阅读说明：本技术 一种电解铜箔用添加剂、超低峰值hvlp铜箔及其制备方法 (Additive for electrolytic copper foil, ultralow-peak-value HVLP copper foil and preparation method thereof ) 是由 林家宝 于 2019-12-02 设计创作，主要内容包括：本发明涉及电解铜箔技术领域,具体涉及一种电解铜箔用添加剂、超低峰值HVLP铜箔及其制备方法。所述添加剂包括酸铜强走位剂、四氢噻唑硫酮、聚乙烯亚胺烷基盐、聚二硫二丙烷磺酸钠、胶原蛋白、牛皮多肽中的至少四种和氯离子。本发明具有低粗糙度、机械性能优异、抗氧化效果好的优点。(The invention relates to the technical field of electrolytic copper foil, in particular to an additive for electrolytic copper foil, an ultralow peak value HVLP copper foil and a preparation method thereof. The additive comprises chloride ions and at least four of acid copper displacement agent, thiazolidine thione, polyethyleneimine alkyl salt, sodium polydithio-dipropyl sulfonate, collagen and cow leather polypeptide. The invention has the advantages of low roughness, excellent mechanical property and good oxidation resistance effect.)

1. An additive for electrolytic copper foil is characterized by comprising chloride ions and at least four of acid copper displacement agent, thiazolidinethione, polyethyleneimine alkyl salt, sodium polydithio-dipropyl sulfonate, collagen and cow leather polypeptide.

2. The additive as claimed in claim 1, wherein the acid copper delocalizing agent is an aliphatic amine ethoxylate sulfonate, and the molecular weight of the collagen is 3000-6000 daltons.

3. The additive according to claim 1, further comprising water, preferably, the content of the acid copper translocating agent is 0.005-0.02g/L, the content of the thiazolidinethione is 0.0004-0.001g/L, the content of the polyethyleneimine alkyl salt is 0.01-0.02g/L, the content of the sodium polydithio-dipropionate is 0.01-0.5g/L, the content of the collagen is 0.05-1.0g/L, the content of the cow hide polypeptide is 0.05-1.0g/L, and the content of the chloride ion is 10-20 ppm.

4. An ultra low peak HVLP copper foil made with the additive of any of claims 1-3.

5. A method of making the ultra low peak HVLP copper foil of claim 4, comprising the steps of:

(1) preparing an electrolyte: adding copper into a solution containing sulfuric acid to obtain an electrolyte;

(2) and (3) grinding the surface of the cathode roller: mechanically polishing and grinding the cathode roller;

(3) electroplating of the raw foil: adding the additive according to any one of claims 1 to 3 to the electrolyte and performing electrodeposition on a cathode roll to obtain a green foil;

(4) surface treatment: the raw foil is subjected to surface treatment by adopting a direct current electrodeposition process and is divided into 7 stages, namely an acid washing stage, a coarsening stage, a copper curing stage, a weak coarsening stage, an anti-oxidation stage, a passivation stage and a surfactant treatment stage.

6. The method according to claim 5, wherein the electrolyte in the step (1) has a copper content of 60 to 100g/L, a sulfuric acid content of 80 to 150g/L, a chloride ion content of 15 to 30ppm, and a temperature of 40 to 70 ℃.

7. The method according to claim 5, wherein the surface finish of the cathode roll after mechanical polishing in step (2) is less than or equal to 0.2 μm.

8. The production method according to claim 5, wherein the flow rate of the electrolyte during the electrodeposition in the step (3) is 50 to 80m³Current density 4500-²。

9. The method according to claim 5, wherein the surfactant in the step (4) is at least two selected from the group consisting of an epoxy silane, a vinyl silane, an amino silane, a ureido silane, and a mercapto silane.

10. Use of the additive according to any one of claims 1 to 3 or the ultra-low peak HVLP copper foil according to claim 4 or the ultra-low peak HVLP copper foil prepared by the preparation method according to any one of claims 5 to 9 in high frequency 5G circuit boards.

