KR100990575B1 - Printed circuit board with fine pattern and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a printed circuit board having a fine pattern and a method of manufacturing the same, wherein a surface roughness is formed on the shiny surface on a region where a circuit pattern of copper foil having a mat surface and a shiny surface is to be formed, and the first substrate is formed on a base substrate. The copper foil disposed with the insulating layer and the shiny surface facing the insulating layer is sequentially arranged and stacked, and then the surface roughness of the copper foil surface removed by etching is reduced by using a subtractive method or a modified additive method. It is possible to implement the fine pattern by reducing the over-etching on the circuit pattern by forming to facilitate the etching.

Fine pattern, matte surface, shiny surface, surface roughness, electrolytic copper foil, photosensitive resist

Description

Printed circuit board having fine pattern and manufacturing method of the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board having a fine pattern and a method of manufacturing the same, and more particularly, to a printed circuit board having a fine pattern using a space separation method for forming a low surface roughness of a copper foil surface removed by etching, and a manufacturing method thereof. It is about a method.

In general, a printed circuit board is wired to one side or both sides of a board made of various thermosetting synthetic resins, and then ICs and electronic components are disposed and fixed on the boards, and electrical wiring therebetween is coated with an insulator.

In recent years, with the development of the electronic industry, the demand for high functionalization of electronic components has increased rapidly, and printed circuit boards on which such electronic components are mounted have also required high density wiring. Accordingly, researches on circuit forming methods for forming electric wirings, particularly circuit formation methods capable of implementing fine circuit patterns, have been actively conducted in the process of manufacturing printed circuit boards.

As one example of a conventional circuit forming method, a subtractive process is a circuit forming method of a printed circuit board which forms a circuit pattern by selectively removing unnecessary portions other than a circuit pattern on an insulating substrate coated with copper foil by etching or the like. . 1 to 4 are cross-sectional views for each process for explaining a circuit forming method through a conventional subtractive method, and the circuit forming method will be described with reference to the following.

First, the copper foil 13 which has the insulating layer 12, the matte side 13a, and the shiny side 13b is sequentially arrange | positioned and laminated on the base substrate 11. At this time, in order to increase the adhesive force between the copper foil 13 and the insulating layer 12, the mat surface 13a and the insulating layer 12 of the copper foil 13 are bonded (FIG. 1).

Next, the photosensitive resist 14 is coated on the copper foil 13 using a D / F method or a liquid photosensitive material method, and the photosensitive resist 14 is patterned so that the region of the copper foil 13 on which the circuit pattern is to be formed is exposed. (FIG. 2).

Next, the unnecessary copper foil 13 is removed by etching using the patterned photosensitive resist 14 (FIG. 3).

Finally, the circuit pattern 15 is formed by removing the photosensitive resist 14 (FIG. 4).

However, when using this method, the ability to form a fine pattern is affected by the thickness of the copper foil 13 and the resolution of the photosensitive resist 14. In general, when using a mechanism for etching the copper foil 13, the copper foil 13 may be used. Since it has an aspect ratio of about 2.0 with respect to the thickness of), for example, when the thickness of the copper foil 13 is 10 μm, it is difficult to implement a fine pattern with L / S = 20/20 μm as a limit. .

In addition, since the copper foil 13 to be a circuit pattern is overetched in the process of etching the unnecessary copper foil 13, there is a difficulty in implementing a fine pattern, improving line width accuracy, and stabilizing impedance.

In another example of a conventional circuit forming method, a modified semi-additive process (MSAP) is a method of stacking copper foil on an insulating substrate, removing the copper foil in a thickness direction, and performing electrolytic copper plating thereon. A circuit forming method of a printed circuit board forming a circuit pattern. 5 to 10 are cross-sectional views for each process for explaining a circuit formation method through a conventional modified semi-additive method, which will be described below with reference to the circuit formation method.

