A production method and application of ultra-low profile HVLP electrolytic copper foil

Abstract

The present invention discloses a production method and use of an ultra-low profile HVLP electrolytic copper foil, which belongs to the technical field of electrolytic copper foil, and aims to solve the problem of preventing the introduction of non-copper metals as much as possible in the processability of copper foil. The method includes additive-assisted electrochemical deposition of ultra-low profile raw foil, additive-assisted electrochemical fine roughening treatment, zero-content ferromagnetic functional layer construction, and chemical bonding layer adaptation and construction. The ultra-low profile electrolytic copper foil produced by the method of the present invention has typical characteristics such as ultra-low surface profile, fine roughening structure, special morphology coarsening structure, no ferromagnetic metal content, stable anti-peeling performance, and excellent signal integrity; when processing copper clad laminate products, the bonding strength between the electrolytic copper foil and the resin substrate is also sufficient. And because the product does not contain ferromagnetic metal content, as a raw material for PCB products, it fundamentally eliminates the adverse effects of ferromagnetic metals on signal transmission and ensures signal integrity.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic copper foil, and in particular relates to a method for producing ultra-low profile electrolytic copper foil and a method for producing a printed circuit board thereof. Background Art

[0002] High-performance electronic circuit copper foil is an indispensable key raw material for 5G communications and high-speed server applications. Entering the era of high-speed digital lines and millimeter-wave communications, the requirements for signal integrity (SI), power integrity (PI) and electromagnetic compatibility (EMC) in the new generation of printed circuit boards (PCBs) have also risen with the iteration and upgrading of technology. As a conductor for signal transmission in PCBs, the performance of electronic circuit copper foil itself and the process in the subsequent processing play a decisive role in signal transmission performance.

[0003] According to the signal transmission theory, the signal loss in PCB is α totalc Can be divided into dielectric loss α dielectric , conductor loss α conductor , radiation loss α radiation and leakage loss α leakage .

[0004] (Formula 1)

[0005] Among them, conductor loss is mainly related to the copper foil as the signal transmission medium, dielectric loss is mainly related to the dielectric material used in the PCB, and radiation loss and leakage loss are generally closely related to the design of the circuit board. It should be pointed out that in addition to being related to the roughness of the copper foil itself, conductor loss is also directly affected by the frequency of the transmitted signal.

[0006] Previous research on conductor loss focused on the roughness of the copper foil itself. Our patent application 2023100730323, "A method for producing ultra-low profile copper foil for high-frequency and high-speed PCBs", disclosed that reducing the surface roughness of copper foil is beneficial to suppressing the skin effect and reducing the heat loss generated by the copper foil during signal transmission, thereby improving signal transmission integrity.

[0007] In order to ensure the reliability of PCB during processing, a certain bonding strength needs to be maintained between the copper foil and the plate. The side where the copper foil is pressed against the plate needs to be roughened, while taking into account the adverse effects of increased roughness on signal transmission. In the proposal "A method for producing ultra-low profile copper foil for high-frequency and high-speed PCBs" proposed by our company, a fine roughening treatment is performed on the surface of the ultra-low roughness copper foil, which not only ensures a lower profile, but also meets the bonding strength between the copper foil and the prepreg.

[0008] The manufacturing process of the HVLP copper foil can be mainly divided into three stages: ultra-low profile electrolytic foil production and ultra-fine roughened surface treatment. In the ultra-low profile electrolytic foil production process, the electrochemical crystallization and growth process are regulated by the synergistic effect of additives to achieve controllable growth of ultra-low profile foil. In the ultra-fine surface treatment process, the controllable micromorphology and growth of fine roughened tissue are achieved by matching additives and current processes.

[0009] Further research based on this invention application has led to new findings: Due to the difference in electrical conductivity and magnetic permeability, the non-copper metal introduced during the surface treatment process to improve the processability of copper foil will also have an adverse effect on signal transmission, and this adverse effect is directly related to the conductor loss α conductor Therefore, based on the original research and development results, it is also necessary to strictly control the content of non-copper metals in the surface treatment process of HVLP copper foil, and reduce the content of non-copper metals as much as possible while ensuring the processability of copper foil.

[0010] In response to this new discovery, it is necessary to re-explore a method that can achieve the extremely low profile, controllable micromorphology, and ultra-fine coarsened particles of the original research and development results "A method for producing ultra-low profile copper foil for high-frequency and high-speed PCBs", while also avoiding the introduction of non-copper metals in the copper foil machinability as much as possible to ensure better signal transmission performance based on the original performance.

[0011] Based on the problems in the above background technology, researchers have proposed another production method and use of ultra-low profile HVLP electrolytic copper foil. Summary of the invention

[0012] The object of the present invention is to provide a production method of an ultra-low profile HVLP electrolytic copper foil and its use, so as to solve the problem of preventing the introduction of non-copper metals as much as possible in the processability of the copper foil, so as to further improve the signal transmission performance of the copper foil.

[0013] In order to solve the above problems, the technical solution of the present invention is:

[0014] A production method of ultra-low profile HVLP electrolytic copper foil and its use, the method is divided into the following steps:

[0015] S1, additive-assisted electrochemical deposition of ultra-low profile green foil;

[0016] A brightener for refining grain size, a displacement agent for enhancing additive wetting in the titanium cathode, and a leveler for improving the uniformity of electrochemical deposition of copper foil are introduced into the acidic copper sulfate solution. Through the coordinated effect of the above three types of additives, a raw foil with an ultra-low profile rough surface is generated by electrochemical deposition on the roller surface of the titanium cathode under the action of direct current.