Technical Field

The invention relates to the technical field of electrolytic copper foil, in particular to an additive for electrolytic copper foil, an ultralow peak value HVLP copper foil and a preparation method thereof.

Background

At present, mobile communication technology and industry will advance to the development stage of the 5 th generation mobile communication (5G), and the 5G will meet the requirements of people on ultra-high data transmission rate, ultra-high mobility and the like, and millimeter wave frequency spectrum resources with larger bandwidth will be further opened in order to deal with mass and high-speed data transmission. With the increase of available frequencies in the future, the concept of high frequency PCB design is also changing, for example, high frequency PCBs are more and more shifted from single-sided and double-sided boards to multi-layered boards, and a complex metallized via structure (any interlayer interconnection) is replacing a simple metal via structure or a non-metal via structure.

According to the microwave technology theory for the division of the transmission line, a TEM (trans electric) transmission line and a waveguide can be used as carriers for high frequency signal transmission, and a microstrip line (Micro-Strip) in the TEM transmission line structure, a Strip line (Strip-line) and a Substrate integrated waveguide (SWI) in the waveguide structure are all applied in the high frequency PCB design.

In the high-frequency PCB design, in terms of the relationship between the attenuation of the high-frequency signal in the unused transmission line and the copper foil, the influence of the copper foil on the microstrip line and the strip line is much larger than that on the SIW structure (or the contribution rate of the loss of the medium in the SIW structure to the insertion loss of the whole transmission line is larger), in the microstrip line or strip line design, when the high-frequency signal is transmitted in the wire, most of the electromagnetic wave energy is bound in the interlayer between the wire and the shielding layer, and the skin effect causes the transmission of the high-frequency signal to be concentrated on the thin layer on the surface of the wire, and the closer to the surface of the wire, the higher the alternating current density is. For the microstrip line, the roughness of the copper foil which tends to be contacted with the medium has a very important influence on the insertion loss of the product. The roughness of the copper foil refers to the roughness of the contact surface (the top and the side wall of the line) of the copper foil and the substrate medium after the PCB process, for example, the roughness of the surface (the top and the side wall of the line) of the copper foil caused by the inner layer roughening before etching or laminating in the strip line design.

The contour dimension of the surface of the copper foil becomes an important investigation factor of PCB processing, and the low-contour copper foil, namely the ultra-low peak HVLP copper foil, becomes the trend of PCB development in the future. The surface roughness of the copper foil is one of the key factors that affect the etching effect and determine the fineness of the etched circuit. From the perspective of signal transmission, the copper foil with smooth surface is more suitable for high-frequency and high-speed board application. The ultra-low peak HVLP copper foil is developed to balance the performance requirements of copper foil etching performance and adhesive force. During the storage and transportation of the copper foil, a copper oxide layer is inevitably formed on the surface of the copper foil, and the copper foil needs to be cleaned by acid washing before treatment. And chemically treating the copper foil after acid washing in special roughening treatment liquid to form nano nodular particles on the surface of the copper foil. And continuously carrying out curing treatment on the copper foil to form a uniform compact covering layer on the surface of the copper foil. Because the nano-nodular particles have large specific surface area, the anchoring effect can strengthen the combining capability between the copper foil and the prepreg.

At present, 5G communication is rapidly developed, and will enter into commercial operation, and the electrolytic copper foil required by applying CCL process together with 5G will become a key point of market competition. With the popularization of mobile terminals, data communication has been accelerated. At the same time, there is an increasing demand for reducing the transmission loss of the copper foil, which is a conductor of a circuit board, and particularly, the current in a high frequency range tends to concentrate on the surface of the conductor, and the surface irregularities have a great influence on the transmission loss. The ultralow-peak electrolytic copper foil for the high-frequency 5G circuit board adopts a special surface treatment technology to control the surface roughness to the limit, and the micro coarsening particles are controlled to be between 100 and 800nm, so that the copper foil capable of reducing the transmission loss in a high-frequency range is developed, and support is provided for improving the performance and stability of high-speed data communication. The appearance is consistent with the existing copper foil, and the peak value Rz is generally required to be less than or equal to 3.0 μm.

