Surface-treated copper foil and copper foil substrate

Abstract

A surface-treated copper foil (100) includes a treated surface (100A), wherein the solid volume of the treated surface (100A) is less than 1.90 μm3 / μm2. A copper foil substrate includes a carrier plate and a surface-treated copper foil (100) disposed on at least one surface of the carrier plate; wherein, the surface-treated copper foil (100) includes an electrolytic copper foil (110) and a surface treatment layer (112), the surface treatment layer (112) is disposed between the electrolytic copper foil (110) and the carrier plate, the surface treatment layer (112) includes a treated surface (100A) facing the carrier plate, and the solid volume of the treated surface (100A) is less than 1.90 μm3 / μm2. By controlling the solid volume of the treated surface (100A) of the surface-treated copper foil (100) to be less than 1.90 μm3 / μm2, when the surface-treated copper foil (100) is subsequently laminated to the carrier plate, a lower degree of signal transmission loss can be maintained.

Description

Technical Field

[0001] The present invention relates to copper foils, and particularly to a surface-treated copper foil and a copper foil substrate. Background Art

[0002] With the trend of electronic products gradually becoming thinner and lighter and transmitting high-frequency signals, the demand for copper foils and copper foil substrates is also increasing day by day. Generally, the copper conductive lines of a copper foil substrate are carried by an insulating carrier, and through the layout design of the conductive lines, the electrical signals can be transmitted along a predetermined path to a predetermined area. In addition, for a copper foil substrate used for transmitting high-frequency electrical signals (such as higher than 10 GHz), the conductive lines of the copper foil substrate must also be further optimized to reduce the signal transmission loss caused by the skin effect. The so-called skin effect refers to that as the frequency of the electrical signal increases, the transmission path of the current will be more concentrated on the surface of the wire, especially more concentrated on the surface of the wire adjacent to the carrier. In order to reduce the signal transmission loss caused by the skin effect, the existing method is to flatten the surface of the wire adjacent to the carrier in the copper foil substrate as much as possible. In addition, in order to maintain the adhesion between the wire surface and the carrier at the same time, a reverse-treated foil (RTF) can also be used to make the wire. Among them, the reverse-treated foil refers to a copper foil whose drum side is subjected to a roughening treatment process.

[0003] However, even though the above method can effectively reduce the signal transmission loss generated by the copper foil substrate, there are still technical defects to be overcome. For example, since the surface of the wire facing the carrier is relatively flat, the adhesion between the wire and the carrier is usually low. In such a case, even if a reverse-treated foil is used to make the wire, the wire in the copper foil substrate is still easily peeled off from the surface of the carrier, resulting in the inability of the electrical signal to be transmitted along the predetermined path to the predetermined area. Therefore, it is still necessary to provide a surface-treated copper foil and a copper foil substrate to solve this defect existing in the prior art. Summary of the Invention

[0004] The main object of the present invention is to provide a surface-treated copper foil and a copper foil substrate to solve the problems existing in the above prior art.

[0005] According to an embodiment of the present invention, a surface-treated copper foil is provided, and the surface-treated copper foil includes a treated surface, wherein the solid volume of the treated surface is less than 190 μm 3 / μm 2 .

[0006] Optionally, according to another embodiment of the present invention, a surface-treated copper foil is provided. The surface-treated copper foil includes an electrolytic copper foil and a surface treatment layer provided on the roller surface of the electrolytic copper foil. Among them, the surface treatment layer includes a roughened layer, and the outside of the surface treatment layer is the treatment surface of the surface-treated copper foil. The solid volume of the treatment surface is less than 1.90 μm 3 / μm 2 。

[0007] According to still another embodiment of the present invention, a copper foil substrate is provided. The copper foil substrate includes a carrier board and at least one surface-treated copper foil provided on the surface of the carrier board; among them, the surface-treated copper foil includes an electrolytic copper foil and a surface treatment layer, the surface treatment layer is provided between the electrolytic copper foil and the carrier board, the surface treatment layer includes a treatment surface facing the carrier board, and the solid volume of this treatment surface is less than 1.90 μm 3 / μm 2 。

[0008] According to the above embodiment, by controlling the solid volume of the treatment surface of the surface-treated copper foil (material volume, denoted as Vm, which is an international standard for measuring surface roughness, and its unit μm 3 / μm 2 refers to the volume of the surface with a unit area of 1 μm 2 to be less than 1.90 μm 3 / μm 2 , when the surface-treated copper foil is subsequently laminated to the carrier board, a lower signal transmission loss level can be maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a schematic cross-sectional view of a surface-treated copper foil shown according to an embodiment of the present invention;

[0010] Figure 2 is a graph showing the relationship between the surface height and the loading rate of the surface-treated copper foil according to an embodiment of the present invention;

[0011] Figure 3 is a schematic diagram of a strip-line shown according to an embodiment of the present invention.

