Manufacturing method for roughened copper foil

Abstract

To provide a manufacturing method for roughened copper foil that can form a roughened layer with low roughness and high adhesion on copper foil.SOLUTION: A manufacturing method for roughened copper foil includes the following steps: providing copper foil; and performing an electrolytic process to form a roughened layer on the copper foil. The electrolyte in the electrolytic process contains a copper ion in a range of 0.1 g / L to 20 g / L, a sulfate ion in a range of 30 g / L to 120 g / L, and a coordination compound in a range of 0.1 g / L to 10 g / L.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a roughened copper foil. [Background technology]

[0002] As printed circuit boards (PCBs) become finer, it is desirable to make the roughened layer on the copper foil surface finer, but it is necessary to maintain high adhesion between the copper foil and the insulating resin. Therefore, it is actually difficult to produce a roughened layer on the copper foil with low roughness and high adhesion. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention provides a method for producing a roughened copper foil, which is capable of forming a roughened layer with low roughness and high adhesion on a copper foil. [Means for solving the problem]

[0004] The method for producing a roughened copper foil of the present invention includes the following steps: Providing a copper foil; Carrying out an electrolysis process to form a roughened layer on the copper foil; The electrolyte in the electrolysis process contains copper ions in the range of 0.1 g / L to 20 g / L, sulfate ions in the range of 30 g / L to 120 g / L, and a coordination compound in the range of 0.1 g / L to 10 g / L.

[0005] In one embodiment of the present invention, the coordination compound comprises a benzotriazole-based compound, a propanesulfonic acid-based compound, ethylenediaminetetraacetic acid, or a combination thereof.

[0006] In one embodiment of the present invention, no other metal ions are further added to the electrolyte.

[0007] In one embodiment of the present invention, the electrolysis process includes a first electrolysis process and a second electrolysis process, and a first concentration of copper ions used in the first electrolysis process is lower than a second concentration of copper ions used in the second electrolysis process.

[0008] In one embodiment of the present invention, the first concentration of copper ions is from 0.1 g / L to 10 g / L, and the second concentration of copper ions is from 1 g / L to 20 g / L.

[0009] In one embodiment of the present invention, after performing the electrolytic process, a further silane treatment step is performed.

[0010] In one embodiment of the present invention, the electrolysis process uses direct current.

[0011] In one embodiment of the present invention, the temperature of the electrolysis process is 25°C to 60°C.

[0012] In one embodiment of the present invention, the current density of the electrolysis process is 1 A / dm 2 ~120A / dm 2 It is.

[0013] In one embodiment of the present invention, the duration of the electrolysis process is between 1 second and 45 seconds. Effect of the Invention

[0014] In view of the above, in the present invention, the electrolyte used in forming the roughened layer is improved and contains copper ions in the range of 0.1 g / L to 20 g / L, sulfate ions in the range of 30 g / L to 120 g / L, and coordination compounds in the range of 0.1 g / L to 10 g / L. Therefore, the copper nodules that constitute the roughened layer can be formed by an excellent nucleation and growth mechanism. Therefore, a roughened layer with low roughness and high adhesion can be formed on the copper foil.

[0015] In order to make the foregoing more easily understandable, several embodiments are described in detail below with reference to the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In the following detailed description, for purposes of explanation and not limitation, example embodiments involving specific details are set forth in order to provide a thorough understanding of various principles of the invention. However, it will be apparent to those skilled in the art that, to the benefit of the present invention, the invention may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of various principles of the invention.

[0017] In this specification, ranges expressed as "a certain value to another value" are expressed generally to avoid listing all the values ​​in the range in the specification. Thus, the description of a particular numerical range includes any numerical value and smaller numerical ranges defined by any numerical value in that numerical range, as well as any numerical value and smaller numerical ranges defined by any numerical value in that numerical range.

[0018] Unless otherwise stated, the term "from" as used herein to define a numerical range is intended to encompass ranges equal to and between the recited endpoints. For example, a "size range from a first number to a second number" means that the size range can include the first number, the second number, and any number between the first and second numbers.

[0019] As used herein, non-limiting terms (such as "may," "may," "for example," or other similar terms) are non-required or optional implementations, inclusions, additions, or presences.