First, the copper foil 23 which has the insulating layer 22, the mat surface 23a, and the shiny surface 23b is sequentially arrange | positioned and laminated on the base substrate 21. FIG. At this time, in order to increase the adhesive force between the insulating layer 22 and the copper foil 23, the mat surface 23a and the insulating layer 22 of the copper foil 23 are bonded (FIG. 5).

Next, the copper foil 23 is partially cut in the thickness direction (FIG. 6). Here, the cut copper foil 23 is used as a lead wire for electrolytic copper plating as mentioned later.

Next, the photosensitive resist 24 is apply | coated on the copper foil 23, and the photosensitive resist 24 is patterned so that the area | region in which the circuit pattern will be formed in the copper foil 23 is exposed (FIG. 7).

Next, electrolytic copper plating is performed on the exposed copper foil 25 to form an electrolytic copper plating layer 25 (FIG. 8).

Next, the photosensitive resist 24 is removed (Fig. 9).

Finally, the copper foil of the area | region where the electrolytic copper plating layer on the insulating layer 22 is not formed is removed, and the circuit pattern 26 is formed (FIG. 10).

However, when using this method, since the portion of the circuit pattern 26 is overetched in forming the circuit pattern 26 by removing the copper foil in the region where the electrolytic copper plating layer is not formed, L / Since S = 15 / 15㎛, there was a difficulty in implementing a fine circuit pattern.

On the other hand, in the case of using the subtractive method or the modified additive method as described above, when the unnecessary copper foil is removed by etching, the adhesion strength between the copper foil and the insulating layer is required. There was also.

In order to solve this problem, a method of using ultra thin copper (UTC) has been proposed, but there has been a problem in that the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reduce the overetching by facilitating etching by using a space separation method for forming a low surface roughness of the copper foil surface removed by etching. It is to provide a printed circuit board having a fine pattern by the process and a manufacturing method thereof.

A printed circuit board having a fine pattern according to an exemplary embodiment of the present invention includes a first insulating layer formed on a base substrate and a circuit pattern formed on the first insulating layer, wherein the circuit is in contact with the first insulating layer. Surface roughness is formed on one surface of the pattern smaller than the width of the circuit pattern.

According to a first aspect of the present invention, there is provided a method of manufacturing a printed circuit board having a fine pattern, the method comprising: (A) forming surface roughness on the shiny surface on a region where a circuit pattern is to be formed in a copper foil having a matt surface and a shiny surface; (B) sequentially placing and laminating the copper foil having the first insulating layer and the shiny surface facing the insulating layer on the base substrate, and (C) patterning the copper foil to form a circuit pattern Characterized in that it comprises a step.

At this time, the step (A), (A1) preparing a copper foil having a mat surface and a shiny surface, (A2) laminating a photosensitive resist on the shiny surface of the copper foil, (A3) the circuit pattern of the copper foil Patterning the photosensitive resist to expose the region to be formed, and (A4) forming surface roughness on the exposed copper foil.

In addition, in the step (A3), the photosensitive resist is patterned so that a smaller area of the copper foil than the area where the circuit pattern is to be formed is exposed.

In addition, the (C) step, (C1) laminating a photosensitive resist on the mat surface of the copper foil, (C2) patterning the photosensitive resist to expose a region in which the circuit pattern of the copper foil is to be formed, (C3) etching the exposed copper foil, and (C4) removing the photosensitive resist.

In addition, after the step (C), (D) characterized in that it comprises the step of laminating a second insulating layer on the first insulating layer.

According to a second aspect of the present invention, there is provided a method of manufacturing a printed circuit board having a fine pattern, the method comprising: (A) forming surface roughness on the shiny surface on a region where a circuit pattern is to be formed in a copper foil having a matt surface and a shiny surface; (B) sequentially placing and laminating the copper foil disposed on the base substrate such that the insulating layer and the shiny surface face the insulating layer, and (C) partially removing and removing the copper foil in the thickness direction. Forming a surface roughness on a surface, (D) laminating a photosensitive resist on the copper foil, and patterning the photosensitive resist to expose a region in which the circuit pattern is to be formed in the copper foil, (E) on the exposed copper foil Performing electrolytic copper plating, removing the photosensitive resist, and (F) removing the copper foil partially removed in the thickness direction. .

