JP2011174146A - Electrolytic copper foil and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic copper foil having a low roughness surface which is suitable for an electrolytic copper foil material used for a Tape Automated Bonding method and does not substantially have an uneven shape formed in a rough surface side, has high tensile strength, and does not cause the peeling of a tin plating film. <P>SOLUTION: This method for producing the electrolytic copper foil includes: using an aqueous solution of sulfuric acid and copper sulfate as an electrolytic solution; using an insoluble anode made from a platinum group element or titanium covered with an oxide of the platinum group element, and a cathode drum made from titanium opposing to the anode; and passing a direct current between both of the electrodes, wherein the electrolytic solution contains a non-ionic water-soluble polymer, a sulfonate of an active organosulfur compound, a thiourea-based compound and a chlorine ion existing therein. Thereby obtained electrolytic copper foil has: a rough surface of which the roughness is 2.0 μm or less; a crystal structure on the rough surface side, in which the orientation index determined from a relative intensity in a 220 copper diffraction line measured with an X-ray diffraction technique is 5.0 or more; and tensile strength of 500 MPa or more after having been heated at 180°C for 1 hour. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electrolytic copper foil, in particular, an electrolytic copper foil suitable for an electronic circuit board material and a method for producing the same.

  As is well known, the electrolytic copper foil is manufactured by the following method using a plating technique.

  That is, an aqueous solution composed of sulfuric acid and copper sulfate is used as an electrolytic solution, and the electrolytic solution is filled between a cylindrical titanium drum as a cathode and an insoluble anode as an anode, and a direct current is passed between both electrodes, whereby the cathode surface Copper precipitates on the surface. At this time, the cathode drum is rotating at a constant speed, and the deposited electrolytic copper is peeled off from the drum surface and continuously taken up. In addition, among those skilled in the art, the surface that was in contact with the drum of the peeled copper foil is referred to as the “glossy surface”, and the opposite surface is referred to as the “rough surface”, and the electrolytic copper foil is referred to as “ It is called “untreated electrolytic copper foil”.

  Usually, when untreated electrolytic copper foil is used for electronic circuit board applications, various surface treatments are applied to improve adhesion to the resin and to provide chemical resistance and rust prevention. Those skilled in the art have referred to the “treated electrolytic copper foil” after the various surface treatment steps.

  In recent years, electronic circuit boards, which are the main applications of electrolytic copper foil, have caused various problems associated with downsizing, high integration, and higher frequency of electronic devices typified by mobile communication devices.

  Electronic circuit boards are broadly divided into inflexible rigid wiring boards and flexible flexible wiring boards from the viewpoint of flexibility of the base material that is an insulating material, and rigid flexible wiring that combines these two. If the substrate is included, it is roughly classified into three.

  The TAB (Tape Automated Bonding) method, which belongs to the flexible wiring board construction method, is a method for manufacturing an electronic circuit board in which IC chips are continuously automatically connected to a tape-like film wired with copper, and the IC chips are directly taped. Because it is mounted on "TAB tape" like a photographic film made of polyimide, high-speed electronic circuit boards can be produced at high speed.

  The feature of the TAB method is that an IC chip is mounted on the part where the film called “device hole” is punched, and the copper wiring called fine “flying lead” formed by etching around this device hole. Is exposed and the IC chip is connected to this flying lead.

  Recently, since the circuit width of this flying lead part has been miniaturized to 20μm, the flying lead part is deformed by the bonding process when mounting the IC chip and the etching spray pressure when forming the circuit, which increases the defect rate. The problem of letting go.

As means for solving the above-mentioned problem, Patent Document 1 described below discloses that the rough surface roughness of copper foil is Rz of 2.5 μm or less, and the tensile strength after oven heating at 180 ° C. for 1 hour is 40 kgf / mm ² (392 MPa). X-rays of the peaks of the (111), (200), (220), and (311) planes of the copper crystal on the rough surface of the electrolytic copper foil measured by X-ray diffraction. It is disclosed that a high tensile strength copper foil oriented in a disorderly manner with respect to strength is effective (the crystal surface notation method follows the notation of the corresponding patent publication).

