JP5588607B2 - Electrolytic copper foil and method for producing the electrolytic copper foil - Google Patents

Description

  The present invention relates to an electrolytic copper foil, a surface-treated copper foil using the electrolytic copper foil, a method for producing the electrolytic copper foil, and a copper-clad laminate using the surface-treated copper foil. Particularly, the present invention relates to an electrolytic copper foil having a low profile and a high mechanical strength, a method for producing the same, and the like.

  Electrolytic copper foil has been required to improve its strength in various fields including tape automated bonding (hereinafter referred to as “TAB”) products, negative electrode current collectors for lithium secondary batteries, and the like. . For example, in a TAB product, a plurality of terminals of an IC chip are directly bonded to inner leads (flying leads) arranged in a device hole located in a substantially central part of the product. Bonding at this time is performed by applying current and heating instantaneously and applying a certain bonding pressure using a bonding apparatus (bonder). At this time, there is a problem that the inner lead obtained by etching the electrolytic copper foil is stretched by being stretched by the bonding pressure. Therefore, there is a problem in terms of strength even when the line width of the inner lead is reduced.

  Moreover, when using copper foil as a constituent material of the negative electrode current collector for a lithium secondary battery, there were two problems due to mechanical strength. First, it is a problem in the manufacturing process of the negative electrode current collector for a lithium secondary battery. For example, a thermal history at a fairly high temperature is received in the activator loading process. As a result, the softening of the strength of the electrolytic copper foil used is remarkable and the durability is inferior, so that it is impossible to supply a long-life lithium secondary battery. In addition, when an electrolytic copper foil with low mechanical strength is used as a constituent material of a negative electrode current collector for a lithium secondary battery, deformation of the negative electrode current collector for a lithium secondary battery during charge / discharge increases, Naturally, it is impossible to achieve a long life, and there is a concern about the safety of the battery. This is particularly noticeable when a negative electrode active material containing silicon or tin that is significantly expanded during charging is used.

On the other hand, in response to the recent demands for miniaturization and weight reduction of electronic and electrical equipment, circuit formation corresponding to miniaturization and high functionality in a limited mounting space is required for printed wiring. Required for board. In such a printed wiring board, it is necessary to form a circuit with a finer circuit and a higher density. Therefore, in order to obtain such a fine pitch circuit, it is necessary to reduce the roughness of the bonding surface of the electrolytic copper foil with the base material and to shorten the overetching time. As a result, in recent years, the use of low profile electrolytic copper foil has become common. Also in the field of ordinary wiring boards, it has been required to increase the mechanical strength of the electrolytic copper foil in order to improve the handleability of the thinned electrolytic copper foil and copper clad laminate. Specifically, a tensile strength exceeding 70 kgf / mm ² and a mechanical strength equivalent to that of a phosphor bronze hard material have been desired for the electrolytic copper foil.

  In order to meet the above demands, various studies have been conducted as electrolytic copper foils having a low profile bonded surface with a base material and excellent mechanical strength. For example, the invention disclosed in Patent Document 1 has a low rough surface electrolytic copper foil that has a low rough surface that can be practically used for printed wiring board applications and negative electrode current collector applications for lithium secondary batteries, and has excellent fatigue flexibility, Specifically, the rough surface roughness Rz is 2.0 μm or less, the rough surface has a rough surface with no unevenness and is uniformly reduced in roughness, and the elongation at 180 ° C. is 10.0%. The object is to provide a low-roughened surface electrolytic copper foil as described above. Then, using a sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, a titanium drum is used as an insoluble anode made of a titanium plate coated with a white metal element or its oxide element, and a cathode facing the anode, and a direct current is applied between the two electrodes. A method for producing electrolytic copper foil is disclosed. In this manufacturing method, the rough surface roughness Rz is 2.0 μm or less by allowing the electrolyte solution to contain an oxyethylene surfactant, polyethyleneimine or a derivative thereof, a sulfonate salt of an active organic sulfur compound, and a chloride ion. It is described that the rough surface has a rough surface with no unevenness and has a uniformly roughened surface, and an elongation at 180 ° C. of 10.0% or more can be obtained. Yes.

Furthermore, when the Example of this patent document 1 is seen, the surface roughness (Rz) of the precipitation surface of the obtained electrolytic copper foil is 0.9 micrometer-2.0 micrometers, and the value of a normal state elongation rate is 10%-18%, The elongation value at 180 ° C. is 10% to 20%, the normal tensile strength value is 340 MPa to 500 MPa (34.66 kgf / mm ^{2 to} 50.99 kgf / mm ² ), and the tensile strength value at 180 ° C. is 180 MPa. It is disclosed to be ˜280 MPa (18.35 kgf / mm ^{2 to} 28.55 kgf / mm ² ). Furthermore, it is disclosed that the glossiness [Gs (85 °)] of the deposited surface of the electrolytic copper foil in the width direction is 120 to 132.

  In addition, the invention disclosed in Patent Document 2 is a low-roughened electrolytic copper foil having a roughened surface with a low roughness, a low decrease in tensile strength with time or heat treatment, and an excellent elongation at high temperatures, and its The object is to provide a manufacturing method. Then, five additives of hydroxyethyl cellulose, polyethyleneimine, acetylene glycol, sulfonate of active organic sulfur compound and chloride ion are present in the electrolytic solution composed of sulfuric acid-copper sulfate aqueous solution, and an electrolytic copper foil is manufactured using this. doing. The rough surface roughness Rz of the electrolytic copper foil obtained here is 2.5 μm or less, and the tensile strength at 25 ° C. measured within 20 minutes from the completion of electrodeposition is 500 MPa or more. Furthermore, the rate of decrease in tensile strength at 25 ° C. measured after 300 minutes from the completion of electrodeposition is 10% or less, and the tensile strength at 25 ° C. measured after heat treatment at 100 ° C. for 10 minutes from the completion of electrodeposition. Discloses a low rough surface electrolytic copper foil having a decrease rate of 10% or less and an elongation at 180 ° C. of 6% or more.

And if the Example of this patent document 2 is seen, more specific content can be grasped | ascertained. That is, an electrolyte composed of a sulfuric acid-copper sulfate aqueous solution of sulfuric acid (H ₂ SO ₄ ): 100 g / L, copper sulfate pentahydrate (CuSO ₄ .5H ₂ O): 280 g / L is used as a basic solution, and as an additive. Titanium cathode drum which is an insoluble anode and cathode made of titanium, to which hydroxyethyl cellulose, polyethyleneimine, sodium 3-mercapto-1-propanesulfonate, acetylene glycol and hydrochloric acid are added and this electrolyte is coated with a white metal oxide And an electrolytic copper foil obtained by electrodeposition at an electrolytic current density of 40 A / dm ² and an electrolyte temperature of 40 ° C. is disclosed. This electrolytic copper foil has a thickness of 18 μm, a surface roughness (Rz) of the deposited surface of 1.5 μm to 2.3 μm, and a normal tensile strength of 650 MPa to 900 MPa (66.28 kgf / mm ^{2 to} 91.77 kgf / mm). ² ), it is described that the rate of decrease in tensile strength after heating at 100 ° C. for 10 minutes was 0% to 7.7%.

  According to said Example, the precipitation surface of the electrolytic copper foil manufactured using these manufacturing methods is a low profile. The low profile level is excellent from the viewpoint of a conventional low profile electrolytic copper foil, and can be effective in forming a fine pitch circuit. It is also disclosed that mechanical strength superior to that of conventional electrolytic copper foil can be obtained. In addition, although it describes for convenience, the low profile in the copper foil for printed wiring boards is used in the meaning that the unevenness | corrugation in the joining interface with the insulating layer constituent material of copper foil is low.

Further, Patent Document 3 discloses a controlled low profile electrodeposited copper foil. Specifically, an electrodeposited copper foil having a particle structure with essentially no cylindrical particles and twin boundaries and an average particle size of up to 10 microns, the particle structure being substantially uniform and random Discloses a controlled low profile electrodeposited copper foil having a grain structure oriented in This electrodeposited copper foil has a maximum tensile strength at 23 ° C. in the range of 87,000 to 120,000 psi (61.18 kgf / mm ^{2 to} 84.38 kgf / mm ² ), and a maximum tensile strength at 180 ° C. of 25, It is disclosed that it has physical characteristics such as being in the range of 000 to 35,000 psi (17.58 kgf / mm ^{2 to} 24.61 kgf / mm ² ).

Looking at the description in Patent Document 3, FIG. 4 shows a micrograph of a cross section of the copper foil according to the invention at a magnification of 1600 times. As can be understood from FIG. 4, the electrodeposited copper foil disclosed in Patent Document 3 is described as having a particle structure having essentially no cylindrical particles and twin boundaries and an average particle size of up to 10 microns. As can be seen, it has a particle size of 10 microns or less, but has crystal particles that can be observed at a magnification of 1600 times. Strictly speaking, in the specification of Patent Document 3, an electrolytic copper foil whose maximum tensile strength at 23 ° C. exceeds 100,000 psi (70.32 kgf / mm ² ) is not specifically disclosed.

