TWI876541B - Manufacturing method of roughened copper foil - Google Patents

Abstract

The manufacturing method of the roughened copper foil includes the following steps. A copper foil is provided. An electrolytic process is performed to form a roughening layer on the copper foil. An electrolyte solution in the electrolysis process includes copper ions between 0.1g/L and 20g/L, sulfate ions between 30g/L and 120g/L, and coordination compound between 0.1g/L and 10g/L.

Description

Method for producing roughened copper foil

The present invention relates to a method for manufacturing a roughened copper foil.

With the development of fine lines on printed circuit boards (PCBs), the roughening layer on the surface of copper foil needs to become finer, but at the same time, the high adhesion between the copper foil and the insulating resin must be maintained. Therefore, how to produce a roughening layer with low roughness and high adhesion on the copper foil is a challenge.

The present invention provides a method for manufacturing a roughened copper foil, which can manufacture a roughened layer with low roughness and high adhesion on the copper foil.

The method for manufacturing a roughened copper foil of the present invention comprises the following steps: providing a copper foil; performing an electrolytic process to form a roughening treatment layer on the copper foil; the electrolyte in the electrolytic process comprises copper ions between 0.1 g/L and 20 g/L, sulfate ions between 30 g/L and 120 g/L, and complex between 0.1 g/L and 10 g/L.

In one embodiment of the present invention, the complex comprises benzotriazole compounds, propane sulfonic acid compounds, ethylenediaminetetraacetic acid or a combination thereof.

In one embodiment of the present invention, no other metal ions are further added to the above-mentioned electrolyte.

In one embodiment of the present invention, the electrolysis process includes a first electrolysis process and a second electrolysis process, and the first copper ion concentration used in the first electrolysis process is less than the second copper ion concentration used in the second electrolysis process.

In one embodiment of the present invention, the first copper ion concentration is between 0.1 g/L and 10 g/L, and the second copper ion concentration is between 1 g/L and 20 g/L.

In one embodiment of the present invention, performing the electrolysis process further includes performing a silanization process.

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

In one embodiment of the present invention, the temperature of the electrolysis process is between 25°C and 60°C.

In one embodiment of the present invention, the current density of the electrolysis process is between 1 A/dm ² and 120 A/dm ² .

In one embodiment of the present invention, the duration of the electrolysis process is between 1 second and 45 seconds.

Based on the above, the present invention improves the electrolyte used to form the roughening treatment layer, so that it includes copper ions between 0.1g/L and 20g/L, sulfate ions between 30g/L and 120g/L, and complexes between 0.1g/L and 10g/L. In this way, the copper nodules constituting the roughening treatment layer can be generated with an excellent nucleation and growth mechanism, so that a roughening treatment layer with low roughness and high adhesion can be manufactured on the copper foil.

In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below and described in detail with reference to the accompanying drawings.

In the following detailed description, for the purpose of illustration and not limitation, exemplary embodiments that disclose specific details are described to provide a thorough understanding of the various principles of the present invention. However, it will be apparent to one of ordinary skill in the art that, with the benefit of this disclosure, the present invention may be practiced in other embodiments that depart from the specific details disclosed herein. In addition, descriptions of well-known devices, methods, materials, and other specific details may be omitted to avoid obscuring the description of the various principles of the present invention.

In this article, the range expressed by "a value to another value" is a summary expression method to avoid listing all the values in the range one by one in the specification. Therefore, the description of a specific numerical range covers any numerical value in the numerical range and the smaller numerical range defined by any numerical value in the numerical range, just as the arbitrary numerical value and the smaller numerical range are written in the description text in the specification.

Unless otherwise specified, the term "between" used in this specification to define a range of numerical values is intended to cover ranges equal to the endpoint values and between the endpoint values. For example, a size range is between a first value and a second value, which means that the size range can cover the first value, the second value, and any value between the first value and the second value.

In this document, non-limiting terms (such as: may, could, for example, or other similar terms) refer to optional or necessary implementation, inclusion, addition, or presence.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly known or commonly understood in the art to which the present invention belongs. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with that in the relevant technical context and should not be interpreted in an idealized or overly formal sense unless expressly defined as such herein.

