductor formed by nickel plating as a base pattern and copper plating thereon. A practically preferred thickness of nickel plating is 0.5 to 5.0 μm, and a thickness of copper plating is 1.0 to 5 μm.
0 μm. Since the nickel plating base is composed of denser plating particles than copper plating, the surface does not become flat following the surface roughening of the interlayer insulating film. Therefore, the adhesion between the interlayer insulating film and the conductive circuit pattern is not hindered. Further, when the nickel plating is 0.5 μm or less, the surface of the interlayer insulating film becomes rough plating, which adversely affects the adhesion between the interlayer insulating film and the conductive circuit pattern formed by copper plating. Therefore, as described above, the thickness of the nickel plating is preferably 0.5 μm or more, and the nickel plating solution is more expensive than the copper plating solution. 0-2.0 μm
Becomes

The amount of the filler dispersed in the interlayer insulating film is preferably 70 to 100 parts by weight. If the amount is less than 70 parts by weight, it is difficult to form a dense roughened surface, and the interlayer insulating film is easily peeled off. Further, if it exceeds 100 parts by weight, the amount of the filler is too large, so that the roughened surface body when dissolved with a solvent becomes smooth, and the adhesion between interlayer insulating films is poor. Therefore, 70 parts by weight or more is preferable, and more preferably 80 to 90 parts by weight.
Good by weight.

The solvent for dissolving the filler is preferably a solvent capable of dissolving the filler without deteriorating the interlayer insulating film, and the acidic solution may be, for example, 2.0 to 5.0 wt% H.
Cl or 0.5～3.0Wt% solution of H ₂ SO _4, preferably Na0H solution 2.5～5.0Wt% as alkaline solution. It is important to select the solvent to be used depending on the type of the filler. In the case of calcium carbonate, HCl and H ₂ SO ₄ are suitable, and in the case of aluminum hydroxide, NaOH is suitable. In the case of HCl, the preferred concentration is 2.0 wt% or more, and more preferably 3.0 to 3.0 wt%.
4.0 wt% is good. In the case of H ₂ SO _4, the content is preferably 0.5 wt% or more, and more preferably 1.0 to 2.0 wt%.
0 wt% is good. In the case of NaOH, the content is preferably 2.5% by weight or more, and more preferably 3.0 to 4.0%.
wt% is good.

It is desirable that the material constituting the interlayer insulating film has not only heat resistance but also electroless metal plating resistance. The deposition rate of electroless copper plating for forming a conductive circuit pattern is generally lower than that of electroless nickel plating (electroless copper plating is about 1/3 of nickel plating).
Speed). Therefore, in order to obtain the required plating thickness, it must be immersed in an environment of high temperature and high pH for a long time (about 10 hours depending on the specifications of the printed circuit board of the target product). Therefore, it is necessary to use a strong interlayer insulating film that does not deteriorate its properties as an interlayer insulating film even in these severe situations. From this viewpoint, typical resins practically used include, for example, epoxy resins and polyimide resins.

Here, the means for achieving the object of the present invention will be described more specifically. The object of the present invention is to provide an interlayer insulating film on a surface of a printed circuit board on which a first conductive circuit pattern is provided.
Printing process and the interlayer insulation by lithography technology
Patterning the film to at least the conductive circuit pattern
A part for exposing a circuit connection opening in the interlayer insulating film.
Forming a, for the patterned circuit connection
And applying a catalyst on a substrate comprising an interlayer insulating film in which an opening is formed, the catalyst in the opening by removing the catalyst on the interlayer insulating film by polishing the surface of the interlayer insulating film
A polishing step of selectively leaving, touch on the substrate including the opening
Forming a second conductive circuit pattern by applying copper plating to the remaining medium region, and manufacturing the printed circuit board by a build-up method in which these steps are repeated a plurality of times in accordance with the number of layers. , The first conductive circuit pattern
There in the step of printing an interlayer insulation film disposed the surface of the printed circuit board, and printed <br/> interlayer insulating film of a heat resistant resin having dispersed in advance filler, polishing the surface of the interlayer insulating film
It said opening to remove the catalyst on the interlayer insulating film by
After the polishing step that selectively leaves the catalyst in the part,
The filler protruding and buried in the surface layer of the film is dissolved and removed with a solvent to form irregularities on the surface to increase the surface area.
Steps are added, and catalyst remains on the substrate including the opening.
Copper plating is applied to the region to form a second conductive circuit pattern
That step, the pretreatment step involves activation of the catalyst, a base plating process by electroless nickel plating, the manufacturing method of the printed substrate formed constituted by the electroless copper plating step of laminating the copper thereon Is achieved.