At this time, the step (A), (A1) preparing a copper foil having a mat surface and a shiny surface, (A2) laminating a photosensitive resist on the shiny surface of the copper foil, (A3) the circuit pattern of the copper foil Patterning the photosensitive resist to expose the region to be formed, and (A4) forming surface roughness on the exposed copper foil.

In addition, in the step (A3), the photosensitive resist is patterned so that a smaller area of the copper foil than the area where the circuit pattern is to be formed is exposed.

Further, in the step (F), the copper foil is characterized in that it is removed by flash etching (soft etching).

In addition, after the step (F), (G) characterized in that it comprises the step of laminating a second insulating layer on the first insulating layer.

The present invention not only reduces the etching time by using a space separation method of forming a low surface roughness of the copper foil surface removed by etching, but also reduces overetching of the circuit pattern, thereby enabling the implementation of a fine pattern.

In addition, the present invention enables the implementation of a fine pattern using a general copper foil without the need for using a specially processed expensive ultra-thin copper foil.

In addition, the present invention improves adhesiveness by adhering a shiny surface having a part of surface roughness formed on the insulating layer, and adheres a photosensitive resist or insulating layer to a mat surface on which surface roughness is formed, thereby eliminating a separate roughness forming process.

In addition, the present invention enables the implementation of a fine pattern in consideration of a process error by forming a surface roughness in a region smaller than the width of the circuit pattern on one surface of the circuit pattern in contact with the first insulating layer.

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 adding reference numerals to the components of each drawing, it should be noted that the same components as much as possible, even if displayed on the other drawings. 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.

11 to 18 are cross-sectional views for each process for describing a method of manufacturing a printed circuit board having a fine pattern according to a first embodiment of the present invention. same.

First, as shown in FIG. 11, the copper foil 101 which has the mat surface 101a and the shiny surface 101b is prepared.

At this time, the copper foil 101 is manufactured using a general milling machine, and the copper foil 101 which has the matte surface 101a which is not polished and the shiny shiny surface 101b is manufactured through this milling machine.

Here, the electrolytic copper foil using the milling machine produces electrolytic copper foil by thickness by depositing copper on the drum by the continuous chemical reaction of oxidation and reduction of the copper plating solution by flowing +/- current inside / outside the rotating drum using electrolytic copper plating. It is formed using the principle, and a detailed description thereof will be omitted.

Next, as shown in FIG. 12, after apply | coating the photosensitive resist 102 to the shiny surface 101b of the copper foil 101, the photosensitive resist was used using the art work film by which the predetermined | prescribed pattern was printed. The 102 is exposed and developed to pattern the exposed region of the circuit pattern.

At this time, the photosensitive resist 102 adheres the artwork film printed with a predetermined pattern onto the photosensitive resist, and then irradiates with ultraviolet rays to remove the uncured photosensitive resist in the region where the pattern does not pass through the developer using a developer. By patterning.

Here, it is preferable that the photosensitive resist 102 is patterned so that the area | region smaller than the width | variety of the area | region P which becomes a circuit pattern among the copper foils 101 is exposed. This is to form the surface roughness in the area smaller than the width of the circuit pattern, to consider the process error during the circuit pattern forming process.

Next, as shown in FIG. 13, the surface roughness is formed on the surface of the copper foil 101 exposed to the outside without the photosensitive resist 102 formed thereon, and the applied photosensitive resist 102 is peeled off and removed. do.