Further, in Patent Document 2 described later, an electrolytic copper foil in which copper precipitation particles are fine and variation in the particle diameter is made smaller than before, and the electrolytic copper foil has a low profile and a glossy surface. It has a normal tensile strength value of 70-100 kgf / mm ² (686-980 MPa) and a normal tensile strength value even after heating (180 ° C. × 60 minutes). Therefore, it is disclosed that it is effective as an electrolytic copper foil for TAB.

  Further, in Patent Document 3 mentioned later, the rough surface roughness Rz of the electrolytic copper foil is 2.5 μm or less, the tensile strength measured within 20 minutes from the completion of electrodeposition is 820 MPa or more, and the copper foil The low-roughened surface electrolytic copper foil whose tensile strength measured at 25 ° C is 10% or less with respect to the copper foil whose tensile strength measured after heat treatment at 100 ° C for 10 minutes from the completion of electrodeposition is 25% It is disclosed that it is effective as an electrolytic copper foil for TAB.

  Thus, among those skilled in the art, electrolytic copper foil with excellent thermal stability that can maintain high tensile strength even after heating, assuming a heat history when laminating with a polyimide film, is used for TAB. It is known to be effective as an electrolytic copper foil.

  Therefore, it can be said that it is an effective measure to improve the tensile strength of the electrolytic copper foil for the flying lead portion which is being made fine wiring in the TAB method.

  In Patent Document 4 mentioned later, thiourea is added to an electrolytic solution, and an organic substance such as polyethylene glycol is added, and the chlorine ion concentration in the electrolytic solution is kept below 1 ppm, so that the tensile strength is high and its thermal stability. The manufacturing method which obtains the electrolytic copper foil which is excellent in is disclosed.

  Furthermore, as an electrolytic copper foil for TAB, in addition to high tensile strength, the quality of tin plating is questioned.

  In other words, tin plating is usually applied to the electrolytic copper foil for TAB as a surface treatment for solderability protection, but the plating surface called “nodule” or “whisker” is used for tin plating on copper. There are peculiar anomaly problems such as anomalies and Kirkendall voids caused by the rapid diffusion of copper atoms into the tin layer at the copper-tin interface. Such an abnormality of the tin plating surface is a cause of an accident that causes problems such as a short circuit between the fine wiring circuits and peeling of the plating surface.

  However, those skilled in the art have overcome this problem by using Sn—Pb alloy plating instead of tin alone as a countermeasure against the problem of tin plating surface abnormality.

  However, in recent years, the use of Sn-Pb alloy plating containing lead has been refrained from the viewpoint of prevention of lead release to the environment, and tin-only electroless plating has been applied, resulting in Sn-Pb alloy plating. At present, abnormal problems such as whiskers and Kirkendall voids that have calmed down have come to be noticed again.

  Therefore, the electrolytic copper foil for TAB has the following advantages: (1) High tensile strength, and (2) Thin line in order to meet the fine line and fine patterning required in common with recent electronic circuit boards. From the viewpoint of ensuring the reliability of the foil and the rough surface is a low rough surface, (3) it is required that the tin plating surface abnormality is not likely to occur.

  However, according to the knowledge of the present inventors, an electrolytic copper foil having a fine crystal structure and a random orientation orientation of the crystal structure has a high tensile strength and a low rough surface. Although the requirements of (1) and (2) are satisfied, it has been clarified that tin plating is easily peeled off. This tin plating peeling phenomenon does not occur when the tensile strength is low even with random orientation. Although the details of this phenomenon are not clear, the present inventors presume that the size of the copper crystal grains is involved.

  When the present inventors examined each of the electrolytic copper foils described in the preceding references 1-4, the crystal structure showed random orientation and high tensile strength, and tin plating was directly applied to these electrolytic copper foils. When applied, the tin plating layer was easily peeled off.

