KR101044152B1 - A printed circuit board and a fabricating method the same - Google Patents

Abstract

The present invention relates to a printed circuit board and a method of manufacturing the same, wherein an insulator layer has a via hole having a width smaller than an inner width thereof, and an inner wall of the via hole. It characterized in that it comprises a plating layer to form a void in the interior, to minimize the thickness of the plating layer provides a printed circuit board and a method of manufacturing the same that can implement a fine circuit.

Insulation Layer, Width, Via Hole, Void, Inlet, Thickness, Microcircuit

Description

A printed circuit board and a fabrication method the same

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

As high functional and light and thin electronic components, printed circuit boards equipped with such electronic components are also required to be densified, and one of the technologies to cope with these demands is the active research on the interlayer electrical conduction technology of circuit patterns. have.

An interlayer connection method using vias is generally used as an interlayer electrical conduction technology for circuit patterns. Recently, as the solder ball pitch is miniaturized, the via structure is shifted from a staggered via structure to a stack via structure using a filled via technique.

1 through 4 are cross-sectional views illustrating a method of manufacturing a printed circuit board having field vias according to the prior art, in the order of a process. Hereinafter, a method of manufacturing a printed circuit board having a field via according to the prior art will be described with reference to the following.

First, as shown in FIG. 1, through holes having a constant width are formed in a copper clad laminate (CCL) in which copper foil layers 12 are laminated on both surfaces of insulating layer 10 by using a drill bit or the like. ; 14).

Next, as shown in FIG. 2, the plating layer 16 is formed until the entire inside of the through hole 14 is plated by performing an electroless plating process and an electrolytic plating process. In this case, when the thickness of the plating layer 16 is small, the surface of the plating layer 16 is not flat due to the difference in the plating speed between the surface of the copper foil layer 12 and the through hole 14. Will occur.

Next, as shown in FIG. 3, an additional plating process is performed to remove the dimples 18 to form the plating layer 16 ′.

Finally, as shown in FIG. 4, a thickly formed plating layer 16 ′ is removed by etching to form a plating layer 16 ″ to form a printed circuit board.

However, according to the prior art, since the through hole 14 has a structure having a constant width, in order to remove the dimple portion 18 while plating the entire inside of the through hole 14, the thickness of the plating layer 16 'is increased. There was a difficulty in realizing a microcircuit because it must be large. In addition, in order to solve this problem, there was a problem that an etching process must be additionally performed.

The present invention has been made to solve the above problems, an object of the present invention is to provide a printed circuit board and a method of manufacturing the same that can implement a fine circuit by minimizing the thickness of the plating layer.

A printed circuit board according to a preferred embodiment of the present invention includes an insulating layer including a via hole having a width smaller than an inner portion of an inlet portion, and an inner wall of the via hole, and formed in the insulating layer to block the inlet portion of the via hole. It characterized in that it comprises a plating layer to form a void therein.

Here, the via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion.

In addition, the via hole is characterized in that the width gradually increases from the inlet toward the inside.

The insulating layer may include at least one glass fiber layer formed to protrude into the via hole therein, and the first plating layer formed at one side of the via hole and the via hole in the glass fiber layer formed to protrude into the via hole. The second plating layers formed on the other side are connected to each other to form the voids above and below, respectively.

In addition, the insulating layer includes at least one glass fiber layer formed to protrude into the via hole therein, wherein the first glass fiber layer formed to protrude from one side of the via hole is a second glass fiber layer formed to protrude from the other side of the via hole. It is characterized in that separated from.

In addition, a copper foil layer is laminated on the insulating layer, and the plating layer is formed on the copper foil layer including an inner wall of the via hole.

In addition, the width of the inlet portion formed by removing the copper foil layer may be smaller than the width of the inner portion formed by removing the insulating layer.

According to a preferred embodiment of the present invention, there is provided a method of manufacturing a printed circuit board, including: (A) processing a via hole having a width of an inlet portion smaller than an inner width thereof in an insulating layer, and (B) including an inner wall of the via hole. Performing a plating process on the layer, thereby forming a plating layer which forms a void in the via hole by blocking the inlet.

In this case, in the step (A), the via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion.

In addition, in the step (A), the via hole is characterized in that the width gradually increases from the inlet toward the inside.

In addition, in the step (A), the insulating layer includes at least one glass fiber layer impregnated therein, wherein the glass fiber layer is formed to protrude into the via hole.