At this time, the surface roughness is formed through general mechanical polishing, chemical polishing, electrolytic polishing. Here, the mechanical polishing is a method of smoothing the surface of the copper foil by using a buff, etc. However, in the case of using a thin copper foil, the mechanical foil may be damaged by applying mechanical stress to the copper foil. It is suitable for use on the surface. On the other hand, in the case of chemical polishing and electropolishing, since mechanical stress does not occur on copper foil unlike mechanical polishing, even relatively thin copper foil is not damaged by chemical polishing and electropolishing, so that chemical polishing and electropolishing are used for the surface of a relatively thin copper foil. Suitable.

In addition, the photosensitive resist 102 is removed using a stripping solution such as sodium hydroxide (NaOH) or potassium hydroxide (KOH).

That is, the present embodiment is characterized in that the surface roughness is formed only on a part of the region to be a circuit pattern without forming a separate surface roughness on the surface of the copper foil removed by etching of the copper foil.

Next, as shown in FIG. 14, the copper foil 101 is arrange | positioned and laminated | stacked on the base substrate 103 so that the 1st insulating layer 104 and the shiny surface 101b may face the 1st insulating layer 104. Next, as shown in FIG. .

At this time, in the present embodiment, unlike the prior art, the first surface of the insulating layer 104 is laminated so that the shiny surface 101b of the copper foil 101 is in contact. Here, the area P, which will be the circuit pattern on which the surface roughness is formed, of the shiny surface 101b adhered to the first insulating layer 104 has a larger area in contact with the first insulating layer 104, so that no surface roughness is formed. It is more firmly coupled with the first insulating layer 104 than the non-region.

Next, as shown in FIG. 15, the photosensitive resist 105 is apply | coated on the mat surface 101a of the copper foil 101, and the photosensitive resist 105 is exposed so that the area | region in which the circuit pattern will be formed in the copper foil 101 is exposed. Pattern.

In this case, when the photosensitive resist 105 is applied to the copper foil, according to the prior art, since the photosensitive resist 105 is applied to the shiny surface without surface roughness, a process of forming a separate surface roughness on the shiny surface to increase adhesiveness is performed. Although required, in this embodiment, since the photosensitive resist 105 is applied on the mat surface 101a of the copper foil 101, the adhesion between the copper foil and the photosensitive resist 102 is improved without a separate surface roughness forming process.

On the other hand, in the case of patterning the photosensitive resist 105, the patterning at a desired position often occurs due to a process error. In this case, the region P to be the circuit pattern having the surface roughness formed on the shiny surface 101b and the region to be the circuit pattern defined by applying the photosensitive resist 105 on the mat surface 101a do not coincide with each other. Therefore, when the copper foil 101 to which the photosensitive resist 105 is not applied is removed by etching based on the photosensitive resist 105 applied to the mat surface 101a, the circuit pattern of the shiny surface 101b having the surface roughness formed thereon. At least a part of the region P to be made has to be removed by etching. Further, since the etching time is further required to remove the region coupled with the first insulating layer 104 by the surface roughness, the region to be the circuit pattern is overetched, making it difficult to implement the fine pattern. However, as described in the description of FIG. 12, the over-etching problem is minimized due to the occurrence of such a process error by forming surface roughness in a region smaller than the region to be a circuit pattern of the shiny surface 101b.

Next, as shown in FIG. 16, the copper foil 101 exposed to the outside without forming the photosensitive resist 105 is removed by flash-etching.

In this case, since the surface roughness of the shiny surface 101b of the copper foil 101 adhered to the first insulating layer 104 is formed only in the region where the circuit pattern is to be formed, the exposed copper foil 101 is formed of the first insulating layer ( 104 and the low adhesive strength not only shortens the etching time but also reduces overetching of the copper foil 101 in the region where the circuit pattern is to be formed.

Next, as shown in FIG. 17, the applied photosensitive resist 105 is removed to form a circuit pattern 107. At this time, the photosensitive resist 105 is removed using a stripping solution such as sodium hydroxide (NaOH) or potassium hydroxide (KOH).

