Manufacturing method of printed circuit board

Disclosed is a manufacturing method of a printed circuit board. The method in accordance with an embodiment of the present invention includes: providing a laminated substrate having an insulator as well as a first metal layer and a second metal layer, which are sequentially laminated on one side of the insulator; processing a via hole in the laminated substrate; forming a seed layer on an inner wall of the via hole and on a surface of the second metal layer; plating an inside of the via hole and the surface of the second metal layer with a conductive material that is different from a material of the second metal layer; etching the seed layer and the conductive material, formed on the second metal layer; etching the second metal layer; and forming a first circuit pattern by selectively etching the first metal layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2008-0062649, filed with the Korean Intellectual Property Office on Jun. 30, 2008, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a manufacturing method of a printed circuit board.

2. Description of the Related Art

At present, in manufacturing a rigid substrate, a copper clad laminate (CCL) is commonly used as a core material. With a method of laminating layers on the copper clad laminate, a multi-layer substrate is manufactured. Here, the copper clad laminate signifies a material made of an insulator1added by a glass fiber, etc., having copper foils2formed on both sides thereof, as shown inFIG. 1.

Recently, with increasing demands for portable, light and thin electronic devices having many abilities, a thin printed circuit board having high density is also increasingly required.

For that reason, a plating method using a seed layer is widely used as a method of implementing a high density circuit.

FIGS. 1 to 7show a manufacturing method of a printed circuit board according to a related art. Referring toFIGS. 1 to 7, illustrated are an insulator1, a copper foil2, a via hole3, a seed layer4, a plating resist5, a via6and patterns7and8. A manufacturing method of a printed circuit board according to the related art will be concisely described below

First, as shown inFIG. 1, prepared is a copper clad laminate made of an insulator1having copper foils2formed on both sides thereof, and then a via hole3is processed as shown inFIG. 2. A mechanical drill or a laser drill is used as a method of processing the via hole3.

As shown inFIG. 3, a seed layer4is formed on the inner wall of the via hole3and on the surface of the copper foil2, and then a plating resist5is formed as shown inFIG. 4. Subsequently, electrolytic plating is performed as shown inFIG. 5.

A printed circuit board having a predetermined via6and patterns7and8formed therein can be manufactured by removing the plating resist5as shown inFIG. 6and a part of the seed layer4through a flash etching as shown inFIG. 7.

However, according to the related art, when a plating is performed in order to form the via6, and the patterns7and8, the thickness of the plated material is not uniform. Such a thickness difference becomes larger when the lower copper foil2is damaged during the via hole3processing as shown inFIG. 2.

Besides, since there is a case where an excessive etching is processed lest the seed layer4should remain when removing the seed layer4, the pattern may have a possibility of occurrence of more excessive thickness deviation. Due to the reason, it is difficult to form a pattern having a thickness desired by a user.

SUMMARY

The present invention provides a manufacturing method of a high density printed circuit board having reliability.

An aspect of the present invention features a manufacturing method of a printed circuit board. The method in accordance with an embodiment of the present invention can provide: providing a laminated substrate comprising an insulator, a first metal layer and a second metal layer, the first metal layer and the second metal layer configured to be sequentially laminated on one side of the insulator; processing a via hole in the laminated substrate; forming a seed layer on an inner wall of the via hole and on a surface of the second metal layer; plating an inside of the via hole and the surface of the second metal layer with a conductive material, the conductive material being different from a material of the second metal layer; etching the seed layer and the conductive material formed on the second metal layer; etching the second metal layer; and forming a first circuit pattern by selectively etching the first metal layer.

Another aspect of the present invention features a manufacturing method of a printed circuit board. The method in accordance with an embodiment of the present invention can provide: providing a laminated substrate comprising an insulator, a first metal layer and a second metal layer, the first metal layer and the second metal layer configured to be sequentially laminated on one side of the insulator; processing a via hole in the laminated substrate; etching the second metal layer; forming a seed layer on an inner wall of the via hole and on a surface of the first metal layer; forming a patterned plating resist on the first metal layer; plating the seed layer and an inside of the via hole with a conductive material; removing the plating resist; and etching a part of the seed layer and a part of the first metal layer.

Yet another aspect of the present invention features a manufacturing method of a printed circuit board. The method in accordance with an embodiment of the present invention can provide: providing a laminated substrate comprising an insulator, a first metal layer and a second metal layer, the first metal layer and the second metal layer configured to be sequentially laminated on one side of the insulator; processing a via hole in the laminated substrate; forming a seed layer on an inner wall of the via hole and on a surface of the second metal layer; forming a patterned plating resist on the second metal layer; plating the seed layer and an inside of the via hole with a conductive material; removing the plating resist; etching a part of the seed layer; etching a part of the second metal layer; and etching a part of the first metal layer.