The step of polishing the surface area of the interlayer insulating film other than forming the conductive circuit pattern in the subsequent plating step to remove the catalyst includes, for example, a cloth, a brush, a honing It is desirable to perform mechanical polishing such as

[0017]

Since the filler is dispersed in the interlayer insulating film formed on the surface of the printed circuit board on which the conductive circuit pattern is provided, at least the filler in the surface layer portion is selectively obtained by performing a surface treatment with a solvent. And a uniform and dense roughened surface is formed on the surface layer. This roughened surface body improves the adhesion between the interlayer insulating film and the conductive circuit pattern, and between the interlayer insulating film and the conductive circuit pattern. In particular, when the surface of the interlayer insulating film is subjected to a mechanical polishing process such as a process of polishing the brush while spraying a solution containing a rag, a brush, and an abrasive (referred to as honing), When filler is easier dissolution of the filler for projecting
In both cases, the catalyst other than the openings is removed .

[0018]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional process diagram illustrating an example of a method of manufacturing a printed circuit board according to the present invention.
According to (h), the contents will be sequentially described.

Step (a): A conductive circuit pattern 2 is formed on the copper-clad laminate 1. A first interlayer insulating film 3 containing a carbonate filler is printed on the entire surface by spraying, roller coating, screen coating or the like. In addition, a heat-resistant resin such as an epoxy resin or a polyimide resin is used as an insulating material of the interlayer insulating film, and a carbonate having a mean particle size of 3 to 6 μm is used as a filler. 9
0 parts by weight were well dispersed.

Step (b): Using a mask having a predetermined pattern, the interlayer insulating film 3 was patterned by a well-known lithography technique as shown in the figure. That is, after the mask is brought into close contact with the mask, exposure is performed by irradiating ultraviolet light at 400 to 800 mj / cm ² using an exposure machine equipped with an ultra-high pressure mercury lamp, and further, an organic solvent such as 1,1,1-trichloroethane is removed. The unexposed portion is dissolved and removed as a developer and developed. The first interlayer insulating film 3 thus patterned is cured by heat treatment. In the figure, reference numeral 2a denotes a land portion. The upper insulating film is removed for circuit connection, and a part of the conductive circuit pattern 2 is exposed. Reference numeral 2b denotes a circuit pattern portion covered with the insulating film 3. Next, it is immersed in a solution containing a plating catalyst 6 (a colloid of Pd-Sn), and is fixed to the substrate and the surface of the conductive circuit pattern, so that the deposition reaction of Ni plating performed in a later step can be easily performed.

Step (c): The surface of the first-layer interlayer insulating film 3 patterned in the previous step is polished by a honing process,
The catalyst 6 is removed and the filler on the surface of the interlayer insulating film is exposed. Thereafter, 2.0 to 5.0 wt% H at 15 to 20 ° C.
The exposed surface layer filler is dissolved and removed by immersion in a Cl solution for 1 to 2 minutes.

Step (d): As a pretreatment for electroless Ni plating, a degreasing treatment with an inorganic acid (using a degreasing solution manufactured by Okuno Pharmaceutical Co., Ltd., trade name "ICP Clean 91") and an activity of an inorganic acid system Solution (also trade name "ICP Axela")
After performing the surface treatment of the catalyst in step (c) as shown in the drawing.
Then, 1.0 μm of the electroless Ni plating 9 is selectively deposited in the region where the catalyst 6 is left (the region where the honing treatment has not been performed) (the same electroless Ni plating solution is used under the trade name of “ICP Nicolon”).

Step (e): Electroless copper plating 7 on Ni plating 9 using a well-known electroless copper plating solution of Company S
Is precipitated by 20 μm. This completes the formation of the first-layer conductive circuit pattern.

Step (f): First, the second-layer interlayer insulating film 3
a is printed in the same manner as in the step (a). Next, patterning of the interlayer insulating film 3a and application of the catalyst 6 are performed in the same manner as in the step (b).

Step (g): The surface catalyst is polished and removed by a honing process as shown in the drawing in the same manner as in the step (c) to expose the filler on the surface of the interlayer insulating film 3a, and HCl is added.
The exposed surface layer of the filler is dissolved and removed by immersion in the solution.

Step (h): The above steps (d) and (e)
And electroless Ni plating 9a and electroless copper plating 7a are performed on predetermined regions. This completes the formation of the second-layer conductive circuit pattern as shown.

Thereafter, by repeating the above steps (a) to (e) for the required number of layers, a laminated printed board built up to a desired number of layers can be realized.

FIG. 3 shows that the above steps (a) to (e) are further repeated one cycle after the step (h).
The printed circuit board has a three-layer structure including a third interlayer insulating film 3b, electroless Ni plating 9b, and electroless copper plating 7b.

