Copper material surface treatment process and treatment system

Abstract

The present invention discloses a copper material surface treatment process and treatment system, the copper material surface treatment process comprising: step S1, soaking the copper material to be treated, degreasing, and then drying; step S2, pickling the copper material, and then drying; step S3, placing the copper material in a chemical conversion treatment solution for a first set time; during the chemical conversion treatment process, using a second metal medium to contact the surface of the metal material; and then drying the copper material; step S4, hot pressing the LCP film and the copper material at a set high temperature for a second set time. The copper material surface treatment process and treatment system proposed by the present invention can deposit a chemical conversion film with low roughness and high reactivity on the surface of the copper material without power supply, so as to obtain a copper foil with high bonding strength to the LCP film, and the prepared copper material product can meet the high-speed transmission of signals at high frequencies.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface treatment, and relates to a surface treatment process, in particular to a copper material surface treatment process and a treatment system. Background Art

[0002] With the rapid development of 5G technology, the application demand for high frequency and high speed has put forward higher requirements on the transmission loss of materials, which has accelerated the development trend of high frequency application technology. At the same time, the expansion and enhancement of application product functions, such as photography, Bluetooth, Wi-Fi, 5G Internet access, fingerprint recognition and wireless charging devices, more and more functions need to be integrated together, making the design of high-speed and high-frequency substrate materials responsible for signal transmission functions, that is, flexible copper clad laminates, tend to be high-precision and high-density, and the demand for flexible copper clad laminates will also increase day by day.

[0003] As the substrate of high-frequency and high-speed circuit boards, copper foil has excellent electrical conductivity and thermal conductivity, which can effectively reduce signal transmission loss and provide good heat dissipation performance. At the same time, it has excellent mechanical strength and processing performance, good oxidation resistance, and lower cost than other metal materials. It is an ideal choice for making high-frequency and high-speed circuit boards. LCP-FCCL (liquid crystal polymer flexible copper clad laminate) is a high-performance flexible circuit board material based on liquid crystal polymer. It has excellent high-frequency characteristics, low dielectric constant, low water absorption and excellent dimensional stability. This material is widely used in 5G communications, high-speed transmission, consumer electronics and other fields, and is particularly suitable for electronic products that need to maintain stable performance in high-frequency and high-temperature environments. Due to its unique molecular structure, LCP-FCCL can provide excellent electrical properties while maintaining good flexibility, and is an indispensable key material in the modern electronics industry.

[0004] The bonding strength between copper foil and liquid crystal polymer (LCP) is weak, mainly because LCP has low surface energy and special molecular structure, which makes it difficult to form effective chemical bonding with copper foil. This makes it difficult to establish a solid bond between copper foil and LCP by traditional bonding methods.

[0005] At present, most solutions are to roughen the copper foil by electrolysis to improve the bonding strength. Chinese invention patent CN116397289A uses H2SO4 and electrolyte treatment through pretreatment to ensure the roughness and conductivity of the copper foil. Polymetallic oxoates or their derivatives are added to the roughening solution, and then the electroplating roughening solution is used to increase the roughness and mechanical riveting points of the copper foil. Chinese invention patent CN114990654B provides a surface treatment process for electrolytic copper foil, which sequentially carries out pickling, roughening, curing, alloying, chrome plating, and silane coupling agent dipping treatment processes to prepare copper foil with uniformly distributed copper nodules.

[0006] However, the electrolysis method has high equipment investment costs and requires the configuration of special electrolytic cells, power supplies and other equipment, which consumes a lot of energy and increases production costs. In addition, the electrolysis method will cause the copper foil surface to be highly roughened. According to the relationship between skin depth and frequency, when the signal transmission frequency exceeds 1GHz, the signal transmission is only carried out within the order of magnitude of the surface roughness, where the skin depth at 1GHz is 2μm, and the skin depth at 10GHz is only 0.66μm. According to signal transmission theory, the fluctuation of surface roughness will cause signal "standing waves" and "reflections", affecting signal transmission, increasing signal loss, and thus affecting the integrity of signal transmission under high-frequency and high-speed conditions.