[0020] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by those skilled in the art to which the present invention belongs. Furthermore, terms as defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and should not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0021] In this embodiment, the roughened copper foil can be manufactured, for example, by the following steps. First, a copper foil is provided. Then, an electrolytic process is carried out to form a roughened layer on the copper foil. In the present invention, the electrolyte used to form the roughened layer contains copper ions in a range of 0.1 g / L to 20 g / L (e.g., 0.1 g / L, 1 g / L, 10 g / L, 20 g / L, or any value between 0.1 g / L and 20 g / L), sulfate ions (SO4 2- ) in the range of 30 g / L to 120 g / L (e.g., 30 g / L, 50 g / L, 70 g / L, 90 g / L, 120 g / L, or any value between 30 g / L and 120 g / L), and a coordination compound in the range of 0.1 g / L to 10 g / L (e.g., 0.1 g / L, 1 g / L, 3 g / L, 5 g / L, 7 g / L, 10 g / L, or any value between 0.1 g / L and 10 g / L). Therefore, the copper nodules constituting the roughened layer can be formed by an excellent nucleation and growth mechanism such as a high nucleation rate. Therefore, a roughened layer with low roughness and high adhesion (large surface area and high peel resistance) can be formed on the copper foil. Therefore, the surface roughness (e.g., ten-point average roughness (Rz)) of the roughened layer formed is, for example, at least less than 1 μm (micrometer), and the peel resistance between the copper foil on which the roughened layer is formed and the insulating resin (prepreg) is, for example, at least greater than 4 lb / in.

[0022] Furthermore, a coordination compound is added to the electrolyte of the present invention. Therefore, compared with the current electrolytic copper foil that uses only copper (II) sulfate electrolyte, the complex reaction between the coordination compound and copper causes the divalent copper ion (Cu 2+ ) are copper ions of other valences (monovalent copper ions (Cu +) and the like), which can provide an excellent nucleation and growth mechanism and optimize the growth ability of three-dimensional copper nodules. For example, the coordination compound of the present invention includes a benzotriazole (BTA)-based compound (ionic liquid), a propanesulfonic acid-based compound, ethylenediaminetetraacetic acid (EDTA), or a combination thereof. The benzotriazole (BTA)-based compound is, for example, selected from carboxybenzotriazole (CBTA), 1,2,3-benzotriazole, 1-chloro-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-benzotriazole, bis(N-2-ethylhexyl)aminomethylene-1,2,3-tolyltriazole, and bis(N-2-hydroxyethyl)aminomethylene-1,2,3-benzotriazole. The propanesulfonic acid compound is, for example, selected from bis-(3-sulfopropyl)-disulfide disodium salt (SPS) and 3-mercapto-1-propanesulfonic acid (MPS), but the present invention is not limited thereto.

[0023] In some embodiments, the method for producing a roughened copper foil of the present invention can be applied to a circuit board, but the present invention is not limited thereto.

[0024] In some embodiments, no other metal ions are added to the electrolyte. For example, the electrolyte of the present invention does not include metal ions such as iron (Fe) ions or cobalt (Co) ions. That is, the electrolyte includes a single metal ion (copper ion), but the present invention is not limited thereto.

[0025] In some embodiments, the electrolysis process may be performed in multiple stages to effectively obtain the desired copper nodules. For example, the electrolysis process includes a first electrolysis process and a second electrolysis process, and a first concentration of copper ions used in the first electrolysis process is lower than a second concentration of copper ions used in the second electrolysis process. Thereby, first, the copper nodules are vertically grown to a desired range (e.g., dendritic growth) by the first electrolysis process, and then the base portion of the copper nodules (portion close to the copper foil) is thickened by the second electrolysis process, thereby increasing the adhesion between the copper nodules and the copper foil and preventing peeling. The first concentration of copper ions is 0.1 / L to 10 g / L, and the second concentration of copper ions is 1 g / L to 20 g / L, but the present invention is not limited thereto.

[0026] The size and shape of the copper nodules mentioned here can be determined according to actual design requirements. The present invention does not limit the size and shape of the copper nodules, as long as the surface roughness (Rz) of the roughened layer is at least less than 1 μm and the peel resistance between the copper foil on which the roughened layer is formed and the insulating resin (prepreg) is at least greater than 4 lb / in.

[0027] In some embodiments, the thickness of the copper foil is between 1.5 μm and 70 μm, although the invention is not limited thereto.

[0028] In some embodiments, after performing the electrolytic process, a silane treatment step is further performed to form an additional silane coupling layer on the surface of the roughened layer facing the copper foil. This can further improve the adhesion between the roughened layer and other layers in the subsequent process. The silane treatment step can be performed using a silane coupling agent such as acryloyloxypropyltrimethoxysilane, but the present invention is not limited thereto.