Next, as shown in FIG. 18, a second insulating layer 108 is formed on the first insulating layer 104. At this time, since the upper surface of the circuit pattern 107 is a mat surface having a surface roughness, the adhesive strength with the second insulating layer 108 is high, so that a separate roughness forming process is not required, thereby simplifying the manufacturing process and reducing the manufacturing time. It becomes possible.

On the other hand, a printed circuit board according to a preferred embodiment of the present invention is manufactured by such a manufacturing process. That is, in the printed circuit board according to the present invention, the first insulating layer 104 and the circuit pattern 107 are formed on the base substrate 103 and one surface of the circuit pattern 107 in contact with the first insulating layer 104. Is characterized in that the surface roughness is formed in a region smaller than the width of the circuit pattern 107. By adopting such a structure, it is possible to implement a fine pattern while considering the process error.

19 to 25 are cross-sectional views illustrating a manufacturing method of a printed circuit board having a fine circuit pattern according to a second exemplary embodiment of the present invention. Referring to this, a manufacturing method according to the present exemplary embodiment will be described below. Is the same as Here, duplicate descriptions of components and manufacturing processes identical or corresponding to those of the first embodiment will be omitted.

First, as shown in FIG. 19, the first insulating layer 204 and the shiny surface 201b are formed on the base substrate 203 by performing the same process as that shown in FIGS. 11 to 14. The copper foil 201 is arrange | positioned so that it may face to 204, and is laminated.

Next, as shown in FIG. 20, the copper foil 201 is partially cut in the thickness direction. Here, the cut copper foil 201 is used as a lead wire for electrolytic copper plating as described later.

Next, as shown in FIG. 21, the photosensitive resist 205 is apply | coated on the copper foil 201, and the photosensitive resist 205 is patterned so that the area | region in which the circuit pattern will be formed in the copper foil 201 is exposed.

Next, as shown in FIG. 22, the electrolytic copper plating layer 206 is formed by electrolytic copper plating on the exposed copper foil 201. At this time, the electrolytic copper plating is carried out by using a DC rectifier after depositing in the copper plating working cylinder, it is preferable to use a method of calculating the area to be plated by applying a suitable current to the DC rectifier to deposit gold.

Next, as shown in FIG. 23, the photosensitive resist 205 is removed.

Next, as shown in FIG. 24, the copper foil of the area | region in which the electrolytic copper plating layer on the 1st insulating layer 204 was not formed is removed by flash-etching, and the circuit pattern 207 is formed. At this time, since the surface roughness is formed only in the region where the circuit pattern is to be formed on the shiny surface of the copper foil 201 bonded to the first insulating layer 204, the exposed copper foil 201 may be separated from the first insulating layer 204. The low adhesive force not only shortens the etching time but also reduces overetching of the copper foil 201 in the region where the circuit pattern is to be formed.

Finally, as shown in FIG. 25, a second insulating layer 208 is formed on the first insulating layer 204.

On the other hand, a printed circuit board according to a preferred embodiment of the present invention is manufactured by such a manufacturing process. That is, in the printed circuit board according to the present invention, the first insulating layer 204 and the circuit pattern 207 are formed on the base substrate 203 and one surface of the circuit pattern 207 in contact with the first insulating layer 204. Is characterized in that the surface roughness is formed in a region smaller than the width of the circuit pattern 207. By adopting such a structure, it is possible to implement a fine pattern while considering the process error.

Although the present invention has been described in detail through specific embodiments, this is for explaining the present invention in detail, and a printed circuit board having a fine pattern according to the present invention and a method of manufacturing the same are not limited thereto, and the technical spirit of 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 cross-sectional views of respective processes for explaining a circuit forming method through a conventional subtractive method.

5 to 10 are cross-sectional views of respective processes for explaining a circuit formation method through a conventional modified semi-additive method.

11 to 18 are cross-sectional views of processes for describing a method of manufacturing a printed circuit board having a fine circuit pattern according to a first embodiment of the present invention.