The manufacturing methods of the printed circuit board in accordance with various aspects of the present invention can feature as follows:

For example, the first metal layer and the conductive material can be made of a material comprising copper (Cu), and the second metal layer is made of a material comprising at least one of nickel (Ni), aluminum (Al) and chrome (Cr).

Meanwhile, the laminated substrate can be manufactured by plating the first metal layer laminated on the insulator with a material corresponding to the second metal layer. A circuit substrate having a second circuit pattern formed on the surface thereof can be laminated on another side of the insulator.

Additionally, the plating can be performed to allow the conductive material to be filled inside the via hole.

DETAILED DESCRIPTION

Since there can be a variety of permutations and embodiments of the present invention, certain embodiments will be illustrated and described with reference to the accompanying drawings.

Terms such as “first” and “second” can be used in describing various elements, but the above elements shall not be restricted to the above terms. The above terms are used only to distinguish one element from the other.

The terms used in the description are intended to describe certain embodiments only, and shall by no means restrict the present invention. Unless clearly used otherwise, expressions in the singular number include a plural meaning. In the present description, an expression such as “comprising” or “consisting of” is intended to designate a characteristic, a number, a step, an operation, an element, a part or combinations thereof, and shall not be construed to preclude any presence or possibility of one or more other characteristics, numbers, steps, operations, elements, parts or combinations thereof.

Hereinafter, embodiments of a manufacturing method of a printed circuit board in accordance with the present invention will be described in detail with reference to the accompanying drawings. In description with reference to accompanying drawings, the same reference numerals will be assigned to the same or corresponding elements, and repetitive descriptions thereof will be omitted.

FIG. 8shows a flowchart of a manufacturing method of a printed circuit board according to a first embodiment of the present invention.FIGS. 9 to 21show a manufacturing method of a printed circuit board according to a first embodiment of the present invention. Referring toFIGS. 9 to 21, illustrated are an insulator11, a first metal layer12, patterns12aand12b, a second metal layer13, a via hole15a, a via15, a seed layer16, a plating layer17, an etching resist18, a circuit substrate20, patterns21and23, and a via22.

First, as shown inFIG. 10, provided is a laminated substrate including an insulator11, and including a first metal layer12and a second metal layer13sequentially laminated on the insulator11(S110). That is, a laminated substrate having a dualized metal layer is prepared. For this, as shown inFIG. 9, it is possible to use a method of forming the second metal layer13by performing electrolytic plating onto a material having the insulator11that has the first metal layer12adhered thereto. In addition, it shall be evident that a method of adhering a film-type second metal layer to the first metal layer can be used.

Meanwhile, the material of the first metal layer12is different from that of the second metal layer13. For example, the first metal layer12can be mainly made of copper. The second metal layer13can be mainly made of at least of nickel (Ni), aluminum (Al) and chrome (Cr) (e.g., sulfonic acid nickel).

A via hole15ais processed in the laminated substrate having such a dualized metal layer as shown inFIG. 11(S120). In order to process the via hole15a, a laser drill like a CO2laser can be used. In some cases, a mechanical drill can be also used.

Subsequently, as shown inFIG. 12, a seed layer16is formed on the inner wall of the via hole15aand on the surface of the second metal layer13(S130). As shown inFIG. 13, a conductive material different from that of the second metal layer13is plated both onto the inside of the via hole15aand onto the second metal layer13(S140).

In order to form the seed layer16, an electroless plating like a chemical copper plating can be used. As described above, when the second metal layer13is made of sulfonic acid nickel, the seed layer16and the conductive material can be made of copper just as the first metal layer12is made of copper.

Next, the seed layer16and the conductive material, i.e., a plating layer17, formed on the second metal layer13, are etched as shown inFIG. 14(S150). When the copper-made plating layer17and the seed layer16are etched in a state where the nickel-made second metal layer13is disposed beneath the seed layer and the plating layer, the corresponding etching solution does not affect the second metal layer13made of materials such as nickel (Ni), aluminum (Al) or chrome (Cr) so that the second metal layer13can perform a function as an etch-stop.

As a result, since the first metal layer12located beneath the second metal layer13is not affected by the etching solution, it is possible to construct a structure in which a via15is formed prior to a pattern to be formed, as shown inFIG. 14.

As shown inFIG. 15, the second metal layer13is etched (S160). Because the first metal layer12is made of a material different from that of the second metal layer13, the first metal layer12cannot be affected by the corresponding etching solution during the process of removing the second metal layer13by applying the etching solution.

Subsequently, as shown inFIG. 16, first patterns12aand12bcan be formed by forming an etching resist18patterned on the first metal layer12and by selectively etching the first metal layer12(S170).

As described above, in the embodiment of the present invention, the via15is first formed by using plating process, and then the patterns12aand12bare formed by etching process, so that it is possible to manufacture a high density printed circuit board20having a pattern with a uniform thickness.