  In addition, it is considered that those skilled in the art avoid the tin plating peeling by applying nickel plating of the internal diffusion barrier as a countermeasure.

  However, it is not preferable to apply nickel plating to the internal diffusion barrier because it increases the number of processes from the viewpoint of electrolytic copper foil production, and at the time of forming the flying lead portion, both surfaces of the surface-treated electrolytic copper foil are pretreated with tin plating. Since the copper foil cross section without the nickel barrier layer is exposed on the circuit side part formed by etching, even if a nickel layer is provided, it effectively functions as an internal diffusion barrier for the tin plating layer I can say no.

The present inventors have a crystal structure in which a rough surface, which is a well-known general electrolytic copper foil, is {110} plane-oriented, not an electrolytic copper foil having fine crystal particles having random orientation orientation. In the case of electrolytic copper foil, paying attention to the fact that tin plating peeling does not occur even if it exhibits a high tensile strength of 40 kgf / mm ² (392 MPa) or more, it has a stronger {110} oriented crystal structure, Realizing high tensile strength and low rough surface is considered to be optimal for electrolytic copper foil for TAB.

In addition, among those skilled in the art, an electrolytic copper foil having a crystal structure exhibiting {110} plane orientation is known as a very general electrolytic copper foil, and a mountain-valley shape is formed on the rough surface side thereof. It is a general recognition that the roughness of the rough surface side is rough. For example, in Non-Patent Document 1 described later, when both chlorine ions and gelatin are added to a sulfuric acid-copper sulfate aqueous solution, chloride ions are selected. Adsorbs to the (220) plane and promotes the growth of the surface, while gelatin selectively adsorbs to the (111) plane and suppresses the creeping growth of precipitates, thereby forming an acute pyramid-like form. is a is obtained, the rear left non-patent document 2, sulfate - gelatin and Cl in aqueous solution of copper sulfate ^- an electrolyte copper foil plus is {110} orientation, Rz values are largely surface roughness greater ing.

Japanese Patent No. 3346774 JP 2008-101267 A Japanese Patent No. 4273309 JP-A-7-188969

Nobuyuki Koura et al. Surface Technology 51,938 (2000) Kazuo Kondo et al. Journal of Japan Institute of Electronics Packaging 6,64 (2003)

  In view of the above circumstances, the present invention is an electrolytic copper foil having a crystal structure exhibiting {110} plane crystal orientation in which tin plating peeling does not occur, and is low in which a valley shape is not substantially formed on the rough surface side. An object of the present invention is to provide an electrolytic copper foil having a rough surface (a smooth rough surface having gloss) and a high tensile strength.

  As a result of many trial manufactures and experiments in order to solve the above problems, the present inventor has found that a nonionic water-soluble polymer, a sulfonate of an active organic sulfur compound, When urea-based compounds and chlorine ions coexist, the surface roughness is a low-roughness surface with a roughness of 2.0 μm or less, and is determined from the relative intensity of the diffraction diagram observed by X-ray diffraction on the rough surface side {110 } We have obtained a remarkable finding that an electrolytic copper foil having a crystal structure with a surface orientation index of 5.0 or higher and a high tensile strength of 500 MPa or higher at 180 ° C. for 1 hour can be obtained. Achieved.

  The technical problem can be solved by the present invention as follows.

  That is, the electrolytic copper foil according to the present invention is a crystal having a rough surface roughness Rz of 2.0 μm or less and an orientation index of 5.0 or more determined from the relative intensity of 220 copper diffraction lines measured by X-ray diffraction on the rough surface side. It is characterized by being an organization.

  The electrolytic copper foil according to the present invention is characterized in that the tensile strength after heating at 180 ° C. for 1 hour is 500 MPa or more.