[0012] Description of the reference numerals:

[0013] 100 Surface-treated copper foil

[0014] 100A Treatment surface

[0015] 110 Electrolytic copper foil

[0016] 110A First surface

[0017] 110B Second surface

[0018] 112 Surface treatment layer

[0019] 114 Roughened layer

[0020] 116 Passivation layer

[0021] 118 Rust prevention layer

[0022] 120 Coupling layer

[0023] 204 Solid volume

[0024] 204A Solid volume of the peak part

[0025] 204B Solid volume of the core part

[0026] 300 Stripline

[0027] 302 Conducting wire

[0028] 304 Resin carrier board

[0029] 306-1 Ground electrode

[0030] 306-2 Ground electrode

[0031] t Thickness

[0032] w Width Detailed implementation manners

[0033] The present invention will be further described below with reference to the accompanying drawings and preferred implementation manners.

[0034] The following are the detailed implementation manners of the surface-treated copper foil, copper foil substrate, and printed circuit board, so that those of ordinary skill in the art can implement the present invention accordingly. These detailed implementation manners can refer to the corresponding drawings. Although the embodiments of the present invention are disclosed below, they are not intended to limit the present invention. Any person of ordinary skill in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Among them, the methods used in each embodiment and experimental example are conventional methods unless otherwise specified.

[0035] Regarding the spatial-related descriptive terms mentioned in the present invention, terms such as "on" and "above" should be interpreted in the broadest manner in the present invention, such that terms like "on" and "above" not only refer to being directly on something, but also can include being on something in the case where there are intermediate features or an intermediate layer between the two, and "on" or "above" not only refer to being above or over something, but also can include being in a state of being above or over something (i.e., directly on something) in the case where there are no intermediate features or an intermediate layer between the two.

[0036] In addition, unless otherwise indicated hereinafter, the numerical parameters described in the present invention are approximate numbers, which can vary as needed, or at least should be interpreted according to the significant digit numbers disclosed and using the usual rounding methods for each numerical parameter. In the present invention, a range can be expressed as from one endpoint to the other endpoint, or between two endpoints. Unless otherwise specifically stated, all ranges in the present invention include the endpoints.

[0037] It should be noted that without departing from the spirit of the present invention, the technical features in the different embodiments described hereinafter can be replaced, recombined, and mixed with each other to form other embodiments.

[0038] Figure 1 It is a schematic cross-sectional view of a surface-treated copper foil shown according to an embodiment of the present invention. As Figure 1 shown, the surface-treated copper foil 100 at least includes an electrolytic copper foil 110. The thickness of the electrolytic copper foil 110 is generally greater than or equal to 6 μm, for example, between 7 and 250 μm, or between 9 and 210 μm. The electrolytic copper foil 110 can be made by electrodeposition (also known as electrolysis, electro-deposition, electroplating). The electrolytic copper foil 110 has two oppositely arranged first surfaces 110A and second surfaces 110B. According to an embodiment of the present invention, the drum side of the electrolytic copper foil can correspond to the first surface 110A of the electrolytic copper foil 110, and the deposited side of the electrolytic copper foil can correspond to the second surface 110B of the electrolytic copper foil 110, but it is not limited thereto.

[0039] According to an embodiment of the present invention, other layers may be respectively provided on the first surface 110A and the second surface 110B of the electrolytic copper foil 110. For example, a surface treatment layer 112 may be provided on the first surface 110A. According to other embodiments of the present invention, the first surface 110A and the second surface 110B of the electrolytic copper foil 110 may be further provided with other single-layer or multi-layer structures, or the surface treatment layer 112 on the first surface 110A may be replaced by other single-layer or multi-layer structures, or no layers may be provided on the first surface 110A and the second surface 110B, but not limited thereto. Therefore, in these embodiments, the treated surface 100A of the surface-treated copper foil 100 and the surface on the opposite side of the treated surface 100A may correspond to the outer sides of other single-layer or multi-layer structures, or may correspond to the first surface 110A and the second surface 110B of the electrolytic copper foil 110, but not limited thereto.

[0040] The aforementioned surface treatment layer 112 may be a single layer or a stack layer including multiple sub-layers. For the case where the surface treatment layer 112 is a stack layer, each sub-layer may be selected from the group consisting of a roughening layer 114, a passivation layer 116, an anti-rust layer 118, and a coupling layer 120. For the surface-treated copper foil 100 provided with the surface treatment layer 112, the outer side of the surface treatment layer 112 may be regarded as the treated surface 100A of the surface-treated copper foil 100, and this treated surface 100A will contact the carrier plate through the subsequent process of laminating the surface-treated copper foil 100 to the carrier plate. According to an embodiment of the present invention, the surface treatment layer 112 is provided on the roller surface of the electrolytic copper foil 110 and includes a roughening layer 114. According to an embodiment of the present invention, the surface treatment layer 112 is provided on the roller surface of the electrolytic copper foil 110 and includes a roughening layer 114 and a passivation layer 116. According to an embodiment of the present invention, the surface treatment layer 112 is provided on the roller surface of the electrolytic copper foil 110 and includes a roughening layer 114, a passivation layer 116, and an anti-rust layer 118.

