Method for manufacturing 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 manufacturing a roughened copper foil.

Background Art

[0002] With the miniaturization of printed circuit boards (PCBs), 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 manufacture a roughened layer with low roughness and high adhesion on the copper foil.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The present invention provides a method for manufacturing a roughened copper foil capable of forming a roughened layer with low roughness and high adhesion on the copper foil.

Means for Solving the Problems

[0004] The method for manufacturing a roughened copper foil of the present invention includes the following steps. Provide a copper foil. Perform an electrolysis process to form a roughened layer on the copper foil. The electrolytic solution 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 complex compound in the range of 0.1 g / L to 10 g / L.

[0005] In one embodiment of the present invention, the complex compound includes 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 electrolytic solution.

[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 electrolysis process, a silane treatment step is further performed.

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

[0011] In one embodiment of the present invention, the temperature of the electrolysis process is from 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 ~120 A / dm 2 is.

[0013] In one embodiment of the present invention, the time of the electrolysis process is from 1 second to 45 seconds.

Advantages of the Invention

[0014] Based on the above, in the present invention, the electrolytic solution used when 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 constituting 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] To make the above content easier to understand, several embodiments will be described in detail below with reference to the drawings.

Embodiments for Carrying Out the Invention

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

[0017] As used herein, a range represented by "a numerical value to another numerical value" is schematically presented to avoid listing all the numerical values within that range in the specification. Thus, the recitation of a particular numerical range includes any numerical value within that range and any smaller numerical ranges defined by any numerical value within that range, as well as any numerical value and any smaller numerical ranges in the specification similar to the recited numerical range.

[0018] Unless otherwise specified, the term "from... to..." used in the specification to define a numerical range is intended to include the range equal to the recited endpoint values and the ranges between the recited endpoint values. For example, "a size range from a first numerical value to a second numerical value" means that the size range may include the first numerical value, the second numerical value, and any numerical value between the first numerical value and the second numerical value.

[0019] As used herein, non-limiting terms (such as "may", "might", "for example", or other similar terms) are not essential or are optional in any implementation, inclusion, addition, or presence.

[0020] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, terms defined as in a commonly used dictionary should be interpreted as having a meaning that coincides with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless explicitly 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. Next, an electrolysis process is performed to form a roughened layer on the copper foil. In the present invention, the electrolytic solution used for forming the roughened layer contains copper ions in the range of 0.1 g / L to 20 g / L (for example, 0.1 g / L, 1 g / L, 10 g / L, 20 g / L, or any numerical 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 (for example, 30 g / L, 50 g / L, 70 g / L, 90 g / L, 120 g / L, or any numerical value between 30 g / L and 120 g / L), and a complex compound in the range of 0.1 g / L to 10 g / L (for example, 0.1 g / L, 1 g / L, 3 g / L, 5 g / L, 7 g / L, 10 g / L, or any numerical 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 (for example, ten-point average roughness (Rz)) of the formed roughened layer is, for example, less than at least 1 μm (micrometer), and the peel resistance between the copper foil with the roughened layer formed thereon and the insulating resin (prepreg) is, for example, greater than at least 4 lb / in.

[0022] Furthermore, a complex compound is added to the electrolytic solution of the present invention. Therefore, compared with the current electrolytic copper foil that uses only copper sulfate (II) electrolytic solution, due to the complex reaction between the complex compound and copper, the divalent copper ions (Cu 2+ ) in the electrolytic solution are copper ions of other valences (monovalent copper ions (Cu +) etc.) are formed, thereby realizing an excellent nucleation and growth mechanism and optimizing the growth ability of three-dimensional copper nodules. For example, the coordination compounds of the present invention include benzotriazole (BTA)-based compounds (ionic liquids), propanesulfonic acid-based compounds, ethylenediaminetetraacetic acid (EDTA), or combinations thereof. The benzotriazole (BTA)-based compounds are selected from, for example, 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-based compounds are selected from, for example, 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 manufacturing the roughened copper foil of the present invention can be applied to circuit boards, but the present invention is not limited thereto.