In this embodiment, the roughened copper foil is manufactured, for example, by the following steps. First, a copper foil is provided, and then an electrolytic process is performed to form a roughening treatment layer on the copper foil, wherein the present invention improves the electrolyte used to form the roughening treatment layer so that it includes copper ions between 0.1 g/L and 20 g/L (for example, 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 (SO ₄ ^2- ) and a complex between 0.1 g/L and 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), so that the copper nodules constituting the roughening layer can be generated with an excellent nucleation and growth mechanism, such as a fast nucleation rate, so that a roughening layer with low roughness and high adhesion (high surface area and high peel strength) can be manufactured on the copper foil. Here, the surface roughness (such as ten-point average roughness, Rz) of the roughened layer formed by the above method is, for example, at least less than 1 micrometer, and the peel strength between the copper foil on which the roughened layer is formed and the insulating resin (Preppreg) is, for example, at least greater than 4 lb/in.

Furthermore, the electrolyte of the present invention introduces a complex, so compared with the electrolytic copper foil currently using only copper sulfate electrolyte, the divalent copper ions (Cu ²⁺ ) in the electrolyte can form copper ions of other valences (such as monovalent copper ions (Cu ⁺ )) to achieve excellent nucleation and growth mechanisms and optimize the ability of copper tumors to form in three dimensions. For example, the complex of the present invention includes benzotriazole (BTA) compounds (ionic liquids), propane sulfonic acid compounds, ethylenediaminetetraacetic acid (EDTA) or a combination thereof, wherein the benzotriazole compound is selected from carboxybenzotriazole (CBTA), 1,2,3-benzotriazole, 1-chloro-1,2,3-benzotriazole, The propane sulfonic acid compound is selected from bis-(3-sulfopropyl)-disulfide disodium salt (SPS) and 3-mercapto-1-propanesulfonic acid (MPS), but the present invention is not limited thereto.

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

In some embodiments, no other metal ions are further added to the electrolyte. For example, the electrolyte of the present invention does not include metal ions such as iron (Fe) and cobalt (Co), that is, the electrolyte only includes a single metal ion (copper ion), but the present invention is not limited to this.

In some embodiments, the electrolysis process can be performed in multiple stages to more effectively obtain the desired copper nodules. For example, the electrolysis process includes a first electrolysis process and a second electrolysis process, and the first copper ion concentration used in the first electrolysis process is less than the second copper ion concentration used in the second electrolysis process. In this way, the copper nodules can be formed in the vertical direction by the first electrolysis process. After the copper nodule grows to a desired extent (such as tree-like growth), a second electrolytic process is used to thicken the base portion of the copper nodule (the portion close to the copper foil) to enhance the adhesion between the copper nodule and the copper foil and prevent it from peeling off. The first copper ion concentration is between 0.1/L and 10g/L, and the second copper ion concentration is between 1g/L and 20g/L, but the present invention is not limited thereto.

Here, the size and shape of the copper nodule can be determined according to actual design requirements, and the present invention is not limited thereto. As long as the surface roughness (Rz) of the roughened layer can be at least less than 1 micron, and the peel strength between the copper foil with the roughened layer formed thereon and the insulating resin (Preppreg) can be at least greater than 4 lb/in, it is within the protection scope of the present invention.

In some embodiments, the thickness of the copper foil is between 1.5 μm and 70 μm, but the present invention is not limited thereto.

In some embodiments, the electrolytic process is followed by a silanization process to form an additional silane coupling layer on the surface of the roughened layer opposite to the copper foil, thereby further improving the bonding strength between the roughened layer and other subsequent film layers. The silanization process can be performed using a silane coupling agent such as acryloxypropyltrimethoxysilane or the like, but the present invention is not limited thereto.