Chinese patent application CN108677222A discloses an electrolyte for preparing a lithium electrolytic copper foil and a production process, wherein the electrolyte comprises a main electrolyte and an additive, the main electrolyte is a copper sulfate-sulfuric acid aqueous solution, the additive comprises chloride ions, an agent A, an agent B and an agent C, the agent A is alkyl sulfonate containing low-valent sulfur, the agent B is a nitrogen-containing natural high molecular compound or a nitrogen-containing synthetic high molecular compound, and the agent C is a cryptate compound. The current density adopted by the production process is 30-85A/dm². The electrolyte adopts specific additives and the proportion is optimized, so that the growth of crystal grains can be effectively controlled, a compact copper foil is obtained, and the copper foil prepared by the electrolyte and the production process has high tensile strength and high elongation; the electrolyte and the production process are particularly suitable for producing 6-micron ultrathin copper foil, and the prepared copper foil is excellent in mechanical property, stable and easy to control in color and brightness. However, the mechanical properties of the copper foil need to be improved, and the transmission loss after the copper foil is applied to the PCB needs to be further reduced.

Therefore, it is very necessary to develop an additive for electrolytic copper foil, an ultra low peak HVLP copper foil and a method for preparing the same, which can solve the above-mentioned technical problems.

Disclosure of Invention

The present invention has been made to overcome the disadvantages of the prior art and provides an additive for an electrolytic copper foil, an ultra low peak HVLP copper foil having an equiaxed crystalline layer characteristic and being planar, and a method for preparing the same. The crystalline structure can prevent the sliding among metal crystal grains, and has larger force to resist the deformation caused by the influence of external conditions. The surface of the copper foil has low profile and low signal loss, and the normal temperature and high temperature tensile strength and the elongation are superior to those of the common electrolytic copper foil. Compared with the common copper foil, the ultra-low peak value HVLP copper foil is smooth and fine in roughened surface. Residual copper powder (copper powder transfer phenomenon) can not be generated on the connection interface of the copper foil and the substrate after etching, the surface resistance and the interlayer resistance characteristic of the PCB are improved, and the reliability of the dielectric property is improved. The ultra-low peak HVLP copper foil of the present invention has high thermal stability and does not cause copper recrystallization from multiple lamination on thin substrates. The time for etching the graphic circuit is shortened compared with the common electrolytic copper foil, the side etching phenomenon is reduced, white spots after etching are reduced, the method is suitable for manufacturing 5G fine circuits, has high hardness, improves and improves the drilling performance of a multilayer board, and is also more suitable for laser drilling. The surface of the ultra-low peak HVLP copper foil is relatively flat after a multi-layer board is pressed and formed, and is suitable for manufacturing fine circuits. The ultralow-peak HVLP copper foil is uniform in thickness, small in signal transmission delay after being manufactured into a PCB, excellent in characteristic impedance control, free of noise among lines and between layers and the like.

The invention is realized by the following technical scheme:

an additive for electrolytic copper foil comprises chloride ions and at least four of acid copper displacement agent, thiazolidinethione, polyethyleneimine alkyl salt, sodium polydithio-dipropyl sulfonate, collagen and cow leather polypeptide.

Preferably, the acid copper delocalizing agent is fatty amine ethoxy sulfonate.

Preferably, the molecular weight of the collagen is 3000-6000 daltons, i.e. the collagen is a low molecular weight collagen.

Preferably, the additive further comprises water.

More preferably, the content of the acid copper strong displacement agent is 0.005-0.02 g/L.

More preferably, the content of the thiazolidinethione is 0.0004 to 0.001 g/L.