  Furthermore, the method for producing an electrolytic copper foil according to the present invention comprises an insoluble anode made of titanium coated with a platinum group element or an oxide thereof using a sulfuric acid-copper sulfate aqueous solution as an electrolytic solution, and a titanium cathode drum facing the anode. In the method for producing an electrolytic copper foil in which a direct current is passed between the electrodes, a nonionic water-soluble polymer, a sulfonate of an active organic sulfur compound, a thiourea compound, and a chloride ion are present in the electrolyte. Thus, a crystal structure having a rough surface roughness of 2.0 μm or less and an orientation index of 5.0 or more determined from the relative intensity of 220 copper diffraction lines measured by X-ray diffraction on the rough surface side, which is 180 ° C. · 1 It is characterized in that an electrolytic copper foil having a tensile strength after heating for 500 hours or more is obtained.

  According to the present invention, a rough surface roughness is obtained by allowing a nonionic water-soluble polymer, a sulfonate of an active organic sulfur compound, a thiourea compound, and a chloride ion to coexist in an electrolytic solution composed of a sulfuric acid-copper sulfate aqueous solution. Is a crystal structure whose orientation index of copper 220 diffraction line relative intensity measured by X-ray diffraction on the rough surface side is 5.0 or more, and the tensile strength after heating at 180 ° C for 1 hour is 500 MPa or more It is possible to produce an electrolytic copper foil (untreated copper foil) that does not cause peeling of tin plating, and the electrolytic copper foil is suitable as a surface-treated copper foil material for TAB.

  Therefore, it can be said that the industrial applicability of the present invention is very high.

It is an X-ray diffraction pattern when the electrolytic copper foil obtained in Example 1 is scanned from the mat surface at a scanning angle of 2θ = 40 to 100 °. It is an X-ray diffraction pattern when the electrolytic copper foil obtained in Comparative Example 1 is scanned from the mat surface at a scanning angle: 2θ = 40 to 100 °.

  Embodiments of the present invention will be described below.

  First, in this invention, the additive added to the electrolyte solution which consists of sulfuric acid-copper sulfate aqueous solution is a nonionic water-soluble polymer, the sulfonate of an active organic sulfur compound, a thiourea type compound, and a chloride ion. Among these, the combination of the nonionic organic compound and the thiourea compound plays an important role, and in particular, the presence of the thiourea compound in the electrolyte is important. Needless to say, it also has a great influence on the crystal orientation that is most important to the inventors.

  As the nonionic water-soluble polymer compound in the present invention, polyglycerin, acetylene glycol, hydroxyethyl cellulose and the like can be selected. These nonionic water-soluble polymers are preferably added to the electrolytic solution in the range of 5 to 40 mg / L, more preferably in the range of 10 to 20 mg / L. If the concentration is less than 5 mg / L, the rough surface side does not become low-roughness (glossy) even if the sulfonate of the active organic sulfur compound is added. Even if an amount exceeding 40 mg / L is added, the physical properties and the appearance on the rough surface side do not change, and it is uneconomical to maintain such a high concentration. These nonionic water-soluble polymer compounds can be used alone or in combination of two or more, as long as they are within the above-mentioned concentration range.

  Examples of the active organic sulfur compound in the present invention include sodium 3-mercapto-1-propanesulfonate and sodium bis (3-sulfopropyl) disulfide, and the active organic sulfur compound may be added to the electrolytic solution in the range of 2.0 to 40 mg / L. Preferably, it is in the range of 5 to 10 mg / L. If this concentration is less than 2.0 mg / L, sufficient low roughness (glossing) will not occur, and if it exceeds 120 mg / L, the rough surface side that has been reduced (glossed) in the optimum concentration range will lose gloss. The roughness increases.