[0007] In view of this, there is an urgent need to design a new metal surface treatment method to overcome at least part of the above-mentioned defects of the existing metal surface treatment methods. Summary of the invention

[0008] The present invention provides a copper material surface treatment process and a treatment system, which can deposit a chemical conversion film with low roughness and high reactivity on the surface of the copper material without electrolysis, thereby obtaining a copper material with high bonding strength to the LCP film, and the prepared copper foil product can meet the high-speed transmission of signals at high frequencies.

[0009] To solve the above technical problems, according to one aspect of the present invention, the following technical scheme is adopted: a copper material surface treatment process, the copper material surface treatment process comprising: a pickling step: pickling the copper material, and then drying the pickled copper material; a chemical conversion step: placing the copper material treated by the pickling step in a chemical conversion treatment liquid for a first set time; in the process of placing the copper material in the chemical conversion treatment liquid, using a second metal medium to contact the surface of the metal material; and then drying the copper material; a hot pressing bonding step: at a set high temperature, hot pressing the LCP film and the copper material treated by the chemical conversion step for a second set time.

[0010] As an embodiment of the present invention, in the chemical conversion step, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; thereby a potential difference is formed on the surface of the copper material, making the oxidation-reduction reaction of the chemical conversion treatment liquid on the surface of the copper material more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material.

[0011] As an embodiment of the present invention, the copper material surface treatment process further comprises a degreasing step before the pickling step: immersing the copper material to be treated, performing a degreasing treatment, and then drying the degreased copper material.

[0012] As an embodiment of the present invention, the copper material surface treatment process further includes a peeling test step: setting a peeling speed and a sample width to obtain a peeling strength.

[0013] As an embodiment of the present invention, the copper material surface treatment process specifically includes: step S1, soaking the copper material in acetone solution or weak alkaline solution, degreasing treatment, and then drying naturally at room temperature; step S1 is used as part of the pickling step; step S2, pickling the copper foil and then drying it at a temperature of 50~80°C; step S3, placing it in a chemical conversion treatment solution at 20~45°C for 10-30 min; during the treatment process, using a strip metal medium to contact the surface of the copper foil; step S3 is used as part of the chemical conversion step; step S4, after the treatment is completed, placing it in an oven at 50~80°C for drying; step S5, at 270~300°C, hot pressing the LCP film and the copper foil for 7~13 min; then through a peel test, the peeling speed is 5 mm / min, the sample width is 10 mm, and the peel strength is obtained; step S5 is used as part of the hot pressing bonding step.

[0014] As an embodiment of the present invention, the pickling solution is at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; the second metal medium is at least one of iron, nickel, aluminum and magnesium, and reacts with the chemical conversion treatment solution; the LCP film is Karary CTF, Karary CTQ, PRET LFR, PRET LFE, PRET LFT; the chemical conversion treatment liquid includes titanate, zirconate, ferrocyanide, fluoride and acidic aqueous solution; the titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, which can provide titanium ions when dissolved in water; the zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate and ammonium zirconate, and the zirconate can provide zirconium ions when dissolved in water; the ferrocyanide includes at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, which is a chemical conversion film forming promoter for promoting the precipitation of titanium zirconium compounds; the fluoride includes at least one of sodium fluoride, potassium fluoride and ammonium fluoride; the acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid.

[0015] According to another aspect of the present invention, the following technical scheme is adopted: a copper material surface treatment system, the copper material surface treatment system comprising: a pickling device for pickling the copper material; a chemical conversion device for placing the copper material treated by the pickling device in a chemical conversion treatment liquid for a first set time; in the process of placing the copper material in the chemical conversion treatment liquid, using a second metal medium to contact the surface of the metal material; a hot pressing bonding device for hot pressing the LCP film and the copper material treated by the chemical conversion device at a set high temperature for a second set time.

[0016] As an embodiment of the present invention, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; during the chemical conversion process of the chemical conversion device, a potential difference is generated on the surface of the copper material, so that the redox reaction of the chemical conversion treatment liquid on the surface of the copper material is more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material.

[0017] As an embodiment of the present invention, the copper material surface treatment system further includes: a degreasing device for immersing the copper material to be treated for degreasing treatment; a drying device for drying the copper material; a peeling test device for setting the peeling speed and sample width, and performing a peeling test on the LCP film and the copper material after hot pressing to obtain the peeling strength.