[0017] S2, additive-assisted electrochemical micro-roughening treatment and curing;

[0018] The rough surface of the ultra-low profile raw foil generated in S1 is selected as the treatment surface, and after the unwinding end is unwound, the copper foil is run into an electrolytic tank containing an additive for fine roughening treatment, and the electrolytic copper foil after the ultra-fine roughening treatment is washed with water, squeezed dry, and then transferred to a curing tank for curing treatment;

[0019] S3, construction of zero-content ferromagnetic functional layer;

[0020] In order to improve the anti-oxidation performance of electrolytic copper foil in the downstream processing, the smooth and rough surfaces of the electrolytic copper foil need to be passivated. This process does not introduce non-copper metal elements containing ferromagnetism. The content of ferromagnetic components such as nickel and cobalt in the barrier layer is 0mg / m 2 , that is, constructing a zero-content ferromagnetic functional layer;

[0021] S3.1 Double-sided electrodeposition of zinc-containing barrier layer;

[0022] The zinc barrier layer is deposited on the smooth and matte surfaces of the finely roughened copper foil in sequence through an electrochemical deposition process, and the zinc content of the matte and smooth surfaces is strictly controlled to 15-30g / m 2 To improve the high temperature oxidation resistance of copper foil;

[0023] S3.2 Double-sided electrodeposition of chromium-containing passivation layer;

[0024] At the same time, a chromium-containing functional layer is electrodeposited to improve the weather resistance of the copper foil at room temperature;

[0025] S4, chemical bonding layer adaptation and construction;

[0026] A chemical bonding layer is constructed on the matte surface of the ultra-low profile electrolytic copper foil, and a silane coupling agent matching the resin functional group is selected in a targeted manner; the copper foil after passivation treatment is run into a silane coupling agent treatment tank, and a chemical bonding layer is applied to the matte surface after roughening and passivation treatment by roller coating;

[0027] The product produced by the above process is ultra-low profile HVLP electrolytic copper foil.

[0028] Furthermore, the brightener in S1 is one or more of organic additives containing mercapto or sulfonic acid groups, such as thiourea, sodium polydisulfide propane sulfonate (SPS), sodium 3-mercaptopropane sulfonate (MPS), and sodium allyl sulfonate (ALS), and the content of the brightener in the electrolyte is between 5-10ppm.

[0029] Furthermore, the moving agent in S1 is one or more of chain ether polymers such as polyethylene glycol (PEG) and polypropylene glycol (PPG), and the content of the moving agent in the electrolyte is between 10-20 ppm.

[0030] Furthermore, the leveling agent in S1 is a nitrogen-containing organic compound such as gelatin, collagen, hydroxyethyl cellulose (HEC), etc., and the content of the leveling agent in the electrolyte is between 10-20 ppm.

[0031] Furthermore, the additives used in the fine roughening process in S2 are polyoxometalates (POMs) and their derivatives, including but not limited to one or more of potassium tungstophosphate, sodium molybdosilicate, sodium molybdophosphate, sodium molybdocobaltate, sodium thiomolybdate, and sodium thiosilicate; the concentration of the additives in the roughening electrolyte is between 10-30ppm.

[0032] Furthermore, the silane coupling agent used in S4 is one of epoxy, amino, vinyl, acrylic, and mercapto silane coupling agents, and the silicon concentration is between 0.1-1.0wt%.

[0033] Furthermore, the parameters of the electrochemical deposition process of the green foil in S1 are as follows:

[0034] Cu 2+ Concentration: 80g / L;

[0035] H 2 SO 4 Concentration: 200g / L;

[0036] Cl - Concentration: 15ppm;

[0037] Electrolyte temperature: 55°C;

[0038] Electrolyte flow rate: 40m 3 / h;

[0039] Current density: 80A / dm 2 ;

[0040] S2 is divided into the following two steps:

[0041] The specific parameters of S2.1 ultra-fine roughening process are as follows:

[0042] Cu2+ Ion concentration: 15g / L;

[0043] H 2 SO 4 Concentration: 150g / L;

[0044] Electrolyte temperature: 30°C;

[0045] Roughening liquid flow rate: 10.0m 3 / h;

[0046] Average current density: 2500A / m 2 ;

[0047] Processing time: 10s;

[0048] The specific parameters of the S2.2 curing stage are as follows:

[0049] Cu 2+ Ion concentration: 50g / L;

[0050] H 2 SO 4 Concentration: 100g / L;

[0051] Curing liquid temperature: 50℃;

[0052] Solidification liquid flow rate: 10.0m 3 / h;

[0053] Curing current density: 4000A / m 2 ;

[0054] Processing time: 10s.

[0055] Furthermore, the specific parameters of the S3.1 stage are as follows:

[0056] Zn 2+ Concentration: 0.5g / L;

[0057] K 4 P 2 O 7 Concentration: 45g / L;

[0058] pH: 11;

[0059] Current density: 45A / m 2 ;

[0060] Electrolyte temperature: 35°C;

[0061] Processing time: 10s;

[0062] The specific parameters of S3.2 are as follows:

[0063] Cr(VI) concentration: 0.5 g / L;

[0064] pH: 12;

[0065] Current density: 75A / m 2 ;

[0066] Electrolyte temperature: 30°C;

[0067] Processing time: 10s.

[0068] Furthermore, the parameters in the process of constructing the chemical bonding layer in S4 are as follows:

[0069] Silane liquid temperature: 30°C;

[0070] Silane liquid flow rate: 4.0m 3 / h;

[0071] Oven temperature: 180℃.

[0072] Furthermore, the ultra-low profile HVLP electrolytic copper foil is used to prepare a copper-clad laminate with a semi-cured ultra-low dielectric loss constant through hot pressing, and the copper-clad laminate is used to process a high-frequency printed circuit board PCB.

[0073] The beneficial effects of the present invention are as follows:

[0074] 1. The invention method produces ultra-low profile HVLP electrolytic copper foil by additive-assisted electrochemical deposition of ultra-low profile raw foil, additive-assisted fine roughening treatment, zero-content ferromagnetic functional layer construction and chemical bonding layer construction; and prepares a copper clad laminate CCL by hot pressing the ultra-low profile HVLP electrolytic copper foil and a semi-cured material with ultra-low dielectric loss constant; and further processes the copper clad laminate into a high-frequency printed circuit board PCB.

[0075] The HVLP copper foil produced by this technology has the following typical characteristics:

[0076] (1) Ultra-low surface profile. The line roughness Rz of the finished foil rough surface measured by laser confocal microscopy is between 1.0-1.5μm, Rz (JIS) is between 0.8-1.2μm, surface roughness Sz is between 2.1-3.0μm, interface expansion area ratio Sdr is between 5%-10%, and surface area ratio is between 1.10-1.15.

