KR20070079794A - Manufacturing method of printed circuit board - Google Patents

Abstract

A method for manufacturing a printed circuit board is provided to reduce the manufacturing cost and process by using only an electric copper plating process. In a method for manufacturing a printed circuit board, a circular plate including an insulation layer(111) and a first copper foil and a second copper foil on both planes of the insulation layer is prepared. A blind via hole is formed for electrical conduction of the circular plate. A plated resist(115) is deposited on the bottom of the second copper foil located on the bottom of the insulation layer. A copper plated layer(116) is formed in the blind via hole by applying a current to the second copper foil.

Description

Manufacturing Method of Printed Circuit Board

1A to 1E are cross-sectional views illustrating a conventional method for manufacturing a printed circuit board.

2A to 2C are cross-sectional views showing a method for manufacturing a via hole according to the prior art.

3A to 3G are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

10, 100: 11, 111: insulating layer

12, 112a, 112b: copper foil 13, 113: blind via hole

14, 1114: solder resist pattern 15, 117: plating layer

115: plating resistor 116: copper plating layer

The present invention relates to a printed circuit board and a method of manufacturing the same. More particularly, the present invention relates to a printed circuit board which can improve the heat dissipation characteristics by improving the copper plating layer filling rate in the via hole, as well as reducing the copper plating process time and manufacturing cost. It relates to a manufacturing method.

Printed Circuit Board (PCB) is a printed wiring board that forms conductors on insulating boards based on circuit design. The electrical wiring between electronic components is called a PCB board, printed circuit board, or printed wiring board. .

In general, a printed circuit board is formed by attaching a copper thin plate to a surface of a phenol resin insulator or an epoxy resin insulator, and then etching it according to the wiring pattern of the circuit to form a necessary circuit, and various electrical and electronic devices such as IC, capacitor, and resistor thereon. It is an insulating flat plate that allows compact mounting of parts.

That is, a circuit for connecting the electronic components with each other is formed in the shape of a wiring on the surface of the insulating plate. Printed circuit boards are classified into single-sided boards, double-sided boards, and multilayer boards according to the number of printed circuit boards. The higher the number of layers, the better the mounting force of the parts and the high-precision products.

The method of manufacturing a printed circuit board is divided into a drill process for processing holes, a copper plating process for imparting conductivity of the processed holes, and a circuit process for forming a circuit.

1A to 1E are cross-sectional views illustrating a method of manufacturing a conventional printed circuit board.

In the conventional method of manufacturing a printed circuit board, first, as shown in FIG. 1A, an original plate 10, which is a copper foil laminated plate including a copper foil 12 on both surfaces of an insulating layer 11 and an insulating layer 11, is prepared.

Thereafter, as shown in FIG. 1B, a blind via hole (hereinafter referred to as “BVH”) 13 for electrical conduction of the original plate 10 is formed by using a laser.

Subsequently, a copper plating layer is formed on the inner wall of the BVH 13 so as to electrically conduct the original plate 10 as shown in FIG. 1C through chemical copper plating, that is, an electroless copper plating process and an electrolytic copper plating process, and also the circuit patterns 12a and 12b. ).

After the circuit patterns 12a and 12b are formed, a solder resist is applied onto the circuit patterns 12a and 12b and then exposed, developed, and dried to externally supply power and exchange signals. The solder resist pattern 14 is formed in the remaining region except for the portion connected to the terminal as illustrated in FIG. 1D.

Subsequently, a portion of the wire bonding pad and the solder ball pad connected to the external terminal, that is, a plating layer made of metal having high hardness and good conductivity, such as gold, nickel, and rhodium, as shown in FIG. 1E. (15) is formed.

2A to 2C are diagrams illustrating a method of manufacturing a via hole according to the related art.

As shown in FIG. 2A, when the BVH 13 is formed by a laser, various debris and foreign substances generated during the BVH 13 processing are removed by a deburring and desmear process.

Thereafter, as shown in FIG. 2B, the electroless copper plating layer 20 is formed on the inner wall of the BVH 13 by about 0.2 μm to 0.4 μm in order to impart conductivity in the BVH 13.

After the electroless copper plating layer 20 is formed, a current is applied to the copper foil 12 positioned above and below the insulating layer 11 to form a uniform electroplating layer 22 as shown in FIG. 2C.

