Composite additive for regulating and controlling grain size of electrolytic copper foil and use method of composite additive

Abstract

The invention relates to a composite additive for regulating and controlling the grain size of an electrolytic copper foil and a use method of the composite additive, the composite additive is composed of 3-cyanoacrolein and thioacetic acid, and regulation and control of the grain size of the copper foil are achieved by adjusting the proportion of all the components in the composite additive. By adopting the composite additive disclosed by the invention, the average grain size of the electrolytic copper foil can be regulated and controlled to be 0.5-10 microns, the grains of the copper foil are fine, the etching performance is excellent, and the composite additive is suitable for the field of fine lines; the copper foil is large in grain, small in signal transmission loss and suitable for the high-frequency and high-speed field.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic copper foil, and particularly relates to a composite additive for regulating the grain size of electrolytic copper foil and a use method thereof. Background Art

[0002] Traditional additives used in electrolytic copper foil mainly include collagen, gelatin, cellulose, etc. These additives mainly play the role of leveling the rough surface of the electrolytic copper foil. The grain morphology of the copper foil is mainly a coarse columnar crystal structure perpendicular to the titanium roller surface. This coarse columnar crystal has poor stability. During the high-temperature pressing process of the downstream copper clad laminate, the grain structure is unstable, and some columnar crystals will be transformed into block crystals, forming a mixed structure of columnar crystals and block crystals. During the crystal transformation process, the dimensional stability of the copper foil will be poor. Due to the poor uniformity of the grain size, the loss of the copper foil during signal transmission becomes larger, which is not suitable for high-end fine lines and high-frequency and high-speed lines. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a composite additive for regulating the grain size of electrolytic copper foil and a method for using the composite additive, wherein the composite additive enables the crystal structure and grain size of the electrolytic copper foil to be adjustable.

[0004] The invention provides a composite additive for regulating the grain size of electrolytic copper foil, characterized in that the composite additive consists of 3-cyanoacrolein and thioacetic acid.

[0005] Preferably, the concentration of 3-cyanoacrolein is 2-10 g / L, and the concentration of thioacetic acid is 5-20 g / L.

[0006] The present invention also provides a method for using a composite additive for regulating the grain size of electrolytic copper foil, comprising the following steps:

[0007] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve into a copper sulfate electrolyte, and then preheating after multi-stage filtration and purification;

[0008] (2) introducing the composite additive and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0009] (3) The above-mentioned green foil electrolyte is continuously electroplated on the cathode roller through a green foil machine to produce electrolytic copper foil.

[0010] Preferably, the purity of the copper element in step (1) is greater than 99.5%.

[0011] Preferably, the copper ion concentration in the copper sulfate electrolyte in step (1) is 75-95 g / L, and the acid content is 100-140 g / L.

[0012] Preferably, the chloride ion concentration in the raw foil electrolyte in step (2) is 5 - 20 mg / L.

[0013] Preferably, the electrolytic cathode of the raw foil machine in step (3) is a seamless drum - type titanium roll, and the electrolytic anode is a DSA - coated titanium anode plate.

[0014] Preferably, the electroplating process parameters in step (3) are: the temperature of the raw foil electrolyte is 50 - 60 °C, and the current density is 60 - 110 A / dm 2 .

[0015] Preferably, the average grain size of the electrolytic copper foil obtained in step (3) is regulated within the range of 0.5 - 10 μm.

[0016] Preferably, the average grain size of the electrolytic copper foil obtained in step (3) is less than 1.0 μm, which is applicable to the field of fine circuits; the average grain size is greater than 5.0 μm, which is applicable to the field of high - frequency and high - speed.

[0017] In the present invention, by introducing a composite additive to replace the traditional additive in the electrolytic raw foil process, the crystal structure and grain size of the electrolytic copper foil are regulated. This composite additive can, on the one hand, accelerate the formation of nucleation cores, and on the other hand, inhibit the growth of columnar crystals, achieving a uniform equiaxed crystal structure and regulating the grain size. The equiaxed crystals have high stability. During the downstream lamination process of the copper foil, the crystal structure will not change due to high temperature, and the copper foil has high dimensional stability. The electrolytic copper foil with a fine equiaxed crystal structure has good etching performance and is applicable to the field of fine circuits; while the electrolytic copper foil with a larger equiaxed crystal structure has low signal transmission loss and is applicable to the field of high - frequency and high - speed.