  Among the conventional techniques described above, particularly in TAB applications and negative electrode current collector applications for lithium secondary batteries, there is a movement to use a Corson alloy foil even though this may lead to a slight increase in cost.

JP 2004-263289 A JP 2004-339558 A JP-A-7-188969

However, Corson alloy foil is expensive to manufacture and may have a high electrical resistance as a material for forming a printed circuit, so it is considered that it cannot be widely used in the printed wiring board field. For this reason, in recent years, it has been demanded that an electrolytic copper foil with a low production cost has mechanical strength equivalent to that of a Corson alloy foil and has a characteristic of low electrical resistance, and it is required to provide a high strength electrolytic copper foil as an alternative. It has become. That is, what is required is an electrolytic copper foil that has tensile strength, elongation, electrical resistance, breaking strength, and the like that of Corson alloy foil or higher. In the case of Corson alloy foil, the tensile strength is normally about 90.00 kgf / mm ^{2 to} 99.00 kgf / mm ^{2 and} hardly changes even after heat treatment at 180 ° C. for 60 minutes, rather precipitation hardening occurs. May rise. The elongation is 5.0% to 6.0% in a normal state and 3.5% to 7.0% after heat treatment at 180 ° C. for 60 minutes. Here, the reason why the elongation rate decreased is that the tensile strength increased due to precipitation hardening by heating, and the hardness increased.

In the case of the electrolytic copper foil disclosed in Patent Document 1, the surface roughness (Rz) of the deposited surface of the electrolytic copper foil is in the range of 0.9 μm to 2.0 μm and a good low profile surface can be formed. The value of the normal tensile strength is in the range of 340 MPa to 500 MPa (34.66 kgf / mm ^{2 to} 50.99 kgf / mm ² ). Therefore, it is difficult to say that it has the same mechanical strength as Corson alloy foil.

In the case of the electrolytic copper foil disclosed in Patent Document 2, the surface roughness (Rz) of the deposition surface is in the range of 1.5 μm to 2.3 μm, and has a low profile surface that is good to some extent. However, the normal tensile strength is in the range of 650 MPa to 900 MPa (66.28 kgf / mm ^{2 to} 91.77 kgf / mm ² ), indicating that a value of less than 70 kgf / mm ² is obtained. Moreover, as a result of the inventors conducting a trace experiment (used in the following “Comparative Example”) based on the example of Patent Document 2, the tensile strength of the obtained electrolytic copper foil is 58 kgf / mm. ^{It was} about ^2, and a value exceeding the lower limit value 66.28 kgf / mm ² described in the claims was not obtained. That is, the method for producing an electrolytic copper foil disclosed in Patent Document 2 lacks production stability, and it is considered that the quality of the product obtained is large. In order to say that the mechanical strength is as high as that of Corson alloy foil, it is essential to be able to stably produce an electrolytic copper foil having a tensile strength value exceeding 70 kgf / mm ^2. The method seems to be difficult.

Furthermore, in the case of the electrolytic copper foil disclosed in Patent Document 3, there is no columnar particle and twin boundary, and the crystal structure having an average crystal particle diameter of 10 μm or less (according to FIG. 4 of Patent Document 3, the crystal grain size is 2 μm). It can be interpreted that the maximum tensile strength at 23 ° C. was within the range of 87,000 to 120,000 psi (61.18 kgf / mm ^{2 to} 84.38 kgf / mm ² ). However, here, a tensile strength comparable to that of a Corson alloy foil having a maximum tensile strength exceeding 90.00 kgf / mm ² is not obtained. Further, the surface roughness referred to as a low profile of the electrolytic copper foil disclosed in Patent Document 3 is described in Paragraphs 0027 to 0029 of Patent Document 3. In Patent Document 3, “R _tm ” is used to display the surface roughness. As described in paragraph 0029 of the specification of Patent Document 3, this value is described as “the R _tm of a thin foil tends to be smaller than that of a thick foil”, and the same tendency as that of a conventional electrolytic copper foil. It has been revealed that In the case of the foil disclosed in Patent Document 3, it is described that the maximum tensile strength at 180 ° C. is in the range of 25,000 to 35,000 psi (17.58 kgf / mm ^{2 to} 24.6 kgf / mm ² ). . In the case of the electrolytic copper foil disclosed in Patent Document 3, the tensile strength after heating at 180 ° C. × 60 minutes is not disclosed, but the tensile strength after heating is 80% or less of the normal tensile strength. descend. Considering this point, it cannot be a substitute for Corson alloy foil.

  As can be understood from the above, the present invention is an electrolytic copper foil as a printed wiring board material provided with a fine pitch circuit, and the use of a Corson alloy foil is being investigated. An object of the present invention is to provide an electrolytic copper foil having high strength and low electrical resistance that can be used as a body constituent material.

  Therefore, as a result of intensive studies, the inventors of the present invention have been able to increase the strength equivalent to that of the Corson alloy foil by adopting the electrolytic copper foil described below. In addition, by adopting the manufacturing method described below, it was possible to produce an electrolytic copper foil having high strength equivalent to that of Corson alloy foil.

Electrolytic copper foil according to the present invention: The electrolytic copper foil according to the present invention is an electrolytic copper foil obtained by electrolyzing a copper electrolyte, wherein the electrolytic copper foil contains 110 ppm to 400 ppm of sulfur and 280 ppm to 650 ppm of chlorine. In addition, the electrical conductivity is 49.3% IACS or more , and the tensile strength value in a normal state is 70 kgf / mm ² or more.

Surface-treated copper foil according to the present invention: The surface-treated copper foil according to the present invention comprises one or more of roughening treatment, rust prevention treatment, and silane coupling agent treatment on the surface of the above-described electrolytic copper foil. It is characterized by having given.

Manufacturing method of electrolytic copper foil according to the present invention: The manufacturing method of the electrolytic copper foil according to the present invention is a method of manufacturing the above-described electrolytic copper foil by an electrolytic method using a sulfuric acid-based copper electrolytic solution, and the sulfuric acid The system copper electrolyte contains the following additive A to additive C and has a chlorine concentration of 40 ppm to 80 ppm.

Additive A: Compound having a structure in which a heterocyclic ring contains a benzene ring and N and simultaneously having a mercapto group bonded thereto, Compound having a 5-membered ring structure in which one or more N atoms are bonded to a heterocyclic ring and SH group is simultaneously bonded, One or more compounds selected from thiourea compounds.
Additive B: sulfonate salt of active sulfur compound.
Additive C: ammonium salt polymer having a cyclic structure.

Copper-clad laminate according to the present invention: A copper-clad laminate according to the present invention is obtained by bonding the above-mentioned surface-treated electrolytic copper foil with an insulating layer constituting material. It should be noted that the concept of the copper-clad laminate referred to here includes both rigid copper-clad laminate and flexible copper-clad laminate.

  Since the electrolytic copper foil which concerns on this invention is comprised by the above-mentioned precipitation order crystal particle of nm order, it comes to have very big mechanical strength by the refinement | miniaturization effect of a crystal grain. Moreover, the mechanical strength of the electrolytic copper foil according to the present invention is almost the same as the normal mechanical strength even after heating at 180 ° C. for 60 minutes. And since the particle diameter of the crystal | crystallization is fine, it has the low profile precipitation surface of the level exceeding the conventional low profile electrolytic copper foil.

  And, using the electrolytic copper foil according to the present invention, surface treatment for the purpose of rust prevention treatment, roughening treatment for improving adhesion with the base resin, silane coupling agent treatment, etc. To give a surface-treated copper foil. Therefore, this surface-treated copper foil also has good mechanical strength and a smooth surface.

  Moreover, even if the copper clad laminated board obtained using the said surface-treated electrolytic copper foil is thin, the bending and deformation | transformation at the time of handling are few, and it becomes easy to handle with the extremely big mechanical strength of electrolytic copper foil.

  Furthermore, the method for producing an electrolytic copper foil according to the present invention is characterized by the composition of the copper electrolyte used. This copper electrolyte is excellent in solution stability and withstands long-term continuous use, so that it is economically superior.

  Hereinafter, the preferred embodiments of the electrolytic copper foil, the surface-treated copper foil, the electrolytic copper foil manufacturing method, and the copper-clad laminate according to the present invention will be described in order.

Form of electrolytic copper foil according to the present invention: The electrolytic copper foil according to the present invention is an electrolytic copper foil obtained by electrolyzing a copper electrolyte. First, components that are included in the electrolytic copper foil according to the present invention and that are not included in a general electrolytic copper foil will be described.

The electrolytic copper foil according to the present invention contains 110 ppm to 400 ppm of sulfur, 280 ppm to 650 ppm of chlorine, has an electric conductivity of 49.3% IACS or more , and has a tensile strength value of 70 kgf / mm ² or more in a normal state. It is the first feature to be characterized by being. It is impossible to obtain mechanical properties close to Corson alloy foil with a copper component close to pure copper, even from metallurgical common sense. Therefore, the mechanical strength was improved by including sulfur in the crystal structure of the electrolytic copper foil and setting the amount of the component to an appropriate level. It should be noted that the unit “ppm” used to display the content of the component is synonymous with “mg / l”, just in case.