More preferably, the content of the polyethyleneimine alkyl salt is 0.01 to 0.02 g/L.

More preferably, the sodium polydithio-dipropyl sulfonate is contained in an amount of 0.01 to 0.5 g/L.

More preferably, the content of the collagen is 0.05-1.0 g/L.

More preferably, the content of the cow leather polypeptide is 0.05-1.0 g/L.

More preferably, the content of the chloride ion is 10 to 20 ppm.

More preferably, the additive comprises the following components: 0.005-0.02g/L, PN g of AESS acid copper strong displacement agent, 0.01-0.02g/L, SP g/L of sodium polydithio-dipropyl sulfonate, 0.01-0.5g/L of small molecular weight collagen and 10-20ppm of chloride ions.

More preferably, the additive comprises the following components: 0.005g/L, PN g of AESS acid copper strong displacement agent, 0.015g/L, SP g/0.1 g/L of sodium polydithio-dipropyl sulfonate, 1.0g/L of small molecular weight collagen and 15ppm of chloride ions.

More preferably, the additive comprises the following components: PN polyethyleneimine alkyl salt 0.01-0.02g/L, SP sodium polydithio-dipropyl sulfonate 0.01-0.5g/L, H1 tetrahydrothiazole thione 0.0004-0.001g/L, small molecular weight collagen 0.05-1.0g/L and chloride ion 10-20 ppm.

More preferably, the additive comprises the following components: PN polyethyleneimine alkyl salt 0.015g/L, SP sodium polydithio-dipropyl sulfonate 0.1g/L, H1 tetrahydrothiazole thione 0.0005g/L, small molecular weight collagen 1.0g/L, and chloride ion 15 ppm.

More preferably, the additive comprises the following components: 0.005-0.02g/L, PN g of AESS acid copper strong displacement agent, 0.01-0.02g/L, SP g/L of sodium polydithio-dipropyl sulfonate, 0.01-0.5g/L of cow leather polypeptide and 10-20ppm of chloride ions.

More preferably, the additive comprises the following components: 0.005g/L, PN g of AESS acid copper strong displacement agent, 0.01g/L, SP g/0.2 g/L of sodium polydithio-dipropyl sulfonate, 0.2g/L of cow leather polypeptide and 15ppm of chloride ions.

More preferably, the additive comprises the following components: PN polyethyleneimine alkyl salt 0.01-0.02g/L, SP sodium polydithio-dipropyl sulfonate 0.01-0.5g/L, H1 tetrahydrothiazole thione 0.0004-0.001g/L, cow leather polypeptide 0.05-1.0g/L and chloride ion 10-20 ppm.

More preferably, the additive comprises the following components: PN polyethyleneimine alkyl salt 0.01g/L, SP sodium polydithio-dipropyl sulfonate 0.05g/L, H1 tetrahydrothiazolethione 0.001g/L, cow leather polypeptide 0.5g/L, and chloride ion 15 ppm.

The invention also relates to an ultralow-peak HVLP copper foil prepared by adopting the additive.

The roughness Rz of the rough surface of the ultra-low peak HVLP copper foil is less than or equal to 2 mu m, and the stripping strength is more than or equal to 1.3 kgf/cm.

The ultra-low peak HVLP copper foil has a thickness of 12-35 microns.

The invention also relates to a preparation method of the ultra-low peak HVLP copper foil, which comprises the following steps:

(1) preparing an electrolyte: adding copper into a solution containing sulfuric acid to obtain an electrolyte;

(2) and (3) grinding the surface of the cathode roller: mechanically polishing and grinding the cathode roller;

(3) electroplating of the raw foil: adding the additive according to any one of claims 1 to 3 to the electrolyte and performing electrodeposition on a cathode roll to obtain a green foil;

(4) surface treatment: the raw foil is subjected to surface treatment by adopting a direct current electrodeposition process and is divided into 7 stages, namely an acid washing stage, a coarsening stage, a copper curing stage, a weak coarsening stage, an anti-oxidation stage, a passivation stage and a surfactant treatment stage.