[0024] In some embodiments, no other metal ions are further added to the electrolytic solution. For example, the electrolytic solution of the present invention does not contain metal ions such as iron (Fe) ions and cobalt (Co) ions. That is, the electrolytic solution contains ions of a single metal (copper ions), but the present invention is not limited thereto.

[0025] In some embodiments, in order to effectively obtain a desired copper nodule, the electrolysis process may be performed in multiple stages. 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, after growing the copper nodule in a desired range (such as dendritic growth, etc.) in the vertical direction by the first electrolysis process, the root portion of the copper nodule (the portion close to the copper foil) is thickened by the second electrolysis process, so that the adhesion between the copper nodule and the copper foil can be enhanced and peeling can be prevented. 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, but the present invention is not limited thereto.

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

[0027] In some embodiments, the thickness of the copper foil is 1.5 μm to 70 μm, but the present invention is not limited thereto.

[0028] In some embodiments, after performing the electrolysis process, a silane treatment step is further performed to additionally form a silane coupling layer on the surface of the roughened layer facing the copper foil. Thereby, the bonding strength between the roughened layer and other layers in subsequent processes can be further improved. 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 25°C to 60°C (e.g., 25°C, 35°C, 45°C, 55°C, 60°C, or any temperature between 25°C and 60°C), the current density of the electrolysis process is 1 A / dm 2 (ASD) to 120 A / dm 2 (e.g., 1 A / dm 2 , 10 A / dm 2 , 30 A / dm 2 , 50 A / dm 2 , 80 A / dm 2 , 120 A / dm 2 , or any current density between 1 A / dm 2 and 120 A / dm 2 . The time of the electrolysis process is 1 second to 45 seconds (e.g., 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 neither benzotriazole nor a benzotriazole-containing compound is 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] Using the electrolytic solution formulations of the examples and comparative examples shown in Table 1, roughened copper foils were each manufactured, and copper foil substrates of model number NPG170D were manufactured. 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 the metal substrate was measured according to the method described in IPC-TM-650-2.4.8.

[0035] The results of measuring the properties of the manufactured copper foil substrate are shown in Table 1. Comparing the examples and comparative examples in Table 1, it can be concluded that the peel resistance can be improved by adding the benzotriazole coordination compound.

[0036]

Table 1

[0037] In summary, in the present invention, the electrolytic solution used when 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 a coordination compound in the range of 0.1 g / L to 10 g / L. Therefore, the copper nodules constituting 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 is obvious to those skilled in the art that various modifications and deformations can be made to the disclosed embodiments without departing from the scope or spirit of the present invention. Considering the above, the present invention is intended to include modifications and deformations as long as they are within the scope of the claims and their equivalents.

Industrial Applicability

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

Claims

1. providing a copper foil; performing an electrolysis process to form a roughened layer on the copper foil, wherein the electrolytic solution 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 complex compound in the range of 0.1 g / L to 10 g / L, the forming; comprising; the complex compound is a benzotriazole-based compound; the electrolysis process includes a first electrolysis process and a second electrolysis process, and a first concentration of the copper ions used in the first electrolysis process is lower than a second concentration of the copper ions used in the second electrolysis process, a method for manufacturing a roughened copper foil.

2. The method for manufacturing a roughened copper foil according to Claim 1, wherein no other metal ions are further added to the electrolytic solution.

3. The method for manufacturing a roughened copper foil according to Claim 1, wherein the first concentration of the copper ions is 0.1 g / L to 10 g / L, and the second concentration of the copper ions is 1 g / L to 20 g / L.

4. The method for manufacturing a roughened copper foil according to Claim 1, further comprising performing a silane treatment step after performing the electrolysis process.

5. The method for manufacturing a roughened copper foil according to Claim 1, wherein direct current is used in the electrolysis process.

6. The method for manufacturing a roughened copper foil according to Claim 1, wherein the temperature of the electrolysis process is 25°C to 60°C.

7. The current density of the electrolysis process is 1 A / dm ２ ~120 A / dm ２ The method for manufacturing a roughened copper foil according to claim 1, wherein the current density is as defined above.

8. The method for manufacturing a roughened copper foil according to Claim 1, wherein the time of the electrolysis process is 1 second to 45 seconds.

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