  Sulfur contained in the electrolytic copper foil is caused by components contained in the electrolytic solution used in the production method described later. When the sulfur content is less than 110 ppm, the grain size of the crystal grains formed by electrolytic deposition does not reach the nm level, and the electrolytic copper foil having high mechanical strength is not obtained. On the other hand, when the sulfur content exceeds 400 ppm, the deposited structure of the electrolytic copper foil is likely to cause embrittlement, and the elongation rate is reduced. Therefore, a raw material for producing a flexible copper-clad laminate that requires bending resistance characteristics As inappropriate.

Moreover, it is preferable that the said electrolytic copper foil contains chlorine in the range of 280 ppm-650 ppm as the structural component . This chlorine is caused by the components contained in the electrolytic solution used in the production method described later. Here, when chlorine as a constituent component of the electrolytic copper foil is less than 150 ppm, the grain size of the crystal grains formed by electrolytic deposition is unlikely to be in the nm level, and the electrolytic copper foil having stable high mechanical strength is Don't be. Moreover, when the chlorine concentration in the electrolytic copper foil becomes low, the mechanical strength variation tends to increase when the electrolytic copper foil is stored for a long period of time. On the other hand, when chlorine as a constituent component of the electrolytic copper foil exceeds 650 ppm, the roughness of the deposited surface of the obtained electrolytic copper foil becomes large, and it becomes difficult to produce a low profile electrolytic copper foil. In the chlorine concentration range (280 ppm to 650 ppm), since the grain size of the precipitated crystal grains formed by electrolytic deposition is stabilized at the nm level, the low profile electrolytic copper foil having high mechanical strength and long The fluctuation in mechanical strength when stored for a period is significantly reduced.

And it is also preferable that the electrolytic copper foil which concerns on this invention contains carbon as the structural component. By containing carbon, the strength of the electrolytic copper foil can be increased, and at the same time, the drilling performance by laser processing is improved. This carbon is also attributed to the components contained in the electrolytic solution used in the production method described later. The carbon contained in the electrolytic copper foil is preferably in the range of 250 ppm to 470 ppm, more preferably 250 ppm to 450 ppm. When the carbon content is less than 250 ppm, the strength of the electrolytic copper foil cannot be increased and it is difficult to improve the drilling performance by laser processing. On the other hand, when the carbon concentration exceeds 470 ppm, the electrolytic copper foil is easily embrittled, the elongation rate is rapidly reduced, and at the same time, the electric resistance is remarkably increased, so that it is difficult to substitute for the Corson alloy foil. This is because a more preferable carbon concentration range (250 ppm to 450 ppm) is excellent in the balance between high strength and elongation as an electrolytic copper foil and does not cause a significant increase in electrical resistance stably.

Further, the electrolytic copper foil preferably has nitrogen as a constituent component in a range of 40 ppm to 180 ppm, more preferably 40 ppm to 120 ppm . This nitrogen is attributed to the components contained in the electrolytic solution used in the production method described later, and seems to have an effect of promoting the incorporation of sulfur components into the electrolytic copper foil. Here, when an electrolytic solution in which nitrogen as a constituent component of the electrolytic copper foil is less than 40 ppm is used, it is difficult to incorporate an appropriate amount of the sulfur component with respect to the electrolytic copper foil to be manufactured. When the nitrogen content of the steel exceeds 180 ppm, the sulfur content also exceeds 400 ppm, and the deposited structure of the electrolytic copper foil tends to cause embrittlement and the elongation rate decreases. It becomes unsuitable as a manufacturing raw material for laminates. If it is a more preferable nitrogen concentration range (40 ppm to 120 ppm), the content of sulfur in the electrolytic copper foil does not exceed 400 ppm and easily embrittles even if there are some fluctuations in the production conditions of the electrolytic copper foil. A deposited structure of the electrolytic copper foil is not obtained.

And this electrolytic copper foil is equipped with the electroconductivity that electrical conductivity is 49.3% IACS or more . In addition, it is also possible to make the electroconductivity of the said electrolytic copper foil 55% IACS or more by managing manufacturing conditions most appropriately. Here, the electrical conductivity in the case of a commercially available Corson alloy foil is in the range of 35% IACS to 60% IACS. Therefore, in the case of the electrolytic copper foil according to the present invention, the electric conductive performance equal to or higher than that of the Corson alloy foil is provided. Here, the upper limit of the electrical conductivity of the electrolytic copper foil according to the present invention is not specified. The reason is that the value of electrical conductivity varies depending on the content of components other than copper, the difference in the grain size of the deposited copper crystal grains, and the like. Empirically speaking, the upper limit is about 78% IACS. The conductivity (% IACS) mentioned here is the same as the conductivity of other substances at the same temperature and volume when the conductivity of standard annealed copper (specific resistance 1.7241 μΩ · cm · 20 ° C.) is 100%. This is expressed as a ratio. The larger the value, the better the electrical conductivity.

Moreover, it becomes an electrolytic copper foil provided with the tensile strength in the high normal state of 70 kgf / mm < ² > or more by containing sulfur, carbon, etc. in the precipitation crystal structure of an electrolytic copper foil in the above ranges. This high mechanical strength mainly contributes to the effect of crystal grain refinement. For example, the fracture in the tensile test is considered to be that microcracks occur at the edge of the sample piece under test, and the tensile stress concentrates on the microcracks, causing crack propagation and leading to fracture. The crack propagation at this time is mainly propagation along the crystal grain boundary. Therefore, if fine crystal grains are provided, the propagation path of cracks becomes long and the breaking stress increases.

  And as a mechanical characteristic of the electrolytic copper foil which concerns on this invention, the elongation rate in a normal state becomes the range of 3%-15%. If the value of the elongation rate in this normal state is 3% or more, the occurrence of foil cracks can be prevented even when a through-hole substrate is formed by drilling a copper-clad laminate with a mechanical drill. On the other hand, the upper limit of the normal elongation is an average of actually measured values in consideration of the performance of the electrolytic copper foil according to the present invention, and is about 15% empirically.

  The crystal structure that affects the mechanical properties of the electrolytic copper foil according to the present invention in the normal state includes crystal grains grown from the precipitation start surface toward the precipitation end surface, and the average minor axis length of the crystal grains is 30 nm to The length of 110 nm and the average major axis is preferably 80 nm to 400 nm. Here, “crystal grains grown from the precipitation start surface toward the precipitation end surface” means vertically long crystal grains that have started growing from the precipitation start surface. However, the crystal grains mentioned here have an average minor axis length of 30 nm to 110 nm and an average major axis length of 80 nm to 400 nm, and therefore cannot be confirmed as crystal grains unless the magnification exceeds 10,000 times. Preferably, an observation magnification of 30000 times or more is used. Therefore, the FIB method using a focused ion beam obtained by squeezing a beam obtained by accelerating gallium (Ga) ions by an electric field is sputter-etched on the cross section of the electrolytic copper foil, and the crystal grains appearing on the etched surface are scanned. It is preferable to observe using an electron microscope.

When the electrolytic copper foil has such a fine crystal grain size as described above, a high tensile strength of 70 kgf / mm ² or more and the above-described elongation can be obtained. And there are elements that are affected by the content of components such as sulfur, carbon, chlorine, etc. in the electrolytic copper foil, electrolysis conditions such as electrolysis current, liquid temperature, etc., but a tensile strength of 88 kgf / mm ² or more is obtained under normal conditions. In this case, it is preferable to set the average minor axis length to 30 nm to 60 nm and the average major axis length to 80 nm to 150 nm.

In addition, as a feature of the electrolytic copper foil according to the present invention, the size of crystal grains is in the range of 1 μm or less even after heating at 180 ° C. for 60 minutes. Generally, in the case of a rolled copper foil, the value of the normal tensile strength can be increased by increasing the degree of processing. However, when such a rolled copper foil that has been strengthened plastically is heated, it tends to recrystallize due to the reorganization of the internal transition even at low temperatures, and tends to soften easily as an annealing effect. On the other hand, in the case of an electrolytic copper foil, as an original property, softening due to low-temperature annealing hardly occurs. In particular, in the case of an electrolytic copper foil containing a predetermined amount of sulfur, carbon, and chlorine as described above, even after heating at 180 ° C. for 60 minutes, the crystal grains grown from the precipitation start surface to the precipitation end surface And a precipitation structure composed of crystal grains having an average minor axis length of 25 nm to 120 nm and an average major axis length of 100 nm to 500 nm. From this, it can be understood that the electrolytic copper foil according to the present invention does not greatly decrease the tensile strength value even when heated at 180 ° C. for 60 minutes.