1 acid washing

The produced copper foil exists in a winding mode, in order to prevent the edge tearing phenomenon on a crude foil machine, crude foil rolls are thick in the middle and thin in two sides, the winding compactness degree of the thick middle part is high, the distance between the crude foils on the edge part is increased, a certain gap is formed, especially under certain humidity, the gap of the crude foil rolls can absorb a certain liquid layer, the smooth surface and the rough surface of the crude foil are connected, and conditions are created for corrosion of the crude foil. Therefore, the placed hair foil is easily oxidized. If the oxidized copper foil is directly roughened, the roughening strength is reduced, and the plating layer is peeled off, so that the treatment effect is not achieved. In addition, the acid washing and water washing effects of the rough foil before rolling are poor, and the rough foil often has certain impurities, and the impurities not only accelerate the oxidation of the rough foil, but also reduce the bonding strength of the rough layer and the rough foil in the subsequent process. Therefore, when the foil enters the roughening machine, the foil is first subjected to acid cleaning treatment to remove the oxidized layer and impurities adsorbed on the hair surface. The same electrolyte as used in the roughening stage was used for pickling, except that no current was passed.

2 roughening

In order to improve the peeling strength of the copper-clad plate, the roughness of the surface of the rough foil is insufficient, and the aim of coarsening is to improve the peak value of the rough foil so as to meet the requirement of a pressing plate on the peeling strength of the pressing plate. The electrolyte composition and process specification are shown in Table 1, wherein "-" indicates that the additive D is not used in the oxidation prevention stage, the additive D is a mixture of potassium pyrophosphate and sodium citrate, the concentration of the potassium pyrophosphate is 40 +/-3 g/L, the concentration of the sodium citrate is 20-30g/L, and the pH value is 10.3-11.3. The cell is shown in FIG. 1. As can be seen from the data in Table 1, Cu was used in the roughening stage²⁺Has very low content of (A) and high current density.

TABLE 1 surface treatment electrolyte composition

The cathode reaction of the electroplating process is not only Cu²⁺When the newly generated copper plating layer is oxidized into 'copper powder' (actually, copper oxide), the copper powder is attached to the rough surface of the copper foil to form a poor conductive part which is basically and uniformly distributed on the surface of the copper foil, so that local current density distribution on the rough surface is uneven, a peak-making effect is achieved, and the roughness of the rough surface is increased. The reaction equation is as follows:

anodic reaction 2H₂O-4e＝4H⁺+O₂↑ (1)

Cathodic reaction of Cu²⁺+2e＝Cu (2)

Total reaction 2Cu²⁺+2H₂O＝2Cu+4H⁺+O₂↑ (3)

When Cu²⁺When deficiency is present

Cu+O₂＝2CuO (4)

4Cu+O₂＝2Cu₂O (5)

Since the coating formed in this portion is a coating in which copper and its oxide are uniformly distributed, the peak position thereof has relatively poor bonding strength with the substrate and is relatively liable to be peeled off, and therefore, a curing treatment, that is, a sealing treatment as it is, is required.

In addition, the roughening current is an important factor influencing roughening, and excessive current can cause the problem of residual copper in the etching process after the pressing plate, which is mainly caused by the fact that the roughened peak value is high under the condition of high current. Therefore, the roughening current needs to be controlled to meet a certain requirement on peel strength during roughening and ensure that no residual copper is generated during etching.

3 curing

Since the plating layer produced in the roughening step is easy to fall off, a copper plating layer is added to reinforce the copper plating layer, namely, a sealing treatment, which is also called as solidification, and actually, a thin layer of copper is deposited on the rough surface of the copper foil to cover the copper powder, the electrolyte composition and the process specification of the copper foil are shown in a table 1, and the electrolytic cell is shown in a figure 1.

