Copper foil and method for manufacturing the same

Abstract

This invention provides a method for manufacturing copper foil that enhances bonding strength (>2.3 lb / in) without affecting the roughness of the copper foil itself or its signal transmission performance, and also provides copper foil. [Solution] A method for manufacturing copper foil is provided, which includes providing raw foil and performing multiple roughening treatments and multiple fixation treatments on the raw foil. The plating solution used in the roughening treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound. The plating solution used in the fixation treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound.

Description

Technical Field

[0001] The present invention relates to a copper foil and a method for manufacturing the same, and particularly to a copper foil having a roughened surface and a method for manufacturing the same.

Background Art

[0002] In recent years, with the development of 5G communication, the demand for large-volume data transmission has been increasing day by day, and it is necessary to continuously improve the transmission speed of copper-clad laminate materials. The frequency range is increasing from less than 1 MHz to 1 GHz, 10 GHz, or higher. At high-frequency current density, the current mainly flows through the surface part of the conductor due to the "skin effect", and the depth of the current at 10 GHz is only 0.7 μm. Therefore, in the requirements of relatively high frequencies, the surface morphology of the copper foil is also developing towards lower roughness.

[0003] When the copper foil has a very low roughness (Rz < 0.3 μm), it can provide good signal transmission performance at high frequencies, but due to the low surface roughness, the physical bonding property in the laminate structure with the circuit board is poor (< 2 lb / in).

[0004] Therefore, in order to obtain a balance between good signal transmission performance and high bonding property, it is very important to develop a copper foil surface treatment technology that does not affect the roughness and signal transmission performance of the copper foil itself while increasing the bonding force (> 2.3 lb / in).

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention provides a copper foil and a method for manufacturing the same, and can endow the copper foil with a corresponding roughened surface by corresponding manufacturing process conditions and / or reaction reagents.

Means for Solving the Problems

[0007] The present invention provides a method for producing copper foil, comprising providing raw foil and performing multiple roughening treatments and multiple immobilization treatments on the raw foil. The plating solution used in the roughening treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound. The plating solution used in the immobilization treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound.

[0008] The copper foil of the present invention has a rough surface and a peel strength between it and the insulating material that is higher than 2.3 lb / in. [Effects of the Invention]

[0009] Based on the above, copper foil with a rough surface can be used in the manufacture of high-frequency transmission components because it has a peel strength from the insulating material that is higher than 2.3 lb / in and has low roughness. [Brief explanation of the drawing]

[0010] [Figure 1] This is a flowchart of a part of the method for manufacturing copper foil according to one embodiment of the present invention. [Figure 2] This is a partial diagram of equipment used to manufacture copper foil according to one embodiment of the present invention. [Figure 3] This is a partial diagram of equipment used to manufacture copper foil according to one embodiment of the present invention. [Figure 4A] This is a top view of a copper foil obtained using a scanning electron microscope (SEM) according to [Experimental Example 1] of the present invention. [Figure 4B] This is a scanning electron microscope top view of copper foil according to [Experimental Example 2] of the present invention. [Figure 4C] This is a scanning electron microscope top view of copper foil according to [Experimental Example 3] of the present invention. [Figure 4D] This is a scanning electron microscope top view of copper foil according to [Experimental Example 4] of the present invention. [Figure 5] This is a scanning electron microscope top view of a copper foil according to a comparative example of the present invention. [Modes for carrying out the invention]

[0011] Figure 1 is a flowchart of a part of the method for manufacturing copper foil according to one embodiment of the present invention. Figure 2 is a partial diagram of the equipment used to manufacture copper foil according to one embodiment of the present invention. Figure 3 is a partial diagram of the equipment used to manufacture copper foil according to one embodiment of the present invention.

[0012] Referring to Figure 1, the raw foil 81 is provided in step S91. In one embodiment, the raw foil 81 may be formed by an electrolytic method.

[0013] Referring to Figure 2, the step of forming the raw foil 81 by electrolysis may include providing a raw foil 81 manufacturing apparatus 100 that includes an electrolytic cell 110, an anode plate 120, a cathode roller 130, and a power supply unit 140. The power supply unit 140 is suitable for supplying, adjusting, and controlling electrical energy. For example, corresponding terminals of the power supply unit 140 are electrically connected to corresponding objects (e.g., the anode plate 120, the cathode roller 130) by corresponding conductors. Also, corresponding power control members of the power supply unit 140 may adjust the corresponding output power, output voltage, output current, and / or output frequency according to corresponding requirements.

[0014] The anode plate 120 is provided within the electrolytic cell 110 and is electrically connected to the high-voltage terminal (e.g., positive terminal) of the power supply unit 140. The anode plate 120 may be a single plate or multiple plates. The anode plate 120 corresponds to the cathode roller 130 by having corresponding arc-shaped portions. The anode plate 120 may include, for example, a dimensionally stable anode (DSA), which has high conductivity and corrosion resistance. A dimensionally stable anode is manufactured by coating a base material such as titanium plate or mesh steel plate with a suitable metal (e.g., ruthenium (Ru), platinum (Pt), titanium (Ti), iridium (Ir)) and / or its oxide.

