Preparation method of copper foil with carrier

Abstract

The invention provides a preparation method of copper foil with a carrier. The preparation method comprises the step of generating an oxidation film layer on the surface of a carrier copper layer through oxidation. According to the method, a compact oxidation film layer is generated on the surface of a carrier copper layer through an oxidation method, the compact oxidation film layer serves as a separation interface of an ultrathin copper layer and the carrier copper layer, introduction of other impurity metal or organic matter is avoided, and the problem that the performance of the copper foil is reduced due to the fact that the impurity metal or organic matter migrates to the copper foil in the follow-up machining process is solved; according to the method, the production process and control are simplified, and the method is simple; the prepared copper foil with the carrier has excellent separating force stability. Experimental results show that after the copper foil with the carrier is pressed with a prepreg at the temperature of less than or equal to 250 DEG C, the high-temperature and normal-temperature copper foil interlayer separating force range is less than or equal to 30 gf / cm.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electroplating and the technical field of copper foil manufacturing, and particularly relates to a preparation method of carrier copper foil. BACKGROUND

[0002] In the field of modern electronic technology, copper foil is an important material, mainly used for making printed circuit boards (PCB) and other electronic components. With the continuous iteration and upgrading of the fineness of terminal devices, copper foil has also begun to derive special copper foil with various characteristics. Among them, the carrier copper foil is mainly composed of two copper layers and a barrier layer in between, in which the ultra-thin copper layer provides good electrical conductivity and fine line processing capability, and the barrier layer serves to isolate the two copper layers. Since one of the copper layers in the carrier copper foil is usually ≤3 μm thick, it cannot be directly passed through the roller system of the copper foil production machine, so it is produced in conjunction with the other copper foil which is usually 18 μm thick. In use, it will be peeled off at the downstream section of the copper foil processing (usually after hot pressing with a prepreg), at which time the barrier layer set between the two copper foils plays the role of separating the two copper foils.

[0003] The core of the manufacturing technology of carrier copper foil lies in the material selection and attachment process of the barrier layer. The existing technology often uses non-copper metals or high-temperature resistant organic materials as the material of the barrier layer, and creates a separable interface by the lattice difference between different metals or by directly incorporating an organic film, achieving the effect of high-temperature separability. In addition, there are electroplating process, coating process and magnetron sputtering process in the attachment of the barrier layer material. Due to different attachment processes, the density or uniformity of the material is different, affecting the peeling performance of the barrier layer, so the selection of the attachment process also significantly affects the separable characteristics.

[0004] No matter what attachment process and material the barrier layer of the carrier copper foil uses, it is inevitable to introduce non-copper metal elements, which not only increases the complexity of the preparation process, but also has the risk of bringing these elements into other plating solutions, thereby polluting other plating solutions after the barrier layer. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a preparation method of carrier copper foil, which is simple and avoids the introduction of other impurity metals or organic materials; the carrier copper foil has excellent separation force stability.

[0006] The present application provides a preparation method of carrier copper foil, which comprises generating an oxide film layer on the surface of the carrier copper layer.

[0007] Preferably, the oxide film layer is generated by high-temperature oxidation;

[0008] The high-temperature oxidation temperature is greater than or equal to 130 DEG C, and the high-temperature oxidation time is greater than or equal to 0.5 h.

[0009] Preferably, it further comprises:

[0010] Then, an ultra-thin copper layer is deposited on the surface of the oxidation film, and then the surface is roughened and subjected to an oxidation-preventing treatment.

[0011] Preferably, the electrolyte used for depositing the ultra-thin copper layer comprises Cu 2+ 95-100 g / L and sulfuric acid 105-115 g / L;

[0012] The temperature for depositing the ultra-thin copper layer is 38-42 DEG C, and the current density is 2.8-3.2 A / dm 2 .

[0013] Preferably, an alkaline copper plating layer is deposited on the surface of the oxidation film before depositing the ultra-thin copper layer;

[0014] The electrolyte used for depositing the alkaline copper plating layer comprises copper pyrophosphate 78-83 g / L and potassium pyrophosphate 310-320 g / L and potassium citrate 18-23 g / L;

[0015] The temperature for depositing the alkaline copper plating layer is 50-55 DEG C, and the current density is 18-22 A / dm 2 .

[0016] Preferably, the thickness of the oxidation film layer is 0.1-500 nm;

[0017] The thickness of the carrier copper layer is 9-20 μm.