In addition, the first glass fiber layer formed to protrude from one side of the via hole is characterized in that separated from the second glass fiber layer formed to protrude from the other side of the via hole.

Further, in the step (B), in the glass fiber layer formed to protrude into the via hole, the first plating layer formed on one side of the via hole and the second plating layer formed on the other side of the via hole are connected to each other and the upper and lower voids respectively. Characterized in that form.

According to another aspect of the present invention, there is provided a method of manufacturing a printed circuit board, the method including: (A) processing a via hole having a width smaller than an inner width of a copper foil laminated plate having a copper foil layer laminated on an insulating layer, and (B) And performing a plating process on the copper foil layer including an inner wall of the via hole to block the inlet to form a plating layer to form voids in the via hole.

In this case, in the step (A), the via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion.

In addition, in the step (A), the via hole is characterized in that the width gradually increases from the inlet toward the inside.

In addition, in the step (A), the width of the inlet portion formed by removing the copper foil layer is smaller than the inner width formed by removing the insulating layer.

In addition, in the step (A), the insulating layer includes at least one glass fiber layer impregnated therein, wherein the glass fiber layer is formed to protrude into the via hole.

In addition, the first glass fiber layer formed to protrude from one side of the via hole is characterized in that separated from the second glass fiber layer formed to protrude from the other side of the via hole.

Further, in the step (B), in the glass fiber layer formed to protrude into the via hole, the first plating layer formed on one side of the via hole and the second plating layer formed on the other side of the via hole are connected to each other to form the voids above and below, respectively. It is characterized by forming.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

Prior to this, terms and words used in the present specification and claims should not be construed in a conventional and dictionary sense, and the inventor may appropriately define the concept of a term in order to best describe its invention The present invention should be construed in accordance with the spirit and scope of the present invention.

According to the present invention, since the plating layer is formed in the via hole which becomes smaller in width, the plating layer is formed while the inlet portion of the via hole is blocked, so that the plating layer is formed flat at a thin plating thickness, and thus the dimple phenomenon is eliminated and the microcircuit is removed. Can be implemented.

The objects, specific advantages and novel features of the present invention will become more apparent from the following detailed description and the preferred embodiments associated with the accompanying drawings. In the present specification, in adding reference numerals to the components of each drawing, it should be noted that the same components as possible, even if displayed on different drawings have the same number as possible. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

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

Structure of a Printed Circuit Board-Part 1 Example

5 is a cross-sectional view of a printed circuit board according to a first exemplary embodiment of the present invention. Hereinafter, the printed circuit board 100a according to the present exemplary embodiment will be described with reference to the drawings.

As shown in FIG. 5, in the printed circuit board 100a according to the present exemplary embodiment, a via hole 112 having a width Wa of an inlet portion smaller than an inner width Wb is formed in the insulating layer 110, and a via hole is formed in the insulating layer 110. The plating layer 120 ′ is formed on the insulating layer 110 including the inner wall of 112, but the width Wa of the inlet portion is smaller than the width Wb of the inner portion, so that the plating layer 120 ′ blocks the inlet portion. It is characterized by having a structure in which the void 122 is formed inside the hole 112.

That is, in this embodiment, since the plating layer 120 'is formed in the via hole 112 having a narrower width than the inside of the inlet, the plating layer 120' blocks the inlet before the entire inside of the via hole 112 is plated. 112 has a void 122 therein, and since the plating layer 120 'is continuously formed while the inlet is blocked, the plating layer 120' has a thinner thickness than the conventional via hole structure having a constant width. ) Is flattened to prevent dimples and to implement microcircuits.

Here, the via hole 112 has a maximum width at the center portion so as to have a vertically symmetrical structure, and preferably has a symmetrical structure with respect to the center portion.

In addition, the via hole 112 may have, for example, a tapered or curved shape so as to gradually increase in width from the inlet to the inside.

Meanwhile, according to the present exemplary embodiment, although the entire inside of the via hole 112 does not have a filled via structure, the plating layer 120 may be continuously formed while the inlet of the via hole 112 is blocked. Therefore, the upper portion of the via hole 112 may perform a function of a pad portion in which solder balls may be formed, thereby enabling fine pitching of the solder balls.

Structure of a Printed Circuit Board-Second Example

6A and 6B are cross-sectional views of a printed circuit board according to a second preferred embodiment of the present invention. Hereinafter, the printed circuit board 100b according to the present exemplary embodiment will be described with reference to the drawings.

