JP6728545B2 - Printed circuit board and method of manufacturing printed circuit board - Google Patents

Description

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

In recent years, electronic products in which printed circuit boards are used are becoming lighter, thinner, shorter, and smaller. In addition, electronic components mounted on a printed circuit board have been improved in performance.

As a result, the printed circuit board is becoming lighter, thinner, shorter and smaller, and the circuit pattern formed on a predetermined area of the printed circuit board is increasing more and more. In order to improve the density of the circuit pattern, the circuit pattern tends to be finer and finer.

On the other hand, it is necessary to improve the heat dissipation performance of the printed circuit board by improving the density of circuit patterns and improving the performance of electronic components mounted on the printed circuit board. One method for this purpose is to use a metal core.

In the case of a printed circuit board using this metal core, a through hole is generally formed by etching or the like for electrical conduction between layers, and the insulating material filled in this through hole and the metal core are different from each other. Since it is made of a material, research is needed to ensure sufficient mutual adhesion.

Korean Published Patent No. 10-2014-0078197

According to the embodiment of the present invention, the shape of the through hole penetrating the first metal layer and the second metal layer having different etching rates is such that the outer portion of the first metal layer is opened more than the second metal layer. The exposed area is large, and the open area of the central portion of the first metal layer is smaller than that of the second metal layer.

Here, the through hole is filled with an insulating layer, and via the layer penetrating the insulating layer and electrically connecting to the circuit pattern layer, electrical conduction between layers can be performed.

It is a figure which shows the printed circuit board which concerns on one Example of this invention. FIG. 9 is a diagram showing a step for explaining the method of manufacturing the printed circuit board according to the embodiment of the present invention. It is a figure which shows the next process of the process of FIG. It is a figure which shows the next process of the process of FIG. It is a figure which shows the next process of the process of FIG. It is a figure which shows the process next to the process of FIG. It is a figure which shows the process next to the process of FIG. It is a figure which shows the process next to the process of FIG. It is a figure which shows the next process of the process of FIG. It is a figure which shows the next process of the process of FIG.

The terms used in the present application are merely used to describe particular embodiments, and are not intended to limit the present invention. A singular expression includes plural expressions unless otherwise specified in a sentence.

In the present application, when a certain element is “comprising” a certain element, this does not mean that the other element is excluded, and that the other element can be further included unless there is a contrary description. used. Further, throughout the specification, “above” means being located above or below the target portion, and does not necessarily mean being located above with respect to the direction of gravity.

Further, the term "coupling" does not mean that each component is in direct physical contact with each other in the contact relationship between each component, and other configurations are interposed between each component, and It is used as a concept including the case where the constituent elements are in contact with each other.

Further, terms such as “first” and “second” are merely identification symbols for distinguishing the same or corresponding components, and the same or corresponding components are those “first” and “second”. It is not limited by terms such as "."

The sizes and thicknesses of the components shown in the drawings are arbitrarily shown for convenience of description, and the present invention is not necessarily limited to those shown in the drawings.

Hereinafter, an embodiment of a printed circuit board and a method of manufacturing the printed circuit board according to the present invention will be described in detail with reference to the accompanying drawings, and in describing with reference to the accompanying drawings, the same or corresponding components have the same structure. The reference numerals are attached to the drawings, and the duplicated description will be omitted.

FIG. 1 is a diagram showing a printed circuit board according to an embodiment of the present invention.

As shown in FIG. 1, a printed circuit board 1000 according to an exemplary embodiment of the present invention includes a first metal layer 100, a second metal layer 200, and a through hole 300, an insulating layer 400, a circuit pattern layer. 500 and via 600 may be further included.

The first metal layer 100 is a metal layer having a predetermined thickness, and can form a metal core layer together with a second metal layer 200 described later. In this case, the first metal layer 100 uses a metal having a predetermined expansion coefficient such as an invar, which has a relatively low expansion coefficient, to prevent warpage of the printed circuit board 1000 and to dissipate heat. The performance can be improved.