That is, the electrolytic copper foil according to the present invention, 180 in after the heat of ° C. × 60 minutes, it can be said that the strength values of the tensile after heating can be maintained more than 85% of the normal tensile strength values. As described above, the decrease in the tensile strength after heating is small because the crystal grains of the electrolytic copper foil according to the present invention are fine on the order of nm, and the variation in the crystal grain size is small, which is included during electrolysis. This is because the distribution of the additive component of the electrolyte solution to the grain boundaries is uniform. Since this additive component functions as a diffusion barrier for metallic copper during heating and suppresses the enlargement of crystal grains, it is considered that the effect of crystal grain refinement can be maintained even after heating. Then, the intensity values normal pull strength values tensile after heating, if at least 90% or more, as a replacement for Corson alloy foil, more preferably. On the other hand, in the case of the conventional electrolytic copper foil, the value of the tensile strength after heating at 180 ° C. for 60 minutes is 60% or less of the value of the normal tensile strength. The reason why the heating condition of 180 ° C. × 60 minutes is selected here is that it is close to the temperature condition of the heating press employed in the production of a general copper-clad laminate.

Moreover, the electrolytic copper foil which concerns on this invention can maintain the value of the normal state tensile strength after progress for 30 days after manufacture at 70 kgf / mm < ² > or more. The mechanical properties of the electrolytic copper foil change over time even after storage at room temperature, stabilize after 30 days after manufacture, and stabilize significantly after storage at room temperature. There is a tendency to disappear. Therefore, if the normal tensile strength after 30 days from the production is measured, long-term quality assurance of the electrolytic copper foil according to the present invention becomes practically possible.

  And the value of the elongation rate after the heating for 180 degreeC x 60 minutes of the electrolytic copper foil which concerns on this invention is 3.0% or more, and is 4.0% or more in a more preferable embodiment. In the conventional electrolytic copper foil excellent in low temperature annealing property, the value of elongation becomes larger than the value of normal elongation after heating at 180 ° C. for 60 minutes. On the other hand, the electrolytic copper foil according to the present invention shows a substantially equivalent value when the value of the elongation after heating at 180 ° C. for 60 minutes is compared on the basis of the value of the normal elongation.

The above-described high tensile strength and elongation of the electrolytic copper foil according to the present invention are mechanical characteristics that can be exhibited because of the fineness of the crystal grains. Further, this crystal structure is such that the “average major axis length” and “average minor axis length” of the normal crystal particles in the cross section near the precipitation surface are [average minor axis length] / [average major axis]. It is preferable to have a relationship of [length] = 0.1 to 0.5. Here, the balance between the average major axis length and the average minor axis length of the crystal particles is the viewpoint that the high strength characteristics of the electrolytic copper foil composed of the crystal particles and the low profile performance of the precipitation surface can be obtained stably at the same time. From is important. Here, when [average minor axis length] / [average major axis length] is less than 0.1, the precipitation surface of the obtained electrolytic copper foil cannot be lowered in profile, and the surface roughness of the precipitation surface can be reduced. Since the thickness (Rzjis) exceeds 2.0 μm, the electrolytic copper foil is difficult to form a fine pitch circuit. On the other hand, when [average minor axis length] / [average major axis length] exceeds 0.5, the shape of the crystal particles approaches a square shape, making it difficult to increase the strength.

  And since the crystal grain which comprises the crystal structure of the electrolytic copper foil which concerns on this invention is fine and uniform, the uneven | corrugated shape of the precipitation surface becomes smooth. Glossiness was adopted as an index indicating the smoothness of the deposited surface of the electrolytic copper foil according to the present invention. The glossiness [Gs (60 °)] of the precipitation surface is preferably 100 or more. In the examples described later, the glossiness [Gs (60 °)] is 100 or more.

  In addition, since the fineness of the crystal grains described above is provided, the surface roughness of the deposited surface of the electrolytic copper foil according to the present invention is extremely low, and the surface becomes a low profile surface. By providing the fine crystal grains as described above, it is possible to form a precipitation surface having a surface roughness in the range of Rzjis = 0.40 μm to 1.80 μm.

  There is no particular limitation on the thickness of the electrolytic copper foil described above. Considering a product generally produced as an electrolytic copper foil, it is sufficient to consider it as an electrolytic copper foil having a thickness in the range of 7 μm to 400 μm, particularly 10 μm to 40 μm.

Form of surface-treated copper foil according to the present invention: The surface-treated copper foil according to the present invention is one or two of roughening treatment, rust-proofing treatment, and silane coupling agent treatment on the surface of the above-described electrolytic copper foil. The above surface treatment is performed. The surface treatment referred to here is roughening treatment, antirust treatment, silane applied to the surface of the electrolytic copper foil for the purpose of imparting adhesive strength, chemical resistance, heat resistance, etc. in consideration of the required properties for each application. Coupling agent treatment and the like.

  The roughening treatment referred to here is a treatment for physically improving the adhesion between the surface-treated copper foil and the insulating layer constituting material, and is generally performed on the deposition surface of the electrolytic copper foil. More specifically, a method of adhering and forming fine metal particles on the surface (mainly the deposition surface side) of the electrolytic copper foil or forming a roughened surface by an etching method is employed. When fine metal particles are deposited on the surface of the electrolytic copper foil, the burn plating process for depositing and attaching the fine metal grains and the covering plating process for preventing the fine copper grains from falling off are combined. It is common to apply.

  Next, the rust prevention treatment will be described. In this rust prevention treatment, it is provided as a coating layer for preventing the surface of the surface-treated copper foil from being oxidized and corroded during the production process of the copper clad laminate, the printed wiring board and the like. There are no problems with the rust-proofing treatment, either organic rust-proofing using benzotriazole or imidazole, or inorganic rust-proofing such as zinc, chromate or zinc alloy. A method may be selected. And in the case of organic rust prevention, it is possible to employ | adopt formation methods, such as the immersion coating method of the organic rust preventive agent, the shower ring coating method, and the electrodeposition method. In the case of inorganic rust prevention, it is possible to deposit an antirust element on the surface of the electrolytic copper foil layer using an electrolysis method, an electroless plating method, a sputtering method, a displacement precipitation method, or the like.

  And a silane coupling agent process is a process for improving the adhesiveness of surface-treated copper foil and an insulating-layer constituent material chemically after a roughening process, a rust prevention process, etc. are complete | finished. The silane coupling agent used for the silane coupling agent treatment here is not particularly limited. Arbitrarily selected from epoxy-based silane coupling agents, amino-based silane coupling agents, mercapto-based silane coupling agents, etc. in consideration of the properties of the insulating layer constituent material to be used and the plating solution used in the printed wiring board manufacturing process Can be used. And in order to form a silane coupling agent layer, methods, such as dip coating, showering coating, and electrodeposition, can be employ | adopted using the solution containing a silane coupling agent.

Manufacturing method of electrolytic copper foil according to the present invention: The manufacturing method of the electrolytic copper foil according to the present invention is a method of manufacturing the above-described electrolytic copper foil using an electrolytic method using a sulfuric acid-based copper electrolytic solution. The composition of the sulfuric acid-based copper electrolyte used here is characteristic. This sulfuric acid-based copper electrolyte preferably contains an additive A to an additive C described below and has a chlorine concentration of 40 ppm to 80 ppm. The additives A to C and chlorine will be described in this order. In addition, the copper concentration in the sulfuric acid-type copper electrolyte said here uses 50 g / L-120 g / L, More preferably, the range of 50 g / L-80 g / L is used. The free sulfuric acid concentration is assumed to be in the range of 60 g / L to 250 g / L, more preferably 80 g / L to 150 g / L.

The additive A will be described. This additive A includes “a compound having a structure in which a heterocyclic ring contains a benzene ring and N at the same time and a mercapto group is bonded”, and “a five-membered ring in which at least one N is included in the heterocyclic ring and an SH group is simultaneously bonded. One or more compounds selected from “compound having a structure” and “thiourea compound”. This additive A is uniformly distributed at the grain boundaries during electrodeposition of the electrolytic copper foil, is excellent in the effect of promoting the refinement of the crystal grains of the deposited copper, and contributes to the stabilization of the production of the electrolytic copper foil. As a result, an electrolytic copper foil having a high tensile strength is obtained. Conventionally, thiourea is known as an additive exhibiting the same effects as these additives A. When this thiourea is used alone without being combined with additive B and additive C, a decomposition product with a low molecular weight is generated in the copper electrolyte, so that it is difficult to remove it. It is not preferable because it is included or the precipitation state of copper becomes unstable.

  On the other hand, “a compound having a structure in which a heterocyclic ring contains a benzene ring and N and simultaneously a mercapto group is bonded” as additive A has a stable chemical structure called a benzene ring, and further contains N. Since it has a heterocyclic structure, it is preferable that it has a stable structure in a copper sulfate solution, is difficult to decompose, and does not easily generate a low molecular weight decomposition product. If the mercapto group is bonded to the heterocyclic ring and the sulfone group is bonded to the benzene ring, the polarity of the intramolecular electrons is increased and the solution is easily dissolved in an aqueous solution. This is preferable.

  Specifically, the “compound having a structure in which the heterocyclic ring as additive A includes a benzene ring and N and simultaneously has a mercapto group bonded” is an imidazole compound, a thiazole compound, or a tetrazole compound. . Further, triazole compounds and oxazole compounds are also included here.