[0077] (2) Fine roughened structure, with the size of the roughened particles ranging from 350-700 nm and an average size of about 500 nm;

[0078] (3) Special morphology of coarsened tissue. The coarsened particles are stacked layer by layer from bottom to top to form a bamboo shoot-like structure with a height of 0.8-2.1 μm. There are obvious gaps between adjacent coarsened tissues. The valley empty volume Vvp is between 0.05-0.08 μm measured by laser confocal microscopy. 3 / μm 2 The nucleus void volume Vmp is between 0.27-0.74 μm 3 / μm 2 The existence of gaps between adjacent roughened structures is conducive to the penetration of resin during hot pressing and improves the bonding strength between copper foil and substrate;

[0079] (4) Contains no ferromagnetic metal content. The content of ferromagnetic metal elements such as NiCo in the surface treatment functional layer is 0 mg / m 2 , fundamentally eliminating the adverse effects of ferromagnetic metals on signal transmission;

[0080] (5) Stable anti-peel performance. The peel strength of the copper clad laminate obtained by laminating the 18μm finished foil with RogersRO4450F hydrocarbon resin (PCH) prepreg is between 3.0-4.3lb / in.

[0081] (6) Excellent signal integrity. The printed circuit board made of the ultra-low profile electrolytic copper foil produced by the present invention exhibits excellent signal transmission performance. In a microstrip line with a characteristic impedance of 50Ω, when the signal frequency is 16GHz, the insertion loss of the circuit board is between -0.64 and -0.85dB / in.

[0082] 2. The surface roughness of the HVLP electrolytic copper foil product produced by the present invention and 2023100730323 "A method for producing ultra-low profile copper foil for high-frequency and high-speed PCB" is comparable, so when processing copper clad laminate CCL products, the bonding strength between the electrolytic copper foil and the resin substrate is also sufficient. And because the product does not contain ferromagnetic metal content, as a raw material for PCB products, it fundamentally eliminates the adverse effects of ferromagnetic metal on signal transmission and ensures signal integrity.

[0083] Compared with the original product, the insertion loss in each frequency band is greatly reduced, achieving excellent performance of -0.32dB / in at 4GHz, -0.39dB / in at 8GHz, -0.48dB / in at 12.89GHz, and -0.64dB / in at 16GHz. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1The microscopic morphology of the HVLP finished foil produced in Example 1 (a) 8000 times; (b) 2000 times;

[0085] Figure 2 Microscopic morphology of the VLP finished foil produced in Comparative Example 1 (a) 8000 times; (b) 2000 times;

[0086] Figure 3 The microscopic morphology and particle size of the finished foil cross section of Example 1;

[0087] Figure 4 The pole figure, inverse pole figure and grain size distribution diagram of the sample in Example 1;

[0088] Figure 5 Laser confocal images of HVLP finished foils produced for different examples: (a) Example-1; (b) Comparative Example-1. DETAILED DESCRIPTION

[0089] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0090] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed but is merely representative of selected embodiments of the present invention.

[0091] Example 1

[0092] A production method of ultra-low profile HVLP electrolytic copper foil and its use, the method is divided into the following steps:

[0093] S1, additive-assisted electrochemical deposition of ultra-low profile green foil;

[0094] Additives with brightening, leveling and wetting effects are introduced into the acidic copper sulfate solution, and electrochemically deposited on the roller surface of the titanium cathode under the action of direct current to generate a raw foil with an ultra-low profile rough surface;

[0095] In this embodiment, the electrolytically generated ultra-low profile electrolytic green foil has a thickness of 18 μm, a smooth surface roughness Rz ≤ 1.0 μm, and a matte surface roughness Rz ≤ 1.0 μm. The parameters in the electrochemical deposition process of the green foil are as follows:

[0096] Cu 2+ Concentration: 80g / L;

[0097] H 2 SO 4 Concentration: 200g / L;

[0098] SPS concentration: 5ppm;

[0099] Collagen (Mw2500-3500) concentration: 10ppm;

[0100] PEG-2000 concentration: 15ppm;

[0101] Cl - Concentration: 15ppm;

[0102] Electrolyte temperature: 55°C;

[0103] Electrolyte flow rate: 40m 3 / h;

[0104] Current density: 80A / dm 2 .

[0105] S2, additive-assisted electrochemical micro-roughening treatment and curing;

[0106] The rough surface of the ultra-low profile raw foil generated in S1 is selected as the treatment surface. After the unwinding end is unwound, the copper foil is run into an electrolytic tank containing additives for fine roughening treatment. The electrolytic copper foil after ultra-fine roughening treatment is washed with water, squeezed dry, and then transferred to a curing tank for curing treatment.

[0107] The specific parameters of S2.1 ultra-fine roughening process are as follows:

[0108] Cu 2+ Ion concentration: 15g / L;

[0109] H 2 SO 4 Concentration: 150g / L;

[0110] Potassium tungstate phosphate concentration: 30ppm;

[0111] Electrolyte temperature: 30°C;

[0112] Roughening liquid flow rate: 10.0m 3 / h;

[0113] Average current density: 2500A / m 2 ;

[0114] Processing time: 10s.

[0115] The specific parameters of the S2.2 curing stage are as follows:

[0116] Cu 2+ Ion concentration: 50g / L;

[0117] H 2 SO 4 Concentration: 100g / L;

[0118] Curing liquid temperature: 50℃;

[0119] Solidification liquid flow rate: 10.0m 3 / h;

[0120] Curing current density: 4000A / m 2 ;

[0121] Processing time: 10s.

[0122] S3, construction of zero-content ferromagnetic functional layer;

[0123] In order to improve the anti-oxidation performance of electrolytic copper foil in the downstream processing, it is necessary to passivate the smooth and rough surfaces of the electrolytic copper foil to construct a zero-content ferromagnetic functional layer. This includes: depositing a zinc-containing barrier layer on the smooth and rough surfaces of the finely roughened copper foil in sequence through an electrochemical deposition process to improve the high-temperature anti-oxidation performance of the copper foil; and at the same time, electro-depositing a chromium-containing functional layer to improve the weather resistance of the copper foil at room temperature.

[0124] S3.1 Double-sided electrodeposition of zinc-containing barrier layer;

[0125] Zn 2+ Concentration: 0.5g / L;

[0126] K 4 P 2 O 7 Concentration: 45g / L;

[0127] pH: 11;

[0128] Current density: 45A / m 2 ;

[0129] Electrolyte temperature: 35°C;

[0130] Processing time: 10s.