[0018] As an embodiment of the present invention, the pickling solution is at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; the second metal medium is at least one of iron, nickel, aluminum and magnesium, and reacts with the chemical conversion treatment solution; the LCP film is Karary CTF, Karary CTQ, PRET LFR, PRET LFE, PRET LFT; the chemical conversion treatment liquid includes titanate, zirconate, ferrocyanide, fluoride and acidic aqueous solution; the titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, which can provide titanium ions when dissolved in water; the zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate and ammonium zirconate, and the zirconate can provide zirconium ions when dissolved in water; the ferrocyanide includes at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, which is a chemical conversion film forming promoter for promoting the precipitation of titanium zirconium compounds; the fluoride includes at least one of sodium fluoride, potassium fluoride and ammonium fluoride; the acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid.

[0019] The beneficial effects of the present invention are as follows: the copper material surface treatment process and treatment system proposed in the present invention adopt chemical conversion treatment (without electrolysis) to deposit a chemical conversion film with low roughness and high reactivity on the surface of the copper material (such as copper foil), thereby obtaining a copper material with high bonding strength to the LCP film, and the prepared copper material product can meet the high-speed transmission of signals at high frequencies.

[0020] The present invention can increase the roughness of the copper foil surface through surface treatment, forming a larger contact area and mechanical locking effect; at the same time, it can also increase the surface energy of the copper foil, improve its chemical compatibility with LCP, and enable the two materials to form a stronger interface bond. In addition, the surface treatment can also remove oxides and pollutants on the surface of the copper foil to ensure a good bonding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a flow chart of a copper material surface treatment process according to an embodiment of the present invention.

[0022] Figure 2 Schematic diagram of the composition of a copper material surface treatment system in one embodiment of the present invention.

[0023] Figure 3 Schematic diagram of SEM and XPS results of the original copper foil surface.

[0024] Figure 4 Schematic diagram of SEM and XPS results of the copper foil surface in Example 3 of the present invention.

[0025] Figure 5 This is a schematic diagram of the SEM results of the copper foil surface of Comparative Example 3 of the present invention.

[0026] Figure 6 The figure is a schematic diagram of the roughness comparison results of various embodiments of the present invention and the comparative example. DETAILED DESCRIPTION

[0027] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0028] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0029] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments. The same or similar prior art means and some technical features in the embodiments are mutually replaced within the scope of the present invention.

[0030] Unless otherwise indicated, implied from the context, or customary in the prior art, all parts and percentages in this application are based on weight, and the test and characterization methods used are all current as of the filing date of this application. Where applicable, the contents of any patent, patent application or publication referred to in this application are fully incorporated herein by reference, and their equivalent patent families are also incorporated by reference, especially the definitions of synthesis techniques, product and processing designs, polymers, comonomers, initiators or catalysts disclosed in these documents in the art. If the definition of a specific term disclosed in the prior art is inconsistent with any definition provided in this application, the definition of the term provided in this application shall prevail.

[0031] Numerical ranges in this application are approximate values, so unless otherwise specified, they may include numerical values ​​outside the range. Numerical ranges include all numerical values ​​from the lower limit to the upper limit increased by 1 unit, provided that there is an interval of at least 2 units between any lower value and any higher value. For example, if the recorded component, physical or other properties (such as molecular weight, melt index, etc.) are 100 to 1000, it means that all single values ​​are clearly listed, such as 100, 101, 102, etc., and all sub-ranges, such as 100 to 166, 155 to 170, 198 to 200, etc. For a range containing a numerical value less than 1 or containing a fraction greater than 1 (such as 1.1, 1.5, etc.), 1 unit is appropriately regarded as 0.0001, 0.001, 0.01 or 0.1. For a range containing a single digit less than 10 (such as 1 to 5), 1 unit is usually regarded as 0.1. These are only specific examples of what is intended to be expressed, and all possible combinations of values ​​between the lowest and highest values ​​listed are considered to be clearly recorded in this application. It should also be noted that the terms "first", "second", etc. in this article do not limit the order of precedence, but are only used to distinguish substances with different structures.

[0032] When used with respect to chemical compounds, unless expressly specified otherwise, the singular includes all isomeric forms and vice versa (e.g., "hexane" includes all isomers of hexane, individually or collectively). In addition, nouns using "a," "an," or "the" also include their plural forms unless expressly specified otherwise.