[0041] The roughening layer includes roughening particles (nodule). Among them, the roughening particles can be used to enhance the surface roughness of the electrolytic copper foil, and the roughening particles can be copper roughening particles or copper alloy roughening particles. According to an embodiment of the present invention, a covering layer may be additionally provided to be provided on the roughening layer and contain copper. The covering layer can be used to prevent the roughening particles from peeling off the electrolytic copper foil.

[0042] The passivation layer can have the same or different compositions, such as a metal layer or a metal alloy layer. Among them, the aforementioned metal layer can be selected from, but not limited to, nickel, zinc, chromium, cobalt, molybdenum, iron, tin, and vanadium. For example, it can be a nickel layer, a nickel-zinc alloy layer, a zinc layer, a zinc-tin alloy layer, or a chromium layer. In addition, the metal layer and the metal alloy layer can be a single-layer or multi-layer structure, such as single layers containing zinc and nickel stacked on each other. When it is a multi-layer structure, the stacking order between the layers can be adjusted according to needs without any specific limitation. For example, the zinc-containing layer can be stacked on the nickel-containing layer, or the nickel-containing layer can be stacked on the zinc-containing layer.

[0043] The anti-rust layer is a coating layer applied to the outside of the metal, which can be used to prevent the metal from deteriorating due to corrosion, etc. The anti-rust layer contains a metal or an organic compound. When the anti-rust layer contains a metal, the aforementioned metal can be chromium or a chromium alloy, and the chromium alloy can further contain one selected from nickel, zinc, cobalt, molybdenum, vanadium, and their combinations. When the anti-rust layer contains an organic compound, the aforementioned organic compound can be at least one selected from the group consisting of triazole, thiazole, imidazole, and their derivatives.

[0044] The coupling layer can be made of silane, which can be selected from, but not limited to, 3-aminopropyltriethoxysilane (APTES), N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, (3-glycidyloxypropyl)triethoxysilane, (8-glycidyloxyoctyl)trimethoxysilane, methacryloylpropyltriethoxysilane, methacryloyloctyltrimethoxysilane, methacryloylpropyltrimethoxysilane, (3-mercaptopropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, which is used to enhance the adhesion between the electrolytic copper foil and other materials (such as a carrier board).

[0045] According to an embodiment of the present invention, since the total thickness of the passivation layer, the rust prevention layer, and the coupling layer in the surface treatment layer is much smaller than the thickness of the roughening layer, the surface morphology of the treated surface of the surface-treated copper foil is mainly affected by the roughening layer.

[0046] By controlling the surface characteristics of the treated surface of the surface-treated copper foil, a lower transmission loss can be achieved at high frequencies. For example, the solid volume (Vm) of the treated surface of the surface-treated copper foil can be controlled so that the prepared copper foil substrate has good transmission characteristics.

[0047] The above-mentioned solid volume (Vm) is as Figure 2 shown, and it is obtained according to the standard method ISO 25178-2:2012. Figure 2 It is a relationship diagram between the surface height and the loading ratio of the surface-treated copper foil according to an embodiment of the present invention. Among them, the calculation of the solid volume (Vm) 204 is to integrate the volume of the solid enclosed by the curve below and above the horizontal cutting line, where the horizontal cutting line is the height corresponding to the curve at the loading ratio (material ratio, mr) of P2. That is, the solid volume (Vm) 204 is the range enclosed by the curve below and above the horizontal cutting line at the height corresponding to the loading ratio (mr) of P2 (80%) within the range of the loading ratio (mr) from 0% to the loading ratio (mr) of P2 (80%). In addition, the solid volume (Vm) 204 is obtained by summing the peak part solid volume (Vmp) 204A and the core part solid volume (Vmc) 204B. Further, the calculation of the peak part solid volume (Vmp) 204A is to integrate the volume of the solid enclosed by the curve below and above another horizontal cutting line, where the position of the other horizontal cutting line is the height corresponding to the curve at the loading ratio (mr) of P1; and the calculation of the core part solid volume (Vmc) 204B is to integrate the volume of the solid enclosed by the curve and the two horizontal cutting lines, where the positions of the two horizontal cutting lines are the heights corresponding to the curve at the loading ratios (mr) of P1 and P2 respectively. It should be noted that unless otherwise specified, the solid volume (Vm) referred to in the present invention is the value calculated within the range of the loading ratio (mr) from 0% to 80%.