  Examples of the thiourea compound in the present invention include thiourea, ethylene thiourea, N, N′-diethylthiourea, N, N′-dibutylthiourea, trimethylthiourea and the like, and these may be used alone or in combination of two or more. Add to electrolyte. These compounds are preferably added to the electrolytic solution in the range of 0.5 to 7.0 mg / L, more preferably in the range of 1.0 to 3.0 mg / L. When the amount added is less than 0.5 mg / L, an improvement in low roughness (gloss) is observed, but the tensile strength measured after 1 hour at 180 ° C is less than 450 MPa and the copper 110 diffraction line observed from the rough surface side. The orientation index calculated from the strength is less than 5.0 and exhibits random orientation. When the added amount exceeds 7.0 mg / L, the orientation index is again less than 5.0, and random orientation is exhibited, resulting in an increase in mat surface roughness and a decrease in gloss. When the addition amount of the thiourea compound is further increased, powdery precipitation occurs on the rough surface of the copper foil, resulting in a so-called “burnt” state in plating.

  The presence of chloride ions in the present invention is important, and the presence of chloride ions is essential for all of the additives to function effectively in the preferred concentration ranges. The chloride ion concentration in the electrolytic solution is preferably controlled in the range of 20 mg / L to 70 mg / L, more preferably 40 to 60 mg / L. If it is less than 20 mg / L, the crystal orientation becomes random, and the tensile strength after heating at 180 ° C. for 1 hour cannot be maintained at 450 MPa or more and softens. When the chlorine ion concentration exceeds 70 mg / L, the roughness of the rough surface tends to be rough, and in order to control this, it is necessary to increase the concentration of the sulfonate or thiourea compound of the active organic sulfur compound. It is uneconomical.

  Note that hydrochloric acid may be used as the chlorine ion source.

Next, in the present invention, the nonionic water-soluble polymer, the sulfonate of the active organic sulfur compound, the thiourea compound, and the chloride ion are added to the respective preferable ranges in the electrolytic solution composed of sulfuric acid-copper sulfate aqueous solution. Adjusted and added, this electrolyte solution is supplied between an insoluble anode coated with a platinum group oxide and a cathode cathode made of titanium as a cathode, an electrolyte temperature of 35 to 60 ° C., an electrolytic current density of 20 to 80 A / The target electrolytic copper foil can be obtained by direct current electrolysis under the dm ² electrolysis conditions.

  In addition, the electrolytic copper foil according to the present invention is not only used for TAB, but also can be used widely as a material for printed wiring boards having high tensile strength if a treated electrolytic copper foil is subjected to a surface treatment such as a known roughening treatment. it can.

  Example 1

A sulfuric acid-copper sulfate aqueous solution consisting of sulfuric acid (H ₂ SO ₄ ): 100 g / L and copper sulfate pentahydrate (CuSO ₄ · 5H ₂ O): 280 g / L was prepared (hereinafter, this electrolyte was referred to as “basic electrolysis”). "Liquid").

  As additives, polyglycerin (trade name: polyglycerin, product number: PGL-X, manufactured by Daicel Chemical Industries, Ltd.), sodium 3-mercapto-1-propanesulfonate, N, N-diethylthiourea (trade name: Sunseller EUR) Sanshin Chemical Co., Ltd.) and hydrochloric acid are added to the basic electrolyte, and the concentration relative to the basic electrolyte is polyglycerol: 30 mg / L, sodium 3-mercapto-1-propanesulfonate: 5 mg / L, N, N-diethylthio Urea: 1.5 mg / L, chloride ion: 35 mg / L (see Table 1 below).

An electrolytic solution containing each of the above additives is supplied between an insoluble anode made of titanium coated with a platinum group oxide and a titanium cathode drum as a cathode. Electrolytic current density: 40 A / dm ² , electrolyte temperature: Electrolysis was performed at 40 ° C. to obtain an untreated electrolytic copper foil having a thickness of 18 μm.

  The following evaluation tests were performed on the obtained electrolytic copper foil (untreated copper foil).

