JP7111314B2 - Printed circuit board and manufacturing method thereof - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to printed circuit boards and methods of manufacturing the same.

2. Description of the Related Art As electronic devices in the IT field, such as mobile phones, have become smaller and more sophisticated, various types of thin printed circuit board structures have been proposed to meet the technical demands.

However, thin printed circuit boards have the problem that it is difficult to ensure rigidity and they are vulnerable to warping. For this reason, various insulating materials have been proposed that can reinforce the rigidity.

Japanese Patent Publication No. 1998-050209

According to one aspect of the present invention, an insulating layer having an opening formed thereon, a circuit pattern disposed in the insulating layer and at least partially exposed by the opening, and a circuit pattern adjacent to the circuit pattern and at least partially exposed by the opening. A printed circuit board is provided that includes a partially exposed sandblasting protective layer formed of a material dissimilar to the circuit pattern.

According to another aspect of the present invention, a step of forming a circuit pattern on one surface of the first insulating layer; forming a layer; laminating a second insulating layer covering the circuit pattern and the sandblasting protective layer; and forming an opening in the second insulating layer by sandblasting to expose the area where the sandblasting protective layer is formed. and removing the sandblasting protective layer to expose the circuit pattern.

1 is a cross-sectional view showing a printed circuit board according to one embodiment of the present invention; FIG. FIG. 4 is a cross-sectional view of a printed circuit board according to another embodiment of the present invention; 1 is a flow chart showing a method of manufacturing a printed circuit board according to an embodiment of the present invention; FIG. FIG. 4 is a diagram for explaining a method of manufacturing a printed circuit board according to an embodiment of the present invention; FIG. 4 is a diagram for explaining a method of manufacturing a printed circuit board according to an embodiment of the present invention; FIG. 4 is a diagram for explaining a method of manufacturing a printed circuit board according to an embodiment of the present invention; FIG. 4 is a diagram for explaining a method of manufacturing a printed circuit board according to an embodiment of the present invention; FIG. 4 is a diagram for explaining a method of manufacturing a printed circuit board according to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE INVENTION Embodiments of a printed circuit board and method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. , and a redundant description thereof will be omitted.

In addition, terms such as "first" and "second" used below are merely identification symbols for distinguishing the same or corresponding components, and the same or corresponding components It is not limited by terms such as.

In addition, in the contact relationship between each component, the term “bond” does not mean only the case where each component is in direct physical contact, and another structure intervenes between each component. It is used as a concept that includes the case where each component is in contact with another configuration.

(printed circuit board)
FIG. 1 is a cross-sectional view showing a printed circuit board according to one embodiment of the present invention. Referring to FIG. 1, a printed circuit board according to one embodiment of the present invention includes an insulation layer 10, circuit patterns 22, 24, and sandblast protection layers 30, 35. As shown in FIG.

The insulating layer 10 electrically insulates the circuit patterns 22,24. The insulating layer 10 can be made of a resin material. The insulating layer 10 may contain a thermosetting resin such as epoxy resin or a thermoplastic resin such as polyimide (PI), and may be formed of prepreg (PPG) or build-up film.

In this embodiment, the insulating layer 10 can be made of a thermosetting resin, which is advantageous in securing rigidity and preventing warpage in a thin printed circuit board.

Openings 15 and 16 may be formed in the insulating layer 10 to expose the inside of the insulating layer 10 , and the circuit patterns 22 and 24 may be partially exposed through the openings 15 and 16 .

Referring to FIG. 1, in this embodiment, the insulation layer 10 can be formed of two layers, the circuit patterns 22 and 24 are formed on the lower first insulation layer 11, and the circuit patterns 22 and 24 are formed on the first insulation layer 11. A second insulating layer 12 covering 24 may be formed. Through hole-shaped openings 15 and 16 exposing portions of the circuit patterns 22 and 24 may be formed in the second insulating layer 12 . At this time, a thermosetting resin having a higher strength than a photosensitive resin can be used for the second insulating layer 12, and the through holes in the second insulating layer 12 can be formed by physical processing such as sandblasting. can be done. Thereby, the second insulating layer 12 can form a solder resist layer that selectively exposes the internal circuit patterns 22 and 24, and has high strength.

