Copper film

Abstract

The purpose of the present invention is to provide a novel copper film. Disclosed is a copper film which is formed on a metal lead frame, and is composed of a particle assembly film that has a specific surface area of 1.3 × 10-3m2 / g to 2.2 × 10-3m2 / g, wherein particle assemblies that form the particle assembly film have a size of 15 µm or less.

Description

Copper coating

[0001] The present invention relates to copper coatings.

[0002] In semiconductor devices, semiconductor elements are mounted on lead frames, and the semiconductor elements and lead frames are electrically connected by bonding wires. The mounted semiconductor elements and lead frames are then fixed in place with molding resin. In recent years, there has been a demand for suppressing heat generated by high-efficiency semiconductor elements and for improving the adhesion of molding resins to accommodate the miniaturization of semiconductor device components.

[0003] A method has been reported for bonding a semiconductor element to a lead frame, in which a film with a high arithmetic mean height (Sa) is formed on the lead frame itself and on its surface to improve adhesion between the lead frame and molding resin.

[0004] For example, Patent Document 1 discloses a lead frame in which a noble metal plating layer is formed on the surface of a base metal via an undercoat plating layer, in which the undercoat plating layer is formed by plating a smooth Ni plating layer on the base metal using a DC current or pulse current without a polarity reversal component, and then plating a roughened Ni plating layer on the smooth Ni plating layer using a current including a polarity reversal pulse. This technology requires selective formation of the smooth Ni plating layer and the roughened Ni plating layer on the lead frame to ensure smooth bonding of the bonding wire. Furthermore, the surface roughness (Ra) of the roughened Ni plating thus obtained is 0.1 to 0.8 μm, and the resin adhesion strength at this time is 22 to 25 MPa.

[0005] For example, Patent Document 2 discloses a plating solution containing 200 g / L of copper sulfate pentahydrate, 25 g / L of sulfuric acid, 400 ppm of hydrochloric acid, 13.75 wt % of an inhibitor, and 7.5 wt % of an accelerator, which is said to form a roughened surface with excellent adhesion to the mold resin through a simple process.

[0006] JP 2007-009334 A JP 2022-127982 A

[0007] An object of the present invention is to provide a novel copper coating.

[0008] As a result of extensive research, the inventors have developed a copper film to be formed on a lead frame made of a copper alloy, which has a specific specific surface area and therefore has excellent adhesion between the lead frame and the molding resin.

[0009] That is, the present invention includes the following copper coating:

[0010] Item 1. A copper film formed on a metal lead frame, with a specific surface area of ​​1.3 x 10 -3 m 2 / g~2.2×10 -3 m 2 / g, wherein the particle aggregates forming the particle aggregate coating have a size of 15 μm or less.

[0011] Item 2. The copper coating according to Item 1, having an arithmetic mean height (Sa) of 1.3 μm to 3.0 μm (measured with a laser microscope).

[0012] The copper film of the present invention is a copper film formed on the lead frame of a semiconductor device and on the metal parts of a circuit board, and is a copper film that enhances adhesion between the molding resin and the bonding wire.

[0013] The present invention can provide a new copper coating.

[0014] 1 is a schematic diagram showing the structure of a lead frame to be subjected to roughening plating treatment; 2 is a diagram showing a method for adhesive strength testing; 3 is an electron microscope photograph showing a copper film (A) of the present invention (Example) and a copper film (B) of the prior art (Comparative Example). The copper film of the present invention has a specific surface area of ​​1.3 × 10 -3 m 2 / g~2.2×10 -3 m 2 1 is an electron microscope photograph showing a copper coating of the present invention (Example). The copper coating of the present invention is composed of a particle aggregate coating having a specific surface area of ​​1.3 × 10 -3 m 2 / g~2.2×10 -3 m 2 / g, and the particles (nodular particles) that form the particle assembly film have a size of 15 μm or less.

[0015] The present invention will be described in detail below.

[0016] The embodiments of the present invention are intended to provide a better understanding of the gist of the invention, and unless otherwise specified, do not limit the content of the invention.

[0017] In this specification, the terms "comprise" and "contain" are concepts that encompass all of "comprise," "consist essentially of," and "consist only of."

[0018] In this specification, when a numerical range is expressed as "A to B," it means A or more and B or less.

[0019] [1] Copper coating with a specific surface area of ​​1.3 x 10 -3 m 2 / g~2.2×10 -3 m 2 / g, and the particles forming the particle assembly film have an average particle size of 15 μm or less.

[0020] The copper film of the present invention is a copper film formed on a metal lead frame.

[0021] The copper coating of the present invention has a specific surface area of ​​1.3 × 10 -3 m 2 / g~2.2×10 -3 m 2 / g of particle aggregate coating.

[0022] The particle aggregates (nodular particles) that form the particle aggregate coating are 15 μm or less in size.

[0023] Particle aggregates with a size of 15 μm or less are formed by gathering together particles with an average particle size of 2 μm to 3 μm.

[0024] The copper coating of the present invention preferably has an arithmetic mean height (Sa) of 1.3 μm to 3.0 μm (measured with a laser microscope).

[0025] In the copper coating of the present invention, the metal forming the lead frame is preferably an alloy such as a copper alloy or an iron-nickel alloy, and more preferably a copper alloy (a lead frame made of a copper alloy).

[0026] Conventional plating methods have had problems such as the metal plating layer on the plated roughened surface peeling off from the molding resin due to thermal history, and poor adhesion between the roughened surface of the resulting metal coating and the bonding wire, resulting in low bonding strength.

[0027] In view of these problems, the present invention provides a copper coating that can form a roughened surface with excellent adhesion to a molding resin and a bonding wire by a simple process. The copper coating of the present invention exhibits good wire bonding strength.