  (1) Mechanical property evaluation

  Tensile strength (MPa) and elongation (%) are evaluated based on IPC-TM-650 using an IM20 type tensile tester manufactured by Intesco. In addition, in order to evaluate the thermal stability of the tensile strength, a tensile test measurement of an evaluation copper foil heat-heated in an air oven at 180 ° C. for 1 hour is performed.

  (2) Surface roughness evaluation test

  The surface roughness of the rough surface is measured using a surf coder SE-1700α manufactured by Kosaka Laboratory, and the ten-point average roughness, Rz, defined in JIS B0601-1994.

(3) Tin plating property evaluation test The obtained untreated electrolytic copper foil is subjected to electroless tin plating according to a conventional method, and peeling of the plating layer is evaluated by the following test method.

  First, an evaluation copper foil is cut out to 20 mm × 50 mm to obtain a test piece, which is subjected to heat treatment at 180 ° C. for 1 hour. Next, a soft etching aqueous solution adjusted to sulfuric acid, 100 mL / L, hydrogen peroxide solution and 25 mL / L is prepared, and the test piece is immersed in this aqueous solution kept at 25 ° C. for 1 minute. Immediately after the immersion for 1 minute, it is pulled up from the aqueous solution and washed with ion-exchanged water. Next, it is immersed in an aqueous solution of 55 mL / L sulfuric acid at 25 ° C. for 1 minute, pulled up from the aqueous solution and washed again with ion-exchanged water. Next, the test piece was immersed in TINPOSIT LT-34 (trade name) electroless tin plating solution made by Rohm and Haas for 3 minutes after maintaining the liquid temperature at 65 ° C. After a predetermined plating time had elapsed, the test piece was electroless Pull up from the tin plating solution, rinse with ion-exchanged water, and air dry. The tin-plated test piece thus prepared is heat-treated in an air oven set at 150 ° C. for 240 minutes and then taken out to room temperature.

  Next, the adhesion of the tin plating layer is evaluated by a cellophane adhesive tape test.

  The cellophane adhesive tape test uses a 12 mm wide cellophane adhesive tape (Sekisui, No. 252) specified in JIS Z 1522. This cellophane adhesive tape is air over the tin plating surface of the tin plating test piece over a length of 20 mm. Paste it so that it does not enter, and leave one end floating above the plating surface without sticking. The cellophane adhesive tape is left for 1-2 minutes after being applied.

  The opposite surface of the tin-plated test piece (the surface on which the cellophane adhesive tape is not affixed) is fixed to a 3 mm thick aluminum plate using a double-sided adhesive tape. Next, one end of the cellophane adhesive tape floating above the plated surface is held at an angle of 90 ° with respect to the plated surface and peeled off within 1 second. At this time, tin plating property is evaluated by the presence or absence of the peeling tin plating layer to the cellophane adhesive tape side.

(4) Crystal plane orientation evaluation test Crystal orientation is calculated based on the method of Willson. Willson's method is based on the relative intensity of diffraction lines of copper powder that does not have a specific orientation. On the other hand, the specific orientation plane is expressed as an index from the relative intensity of diffraction lines from each crystal plane of the electrolytic copper foil that is the object of evaluation It is.

  Here, the numerical value described in ASTM card 4-0836 is adopted as the relative intensity of the X-ray diffraction line of the non-oriented copper serving as a reference.

  On the other hand, the evaluation of the electrolytic copper foil measures the X-ray diffraction line intensity from the rough surface side. Diffraction line measurement is performed using RINT2000 RINT2000. The measurement conditions are a copper target X-ray tube, tube voltage 40 kV, tube current 30 mA, scanning angle 2θ, 40 ° to 100 °, and scanning speed 4 ° / min.

  The relative intensity of the five copper diffraction lines observed in the scanning range of the scanning angle 2θ, that is, the diffraction lines 111, 200, 220, 311 and 222, and the relative strength of the non-oriented copper described in the ASTM card 4-0836. The orientation index is calculated by the method of Willson using the intensity.

  A specific calculation method is as follows, taking the copper 111 diffraction line as an example.