  It is more preferable to use a chemical structure having a sulfone group bonded to the benzene ring of the additive A. A compound having a chemical structure in which a sulfone group is bonded to a benzene ring exhibits extremely good stability in a sulfuric acid-based copper electrolyte. As a result, the property change of the solution is small, the electrolytic state is stabilized, and the solution life is also prolonged.

  Hereinafter, more specifically speaking, the additive A having the above-described structure is 2-mercapto-5-benzimidazolesulfonic acid (hereinafter referred to as “2M-5S”), 3 (5-mercapto-1H— It is preferable to use tetrazolyl) benzenesulfonate (hereinafter referred to as “MSPMT-C”) or 2-mercaptobenzothiazole (hereinafter referred to as “WM”). Hereinafter, the structural formula of 2M-5S is shown in Chemical Formula 1, the structural formula of MSPMT-C is shown in Chemical Formula 2, and the structural formula of WM is shown in Chemical Formula 3. And when actually using these compounds, they can be used in the state of readily water-soluble salts that are easily available, such as Na salts as used in the examples described later.

  Next, the “compound having a 5-membered ring structure in which one or more N is included in the heterocyclic ring and SH group is simultaneously bonded” as the additive A is an imidazole compound or a thiol compound. More specifically, these compounds are represented by 2-mercapto-imidazole (hereinafter referred to as “2MI”) shown as the following chemical formula 4, 2-thiazoline-2-thiol (hereinafter referred to as “2TT” shown as the chemical formula 5). ").

  Further, thiourea or its derivative as additive A can be used in combination with additive B and additive C. Among these, “a thiourea compound having a functional group having 2 or more carbon atoms” is preferably used. For example, in a thiourea compound having an alkane group having 2 or more carbon atoms at both ends, the polarity of thiourea is weakened by the alkane group. Therefore, it has a [= S] structure that improves the reactivity with copper ions, and hardly exhibits a decomposition behavior like thiourea even during an electrolytic reaction. Therefore, if a thiourea compound that does not easily decompose during these electrolytic reactions is used, problems that occur when thiourea is used are less likely to occur.

  Specifically, “a thiourea compound having an alkane group having 2 or more carbon atoms at both ends” is specifically exemplified. N, N′-diethylthiourea (hereinafter referred to as “EUR”) having excellent chemical structure stability. .) Is preferably used. The structural formula of EUR is shown in Chemical Formula 6 below. As can be understood from the chemical structural formula of this EUR, the chemical structure arrangement of N and S is the same as that of thiourea. Moreover, it is thought that by having an ethyl group at both ends, the activity of the terminal group is weak and the stability in the electrolytic solution is improved.

  Two or more of the additives A described above can be selectively used, and these can be used in combination. Even if different components of additive A are used in combination, there is no change in the effect as additive A. Rather, by using it as a mixture, as an electrolytic solution according to the copper concentration, liquid temperature, etc. in the sulfuric acid-based copper electrolytic solution It may be easy to adjust the solution properties.

  Therefore, it is preferable that the concentration of the additive A in the sulfuric acid-based copper electrolyte (total concentration when two or more types are used) is 1 ppm to 50 ppm. More preferably, it is 3 ppm to 40 ppm. When the concentration of additive A in the sulfuric acid-based copper electrolyte is less than 1 ppm, the amount of additive A taken into the electrolytic copper foil deposited by electrolysis is insufficient, and the resulting electrolytic copper foil has a large mechanical strength. It cannot be obtained, and the change with time of the mechanical strength increases. On the other hand, if the concentration of the additive A exceeds 50 ppm, the smoothness of the deposited surface of the electrolytic copper foil is impaired, the glossiness is lowered, and it is difficult to obtain a large mechanical strength. In consideration of the fact that the additive A group includes additives having various molecular weights, it is also preferable to manage them in terms of molar concentration. In this case, it is preferable to manage the additive A in the range of 10 μmol / l to 110 μmol / l in terms of molar concentration. When the concentration of the additive A is less than 10 μmol / l in terms of molar concentration, the amount of the additive A taken into the electrolytic copper foil deposited by electrolysis is insufficient, and the obtained electrolytic copper foil cannot obtain a large mechanical strength. The change in mechanical strength with time is also increased. On the other hand, when the concentration of the additive A exceeds 110 μmol / l in terms of molar concentration, the smoothness of the deposited surface of the electrolytic copper foil is impaired, the glossiness is lowered, and it is difficult to obtain a large mechanical strength. The content of the additive A in the copper electrolyte can be confirmed using HPLC (High Performance Liquid Chromatography).

  In addition, the additive A which specified and described the specific compound name above has only illustrated what was used in the Example. Therefore, it should be clearly noted that any compound can be used as long as it has the characteristic chemical structure described above and exhibits the same effect.

  The additive B will be described. This additive B is a sulfonate salt of an active sulfur compound. This additive B acts to promote glossing of the surface of the obtained electrolytic copper foil. Specifically speaking, additive B is either 3-mercapto-1-propanesulfonic acid (hereinafter referred to as “MPS”) or bis (3-sulfopropyl) disulfide (hereinafter referred to as “SPS”). It is preferable to use a mixture. Among them, it is considered that SPS exhibits the effect as a brightener in the electrolytic solution. However, when MPS is added to the sulfuric acid copper electrolyte, this SPS may be polymerized in the solution to dimerize. Therefore, without adding SPS directly, MPS may be added to the sulfuric acid-based copper electrolyte and converted to SPS for use. Here, the structural formula of MPS is shown in Chemical formula 7, and the structural formula of SPS is shown in Chemical formula 8. From the comparison of these structural formulas, it can be understood that SPS is a dimer of MPS.

  The concentration of the additive B in the sulfuric acid copper electrolyte is preferably in the range of 1 ppm to 80 ppm, more preferably in the range of 10 ppm to 70 ppm, and still more preferably in the range of 10 ppm to 60 ppm. If the concentration is less than 1 ppm, the gloss of the deposited surface of the electrolytic copper foil is lost, and at the same time, it is difficult to stably obtain the electrolytic copper foil with high mechanical strength. On the other hand, if the concentration exceeds 80 ppm, the copper deposition state tends to be unstable, and it becomes difficult to stably obtain an electrolytic copper foil having high mechanical strength. The concentration of the additive B is a value converted to a sodium salt in order to facilitate concentration calculation.

  The additive C will be described. This additive C is a quaternary ammonium salt polymer having a cyclic structure. This additive C acts to promote the smoothing of the surface of the electrolytic copper foil produced by the electrolytic method. Specifically, it is preferable to use a diallyldimethylammonium chloride (hereinafter referred to as “DDAC”) polymer as the additive C. DDAC forms a cyclic structure when the quaternary ammonium salt takes a polymer structure, and a part of the cyclic structure is composed of a quaternary ammonium nitrogen atom. The DDAC polymer has a plurality of forms such as a 5-membered ring and a 6-membered ring structure. However, the chemical structure of the actual polymer is determined by the synthesis conditions, and it is considered that those having one or more chemical structures are mixed. Accordingly, among these polymers, compounds having a five-membered ring structure are represented here, and those having chlorine ions as counter ions are shown as chemical formula 9 below. This DDAC polymer has a polymer structure in which DDAC is a dimer or more, as shown in Chemical Formula 9 below.

  And it is preferable that the density | concentration in the sulfuric acid type copper electrolyte solution of the said additive C is the range of 0.5 ppm-100 ppm, The more preferable range is 10 ppm-80 ppm, More preferably, it is 20 ppm-70 ppm. When the concentration of additive C in the sulfuric acid-based copper electrolyte is less than 0.5 ppm, the smoothing effect of the deposited surface of the electrolytic copper foil is insufficient, and no matter how high the SPS concentration is, high mechanical strength can be obtained. As a result, the fine crystal grains necessary to obtain the low-profile surface cannot be obtained. On the other hand, even if the concentration of the additive C exceeds 100 ppm, the effect of smoothing the copper precipitation surface is not improved, but rather the precipitation state becomes unstable, and high mechanical strength can be stably obtained. It becomes difficult.

  Further, the weight concentration ratio [B concentration] / [C concentration] between the concentration of the additive B and the concentration of the additive C in the sulfuric acid-based copper electrolyte is 0.07 to 1.4. It is preferable. As described above, both additive B and additive C tend to be unstable when the concentration is high. However, the tendency of the copper deposition state to become unstable is particularly noticeable when only one component has a high concentration. Therefore, by setting the value of the weight concentration ratio [B concentration] / [C concentration] between the concentration of the additive B and the concentration of the additive C to 0.07 to 1.4, both additives are stabilized. It is effective and improves the stability of electrolytic operation. And if the value of weight concentration ratio [B density | concentration] / [C density | concentration] is 0.07-1.4, it will become easy to exhibit the effect of the chlorine addition mentioned later, and is more preferable.