[0048] In a specific embodiment of the present invention, the solid volume (Vm) of the treated surface of the surface-treated copper foil is less than 1.90 μm 3 / μm 2 That is, 0 to 1.90 μm 3 / μm 2 Preferably, it is 0.11 to 1.86 μm 3 / μrn 2 More preferably, it is 0.25 to 0.85 μm 3 / μm 2When the physical volume (Vm) is within the foregoing range, for the corresponding copper foil substrate and printed circuit board, signal transmission loss at high frequencies can be reduced.

[0049] In another specific embodiment of the present invention, the arithmetic mean height (Sa) of the treated surface of the surface-treated copper foil can be 0.10 to 2.02 μm, preferably 0.19 to 2.00 μm, and more preferably 0.49 to 1.53 μm. When the arithmetic mean height (Sa) is within the foregoing range, the peel strength between the surface-treated copper foil and the contacting carrier plate can be increased.

[0050] In another specific embodiment of the present invention, high reliability can be achieved by controlling the chemical composition of the surface-treated copper foil, and reliability tests are used to evaluate the ability of the copper foil substrate and circuit board prepared from the surface-treated copper foil to withstand high temperature, high pressure, and high humidity conditions. This test helps to evaluate the heat resistance of a resin-sealed device such as a circuit board during reflow soldering, and this test can be used as an accelerated test to predict whether resin cracks caused by heating will form during the reflow step of the circuit board manufacturing process, and at the same time, it can evaluate the expected performance of the manufactured copper foil substrate or circuit board during storage and transportation.

[0051] In another specific embodiment of the present invention, the oxygen content of the surface-treated copper foil is less than 469 ppm, preferably less than 349 ppm, and more preferably 53 to 348 ppm. In another specific embodiment of the present invention, the hydrogen content of the surface-treated copper foil is less than 40 ppm, preferably less than 30 ppm, and more preferably 5 to 29 ppm. When the oxygen content or hydrogen content is within the foregoing range, the copper foil substrate and circuit board prepared using the surface-treated copper foil can have high reliability.

[0052] The copper foil substrate includes at least a surface-treated copper foil and a carrier plate. Among them, the surface-treated copper foil includes an electrolytic copper foil and a surface treatment layer, and the surface treatment layer is disposed between the electrolytic copper foil and the carrier plate. Among them, the treated surface of the surface-treated copper foil faces and directly contacts the carrier plate.

[0053] Among them, the above-mentioned carrier board can be made of bakelite, polymer board or fiberglass board, but is not limited thereto. The polymer components of the polymer board can be, for example: epoxy resin, phenolic resins, polyester resins, polyimide resins, acrylics, formaldehyde resins, bismaleimidetriazine resins (also known as BT resins), cyanate ester resin, fluoropolymers, poly ether sulfone, cellulosic thermoplastics, polycarbonate, polyolefins, polypropylene, polysulfide, polyurethane, polyimide, Liquid Crystal Polymer (LCP), polyphenyleneoxide (PPO). The above fiberglass board can be a prepreg formed by immersing fiberglass non-woven materials in the aforementioned polymer (such as: epoxy resin).

[0054] In the following, the manufacturing methods of the surface-treated copper foil and the copper foil substrate will be further described exemplarily.

[0055] (1) Step A: Provide an electrolytic copper foil. An electrolytic copper foil can be formed by an electrolytic deposition method using a foil making machine. The foil making machine at least includes a metal cathode roller, an insoluble metal anode plate, and an electrolyte feeding pipe. Among them, the metal cathode roller is a rotatable roller, and the metal anode plate can be detachably fixed to the lower half of the metal cathode roller to surround the lower half of the metal cathode roller. The feeding pipe can be fixed directly below the metal cathode roller and is located between the two metal anode plates. The length direction of the feeding pipe is parallel to the axial direction of the metal cathode roller, and a plurality of openings are provided in the length direction of the feeding pipe so that the electrolyte can be dispersed substantially uniformly along the length of the cathode roller. The shortest distance between the metal cathode roller and the metal anode plate and the distance between the center of the feeding pipe and the metal anode plate are controllable.

[0056] During the electrolytic deposition process, the electrolyte inlet pipe continuously supplies electrolyte between the metal cathode roller and the metal anode plate. By applying an electric current between the metal cathode roller and the metal anode plate, copper can be electrolytically deposited on the metal cathode roller to form an electrolytic copper foil. In addition, by continuously rotating the metal cathode roller and peeling the electrolytic copper foil from one side of the metal cathode roller, a continuous electrolytic copper foil can be produced. Among them, the surface of the electrolytic copper foil facing the metal cathode roller can be called the roller surface, and the surface of the electrolytic copper foil away from the metal cathode roller can be called the deposition surface.