[0018] Preferably, the carrier copper layer is immersed in sulfuric acid with a concentration of 80-90 g / L before the oxidation film layer is formed;

[0019] The temperature for the immersion is 38-42 DEG C, and the time is 18-23 s.

[0020] Preferably, the electrolyte used for the roughening comprises a roughening electrolyte and a solidification electrolyte;

[0021] The roughening electrolyte comprises sulfuric acid 88-92 g / L and Cu 2+ with a concentration of 23-28 g / L, and the electroplating current density is 12-15 A / dm 2 .

[0022] The solidification electrolyte comprises sulfuric acid 93-97 g / L and Cu 2+ with a concentration of 53-58 g / L, and the electroplating current density is 14-16 A / dm 2 .

[0023] Preferably, the carrier copper layer is prepared by electrolysis of an electrolyte;

[0024] Electrolyte includes 110-115 g / L sulfuric acid and Cu 2+ Concentration 95-100 g / L

[0025] Temperature of electrolysis is 50-55℃.

[0026] Preferably, the carrier copper foil is pressed with the prepreg at ≤250℃, and the separation force of the copper-clad plate is 5-50 gf / cm.

[0027] The application provides a preparation method of a carrier copper foil, which comprises generating an oxide film layer on the surface of a carrier copper layer by oxidation. The method generates a dense oxide film layer on the surface of the carrier copper layer by oxidation, so as to serve as a separation interface between the ultra-thin copper layer and the carrier copper layer, avoids the introduction of other impurity metals or organic matters, and further avoids the performance decline of the copper foil caused by the migration of the impurity metals or organic matters to the copper foil itself in the subsequent processing process. The method simplifies the production process and management and control, is simple, and has excellent separation force stability. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 is a structural schematic diagram of a carrier copper foil; wherein (1) is a carrier copper layer, (2) is a barrier layer, and (3) is an ultra-thin copper layer.

[0029] Figure 2 Fig. 2 is a high-temperature test separation force result diagram of Example 1. DETAILED DESCRIPTION

[0030] The application provides a preparation method of a carrier copper foil, which comprises generating an oxide film layer on the surface of a carrier copper layer by oxidation.

[0031] The application generates a dense oxide film layer on the surface of the carrier copper layer by oxidation, so as to serve as a barrier layer of the carrier copper foil, without the need for magnetron sputtering or electroplating deposition, and the preparation steps are simple.

[0032] The application preferably generates the oxide film layer in a high-temperature oxidation manner; the application preferably bakes in an oven to generate the oxide film layer; the high-temperature oxidation temperature is greater than or equal to 130 DEG C, preferably 130 DEG C to 180 DEG C; specifically, 130 DEG C, 135 DEG C, 140 DEG C, 145 DEG C, 150 DEG C, 155 DEG C, 160 DEG C, 165 DEG C, 170 DEG C, 175 DEG C or 180 DEG C; the high-temperature oxidation time is greater than or equal to 0.5 h, preferably 0.5 h to 14 h; specifically, 0.5 h, 1 h, 1.5 h, 2.0 h, 2.5 h, 3.0 h, 3.5 h, 4.0 h, 4.5 h, 5.0 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h, 12 h, 12.5 h, 13 h, 13.5 h or 14 h.

[0033] The carrier copper layer in the application is prepared by electrolysis of electrolyte; the electrolyte comprises 110-115 g / L of sulfuric acid and Cu 2+ a concentration of 95-100 g / L; specifically, the sulfuric acid content is 110 g / L, 111 g / L, 112 g / L, 113 g / L, 114 g / L or 115 g / L, and the Cu 2+ a concentration of 95 g / L, 96 g / L, 97 g / L, 98 g / L, 99 g / L or 100 g / L; the electrolysis temperature is 50-55 DEG C, and specifically, 50 DEG C, 51 DEG C, 52 DEG C, 53 DEG C, 54 DEG C or 55 DEG C.

[0034] The application soaks the carrier copper layer with sulfuric acid with a concentration of 80-90 g / L before forming the oxide film layer, which can remove foreign matter or impurities on the surface and facilitate the formation of a uniform oxide film layer; the sulfuric acid concentration is specifically 80 g / L, 81 g / L, 82 g / L, 83 g / L, 84 g / L, 85 g / L, 86 g / L, 87 g / L, 88 g / L, 89 g / L or 90 g / L; the soaking temperature is 38-42 DEG C, and specifically, 38 DEG C, 39 DEG C, 40 DEG C, 41 DEG C or 42 DEG C; the time is 18-23 s, and specifically, 18 s, 19 s, 20 s, 21 s, 22 s or 23 s.