[0033] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any other components, steps or processes, and are irrelevant to whether these other components, steps or processes are disclosed in this application. To eliminate any doubt, unless explicitly stated, all compositions using the terms "comprising", "including", or "having" in this application may include any additional additives, adjuvants or compounds. On the contrary, except for those necessary for operating performance, the term "essentially consisting of..." excludes any other components, steps or processes from the scope of any description of the term below. The term "consisting of..." does not include any components, steps or processes that are not specifically described or listed. Unless explicitly stated, the term "or" refers to the listed individual members or any combination thereof.

[0034] The description of the steps in each embodiment in the specification is only for the convenience of explanation, and the implementation method of the present application is not limited by the order of implementation of the steps.

[0035] The invention discloses a copper material surface treatment process. Figure 1 This is a flow chart of a copper material surface treatment process according to an embodiment of the present invention; please refer to Figure 1 , the copper material surface treatment process includes:

[0036] Step S2, pickling step: pickling the copper material, and then drying the pickled copper material. In one embodiment of the present invention, the pickling solution used in the pickling step can be at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; in one embodiment, the pickling solution is a 0.1 mol / L sulfuric acid solution (the concentration can also be other concentrations, such as 0.12 mol / L; the pickling solution can also be a solution of hydrochloric acid, nitric acid, etc.).

[0037] Step S3, chemical conversion step: placing the copper material treated by the pickling step in the chemical conversion treatment liquid for a first set time; in the process of placing the copper material in the chemical conversion treatment liquid, using the second metal medium to contact the surface of the metal material; and then drying the copper material. In one embodiment of the present invention, in the chemical conversion step, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; thereby a potential difference is formed on the surface of the copper material, so that the oxidation-reduction reaction of the chemical conversion treatment liquid on the surface of the copper material is more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material. In one embodiment, the second metal medium can be at least one of iron, nickel, aluminum, and magnesium; if the second metal medium is an iron material or an aluminum material, it can also include both iron and aluminum materials. The second metal medium can be a second metal medium in the shape of a wire or a strip (wherein the wire shape can also be regarded as a kind of strip shape, such as an iron wire can be regarded as a strip-shaped second metal medium), and of course it can also be other shapes, such as an ellipse, a circle, a square or an irregular shape.

[0038] Hot pressing and laminating step: hot pressing and laminating the LCP film and the copper material treated by the chemical conversion step for a second set time at a set high temperature. In one embodiment of the present invention, the LCP film is one of Karary CTF, Karary CTQ, PRETLFR, PRET LFE, and PRET LFT, or a combination of two or more of the above materials.

[0039] The chemical conversion treatment liquid may include titanate, zirconate, ferrocyanide, fluoride and an acidic aqueous solution. The titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, which can provide titanium ions when dissolved in water; in one embodiment, the titanate includes sodium hexafluorotitanate. The zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate and ammonium zirconate, which can provide zirconium ions when dissolved in water; in one embodiment, the zirconate includes sodium hexafluorozirconate. Ferrocyanide includes at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, which is a chemical conversion film-forming promoter for promoting the precipitation of titanium zirconium compounds; in one embodiment, the ferrocyanide includes potassium ferrocyanide. The fluoride includes at least one of sodium fluoride, potassium fluoride and ammonium fluoride; in one embodiment, the fluoride includes sodium fluoride. The acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid; in one embodiment, the acidic aqueous solution includes sulfuric acid.

[0040] In one embodiment of the present invention, the copper material surface treatment process further comprises step S1, a degreasing step, before the pickling step: soaking the copper material to be treated, performing a degreasing treatment, and then drying the degreased copper material.

[0041] In addition, after the treatment is completed, the copper material surface treatment process may further include a peeling test step: setting a peeling speed and a sample width to obtain a peeling strength.

[0042] In one embodiment of the present invention, the copper material surface treatment process specifically includes:

[0043] Step S1, soaking the copper material in acetone solution or weak alkaline solution for degreasing treatment; then drying it naturally at room temperature; wherein the weak alkaline solution can be a weak alkaline solution composed of bicarbonate that can undergo saponification reaction with oil.

[0044] Step S2, pickling the copper foil and then drying it at a temperature of 50-80°C (the temperature may be 50°C, 65°C, 70°C, 80°C, etc.).