[0018] Beneficial effects

[0019] In the composite additive formula of the present invention, 3 - cyanoacrolein mainly plays a role in leveling the surface of the copper foil. Under the synergistic effect of thioacetic acid, it can enhance the cathodic polarization in the copper electrodeposition process and play a certain inhibitory role in the electrodeposition of copper atoms. By only adjusting the concentration ratio of 3 - cyanoacrolein and thioacetic acid in the composite additive formula, the crystal structure and grain size of the copper foil can be regulated. The average grain size of the electrolytic copper foil can be regulated to be 0.5 - 10 μm. The copper foil has fine grains and excellent etching performance, which is suitable for the field of fine circuits; the copper foil has large grains and low signal transmission loss, which is applicable to the field of high - frequency and high - speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 EBSD of the cross - section of the 12 - μm copper foil in Comparative Example 1;

[0021] Figure 2This is the EBSD of the cross section of the 12 μm copper foil in Example 1;

[0022] Figure 3 This is the EBSD of the cross section of the 12 μm copper foil in Example 2;

[0023] Figure 4 This is the EBSD of the cross section of the 12μm copper foil in Example 3. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0025] Comparative Example 1

[0026] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0027] (2) introducing the traditional additive collagen and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0028] (3) The above-mentioned green foil electrolyte is continuously electroplated on a cathode roller through a green foil machine to produce copper foil. The green foil machine electrolysis cathode is a seamless drum-type titanium roller, and the electrolysis anode is a DSA-coated titanium anode plate.

[0029] In the raw foil electrolyte, the copper ion concentration is 90g / L, the acid content is 120g / L, the chloride ion concentration is 20mg / L, and the collagen concentration is 3g / L. The temperature of the raw foil electrolyte is 55℃, and the current density is 100A / dm 2 .

[0030] Under the above process conditions, the cross-section EBSD of the prepared 12μm electrolytic copper foil is as follows: Figure 1 As shown, its crystal structure is a coarse columnar crystal structure in the electrodeposition direction. This columnar crystal structure is unstable. During the downstream high-temperature pressing process of the copper foil and the resin, part of the columnar crystal structure will be transformed into coarse block crystals, resulting in reduced dimensional stability of the copper foil and poor etching performance.

[0031] Comparative Example 2

[0032] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0033] (2) introducing additives 3-cyanoacrolein and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0034] (3) The above-mentioned raw foil electrolyte is continuously electroplated on a cathode roller through a raw foil machine to produce raw foil. The electrolytic cathode of the raw foil machine is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

[0035] In the raw foil electrolyte, the copper ion concentration is 90g / L, the acid content is 120g / L, the chloride ion concentration is 20mg / L, and the 3-cyanoacrolein concentration is 5g / L. The temperature of the raw foil electrolyte is 55°C and the current density is 100A / dm 2 .

[0036] Under the above process conditions, the crystal structure of the cross section of the prepared 12 μm electrolytic copper foil is the same as that of Comparative Example 1, which is a coarse columnar crystal structure in the electrodeposition direction.

[0037] Comparative Example 3

[0038] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0039] (2) introducing additives of thioacetic acid and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0040] (3) The above-mentioned raw foil electrolyte is continuously electroplated on a cathode roller through a raw foil machine to produce raw foil. The electrolytic cathode of the raw foil machine is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

[0041] In the raw foil electrolyte, the copper ion concentration is 90g / L, the acid content is 120g / L, the chloride ion concentration is 20mg / L, and the thioacetic acid concentration is 10g / L. The temperature of the raw foil electrolyte is 55℃, and the current density is 100A / dm 2 .

[0042] Under the above process conditions, the crystal structure of the cross section of the prepared 12 μm electrolytic copper foil is the same as that of Comparative Example 1, which is a coarse columnar crystal structure in the electrodeposition direction.

[0043] Example 1

[0044] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0045] (2) introducing a composite additive (3-cyanoacrolein and thioacetic acid) and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0046] (3) The above-mentioned raw foil electrolyte is continuously electroplated on a cathode roller through a raw foil machine to produce raw foil. The electrolytic cathode of the raw foil machine is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

[0047] In the raw foil electrolyte, the copper ion concentration is 90g / L, the acid content is 120g / L, the chloride ion concentration is 20mg / L, the 3-cyanoacrolein concentration is 10g / L, and the thioacetic acid concentration is 5g / L. The temperature of the raw foil electrolyte is 55℃, and the current density is 100A / dm 2 .

[0048] Under the above process conditions, the cross-section EBSD of the prepared 12μm electrolytic copper foil is as follows: Figure 2 As shown, its crystal structure is a coarse equiaxed crystal structure with an average grain size of 10μm, few grain boundaries, and low electrical signal transmission loss, making it suitable for high-frequency and high-speed lines.

