Test method for efficiently evaluating stability of electrolytic copper foil crystal structure

Abstract

The invention discloses a test method for efficiently evaluating the stability of an electrolytic copper foil crystal structure. A conventional detection method for the stability of an electrolytic copper foil crystal structure is usually used for evaluating by comparing the size change rates of normal-temperature and high-temperature crystals, and the whole detection process is tedious and long in period. When the crystal structure of the electrolytic copper foil is unstable, crystal grains of the electrolytic copper foil are easy to recrystallize and grow up in a high-temperature state, and the tensile strength is changed. The crystal structure stability of the electrolytic copper foil is rapidly and efficiently evaluated by testing the high-temperature tensile strength of the electrolytic copper foil and combining the normal and annealed crystal structure maps corresponding to different high-temperature tensile strength, the detection period is greatly shortened, and the method is suitable for testing the crystal structure stability of the copper foil on a large scale in the electrolytic copper foil industry.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic copper foil, and in particular to a testing method for efficiently evaluating the crystal structure stability of electrolytic copper foil. Background Art

[0002] The crystal structure stability of electrolytic copper foil is greatly affected by the additive formula and process conditions. Generally speaking, during the electrodeposition of copper atoms, the additive molecules in the electrolyte will regulate and affect the crystal morphology of copper atoms and be interspersed at the grain boundaries. Different additive processes have different effects on the stability of the crystal structure of copper foil. Copper foil exists in several different states, such as room temperature self-annealing, low temperature annealing, high temperature annealing, and high temperature non-annealing. The crystal structure stability of electrolytic copper foil is extremely important for the downstream copper clad laminate process, which will affect the machinability of downstream copper clad laminates. When the crystal structure is unstable, the crystal structure of the copper foil changes significantly during the high-temperature pressing process of the copper foil and the resin, such as: the transformation of columnar crystals to equiaxed crystals, the fusion and growth of grains, etc., resulting in problems such as warping of the board and poor dimensional stability, leading to scrapping. Therefore, for electrolytic copper foil manufacturers, how to detect and control the stability of the crystal structure of electrolytic copper foil is crucial. The crystal structure stability of electrolytic copper foil is generally judged by the change rate of grain size after annealing at room temperature and high temperature. This method requires high sample preparation because it needs to observe the crystal structure. The entire judgment cycle is long and the detection efficiency is very low.

[0003] Based on the low efficiency of the above electrolytic copper foil crystal structure stability evaluation method, the present invention develops a new and efficient method for evaluating the crystal structure stability. After high-temperature annealing, the electrolytic copper foil will grow its grains, resulting in changes in its mechanical properties, such as attenuation of tensile strength. Therefore, based on the above copper foil annealing characteristics, the high-temperature tensile strength of the copper foil can be measured to establish the relationship between the high-temperature tensile strength of the copper foil and the crystal structure stability, so as to efficiently evaluate the crystal structure stability. Compared with the original method, the detection cycle of this invention method is shortened from 4 hours to 10 minutes, and the detection efficiency is greatly improved. Summary of the invention

[0004] The object of the present invention is to provide a test method for efficiently evaluating the crystal structure stability of electrolytic copper foil, comprising the following steps:

[0005] (1) Test the high temperature tensile strength of multiple electrolytic copper foil samples. The high temperature tensile strength should have a gradient;

[0006] (2) Using EBSD to test the crystal structures of samples with different high temperature tensile strengths after annealing at room temperature and high temperature;

[0007] (3) Draw the normal and annealed crystal structure maps corresponding to different high-temperature tensile strengths, and establish the corresponding relationship between the high-temperature tensile constant and the grain size change rate;

[0008] (4) After that, the high-temperature tensile strength of the electrolytic copper foil can be directly tested to quickly determine the stability of its crystal structure.

[0009] Preferably, in the step (1), the high-temperature tensile strengths of different electrolytic copper foil samples are respectively in the range of 200 - 210 Mpa, 211 - 220 Mpa, 221 - 230 MPa, and 231 - 240 MPa.

[0010] Preferably, in the step (1), the test conditions for the high-temperature tensile strength are that the copper foil specimen strip has a width of 12.7 mm and a length of 100 mm, and the tensile strength test is carried out after maintaining the temperature at 180 °C for 5 minutes in the oven of a high-temperature universal tensile testing machine.

[0011] Preferably, the high-temperature annealing condition in the step (2) is to maintain the temperature at 180 °C for 1 h.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, the stability of the crystal structure can be evaluated only by testing the high-temperature tensile strength of the electrolytic copper foil. The detection period is shortened from 4 hours of the original method to 10 minutes, and the detection efficiency is greatly improved, which is suitable for the large-scale detection of the crystal structure stability of electrolytic copper foil by electrolytic copper foil enterprises. Description of the Drawings

[0013] Figure 1 It is the normal state and annealed state crystal structure diagrams corresponding to different high-temperature tensile strengths of the electrolytic copper foil. Detailed Embodiments

[0014] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following specific embodiments are used to further describe the present invention in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0015] Embodiment 1

[0016] (1) Place the electrolytic copper foil sample 1 on a cutting machine to cut the specimen strip, and the width of the specimen strip is 12.7 mm and the length is 100 mm;

[0017] (2) Turn on the high-temperature universal tensile testing machine, adjust the distance between the two fixture jaws to 50 mm, and the moving speed of the chuck is 1.27 mm / min;

[0018] (3) Preheat the oven of the high-temperature universal tensile testing machine to 180 °C. After the temperature is stable, open the oven door, vertically and centrally place the copper foil specimen strip in the upper and lower fixtures and clamp it well, then close the oven door;

[0019] (4) After the specimen strip is maintained at 180 °C in the oven for 5 min, start the high-temperature tensile strength test.