  The component balance of additive A to additive C in the sulfuric acid copper electrolyte is most important. Even when an electrolytic copper foil is produced using a copper electrolyte whose quantitative balance of these additive components deviates from the above range, the electrolytic copper foil is a fine precipitate capable of obtaining high mechanical strength. No crystal grains are provided, and at the same time, a smooth and glossy precipitation surface cannot be obtained and a low profile surface cannot be obtained. Therefore, by maintaining these balances well, it is possible to stably produce an electrolytic copper foil having extremely large mechanical strength according to the present invention.

  The chlorine concentration in the sulfuric acid copper electrolyte will be described. It is important that this chlorine concentration is in the range of 40 ppm to 80 ppm. By adopting a chlorine concentration in this range, it is possible to stably produce a high-strength electrolytic copper foil containing the above-mentioned components of sulfur, carbon, and chlorine in a well-balanced manner and containing fine crystal grains. The chlorine concentration at this time is 40 pm to 80 ppm, more preferably 60 ppm to 80 ppm in a state after the additives A to C are added. When the chlorine concentration is less than 40 ppm, the obtained electrolytic copper foil cannot contain the required amounts of sulfur, carbon, and chlorine components, and the mechanical strength of the electrolytic copper foil tends to decrease. growing. On the other hand, when the chlorine concentration exceeds 80 ppm, it is difficult to obtain an electrodeposition state necessary for obtaining an electrolytic copper foil having a mechanical strength as high as that of the Corson alloy. Moreover, when it is necessary to adjust the chlorine concentration in the sulfuric acid-based copper electrolyte, it is preferable to adjust using hydrochloric acid or copper chloride. This is because the solution properties of the sulfuric acid-based copper electrolyte are not changed.

Form of the copper clad laminate according to the present invention: The copper clad laminate according to the present invention is obtained by bonding the above-mentioned surface-treated electrolytic copper foil with an insulating layer constituting material. There is no special limitation regarding the manufacturing method of the copper clad laminated board said here. However, the concept of the copper clad laminate mentioned here includes both a rigid copper clad laminate and a flexible copper clad laminate. If it is a rigid copper clad laminated board, it can be manufactured using a hot press system or a continuous laminating system. And if it is a flexible copper clad laminated board, it is possible to use the roll lamination system and the casting system which are the prior art.

  And since a rigid printed wiring board is obtained using the rigid copper clad laminate according to the present invention, and the mechanical strength of the electrolytic copper foil layer is extremely high, there are few scratches due to physical external forces, poor disconnection, etc. A fine pitch circuit will be provided. In addition, the flexible copper clad laminate is used for manufacturing a flexible printed wiring board that is required to be flexible and lightweight. The flexible copper-clad laminate using the electrolytic copper foil according to the present invention exhibits high flexibility and high printed wiring board strength because the formed conductor has extremely high mechanical strength. And since the electrolytic copper foil which concerns on this invention is a low profile, it is suitable for formation of the fine pattern circuit of the level calculated | required by a flexible printed wiring board. In particular, the bending of the flying lead when the IC chip is bonded to the flying lead in the device hole of the TAB tape, and elongation due to the bonding pressure can be eliminated.

  Hereinafter, examples are shown to facilitate understanding of the electrolytic copper foil and the manufacturing method thereof according to the present invention.

  In this example, as a sulfuric acid-based copper electrolyte, a basic solution adjusted to a copper concentration of 80 g / L and a free sulfuric acid concentration of 140 g / L was used, so that each additive concentration shown in Table 1 was obtained. It was adjusted. MPS-Na (MPS sodium salt) as additive B, DDAC polymer (Senka Co., Ltd. Unisense FPA100L) as additive C, and additive A from 2M-5S, MSPMT-C, 2MI, 2TT and EUR One of the selected ones was used, and hydrochloric acid was used to adjust the chlorine concentration. And 8 types of electrolytic copper foils of Sample 1 to Sample 8 were manufactured using sulfuric acid-based copper electrolytes having different compositions of additives shown in Table 1. The liquid compositions and electrolysis conditions of Samples 1 to 8 according to the above examples are listed in Table 1 together with the liquid compositions and electrolysis conditions of Comparative Examples.

  The electrolytic copper foil was prepared by using a titanium plate electrode whose surface was polished with # 2000 polishing paper as the cathode and DSA as the anode, and an electrolytic copper foil having a thickness of 12 μm to 18 μm was prepared. The surface roughness (Rzjis) of the glossy surface (surface opposite to the deposition surface) of these electrolytic copper foils was 0.84 μm. The evaluation results of each characteristic are summarized in Table 2 so that they can be compared with the following comparative examples and reference examples.

Here, various measurement conditions and the like will be described. The crystal grain size was measured using a scanning electron microscope, acceleration voltage: 20 kV, observation magnification: x30,000, aperture diameter: 60 mm, high current mode, tilting the observation sample to 70 °, orientation When the difference was 5 ° or more, it was regarded as a grain boundary and the crystal grain size was measured. The measurement area and step size were based on the following two conditions depending on the crystal size. The measurement of the crystal grain size after normal and heating of Sample 1 to Sample 3 and Sample 5 according to the example was set to a measurement region: 2 × 2 μm and a step size: 10 nm. Then, the measurement of the normal and post-heat crystal grain sizes of Comparative Sample B and Comparative Sample C of Comparative Examples described below were set to a measurement region: 5 × 5 μm and a step size: 30 nm. And about the measurement of tensile strength and elongation rate, it carried out based on IPC-TM-650. The surface roughness was measured according to JIS B 0601-2001. Furthermore, the glossiness was measured according to JIS Z 8741-1997. The same applies to the following comparative examples.

Comparative example

[Comparative Example 1]
In Comparative Example 1, the electrolytic solution composition was the same as that of the example except that additive A was not included. This liquid composition is shown in Table 1 later together with the liquid composition of the examples.

The electrolytic copper foil was prepared by electrolyzing a titanium plate electrode whose surface was polished with # 2000 polishing paper as the cathode and DSA as the anode at a liquid temperature of 50 ° C. and a current density of 60 A / dm ^2. An electrolytic copper foil (Comparative Sample A) having a thickness of 15 μm was prepared. The surface roughness (Rzjis) of the glossy surface of this electrolytic copper foil was 0.88 μm, the surface roughness (Rzjis) of the deposited surface was 0.44 μm, and the glossiness [Gs (60 °)] was 600 or more. It was. And the value of normal state tensile strength was 35.4 kgf / mm < ² >, and the value of normal state elongation rate was 14.3%. Furthermore, the value of the tensile strength after heating of this electrolytic copper foil was 30.7 kgf / mm ² , and the value of the elongation after heating was 14.8%. The results are shown in Table 2 below together with the results of Examples , other Comparative Examples, and Reference Examples.

[Comparative Example 2]
In Comparative Example 2, Example 2 disclosed in Patent Document 2 was traced. Specifically, a sulfuric acid-based copper sulfate aqueous solution having a sulfuric acid concentration of 100 g / L and a copper sulfate pentahydrate concentration of 280 g / L was prepared, and hydroxyethyl cellulose: 80 mg / L, polyethyleneimine: 30 mg / L, as additives. An electrolytic solution containing sodium 3-mercapto-1-propanesulfonate: 170 μmol / L, acetylene glycol: 0.7 mg / L and chloride ion: 80 mg / L was prepared.

The temperature of this electrolytic solution was set to 40 ° C., and electrolysis was performed at an electrolytic current density of 40 A / dm ² using an apparatus similar to that of the example to prepare an electrolytic copper foil (Comparative Sample B) having a thickness of 18 μm. The surface roughness (Rzjis) of the glossy surface of this electrolytic copper foil was 0.84 μm, as in the example. And the surface roughness (Rzjis) of the precipitation surface was 1.94 μm, the value of normal tensile strength was 57.7 kgf / mm ² , and the value of normal elongation was 6.8%. Moreover, the value of the tensile strength after heating of this electrolytic copper foil was 54.7 kgf / mm ² , and the value of the elongation after heating was 7.3%. The results are shown in Table 2 below together with the results of Examples , other Comparative Examples, and Reference Examples.

[Comparative Example 3]
In Comparative Example 3, Example 3 disclosed in Patent Document 2 was traced. Specifically, a sulfuric acid-based copper sulfate aqueous solution having a sulfuric acid concentration of 100 g / L and a copper sulfate pentahydrate concentration of 280 g / L was prepared. Hydroxyethyl cellulose: 6 mg / L, polyethyleneimine: 12 mg / L, An electrolytic solution containing sodium 3-mercapto-1-propanesulfonate: 60 μmol / L, acetylene glycol: 0.5 mg / L and chloride ion: 30 mg / L was prepared.

The temperature of this electrolytic solution was set to 40 ° C., and electrolysis was performed at an electrolytic current density of 40 A / dm ² using the same apparatus as in the example, to prepare an electrolytic copper foil (Comparative Sample C) having a thickness of 18 μm. The surface roughness (Rzjis) of the glossy surface of this electrolytic copper foil was 0.84 μm, as in the example. And the surface roughness (Rzjis) of the precipitation surface was 1.42 μm, the value of normal tensile strength was 57.8 kgf / mm ² , and the value of normal elongation was 6.4%. Moreover, the value of the tensile strength after heating of this electrolytic copper foil was 55.0 kgf / mm ² , and the value of the elongation after heating was 8.4%. The results are shown in Table 2 below together with the results of Examples, other Comparative Examples and Reference Examples.