[0131] S3.2 Double-sided electrodeposition of chromium-containing passivation layer;

[0132] Cr(VI) concentration: 0.5 g / L;

[0133] pH: 12;

[0134] Current density: 75A / m 2 ;

[0135] Electrolyte temperature: 30°C;

[0136] Processing time: 10s.

[0137] S4, chemical bonding layer adaptation and construction;

[0138] A chemical bonding layer is constructed on the matte surface of the ultra-low profile electrolytic copper foil to enhance the chemical bonding force between the matte surface of the HVLP copper foil and the resin sheet. According to the different functional groups of the downstream resin system, a silane coupling agent that matches the resin functional group is selected in a targeted manner. The copper foil after passivation treatment is run to the silane coupling agent treatment tank, and a chemical bonding layer is applied to the matte surface after roughening and passivation treatment by roller coating.

[0139] The parameters in the process of building the chemical bonding layer are as follows:

[0140] KBM-903 silane coupling agent concentration: 0.5wt%;

[0141] Silane liquid temperature: 30°C;

[0142] Silane liquid flow rate: 4.0m 3 / h;

[0143] Oven temperature: 180℃.

[0144] The product of the above steps is an ultra-low profile HVLP electrolytic copper foil that can be used to produce printed circuit boards.

[0145] The ultra-low profile HVLP electrolytic copper foil produced by the above method and the semi-cured copper foil with ultra-low dielectric loss constant are prepared by hot pressing to obtain a copper clad laminate CCL, which is further processed into a high-frequency printed circuit board PCB.

[0146] S5, thermal pressing of copper clad laminate;

[0147] First, referring to the "sandwich" structure, a semi-cured sheet of a specific resin system is selected and hot-pressed with the ultra-low profile HVLP electrolytic copper foil produced in the above steps to prepare a copper clad laminate.

[0148] The copper foil and the prepreg are laminated and heat pressed (4 prepregs are placed between the upper and lower copper foils).

[0149] The parameters during the thermal pressing process are as follows:

[0150] Prepreg model: RO4450F;

[0151] Pressing temperature: 240℃;

[0152] Insulation time: 140min;

[0153] Pressure per unit area: 30kgf / m 2 .

[0154] The above thermal pressing generates a copper clad laminate (CCL).

[0155] S6, printed circuit board PCB test;

[0156] The copper clad laminate (CCL) products in S5 are processed to generate high-frequency printed circuit boards (PCB).

[0157] S7, performance test;

[0158] S7.1. Perform performance test on the ultra-low profile HVLP electrolytic copper foil product 1 in S4.

[0159] S7.2. Perform a peel strength test on the copper clad laminate CCL product 1 in S5.

[0160] First, use a cutter to cut the hot-pressed copper clad laminate into strips; then use a utility knife to peel off the copper foil on one side of the copper clad laminate, and fix the peeled copper foil on one end of the weight; finally, the peel strength of the copper foil is tested on the peel strength tester by moving the weight.

[0161] The parameters of the peel strength test in this embodiment are as follows:

[0162] Spline width: 3.175mm;

[0163] Stripping length: 1cm;

[0164] Peeling angle: 90°;

[0165] Peeling speed: 50mm / min;

[0166] Number of tests per sample: 3 times.

[0167] S7.3, performing a signal transmission performance test on the printed high-frequency circuit board PCB product 1 in S6;

[0168] In the evaluation of transmission characteristics, the insertion loss of the PCB board at 4 GHz, 8 GHz, 12.89 GHz and 16 GHz was measured by a vector network analyzer VNA using a stripline resonator method suitable for measuring a bandwidth of 1-16 GHz.

[0169] Each sample is tested 5 times, and then the average value of the 5 tests is taken as the final test result of the sample. The greater the insertion loss of the board, the greater the negative absolute value.

[0170] In this embodiment, the parameters of the signal transmission performance test process are as follows:

[0171] Test strip structure: microstrip line;

[0172] Electrolyte thickness: 50 μm;

[0173] Conductor length: 1.0mm;

[0174] Conductor thickness: 18μm;

[0175] Conductor circuit width: 120μm;

[0176] Characteristic impedance: 50Ω.

[0177] S7.4. Summary of test results;

[0178] The test results in this embodiment are as follows:

[0179] The physical properties of the ultra-low profile HVLP electrolytic copper foil in S4 are:

[0180] The average size of the coarsened particles is about 500nm. The roughness of the rough surface measured by laser confocal microscopy is Rz 1.0μm, Rz (JIS) is 0.8μm, the surface roughness Sz is 2.1μm, the interface expansion area ratio Sdr is 5.0%, and the valley area void volume Vvp is 0.08μm. 3 / μm 2 The core area void volume Vmp is 0.27 μm 3 / μm 2 , the surface area ratio is 1.10.

[0181] The zinc electroplating amount on the treated surface is 15mg / m 2 , the amount of Cr deposited is 1.8 mg / m 2 .

[0182] The peel strength of the copper clad laminate CCL in S5 is 0.75N / mm and 4.3lb / in.

[0183] The insertion loss of the high-frequency printed circuit board PCB in S6 is -0.32dB / in at a frequency of 4GHz, -0.39dB / in at a frequency of 8GHz, -0.48dB / in at a frequency of 12.89GHz, and -0.64dB / in at a frequency of 16GHz.

[0184] Example 2

[0185] The difference between this comparative example and Example 1 is that:

[0186] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0187] MPS concentration: 10ppm; gelatin concentration: 15ppm; PPG-2000 concentration: 25ppm.

[0188] (2) The concentration of silane coupling agent during the construction of the chemical bonding layer was adjusted: the concentration of KBM-903 was increased from 0.5wt% to 1.0wt%.

[0189] The ultra-low profile HVLP electrolytic copper foil product 2, copper clad laminate CCL product 2, and high-frequency printed circuit board PCB product 2 in this embodiment were tested, and the results are as follows:

[0190] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 2 is about 550nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.2μm, Rz (JIS) is 0.98μm, the surface roughness Sz is 2.4μm, the interface expansion area ratio Sdr is 6.9%, and the valley area void volume Vvp is 0.06μm 3 / μm 2 , the core area void volume Vmp is 0.34μm 3 / μm 2 , the surface area ratio is 1.12.