In some embodiments, the electrolysis process is operated under direct current, and 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 value between 25°C and 60°C), and the current density of the electrolysis process is between 1A/ ^dm2 (ASD) and 120A/ ^dm2 (e.g., 1A/ ^dm2 , 10A/ ^dm2 , 30A/ ^dm2 , 50A/ ^dm2 , 80A/ ^dm2 , 120A/ ^dm2, or any value between 1A/ ^dm2 and 120A/dm2). ² ), the time of the electrolysis process is between 1 second and 45 seconds (for example, 1 second, 10 seconds, 20 seconds, 30 seconds, 45 seconds or any value between 1 second and 45 seconds), but the present invention is not limited to this.

In some embodiments, when the copper trough of the present invention does not have benzotriazole added but has a benzotriazole compound added, its surface roughness (Rz) is between 1 micron and 1.5 microns, and the peeling force is greater than 4 lb/in. In comparison, when the copper trough does not have benzotriazole or a benzotriazole compound added, its surface roughness is between 1 micron and 1.5 microns, and the peeling force is less than 3 lb/in, but the present invention is not limited thereto.

The following embodiments and comparative examples are given to illustrate the effects of the present invention, but the scope of rights of the present invention is not limited to the scope of the embodiments.

The roughened copper foil made by the electrolyte formulations of the embodiments and comparative examples in Table 1 was used to make a copper foil substrate with model number NPG170D, and was evaluated according to the following method.

Surface roughness (Rz): Tested using laser or white light.

Peeling strength: According to the IPC-TM-650-2.4.8 test method, the peeling strength of the metal substrate is tested.

The relevant properties of the manufactured copper foil substrate were tested, and the results are shown in Table 1. By comparing the results of the embodiment and the comparative example in Table 1, the following conclusion can be drawn: adding benzotriazole complex can enhance the peeling force.

Table 1 Comparison Example 1 Embodiment 1 Copper ion concentration g/L 8 8 Sulfate ion concentration g/L 90 90 Complex concentration g/L 0 1.0 Temperature ℃ Room temperature (25℃) Room temperature (25℃) Current density ASD 65 65 Time 2 2 Surface roughness (Rz) um 1.2 1.2 Peel strength lb/in 2.5 4.2

In summary, the present invention improves the electrolyte used to form the roughening layer, so that it includes copper ions between 0.1 g/L and 20 g/L, sulfate ions between 30 g/L and 120 g/L, and complexes between 0.1 g/L and 10 g/L. In this way, the copper nodules constituting the roughening layer can be generated with an excellent nucleation and growth mechanism, so that a roughening layer with low roughness and high adhesion can be manufactured on the copper foil.

Although the present invention has been disclosed as above by the embodiments, they are not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be defined by the scope of the attached patent application.

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Claims (7)

A method for manufacturing a roughened copper foil comprises: providing a copper foil; and performing an electrolytic process to form a roughening treatment layer on the copper foil, wherein the electrolyte in the electrolytic process comprises copper ions between 0.1 g/L and 20 g/L, sulfate ions between 30 g/L and 120 g/L, and complexes between 0.1 g/L and 10 g/L, wherein the complexes comprise benzotriazole compounds, propane sulfonic acid compounds, ethylenediaminetetraacetic acid, or a combination thereof, and no other metal ions are further added to the electrolyte, wherein the electrolytic process comprises a first electrolytic process and a second electrolytic process, and the first copper ion concentration used in the first electrolytic process is less than the second copper ion concentration used in the second electrolytic process. A method for manufacturing a roughened copper foil as described in claim 1, wherein the first copper ion concentration is between 0.1 g/L and 10 g/L, and the second copper ion concentration is between 1 g/L and 20 g/L. The method for manufacturing roughened copper foil as described in claim 1 further includes performing a silanization process after performing the electrolysis process. A method for manufacturing a roughened copper foil as described in claim 1, wherein the electrolysis process uses direct current. The method for manufacturing roughened copper foil as described in claim 1, wherein the temperature of the electrolysis process is between 25°C and 60°C. A method for manufacturing a roughened copper foil as described in claim 1, wherein the current density of the electrolytic process is between 1A/ ^dm2 and 120A/ ^dm2 . The method for manufacturing a roughened copper foil as described in claim 1, wherein the duration of the electrolysis process is between 1 second and 45 seconds.