[0015] The cathode roller 130 is provided in the electrolytic cell 110 corresponding to the anode plate 120, and is electrically connected to the low-voltage terminal (e.g., negative terminal or ground terminal) of the power supply unit 140. The cathode roller 130 has high conductivity and corrosion resistance, and is, for example, a titanium roller or a titanium-coated roller. The diameter of the cathode roller 130 may be, for example, 1.0 meter (m), 1.5 m, 2.2 m, or 2.7 m. The width of the cathode roller 130 may be 1100 mm to 1500 mm, for example, 1380 mm.

[0016] The electrolyte 71 may be injected into the electrolytic cell 110 in an appropriate manner. For example, the electrolyte 71 may be injected into the electrolytic cell 110 through a conduit 170. The electrolyte 71 injected into the electrolytic cell 110 immerses the anode plate 120 and a portion of the cathode roller 130. The electrolyte 71 may contain a broad-sense copper sulfate aqueous solution. A "broad-sense copper sulfate aqueous solution" means that the majority of its cations are copper ions, and the majority of its anions are sulfate ions, bisulfate ions, or a combination thereof. For example, the copper ion concentration in the electrolyte 71 may be about 50 grams / liter (g / L) to 90 g / L, and the sulfuric acid concentration in the electrolyte 71 (generally referring to the corresponding sulfate ion equivalent, for example, the sum of the concentrations of sulfuric acid, bisulfate ions, and sulfate ions, and so on) may be about 50 g / L to 120 g / L.

[0017] The electrolyte 71 may further contain appropriate additives, including, but are not limited to, halogen ions (e.g., chloride ions) in concentrations lower than about 1.5 ppm, glues (e.g., gelatin, polyethylene glycol (PEG), sodium polydithiodipropanesulfonate (SPS), or tertiary amine compounds), compounds having mercapto groups (e.g., sodium 3-mercapto-1-propanesulfonate (MPS)), high molecular weight polysaccharides (e.g., methylcellulose (MC), hydroxyethylcellulose (HEC)), or combinations thereof.

[0018] In one exemplary application method, after the electrolytic solution 71 immerses the anode plate 120 and partially immerses the cathode roller 130, the cathode roller 130 is rotated in an appropriate direction (for example, the clockwise direction illustrated in FIG. 2), and a corresponding DC voltage or DC current is output and / or adjusted by the power supply unit 140 to deposit copper ions in the electrolytic solution 71 on the surface of the cathode roller 130 to form a base foil 81.

[0019] Also, in the process of forming the base foil 81, the electrolytic solution 71 may be continuously injected into the electrolytic cell 110. Specifically, the electrolytic solution 71 may flow into the electrolytic cell 110 continuously or intermittently through the conduit 170, so that the copper ion concentration of the electrolytic solution 71 in the electrolytic cell 110 does not vary so as to affect the manufacturing process. Taking FIG. 2 as an example, the base foil 81 formed on the surface of the cathode roller 130 is peeled off from the surface of the cathode roller 130 for subsequent manufacturing processes (for example, illustrated in FIG. 3) or winding.

[0020] In one embodiment, on the premise that the concentration of the electrolytic solution 71 is regarded as a fixed value, the generated thickness of the base foil 81 may be adjusted by the intensity of the current, the rotation speed of the cathode roller 130, and / or the immersed amount of the cathode roller 130. In one embodiment, the thickness of the base foil 81 may be about 10 micrometers (μm) to 50 μm, for example, 18 μm, 35 μm. [[ID=】]

[0021] In an exemplary embodiment where the anode plate 120 includes a plurality of plate materials, each of the plurality of plate materials is individually or appropriately adjusted in current according to its corresponding different generation positions of the base foil 81 on the corresponding cathode roller 130 (for example, 75ASD (Ampere per square decimetre, A / dm ,

[0022] ) to 1000 ASD), so as to perform thickness compensation or adjustment for different generation positions. In this way, the uniformity of the thickness of the base foil 81 is improved, and the problems of wrinkles and warping are reduced.

[0022] The raw foil 81 has a first surface and a second surface opposite to the first surface. The first surface is the surface of the raw foil 81 that comes into contact with the cathode roller 130 during the electrolytic process, and / or the second surface is the surface that comes into contact with the electrolyte. The second surface is usually rougher than the first surface. That is, the first surface is relatively smooth, and the second surface is relatively rough. One side of the raw foil 81 that is located on the first surface is often called the drum side or shiny side. The other side of the raw foil 81 that is located on the second surface is often called the non-drum side or matte side. The raw foil 81 formed by the electrolytic method does not, or cannot, make the second surface excessively rough (for example, the roughness does not basically exceed 2 μm). In one embodiment, the ten-point average roughness (Rz) of the second surface does not exceed 2 μm, and is, for example, between 0.9 μm and 1.9 μm.

[0023] After the raw foil 81 is provided, a roughening treatment layer is formed on a predetermined surface of the raw foil 81, thereby forming a copper foil having nodular protrusions (also called copper tumors) on one surface. The aforementioned copper foil is often called electrolytic copper foil because it is mainly formed by electrolytic methods or electroplating.

[0024] In one possible method, raw foil 81 may be obtained directly by purchasing it.

[0025] Formation of the roughened layer involves performing at least one roughening treatment and at least one immobilization treatment. In one embodiment, the number of roughening treatments and / or immobilization treatments is multiple. In one embodiment, a single roughening treatment and a single immobilization treatment performed in sequence may be referred to as a single stage of the treatment cycle. In one embodiment, the aforementioned treatment cycle may consist of only one stage. In one embodiment, the aforementioned treatment cycle may consist of multiple stages.