[0045] Step S3, placing in a chemical conversion treatment solution at 20-45°C (temperature can be 20°C, 25°C, 30°C, 45°C, etc.) for 10-30 minutes (time can be 10 minutes, 20 minutes, 30 minutes, etc.); during the treatment process, a strip-shaped second metal medium is used to contact the surface of the copper foil.

[0046] Step S4: After the treatment is completed, place the product in an oven at 50-80°C (the temperature can be 50°C, 65°C, 70°C, 80°C, etc.) for drying.

[0047] Step S5, at 270-300°C (the temperature can be 270°C, 275°C, 280°C, 300°C, etc.), hot press the LCP film and the copper foil for 7-13 min (the time can be 7 min, 10 min, 13 min, etc.); then perform a peel test with a peel speed of 5 mm / min and a sample width of 10 mm to obtain the peel strength (the parameters selected in the peel test can be set as needed, and other parameters can be selected).

[0048] The present invention further discloses a copper material surface treatment system, Figure 2 This is a schematic diagram of the composition of a copper material surface treatment system in one embodiment of the present invention; please refer to Figure 2 The copper material surface treatment system includes: a pickling device 1, a chemical conversion device 2 and a hot pressing bonding device 3.

[0049] The pickling device 1 is used to pickle the copper material. In one embodiment of the present invention, the pickling solution used by the pickling device can be at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; in one embodiment, the pickling solution is a 0.1 mol / L sulfuric acid solution (the concentration can also be other concentrations, such as 0.12 mol / L; the pickling solution can also be selected from hydrochloric acid, nitric acid and other solutions).

[0050] The chemical conversion device 2 is used to place the copper material treated by the pickling device in the chemical conversion treatment liquid for a first set time; during the process of placing the copper material in the chemical conversion treatment liquid, a second metal medium is used to contact the surface of the metal material. In one embodiment of the present invention, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; during the chemical conversion process of the chemical conversion device, a potential difference is formed on the surface of the copper material, so that the oxidation-reduction reaction of the chemical conversion treatment liquid on the surface of the copper material is more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material. In one embodiment of the present invention, during the chemical conversion process of the chemical conversion device 2, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; thus, a potential difference is formed on the surface of the copper material, so that the oxidation-reduction reaction of the chemical conversion treatment liquid on the surface of the copper material is more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material. In one embodiment, the second metal medium can be at least one of iron, nickel, aluminum, and magnesium; if the second metal medium is an iron material or an aluminum material, it can also include both iron and aluminum materials.

[0051] The chemical conversion treatment liquid may include titanate, zirconate, ferrocyanide, fluoride and an acidic aqueous solution. The titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, which can provide titanium ions when dissolved in water; in one embodiment, the titanate includes sodium hexafluorotitanate. The zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate and ammonium zirconate, which can provide zirconium ions when dissolved in water; in one embodiment, the zirconate includes sodium hexafluorozirconate. Ferrocyanide includes at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, which is a chemical conversion film-forming promoter for promoting the precipitation of titanium zirconium compounds; in one embodiment, the ferrocyanide includes potassium ferrocyanide. The fluoride includes at least one of sodium fluoride, potassium fluoride and ammonium fluoride; in one embodiment, the fluoride includes sodium fluoride. The acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid; in one embodiment, the acidic aqueous solution includes sulfuric acid.

[0052] The heat-pressing laminating device 3 is used to heat-press the LCP film and the copper material treated by the chemical conversion device for a second set time at a set high temperature. In one embodiment of the present invention, the LCP film is one of Karary CTF, Karary CTQ, PRET LFR, PRET LFE, and PRET LFT, or a combination of two or more of the above materials.

[0053] In one embodiment of the present invention, the copper material surface treatment system further comprises: a degreasing device 4, a drying device 5 and a peeling test device 6. The degreasing device 4 is used to soak the copper material to be treated and perform a degreasing treatment. The drying device 5 is used to dry the copper material, and the drying device 5 can be used in the treatment of multiple copper material treatment processes. The peeling test device 6 is used to set the peeling speed and sample width, and perform a peeling test on the LCP film and the copper material after hot pressing to obtain the peeling strength.