While a method manufacturing of the two-layer printed circuit board20is proposed inFIGS. 9 to 17, it is also possible to manufacture a multi-layer printed circuit board as shown inFIGS. 18 to 21.

In other words, as shown inFIG. 19, a printed circuit board can be also manufactured by making use of a structure in which a circuit substrate20having a predetermined via22and patterns21and23formed therein is laminated on the lower side of the insulator11, and in which the first metal layer12and the second metal layer13are sequentially laminated on the upper side of the insulator11as described above.

In order to construct such a structure, as shown inFIG. 18, it is possible to use a method of forming the second metal layer13by sequentially and collectively laminating the insulator11and the first metal layer12on the upper side of the circuit substrate20, and then by performing the electrolytic plating onto the first metal layer12. In addition, it shall be evident that a method of adhering a film-type second metal layer to the first metal layer can be used.

Subsequent process is the same as the process described above. That is, after the via hole15ais processed as shown inFIG. 20, the processes S130to S170described above are performed. Consequently, a printed circuit board having the structure as shown inFIG. 21can be manufactured.

In the next place, a manufacturing method of a printed circuit board according to a second embodiment of the present invention will be described.

FIG. 22shows a flowchart of a manufacturing method of a printed circuit board according to a second embodiment of the present invention.FIGS. 23 to 29show a manufacturing method of a printed circuit board according to a second embodiment of the present invention. Referring toFIGS. 23 to 29, illustrated are an insulator31, a first metal layer32, a second metal layer33, a via35, a via hole35a, a seed layer36, a plating resist37, a pattern38and a pad39.

First, as shown inFIG. 23, prepares is a laminated substrate including an insulator31, and including a first metal layer32and a second metal layer33sequentially laminated on the insulator31(S210). A via hole35ais processed by using CO2laser (S220). According to the embodiment of the present invention, since the second metal layer33is formed beneath the first metal layer32which is under the insulator such that the first metal layer32can be supported, it is possible to minimize the damage of the first metal layer32which is under the insulator during the process of the via hole35aby using the CO2laser.

As shown inFIG. 24, the second metal layer33is removed (S230). The second metal layer33can be removed by using chemical etching. As described above, because the second metal layer33is made of a material different from that of the first metal layer32, the first metal layer32cannot be damaged during the process of removing the second metal layer33by using an etching solution for removing the second metal layer33.

Subsequently, as shown inFIG. 25, a seed layer36is formed both on the surface of the first metal layer32and on the inner wall of the via hole35a(S240). As shown inFIG. 26, formed is a plating resist37patterned so as to correspond to a pattern designed to be formed (S250), and then a conductive material is plated onto the inside of the via hole and onto the seed layer as shown inFIG. 27. As a result, a pad39and a pattern38, for example, a via land are formed (S260).

Subsequently, the plating resist37is removed as shown inFIG. 28(S270) and a part of the seed layer36and a part of the first metal layer32are removed through the flash etching as shown inFIG. 29(S280), so that a printed circuit board having a via on pad (VOP) structure directly connecting the pad39with the via35can be completed.

Next, a manufacturing method of a printed circuit board according to a third embodiment of the present invention will be described.FIG. 30shows a flowchart of a manufacturing method of a printed circuit board according to a third embodiment of the present invention.FIGS. 31 to 38show a manufacturing method of a printed circuit board according to a third embodiment of the present invention. Referring toFIGS. 31 to 38, illustrated are an insulator31, a first metal layer32, a second metal layer33, a via35, a via hole35a, a seed layer36, a plating resist37, a pattern38and a pad39.

While a method of forming a seed layer36by processing a via hole35athrough use of a CO2laser and by removing a second metal layer33is proposed in the second embodiment previously described, a method of forming the seed layer36without removing the second metal layer33is proposed in this embodiment.

That is, as shown inFIG. 31, a via hole35is processed in the laminated substrate including an insulator31, and including a first metal layer32and a second metal layer33sequentially laminated on the insulator31(S310and S320). As shown inFIG. 32, a seed layer36can be formed both on the surface of the second metal layer33and on the inner wall of the via hole35a(S330).

As shown inFIG. 33, a plating resist37is formed onto the second metal layer33(S340). As shown inFIG. 34, a conductive material is plated both onto the inside of the via hole and onto the seed layer (S350). As shown inFIG. 35, the plating resist37is removed (S360).

In this case, since the second metal layer33remains, a printed circuit board having a via on pad (VOP) structure can be manufactured by a method of removing the seed layer36through a flash etching as shown inFIG. 36(S370), and then by removing a part of the second metal layer33as shown inFIG. 37(S380) and by removing a part of the metal layer32as shown inFIG. 38(S390).

While certain embodiment of the present invention has been described, it shall be understood by those skilled in the art that various changes and modification in forms and details may be made without departing from the spirit and scope of the present invention as defined by the appended claims.

Numerous embodiments other than embodiments described above are included within the scope of the present invention.