[0026] While increasing the number of times the electroplating roughening and fixing processes are performed can increase the bonding strength between the roughened surface and the dielectric material (e.g., resin), it also increases the surface roughness of the copper foil, which may be unfavorable for applications in high-frequency signal transmission. Therefore, the number of times and the order of the roughening and fixing processes may be increased or decreased depending on the requirements of the actual manufacturing process.

[0027] As shown in Figure 1, in one embodiment, after step S91, the first roughening treatment (i.e., step S92), the first immobilization treatment (i.e., step S93), the second roughening treatment (i.e., step S94), and the second immobilization treatment (i.e., step S95) may be performed in order.

[0028] In one embodiment not shown, after step S100, a first roughening treatment (e.g., the same as or similar to step S92), a second roughening treatment (e.g., the same as or similar to step S99), a first immobilization treatment (e.g., the same as or similar to step S93), and a second immobilization treatment (e.g., the same as or similar to step S94) may be performed in order.

[0029] Referring to Figure 3, we will explain using the example of performing the first roughening treatment, the first fixing treatment, the second roughening treatment, and the second fixing treatment in that order.

[0030] As shown in Figure 3, the surface treatment apparatus 200 used in the first roughening treatment (i.e., step S92), the first immobilization treatment (i.e., step S93), the second roughening treatment (i.e., step S94), and the second immobilization treatment (i.e., step S95) includes, arranged on the production line, at least one roughening unit 220 (two shown in Figure 3), at least one immobilization unit 230 (two shown in Figure 3), a transfer or reversal unit 250, and selectively arranged cleaning tanks 240. The number of roughening units 220, immobilization units 230, cleaning tanks 240, and / or transfer or reversal units 250 is provided according to the actual requirements. For clarity, not all transfer or reversal units 250 are individually labeled in the figure. The transfer or reversal unit 250 may transfer the raw foil 81 to the roughening unit 220 and the immobilization unit 230 for processing according to a preset manufacturing process flow.

[0031] In the first roughening treatment, the roughening unit 220 used includes a roughening tank 221 used to contain the first plating solution 72 and an anode plate 222 provided inside the roughening tank 221. As shown in Figure 3, when the first roughening treatment is performed, the raw foil 81 is placed into the roughening tank 221 containing the first plating solution 72.

[0032] The first plating solution 72 may contain a broad-sense aqueous copper sulfate solution. For example, the copper ion concentration in the first plating solution 72 may be approximately 5 g / L to 25 g / L, and the sulfuric acid concentration in the electrolyte may be approximately 60 g / L to 150 g / L. In order to promote the formation of copper nodules, the first plating solution has a lower copper ion concentration and / or a higher sulfuric acid concentration compared to the electrolyte used in the production of the raw foil 81 described above.

[0033] In one embodiment, the copper ion concentration in the first plating solution 72 may be approximately 10 g / L to 20 g / L. In one embodiment, the copper ion concentration in the first plating solution 72 may be approximately 15 g / L. The aforementioned "approximately" may cover a range of ±5% of the concentration when expressing the concentration. For example, approximately 15 g / L may be 14.25 g / L to 15.75 g / L. Furthermore, when describing or indicating a specific single concentration in this specification (for example, numerical values ​​relating to experimental examples or comparative examples described later), "approximately" may be omitted to simplify the notation.

[0034] The first plating solution 72 may further contain appropriate additives, for example, other non-copper, non-alkali group metal, or non-alkaline earth group metal ions (e.g., tungsten ions, tin ions, iron ions, cobalt ions, nickel ions, or combinations thereof, without valency restrictions) (hereinafter referred to as other metal ions) in a concentration lower than approximately 50 ppm (e.g., 0.1 ppm to 50 ppm), and nitrogen-containing organic compounds (or corresponding ions) in a concentration lower than approximately 50 ppm (e.g., 0.1 ppm to 50 ppm). The aforementioned nitrogen-containing organic compounds are, for example, azole compounds.

[0035] In one embodiment, the concentration of the nitrogen-containing organic compound may be less than about 30 ppm (e.g., 0.1 ppm to 30 ppm). In one embodiment, the concentration of the nitrogen-containing organic compound may be less than about 20 ppm (e.g., 0.1 ppm to 20 ppm). In one embodiment, the concentration of the nitrogen-containing organic compound may be about 1 ppm to about 12 ppm. In one embodiment, the concentration of the nitrogen-containing organic compound may be about 3 ppm to about 10 ppm. In one embodiment, the concentration of the nitrogen-containing organic compound may be about 5 ppm to about 10 ppm. In one embodiment, the concentration of the nitrogen-containing organic compound may be about 7 ppm.

[0036] In one embodiment, the addition of a nitrogen-containing organic compound can impart relatively high surface polarity to the plated copper surface. In this way, the bonding strength between the plated copper and the polymer (for example, a polymer of atoms with lone pairs of electrons (e.g., oxygen, nitrogen, sulfur)) can be increased.

