KR20100010169A

KR20100010169A - Multi-layer printed circuit board and manufacturing method thereof

Info

Publication number: KR20100010169A
Application number: KR1020080071040A
Authority: KR
Inventors: 박은정
Original assignee: 박은정
Priority date: 2008-07-22
Filing date: 2008-07-22
Publication date: 2010-02-01

Abstract

PURPOSE: A multilayer printed circuit board and a manufacturing method thereof are provided to simplify a manufacturing process by directly irradiating a CO2 laser to an insulation resin. CONSTITUTION: An insulation resin is compressed on a copper foil with a press(S1). A hole is formed on the insulation resin by irradiating a CO2 laser(S2). A surface process is performed to increase surface roughness of the insulation resin(S3). A copper plating layer is formed on the surface and the hole of the insulation resin(S4). A circuit pattern is formed on the copper plating layer by an etching process(S5). The thickness of the copper plating layer is 10 to 20 um.

Description

Multi-layer printed circuit board and manufacturing method thereof

The present invention relates to a multilayer printed circuit board and a method for manufacturing the same, and more particularly, to shorten the manufacturing process of the multilayer printed circuit board.

There are many types of printed circuit boards, and they are classified into rigid printed circuit boards and flexible printed circuit boards. In addition, it is classified into a multilayer printed circuit board laminated in several layers and a single-sided or double-sided printed circuit board. Multi-layered printed circuit board is a printed circuit board configured to be electrically connected between layers by constructing through-holes after forming circuit patterns in several layers as the complexity of the circuit increases. Therefore, various techniques for forming a through hole and plating a hole for electrical conduction between layers have been developed.

There are several pre-registered patents related to this, and one example thereof is a 'through-hole forming method of a printed circuit board using a laser' disclosed in Republic of Korea Patent No. 0434072.

However, in the method of manufacturing a printed circuit board such as the above-mentioned invention, as the circuit layer increases, the entire board becomes thicker, and a manufacturing method is complicated because a drill process or a laser process for forming a through hole through a dielectric substrate is used. As the manufacturing time is long, the manufacturing process becomes inefficient and the production cost is also increased.

As shown in FIG. 1, in a method of manufacturing a multilayer circuit board, which is generally used, a circuit pattern is formed on a copper foil 15 attached to a base substrate 10, and an insulating resin 17 for interlayer adhesion is formed on an upper surface of the circuit pattern. Attach. Subsequently, in order to construct the through hole, first, the upper exposure copper foil 13 is completely removed by design size by irradiating with a conformal exposure, development, corrosion process or UV laser. Subsequently, the insulating resin 17 formed between the copper foil layers is removed by using a CO 2 laser irradiation method, and copper plating is performed to form electrical plating layers 19 for electrical conduction between the copper foil layers.

The general method for manufacturing a multilayer circuit board as described above is complicated in the manufacturing process is divided into several steps, thereby increasing the manufacturing cost by manpower, equipment and materials required for the process.

The present invention provides a multilayer printed circuit board and a method for manufacturing the same, which simplifies the manufacturing process of the multilayer printed circuit board and reduces manufacturing costs, enables the implementation of a fine circuit pattern, and reduces the thickness of the entire substrate. It is intended to provide a method of manufacturing the same.

According to the present invention, in the method of manufacturing a multilayer printed circuit board, the step of pressing the insulating resin for interlayer adhesion to the copper foil; Irradiating a laser on the surface of the insulating resin to form holes; Performing a surface treatment process on the surface of the insulating resin in which the holes are formed; Copper plating the surface of the insulating resin and the hole to form a copper plating layer; And forming a circuit pattern on the copper plating layer.

The surface treatment process is preferably performed to increase the roughness by spraying alkaline chemicals.

In addition, the insulating resin for interlayer adhesion is pressed onto the copper foil, and a hole is formed by irradiating a laser on the surface of the insulating resin, and the surface of the insulating resin is subjected to a surface treatment process, and copper plating is performed on the insulating resin surface and the hole. A plating layer is formed, and a circuit pattern is formed in the copper plating layer, and is achieved by a multilayer printed circuit board.

According to the present invention, the manufacturing process of the multilayer printed circuit board is simplified and the manufacturing cost is reduced, and the thickness of the copper foil of the outer layer is reduced, so that the micro circuit pattern can be realized and the thickness of the entire substrate can be reduced. It may provide a method.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

1 is a cross-sectional view of a conventional manufacturing process of a multilayer printed circuit board, and FIG. 2 is a cross-sectional view of a manufacturing process of a multilayer printed circuit board of the present invention. 3 is an electron micrograph of a hole formed in the insulating resin of the present invention, Figure 4 is an electron micrograph of a surface treatment process to the insulating resin of the present invention, Figure 5 is a manufacturing process of the multilayer printed circuit board of the present invention Flowchart.

In the present invention, by directly irradiating the CO 2 laser to the insulating resin 17, manufacturing processes such as the conformal exposure, development, corrosion process or UV laser irradiation process can be excluded, and then, copper plating is directly applied to the surface of the insulating resin 17. Therefore, the thickness of the outer layer copper foil can be formed to realize a fine circuit pattern, and the overall thickness of the multilayer circuit board becomes thin.

Referring to FIGS. 2 to 5, the manufacturing process of the printed circuit board of the present invention will be described. First, the insulating resin 17 for interlayer adhesion is adhered to the copper foil 15 having the circuit pattern bonded to the base substrate 10. As the insulating resin 17 for interlayer adhesion used in the embodiment of the present invention, a pre-preg (PREPREG), which is generally used, was used, and thermocompression bonding was performed using a press (not shown) heated on the surface of the copper foil 15. (S1 of FIG. 5).