[Comparative Example 4]
In Comparative Example 4, an electrolytic solution composition containing additive A in an amount outside the proper range referred to in the present invention was used. This liquid composition is shown in Table 1 later together with the liquid composition of the examples.

And as shown in Table 1, it electrolyzed by electrolytic current density 60A / dm < ² > using the conditions and apparatus similar to an Example, and produced 12-micrometer-thick electrolytic copper foil (comparative sample D). The surface roughness (Rzjis) of the glossy surface of this electrolytic copper foil was 0.84 μm, as in the example. The surface roughness (Rzjis) of the precipitation surface was 26.0 μm, the value of the normal tensile strength was 21.1 kgf / mm ² , and the value of the normal elongation was 0.4%. Moreover, the value of the tensile strength after heating of this electrolytic copper foil was 17.7 kgf / mm ² , and the value of the elongation percentage after heating was 0.2%. The results are shown in Table 2 below together with the results of Examples, other Comparative Examples, and Reference Examples.

[Comparative Example 5]
In Comparative Example 5, an electrolytic solution composition having a chlorine content less than the appropriate range in the present invention was employed. This liquid composition is shown in Table 1 later together with the liquid composition of the examples.

And as shown in Table 1, it electrolyzed by electrolytic current density 60A / dm < ² > using the conditions and apparatus similar to an Example, and produced the electrolytic copper foil (comparative sample E) of thickness 18 micrometers. The surface roughness (Rzjis) of the glossy surface of this electrolytic copper foil was 0.84 μm, as in the example. The surface roughness (Rzjis) of the precipitation surface was 20.9 μm, the value of the normal tensile strength was 44.2 kgf / mm ² , and the value of the normal elongation was 1.1%. Moreover, the value of the tensile strength after heating of this electrolytic copper foil was 42.4 kgf / mm ² , and the value of the elongation after heating was 1.1%. The results are shown in Table 2 below together with the results of Examples, other Comparative Examples, and Reference Examples.

[Reference example]
In this reference example, a Corson alloy foil having a thickness of 18 μm was used as a reference sample. The Corson alloy used for manufacturing this Corson alloy foil has a composition of Cu-2% Ni-0.5% Si-1% Zn-0.5% Sn. This Corson alloy is a precipitation hardening type alloy in which Ni ₂ Si precipitates are dispersed and precipitated in a matrix, and is known as an alloy having relatively good conductivity, strength, stress relaxation characteristics and bending workability. .

This Corson alloy foil had a normal tensile strength value of 91.5 kgf / mm ² and a normal elongation value of 5.4%. Moreover, the value of the tensile strength after heating of this electrolytic copper foil was 92.7 kgf / mm ² , and the value of the elongation after heating was 6.2%. The results are shown in Table 2 below together with the results of Examples, Comparative Examples, and Reference Examples .

<Contrast between Example and Comparative Example>
First, an example that can be understood with reference to Table 1 is compared with a comparative example. In the method for producing an electrolytic copper foil according to the present invention, when producing an electrolytic copper foil by an electrolytic method using a sulfuric acid-based copper electrolytic solution, the electrolytic solution contains the above-mentioned additive A (“heterocyclic benzene ring and N And a compound having a structure in which a mercapto group is bonded at the same time, a compound having a 5-membered ring structure in which one or more Ns are simultaneously bonded to an SH group, and a thiourea compound. 1 type), additive B (sulfonic acid salt of active sulfur compound), additive C (ammonium salt polymer having a cyclic structure), and chlorine concentration in the range of 40 ppm to 80 ppm is necessary. It is. And the value of [B density | concentration] / [C density | concentration] which is a weight concentration ratio of the density | concentration of the said additive B and the density | concentration of the said additive C in the said sulfuric acid type copper electrolyte solution is 0.07-1.4. It is preferable that

  Therefore, in the examples, a sulfuric acid-based copper electrolytic solution having a chlorine concentration in the range of 49.4 ppm to 66.0 ppm is used using the additives A to C. On the other hand, in the manufacture of the comparative sample A and comparative sample C of the comparative example, a copper electrolyte solution having a chlorine concentration of 30 ppm is used. And in manufacture of the comparative sample B of a comparative example, although the copper electrolyte solution of chlorine concentration 80ppm is used, the copper electrolyte solution used for manufacture of the comparative sample B and the comparative sample C is the electrolytic copper foil which concerns on this invention. Since acetylene glycol which is not included in the copper electrolyte used for production is included, it is impossible to apply the concept of the production method according to the present invention.

Furthermore, the value of [B concentration] / [C concentration], which is the weight concentration ratio between the concentration of the additive B and the concentration of the additive C, in the sulfuric acid-based copper electrolyte used in the present invention is 0.07 to It is preferable that it is 1.4. At this time, [B concentration] / [C concentration] = 0.40 of sample 1 of the example, [B concentration] / [C concentration] = 1.14 of sample 2, and [B concentration] / [C of sample 3]. [Concentration] = 0.67, [B concentration] / [C concentration] = 0.78 of sample 4, [B concentration] / [C concentration] = 0.21 of sample 5, [B concentration of samples 6 to 8] ] / [C concentration] = 0.86, which is in an appropriate range. On the other hand, in the manufacture of the comparative sample A of the comparative example, [B concentration] / [C concentration] = 1.33 is used, but since the additive A is not added, As will be described later, good tensile strength and good conductivity are not obtained. Further, in the production of the comparative sample D and comparative sample E of the comparative example, [B concentration] / [C concentration] = 0.85 sulfuric acid-based copper electrolyte is used, but the comparative sample D has an EUR content. The sample is out of the proper range, and the comparative sample E has a chlorine concentration less than the proper range. For this reason, as will be described later, the resulting copper foil has a low tensile strength and a rough surface such as a rough surface.

  Next, a comparison between an example and a comparative example that can be understood with reference to Table 2 is performed for each characteristic. First, a comparison regarding conductivity will be described. In the case of the reference example (Corson alloy foil obtained by the rolling method having a thickness of 18 μm), the conductivity is 48.2% IACS, which is lower than the examples and comparative examples obtained by the electrolytic method. ing. This is considered to be due to the fact that the basic bulk composition is different and the Corson alloy foil, which is a rolled foil, has a crystal structure with a large processing strain due to the formation of a texture by rolling. Therefore, in the embodiment, the conductivity is in the range of 49.3% IACS to 76.0% IACS. On the other hand, in the comparative example, it is in the range of 63.2% IACS to 87.5% IACS.

However, paying attention to the value of the tensile strength in the normal state, the tensile strength of the sample of the example is in the range of 76.8 kgf / mm ^{2 to} 94.6 kgf / mm ² . On the other hand, the tensile strength of the comparative sample of the comparative example is in the range of 21.1 kgf / mm ^{2 to} 57.8 kgf / mm ² . That is, it can be seen that the sample according to the example has an overwhelmingly higher tensile strength than the comparative sample used as the comparative example.

Even try focusing on the tensile strength after heating, the heating after the tensile strength of the samples of Examples in ^the range of ^{73.9kgf / mm 2 ~93.4kgf / mm 2} , listed in Reference Example Some exhibit the same tensile strength as Corson alloy foil. And even if it sees the change of the value with a normal state and after a heating for every sample 1-sample 8 of an Example, the big softening phenomenon is not seen. On the other hand, the tensile strength after heating of the comparative sample of the comparative example is in a low range of 17.7 kgf / mm ^{2 to} 55.0 kgf / mm ² .

  Next, when the surface roughness of the deposit surface of the electrolytic copper foil manufactured by the Example and the comparative example which were published in Table 2 is seen, the surface roughness of the comparative sample D and the comparative sample E is extremely large. From this, it can be understood that when the composition balance of the copper electrolyte is broken, a low profile precipitation surface cannot be obtained.

  Here, an example and a comparative example are contrasted regarding an average crystal particle diameter. The average crystal particle size of each sample in the normal example is in the range of 46.9 nm to 104.9 nm for the average minor axis and 149.8 nm to 381.5 nm for the average major axis. That is, it is in the range of “average minor axis length of 30 nm to 110 nm, average major axis length of 140 nm to 400 nm” which is referred to as suitable in the present invention. On the other hand, the average crystal particle size of each comparative sample in the comparative example in the normal state is in the range of 487.7 nm to 916.0 nm in average minor axis and 1217.8 nm to 2862.5 nm in average major axis, that is, the present invention. Is not included in the preferred range.