[0037] In one embodiment, the aforementioned azole compound may include a diazole compound, a triazole compound, a tetraazole compound, derivative compounds thereof, or a combination thereof. The aforementioned "derivative compound" may be the substitution of a hydrogen atom connected to a carbon atom of the azole ring with an electron-donating group, or the fusion / condensation of an azole ring and an aromatic ring. The aforementioned "electron-donating group" may be, for example, a dialkylamino group (-NRR'), an alkylamino group (-NHR), an amino group (-NH2), a hydroxyl group (-OH), or an alkoxy group (-OR), and is preferably a nitrogen-containing electron-donating group, and more preferably an amino group. The aforementioned "aromatic ring" may be, for example, a benzene ring or a naphthalene ring, and is preferably a benzene ring. The aforementioned "alkyl" may be, for example, an alkyl group with four or fewer carbon atoms (C4), such as methyl, ethyl, propyl, isopropyl, or butyl, with methyl or ethyl being preferred.

[0038] In one embodiment, the aforementioned electron-donating groups in nitrogen-containing organic compounds, and / or the fusion / condensation of azole rings and aromatic rings, can enhance the bonding strength between plated copper and polymers (e.g., polymers of atoms having lone pairs of electrons (e.g., oxygen, nitrogen, sulfur)).

[0039] In one embodiment, the tetrazole compound having an electron-donating group may include 5-aminotetrazole (CAS: 4418-61-5) and 1,5-diaminotetrazole (CAS: 2165-21-1).

[0040] In one embodiment, the diazole compound having an electron-donating group may include 2-amino-1,3,4-thiadiazole (CAS: 4005-51-0).

[0041] In one embodiment, the triazole compound having an electron-donating group may include 3,5-diamino-1,2,4-triazole (CAS: 1455-77-2).

[0042] In one embodiment, the aforementioned azole compound may include 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, benzotriazole (CAS: 95-14-7), or a combination thereof. In one embodiment, the aforementioned azole compound includes at least 2-amino-1,3,4-thiadiazole or 3,5-diamino-1,2,4-triazole. In one embodiment, the aforementioned azole compound includes at least 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, and benzotriazole.

[0043] In one embodiment, when the concentration of the azole compound used is less than 30 ppm, the use of 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, and benzotriazole may not result in a significant difference in bonding strength between plated copper and polymers (e.g., polymers of atoms with lone pairs of electrons (e.g., oxygen, nitrogen, sulfur)).

[0044] In one embodiment, the aforementioned azole compounds may include 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, benzotriazole (CAS: 95-14-7), or a combination thereof, and the concentration may be about 5 ppm to about 10 ppm. In this way, the size of the copper nodules can be matched, and the bonding strength between the plated copper and the polymer (e.g., a polymer of lone pairs of atoms (e.g., oxygen, nitrogen, sulfur) in particular) can be increased.

[0045] In one embodiment, the aforementioned azole compounds may include 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, benzotriazole (CAS: 95-14-7), or a combination thereof, and the concentration may be about 7 ppm. In this way, the size of the copper nodules can be further matched, and the bonding strength between the plated copper and the polymer (e.g., a polymer of lone pairs of atoms (e.g., oxygen, nitrogen, sulfur) in particular) can be further enhanced.

[0046] When the first roughening treatment is performed, a relatively high voltage (e.g., positive voltage) and a relatively low voltage (e.g., negative voltage or ground) are applied to the anode plate 222 and the raw foil 81 used for roughening, respectively, thereby reducing the copper ions in the first plating solution 72 and forming multiple nodular copper particles on the surface of the raw foil 81.

[0047] It should be noted that the first plating solution 72 used in the embodiments of the present invention has a special composition that can restrict the crystal growth direction of nodular copper particles. Furthermore, the concentrations of other metal ions and nitrogen-containing organic compounds do not exceed 100 ppm. If the concentration of other metal ions is excessively high, spherical copper nodules that are biased towards larger sizes may be formed, making it difficult to form copper nodules that are close to football-shaped. If the concentration of organic compounds is excessively high, the copper nodules may be biased towards larger sizes, or it may become difficult to control the entire manufacturing process (for example, uniformity may be poor).

[0048] Furthermore, when the first roughening treatment is performed, the copper concentration in the first plating solution 72 is relatively low (compared to the plating solution 71 used in the manufacture of the raw foil 81 mentioned above), so the copper atoms basically advance along the corresponding crystal direction (for example, the vertical direction). In other words, the nodular copper particles grow predominantly in a direction roughly perpendicular to the surface of the raw foil 81, and do not grow easily in a direction roughly parallel to the surface of the raw foil 81. For this reason, the degree of growth of the nodular copper particles in the horizontal direction is limited, which causes the nodular copper particles to have a rugby ball shape that stands upright on the surface of the raw foil 81.

[0049] Therefore, after the first roughening treatment, most of the nodular copper particles formed on the surface of the raw foil 81 have a horizontal size smaller than their vertical size, and the spacing between each adjacent pair of nodular copper particles becomes relatively wide.

[0050] In one embodiment, when the first roughening treatment is performed, the current density flowing through the roughened anode plate 222 is 10 ASD to 80 ASD, and nodular copper particles similar in shape to a rugby ball can be formed. In one embodiment, when the first roughening treatment is performed, the temperature of the first plating solution 72 is generally maintained at 20 to 40 degrees Celsius. In one embodiment, when the first roughening treatment is performed, the electroplating time is approximately 0.5 to 4 seconds.