[0054] Surface characterization (XPS, SEM, water contact angle) experiment of copper foil: XPS and SEM are used to observe the changes in the surface properties of copper foil before and after treatment, and the water contact angle experiment is used to characterize the changes in the surface energy of copper foil; peeling test is used to determine the bonding strength between copper foil and LCP; AFM is used to measure the surface roughness of copper foil treated with different methods.

[0055] Example 1

[0056] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70℃ oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 24g / L sodium hexafluorotitanate, 8g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride. Use 0.1mol / L sulfuric acid to adjust the solution to pH 2. Place the iron wire close to the surface of the copper foil and treat it at 25℃ for 10 minutes. Then, place the copper foil in a 70℃ oven until the surface moisture is completely dried.

[0057] The treated copper foil and Karary CTF were hot pressed for 10 minutes in a hot press at a pressure of 10MPa and a temperature of 295°C to obtain a laminated composite, which was then tested according to the IPC-TM-6502.4.8 test method. The flexible copper clad laminate was used to make a peeling test sample with a width of 1mm. At room temperature, the bonding surface of the LCP layer and the metal layer was peeled off from the edge, and the metal layer was fixed on the flat plate with a double-sided tape. The liquid crystal polymer film layer was peeled off in a 180° direction at a speed of 50mm / min, and the peeling load was recorded with a tensile tester. The samples with a peeling length greater than 100mm were taken as valid samples, and the peeling strength was calculated based on the average value of the load during the peeling process.

[0058] Example 2

[0059] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 18g / L sodium hexafluorotitanate, 6g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride, use 0.1mol / L sulfuric acid to adjust the solution to pH 2, place the iron wire close to the surface of the copper foil, and treat it at 25°C for 10 minutes. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0060] Example 3

[0061] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 32g / L sodium hexafluorotitanate, 12g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride, use 0.1mol / L sulfuric acid to adjust the solution to pH 2, place the iron wire close to the surface of the copper foil, and treat it at 25°C for 10 minutes. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0062] Example 4

[0063] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 24g / L sodium hexafluorotitanate, 8g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride, use 0.1mol / L sulfuric acid to adjust the solution to pH 2, place the iron wire close to the surface of the copper foil, and treat it at 25°C for 20 minutes. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0064] Example 5

[0065] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 24g / L sodium hexafluorotitanate, 8g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride, use 0.1mol / L sulfuric acid to adjust the solution to pH 2, place the iron wire close to the surface of the copper foil, and treat it at 25°C for 30 minutes. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0066] Comparative Example 1

[0067] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, place the copper foil directly in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 32g / L sodium hexafluorotitanate, 12g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride. Use 0.1mol / L sulfuric acid to adjust the solution to pH 2. Place the iron wire close to the surface of the copper foil and treat at 25°C for 10 minutes. Next, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0068] Comparative Example 2

[0069] Soak a 5cm×5cm copper foil in acetone for 30 minutes for degreasing. After drying naturally at room temperature, soak the copper foil in 0.1mol / L sulfuric acid for 10 minutes to remove the native oxide layer on the surface of the copper foil. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. Immerse the copper foil in a solution containing 32g / L sodium hexafluorotitanate, 12g / L sodium hexafluorozirconate, 15g / L potassium ferrocyanide, and 5g / L sodium fluoride, use 0.1mol / L sulfuric acid to adjust the solution to pH 2, and treat at 25°C for 10 minutes. Then, place the copper foil in a 70°C oven until the surface moisture is completely dried. The other steps can be consistent with the corresponding steps of Example 1.

[0070] Comparative Example 3

[0071] A commercially available copper foil prepared by electrolysis was selected and hot-pressed with LCP to prepare a laminated composite board.

[0072] Table 1 Comparison of treated copper foil results

[0073] Experimental Examples Water contact angle (°) <![CDATA[Surface energy (mJ / m 2 )]]> Peel strength (N / mm) Example 1 65.1 43.8 0.32 Example 2 70.6 39.4 0.45 Example 3 49.1 53.1 0.86 Example 4 58.9 47.8 0.57 Example 5 55.5 49.7 0.79 Comparative Example 1 60.3 45.7 0.39 Comparative Example 2 64.3 44.1 0.34 Comparative Example 3 59.1 46.8 0.70

[0074] It can be seen from the data of Examples 1 to 3 in Table 1 that with the increase in the concentration of titanium salt and zirconium salt in the treatment solution, the coverage area of ​​the chemical conversion film on the copper foil surface gradually increases, and the hydrophilicity and surface energy gradually increase. This indirectly proves that the active substances on its surface gradually increase, thereby increasing the chemical reaction between the copper foil and the LCP film, thereby increasing the interface bonding strength, and thus the peel strength is improved.