[0057] For electrolytic copper foil, the example range of its manufacturing parameters is as follows:

[0058] <1.1 Composition and Electrolysis Conditions of Copper Sulfate Electrolyte>

[0059] Copper sulfate (CuSO4·5H2O): 320 g / L

[0060] Sulfuric acid: 100 g / L

[0061] Chloride ion (from hydrochloric acid, RCI Labscan Ltd.): 20 mg / L

[0062] Gelatin (DV, Nippi, Inc.): 0.35 mg / L

[0063] Liquid temperature: 50 °C

[0064] Current density: 70 A / dm 2

[0065] Copper foil thickness: 35 μm

[0066] <1.2 Distance between Components in the Foil Making Machine>

[0067] The shortest distance between the metal cathode roller and the metal anode plate: 6 to 12 mm

[0068] The distance between the center of the inlet pipe and the metal anode plate: 15 to 25 mm

[0069] (2) Step B. In this step B, a surface cleaning process is performed on the above copper foil to ensure that the surface of the copper foil does not have contaminants (such as oil stains, oxides). The example range of its process parameters is as follows:

[0070] <2.1 Composition and Cleaning Conditions of the Cleaning Solution>

[0071] Copper sulfate: 130 g / L

[0072] Sulfuric acid: 50 g / L

[0073] Liquid temperature: 27 °C

[0074] Immersion time: 30 seconds

[0075] (3) Step C: In this step C, a roughened layer is formed on the roller surface of the above-mentioned copper foil. The example of the process parameter range is as follows:

[0076] <31 Parameters for making the roughened layer>

[0077] Copper sulfate (CuSO4·5H2O): 70 g / L

[0078] Sulfuric acid: 100 g / L

[0079] Sodium molybdate (Na2MoO4): 50 to 400 mg / L

[0080] Tin sulfate (SnSO4): 1000 to 5000 mg / L

[0081] Saccharin (1,1-dioxo-1,2-benzothiazol-3-one, saccharin, Sigma-Aldrich Company): 10 mg / L

[0082] Liquid temperature: 25 °C

[0083] Current density: 10 A / dm 2

[0084] Time: 10 seconds

[0085] (4) Step D: In this step D, a covering layer is formed on the above-mentioned roughened layer. The example of the process parameter range is as follows:

[0086] <41 Parameters for making the covering layer>

[0087] Copper sulfate (CuSO4·5H2O): 320 g / L

[0088] Sulfuric acid: 100 g / L

[0089] Liquid temperature: 40 °C

[0090] Current density: 15 A / dm 2

[0091] Time: 10 seconds

[0092] (5) Step E: In this step E, a nickel-containing layer is formed on the above-mentioned covering layer. The example of the process parameter range is as follows:

[0093] <5.1 Electrolyte composition and electrolysis conditions of the nickel-containing layer>

[0094] Nickel sulfate (NiSO4): 188 g / L

[0095] Boric acid (H3BO3): 32 g / L

[0096] Hypophosphorous acid (H3PO2): 0 to 5 g / L

[0097] Liquid temperature: 20 °C

[0098] Solution pH: 3.5

[0099] Current density: 0.5 to 0.9 A / dm 2

[0100] Time: 3 seconds

[0101] (6) Step F. This step F is to form a zinc-containing layer on the deposition surfaces of the above nickel-containing layer and the above copper foil. The example of the process parameter range is as follows:

[0102] <61 Electrolyte composition and electrolysis conditions of the zinc-containing layer>

[0103] Zinc sulfate (ZnSO4): 11 g / L

[0104] Ammonium metavanadate (NH4VO3): 0.25 g / L

[0105] Liquid temperature: 15 °C

[0106] Solution pH: 13

[0107] Current density: 0.3 to 0.7 A / dm 2

[0108] Time: 2 seconds

[0109] (7) Step G. This step G is to form a chromium-containing layer on the above two zinc-containing layers. The example of the process parameter range is as follows:

[0110] <7.1 Electrolyte composition and electrolysis conditions of the chromium-containing layer>

[0111] Chromic acid: 5 g / L

[0112] Liquid temperature: 35 °C

[0113] Solution pH: 12.5

[0114] Current density: 10 A / dm 2

[0115] Time: 5 seconds

[0116] (8) Step H. This step H is to form a coupling layer on the chromium-containing layer on the roller surface of the above copper foil. It is to spray an aqueous solution containing a silane coupling agent onto the chromium-containing layer on the roller surface of the copper foil to form a coupling layer. The example of the process parameter range is as follows:

[0117] <8.1 Preparation conditions of the coupling layer>

[0118] Silane coupling agent: (3-aminopropyl)triethoxysilane

[0119] Concentration of silane coupling agent in aqueous solution: 0.25 wt.%

[0120] Spraying time: 10 seconds

[0121] (9) Step I. In this step I, the surface-treated copper foil formed through the above steps is laminated to a carrier plate to form a copper foil substrate. According to an embodiment of the present invention, a copper foil substrate can be formed by thermally laminating the Figure 1 shown surface-treated copper foil 100 to a carrier plate.