[0051] In one embodiment, when the first roughening treatment is performed, the current density flowing through the roughened anode plate 222 is 10 ASD to 50 ASD. In one embodiment, when the first roughening treatment is performed, the current density flowing through the roughened anode plate 222 is 20 ASD to 40 ASD. In one embodiment, when the first roughening treatment is performed, the current density flowing through the roughened anode plate 222 is 25 ASD to 35 ASD. In one embodiment, when the first roughening treatment is performed, the current density flowing through the roughened anode plate 222 is approximately 33 ASD. During the electroplating process, the current density flowing may have slight fluctuations directly above the corresponding point due to the manufacturing process (e.g., movement of equipment, flow of liquid). The aforementioned "approximately" with respect to current density indicates that within a specific time range (e.g., 1 minute), the average current density may cover a range of ±10% of the current density; for example, approximately 33 ASD may be between 29.7 ASD and 36.3 ASD. Alternatively, within the minimum response / adjustment time range of the current control device (e.g., 0.1 seconds), the current density may cover a range of ±50% of the current density; for example, approximately 33 ASD may be between 16.5 ASD and 49.5 ASD. Furthermore, when describing or indicating a specific single current density in this specification (e.g., the values ​​in the experimental or comparative examples described later), the "approximately" may be omitted for brevity.

[0052] In one embodiment, the time for performing electroplating during the first roughening treatment is 1 to 3 seconds. In one embodiment, the time for performing electroplating during the first roughening treatment is approximately 2 seconds. The aforementioned "approximately" for the electroplating time indicates that it may include the minimum reaction / adjustment time range (e.g., 0.1 seconds) of the control member (e.g., power supply control member, roller control member), for example, approximately 2 seconds is 1.9 to 2.1 seconds. Also, when describing or indicating a specific single electroplating time in this specification (e.g., the numerical values ​​in the experimental examples or comparative examples described later), "approximately" may be omitted for brevity. In one embodiment, the electroplating time corresponds to the time during which the raw foil 81 is immersed in the plating solution and electroplated.

[0053] After the first roughening treatment is completed, the first fixing treatment is performed to form a copper protective layer covering the nodular copper particles, firmly fixing the nodular copper particles to the surface of the raw foil 81 and reducing the possibility of the nodular copper particles falling off (commonly known as powder peeling).

[0054] As shown in Figure 3, the first immobilization process is performed by the immobilization unit 230. The immobilization unit 230 includes an immobilization tank 231 used to contain the second plating solution 73, and an anode plate 232 provided in the immobilization tank 231.

[0055] In this embodiment, after the raw foil 81 completes the first roughening treatment in the roughening tank 221, it may first be transferred to the washing tank 240 by the transfer or direction changing unit 250 for washing, and then transferred to the immobilization tank 231 to perform the first immobilization treatment (but is not limited thereto).

[0056] When the first immobilization treatment is performed, a relatively high voltage (e.g., positive voltage) and a relatively low voltage (e.g., negative voltage or ground) are applied to the anode plate 232 and the raw foil 81 used for immobilization, respectively, which reduces the copper ions in the second plating solution 73 and forms a copper protective layer on the raw foil 81 that covers the nodular copper particles.

[0057] The second plating solution 73 may contain a broad-sense aqueous copper sulfate solution. For example, the copper ion concentration in the second plating solution 73 may be approximately 30 g / L to 80 g / L, and the sulfuric acid concentration in the electrolyte may be approximately 60 g / L to 150 g / L. Compared to the first plating solution 72 used to generate the copper nodules described above, the copper ion concentration of the second plating solution is higher, thereby promoting the formation of a copper protective layer.

[0058] In one embodiment, the copper ion concentration of the second plating solution 73 may be approximately 30 g / L to 100 g / L. In one embodiment, the copper ion concentration of the second plating solution 73 may be approximately 40 g / L to 80 g / L. In one embodiment, the copper ion concentration of the second plating solution 73 may be approximately 50 g / L to 70 g / L. In one embodiment, the copper ion concentration of the second plating solution 73 may be approximately 60 g / L.

[0059] The second plating solution 73 may further contain appropriate additives, for example, other non-copper, non-alkali group metal, or non-alkaline earth group metal ions (e.g., tungsten ions, tin ions, iron ions, cobalt ions, nickel ions, or combinations thereof; no valency limit) (hereinafter referred to as other metal ions) in a concentration lower than approximately 100 ppm (e.g., 0.1 ppm to 100 ppm), and nitrogen-containing organic compounds (or corresponding ions) in a concentration lower than approximately 50 ppm (e.g., 0.1 ppm to 50 ppm).

[0060] In one embodiment, the type, composition, and / or concentration of the nitrogen-containing organic compound used in the second plating solution 73 may be the same as or similar to the type, composition, and / or concentration of the nitrogen-containing organic compound used in the first plating solution 72.

[0061] One point to explain is that the height of the nodular copper particles formed in the first roughening treatment is not high. Although forming a relatively thick copper protective layer during the first immobilization treatment can reduce the possibility of powder delamination, it can also reduce the surface roughness of the copper foil, decreasing the surface area on which the copper foil can bond with the resin substrate and potentially lowering the peel strength. Therefore, when performing the first immobilization treatment, it is necessary to particularly adjust the current density to form a relatively thin copper protective layer with excellent uniform electrodeposition properties (throwing power). Based on this, powder delamination can be prevented, and the surface area on which the copper foil can bond with the resin substrate is not reduced.