Circuit patterns 22 and 24 are formed on the insulating layer 10 . The circuit patterns 22 and 24 are made of metal such as copper and can be formed inside the insulating layer 10 . The circuit patterns 22 and 24 formed inside the insulating layer 10 can be exposed to the outside through openings 15 and 16 formed in the insulating layer 10 at least partially.

Referring to FIG. 1, circuit patterns 22 and 24 are formed on the first insulating layer 11 , the second insulating layer 12 covers the circuit patterns 22 and 24 , and the circuit pattern 22 is entirely disposed inside the insulating layer 10 . , 24 can be formed. Some of the circuit patterns 22 , 24 may include pads exposed by openings 15 , 16 of the second insulating layer 12 . The pad may be a circuit pattern 22 whose top surface is selectively exposed, or a circuit pattern 24 whose top surface and side surfaces are exposed.

The sandblast protection layers 30 and 35 are formed to selectively cover the circuit patterns 22 and 24 during the manufacturing process of the printed circuit board, and are made of a material different from that of the circuit patterns 22 and 24 . In particular, the sandblast protection layers 30,35 can be formed using a material that is more resistant to sandblasting than the circuit patterns 22,24.

The sandblasting protection layers 30 and 35 are formed in a shape to cover the circuit patterns 22 and 24 in the regions where the openings 15 and 16 are formed in the insulating layer 10, and cover the circuit patterns in the process related to the openings 15 and 16 of the insulating layer 10. 22, 24 can be protected.

The sandblast protection layers 30, 35 are mostly removed after forming the openings 15, 16 in the insulation layer 10, but some may remain inside the insulation layer 10. FIG. The sandblast protection layers 30 and 35 remaining inside the insulating layer 10 are at least partially exposed by the openings 15 and 16 and are adjacent to the circuit patterns 22 and 24 .

Referring to FIG. 1, the sandblast protection layers 30, 35 are interposed between the first insulation layer 11 and the second insulation layer 12, or between the circuit patterns 22, 24 and the second insulation layer 12. It may remain in its original form. Also, the sandblast protection layers 30 and 35 may be formed to be exposed from the inner walls of the openings 15 and 16 .

On the other hand, in the present embodiment, the inner walls of the openings 15 and 16 and the cut surfaces of the sandblast protection layers 30 and 35 are shown to match, but the sandblast protection layers 30 and 35 are separated from the inner walls of the openings 15 and 16. It can either protrude or be recessed.

FIG. 2 is a cross-sectional view of a printed circuit board according to another embodiment of the invention.

Referring to FIG. 2, the sandblast protection layers 30', 35' may have a shape exposed only on one side of the inner walls of the openings 15, 16. As shown in FIG. It can have such a form when the sandblasting protection layer is tilted in one direction in the manufacturing process or one sandblasting protection layer is completely removed.

On the other hand, the sandblast protection layers 30, 35 can be formed of metal layers of nickel, titanium and alloys containing these. Also, the sandblast protection layers 30, 35 can be formed by a plurality of metal layers (31 and 32, 36 and 37). Specifically, in this embodiment, a double layer of copper layers 32, 37 and nickel layers 31, 36 or a double layer of copper and titanium can be used as the sandblast protection layers 30, 35. FIG.

Nickel and titanium are materials that are resistant to sandblasting, which is physical processing, so that the circuit patterns 22 and 24 can be prevented from being damaged during the process of forming the openings 15 and 16 . Furthermore, the substance that etches the plated layers of nickel and titanium hardly damages the circuit patterns 22 and 24 formed of dissimilar metals. As a result, after sandblasting, the sandblast protection layers 30 and 35 can be easily removed without damaging the circuit patterns 22 and 24 .

(Manufacturing method of printed circuit board)
FIG. 3 is a flow chart showing a method of manufacturing a printed circuit board according to one embodiment of the present invention, and FIGS. 4 to 8 are for explaining the method of manufacturing a printed circuit board according to one embodiment of the present invention. is a diagram.