[0035] After forming the oxide film layer, the application preferably deposits an ultrathin copper layer on the surface of the oxide film; then, the surface is roughened and subjected to oxidation prevention treatment.

[0036] The application preferably deposits an alkaline copper plating layer on the surface of the oxide film in forming the ultrathin copper layer; the application deposits an alkaline copper plating layer to protect the oxide film layer barrier layer. The electrolyte used for depositing the alkaline copper plating layer comprises 78-83 g / L of copper pyrophosphate, 310-320 g / L of potassium pyrophosphate and 18-23 g / L of potassium citrate; the temperature for depositing the alkaline copper plating layer is 50-55 DEG C, and the current density is 18-22 A / dm2 Specifically, the content of copper pyrophosphate is 78 g / L, 79 g / L, 80 g / L, 81 g / L, 82 g / L or 83 g / L; the content of potassium pyrophosphate is 310 g / L, 311 g / L, 312 g / L, 313 g / L, 314 g / L, 315 g / L, 316 g / L, 317 g / L, 318 g / L, 319 g / L or 320 g / L; the content of potassium citrate is 18 g / L, 19 g / L, 20 g / L, 21 g / L, 22 g / L or 23 g / L; the temperature for depositing the alkaline copper plating layer is specifically 50℃, 51℃, 52℃, 53℃, 54℃ or 55℃, and the current density is specifically 18A / dm 2 , 19A / dm 2 , 20A / dm 2 , 21A / dm 2 or 22A / dm 2 .

[0037] After the alkaline copper plating layer is deposited, the alkaline plating or acid plating deposition is continued to form an ultra-thin copper layer in the present application; the electrolyte for acid plating includes Cu 2+ 95-100 g / L and sulfuric acid 105-115 g / L; specifically, the content of Cu 2+ is 95 g / L, 96 g / L, 97 g / L, 98 g / L, 99 g / L or 100 g / L; and the content of sulfuric acid is 105 g / L, 106 g / L, 107 g / L, 108 g / L, 109 g / L, 110 g / L, 111 g / L, 112 g / L, 113 g / L, 114 g / L or 115 g / L.

[0038] The temperature for depositing the ultra-thin copper layer is 38-42℃, specifically 38℃, 39℃, 40℃, 41℃ or 42℃; and the current density is 2.8-3.2A / dm 2 ; specifically, it can be 2.8A / dm 2 , 2.9A / dm 2 , 3.0A / dm 2 , 3.1A / dm 2 or 3.2A / dm 2 .

[0039] The electrolyte for roughening in the present application includes a rough layer plating electrolyte and a solidification electrolyte; the surface rough layer is first plated on the surface of the ultra-thin copper layer by using the rough layer plating electrolyte, and then the solidification electrolyte is used for solidification plating to complete the surface roughening treatment of the ultra-thin copper layer.

[0040] In the present application, the rough layer plating electrolyte includes sulfuric acid 88-92 g / L and Cu 2+ concentration 23-28 g / L, and the plating current density is 12-15A / dm 2Specifically, the roughening plating electrolyte comprises 88 g / L, 89 g / L, 90 g / L, 91 g / L or 92 g / L of sulfuric acid; and Cu 2+ The concentration of the sulfuric acid is 23 g / L, 24 g / L, 25 g / L, 26 g / L, 27 g / L or 28 g / L.

[0041] The solidification electrolyte comprises 93-97 g / L of sulfuric acid and Cu 2+ The concentration of the sulfuric acid is 53-58 g / L, and the plating current density is 14-16 A / dm 2 Specifically, the content of the sulfuric acid is 93 g / L, 94 g / L, 95 g / L, 96 g / L or 97 g / L, and the concentration of Cu 2+ The concentration of the sulfuric acid is 53 g / L, 54 g / L, 55 g / L, 56 g / L, 57 g / L or 58 g / L.

[0042] The present application performs the anti-oxidation treatment on the roughened copper foil surface; the copper foil is sequentially put into the electrolyte with the concentration of sulfuric acid of 73-77 g / L and the concentration of cobalt ions of 4.5-5.5 g / L, and the electrolysis temperature is 40℃; and the surface anti-oxidation treatment is performed in the anti-oxidation electrolyte with the concentration of sulfuric acid of 85 g / L and the concentration of zinc of 7 g / L, and the electrolysis temperature is 45℃.