4 weak roughening

In order to increase the roughness of the rough surface of the copper foil after the sealing treatment and enable the rough surface to meet the requirement of a pressing plate, the rough surface of the copper foil is subjected to weak roughening treatment so as to further increase the peeling strength of the roughened copper foil, the composition and the process specification of the electrolyte are shown in a table 1, and an electrolytic bath is shown in a figure 1. For the relative coarsening, H in the weakly coarsened electrolyte₂SO₄、Cu²⁺The concentration is reduced, the current density of electroplating is greatly reduced, and therefore, the copper foil is deposited on the rough surfaceMainly copper and partly "copper powder", which only slightly increases the roughness, so called weak roughening. FIG. 2 shows the variation of the copper foil roughness peak in the course of roughening, curing and weak roughening.

5 Oxidation prevention treatment

The roughened surface of the copper foil is fresh, has high surface energy and high activity, is very easy to be oxidized in a high-temperature environment, and needs to be subjected to anti-oxidation treatment by galvanizing and chroming the copper foil, and the composition and the process specification of the electrolyte are shown in table 1.

Fig. 3 shows the layout of an oxidation-resistant electrolytic cell, wherein the anodes at two sides are zinc plates, and the anode plate in the middle is stainless steel.

The process adopts alkaline zincate zinc plating, and the mechanism is as follows:

Zn+2OH^-+2H₂O＝[Zn(OH)₄]^2-+H₂↑ (6)

Zn²⁺+4OH^-＝[Zn(OH)₄]^2-(7)

as can be seen from the data in Table 1, OH^-Is excessive, so that in the electrolyte, Zn is present²⁺Is very small, typically in the form of [ Zn (OH) ]]⁺、[Zn(OH)₃]^-、[Zn(OH)₄]^2-In the presence of a plasma [ Zn (OH) ]₄]^2-Most stable, mainly [ Zn (OH) during electroplating process₄]^2-Discharging:

cathodic reaction [ Zn (OH)₄]^2-+2e＝Zn+4OH^-(8)

Side reaction 2H₂O+2e＝H₂↑+2OH^-(9)

Anodic reaction Zn +4OH^--2e＝[Zn(OH)₄]^2-(10)

4OH^--4e＝2H₂O+O₂↑ (11)

In general, the zinc electrode is chemically soluble in addition to the electrochemical dissolution, [ Zn (OH) ]₄]^2-Is higher, the cathode reaction is enabledThe higher the anodic reaction rate, the greater the probability of reaction (11) occurring (particularly on stainless steel anode plates), producing OH^-The pH of the whole system is lowered by the consumption of potassium pyrophosphate, and therefore it is necessary to appropriately replenish potassium pyrophosphate. In addition, if the current density is too high, the dissolution rate of zinc is insufficient, and the cathode surface is caused to react (9), so that the coating is adversely affected, and the situation is avoided by adding zinc sulfate in the actual production.

In the electroplating process, potassium pyrophosphate is used as an important additive, and the action of the potassium pyrophosphate mainly comprises the following two aspects:

(1) during normal anodic dissolution galvanization, it is necessary to ensure a pH around 11, since the zinc deposition is mainly complex ions [ Zn (OH) ]₄]^2-Discharge, in which OH-originates from the hydrolysis of potassium pyrophosphate, has the following chemical equation:

P₂O₇ ^4-+H₂O＝HP₂P₇ ^3-+OH^-(12)

HP₂P₇ ^3-+H₂O＝H₂P₂O₇ ^2-+OH^-(13)

(2) the other auxiliary effect of the potassium pyrophosphate in the electrolytic process is to increase the total ion concentration of the electrolyte and be beneficial to the conductivity of the electrolyte, thereby reducing the bath pressure, reducing the self-heating of the electrolyte and keeping the normal temperature in the electrolytic process.