[0062] In one embodiment, when the first immobilization treatment is performed, the current density flowing through the immobilized anode plate 232 is 0.1 ASD to 20 ASD, and a relatively dense copper protective layer can be formed. In one embodiment, when the first immobilization treatment is performed, the temperature of the second plating solution is generally maintained at 20 to 40 degrees Celsius. In one embodiment, when the first immobilization treatment is performed, the electroplating time is approximately 1 to 8 seconds.

[0063] In one embodiment, the current density for performing the first roughening treatment is higher than the current density for performing the first fixing treatment. In one embodiment, the current density for performing the first roughening treatment is 2 to 20 times the current density for performing the first fixing treatment. In one embodiment, the current density for performing the first roughening treatment is 5 to 15 times the current density for performing the first fixing treatment. In one embodiment, the current density for performing the first roughening treatment is approximately 10 times the current density for performing the first fixing treatment.

[0064] In one embodiment, the time required to perform the first immobilization treatment electroplating is longer than the time required to perform the first roughening treatment electroplating. In one embodiment, the time required to perform the first immobilization treatment electroplating is 1.5 to 5 times longer than the time required to perform the first roughening treatment electroplating. In one embodiment, the time required to perform the first immobilization treatment electroplating is 1.8 to 3 times longer than the time required to perform the first roughening treatment electroplating. In one embodiment, the time required to perform the first immobilization treatment electroplating is approximately twice the time required to perform the first roughening treatment electroplating.

[0065] In one embodiment, when the first immobilization process is performed, the current density flowing through the immobilized anode plate 232 is 1ASD to 5ASD. In one embodiment, when the first immobilization process is performed, the current density flowing through the immobilized anode plate 232 is 2ASD to 4ASD. In one embodiment, when the first immobilization process is performed, the current density flowing through the immobilized anode plate 232 is 2.5ASD to 3.5ASD. In one embodiment, when the first immobilization process is performed, the current density flowing through the immobilized anode plate 232 is approximately 3.3ASD.

[0066] In one embodiment, the time for performing the first immobilization electroplating treatment is 2 to 6 seconds. In another embodiment, the time for performing the first immobilization electroplating treatment is approximately 4 seconds.

[0067] In one embodiment, after performing a first roughening treatment and a first immobilization treatment, it is possible to form a copper foil having rugby ball-shaped protrusions, or protrusions close to the shape of a rugby ball, on its surface.

[0068] In one embodiment, the raw foil 81 that has undergone the first immobilization treatment is transferred from the immobilization tank 231 to the washing tank 240 by the transfer or reversal unit 250 and washed, thereby obtaining copper foil having a roughened surface (for example, copper foil including a roughened treatment layer).

[0069] In one embodiment, the above method can provide the formed copper foil surface with copper nodules of appropriate size and distribution. It also provides a relatively favorable bond between the copper foil and the insulating material (e.g., a prepreg, the material being, for example, epoxy or polyimide (PI)) (e.g., with a peel strength higher than 2.3 lb / in, which can be measured according to ISO 11339 or a similar standard).

[0070] In one embodiment, the peel strength between the copper foil and the insulating material, as measured according to ISO 11339 or a similar standard, is higher than 2.3 lb / in. In one embodiment, the peel strength between the copper foil and the insulating material, as measured according to ISO 11339 or a similar standard, is approximately 3.5 lb / in or higher. In one embodiment, the peel strength between the copper foil and the insulating material, as measured according to ISO 11339 or a similar standard, is approximately 3.6 lb / in or higher. In one embodiment, the peel strength between the copper foil and the insulating material, as measured according to ISO 11339 or a similar standard, is approximately 3.63 lb / in or higher.

[0071] In one embodiment, the copper foil is surface-measured in a top view, and the size of the copper nodules may be approximately 90 nanometers (nm) or larger. Or, approximately 97 nm or larger. Or, approximately 120 nm or larger. Or, approximately 125 nm or larger. Or, approximately 130 nm or larger. Or, approximately 136 nm or larger. Or, approximately 140 nm or larger. Or, approximately 147 nm or larger.

[0072] In one embodiment, the copper foil is surface-measured in a top view, and the size of the copper nodules may be approximately 400 nm or less. Or, approximately 388 nm or less. Or, approximately 310 nm or less. Or, approximately 305 nm or less. Or, approximately 260 nm or less. Or, approximately 256 nm or less. Or, approximately 230 nm or less. Or, approximately 222 nm or less.

[0073] In one embodiment, when the copper foil is surface-measured in a top view, the size range of the copper nodules (e.g., the distribution range of two standard deviations) may be approximately ±65% of the mean, or approximately ±60%, or approximately ±45%, or approximately ±39%, or approximately ±35%, or approximately ±34%, or approximately ±25%, or approximately ±20%. As an example of one embodiment, if the average size of the copper nodules is approximately 190.5 nm and the size range of the copper nodules is approximately ±34%, then the size range of the copper nodules is approximately 125 nm to approximately 256 nm. As an example of one embodiment, if the average size of the copper nodules is approximately 184.5 nm and the size range of the copper nodules is approximately ±20%, then the size range of the copper nodules is approximately 147 nm to approximately 222 nm.