[0043] After the anti-oxidation treatment, the present application removes the surface electrolyte or water stain through water washing and oven drying, and obtains the carrier copper foil.

[0044] In the present application, the thickness of the oxidation film layer in the carrier copper foil is 0.1-500 nm; the thickness of the carrier copper layer is 15-20 μm, and specifically can be 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm. The thickness of the ultra-thin copper layer is 2.5-3.5 μm, and specifically can be 2.5 μm, 2.6 μm, 2.7 μm, 2.8 μm, 2.9 μm, 3.0 μm, 3.1 μm, 3.2 μm, 3.3 μm, 3.4 μm or 3.5 μm.

[0045] In the present application, the carrier copper foil is cut into a 100*15 mm test sample at normal temperature, and directly tested on a precision copper foil electronic stripping machine, i.e. without pressing and directly testing. The average separation force between the two layers of the carrier copper foil is measured at a vertical tensile angle of 90°. The normal temperature separation force of the carrier copper foil is 5-20 gf / cm, and specifically can be 5 gf / cm, 6 gf / cm, 7 gf / cm, 8 gf / cm, 9 gf / cm, 10 gf / cm, 11 gf / cm, 12 gf / cm, 13 gf / cm, 14 gf / cm, 15 gf / cm, 16 gf / cm, 17 gf / cm, 18 gf / cm, 19 gf / cm or 20 gf / cm.

[0046] The copper foil with carrier and the prepreg are pressed at ≤250 DEG C to obtain a copper-clad plate; preferably, the pressing is carried out at ≥150 DEG C and ≤250 DEG C. The copper-clad plate is cut into a 100*15mm test sample, and tested on a precision copper foil electronic stripping machine. The separation force between the two layers of the copper foil is measured at a vertical stretching angle of 90 DEG.

[0047] In the present application, the high-temperature separation force of the copper-clad plate is 5-50 gf / cm, and can be 5 gf / cm, 6 gf / cm, 7 gf / cm, 8 gf / cm, 9 gf / cm, 10 gf / cm, 11 gf / cm, 12 gf / cm, 13 gf / cm, 14 gf / cm, 15 gf / cm, 16 gf / cm, 17 gf / cm, 18 gf / cm, 19 gf / cm, 20 gf / cm, 21 gf / cm, 22 gf / cm, 23 gf / cm, 24 gf / cm, 25 gf / cm, 26 gf / cm, 27 gf / cm, 28 gf / cm, 29 gf / cm, 30 gf / cm, 31 gf / cm, 32 gf / cm, 33 gf / cm, 34 gf / cm, 35 gf / cm, 36 gf / cm, 37 gf / cm, 38 gf / cm, 39 gf / cm, 40 gf / cm, 41 gf / cm, 42 gf / cm, 43 gf / cm, 44 gf / cm, 45 gf / cm, 46 gf / cm, 47 gf / cm, 48 gf / cm, 49 gf / cm or 50 gf / cm.

[0048] The copper foil with carrier prepared by the preparation method provided in the present application comprises an ultrathin copper layer and a carrier copper layer; and an oxide film layer is generated on the surface of the carrier copper layer in contact with the ultrathin copper layer. The ultrathin copper layer is relatively thin in thickness; the carrier copper layer serves as a supporting carrier; and the barrier layer, i.e., the oxide film layer, provides the performance of separating the two copper foil layers, is formed by direct oxidation, is simple in method, and is realized by temperature and time, and is relatively easy to control.

[0049] Compared with the prior art, the present application has the following beneficial effects:

[0050] 1. Simplification of preparation steps: the present application uses high-temperature oxidation, and only uses the easy-oxidation property of the copper foil itself to generate an oxide film layer as the separation interface between the two copper layers, without the need for magnetron sputtering or electroplating deposition of a barrier layer, so that the preparation steps are simple.

[0051] 2. The carrier copper foil preparation technology of the present application generates a dense oxide film layer on the surface of the carrier copper layer, then deposits an ultrathin copper layer on the surface of the oxide film, and performs surface roughening and anti-oxidation treatment, without the need for introducing other impurity metals or organic matter. This avoids the problem of performance degradation that may be caused by the introduction of impurity metals or organic matter, and is conducive to the stability control in the product manufacturing process.