In addition, the temperature and current density of the plating solution also have some effect on the plating during the electroplating process. In the normal operating temperature range, as the temperature increases, the cathode current efficiency increases and the applied current density range shifts upward. However, the dispersing ability of the electrolyte is reduced, the dissolution speed of the zinc anode is increased, and the solution is unstable, so that the zinc anode is not suitable for working at an excessively high temperature. Alkaline galvanizing has a wide current density range, generally 1-5A/dm²In the meantime. It is desirable to maintain a higher current density when the composition and temperature of the electrolyte is constant. It can improve the dispersion ability of electrolyte to a certain extent, raise cathode polarization and is favourable for raising dispersion capacity of electrolyteAn excellent plating layer is obtained. The current density is too high, the coating is coarse and dull in crystallization, and the edge part has a risk of scorching.

6 passivation treatment

The purpose of chromium plating is to passivate the zinc coating, because the surface of the metal chromium is easy to generate a stable oxide layer, and the chromium coating has high hardness, the copper foil can be ensured not to be damaged in the process of transportation.

The process uses potassium dichromate which is firstly reacted with hydroxyl to convert into CrO after being added into electrolyte₄ ^2-The reaction is reversible, and the electrode reaction is as follows:

and (3) cathode reaction: cr (chromium) component₂O₇ ^2-+7H₂O+6e＝2Cr³⁺+14OH^-(14)

CrO₄ ^2-+4H₂O+3e＝Cr³⁺+8OH^-(15)

Side reaction: 2H₂O+2e＝H₂↑+2OH^-(16)

And (3) anode reaction: 12OH^－-12e＝3O₂↑+6H₂O (17)

Produced Cr³⁺Further reactions were carried out:

2Cr³⁺+6OH^-＝Cr₂O₃·3H₂O (18)

in addition, since zinc is dissolved under alkaline conditions, small amounts of zinc ions will also be present in the chromium bath and the following reactions will occur:

2Zn²⁺+2OH^-+CrO₄ ^2-＝Zn₂(OH)₂CrO₄(19)

Zn²⁺+2Cr³⁺+8OH^-＝4H₂O+Zn(CrO₂)₂(20)

7 surfactant treatment

Preferably, in the surfactant treatment stage, the surfactant is dissolved by water to form a surfactant aqueous solution, and the total mass fraction of the surfactant is 0.1-1%.

Preferably, the copper content of the electrolyte in the step (1) is 60-100g/L, the sulfuric acid content is 80-150g/L, the chloride ion content is 15-30g/L, and the temperature is 40-70 ℃.

Preferably, the surface finish of the cathode roller after mechanical polishing in the step (2) is less than or equal to 0.2 μm.

The mechanical polishing comprises an off-line mode and an on-line mode. The off-line polishing is carried out on a roller mill, the grinding material is an abrasive paper tape or a special grinding sheet, and the grinding material is ground to the other end from one end of the cathode roller in a spiral mode during polishing and then ground back. A water mill cathode roller belongs to off-line polishing. Table 2 shows the water mill cathode roll polishing process.

TABLE 2 polishing and grinding process for water mill cathode roll

The green foil produced after the water grinding of the cathode roller is enlarged by 1000 times under an electron microscope to observe the microscopic appearance of the smooth surface of the copper foil, shallow trench-shaped scraping traces are formed on the ground microscopic surface along the longitudinal direction, and the surface of the polished micro-light roller is in shallow pits in the current situation, so that the polished cathode roller is more uniform and softer, the surface smoothness can reach within 0.2 mu m, and the physical performance indexes of the produced copper foil between the longitudinal direction and the transverse direction are closer.

Preferably, the flow rate of the electrolyte in the electrodeposition process in the step (3) is 50-80m³Current density 4500-²The current intensity is 45000-50000A.

Preferably, the cathode roll running linear speed in step (3) is as shown in table 3.