[0020] For electrolytic copper foil sample 1, the high-temperature tensile strength was measured to be 205 MPa. Comparing with Figure 1 , its grain size increased significantly after annealing, and it was determined that the crystal structure was unstable.

[0021] Example 2

[0022] (1) Place electrolytic copper foil sample 2 on a cutting machine to cut specimen strips. The width of the specimen strips is 12.7 mm and the length is 100 mm;

[0023] (2) Turn on the high-temperature universal tensile testing machine, adjust the distance between the two fixture jaws to 50 mm, and the chuck moving speed is 1.27 mm / min;

[0024] (3) Preheat the oven of the high-temperature universal tensile testing machine to 180 °C. After the temperature is stable, open the oven door, vertically and centrally place the copper foil specimen strip in the upper and lower fixtures and clamp it well, then close the oven door;

[0025] (4) After the specimen strip is kept at 180 °C in the oven for 5 minutes, start the high-temperature tensile strength test.

[0026] For electrolytic copper foil sample 2, the high-temperature tensile strength was measured to be 216 MPa. Comparing with Figure 1 , its grain size increased significantly after annealing, and it was determined that the crystal structure was unstable.

[0027] Example 3

[0028] (1) Place electrolytic copper foil sample 3 on a cutting machine to cut specimen strips. The width of the specimen strips is 12.7 mm and the length is 100 mm;

[0029] (2) Turn on the high-temperature universal tensile testing machine, adjust the distance between the two fixture jaws to 50 mm, and the chuck moving speed is 1.27 mm / min;

[0030] (3) Preheat the oven of the high-temperature universal tensile testing machine to 180 °C. After the temperature is stable, open the oven door, vertically and centrally place the copper foil specimen strip in the upper and lower fixtures and clamp it well, then close the oven door;

[0031] (4) After the specimen strip is kept at 180 °C in the oven for 5 minutes, start the high-temperature tensile strength test.

[0032] For electrolytic copper foil sample 3, the high-temperature tensile strength was measured to be 225 MPa. Comparing with Figure 1 , its grain size did not increase significantly after annealing, and it was determined that the crystal structure was stable.

[0033] Example 4

[0034] (1) Place the electrolytic copper foil sample 4 on a cutting machine to cut the test strips. The width of the test strips is 12.7 mm and the length is 100 mm.

[0035] (2) Turn on the high-temperature universal tensile testing machine, adjust the distance between the two clamp jaws to 50 mm, and the moving speed of the chuck is 1.27 mm / min.

[0036] (3) Preheat the oven of the high-temperature universal tensile testing machine to 180 °C. After the temperature is stable, open the oven door, vertically and centrally place the copper foil test strips in the upper and lower clamps, and close the oven door.

[0037] (4) After the test strips are kept at 180 °C in the oven for 5 min, start the high-temperature tensile strength test.

[0038] For the electrolytic copper foil sample 4, the measured high-temperature tensile strength is 238 MPa. Comparing Figure 1 , the grain size has not grown significantly after annealing, and it is determined that the crystal structure is stable.

[0039] It can be seen from the examples that this invention can quickly and qualitatively determine whether the crystal structure of copper foil is stable by testing the high-temperature tensile strength of electrolytic copper foil and combining with the normal and annealed crystal structure maps corresponding to the high-temperature tensile strength. Compared with the traditional method, the detection efficiency is greatly improved, and it is suitable for the determination of the crystal structure stability of a large number of copper foils in electrolytic copper foil enterprises.

[0040] The above is only the preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

Claims

1. A test method for efficiently evaluating the crystal structure stability of electrolytic copper foil, characterized in that: The steps include: (1) Test the high temperature tensile strength of multiple electrolytic copper foil samples. The high temperature tensile strength should have a gradient; (2) Using EBSD to test the crystal structures of samples with different high temperature tensile strengths after annealing at room temperature and high temperature; (3) Draw the normal and annealed crystal structure maps corresponding to different high-temperature tensile strengths, and establish the corresponding relationship between the high-temperature tensile constant and the grain size change rate; (4) The high temperature tensile strength of the electrolytic copper foil can then be directly tested to quickly determine the stability of its crystal structure.

2. The test method for efficiently evaluating the crystal structure stability of electrolytic copper foil according to claim 1, characterized in that: The high temperature tensile strengths of different electrolytic copper foil samples in the step (1) are respectively 200-210 MPa, 211-220 MPa, 221-230 MPa, and 231-240 MPa.

3. The test method for efficiently evaluating the crystal structure stability of electrolytic copper foil according to claim 1, characterized in that: The high temperature tensile strength test condition in step (1) is that the copper foil sample strip has a width of 12.7 mm and a length of 100 mm, and the tensile strength test is performed after being kept at 180° C. for 5 minutes in a high temperature universal tensile testing machine oven.

4. The test method for efficiently evaluating the crystal structure stability of electrolytic copper foil according to claim 1, characterized in that: The high temperature annealing condition in step (2) is 180° C. for 1 hour.

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