19 to 25 are cross-sectional views illustrating processes for manufacturing a printed circuit board having a fine circuit pattern according to a second exemplary embodiment of the present invention.

≪ Description of reference numerals &

101, 201: copper foil 101a, 201a: mat surface

101b and 201b: shiny surface 102 and 205: photosensitive resist

103, 203: base substrate 104: 204: first insulating layer

206: electrolytic copper foil layers 107, 207: circuit pattern

108,208: second insulating layer

Claims (11)

A first insulating layer formed on the base substrate; And Circuit pattern formed on the first insulating layer Including, Printed circuit board having a fine pattern, characterized in that the surface roughness is formed in a region smaller than the width of the circuit pattern on one surface of the circuit pattern in contact with the first insulating layer. (A) forming surface roughness on the shiny surface on the region where the circuit pattern is to be formed in the copper foil having the matt surface and the shiny surface; (B) sequentially arranging and laminating the copper foil disposed on the base substrate such that the first insulating layer and the shiny surface face the first insulating layer; And (C) patterning the copper foil to form a circuit pattern Method of manufacturing a printed circuit board having a fine pattern comprising a. The method according to claim 2, Step (A) is (A1) preparing a copper foil having a mat surface and a shiny surface; (A2) laminating a photosensitive resist on the shiny surface of the copper foil; (A3) patterning the photosensitive resist to expose a region where a circuit pattern of the copper foil is to be formed; And (A4) forming surface roughness on the exposed copper foil Method of manufacturing a printed circuit board having a fine pattern comprising a. The method according to claim 3, In the step (A3), The photosensitive resist is a method of manufacturing a printed circuit board having a fine pattern, characterized in that to expose the area smaller than the area of the copper pattern to form the circuit pattern. The method according to claim 2, Step (C) is (C1) laminating a photosensitive resist on the mat surface of the copper foil; (C2) patterning the photosensitive resist to expose a region where a circuit pattern of the copper foil is to be formed; (C3) etching the exposed copper foil; And (C4) removing the photosensitive resist Method of manufacturing a printed circuit board having a fine pattern comprising a. The method according to claim 2, After the step (C), (D) stacking a second insulating layer on the first insulating layer Method of manufacturing a printed circuit board having a fine pattern comprising a. (A) forming surface roughness on the shiny surface on the region where the circuit pattern is to be formed in the copper foil having the matt surface and the shiny surface; (B) sequentially arranging and laminating the copper foil disposed on the base substrate such that the first insulating layer and the shiny surface face the first insulating layer; And (C) removing a part of the copper foil in the thickness direction and forming surface roughness on the removed surface; (D) laminating a photosensitive resist on the copper foil, and patterning the photosensitive resist to expose a region in which the circuit pattern is to be formed in the copper foil; (E) performing electrolytic copper plating on the exposed copper foil and removing the photosensitive resist; And (F) removing the copper foil partially removed in the thickness direction Method of manufacturing a printed circuit board having a fine pattern comprising a. The method of claim 7, Step (A) is (A1) preparing a copper foil having a mat surface and a shiny surface; (A2) laminating a photosensitive resist on the shiny surface of the copper foil; (A3) patterning the photosensitive resist to expose a region where a circuit pattern of the copper foil is to be formed; And (A4) forming surface roughness on the exposed copper foil Method of manufacturing a printed circuit board having a fine pattern comprising a. The method according to claim 8, In the step (A3), The photosensitive resist is a method of manufacturing a printed circuit board having a fine pattern, characterized in that to expose the area smaller than the area of the copper pattern to form the circuit pattern. The method of claim 7, In the step (F), the copper foil is removed by flash etching (flash etching), characterized in that the manufacturing method of a printed circuit board having a fine pattern. The method of claim 7, After the step (F), (G) stacking a second insulating layer on the first insulating layer Method of manufacturing a printed circuit board having a fine pattern comprising a.

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