[0191] The zinc electroplating amount on the treated surface is 13 mg / m 2 , the amount of Cr deposited is 1.6 mg / m 2 .

[0192] The peel strength of copper clad laminate CCL product 2 is 0.70 N / mm and 4.0 lb / in.

[0193] The insertion loss of the high-frequency printed circuit board PCB product 2 is -0.39dB / in at a frequency of 4GHz, -0.45dB / in at a frequency of 8GHz, -0.56dB / in at a frequency of 12.89GHz, and -0.72dB / in at a frequency of 16GHz.

[0194] Example 3

[0195] The difference between this comparative example and Example 1 is that:

[0196] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0197] ALS concentration: 10ppm; HEC concentration: 20ppm; PEG-1000 concentration: 10ppm.

[0198] (2) The additives used in the fine roughening process were adjusted: 30 ppm of potassium tungstate phosphate was replaced with 15 ppm of sodium molybdosilicate.

[0199] (3) The type and concentration of the silane coupling agent during the construction of the chemical bonding layer were adjusted from 0.5wt% of KBM-903 to 0.1wt% of KBM-503.

[0200] The ultra-low profile HVLP electrolytic copper foil product 3, copper clad laminate CCL product 3, and high-frequency printed circuit board PCB product 3 in this embodiment were tested, and the results are as follows:

[0201] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 3 is about 550nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.2μm, Rz (JIS) is 1.0μm, the surface roughness Sz is 2.7μm, the interface expansion area ratio Sdr is 8.8%, and the valley area void volume Vvp is 0.06μm 3 / μm 2 , the core area void volume Vmp is 0.38μm 3 / μm 2 , the surface area ratio is 1.12.

[0202] The zinc electroplating amount on the treated surface is 15mg / m 2 , the amount of Cr deposited is 1.6 mg / m 2 .

[0203] The peel strength of copper clad laminate CCL product 3 is 0.67N / mm and 3.8lb / in.

[0204] The insertion loss of the high-frequency printed circuit board PCB product 3 is -0.41dB / in at a frequency of 4GHz, -0.47dB / in at a frequency of 8GHz, -0.59dB / in at a frequency of 12.89GHz, and -0.75dB / in at a frequency of 16GHz.

[0205] Example 4

[0206] The difference between this comparative example and Example 1 is that:

[0207] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0208] Thiourea concentration: 5ppm; HEC concentration: 15ppm; PPG-1000 concentration: 20ppm.

[0209] (2) The additives used in the fine roughening process were adjusted: 30 ppm of potassium tungstate phosphate was replaced with 5 ppm of sodium phosphomolybdate.

[0210] (3) The type of silane coupling agent used in the chemical bonding layer construction process was adjusted from KBM-903 to 0.5wt% KBM-802.

[0211] The ultra-low profile HVLP electrolytic copper foil product 4, the copper clad laminate CCL product 4, and the high-frequency printed circuit board PCB product 4 in this embodiment were tested, and the results are as follows:

[0212] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 3 is about 600nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.3μm, Rz (JIS) is 1.1μm, the surface roughness Sz is 2.8μm, the interface expansion area ratio Sdr is 9.3%, and the valley area void volume Vvp is 0.07μm 3 / μm 2 , the core area void volume Vmp is 0.42μm 3 / μm 2 , the surface area ratio is 1.12.

[0213] The zinc deposition amount on the treated surface is 14 mg / m 2 , the amount of Cr deposited is 1.7 mg / m 2 .

[0214] The peel strength of copper clad laminate CCL product 4 is 0.60 N / mm and 3.4 lb / in.

[0215] The insertion loss of the high-frequency printed circuit board PCB product 4 is -0.43dB / in at a frequency of 4GHz, -0.50dB / in at a frequency of 8GHz, -0.63dB / in at a frequency of 12.89GHz, and -0.81dB / in at a frequency of 16GHz.

[0216] Example 5

[0217] The difference between this comparative example and Example 1 is that:

[0218] (1) The additives used in the micro-roughening process have been adjusted:

[0219] The 30 ppm potassium tungstate phosphate was replaced with 25 ppm sodium molybdenum cobaltate.

[0220] (2) The type and concentration of silane coupling agent in the process of building the chemical bonding layer were adjusted from 0.5wt% KBM-903 to 0.1wt% KBM-1003.

[0221] The ultra-low profile HVLP electrolytic copper foil product 5, the copper clad laminate CCL product 5, and the high-frequency printed circuit board PCB product 5 in this embodiment were tested, and the results are as follows:

[0222] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 5 is about 650nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.5μm, Rz (JIS) is 1.2μm, the surface roughness Sz is 3.0μm, the interface expansion area ratio Sdr is 10%, and the valley area void volume Vvp is 0.07μm 3 / μm 2 , the core area void volume Vmp is 0.48 μm 3 / μm 2 , the surface area ratio is 1.13.

[0223] The zinc electroplating amount on the treated surface is 16 mg / m 2 , the amount of Cr deposited is 2.0 mg / m 2 .

[0224] The peel strength of copper clad laminate CCL product 5 is 0.53 N / mm and 3.0 lb / in.

[0225] The insertion loss of the high-frequency printed circuit board PCB product 5 is -0.60dB / in at a frequency of 4GHz, -0.51dB / in at a frequency of 8GHz, -0.66dB / in at a frequency of 12.89GHz, and -0.78dB / in at a frequency of 16GHz.

[0226] Example 6

[0227] The difference between this comparative example and Example 1 is that:

[0228] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0229] MPS concentration: 10ppm; gelatin concentration: 15ppm; PPG-2000 concentration: 25ppm.

[0230] (2) The additives used in the fine roughening process were adjusted: 30 ppm of potassium tungstate phosphate was replaced with 10 ppm of sodium thiomolybdate.

[0231] (3) The concentration of the silane coupling agent type during the construction of the chemical bonding layer was adjusted from 0.5wt% of KBM-903 to 1.0wt% of KBM-503.