The second metal layer 200 has an etching rate different from that of the first metal layer 100 and is formed on both surfaces of the first metal layer 100, and forms a metal core layer together with the first metal layer 100 described above. be able to. In particular, since the second metal layer 200 has different etching rates from the first metal layer 100, the degree of etching of the first metal layer 100 and the second metal layer 200 may be different with respect to a specific etching solution. ..

In this case, the second metal layer 200 may be made of a metal, such as copper foil, which is relatively easy to mold and process, so that the printed circuit board 1000 can be manufactured more easily.

On the other hand, as a method of forming the second metal layer 200 on both surfaces of the first metal layer 100, the second metal layer 200 is laminated on both surfaces of the first metal layer 100 and then pressure-bonded, or the first metal layer is formed. Various methods can be used, such as forming a seed layer on 100 and then electroplating copper to form second metal layer 200.

The through hole 300 is formed by penetrating the first metal layer 100 and the second metal layer 200, and the outer portion of the first metal layer 100 has a larger open area than the second metal layer 200. The central area of the layer 100 is formed to have a smaller open area than the second metal layer 200.

That is, as shown in FIG. 1, the open width of the central portion of the first metal layer 100 in the through hole 300 is smaller than the open width of the second metal layer 200. The open width of the boundary with the second metal layer 200 is larger than the open width of the second metal layer 200, and the cross-section of the through hole 300 is formed into a shape including an hourglass shape. To be done.

As a result, the overall surface area of the through hole 300 becomes relatively large, and an anchor effect can be exerted by the protruding portion and the recessed portion.

The insulating layer 400 is formed on the second metal layer 200 while being filled in the through holes 300. Is the insulating layer 400 coated on the inside of the through holes 300 and on the second metal layer 200 as a liquid such as a resin? The film may be formed in a solid state such as a film by being attached to the inside of the through-hole 300 and the second metal layer 200, and various configurations may be performed as necessary.

As described above, in the printed circuit board 1000 according to the present embodiment, the contact area of the first metal layer 100 and the second metal layer 200 with the insulating layer 400 in the through hole 300 can be increased, and the anchor effect can be obtained. Can be demonstrated. Therefore, it is possible to further improve the adhesion between the metal core layer formed of the first metal layer 100 and the second metal layer 200 and the insulating layer 400.

The circuit pattern layer 500 may be composed of a circuit formed on the insulating layer 400 to perform a predetermined function such as a signal pattern, a power supply pattern, and a ground pattern. Each of the circuit pattern layers 500 will be described later. Conduction can be achieved by the via 600 and the like.

Meanwhile, the number and arrangement of the circuit pattern layer 500 and the insulating layer 400 can be variously configured according to the type and application of the printed circuit board 1000, and the structure of the printed circuit board 1000 shown in FIG. 1 is merely an example. It is not necessarily limited to this.

The via 600 penetrates the insulating layer 400 filled in the through hole 300 and is electrically connected to the circuit pattern layer 500. After forming a via hole penetrating the insulating layer 400, the via 600 is formed by plating or the like. Can be formed.

By using such a via 600, the printed circuit board 1000 according to the present embodiment can obtain electrical conduction between both surfaces of the metal core layer including the first metal layer 100 and the second metal layer 200. it can.

In the printed circuit board 1000 according to the present embodiment, the through hole 300 may be formed to have a continuous inclined surface from the outer portion of the first metal layer 100 to the central portion of the first metal layer 100. That is, as shown in FIG. 1, the portion protruding from the first metal layer 100 into the through hole 300 may be formed in a triangular shape.

Accordingly, the stress in the portion where the first metal layer 100 and the insulating layer 400 are in contact with each other in the through hole 300 can be uniformly dispersed, and thus it is possible to minimize the concentration of the stress in a specific portion and easy deformation. it can.

2 to 10 are views sequentially showing a manufacturing process for explaining a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

2 to 10, a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention includes a second metal layer having an etching rate different from that of the first metal layer 100 on both surfaces of the first metal layer 100. Beginning with the step of forming 200 (see FIG. 2).

Here, as a method of forming the second metal layer 200 on both surfaces of the first metal layer 100, the second metal layer 200 is laminated on both surfaces of the first metal layer 100 and then pressure-bonded, or the first metal layer 100 is formed. Various methods can be used, such as forming a seed layer on layer 100 and then copper electroplating to form second metal layer 200.