As shown in FIG. 6A, the printed circuit board 100b according to the present exemplary embodiment is formed such that one or more glass fiber layers 114 included in the insulating layer 110 protrude into the via hole 112. The first plating layer 120a formed on one side of the via hole 112 and the second plating layer 120b formed on the other side of the via hole 112 are connected to each other in the glass fiber layers 114a and 114b formed to protrude into the via hole 112. This has a structure in which the voids 122a and 122b are formed above and below each other.

In this case, since the first plating layer 120a and the second plating layer 120b are connected to the glass fiber layers 114a and 114b formed to protrude into the via hole 112, the inside of the via hole 112 may be connected. Compared to the first embodiment having the entire void 122, the area occupied by the voids 122a and 122b is reduced, and the strength / reliability of the printed circuit board can be improved. In addition, since the connection portion between the first plating layer 120a and the second plating layer 120b in the via hole 112 generates the effect of dividing the via hole 112 to reduce the thickness of the via hole 112, the via hole 112. Internal plating process control becomes easier.

Here, the glass fiber layer 114 is a reinforcing material for maintaining electrical insulation, mechanical strength and rigidity, and dimensional stability, which are basic characteristics of a printed circuit board, by weaving a fiber bundle composed of short fibers having a diameter of 5 to 9 μm. Is made. The glass fiber layer 114 includes a first glass fiber layer 114a formed to protrude on one side of the via hole 112 and a second glass fiber layer 114b protruded to the other side of the via hole 112, but the first glass fiber layer It is preferable that the 114a and the second glass fiber layers 114b have a separate structure. This is to prevent the phenomenon in which the upper and lower plating layers 120 'are blocked based on the first glass fiber layer 114a and the second glass fiber layer 114b connected thereto.

Meanwhile, in FIG. 6B, the plating layer 120 ′ is formed in a state in which two glass fiber layers 114 and 114 ′ are included in the insulating layer 110, and three voids 122a, 122b, and 122c are formed in the via hole 112. Is shown.

Structure of a Printed Circuit Board-Third Example

7A to 7D are cross-sectional views of a printed circuit board according to a third exemplary embodiment of the present invention. Hereinafter, the printed circuit board 100c according to the present exemplary embodiment will be described with reference to the drawings.

As shown in FIG. 7A, in the printed circuit board 100c according to the present exemplary embodiment, the width Wa of the inlet part is the width Wb of the inside of the printed circuit board 100c in a state where the copper foil layer 116 is stacked on the insulating layer 110. A smaller via hole 112 is formed, and a plating layer 120 ′ is formed in the copper foil layer 116 including the inner wall of the via hole 112, and the plating layer 120 ′ blocks the inlet part to form the inside of the via hole 112. It is characterized in that the void 122 is formed.

As described above, when the copper foil layer 116 is stacked on the insulating layer 110, the width Wa of the inlet portion can be controlled by processing the copper foil layer 116, and the width Wb of the inside is the insulating layer 110. It becomes controllable by processing. Here, the insulating layer 110 may have an inner width Wb larger than the width Wa of the inlet portion formed by the copper foil layer 116, but may have a constant inner width Wb.

On the other hand, the printed circuit board 100c according to the present embodiment has a structure in which the via hole 112 gradually increases from the inlet part toward the inside (see FIG. 7B) and the glass fiber layer 114 impregnated in the insulating layer 110. It may have a structure (see FIGS. 7C and 7D) protruding into the via hole 112.

Manufacturing Method of Printed Circuit Board-Part 1 Example

8 to 10 are process cross-sectional views showing the manufacturing method of the printed circuit board according to the first preferred embodiment of the present invention in the process order. Hereinafter, a manufacturing method of the printed circuit board 100a according to the present embodiment will be described with reference to this.

First, as shown in FIG. 8, the via hole 112 having the width Wa of the inlet portion smaller than the width Wb in the insulating layer 110 is processed.

At this time, the via hole 112 is processed, for example, by adjusting the irradiation intensity and / or frequency range of the laser.

Here, the via hole 112 is tapered or curved in shape so as to gradually increase inward from the inlet part, or is processed in a vertically symmetrical structure with respect to the central part having the maximum width.

Next, as shown in FIG. 9, the plating layer 120 is formed by performing an electroless / electrolytic plating process on the insulating layer 110 including the inner wall of the via hole 112.

At this time, since the via hole 112 has a narrower structure than the inside thereof, the plating layer 120 forms an inlet portion of the via hole 112 in the process of plating the inner wall of the via hole 112 and the insulating layer 110. The void 122 is formed in the via hole 112.