[0232] The ultra-low profile HVLP electrolytic copper foil product 6, the copper clad laminate CCL product 6, and the high-frequency printed circuit board PCB product 6 in this embodiment were tested, and the results are as follows:

[0233] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 6 is about 600nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.4μm, Rz (JIS) is 1.1μm, the surface roughness Sz is 2.5μm, the interface expansion area ratio Sdr is 8.3%, and the valley area void volume Vvp is 0.06μm 3 / μm 2 , the core area void volume Vmp is 0.45 μm 3 / μm 2 , the surface area ratio is 1.12.

[0234] The zinc electroplating amount on the treated surface is 15mg / m 2 , the amount of Cr deposited is 1.6 mg / m 2 .

[0235] The peel strength of copper clad laminate CCL product 6 is 0.63N / mm and 3.6lb / in.

[0236] The insertion loss of the high-frequency printed circuit board PCB product 6 is -0.45dB / in at a frequency of 4GHz, -0.47dB / in at a frequency of 8GHz, -0.59dB / in at a frequency of 12.89GHz, and -0.75dB / in at a frequency of 16GHz.

[0237] Example 7

[0238] The difference between this comparative example and Example 1 is that:

[0239] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0240] ALS concentration: 10ppm; HEC concentration: 20ppm; PEG-1000 concentration: 10ppm.

[0241] (2) The additive used in the micro-roughening process was adjusted: 30 ppm potassium tungstate phosphate was replaced with 20 ppm sodium sulfosilicate.

[0242] The ultra-low profile HVLP electrolytic copper foil product 7, the copper clad laminate CCL product 7, and the high-frequency printed circuit board PCB product 7 in this embodiment were tested, and the results are as follows:

[0243] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 7 is about 550nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.3μm, Rz (JIS) is 1.0μm, the surface roughness Sz is 2.3μm, the interface expansion area ratio Sdr is 7.5%, and the valley area void volume Vvp is 0.07μm 3 / μm 2 , the core area void volume Vmp is 0.40 μm 3 / μm 2 , the surface area ratio is 1.12.

[0244] The zinc electroplating amount on the treated surface is 15mg / m 2 , the amount of Cr deposited is 1.6 mg / m 2 .

[0245] The peel strength of copper clad laminate CCL product 7 is 0.61 N / mm and 3.5 lb / in.

[0246] The insertion loss of the high-frequency printed circuit board PCB product 7 is -0.42dB / in at a frequency of 4GHz, -0.52dB / in at a frequency of 8GHz, -0.63dB / in at a frequency of 12.89GHz, and -0.75dB / in at a frequency of 16GHz.

[0247] Example 8

[0248] The difference between this comparative example and Example 1 is that:

[0249] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0250] Thiourea concentration: 5ppm; HEC concentration: 15ppm; PPG-1000 concentration: 20ppm.

[0251] (2) The concentration of additives used in the fine roughening process was adjusted: the concentration of potassium tungstate phosphate was adjusted from 30 ppm to 20 ppm.

[0252] (3) The type and concentration of the silane coupling agent during the construction of the chemical bonding layer were adjusted from 0.5 wt % of KBM-903 to 1.0 wt % of KBM-802.

[0253] The ultra-low profile HVLP electrolytic copper foil product 8, the copper clad laminate CCL product 8, and the high-frequency printed circuit board PCB product 8 in this embodiment were tested, and the results are as follows:

[0254] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 8 is about 500nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 1.0μm, Rz (JIS) is 0.9μm, the surface roughness Sz is 2.2μm, the interface expansion area ratio Sdr is 5.8%, and the valley area void volume Vvp is 0.06μm 3 / μm 2 , the core area void volume Vmp is 0.37μm 3 / μm 2 , the surface area ratio is 1.11.

[0255] The zinc deposition amount on the treated surface is 14 mg / m 2 , the amount of Cr deposited is 1.7 mg / m 2 .

[0256] The peel strength of copper clad laminate CCL product 8 is 0.67N / mm and 3.8lb / in.

[0257] The insertion loss of the high-frequency printed circuit board PCB product 8 is -0.38dB / in at a frequency of 4GHz, -0.42dB / in at a frequency of 8GHz, -0.54dB / in at a frequency of 12.89GHz, and -0.71dB / in at a frequency of 16GHz.

[0258] Comparative Example 1

[0259] The difference between this comparative example and Example 1 is that the process parameters in the roughening process are adjusted, and no additives are introduced into the roughening electrolyte.

[0260] Cu 2+ Ion concentration: 15g / L

[0261] H 2 SO 4 Concentration: 150g / L

[0262] Electrolyte temperature: 30°C

[0263] Roughening liquid flow rate: 5.0m 3 / h

[0264] Average current density: 2500A / m 2

[0265] Processing time: 10s

[0266] The ultra-low profile HVLP electrolytic copper foil product 9, copper clad laminate CCL product 9, and high-frequency printed circuit board PCB product 9 in this comparative example were tested, and the results are as follows:

[0267] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 9 is about 1200nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 2.5μm, Rz (JIS) is 2.2μm, the surface roughness Sz is 4.7μm, the interface expansion area ratio Sdr is 21%, and the valley area void volume Vvp is 0.08μm 3 / μm 2 , the core area void volume Vmp is 0.64μm 3 / μm 2 , the surface area ratio is 1.15.

[0268] The zinc electroplating amount on the treated surface is 11mg / m 2 , the amount of Cr deposited is 1.2 mg / m 2 .

[0269] The peel strength of copper clad laminate CCL product 9 is 0.44N / mm and 32.5lb / in.

[0270] The insertion loss of the high-frequency printed circuit board PCB product 9 is -0.83dB / in at a frequency of 4GHz, -0.89dB / in at a frequency of 8GHz, -1.05dB / in at a frequency of 12.89GHz, and -1.24dB / in at a frequency of 16GHz.

[0271] Comparative Example 2

[0272] The difference between this comparative example and Example 4 is that the difference between this comparative example and Example 1 is that:

[0273] (1) The additives used in the ultra-low profile electrolytic foil production process have been adjusted:

[0274] Thiourea concentration: 5ppm; HEC concentration: 15ppm; PPG-1000 concentration: 20ppm.

[0275] (2) No additives are used in the surface treatment roughening process.