A method for manufacturing a printed circuit board according to an embodiment of the present invention includes step S1 of forming a circuit pattern on a first insulating layer, step S2 of forming a sandblast protection layer, and step S3 of laminating a second insulating layer. , a step S4 of forming an opening by sandblasting, and a step S5 of removing the sandblasting protective layer.

In step S<b>1 of forming a circuit pattern on the first insulating layer, a circuit pattern 20 is formed on one surface of the first insulating layer 11 .

Referring to FIG. 4, circuit patterns 22 and 24 can be formed on the first insulating layer 11 as pads exposed in the openings 15 and 16 . For example, a patterning process may be performed after coating a conductive metal material on the first insulating layer 11, or a metal layer may be formed by plating and the patterning process may be performed by selective etching. For the patterning process, a tenting method, a modified semi-additive process (MSAP) method, a semi-additive process (SAP) method, or the like can be used.

In step S2 of forming a sandblast protection layer, sandblast protection layers 30 and 35 are formed to protect the circuit pattern 20 arranged in the area processed by sandblasting. The sandblast protection layers 30 and 35 are formed to cover at least a portion of the circuit pattern 20, that is, to selectively cover the circuit pattern 20 where the openings 15 and 16 are formed on the first insulating layer 11. be. The sandblast protection layers 30 and 35 are made of a material different from that of the circuit pattern 20 . In particular, the sandblast protection layers 30 and 35 can be made of a material that is more resistant to sandblasting than the circuit pattern 20 . Also, the sandblast protection layers 30, 35 formed of a material different from the circuit pattern 20 can be easily removed from the circuit pattern 20 after sandblasting.

Referring to FIG. 5, as an example of the sandblast protection layers 30 and 35, a metal layer can be formed on one surface of the first insulating layer 11 by plating. At this time, when the circuit pattern 20 is formed including copper, the sandblast protection layers 30 and 35 may be formed by plating titanium, nickel, or alloys thereof. Also, the sandblast protection layers 30, 35 can be formed by a plurality of metal layers (31 and 32, 36 and 37). Specifically, in this embodiment, a double layer of copper and nickel or a double layer of copper and titanium can be used as the sandblast protection layers 30,35. Nickel and titanium are materials that are resistant to sandblasting, which is physical processing, so that the circuit pattern 20 can be prevented from being damaged during the process of forming the openings 15 and 16 . Furthermore, the substance that etches the plated layers of nickel and titanium scarcely damages the circuit pattern 20 formed of dissimilar metals. As a result, the sandblast protection layers 30 and 35 can be easily removed without damaging the circuit pattern 20 after sandblasting.

Also, if only the upper surfaces of the pads are exposed to the openings 15 and 16, the sandblast protection layer 30 can be selectively formed only on the upper surfaces of the circuit patterns 22. FIG.

On the other hand, if the side surfaces of the pads are also exposed to the openings 15 and 16, the sandblast protection layer 35 may be formed to cover the top surface and side surfaces of the circuit pattern 24 as well. At this time, the sandblast protection layer 35 can be formed by sputtering. By sputtering, the sandblast protection layer 35 can be easily formed on the circuit patterns having different heights and on the side surfaces of the circuit patterns.

In step S3 of laminating the second insulating layer, the second insulating layer 12 covering the circuit pattern 20 and the sandblast protection layers 30 and 35 is laminated.

Referring to FIG. 6 , a second insulating layer 12 is laminated on the first insulating layer 11 , and the second insulating layer 12 also covers the circuit pattern 20 on the first insulating layer 11 . For example, the second insulating layer 12 can be formed by pressing and laminating a thermosetting resin in a prepreg state toward the first insulating layer 11 .

In step S4 of forming openings by sandblasting, the openings 15 and 16 are formed in the second insulating layer 12 by sandblasting to expose the regions where the sandblasting protection layers 30 and 35 are formed.

Sandblasting is a processing method in which an abrasive material is sprayed from a nozzle to polish or cut the surface of a material. In the past, sand was used as an abrasive, so it was called sand blasting, but today, various particles such as ceramic powder such as alumina (aluminum oxide) or silicon carbide, glass beads, plastic powder, etc. can be used as an abrasive. . Sand blasting includes wet sand blasting in which abrasives and water are mixed and sprayed from nozzles, and dry sand blasting in which only abrasives are sprayed from nozzles using air. There is

Here, in order to protect the unprocessed portions of the second insulating layer 12 during sandblasting, a processing prevention layer 40 can be formed on the second insulating layer 12 to selectively cover the unprocessed regions.