Thereafter, the hole 20 is processed in the insulating resin 17 to fit the circuit pattern by the CO 2 laser irradiation method (S2 of FIG. 5). 3 shows an insulating resin 17 on which holes 20 are formed.

After that, a desmear process, which is a surface treatment process for increasing the surface roughness of the surface of the insulating resin 17, that is, roughness, is performed (S3 of FIG. 5).

In general, the desmear process dissolves the resin in the inner layer due to frictional heat between the drill bit and the substrate rotated during the hole 20 processing operation, thereby preventing the adhesion of the inner layer attached to the inner wall of the hole 20. It is a process of removing unnecessary resin by chemical methods such as acid salt and dissipate.

In the embodiment of the present invention, the surface treatment process is a desmear step of spraying alkaline chemicals, that is, manganese acid salt, and the desmear process is carried out once on the surface of the insulating resin 17, it is preferable for copper particles to deposit the roughness Configure to level. The electron micrograph of FIG. 4 shows the degree of surface treatment for effectively depositing copper particles.

The desmear process, which is an embodiment of the present invention for increasing the roughness, is an effective method for increasing the deposition effect of copper particles during copper plating, and even if various known surface treatment processes for increasing the roughness of the insulating resin are used. Can be said to be the same. For example, in the case of thermocompression bonding of the conventional copper foil and the insulating resin, the insulating resin is applied even after removing the copper foil by applying pressure to the insulating resin by using the bottom surface (not shown) of the roughly formed copper foil so that the copper foil is easily attached to the insulating resin. During copper plating, sufficient roughness may be formed for the copper particles to be deposited.

Subsequently, copper plating is performed on the insulating resin 17 having the holes 20 to electrically conduct the copper foil 15 (S4 in FIG. 4). In the embodiment of the present invention, electroless copper plating was performed to copper plate the surface of the insulating resin and the hole, and the thickness of the preferred copper plating layer 19 is 10 to 20 µm.

The surface of the insulating resin 17 on which the copper plating layer 19 is formed has the same effect as that of bonding the existing copper foil and at the same time does not undergo a separate process in multiple stages, thereby forming a finer circuit pattern. That is, as shown in Fig. 1, the conventional method comprises a copper plating layer (copper plated) forming the hole 20 in the CO 2 laser irradiation process after the conformal exposure, development, corrosion process or UV laser irradiation process on the upper copper foil (13) ( In order to sufficiently fill the area in which 19 is in contact with the copper foil 15 in the lower portion, the size of the hole 20 is large so as to conduct conduction. As shown in FIG. 2, in the present invention, the insulating resin 17 is directly connected. The hole 20 can be configured by a CO 2 laser irradiation process, and even if the size of the hole 20 is relatively reduced, an area that sufficiently contacts the copper plating layer 19 and the copper foil 15 below can be secured. More holes 20 can be constructed. In addition, by not using the upper copper foil 13, a fine circuit pattern can be realized on the outer layer, and the thickness of the substrate is reduced as a whole.

The copper plating layer 19 is subjected to a general etching process to form a circuit pattern (S5 in Fig. 5).

Subsequently, a multilayer printed circuit board is manufactured by continuously performing thermocompression bonding of insulating resins, hole processing, surface treatment processes, copper plating layers, and circuit patterns in the same manner.

According to the present invention, by reducing the complicated hole configuration process of the multi-layer printed circuit board, the configuration of the microcircuit pattern can be easily and the thickness of the entire substrate can be reduced, thereby reducing costs and increasing productivity.

Although some embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that modifications may be made to the embodiment without departing from the spirit or spirit of the invention. . Therefore, the scope of the invention will be defined by the appended claims and equivalents thereof.

1 is a cross-sectional view of a manufacturing process of a conventional multilayer printed circuit board,

2 is a cross-sectional view of a manufacturing process of a multilayer printed circuit board of the present invention;

3 is an electron micrograph of a hole formed in an insulating resin of the present invention.

4 is an electron micrograph of a surface treatment process performed on an insulating resin of the present invention.

5 is a flowchart illustrating a manufacturing process of a multilayer printed circuit board of the present invention.

* Description of the symbols for the main parts of the drawings *

10: base substrate 13: upper copper foil

15: copper foil 17: insulating resin

19: copper plating layer 20: hall

Claims

In the method of manufacturing a multilayer printed circuit board,

Pressing an insulating resin for interlayer adhesion onto the copper foil;

Irradiating a laser on the surface of the insulating resin to form holes;

Performing a surface treatment process on the surface of the insulating resin in which the holes are formed;

Copper plating the surface of the insulating resin and the hole to form a copper plating layer; And

Forming a circuit pattern on the copper plating layer.

The method of claim 1,

The surface treatment process is a method of manufacturing a multilayer printed circuit board, characterized in that to be performed to increase the roughness by spraying alkaline chemicals.

In a multilayer printed circuit board,

The insulating resin for interlayer adhesion is squeezed onto the copper foil, holes are formed by irradiating laser on the surface of the insulating resin, and the surface of the insulating resin is subjected to a surface treatment process,

Copper plating is performed on the surface of the insulating resin and the hole to form a copper plating layer,

A multi-layer printed circuit board, characterized in that the circuit pattern is formed on the copper plating layer.