TABLE 3 cathode roll running linear velocity of copper foil of different thickness under different current intensity

Cathode roller running linear speed m/min	12 micron copper foil	18 micron copper foil	35 micron copper foil
				45000A	6.70±0.20	4.65±0.20	2.43±0.20
50000A	7.46±0.20	5.19±0.20	2.70±0.20

When the additive is used, pure water with the temperature close to that of electrolyte is used for dissolving, the temperature is kept at the temperature close to that of the electrolyte, and the additive is circularly filtered by activated carbon from dissolving, storing to adding.

Preferably, the surfactant in step (4) is at least two of epoxy silane, vinyl silane, amino silane, ureido silane and mercapto silane.

The epoxy silane is one of (3-glycidoxypropyl) trimethoxy silane and (3-glycidoxypropyl) triethoxy silane.

The vinyl silane is one of vinyl trimethoxy silane and vinyl triethoxy silane.

The aminosilane is one of 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

The ureido silane is 3-ureido propyl triethoxy silane.

The mercaptosilane is 3-mercaptopropyltrimethoxysilane.

The invention also relates to the application of the additive or the ultra-low peak value HVLP copper foil prepared by the preparation method in a high-frequency 5G circuit board.

The invention has the beneficial effects that:

the invention adopts special additives, thereby solving the problem that the roughness of the copper foil produced under high current density is higher. Additives with different components play different roles in the electrodeposition process, such as increasing cathode polarization by chloride ions and inhibiting abnormal growth of metal, so as to improve the ductility, hardness and smoothness of the copper foil; at least four of acid copper strong displacement agent, thiazolidine thione, polyethyleneimine alkyl salt, sodium polydithio-dipropyl sulfonate, collagen and cow leather polypeptide are combined for refining grains, the shape of rough surface peaks and valleys of the copper foil is improved, the density of the copper foil is increased and the like.

The copper foil crystal particles prepared by the method are more uniform and finer, the roughness of the rough surface is reduced, the copper foil crystal particles have the characteristic of equiaxial crystal layers, are planar, and have high tensile and elongation properties. The copper foil is manufactured by using a novel additive, and various performances of the electrolytic copper foil are suitable for high-power circuit boards in the automobile industry, power grids, communication and the like. The electro-crystallization particles of the copper foil manufactured by the additive are more uniform and refined, and the copper foil has higher tensile and elongation performances and maintains certain peel strength.

The surface treatment process of the ultralow-peak HVLP copper foil post-treatment stage is characterized in that a direct-current deposition process is adopted, and the surface of the electrolytic copper foil is subjected to low-coarsening treatment by adopting different electrolyte combinations and the coordination treatment of electrodeposition process parameters in electrolytic equipment in 7 stages. The concave-convex of the surface of the copper foil is controlled to the limit, the micro coarsening particles are controlled to be between 100 and 800nm, and the particles are uniformly distributed.

The invention realizes low rough surface roughness, improves the microstructure uniformity of the copper foil, realizes non-toxic and environment-friendly production, and after the roughening treatment, the rough surface roughness Rz of the 12-micron electrolytic copper foil is less than or equal to 2 mu m, the anti-stripping strength is more than or equal to 1.3kgf/cm, and the copper foil has no oxidation phenomenon under the conditions of high temperature of 250 ℃ and 30 min.

Drawings

FIG. 1 is a schematic view of an electrolytic cell in a roughening, curing or weakly roughening stage. Wherein 1 denotes an electrolyte, 2 denotes an anode plate, 3 denotes a copper foil matte surface, and 4 denotes a copper foil smooth surface.

FIG. 2 is a graph showing the roughness variation of the matte surface of the copper foil during the roughening, curing and weak roughening stages.

FIG. 3 is a schematic view of an electrolytic cell in an oxidation prevention stage. Wherein 1 represents an electrolyte, 3 represents a copper foil matte surface, 4 represents a copper foil smooth surface, 5 represents a zinc anode plate, and 6 represents a stainless steel anode plate.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. These examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.