  Further, the average crystal particle diameter of each sample of the example after heating is in the range of 33.0 nm to 117.0 nm in average minor axis and 113.7 nm to 468.0 nm in average major axis. That is, it is in the range of “average minor axis length of 25 nm to 120 nm, average major axis length of 100 nm to 500 nm” which is referred to as suitable in the present invention. On the other hand, the average crystal particle diameter of each comparative sample of the comparative example after heating is in the range of the average minor axis from 432.7 nm to 974.0 nm and the average major axis from 2617.5 nm to 2872.7 nm. In the invention, the crystal grain size after heating is not included in the preferred range.

  Moreover, in the present invention, the average major axis length and the average minor axis length of the normal crystal particles have a relationship of [average minor axis length] / [average major axis length] = 0.1 to 0.5. Is required to have At this time, in the sample of an Example, it is in the range of [length of average minor axis] / [length of average major axis] = 0.16 to 0.45.

Regarding the average crystal particle size described above, it can be understood that the average crystal particle size of the example is much smaller both in the normal state and after heating than in the comparative example. It can be said that the electrolytic copper foil of the example exhibits high tensile strength due to the fineness of the crystal particle diameter. On the other hand, compared with the comparative example, the crystal particle diameter of the example is fine, and the density of the crystal grain boundary in the crystal structure is increased, so that the electrical resistance is considered to be increased. As a result, it is considered that the conductivity of the example is lower than the conductivity of the comparative example.

  Next, the elongation rate will be described. As is clear from Table 2, it is specified that, except for the comparative sample A, it is an elongation rate generally found as an electrolytic copper foil, and is not a value that limits its use in the field of electronic materials. Keep it.

  Furthermore, the surface roughness will be described. The electrolytic copper foil according to the present invention and the electrolytic copper foil used as a comparative example are all manufactured as a low profile copper foil. Therefore, it cannot be said that there is a large difference with respect to the Rzjis value measured by the surface roughness meter.

  When attention is paid to the glossiness, the glossiness of the electrolytic copper foil obtained in the example according to the present invention is 118 to 636 in MD (flow direction) glossiness and 102 in TD (width direction) glossiness. The range of ˜586 is shown, and it can be said that the glossiness is sufficiently good.

Finally, Table 3 will be described. As described above, the electrolytic copper foil according to the present invention preferably contains 110 ppm to 400 ppm of sulfur, 250 ppm to 470 ppm of carbon, 280 ppm to 650 ppm of chlorine, and 40 ppm to 180 ppm of nitrogen. As can be seen from Table 3, the component amounts of sulfur, carbon, chlorine, and nitrogen of each sample of the examples are within this range. However, it is clear that any component amount of sulfur, carbon, chlorine, and nitrogen in each comparative sample of the comparative example is out of the proper range described above. And in the case of the electrolytic copper foil which concerns on this invention, it can be said that it is a remarkable characteristic that especially the amount of sulfur and nitrogen is high, and this seems to satisfy said each mechanical characteristic comprehensively.

  In view of the above, from the viewpoint of supplying electrolytic copper foil with mechanical strength equivalent to that of Corson alloy foil to the market, the electrolytic copper foil described as an example according to the present invention is Corson, which is a reference example. It is clear that it has mechanical strength equivalent to that of alloy foil, and also has conductive performance exceeding that of Corson alloy foil, and that it can satisfy all the basic characteristics required for electrolytic copper foil for other electronic materials. is there.

  Since the electrolytic copper foil according to the present invention is composed of the deposited crystal particles of the nm order as described above, it can be provided with extremely large mechanical strength equivalent to that of the Corson alloy foil due to the effect of refining the crystal grains. . Moreover, the mechanical strength of the electrolytic copper foil according to the present invention is almost the same as the normal mechanical strength even after heating at 180 ° C. for 60 minutes. And since the particle diameter of the crystal | crystallization is fine, the low profile precipitation surface of the same level as the conventional low profile electrolytic copper foil is provided. And, using the electrolytic copper foil according to the present invention, surface treatment for the purpose of rust prevention treatment, roughening treatment for improving adhesion with the base resin, silane coupling agent treatment, etc. By applying, a surface-treated copper foil having good mechanical strength and a low profile surface can be obtained. Such a surface-treated copper foil is suitable as a constituent material for a high-quality printed wiring board material having a fine pitch circuit, a negative electrode current collector for a lithium secondary battery that requires high durability performance, and the like.

  Moreover, even if the copper clad laminated board obtained using the said surface-treated electrolytic copper foil is thin, due to the extremely large mechanical strength of the electrolytic copper foil, there is little deflection and deformation during handling, and it becomes easy to handle. In particular, if the electrolytic copper foil is laminated with a film that is an insulating layer forming material to form a flexible copper clad laminate, and this is used for a TAB substrate application that requires a fine pitch, it cannot be put into practical use by conventional techniques. Fine flying leads can be formed.

  Furthermore, the method for producing an electrolytic copper foil according to the present invention is characterized by the composition of the copper electrolyte used. This copper electrolyte is excellent in solution stability and withstands long-term continuous use, so that it is economically superior. Furthermore, the manufacturing equipment to be used does not require a new capital investment, and the conventional electrolytic copper foil manufacturing equipment can be used, which does not increase the manufacturing cost.

Claims (15)

In the electrolytic copper foil obtained by electrolyzing the copper electrolyte,
The electrolytic copper foil contains 110 ppm to 400 ppm of sulfur, 280 ppm to 650 ppm of chlorine,
An electrolytic copper foil having an electrical conductivity of 49.3% IACS or more and a tensile strength value of 70 kgf / mm ² or more in a normal state. The electrolytic copper foil according to claim 1, wherein the electrolytic copper foil contains 250 ppm to 470 ppm of carbon. The electrolytic copper foil according to claim 1 or 2, wherein the electrolytic copper foil contains 40 ppm to 180 ppm of nitrogen. The electrolytic copper foil in a normal state includes crystal grains grown from the precipitation start surface toward the precipitation end surface, and the average minor axis length of the crystal grains is 30 nm to 110 nm, and the average major axis length is 140 nm to 400 nm. The electrolytic copper foil as described in any one of Claims 1-3 provided with the precipitation structure | tissue comprised by the crystal grain. The electrolytic copper foil after heating at 180 ° C. for 60 minutes includes crystal grains grown from the precipitation start surface toward the precipitation end surface, and the average minor axis length of the crystal grains is 25 nm to 120 nm. The electrolytic copper foil as described in any one of Claims 1-4 provided with the precipitation structure | tissue comprised by the crystal grain whose length is 100 nm-500 nm. The relationship between the average major axis length and the average minor axis length of the normal crystal grains in the cross section near the precipitation surface is [average minor axis length] / [average major axis length] = 0.1 to 0.5. The electrolytic copper foil as described in any one of Claims 1-5 provided with these. The electrolytic copper foil according to any one of claims 1 to 6 , wherein a value of tensile strength after heating at 180 ° C for 60 minutes is 85% or more of a value of normal tensile strength. The value of the gloss was measured with respect to the width direction of the deposition surface [Gs (60 °)] is, electrolytic copper foil according to any one of claims 1 to 7 100 or more. The surface of the electrolytic copper foil according to any one of claims 1 to 8 is subjected to any one or more of roughening treatment, rust prevention treatment, and silane coupling agent treatment. Surface treated electrolytic copper foil. It is the method of manufacturing the electrolytic copper foil as described in any one of Claims 1-8 by the electrolytic method using a sulfuric acid system copper electrolyte solution,
The sulfuric acid-based copper electrolytic solution includes the following additive A to additive C and has a chlorine concentration of 40 ppm to 80 ppm.
Additive A: Compound having a structure in which a heterocyclic ring contains a benzene ring and N and simultaneously having a mercapto group bonded thereto, Compound having a 5-membered ring structure in which one or more N atoms are bonded to a heterocyclic ring and SH group is simultaneously bonded One or more compounds selected from thiourea compounds.
Additive B: sulfonate salt of active sulfur compound.
Additive C: ammonium salt polymer having a cyclic structure. The compound having a structure in which the heterocyclic ring as the additive A contains a benzene ring and N and a mercapto group is bonded at the same time,
The production of an electrolytic copper foil according to claim 10 , wherein any one of 2-mercapto-5-benzimidazolesulfonic acid, 3 (5-mercapto-1H-tetrazolyl) benzenesulfonate, and 2-mercaptobenzothiazole is used. Method. The compound having a five-membered ring structure containing one or more N in the heterocyclic ring as the additive A and simultaneously having an SH group bonded thereto,
The method for producing an electrolytic copper foil according to claim 10 or 11 , wherein either 2-mercapto-imidazole or 2-thiazoline-2-thiol is used. The method for producing an electrolytic copper foil according to any one of claims 10 to 12 , wherein the thiourea compound as the additive A is diethyl thiourea. The value of [B concentration] / [C concentration], which is a weight concentration ratio between the concentration of the additive B and the concentration of the additive C, in the sulfuric acid-based copper electrolyte is 0.07 to 1.4. The manufacturing method of the electrolytic copper foil as described in any one of Claims 10-13 . A copper clad laminate obtained by laminating the surface-treated electrolytic copper foil according to claim 9 with an insulating layer constituting material.