[0029] In some embodiments, the operating conditions of the electrolysis process include the use of direct current, the temperature of the electrolysis process is between 25° C. and 60° C. (e.g., 25° C., 35° C., 45° C., 55° C., 60° C., or any temperature between 25° C. and 60° C.), and the current density of the electrolysis process is 1 A / dm 2 (ASD)~120A / dm 2 (For example, 1A / dm 2 , 10A / dm 2 , 30A / dm 2 , 50A / dm 2 , 80A / dm 2 , 120A / dm 2 , or 1A / dm 2 ~120A / dm 2 and the electrolysis process time is 1 second to 45 seconds (for example, 1 second, 10 seconds, 20 seconds, 30 seconds, 45 seconds, or any time between 1 second and 45 seconds), but the present invention is not limited thereto.

[0030] In some embodiments, when a benzotriazole-containing compound is added to the copper bath of the present invention instead of benzotriazole, the surface roughness (Rz) is 1 μm to 1.5 μm and the peel resistance is greater than 4 lb / in. In contrast, when benzotriazole and a benzotriazole-containing compound are not added to the copper bath, the surface roughness (Rz) is 1 μm to 1.5 μm and the peel resistance is less than 3 lb / in. However, the present invention is not limited thereto.

[0031] The effects of the present invention will be described below with reference to examples and comparative examples, but the scope of the present invention is not limited to these examples.

[0032] A copper foil substrate of model number NPG170D was produced using the roughened copper foils produced using the electrolyte compositions of the Examples and Comparative Examples shown in Table 1, and the copper foil substrates were evaluated by the following method.

[0033] Surface roughness (Rz): Measured using a laser or white light.

[0034] Peel Resistance: The peel resistance of metal substrates was measured according to the method described in IPC-TM-650-2.4.8.

[0035] The results of measuring the properties of the produced copper foil substrate are shown in Table 1. Comparing the Examples and Comparative Examples in Table 1, it can be concluded that the addition of a benzotriazole coordination compound can improve peel resistance.

[0036] [Table 1]

[0037] In summary, in the present invention, the electrolyte used in forming the roughened layer is improved and contains copper ions in the range of 0.1 g / L to 20 g / L, sulfate ions in the range of 30 g / L to 120 g / L, and coordination compounds in the range of 0.1 g / L to 10 g / L. Therefore, the copper nodules that constitute the roughened layer can be formed by an excellent nucleation and growth mechanism. Therefore, a roughened layer with low roughness and high adhesion can be formed on the copper foil.

[0038] It will be apparent to one skilled in the art that various modifications and variations can be made to the disclosed embodiments without departing from the scope or spirit of the invention. In view of the above, it is intended that the present invention cover modifications and variations provided they come within the scope of the following claims and their equivalents. [Industrial Applicability]

[0039] The method for producing a roughened copper foil of the present invention can be applied to the production of PCBs.

Claims

1. Providing a copper foil; Carrying out an electrolysis process to form a roughened layer on the copper foil, wherein an electrolyte in the electrolysis process contains copper ions in a range of 0.1 g / L to 20 g / L, sulfate ions in a range of 30 g / L to 120 g / L, and a coordination compound in a range of 0.1 g / L to 10 g / L; The method for producing a roughened copper foil comprises the steps of:

2. The method for producing a roughened copper foil according to claim 1 , wherein the coordination compound comprises a benzotriazole-based compound, a propanesulfonic acid-based compound, ethylenediaminetetraacetic acid, or a combination thereof.

3. The method for producing a roughened copper foil according to claim 1 , wherein no other metal ions are further added to the electrolyte.

4. 2. The method for producing a roughened copper foil according to claim 1, wherein the electrolytic process includes a first electrolytic process and a second electrolytic process, and a first concentration of the copper ions used in the first electrolytic process is lower than a second concentration of the copper ions used in the second electrolytic process.

5. 5. The method for producing a roughened copper foil according to claim 4, wherein the first concentration of copper ions is 0.1 g / L to 10 g / L, and the second concentration of copper ions is 1 g / L to 20 g / L.

6. The method for producing a roughened copper foil according to claim 1 , further comprising performing a silane treatment step after performing the electrolytic process.

7. The method of claim 1 , wherein the electrolytic process uses direct current.

8. The method for producing a roughened copper foil according to claim 1, wherein the temperature of the electrolytic process is 25°C to 60°C.

9. The current density of the electrolysis process is 1 A / dm ２ ~120A / dm ２ The method for producing a roughened copper foil according to claim 1 ,

10. The method for producing a roughened copper foil according to claim 1 , wherein the electrolytic process time is from 1 second to 45 seconds.

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