IF ₁₁₁ is a value obtained by dividing the relative intensity I ₁₁₁ of the 111 diffraction line on the rough surface side of the electrolytic copper foil by the total relative intensity of the ₁₁₁ , 200, 220, 311 and 222 diffraction lines. That is,
IF ₁₁₁ = I ₁₁₁ / (I ₁₁₁ + I ₂₀₀ + I ₂₂₀ + I ₃₁₁ + I ₂₂₂ )
It becomes.

Next, similarly, IFR ₁₁₁ is obtained from the relative strength of ASTM card 4-0836 which is non-oriented copper. That is,
IFR ₁₁₁ = IR ₁₁₁ / (IR ₁₁₁ + IR ₂₀₀ + IR ₂₂₀ + IR ₃₁₁ + IR ₂₂₂ )
The orientation index of 111 diffraction lines is
Orientation index ₁₁₁ = IF ₁₁₁ / IFR ₁₁₁
It becomes.

  For the other diffraction lines, the same operation is performed to the electrodeposition drum surface, which is the substrate surface, among the five crystal planes that cause the X-ray diffraction phenomenon at a scanning angle of 2θ = 40 ° to 100 °. The crystal plane that is most strongly oriented can be expressed by an orientation index index.

  As is clear from the calculation method, the orientation index calculated from each diffraction line is 1 if all crystal planes are non-oriented, and if a specific crystal plane is strongly oriented, The orientation index obtained from the diffraction line generated by the diffraction is a value larger than 1.

  The results of the evaluation tests (1) to (4) are shown in Table 2 and Table 3 below.

  Examples 2-5, Comparative Examples 1-4

  An electrolytic copper foil having a thickness of 18 μm was obtained under the same conditions as in Example 1 except that the type of additive, the concentration relative to the basic electrolyte, the electrolytic current density, and the electrolyte temperature were changed as shown in Table 1 below. It was. And each evaluation test same as Example 1 was done about the obtained untreated electrolytic copper foil. The results are shown in Table 2 and Table 3 below.

  FIG. 1 shows an X-ray diffraction pattern on the rough surface side of the untreated electrolytic copper foil obtained in Example 1, and FIG. 2 shows an X-ray diffraction pattern on the rough surface side of the untreated electrolytic copper foil obtained in Comparative Example 1. The figure is shown.

  In FIG. 1, the intensity of 220 diffraction lines is strongly observed, which indicates that the copper foil has a crystal structure with a strong {110} plane orientation. On the other hand, in FIG. 2, 111 and 200 diffraction lines are observed stronger than 220 diffraction lines, and it can be seen that there is no strongly oriented crystal plane.

Claims (3)

An electrolytic copper foil characterized by having a rough surface roughness Rz of 2.0 μm or less and a crystal structure having an orientation index of 5.0 or more determined from a relative intensity of 220 copper diffraction lines measured by X-ray diffraction on the rough surface side . The electrolytic copper foil according to claim 1, wherein the tensile strength after heating at 180 ° C for 1 hour is 500 MPa or more. An electrolytic copper foil in which a sulfuric acid-copper sulfate aqueous solution is used as an electrolytic solution, and an insoluble anode made of titanium coated with a platinum group element or an oxide thereof and a titanium cathode drum facing the anode are used to pass a direct current between the two electrodes In the production method of the present invention, a non-ionic water-soluble polymer, a sulfonate salt of an active organic sulfur compound, a thiourea compound, and a chlorine ion are present in the electrolytic solution, so that a rough surface roughness is 2.0 μm or less. An electrolytic copper foil having a crystal structure with an orientation index of 5.0 or more determined from the relative intensity of 220 copper diffraction lines measured by X-ray diffraction on the rough surface side and having a tensile strength of 500 MPa after heating at 180 ° C. for 1 hour is obtained. The manufacturing method of the electrolytic copper foil characterized by the above-mentioned.

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