Referring to FIG. 7, the processing prevention layer 40 can be formed by laminating and forming a photosensitive film, and then selectively exposing and developing the photosensitive film. The penetrating regions 45 and 46 of the anti-processing layer 40 expose the regions where the openings 15 and 16 are formed in the second insulating layer 12, ie the regions where the sandblast protection layers 30 and 35 are embedded.

On the other hand, the processing prevention layer 40 can be formed by applying a liquid resin instead of a film. After forming the processing prevention layer 40 , the second insulating layer 12 is processed by sandblasting to form the openings 15 and 16 to expose the sandblast protection layers 30 and 35 .

In step S5 of removing the sandblast protection layer, the sandblast protection layers 30 and 35 are removed to expose the circuit patterns 22 and 24 that will serve as pads. The sandblasting protection layers 30 and 35 can be removed by chemical or physical methods, which are easier depending on the material. For example, when the sandblast protection layers 30 and 35 are made of nickel metal layers, they can be dissolved and removed in a nickel etchant. At this time, since the circuit patterns 22 and 24 made of copper material have corrosion resistance to the nickel etchant, they can be preserved without being damaged.

Referring to FIG. 8, in the sandblast protection layers 30, 35 formed of a copper/nickel double layer, the copper layers 32, 37 are removed by a copper etchant and the nickel layers 31, 36 are removed by a nickel etchant. can be At this time, part of the sandblast protection layers 30 and 35 interposed between the circuit pattern 22 and the second insulation layer 12 or between the first insulation layer 11 and the second insulation layer 12 is not removed. can remain

An embodiment of the present invention has been described above. , deletions, additions, etc., can be variously modified and changed, which are also included in the scope of the invention.

10 insulating layer 11 first insulating layer 12 second insulating layer 15, 16 openings 20, 22, 24 circuit patterns 30, 35 sandblast protection layer

Claims (10)

an insulating layer having an opening;
a circuit pattern disposed within the insulating layer and at least partially exposed by the opening;
a sandblast protection layer adjacent to the circuit pattern, at least partially exposed from the opening, formed of a material different from that of the circuit pattern, and including a plurality of metal layers;
Printed circuit board including. The printed circuit board as claimed in claim 1, wherein the sandblast protection layer is exposed from the inner wall of the opening. 3. The printed circuit board of claim 2, wherein the sandblast protection layer is exposed only on one side of the inner wall of the opening. 4. The printed circuit board of any one of claims 1-3, wherein the plurality of metal layers comprises titanium, nickel and alloys thereof. The sandblast protection layer is
5. A printed circuit board as claimed in any preceding claim, comprising a material more resistant to sandblasting than the circuit pattern. 6. The printed circuit board according to any one of claims 1 to 5, wherein the insulating layer contains a thermosetting resin. forming a circuit pattern on one surface of the first insulating layer;
forming a sandblast protection layer covering at least part of the circuit pattern and made of a material different from that of the circuit pattern;
laminating a second insulating layer covering the circuit pattern and the sandblasting protective layer;
forming an opening in the second insulating layer by sandblasting to expose a region where the sandblasting protective layer is formed;
removing the sandblast protection layer by etching to expose the circuit pattern;
including
Forming the sandblast protection layer includes forming a metal layer on one surface of the first insulating layer by plating,
The method of manufacturing a printed circuit board, wherein removing the sandblast protection layer includes removing the metal layer by etching . 8. The method of manufacturing a printed circuit board according to claim 7, wherein the metal layer comprises titanium, nickel and alloys thereof. The sandblast protection layer is
9. A method of manufacturing a printed circuit board according to claim 7 or claim 8, comprising a material more resistant to sandblasting than the circuit pattern. The step of laminating the second insulating layer includes:
10. A method of manufacturing a printed circuit board according to any one of claims 7 to 9, comprising the step of laminating a thermosetting resin.

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