[0052] 3. Separation stability: Since the barrier layer of the carrier copper foil of the present application uses copper oxide with high temperature resistance, the copper oxide generally forms a dense surface layer structure, which can effectively block the migration path of atoms or ions. The oxide layer formed on the copper surface at high temperature can inhibit the further oxidation of the copper matrix, hinder the inward diffusion of oxygen or the outward diffusion of metal ions. At the same time, the ion diffusion in the oxide lattice requires higher activation energy, thereby slowing down the diffusion rate, and the mismatch between the oxide lattice and the copper lattice can lead to a reduction in defects at the interface, inhibiting the formation of diffusion channels. This makes the carrier copper foil after being pressed with a prepreg at a temperature of ≤250℃ have an interlayer separation force of the copper foil layer at high temperature and room temperature ≤30 gf / cm.

[0053] In order to further illustrate the present application, a preparation method of a carrier copper foil provided by the present application is described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0054] Example 1

[0055] The present example provides a high-temperature stable carrier copper foil, which comprises a carrier copper layer with a thickness of 18 μm, a barrier layer, and an ultrathin copper layer with a thickness of 3 μm. The specific preparation method is as follows:

[0056] (1) Preparation of carrier copper layer:

[0057] Use a CuSO4·5H2O electrolyte containing 110 g / L of sulfuric acid and Cu2+ ion concentration of 97 g / L, and electrolyze in an electrolyte at a temperature of 54℃ to obtain a carrier copper layer with a thickness of 18 μm; 2+

[0058] (2) Pretreatment of carrier copper layer:

[0059] Use sulfuric acid with a concentration of 85 g / L to soak both sides of the carrier copper layer for 20 s at a treatment liquid temperature of 40℃, and wait for use;

[0060] (3) Preparation of barrier layer:

[0061] Put the carrier copper layer pretreated in step (2) into an oven at a temperature of 180℃ for 4 h, and take it out after forming a dense oxide barrier layer on the surface of the copper foil.

[0062] (4) Preparation of ultrathin copper layer

[0063] Put the carrier copper layer + barrier layer structure obtained in step (3) into a solution containing copper pyrophosphate with a concentration of 80 g / L, potassium pyrophosphate with a concentration of 320 g / L, and potassium citrate with a concentration of 20 g / L, and immerse it in the solution at a temperature of 40℃ at a current density of 3 A / dm2 for 20 min to obtain an ultrathin copper layer with a thickness of 3 μm. 2 ​A layer of alkaline copper is plated at a current density to protect the oxide barrier layer.

[0064] The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer. 2+ The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer. 2 The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer.

[0065] (5) Copper layer roughening and oxidation prevention treatment

[0066] The structure obtained in step (4) is introduced into a CuSO4 electrolyte with a concentration of 90 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L, with the ultra-thin copper layer facing the anode plate and the carrier copper layer facing away from the anode plate, to form a surface roughening layer at an average current density of 14 A / dm2. 2+ The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer. 2 The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer. 2+ The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer. 2 The resulting carrier copper layer + barrier layer + alkaline copper layer structure is then introduced into a CuSO4 electrolyte with a concentration of 110 g / L H2SO4 and a Cu2+ ion concentration of 25 g / L at a temperature of 40°C and a current density of 20 A / dm2 to form a surface roughening layer.

[0067] The roughened copper foil is then subjected to oxidation prevention treatment by being sequentially introduced into oxidation prevention electrolytes with a concentration of 75 g / L H2SO4 and 5 g / L Co at a temperature of 40°C and a concentration of 85 g / L H2SO4 and 7 g / L Zn at a temperature of 45°C, and then washed with water and dried in an oven to remove the electrolyte or water stains on the surface, thereby obtaining the carrier copper foil.

[0068] The copper foil is cut into a 100*15 mm test strip at room temperature and tested on a precision copper foil electronic stripping machine. The average separation force between the two layers of the copper foil is 7.7 gf / cm at a 90° vertical tensile angle.

[0069] The copper foil is pressed with a prepreg at a temperature of 250°C to form a copper-clad plate, and the copper-clad plate is cut into a 100*15 mm test strip and tested on a precision copper foil electronic stripping machine. The results are shown in Table 2. Figure 2 where Plot1 and Plot2 are test data from two tests, each divided by 1.5 cm, and the average value is calculated, i.e. the average separation force between the two layers of the copper foil is 15.1 gf / cm at a 90° vertical tensile angle.

[0070] Example 2

[0071] The difference between Example 1 and Example 2 is that the barrier layer baking time in the third step is adjusted to 12 h.