Then, the first dry film 10 is formed on the second metal layer 200 formed on one surface of the first metal layer 100 (see FIG. 3 ). In this case, the first dry film 10 is a photosensitive resin layer such as a PIPD (Photo Imageable Polymer Dielectric) and may serve as a mask when etching is performed in a subsequent process.

Next, a part of the first dry film 10 is removed so that a part of the second metal layer 200 is exposed (see FIG. 3). That is, a part of the first dry film 10 corresponding to the position where the through hole 300 is formed is removed. In this case, the first dry film 10 formed of the photosensitive resin layer can be partially removed by the exposure and development processes.

Next, half or more of the area of the cross section of the first metal layer 100 and the second metal layer 200 are etched with respect to the removed portion of the first dry film 10 (see FIG. 4).

Specifically, when an etching liquid is added to the removed portion of the first dry film 10, the portion of the second metal layer 200 that is in contact with the etching liquid is etched. Then, the etchant that has flowed through the second metal layer 200 starts etching the portion of the first metal layer 100 that contacts the etchant.

At this time, since the etching rates of the first metal layer 100 and the second metal layer 200 are different from each other, when the etching liquid contacts the first metal layer 100, the etching rate of the second metal layer 200 is higher than that of the second metal layer 200. It can be etched rapidly. As a result, abrupt etching occurs at the interface between the first metal layer 100 and the second metal layer 200, and the open area of the outer shell of the first metal layer 100 is larger than the open area of the second metal layer 200. Can be big.

On the other hand, since the etchant is introduced from the outer portion of the first metal layer 100 to the central portion while gradually etching the first metal layer 100, the first metal layer 100 is continuously fed from the outer portion to the central portion. It can be formed with an inclined surface, and the open area of the central portion of the first metal layer 100 can be smaller than the open area of the second metal layer 200.

Next, the second dry film 20 is formed on the second metal layer 200 formed on the other surface of the first metal layer 100 (see FIG. 6). That is, the second dry film 20 is formed on the opposite surface of the surface opposite to the surface etched in the above process. In this case, the second dry film 20 is also a photosensitive resin layer such as PIPD, and can serve as a mask when etching is performed in a subsequent process.

Meanwhile, as shown in FIG. 6, for the convenience of the process, the process of forming the second dry film 20 may be performed by turning over the printed circuit board 1000 being manufactured and continuing the subsequent process.

Then, a part of the second dry film 20 is removed so that a part of the second metal layer 200 is exposed (see FIG. 6). That is, a part of the second dry film 20 corresponding to the position where the through hole 300 is formed is removed. In this case, the second dry film 20, which is the photosensitive resin layer, can also be partially removed by the exposure and development steps.

Next, with respect to the removed portion of the second dry film 20, the remaining region on the cross section of the first metal layer 100 and the second metal layer 200 are etched (see FIG. 7 ). That is, by performing the same process as the above-described etching process on the opposite surface, the through hole 300 as shown in FIG. 7 can be formed.

As described above, the through-hole 300 formed by the method of manufacturing the printed circuit board according to the present embodiment has a relatively large overall surface area, and the projected portion and the recessed portion have an anchor effect. Can be demonstrated.

The method of manufacturing the printed circuit board according to the present embodiment may further include a step of removing the remaining portions of the first dry film 10 and the second dry film 20 (FIGS. 5 and 8). That is, the remaining portions of the first dry film 10 and the second dry film 20 that are no longer needed can be removed after the role of the mask. In this case, the first dry film 10 and the second dry film 20 can be peeled and removed by a strip process or the like.

The method of manufacturing a printed circuit board according to the present embodiment fills the etched portions of the first metal layer 100 and the second metal layer 200 and forms the insulating layer 400 on the second metal layer 200 (FIG. 9). Reference) can be further included.

In this case, the insulating layer 400 may be applied as a liquid such as a resin inside the through hole 300 and on the second metal layer 200, or may be a solid like a film inside the through hole 300 and the second metal layer 200. It can be configured in various ways according to need, such as being formed by being attached on top.