[0074] In one embodiment, the above method can ensure that the ten-point average roughness (Rz) of the formed copper foil surface does not exceed 0.8 micrometers (μm). For example, it is about 0.7 μm or less. For example, 0.2 μm to 0.7 μm. For example, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, or a range between these two values. In this way, the copper foil can be used in the manufacture or application of high-frequency electronic products.

[0075] The copper foil formed by the above method can be used in the manufacture or application of high-frequency electronic products and can have good bonding properties and / or quality.

[0076] In one embodiment, if necessary, the raw foil 81 that has undergone the first immobilization treatment may be transferred from the immobilization tank 231 to the washing tank 240 by the transfer or reversal unit 250 for washing, and then transferred to the next roughening tank 221 for a second roughening treatment (but is not limited thereto).

[0077] In one embodiment, the parameters used in the second roughening treatment may be the same as or similar to the parameters used in the first roughening treatment (e.g., time, temperature, or current).

[0078] In one embodiment, the composition of the third plating solution 74 used in the second roughening treatment is generally the same as or similar to the composition of the first plating solution 72 used in the first roughening treatment.

[0079] In one embodiment, the current density used during the second roughening treatment may be higher or slightly higher than the current density used during the first roughening treatment. In this way, the multiple nodular copper particles already formed on the surface of the raw foil 81 can continue to grow. Furthermore, since the third plating solution 73 used during the second roughening treatment is the same as or similar to the first plating solution 72 used during the first roughening treatment, the growth direction of the nodular copper particles is again restricted to a direction generally perpendicular to the surface of the raw foil 81. As a result, the final bonding area between the copper foil and the resin substrate can be further increased.

[0080] Subsequently, if necessary, the raw foil 81 that has undergone the second roughening treatment may be transferred from the roughening tank 221 to another washing tank 240 by a transfer or reversal unit 250, and after washing, transferred to another immobilization tank 231 to perform a second immobilization treatment (but is not limited to this). By performing the second immobilization treatment, a further copper protective layer can be provided, thereby further reducing the possibility of powder peeling of nodular copper particles.

[0081] In one embodiment, the parameters used during the second immobilization process may be the same as or similar to the parameters used during the first immobilization process (e.g., time, temperature, or current).

[0082] In one embodiment, the composition of the fourth plating solution 75 used in the second immobilization treatment is generally the same as or similar to the composition of the second plating solution 73 used in the first immobilization treatment.

[0083] [Experimental Examples] and [Comparative Examples]

[0084] The present invention will be specifically described below with reference to experimental and comparative examples, but the present invention is not limited to the examples shown below.

[0085] <Manufacturing method>

[0086] Copper foils for the [Comparative Example] and each [Experimental Example] (i.e., [Experimental Example 1], [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4]) were formed using one embodiment described above. Specifically, the [Comparative Example] and each [Experimental Example] underwent the same first roughening treatment (e.g., step S92 described above) and first immobilization treatment (e.g., step S93 described above) in order using the same raw foil (e.g., raw foil 81 of the embodiment described above) and the same manufacturing apparatus (e.g., manufacturing apparatus 100 described above). The nitrogen-containing organic compounds used (if used) were 2-amino-1,3,4-thiadiazole, 3,5-diamino-1,2,4-triazole, benzotriazole, or a combination thereof. The differences between the [Comparative Example] and each [Experimental Example] are that nitrogen-containing organic compounds were not used in the plating solutions for the roughening and immobilization treatments ([Comparative Example]) and that there were differences in the concentration of nitrogen-containing organic compounds used in the plating solutions for the roughening and immobilization treatments ([Experimental Example 1], [Experimental Example 2], [Experimental Example 3], [Experimental Example 4]).

[0087] Table 1 shows the manufacturing parameters for the [Comparative Example] and each [Experimental Example], as well as the results for the copper foil with a roughened surface manufactured accordingly.

[0088] In Table 1, "Cu 2+ The unit of the concentration of copper ions in the corresponding plating solution, expressed as "g / L", is g / L. Taking [Experimental Example 3] as an example, the concentration of copper ions in the roughening treatment is approximately 15 g / L, and the concentration of copper ions in the immobilization treatment is approximately 60 g / L.

[0089] In Table 1, "SO4 2- The unit of the sulfuric acid concentration in the corresponding plating solution, expressed as "g / L", is g / L. Generally, this refers to the equivalent amount of sulfate ions, for example, the sum of the concentrations of sulfuric acid, bisulfate ions, and sulfate ions. Taking [Experimental Example 3] as an example, the corresponding sulfuric acid concentration (sum of the concentrations of sulfuric acid, bisulfate ions, and sulfate ions) in the roughening treatment and the immobilization treatment is approximately 90 g / L.

[0090] In Table 1, the unit of the concentration of nitrogen-containing organic compounds added to the corresponding plating solution, indicated as "nitrogen-containing addition," is ppm. Taking [Experimental Example 3] as an example, the concentration of nitrogen-containing organic compounds added in the roughening and immobilization treatments is approximately 7 ppm.

[0091] In Table 1, the unit of the plating current density flowing through the plate material (for example, the roughened anode plate 222 mentioned above), which is expressed as "current density," is ASD. Taking [Experimental Example 3] as an example, the corresponding plating current density in the roughening treatment is approximately 33 ASD, and the corresponding plating current density in the immobilization treatment is approximately 3.3 ASD.