[0049] Example 2

[0050] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0051] (2) introducing a composite additive (3-cyanoacrolein and thioacetic acid) and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0052] (3) The above-mentioned raw foil electrolyte is continuously electroplated on a cathode roller through a raw foil machine to produce raw foil. The electrolytic cathode of the raw foil machine is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

[0053] In the raw foil electrolyte, the copper ion concentration is 90g / L, the acid content is 120g / L, the chloride ion concentration is 20mg / L, the concentration of 3-cyanoacrolein is 5g / L, and the concentration of thioacetic acid is 10g / L. The temperature of the raw foil electrolyte is 55℃, and the current density is 100A / dm 2 .

[0054] Under the above process conditions, the cross-section EBSD of the prepared 12μm electrolytic copper foil is as follows: Figure 3 As shown, its crystal structure is an equiaxed crystal structure with an average grain size of 3 μm, taking into account both the signal transmission performance and etching performance of the copper foil.

[0055] Example 3

[0056] (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve the copper into a copper sulfate electrolyte; the electrolyte is purified by multi-stage filtration and then preheated;

[0057] (2) introducing a composite additive (3-cyanoacrolein and thioacetic acid) and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte;

[0058] (3) Continuously electroplate the above-mentioned raw foil electrolyte on the cathode roller through a raw foil machine. The electrolytic cathode of the raw foil machine is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

[0059] In the raw foil electrolyte, the copper ion concentration is 90 g / L, the acid content is 120 g / L, the chloride ion concentration is 20 mg / L, the concentration of 3-cyanoacrolein is 2 g / L, and the concentration of thioacetic acid is 20 g / L. The temperature of the raw foil electrolyte is 55 °C, and the current density is 100 A / dm 2 .

[0060] Under the above process conditions, the cross-sectional EBSD of the prepared 12-μm electrolytic copper foil is as Figure 4 shown. Its crystal structure is a fine equiaxed crystal structure, and the average grain size is 0.5 μm. This fine equiaxed crystal structure is very stable and will not undergo obvious grain growth during the downstream high-temperature pressing process. The copper foil has high dimensional stability, and due to more grain boundaries, the downstream circuit etching speed is fast, and the copper foil etching performance is excellent, which is suitable for the field of fine circuits.

[0061] It can be seen from the examples and comparative examples that compared with traditional additives, the composite additive in this invention can achieve the transformation of the crystal structure of electrolytic copper foil from a coarse columnar crystal structure to an equiaxed crystal structure, and can adjust its grain size within a large range to meet the requirements of different customer application fields for the signal transmission and etching performance of copper foil.

[0062] Finally, it should be emphasized that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A composite additive for regulating the grain size of electrolytic copper foil, characterized in that: The composite additive consists of 3-cyanoacrolein and thioacetic acid.

2. The composite additive according to claim 1, wherein: The concentration of the 3-cyanoacrolein is 2-10 g / L, and the concentration of the thioacetic acid is 5-20 g / L.

3. A method for using the composite additive for regulating the grain size of electrolytic copper foil as claimed in any one of claims 1 to 2, comprising the following steps: (1) adding copper to a copper dissolving tank containing sulfuric acid to dissolve into a copper sulfate electrolyte, and then preheating after multi-stage filtration and purification; (2) introducing the composite additive and hydrochloric acid into the copper sulfate electrolyte to obtain a raw foil electrolyte; (3) The above-mentioned green foil electrolyte is continuously electroplated on the cathode roller through a green foil machine to produce electrolytic copper foil.

4. The usage method according to claim 3, characterized in that: The purity of the copper element in step (1) is greater than 99.5%.

5. The usage method according to claim 3, characterized in that: The copper ion concentration in the copper sulfate electrolyte in the step (1) is 75-95 g / L, and the acid content is 100-140 g / L.

6. The usage method according to claim 3, wherein: The chloride ion concentration in the raw foil electrolyte in step (2) is 5 to 20 mg / L.

7. The method of use according to claim 3, characterized in that: The electrolytic cathode of the foil machine in step (3) is a seamless drum-type titanium roller, and the electrolytic anode is a DSA-coated titanium anode plate.

8. The usage method according to claim 3, characterized in that: The electroplating process parameters in step (3) are as follows: the temperature of the raw foil electrolyte is 50 - 60 °C, and the current density is 60 - 110 A / dm 2 .

9. The usage method according to claim 3, characterized in that: The average grain size of the electrolytic copper foil obtained in step (3) is regulated within the range of 0.5 to 10 μm.

10. The usage method according to claim 3, characterized in that: The electrolytic copper foil obtained in step (3) has an average grain size of less than 1.0 μm, which is suitable for the field of fine circuits; and has an average grain size of greater than 5.0 μm, which is suitable for the field of high frequency and high speed.

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