[0276] The ultra-low profile HVLP electrolytic copper foil product 10, the copper clad laminate CCL product 10, and the high-frequency printed circuit board PCB product 10 in this embodiment were tested, and the results are as follows:

[0277] The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil product 10 is about 1000nm. The roughness of the rough surface line Rz measured by laser confocal microscopy is 2.8μm, Rz (JIS) is 2.6μm, the surface roughness Sz is 5.1μm, the interface expansion area ratio Sdr is 24%, and the valley area void volume Vvp is 0.08μm 3 / μm2 , the core area void volume Vmp is 0.74μm 3 / μm 2 , the surface area ratio is 1.115.

[0278] The zinc electroplating amount on the treated surface is 10mg / m 2 , the amount of Cr deposited is 1.0 mg / m 2 .

[0279] The peel strength of the copper clad laminate CCL product 10 is 0.40 N / mm and 2.3 lb / in.

[0280] The insertion loss of the high-frequency printed circuit board PCB product 10 is -1.01dB / in at a frequency of 4GHz, -1.08dB / in at a frequency of 8GHz, -1.15dB / in at a frequency of 12.89GHz, and -1.37dB / in at a frequency of 16GHz.

[0281] From the product test data of the above embodiments and comparative examples:

[0282] The product performance of Examples 1-8 is very stable. The average size of the coarsened particles of the ultra-low profile HVLP electrolytic copper foil products is concentrated in the range of 500-650 nm, the roughness of the matte line Rz is concentrated in the range of 1.0-1.5 μm, Rz (JIS) is concentrated in the range of 0.8-1.2 μm, the surface roughness Sz is concentrated in the range of 2.1-3.0 μm, and the interface expansion area ratio Sdr is concentrated in the range of 5.0-9.3%.

[0283] The zinc electroplating amount on the treated surface is concentrated in 13-16 mg / m 2 , the amount of Cr deposited is concentrated in the range of 1.6 to 2.0 mg / m 2 .

[0284] The peel strength of the copper clad laminate CCL product 10 is concentrated in the range of 0.53 to 0.75 N / mm and 3.0 to 4.0 lb / in.

[0285] The insertion loss of the high-frequency printed circuit board PCB product 10 is concentrated in the range of -0.32 to -0.60 dB / in at a frequency of 4 GHz, -0.39 to -0.65 dB / in at a frequency of 8 GHz, -0.48 to -0.72 dB / in at a frequency of 12.89 GHz, and -0.64 to -0.85 dB / in at a frequency of 16 GHz.

[0286] In comparison, the performance indicators of the comparative products are all poor: the roughness of the rough surface line Rz is higher than 2.5μm, Rz (JIS) is higher than 2.2μm, the surface roughness Sz is higher than 4.7μm, and the interface expansion area ratio Sdr is higher than 21%.

[0287] The zinc deposition amount on the treated surface is less than 11mg / m 2 ,Cr electrodeposition is less than 1.2mg / m 2 .

[0288] The peel strength of the copper clad laminate CCL product 10 is less than 0.44 N / mm and 2.5 lb / in.

[0289] The insertion loss of the high-frequency printed circuit board PCB product 10 is lower than -0.83dB / in at a frequency of 4GHz, lower than -0.89dB / in at a frequency of 8GHz, lower than -1.05dB / in at a frequency of 12.89GHz, and lower than -1.24dB / in at a frequency of 16GHz.

[0290] This means:

[0291] In the present invention, the introduction of additives into the roughening electrolyte and their types and addition amounts; the additives used in the ultra-low profile electrolytic foil production process and their addition amounts; the additives used in the surface treatment roughening process and their addition amounts are necessary and effective, and can greatly improve various performance indicators of the product.

[0292] In order to more intuitively reflect the implementation effect of the present invention, the above examples and control examples were analyzed, and the microscopic morphology and parameters of the products produced in the examples were analyzed and characterized by field emission scanning electron microscopy (FE-SEM Zeiss, Sigma300) and laser confocal microscopy (Olympus, OLS5100), respectively. Figure 1-5 , the analysis of the picture is as follows:

[0293] Figure 1 The SEM image of the finished foil after the additive was introduced during the roughening process of Example 1 is shown. From this figure, it can be observed that there are elongated roughened structures, and there are obvious gaps between adjacent roughened structures. The existence of gaps between the roughened structures provides space for the infiltration of glue during the hot pressing process, which is beneficial to improve the bonding strength between the HVLP copper foil and the plate.

[0294] Figure 2 Shown is a SEM image of the finished foil of Comparative Example 1, which did not introduce additives during the roughening process.

[0295] contrast Figure 1 and Figure 2 It can be clearly found that the introduction of additives affects the microstructure of the coarsened structure: without the introduction of additives, the coarsened structure presents an obvious spherical morphology and the particle size is relatively large.

[0296] In order to further observe the microscopic morphology of the coarsened structure after the introduction of the additive, the sample of Example 1 was ion milled and the morphology was observed using a high-resolution field emission scanning electron microscope. Figure 3 As shown:

[0297] from Figure 3 It can be observed that the coarsened structure is a bamboo shoot-like morphology formed by the accumulation of particles from bottom to top. The height of the coarsened structure is between 0.8-2.1μm, with an average height of about 1.8μm. The particle size is between 350-700nm, with an average particle size of about 500nm.

[0298] In order to further study the crystal characteristics of HVLP copper foil, the sample in Example 1 was subjected to electron backscatter diffraction EBSD analysis. Figure 4 As shown:

[0299] right Figure 4 The analysis of the EBSD image shown shows that the ultra-low profile green foil has a clear block crystal structure, which is significantly different from the columnar crystal structure of the conventional HTE copper foil. The blocks of different colors in the EBSD pattern indicate that the ultra-low profile green foil produced in the electrolytic foil production process is a polycrystalline structure. The results of the pole figure show that no obvious preferred orientation appears in the HVLP copper foil produced by this method. The laser confocal microscope uses a non-contact laser as a medium to analyze and characterize the surface morphology of the sample.

[0300] Figure 5 Shown are the laser confocal cloud images of Example 1 and Comparative Example 1.

[0301] The figure can be used to intuitively compare the roughness of different samples. In Example 1, the green color accounts for a relatively high proportion in the cloud map, while the red color accounts for a relatively high proportion in the cloud map of Comparative Example 1. Therefore, the roughness of the sample in Example 1 is lower than that of the sample in Comparative Example 1.