[0092] In Table 1, the unit of the plating time expressed as "current time" is seconds. Taking [Experimental Example 3] as an example, the corresponding plating time in the roughening treatment is approximately 2 seconds, and the corresponding plating time in the fixation treatment is approximately 4 seconds.

[0093] In Table 1, "copper nodule size" refers to the median copper nodule size in nanometers, obtained or estimated by surface measurement on copper foil having a roughened surface as viewed from above (for example, as shown in Figures 4A to 4D and Figure 5), and its corresponding size range (expressed as a percentage). Taking [Experimental Example 3] as an example, the median size of the obtained or estimated copper nodule is approximately 184.5 nanometers, and its corresponding size range is ±20%. That is, approximately 184.5 nanometers ± approximately 37.5 nanometers. That is, approximately 147 nanometers to 222 nanometers.

[0094] In Table 1, the unit of peel strength between copper foil and insulating material (e.g., epoxy, polyimide (PI)), measured according to ISO 11339 or a similar standard, is lb / in. Taking Experimental Example 3 as an example, the peel strength between copper foil and insulating material is approximately 3.63 lb / in.

[0095] [Table 1]

[0096] Comparing the [Comparative Examples] in Table 1 with each [Experimental Example], the bonding between the copper foil and the insulating material in the [Experimental Example] is relatively high (i.e., the peeling force is relatively large).

[0097] Comparing [Experimental Example 1], [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4] in Table 1, we see that [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4] exhibit relatively superior consistency in the copper nodule size of the copper foil.

[0098] Comparing [Experimental Example 1], [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4] in Table 1, the bonding between the copper foil and the insulating material in [Experimental Example 1], [Experimental Example 2], and [Experimental Example 3] is even higher (i.e., the peeling force is even greater).

[0099] Comparing [Experimental Example 1], [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4] in Table 1, and comparing the bonding between the copper foil and the insulating material and the consistency of the copper nodule size of the copper foil, it can be seen that [Experimental Example 3] and [Experimental Example 4] show relatively high bonding between the copper foil and the insulating material, and relatively good consistency of the copper nodule size of the copper foil.

[0100] Comparing [Experimental Example 1], [Experimental Example 2], [Experimental Example 3], and [Experimental Example 4] in Table 1, and comparing the bonding between the copper foil and the insulating material and the consistency of the copper nodule size of the copper foil, it can be seen that [Experimental Example 3] shows an even higher level of bonding between the copper foil and the insulating material, and relatively superior consistency of the copper nodule size of the copper foil.

[0101] In summary, the copper foil having a rough surface according to the present invention has a peel strength from insulating material that is higher than 2.3 lb / in and has low roughness, making it suitable for use in the manufacture of high-frequency transmission components. [Industrial applicability]

[0102] The copper foil of the present invention and the quartz oscillator manufactured by the method for manufacturing the same, and / or the copper foil of the present invention can be used for the manufacture of electronic components such as communication products, in particular for the manufacture of high-frequency transmission components. [Explanation of symbols]

[0103] S91, S92, S93, S94, S95: Step 100: Raw foil production equipment 110: Electrolytic cell 120: Anode plate 130: Cathode Roller 140: Power supply unit (power adjustment or control device) 170: Conduit 71: Electrolyte 81: Raw foil 200:Surface treatment equipment 220: Roughening Unit 221: Roughening tank 222: Anode plate 230: Fixation unit 231: Immobilization tank 222: Anode plate 240: Cleaning tank 250: Transfer or reversal unit 72: First plating solution 73: Second plating solution 74: Third plating solution 75: Fourth plating solution

Claims

1. To provide raw gold leaf, This includes performing at least one roughening treatment and at least one fixing treatment on the raw foil. The plating solution used in the aforementioned roughening treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound, and A method for producing copper foil, wherein the plating solution used in the aforementioned immobilization treatment is an aqueous copper sulfate solution containing a nitrogen-containing organic compound.

2. The method for producing copper foil according to claim 1, wherein the nitrogen-containing organic compound contained in the plating solution used for the roughening treatment includes an azole compound.

3. The method for producing copper foil according to claim 2, wherein the concentration of nitrogen-containing organic compounds in the plating solution used for the roughening treatment is lower than 30 ppm.

4. The method for producing copper foil according to claim 1, wherein the nitrogen-containing organic compound contained in the plating solution used for the immobilization treatment includes an azole compound.

5. The method for producing copper foil according to claim 4, wherein the concentration of nitrogen-containing organic compounds in the plating solution used in the aforementioned immobilization treatment is lower than 30 ppm.

6. The method for manufacturing copper foil according to claim 1, wherein the corresponding current density in the roughening treatment is higher than the corresponding current density in the immobilization treatment.

7. The method for manufacturing copper foil according to claim 1, wherein the corresponding plating time in the roughening treatment is shorter than the corresponding plating time in the immobilization treatment.

8. The method for producing copper foil according to claim 1, wherein the copper ion concentration in the corresponding copper sulfate aqueous solution during the roughening treatment is lower than the copper ion concentration in the corresponding copper sulfate aqueous solution during the immobilization treatment.

9. The method for manufacturing copper foil according to claim 1, further comprising washing between the roughening treatment and the immobilization treatment.

10. Copper foil having a roughened surface and a peel strength between it and an insulating material greater than 2.3 lb / in.

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