In the multilayer printed circuit board thus obtained, the adhesion between the interlayer insulating film 3 and the conductive circuit and the interlayer insulating film, that is, the peel strength is improved more than before, and the reliability of each connection portion is improved. It has been greatly improved.

Similar results were obtained when calcium sulfate was used instead of the above carbonate as the filler.

[0031]

As described above, the intended object has been achieved by the present invention. That is, since a uniform and dense roughened surface is formed on the surface of the interlayer insulating film of the printed circuit board of the present invention, it is structurally adherent to the interlayer insulating film or conductive circuit pattern laminated thereon. That is, the peel strength is remarkably improved. Therefore, the conductive circuit pattern on the interlayer insulating film can be thinned, so that a higher-density wiring can be formed.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional process diagram showing an example of a conventional printed circuit board manufacturing process.

FIG. 2 is a schematic cross-sectional process diagram showing a process of manufacturing a printed circuit board according to an embodiment of the present invention.

FIG. 3 is a completed sectional view of a printed circuit board having a three-layer structure according to an embodiment of the present invention.

[Explanation of symbols]

1 ... a copper-clad laminate formed with a circuit, 2 ... a conductive circuit pattern, 2a ... a land portion,
2b: circuit pattern portion, 3: interlayer insulating film (first
Layer), 3a ... interlayer insulating film (second layer), 3
b: interlayer insulating film (third layer), 4: swelling layer, 5: roughened surface, 6:
Catalyst, 7: Copper plating (first layer), 7a
... copper plating (second layer), 7b ... copper plating (third layer),
8: Copper plating blister, 9: Ni plating (first layer), 9a: Ni plating (second layer)
Layer), 9b: Ni plating (third layer), 10: Area where conductive circuit pattern is to be formed.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuo Hamaoka 216 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Hitachi, Ltd. Information Communication Division (56) References JP-A-2-188992 (JP, A) JP-A-61-252698 (JP, A) JP-A-3-171794 (JP, A) JP-A-63-153894 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05K 3 / 46 H05K 3/38

Claims (2)

(57) [Claims] A step of printing an interlayer insulating film on a surface of a printed circuit board on which a first conductive circuit pattern is provided ;
The interlayer insulating film is patterned by
At least part of the conductive circuit pattern
Forming an opening for circuit connection in the inter-insulating film ;
And applying a catalyst on a substrate comprising a patterned inter-layer insulating film having an opening formed for connecting circuits, the opening of the interlayer insulating film surface to remove the catalyst on the interlayer insulating film by polishing the a polishing process leaving the catalyst selectively in parts, copper plating catalyst remaining region on the substrate including the opening
Forming a second conductive circuit pattern, and repeating the steps a plurality of times in accordance with the number of laminations by a build-up method, wherein the interlayer insulating film Is preliminarily dispersed filler, and after curing this insulating film, at least the filler protruding and buried in the surface layer portion is dissolved and removed with a solvent,
A method for manufacturing a printed circuit board, comprising a step of increasing surface area by forming irregularities on a surface. A step of printing an interlayer insulating film on a surface of the printed circuit board on which the first conductive circuit pattern is provided ;
The interlayer insulating film is patterned by
At least part of the conductive circuit pattern
Forming an opening for circuit connection in the inter-insulating film ;
And applying a catalyst on a substrate comprising a patterned inter-layer insulating film having an opening formed for connecting circuits, the opening of the interlayer insulating film surface to remove the catalyst on the interlayer insulating film by polishing the a polishing process leaving the catalyst selectively in parts, copper plating catalyst remaining region on the substrate including the opening
Alms and forming a second conductive circuit pattern, there these steps a method of making a printed circuit board manufacturing in the build-up method is repeated multiple times commensurate with the number of laminated layers, the first conduction in the step of printing an interlayer insulating film on the surface of the printed circuit board on which a circuit pattern is arranged to print an interlayer insulating film in the heat-resistant resin is dispersed in advance filler, by polishing the surface of the interlayer insulating film The interlayer insulating film
The upper catalyst is removed and the catalyst is selectively left in the opening.
After the polishing step, the filler protruded and buried in the surface portion of the interlayer insulating film is dissolved and removed with a solvent to form irregularities on the surface.
Forming and increasing the surface area.
Copper plating is applied to the catalyst remaining area on the substrate including the opening, and the second
A step of forming a conductive circuit pattern, and constituted by a pretreatment step comprising the activation of the catalyst, a base plating process by electroless nickel plating, an electroless copper plating step of laminating the copper thereon Manufacturing method of printed circuit board.