[0075] It can be seen from the data of Example 1 and Examples 4 and 5 in Table 1 that as the treatment time increases, the coverage area of ​​the chemical conversion film on the copper foil surface gradually increases, which also leads to an increase in the peel strength.

[0076] It can be seen from the data of Example 3 and Comparative Example 1 in Table 1 that the pickling pretreatment is beneficial to the deposition of the chemical conversion film, thereby improving the interface bonding strength.

[0077] From Example 3 and Comparative Example 2 in Table 1 and Figure 6 It can be seen from the data that the use of iron wire contact can significantly improve the deposition of the chemical conversion film. The iron wire changes the surface potential of the copper foil, thereby promoting the occurrence of redox reactions on the surface of the copper foil, thereby promoting the formation of titanium-zirconium chemical conversion film and significantly improving the interface bonding strength.

[0078] from Figures 3 to 5 It can be seen that the titanium-zirconium chemical conversion treatment does not significantly change the surface morphology of the copper foil, while the electrolytic method will cause obvious holes on the surface of the copper foil. Figure 5 As shown in the figure, the electrolysis method will significantly increase the surface roughness of the copper foil, which is also due to the presence of holes on the surface of the copper foil. After the chemical conversion method, the surface roughness of the copper foil is almost below 0.5μm, which is extremely low and meets the performance requirements of high transmission frequency, high speed and low loss under 5G signals.

[0079] After chemical conversion treatment, the wettability of LCP to copper foil is significantly improved. After peeling, some LCP will remain on the surface of copper foil. This is because the interface bonding strength is significantly improved, achieving a bonding effect equivalent to that of commercially available electrolytic copper foil.

[0080] The present invention uses a simple chemical conversion treatment without power supply to deposit a chemical conversion film with low roughness and high reactivity on the surface of the copper foil, thereby obtaining a copper foil with high bonding strength to the LCP film, and the prepared copper foil product can meet the high-speed transmission of signals at high frequencies.

[0081] In summary, the copper material surface treatment process and treatment system proposed in the present invention adopt chemical conversion treatment (without electrolysis) to deposit a chemical conversion film with low roughness and high reactivity on the surface of the copper material (such as copper foil), thereby obtaining a copper material with high bonding strength to the LCP film, and the prepared copper material product can meet the high-speed transmission of signals at high frequencies.

[0082] The present invention can increase the roughness of the copper foil surface through surface treatment, forming a larger contact area and mechanical locking effect; at the same time, it can also increase the surface energy of the copper foil, improve its chemical compatibility with LCP, and enable the two materials to form a stronger interface bond. In addition, the surface treatment can also remove oxides and pollutants on the surface of the copper foil to ensure a good bonding effect.

[0083] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The description and application of the present invention here are illustrative, and it is not intended to limit the scope of the present invention to the above-mentioned embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. The deformation and change of the embodiments disclosed here are possible, and the replacement of the embodiments and the various equivalent parts are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential features of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A copper material surface treatment process, characterized in that: The copper material surface treatment process comprises: Pickling step: pickling the copper material, and then drying the pickled copper material; Chemical conversion step: placing the copper material treated in the pickling step in a chemical conversion treatment solution for a first set time; while the copper material is placed in the chemical conversion treatment solution, contacting the surface of the metal material with a second metal medium; and then drying the copper material; Hot-pressing laminating step: hot-pressing the LCP film and the copper material treated by the chemical conversion step for a second set time at a set high temperature; Wherein, the chemical conversion treatment liquid includes titanate, zirconate, ferrocyanide, fluoride and acidic aqueous solution; In the chemical conversion step, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; thereby forming an electric potential difference on the surface of the copper material, making the redox reaction of the chemical conversion treatment liquid on the surface of the copper material more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material.

2. The copper material surface treatment process according to claim 1, characterized in that: The copper material surface treatment process further comprises a degreasing step before the pickling step: soaking the copper material to be treated, performing a degreasing treatment, and then drying the degreased copper material.