[0122] In order for those of ordinary skill in the art to implement the present invention, the following will further describe in detail each specific embodiment of the present invention to specifically illustrate the surface-treated copper foil and copper foil substrate of the present invention. It should be noted that the following embodiments are only exemplary and should not be construed as limiting the present invention. That is, without exceeding the protection scope of the present invention, the materials, the amounts and ratios of the materials, and the processing procedures used in each embodiment can be appropriately changed.

[0123] Example 1

[0124] Example 1 is a surface-treated copper foil, and its manufacturing process corresponds to steps A to H in the above manufacturing method. The manufacturing parameters that are different between Example 1 and the above manufacturing method are recorded in Table 1 below.

[0125] Examples 2 - 17

[0126] The manufacturing procedures of Examples 2 - 17 are substantially the same as those of Example 1, and the manufacturing parameters that are different between them are recorded in Table 1.

[0127] Table 1

[0128]

[0129] The following further describes the test results of each of the above Examples 1 - 17, such as: <hydrogen content>, <oxygen content>, <arithmetic mean height (Sa)>, <actual volume (Vm)>, <reliability>, <peel strength>, and <signal transmission loss>.

[0130] <hydrogen content> and <oxygen content>

[0131] An oxygen / hydrogen / nitrogen analyzer (EMGA-930, Horiba Ltd.) equipped with a non-dispersive infrared (NDIR) detector is used to detect the oxygen content and hydrogen content of the surface-treated copper foil.

[0132] <arithmetic mean height (Sa)>

[0133] According to the standard ISO 25178-2:2012, the arithmetic mean height (Sa) of the treated surface of the surface-treated copper foil was measured by surface texture analysis using a laser microscope (LEXT OLS5000-SAF, Olympus). The test results are shown in Table 2 described below. The specific measurement conditions are as follows:

[0134] Light source wavelength: 405 nm

[0135] Objective lens magnification: 100x objective lens (MPLAPON-100x LEXT, Olympus)

[0136] Optical zoom: 1.0x

[0137] Observation area: 129 μm × 129 μm

[0138] Resolution: 1024 pixels × 1024 pixels

[0139] Condition: Enable the auto tilt removal function of the laser microscope

[0140] Filter: Unfiltered

[0141] Air temperature: 24 ± 3 °C

[0142] Relative humidity: 63 ± 3 %

[0143] <Apparent volume (Vm)>

[0144] According to the standard ISO 25178-2:2012, the apparent volume (Vm) of the treated surface of the surface-treated copper foil was measured by surface texture analysis using a laser microscope (LEXT OLS5000-SAF, Olympus). The apparent volume (Vm) was obtained by setting the P1 and P2 values of the load ratio (mr) to 10 % and 80 %, respectively. The test results are also shown in Table 2 described below. The specific measurement conditions are as follows:

[0145] Light source wavelength: 405 nm

[0146] Objective lens magnification: 100x objective lens (MPLAPON-100x LEXT, Olympus)

[0147] Optical zoom: 1.0x

[0148] Observation area: 129 μm × 129 μm

[0149] Resolution: 1024 pixels × 1024 pixels

[0150] Condition: Enable the Auto tilt removal function of the laser microscope

[0151] Filter: unfiltered

[0152] Air temperature: 24 ± 3°C

[0153] Relative humidity: 63 ± 3%

[0154] <Reliability>

[0155] Stack six commercially available resin sheets (S7439G, SyTech Corp.) each with a thickness of 0.076 mm together to form a resin sheet stack layer, and place the surface-treated copper foil of any of the above embodiments on the resin sheet stack layer. Then, press the surface-treated copper foil onto the resin sheet stack layer to form a laminate. The pressing conditions are as follows: temperature 200°C, pressure 400 psi, and pressing time 120 minutes.

[0156] After that, perform a pressure cooker test (PCT), set the conditions in the oven to a temperature of 121°C, a pressure of 2 atm, and a humidity of 100% RH, and place the above laminate in the oven for 30 minutes. Then conduct a solder bath test, and immerse the laminate after the pressure cooker test in a molten solder bath at a temperature of 288°C for 10 seconds.