[0072] Example 3

[0073] The difference from Example 1 is that the barrier layer baking time in the third step is adjusted to 10 h, and the baking temperature is adjusted to 130℃.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the barrier layer is not baked in the third step.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that the barrier layer baking temperature in the third step is adjusted to 50℃, and the baking time is 1 h.

[0078] Comparative Example 3

[0079] The difference from Example 1 is that the barrier layer baking temperature in the third step is adjusted to 100℃, and the baking time is 12 h.

[0080] The copper foils prepared in the examples and comparative examples are subjected to separation force test, and the results are shown in Table 1:

[0081] Table 1

[0082]

[0083] As can be seen from Table 1, when the barrier layer is prepared at less than 130℃, it cannot be separated after being pressed with a prepreg at high temperature.

[0084] As can be seen from the above examples, the present application provides a preparation method of a carrier copper foil, which comprises generating an oxide film layer on the surface of a carrier copper layer by oxidation. The method generates a dense oxide film layer on the surface of the carrier copper layer by oxidation, which serves as the separation interface between the ultra-thin copper layer and the carrier copper layer, avoids the introduction of other impurity metals or organic matter, and thus avoids the problem of performance degradation of the copper foil caused by the migration of impurity metals or organic matter to the copper foil itself in the subsequent processing process. The method simplifies the production process and control, and is simple. The carrier copper foil prepared has excellent separation force stability. Experimental results show that the carrier copper foil has a copper foil interlayer separation force of ≤30 gf / cm at high temperature and room temperature after being pressed with a prepreg at a temperature of ≤250℃.

[0085] The above description is only preferred embodiments of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, which should be considered as the protection scope of the present application.

Claims

1. A method for preparing a copper foil with a carrier, comprising oxidizing the surface of a copper carrier layer to form an oxide film.

2. The preparation method according to claim 1, characterized in that, An oxide film is generated by high-temperature oxidation. The high-temperature oxidation temperature is greater than or equal to 130℃, and the high-temperature oxidation time is greater than or equal to 0.5h.

3. The preparation method according to claim 1, characterized in that, Also includes: Then, an ultrathin copper layer is deposited on the oxide film surface; followed by surface roughening and anti-oxidation treatment.

4. The preparation method according to claim 1, characterized in that, The electrolyte used for depositing ultrathin copper layers includes Cu. 2+ 95–100 g / L and sulfuric acid 105–115 g / L; The deposition temperature for ultrathin copper layers is 38–42 °C, and the current density is 2.8–3.2 A / dm³. 2 .

5. The preparation method according to claim 1, characterized in that, An alkaline copper plating layer is deposited on the oxide film surface before the deposition of an ultrathin copper layer; The electrolyte used for depositing alkaline copper plating includes 78-83 g / L copper pyrophosphate, 310-320 g / L potassium pyrophosphate, and 18-23 g / L potassium citrate. The deposition temperature for alkaline copper plating is 50–55℃, and the current density is 18–22 A / dm³. 2 .

6. The preparation method according to claim 1, characterized in that, The thickness of the oxide film is 0.1–500 nm; The thickness of the carrier copper layer is 9–20 μm.

7. The preparation method according to claim 1, characterized in that, Before forming the oxide film, the copper substrate was soaked in sulfuric acid with a concentration of 80-90 g / L. The soaking temperature is 38–42℃, and the soaking time is 18–23 seconds.

8. The preparation method according to claim 1, characterized in that, The electrolytes used for roughening include a roughening layer electrolyte and a curing electrolyte; The electrolyte for plating the roughening layer includes sulfuric acid at 88–92 g / L and Cu. 2+ Concentration 23–28 g / L, electroplating current density 12–15 A / dm 2 ; The curing electrolyte includes sulfuric acid (93–97 g / L) and Cu. 2+ Concentration 53–58 g / L, electroplating current density 14–16 A / dm³ 2 .

9. The preparation method according to claim 1, characterized in that, The copper carrier layer is prepared by electrolysis with an electrolyte. The electrolyte consists of 110–115 g / L sulfuric acid and Cu. 2+ Concentration 95–100 g / L; The electrolysis temperature is 50–55℃.

10. The preparation method according to claim 3, characterized in that, The carrier copper foil includes an ultrathin copper layer and a carrier copper layer; and an oxide film layer formed by oxidation on the surface of the carrier copper layer in contact with the ultrathin copper layer.

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