3. The copper material surface treatment process according to claim 1, characterized in that: The copper material surface treatment process further includes a peeling test step: setting a peeling speed and a sample width to obtain a peeling strength.

4. The copper material surface treatment process according to claim 1, characterized in that: The copper material surface treatment process specifically includes: Step S1, soaking the copper material in an acetone solution or a weak alkaline solution for degreasing, and then drying it naturally at room temperature; the step S1 is a part of the pickling step; Step S2, pickling the copper foil and then drying it at a temperature of 50-80°C; Step S3, placing in a chemical conversion treatment solution at 20-45°C for 10-30 min; during the treatment process, a strip metal medium is used to contact the surface of the copper foil; the step S3 is a part of the chemical conversion step; Step S4: After the treatment is completed, place in an oven at 50-80°C for drying; Step S5, at 270-300°C, hot-press the LCP film and the copper foil for 7-13 min; then, through a peel test, the peel speed is 5 mm / min, the sample width is 10 mm, and the peel strength is obtained; the step S5 is a part of the hot-press bonding step.

5. The copper material surface treatment process according to claim 1, characterized in that: The pickling solution used in the pickling step is at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; The second metal medium is at least one of iron, nickel, aluminum and magnesium, and reacts with the chemical conversion treatment liquid; The LCP film is at least one of Karary CTF, Karary CTQ, PRET LFR, PRET LFE, and PRET LFT; The titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, and can provide titanium ions when dissolved in water; The zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate, and ammonium zirconate, and the zirconate is dissolved in water to provide zirconium ions; The ferrocyanide comprises at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, and is used as a film-forming promoter for chemical conversion film to promote the precipitation of titanium zirconium compound; The fluoride comprises at least one of sodium fluoride, potassium fluoride and ammonium fluoride; The acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid.

6. A copper material surface treatment system, characterized in that: The copper material surface treatment system comprises: A pickling device, used for pickling copper materials; A chemical conversion device, used to place the copper material treated by the pickling device in a chemical conversion treatment solution for a first set time; while the copper material is placed in the chemical conversion treatment solution, a second metal medium is used to contact the surface of the metal material; A hot pressing laminating device, used for hot pressing the LCP film and the copper material treated by the chemical conversion device at a set high temperature for a second set time; Wherein, the chemical conversion treatment liquid includes titanate, zirconate, ferrocyanide, fluoride and acidic aqueous solution; In the chemical conversion step, the second metal medium reacts more actively with the chemical conversion treatment liquid than the copper material; thereby forming an electric potential difference on the surface of the copper material, making the redox reaction of the chemical conversion treatment liquid on the surface of the copper material more intense at the second metal medium, thereby promoting the deposition of metal compounds in the chemical conversion treatment liquid on the surface of the copper material.

7. The copper material surface treatment system according to claim 6, characterized in that: The copper material surface treatment system further comprises: A degreasing device, used for soaking the copper material to be treated and performing degreasing treatment; A drying device, used to dry the copper material; The peeling test device is used to set the peeling speed and sample width, and to perform a peeling test on the LCP film and copper material after heat pressing to obtain the peeling strength.

8. The copper material surface treatment system according to claim 6, characterized in that: The pickling solution used in the pickling device is at least one of sulfuric acid, hydrochloric acid, nitric acid and hydrofluoric acid; The second metal medium is at least one of iron, nickel, aluminum and magnesium, and reacts with the chemical conversion treatment liquid; The LCP film is at least one of Karary CTF, Karary CTQ, PRET LFR, PRET LFE, and PRET LFT; The titanate includes at least one of hexafluorotitanic acid, sodium hexafluorotitanate, calcium hexafluorotitanate, potassium titanate, sodium titanate and ammonium titanate, and can provide titanium ions when dissolved in water; The zirconate includes one or more of hexafluorozirconic acid, sodium hexafluorozirconate, potassium zirconate, and ammonium zirconate, and the zirconate can provide zirconium ions when dissolved in water; The ferrocyanide comprises at least one of potassium ferrocyanide, sodium ferrocyanide and ammonium ferrocyanide, and is used as a film-forming promoter for chemical conversion film to promote the precipitation of titanium zirconium compound; The fluoride comprises at least one of sodium fluoride, potassium fluoride and ammonium fluoride; The acidic aqueous solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid.

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