Here, the dimple portion 124 is formed on the upper portion of the inlet of the via hole 112 by the plating speed difference with respect to the inner wall of the insulating layer 110 and the via hole 112. However, in the present embodiment, rather than plating the entire via hole 112, the plating process is performed until the inlet portion of the via hole 112 is blocked, thereby reducing the thickness of the dimple portion 124 compared to the conventional structure.

Finally, as shown in FIG. 10, an additional plating process is performed to remove the dimples 124 to form a plating layer 120 ′ having a flat structure. Since the thickness of the dimple portion 124 is smaller than that of the conventional structure, the thickness of the plating layer 120 ′ is reduced compared to that of the conventional structure, thereby enabling the implementation of a fine circuit.

By this process, the printed circuit board 100a as shown in FIG. 5 is manufactured. Meanwhile, if necessary, the plating layer 120 ′ may be etched / polished to have an appropriate thickness, and a patterning process for forming a circuit layer may be performed.

Manufacturing Method of Printed Circuit Board-Second Example

11 to 13 are process cross-sectional views illustrating a method of manufacturing a printed circuit board according to a second preferred embodiment of the present invention in the order of process. Hereinafter, a method of manufacturing the printed circuit board 100b according to the present exemplary embodiment will be described with reference to this.

First, as shown in FIG. 11, in the insulating layer 110 impregnated with one or more glass fiber layers 114, the glass fiber layer 114 protrudes therein, but the width Wa of the inlet portion is the width Wb of the inside. The smaller via hole 112 is machined.

At this time, the glass fiber layer 114a protruding from one side of the insulating layer 110 and the glass fiber layer 114b protruding from the other side of the insulating layer 110 are processed to be separated from each other.

Next, as shown in FIG. 12, the plating layer 120 is formed by performing an electroless / electrolytic plating process on the insulating layer 110 including the inner wall of the via hole 112.

At this time, since the glass fiber layers 114a and 114b protrude into the via hole 112, the first plating layer 120a formed on one side of the via hole 112 and the second formed on the other side of the via hole 112 in this region. The plating layers 120b are connected to each other, and the voids 122a and 122b are formed at the upper and lower portions, respectively.

Finally, as shown in FIG. 13, an additional plating process is performed to remove the dimples 124 to form a plating layer 120 ′ having a flat structure.

By such a process, the printed circuit board 100b as shown in FIG. 6 is manufactured.

Manufacturing Method of Printed Circuit Board-Part 3 Example

14 to 16 are process cross-sectional views showing a method of manufacturing a printed circuit board according to a third preferred embodiment of the present invention in the order of process. Hereinafter, a method of manufacturing the printed circuit board 100c according to the present embodiment will be described with reference to this.

As shown in FIG. 14, in the state in which the copper foil layer 116 is stacked on the insulating layer 110, the via hole 112 having a width Wa of the inlet portion is smaller than the width Wb therein.

In this case, when the copper foil layer 116 is laminated on the insulating layer 110, the width Wa of the inlet portion can be controlled by processing the copper foil layer 116, and the width Wb of the inner portion of the copper foil layer 116 is defined as the insulating layer 110. By processing, it becomes controllable. Here, the insulating layer 110 may have an inner width Wb larger than the width Wa of the inlet portion formed by the copper foil layer 116, but may have a constant inner width Wb.

Next, as shown in FIG. 15, the plating layer 120 is formed by performing an electroless / electrolytic plating process on the copper foil layer 116 including the inner wall of the via hole 112.

In this case, since the via hole 112 has a structure in which the inlet portion is narrower than the inside, the plating layer 120 blocks the inlet portion of the via hole 112 in the process of plating the inner wall of the via hole 112 and the insulating layer 110. The void 122 is formed in the via hole 112. Here, the void 122 may have various shapes according to the shape of the via hole 112.

Finally, as shown in FIG. 16, an additional plating process is performed to remove the dimples 124 to form a plating layer 120 ′ having a flat structure.

By this process, the printed circuit board 100c as shown in FIG. 7 is manufactured.

Although the present invention has been described in detail through specific embodiments, this is for explaining the present invention in detail, and the printed circuit board and the manufacturing method thereof according to the present invention are not limited thereto, and the technical field of the present invention is related to the present invention. It will be apparent that modifications and improvements are possible by those skilled in the art.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

1 to 4 are process cross-sectional views showing a manufacturing method of a printed circuit board having a field via according to the prior art in the order of process.

5 is a cross-sectional view of a printed circuit board according to a first exemplary embodiment of the present invention.