[0157] The solder bath test can be repeatedly performed on the same sample, and after each solder bath test is completed, observe whether there are any abnormal phenomena such as blisters, cracks, or delaminations on the laminate. If any of the above abnormal phenomena occur, it is determined that the laminate fails the solder bath test. The test results are also recorded in Table 2 described later. Among them:

[0158] A: After more than 50 solder bath tests, no abnormal phenomena occurred on the laminate

[0159] B: After 10 - 50 solder bath tests, abnormal phenomena occurred on the laminate

[0160] C: After less than 10 solder bath tests, abnormal phenomena occurred on the laminate

[0161] <Peel strength>

[0162] Six commercially available resin sheets (S7439G, SyTech Corporation.) each with a thickness of 0.076 mm were stacked together to form a resin sheet stack layer, and the surface-treated copper foil of any of the above embodiments was disposed on the resin sheet stack layer. Then, the surface-treated copper foil was laminated to the resin sheet stack layer to form a laminate. The lamination conditions were as follows: temperature 200 °C, pressure 400 psi, lamination time 120 minutes.

[0163] After that, according to JIS C 6471 standard, using a universal testing machine, the surface-treated copper foil was peeled from the laminate at an angle of 90°, and the test results are recorded in Table 2 described later.

[0164] <Signal transmission loss>

[0165] The surface-treated copper foil of any of the above embodiments was made into a strip-line, and its corresponding signal transmission loss was measured. Among them, the structure of the strip-line can be exemplified as Figure 3 shown. On a resin (S7439G from SyTech Corporation) of 152.4 μm, the surface-treated copper foil of any of the above embodiments was first laminated, and then the surface-treated copper foil was made into a wire 302. Then, two other resin sheets (S7439G, from SyTech Corporation's S7439G) were used to cover the two side surfaces respectively, so that the wire 302 was disposed in a resin carrier (S7439G, SyTech Corp.) 304. The strip-line 300 may further include two ground electrodes 306-1 and ground electrode 306-2, which are respectively disposed on opposite sides of the resin carrier 304. The ground electrode 306-1 and the ground electrode 306-2 can be electrically connected to each other through a conductive via, so that the ground electrode 306-1 and the ground electrode 306-2 have the same potential.

[0166] The specifications of each component in the strip-line 300 are as follows: the length of the wire 302 is 100 mm, the width w is 120 μm, and the thickness t is 35 μm; the Dk of the resin carrier 304 is 3.74, and the Df is 0.006 (measured with a 10 GHz signal according to IPC-TM 650 No 2.5.5.5); the characteristic impedance is 50 Ω.

[0167] According to the standard Cisco S3 method, using a signal analyzer (PNA N5230C network analyzer, Agilent), with the grounding electrodes 306-1 and 306-2 both at ground potential, an electrical signal is input from one end of the wire 302, and the output value at the other end of the wire 302 is measured to determine the signal transmission loss generated by the stripline 300. The specific measurement conditions are as follows: the electrical signal frequency is from 200 MHz to 15 GHz, the number of scan points is 6401, and the calibration method is TRL.

[0168] Finally, in the case where the electrical signal frequency is 8 GHz, the degree of signal transmission loss of the corresponding stripline is determined, and the test results are recorded in Table 2. Among them, the smaller the absolute value of the signal transmission loss, the less the loss degree of the signal during transmission. Specifically, when the absolute value of the signal transmission loss is greater than 0.8 dB / in, it represents poor signal transmission performance (Grade C); when the absolute value of the signal transmission loss is less than or equal to 0.8 dB / in and greater than or equal to 0.75 dB / in, it represents good signal transmission performance (Grade B); and when the absolute value of the signal transmission loss is less than 0.75 dB / in, it represents the best signal transmission performance (Grade A).

[0169] Table 2

[0170]

[0171]

[0172] According to the above-mentioned Examples 1-12, 14, 16, when the physical volume (Vm) of the processing surface is less than 1.90 μm 3 / μm 2 For the corresponding copper foil substrate and printed circuit board, in addition to having better peel strength (for example, higher than or equal to 3.52 lb / in), the surface-treated copper foil and the contacting carrier plate can also reduce the signal transmission loss generated when high-frequency electrical signals are transmitted in the conductive pattern (the signal transmission loss can reach at least Grade B).

[0173] According to the above-mentioned Examples 1-12, 16, when the physical volume (Vm) of the processing surface is 0.15 to 1.86 μm 3 / μm 2 , or is 0.25 to 0.85 μm 3 / μm 2 For the corresponding copper foil substrate and printed circuit board, it can more easily pass the reliability test.

[0174] According to the above-mentioned Examples 1-11, 14, when the physical volume (Vm) of the processing surface is less than 1.90 μm 3 / μm2 and when the arithmetic mean height (Sa) is from 0.10 to 2.00 μm, the peel strength between the surface-treated copper foil and the contacting carrier board can be further improved (for example, higher than or equal to 4.25 lb / in) for the corresponding copper foil substrate and printed circuit board.