However, the conventional method of manufacturing a printed circuit board using the electroless copper plating process has a problem in that the cost is increased because it is difficult to manage the plating solution during electroless copper plating and the cost of the entire copper plating process is the largest.

In addition, the electroless copper plating process requires a lot of processing time, and when the electroplating layer 22 having a desired thickness is formed, the electroplating layer 22 does not completely fill the inside of the BVH 13 hole. There is a problem that the heat release characteristic of 12) is lowered.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a printed circuit board which can reduce the manufacturing cost and shorten the manufacturing process using only the electroplating process.

In addition, an object of the present invention is to provide a method for manufacturing a printed circuit board which can improve heat dissipation characteristics of copper foil by improving the filling rate using only electrolytic copper plating.

In order to achieve the above object, the present invention comprises the steps of preparing a disc including an insulating layer and a first copper foil and a second copper foil on both sides of the insulating layer; Forming a blind via hole for electrical conduction of the disc; Depositing a plating resistor under the second copper foil under the insulating layer; And forming a copper plating layer in the blind via hole by applying a current to the second copper foil.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A to 3G are cross-sectional views illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

First, as illustrated in FIG. 3A, an original plate 100, which is a copper clad laminate including copper foils 112a and 112b on both surfaces of the insulating layer 111 and the insulating layer 111, is prepared. At this time, the thickness of the copper foils 112a and 112b has a thickness enough to form a circuit pattern.

When the disc 100 is prepared, a blind via hole 113 (BVH) 113 is formed using a laser as shown in FIG. 3B. When the BVH 113 is formed, various debris and foreign substances generated during the BVH 113 processing are removed by a deburring and desmear process.

Thereafter, as illustrated in FIG. 3C, the plating resistor 115 is stacked below the second copper foil 112b to control the plating thickness of the second copper foil 112b stacked below the insulating layer 111. At this time, a dry film is used as the plating resistor 115.

After laminating the plating resistor 115, the copper plating layer 116 is formed by an electrolytic copper plating process as shown in FIG. 3D. At this time, the current is applied only to the second copper foil 112b laminated under the insulating layer 111. In addition, the copper plating layer 116 is completely filled in the BVH 113. Thereby, the heat dissipation characteristic of the copper foil 112a, 112b improves.

After the copper plating layer 116 is formed, a dry film is deposited on the copper plating layer 116, and the artwork film, that is, a mask is adhered to the dry film, and then exposed to ultraviolet rays (UV). Thereafter, as illustrated in FIG. 3E, the circuit patterns 112a and 112b are formed through the development and etching process, and the dry films deposited on the circuit patterns 112a and 112b are removed.

After the circuit patterns 112a and 112b are formed, a solder resist is applied onto the circuit patterns 112a and 112b, and then exposed, developed, and dried to externally supply power and exchange signals. A solder resist pattern 114 is formed in the remaining region except for the portion connected to the terminal as shown in FIG. 3F.

Subsequently, the portion connected to the external terminal, that is, the wire bonding pad and the solder ball pad, as shown in FIG. 3g, is a plated layer made of metal having high hardness and good conductivity such as gold, nickel, rhodium, and the like. 117 is formed.

As described above, the present invention can reduce the manufacturing process time and manufacturing cost of the printed circuit board by eliminating the electroless copper plating process, and also reduce the defects generated during electroless copper plating.

In addition, the present invention can control the plating layer thickness of the copper foil located under the insulating layer by laminating a plating resist on the lower copper foil located under the insulating layer during electrolytic copper plating.

In addition, the present invention may improve the filling rate of the copper plating layer formed inside the via hole because the copper plating layer is formed inside the via hole by applying current only to the lower copper foil during electrolytic copper plating. Thereby, this invention can improve the heat emission characteristic of copper foil.

Claims (3)

Preparing a disc including an insulating layer and a first copper foil and a second copper foil on both sides of the insulating layer; Forming a blind via hole for electrical conduction of the disc; Depositing a plating resistor under the second copper foil under the insulating layer; And And applying a current to the second copper foil to form a copper plating layer inside the blind via hole. The method of claim 1, The plating resistor is a dry film manufacturing method, characterized in that the dry film. The method of claim 1, The copper plating layer is a manufacturing method of a printed circuit board, characterized in that completely filled in the blind via hole.

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