As described above, in the method of manufacturing the printed circuit board according to the present embodiment, the contact area of the first metal layer 100 and the second metal layer 200 in the through hole 300 with the insulating layer 400 can be increased, The anchor effect can be demonstrated. Therefore, the adhesion between the metal core layer formed of the first metal layer 100 and the second metal layer 200 and the insulating layer 400 can be improved.

The method for manufacturing a printed circuit board according to the present embodiment includes a step of forming a via 600 penetrating the insulating layer 400 filled in the first metal layer 100 and the second metal layer 200, and on the second metal layer 200. Forming the circuit pattern layer 500 electrically connected to the via 600 (see FIG. 10).

In this case, the circuit pattern layer 500 can be a circuit for performing a predetermined function such as a signal pattern, a power supply pattern, and a ground pattern formed on the insulating layer 400, and the circuit pattern layer 500 of each layer. Can be conducted by the via 600 or the like. That is, by using the via 600, electrical conduction can be obtained between both surfaces of the metal core layer composed of the first metal layer 100 and the second metal layer 200.

In the method of manufacturing the printed circuit board according to the present embodiment, the step of etching the first metal layer 100 and the second metal layer 200 is performed on the surface opposite to the surface on which the first dry film 10 and the second dry film 20 are formed. The backup material 30 may be formed (see FIGS. 3, 4, 6, and 7).

In this case, the backup material 30 is a member for supporting the bottom surface of the printed circuit board 1000 being manufactured and preventing the metal layers 100 and 200 from being separated after etching, and is removed after the etching is completed. it can.

Although one embodiment of the present invention has been described above, a person having ordinary knowledge in the technical field may add or change a component within a range not departing from the idea of the present invention described in the claims, The present invention can be variously modified and changed by deleting or adding, and it can be said that the present invention is also included in the scope of the present invention.

10, 20 Dry film 30 Backup material 100 First metal layer 200 Second metal layer 300 Through hole 400 Insulating layer 500 Circuit pattern layer 600 Via 1000 Printed circuit board

Claims (9)

A first metal layer,
Second metal layers having etching rates different from those of the first metal layer and formed on both surfaces of the first metal layer;
The first metal layer and the second metal layer are formed so as to penetrate therethrough. Is a through hole formed to have a smaller open area than the second metal layer,
Printed circuit board including. The printed circuit board of claim 1, further comprising an insulating layer formed on the second metal layer while being filled in the through hole. A circuit pattern layer formed on the insulating layer,
The printed circuit board according to claim 2, further comprising: a via penetrating the insulating layer filled in the through hole and electrically connecting to the circuit pattern layer. The printed circuit board according to any one of claims 1 to 3, wherein the through hole is formed on a continuous inclined surface from an outer portion of the first metal layer to a central portion of the first metal layer. .. Forming a second metal layer having etching rates different from those of the first metal layer on both surfaces of the first metal layer;
Forming a first dry film on the second metal layer formed on one surface of the first metal layer;
Removing a portion of the first dry film so that a portion of the second metal layer is exposed;
Etching at least a half region on the cross section of the first metal layer and the second metal layer with respect to the removed portion of the first dry film;
Forming a second dry film on the second metal layer formed on the other surface of the first metal layer;
Removing a portion of the second dry film so that a portion of the second metal layer is exposed;
Etching the remaining area on the cross section of the first metal layer and the second metal layer with respect to the removed portion of the second dry film;
Only including,
In each of the etching steps, the outer portion of the first metal layer has a larger open area than the second metal layer, and the central portion of the first metal layer has a larger open area than the second metal layer. A method of manufacturing a printed circuit board, which is etched to form a small area . The method of claim 5, further comprising removing the remaining portions of the first dry film and the second dry film. The method of claim 6, further comprising filling the etched portions of the first metal layer and the second metal layer to form an insulating layer on the second metal layer. Forming a via through the insulating layer filled in the first metal layer and the second metal layer;
Forming a circuit pattern layer electrically connected to the via on the second metal layer;
The method for manufacturing a printed circuit board according to claim 7, further comprising: Etching the first metal layer and the second metal layer,
The method for manufacturing a printed circuit board according to claim 5, wherein a backup material is formed on a surface opposite to the surface on which the first dry film and the second dry film are formed.

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