[0302] The data of the above embodiments and comparative examples, as well as the product morphology analysis, can all confirm that the surface roughness of the present invention meets the requirements for processing copper clad laminates, and the bonding strength between the electrolytic copper foil and the resin substrate is indeed sufficient when processing copper clad laminate CCL products. In addition, since the product does not contain ferromagnetic metal content, as a raw material for PCB products, the adverse effects of ferromagnetic metals on signal transmission are fundamentally eliminated, ensuring signal integrity.

Claims

1. A method for producing ultra-low profile HVLP electrolytic copper foil, Features :The method is divided into the following steps: S1, additive-assisted electrochemical deposition of ultra-low profile green foil; A brightener for refining grain size, a displacement agent for enhancing additive wetting in the titanium cathode, and a leveler for improving the uniformity of electrochemical deposition of copper foil are introduced into the acidic copper sulfate solution. Through the coordinated effect of the above three types of additives, a raw foil with an ultra-low profile rough surface is generated by electrochemical deposition on the roller surface of the titanium cathode under the action of direct current. The brightener is one or more of thiourea, sodium polydisulfide propane sulfonate (SPS), sodium 3-mercaptopropane sulfonate (MPS), and sodium allyl sulfonate (ALS), and the content of the brightener in the electrolyte is between 5-10ppm; The moving agent is one or more of polyethylene glycol (PEG) and polypropylene glycol (PPG), and the content of the moving agent in the electrolyte is between 10-20ppm; The leveling agent is gelatin, collagen or hydroxyethyl cellulose (HEC), and the content of the leveling agent in the electrolyte is between 10-20ppm; S2, additive-assisted electrochemical micro-roughening treatment and curing; The rough surface of the ultra-low profile raw foil generated in S1 is selected as the treatment surface, and after the unwinding end is unwound, the copper foil is run into an electrolytic tank containing an additive for fine roughening treatment, and the electrolytic copper foil after the ultra-fine roughening treatment is washed with water, squeezed dry, and then transferred to a curing tank for curing treatment; The additive used in the micro-roughening process is specifically one or more of potassium tungstate phosphate, sodium molybdosilicate, sodium molybdophosphate, sodium molybdocobaltate, sodium thiomolybdate, and sodium thiosilicate; the concentration of the additive in the roughening electrolyte is between 10-30ppm; S3, construction of zero-content ferromagnetic functional layer; In order to improve the anti-oxidation performance of electrolytic copper foil in the downstream processing, the smooth and rough surfaces of the electrolytic copper foil need to be passivated. This treatment process does not introduce non-copper metal elements containing ferromagnetism. The content of nickel and cobalt ferromagnetic components in the barrier layer is 0mg / m 2 , that is, constructing a zero-content ferromagnetic functional layer; S3.1 Double-sided electrodeposition of zinc-containing barrier layer; The zinc barrier layer is deposited on the smooth and matte surfaces of the finely roughened copper foil in sequence through an electrochemical deposition process, and the zinc content of the matte and smooth surfaces is strictly controlled to 15-30g / m 2 To improve the high temperature oxidation resistance of copper foil; S3.2 Double-sided electrodeposition of chromium-containing passivation layer; At the same time, a chromium-containing functional layer is electrodeposited to improve the weather resistance of the copper foil at room temperature; S4, chemical bonding layer adaptation and construction; A chemical bonding layer is constructed on the matte surface of the ultra-low profile electrolytic copper foil, and a silane coupling agent matching the resin functional group is selected in a targeted manner; the copper foil after passivation treatment is run into a silane coupling agent treatment tank, and a chemical bonding layer is applied to the matte surface after roughening and passivation treatment by roller coating; The product produced by the above process is HVLP ultra-low profile electrolytic copper foil.

2. A method for producing an ultra-low profile HVLP electrolytic copper foil as claimed in claim 1, Features :The silane coupling agent used in S4 is one of epoxy, amino, vinyl, acrylic, and mercapto silane coupling agents, and the silicon concentration is between 0.1-1.0wt%.

3. A method for producing an ultra-low profile HVLP electrolytic copper foil as claimed in claim 1 or 2, Features The parameters of the electrochemical deposition process of the raw foil in S1 are as follows: Cu 2+ Concentration: 80g / L; H 2 SO 4 Concentration: 200g / L; Cl - Concentration: 15ppm; Electrolyte temperature: 55°C; Electrolyte flow rate: 40m 3 / h; Current density: 80A / dm 2 ; S2 is divided into the following two steps: The specific parameters of S2.1 ultra-fine roughening process are as follows: Cu 2+ Ion concentration: 15g / L; H 2 SO 4 Concentration: 150g / L; Electrolyte temperature: 30°C; Roughening liquid flow rate: 10.0m 3 / h; Average current density: 2500A / m 2 ; Processing time: 10s; The specific parameters of the S2.2 curing stage are as follows: Cu 2+ Ion concentration: 50g / L; H 2 SO 4 Concentration: 100g / L; Curing liquid temperature: 50℃; Solidification liquid flow rate: 10.0m 3 / h; Curing current density: 4000A / m 2 ; Processing time: 10s.

4. A method for producing an ultra-low profile HVLP electrolytic copper foil as claimed in claim 3, Features :The specific parameters of S3.1 are as follows: Zn 2+ Concentration: 0.5g / L; K 4 P 2 O 7 Concentration: 45g / L; pH: 11; Current density: 45A / m 2 ; Electrolyte temperature: 35°C; Processing time: 10s; The specific parameters of S3.2 are as follows: Hexavalent chromium concentration: 0.5g / L; pH: 12; Current density: 75A / m 2 ; Electrolyte temperature: 30°C; Processing time: 10s.

5. A method for producing an ultra-low profile HVLP electrolytic copper foil as claimed in claim 4, Features The parameters in the process of constructing the chemical bonding layer in S4 are as follows: Silane liquid temperature: 30°C; Silane liquid flow rate: 4.0m 3 / h; Oven temperature: 180℃.

6. Use of the ultra-low profile HVLP electrolytic copper foil produced by the method according to any one of claims 1 to 5, Features The HVLP ultra-low profile electrolytic copper foil is used to prepare a copper-clad laminate by hot pressing with a semi-cured sheet with an ultra-low dielectric loss constant. The copper-clad laminate is used to process a high-frequency printed circuit board PCB.

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