6A and 6B are cross-sectional views of a printed circuit board according to a second preferred embodiment of the present invention.

7A to 7D are cross-sectional views of a printed circuit board according to a third exemplary embodiment of the present invention.

8 to 10 are process cross-sectional views showing the manufacturing method of the printed circuit board according to the first preferred embodiment of the present invention in the process order.

11 to 13 are process cross-sectional views illustrating a method of manufacturing a printed circuit board according to a second preferred embodiment of the present invention in the order of process.

14 to 16 are process cross-sectional views showing a method of manufacturing a printed circuit board according to a third preferred embodiment of the present invention in the order of process.

<Description of the symbols for the main parts of the drawings>

110: insulating layer 112: via hole

114, 114 ', 114a, 114b: glass fiber layer 116: copper foil layer

120, 120 ': plating layer

122, 122a, 122b, 122c: void

124: dimple

Claims (20)

An insulating layer having a via hole having a width smaller than an inner width of the inlet portion; And A plating layer formed on the insulating layer including an inner wall of the via hole and blocking the inlet to form a void in the via hole; Printed circuit board comprising a. The method according to claim 1, The via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion. The method according to claim 1, The via hole is a printed circuit board, characterized in that the width gradually increases from the inlet toward the inside. The method according to claim 1, The insulating layer may include at least one glass fiber layer formed to protrude into the via hole therein, and the first plating layer formed at one side of the via hole and the other side of the via hole in the glass fiber layer formed to protrude into the via hole. The formed second plating layer is connected to each other to form the voids up and down respectively. The method according to claim 1, The insulating layer includes at least one glass fiber layer formed to protrude into the via hole therein, wherein the first glass fiber layer formed to protrude from one side of the via hole is separated from the second glass fiber layer formed to protrude from the other side of the via hole. Printed circuit board, characterized in that. The method according to claim 1, A copper foil layer is laminated on the insulating layer, and the plating layer is formed on the copper foil layer including an inner wall of the via hole. The method according to claim 6, The width of the inlet portion formed by removing the copper foil layer is smaller than the inner width formed by removing the insulating layer. (A) processing a via hole in the insulating layer having a width smaller than an inner width thereof; And (B) performing a plating process on the insulating layer including the inner wall of the via hole, thereby forming a plating layer which forms a void in the via hole by blocking the inlet; Method of manufacturing a printed circuit board comprising a. The method according to claim 8, In the step (A), The via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion. The method according to claim 8, In the step (A), The via hole is a manufacturing method of the printed circuit board, characterized in that the width gradually increases from the inlet toward the inside. The method according to claim 8, In the step (A), The insulating layer includes at least one glass fiber layer impregnated therein, wherein the glass fiber layer is formed to protrude into the via hole. The method of claim 11, And a first glass fiber layer formed to protrude from one side of the via hole is separated from a second glass fiber layer formed to protrude from the other side of the via hole. The method of claim 11, In the step (B), In the glass fiber layer formed to protrude into the via hole, the first plating layer formed on one side of the via hole and the second plating layer formed on the other side of the via hole are connected to each other to form the voids above and below each other. Method of manufacturing a substrate. (A) processing a via hole having a width smaller than an inner width of the inlet portion in the copper-clad laminate in which the copper foil layer is laminated on the insulating layer; And (B) forming a plating layer on the copper foil layer including the inner wall of the via hole to block the inlet to form a void in the via hole; Method of manufacturing a printed circuit board comprising a. The method according to claim 14, In the step (A), The via hole has a maximum width at the center portion, and has a vertically symmetrical structure with respect to the center portion. The method according to claim 14, In the step (A), The via hole is a manufacturing method of the printed circuit board, characterized in that the width gradually increases from the inlet toward the inside. The method according to claim 14, In the step (A), The width of the inlet portion formed by removing the copper foil layer is smaller than the inner width formed by removing the insulating layer. The method according to claim 14, In the step (A), The insulating layer includes at least one glass fiber layer impregnated therein, wherein the glass fiber layer is formed to protrude into the via hole. 19. The method of claim 18, And a first glass fiber layer formed to protrude from one side of the via hole is separated from a second glass fiber layer formed to protrude from the other side of the via hole. 19. The method of claim 18, In the step (B), In the glass fiber layer formed to protrude into the via hole, the first plating layer formed on one side of the via hole and the second plating layer formed on the other side of the via hole are connected to each other to form the voids above and below each other. Manufacturing method.

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