[0175] According to the above-mentioned Embodiments 1-10, 14, and 16, when the solid volume (Vm) of the treated surface is less than 1.90 μm 3 / μm 2 and when the oxygen content in the surface-treated copper foil is less than 469 ppm or the hydrogen content is less than 40 ppm, it is easier to pass the reliability test for the corresponding copper foil substrate and printed circuit board.

[0176] According to the above embodiments of the present invention, by controlling the surface roughness parameters of the treated surface of the surface-treated copper foil, or controlling the hydrogen content and oxygen content of the surface-treated copper foil, for the corresponding copper foil substrate and printed circuit board, in addition to improving the adhesion and reliability between the surface-treated copper foil and the carrier board, the signal transmission loss generated when the high-frequency electrical signal is transmitted in the conductive pattern can also be reduced at the same time.

[0177] The above content is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those skilled in the technical field to which the present invention belongs, without departing from the concept of the present invention, several equivalent substitutions or obvious modifications can be made, and if the performance or use is the same, they should all be regarded as belonging to the protection scope of the present invention.

Claims

1. A surface-treated copper foil, characterized in that: including a processing surface, wherein the solid volume of the processing surface is less than 1.90 μm 3 / μm 2 , and the arithmetic mean height of the processing surface is 0.1 to 2.02 μm, and wherein the solid volume is obtained according to the standard method ISO 25178-2:2012 and is a value calculated in the range of 0% to 80% of the bearing ratio (mr).

2. The surface-treated copper foil according to claim 1, wherein: The solid volume of the processing surface is 0.11 to 1.86 μm 3 / μm 2 .

3. The surface-treated copper foil according to claim 1, wherein: The solid volume of the processing surface is 0.25 to 0.85 μm 3 / μm 2 .

4. The surface-treated copper foil according to claim 1, wherein: The arithmetic mean height of the treatment surface is 0.1 to 2 μm.

5. The surface-treated copper foil according to claim 1, wherein: The surface-treated copper foil further includes an electrolytic copper foil, and the oxygen content of the surface-treated copper foil is less than 469 ppm.

6. The surface-treated copper foil according to claim 1, wherein: The surface-treated copper foil further includes an electrolytic copper foil, and the hydrogen content of the surface-treated copper foil is less than 40 ppm.

7. The surface-treated copper foil according to claim 1, wherein: The surface-treated copper foil further includes an electrolytic copper foil and a surface treatment layer; the surface treatment layer is disposed on at least one surface of the electrolytic copper foil, and the outer side of the surface treatment layer is the treatment surface.

8. The surface-treated copper foil according to claim 7, wherein: The electrolytic copper foil includes a roll surface and a deposition surface on the opposite side of the roll surface, and the surface treatment layer is disposed on the roll surface.

9. The surface-treated copper foil according to claim 7, wherein: The surface treatment layer includes a sub-layer, and the sub-layer is a roughening layer.

10. The surface-treated copper foil according to claim 9, characterized in that: The roughening layer includes a plurality of roughening particles.

11. The surface-treated copper foil according to claim 9, wherein: The surface treatment layer further includes at least one other sub-layer, and the at least one other sub-layer is selected from the group consisting of a passivation layer and a coupling layer.

12. The surface-treated copper foil according to claim 11, wherein: The passivation layer contains at least one metal selected from the group consisting of nickel, zinc, chromium, cobalt, molybdenum, iron, tin, and vanadium.

13. A copper foil substrate, characterized in that: Comprising a carrier board and a surface-treated copper foil disposed on at least one surface of the carrier board; wherein, the surface-treated copper foil includes an electrolytic copper foil and a surface treatment layer, the surface treatment layer is disposed between the electrolytic copper foil and the carrier board, the surface treatment layer includes a treatment surface facing the carrier board, and the solid volume of the treatment surface is less than 1.90 μm 3 / μm 2 , and the arithmetic mean height of the treatment surface is 0.1 to 2.02 μm, and wherein, the solid volume is obtained according to the standard method ISO 25178-2:2012 and is a value calculated in the range of load ratio (mr) of 0% to 80%.

14. The copper foil substrate according to claim 13, wherein: The treatment surface of the surface treatment layer is in direct contact with the carrier plate.

15. The copper foil substrate according to claim 13, wherein: The solid volume of the processing surface is 0.25 to 0.85 μm 3 / μm 2 .

16. The copper foil substrate according to claim 13, wherein: The arithmetic mean height of the treatment surface is 0.10 to 2.00 μm.

17. The copper foil substrate according to claim 13, wherein: The oxygen content of the electrolytic copper foil is less than 469 ppm.

18. The copper foil substrate according to claim 13, wherein: The hydrogen content of the electrolytic copper foil is less than 40 ppm.

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