[0028] In the present invention, when forming a copper film on a lead frame using PR (Periodic Reverse) pulse electrolysis, a first current is passed through the lead frame as an electrode for a first period to form an extremely thin copper film on the surface of the lead frame, and then a second current is passed through for a second period, the total amount of current being adjusted so as not to damage the lead frame A (the area to be molded, the area indicated by "A" in Figure 1(a)). This process is repeated a predetermined number of times to form a copper metal film with a specific specific surface area on the lead frame.

[0029] The electrolytic process for forming the copper film of the present invention is different from, for example, the conventional technology (JP 2022-127982 A) in that a first current is passed for a first period as a film formation process, and a third current is passed for a third period. There is no process, or the process is performed in an extremely short time.

[0030] Application Example 1 The copper coating of the present invention is preferably produced using copper plating containing a copper salt, an acid component, a halide ion, a sulfur-containing organic compound (accelerator), and a nonionic polyether polymer surfactant (inhibitor).

[0031] Application Example 2 In copper plating, the nonionic polyether polymer surfactant (inhibitor) is preferably polyethylene glycol (PEG), and the sulfur-containing organic compound (accelerator) is preferably bis(3-sulfopropyl)disulfide (SPS).

[0032] Application Example 3 The copper film of the present invention is produced using the PR pulse electrolysis method.

[0033] This PR pulse electrolysis method is a plating method for plating a lead frame with copper, and uses the plating solution to perform the following steps: (1) a first film formation process in which a first current is passed through the lead frame as an electrode for a first period to form a film on the surface of the lead frame; (2) after the first film formation process, a dissolution process in which a second current is passed through the lead frame as an electrode for a second period to dissolve the film; and (3) repeating these steps a predetermined number of times to plate the lead frame.

[0034] By using this plating method, (1) a copper film is formed on the surface of the lead frame, (2) the formed copper film is dissolved, and (3) a copper film is formed on the part where the copper film was dissolved, and this is repeated, thereby forming a roughened copper film (copper plating) on ​​the surface of the lead frame.

[0035] The metal forming the lead frame is preferably an alloy such as a copper alloy or an iron-nickel alloy, and more preferably a copper alloy (a lead frame made of a copper alloy).

[0036] By using this plating method, copper ions (I) can be effectively generated in the convection layer on the surface of the object to be plated, resulting in excellent adhesion between the lead frame and the generated copper film.

[0037] When a lead frame (metal material) is plated using this plating method (electrolysis conditions), the surface of the lead frame is roughened, and when the lead frame is bonded (molded) with a molding resin, a roughened surface that provides excellent adhesion between the lead frame and the molding resin can be formed.

[0038] The formed roughened surface has a higher adhesive strength with the bonding wire than copper coatings formed by conventional methods.

[0039] In the PR pulse electrolytic process, when copper plating is performed on a lead frame using the plating solution (preferably containing PEG as an inhibitor and SPS as an accelerator), large nodule-shaped particles are densely and uniformly formed on the lead frame surface. In this way, the lead frame surface is roughened, and when the lead frame is bonded with a molding resin, a roughened surface (copper film) with excellent adhesion between the lead frame and the molding resin can be formed. The formed roughened surface also provides excellent adhesion between the lead frame and the bonding wire.

[0040] Application Example 4 The copper film formed on the surface of the lead frame is a film consisting of particle aggregates (nodular particles). The copper film has a specific surface area of ​​1.3 × 10 calculated by the BET method (Brunauer, Emmet and Teller's equation). -3 m 2 / g~2.2×10 -3 m 2 / g of particle aggregate coating.

[0041] The particle aggregates that form the particle aggregate coating have a size of 15 μm or less.

[0042] Particle aggregates with a size of 15 μm or less are formed by gathering together particles with an average particle size of 2 μm to 3 μm.

[0043] The nodular particles of the present invention refer to particles having a balloon or bubble shape in which the cross-sectional area of ​​at least a portion of the upper part is larger than the cross-sectional area of ​​the bottom part, i.e., a so-called undercut shape. The nodular particles also include particles in which a plurality of such nodular particles grow continuously (particle aggregate film).

[0044] The copper coating preferably has an arithmetic mean height (Sa) measured by a laser microscope of 1.3 μm to 3.0 μm, more preferably 1.5 μm to 3.0 μm.

[0045] Large nodular particles are densely and uniformly formed on the surface of the lead frame.When the surface of the lead frame is roughened and the lead frame is bonded (molded) with a molding resin, a roughened surface (copper film) with excellent adhesion between the lead frame and the molding resin can be formed.The formed roughened surface also has excellent adhesion between the lead frame and the bonding wire.

[0046] Application Example 5 The copper film is preferably formed by a sintering method in which metal and resin are sintered, or by electroplating a metal or resin material after making it conductive.

[0047] Conventionally, when a porous metal is produced using a sintering method, a metal-resin-containing layer containing a metal and a resin with a melting point lower than that of the metal is formed on a substrate, and the metal-resin-containing layer is subjected to a heat treatment to sinter the metal and remove the resin from the metal-resin-containing layer, thereby obtaining a porous metal body (see, for example, Supplementary Material 2017 / 221500). However, this technique has drawbacks, such as limited shapes of the resulting metal coating and the need for special equipment.

[0048] The copper film of the present invention is a copper film formed on the lead frame of a semiconductor device and on the metal parts of a circuit board, and is a copper film that enhances adhesion between the molding resin and the bonding wire.

[0049] [2] Production of Copper Film (1) Copper Plating Solution (Copper Sulfate Plating Solution) for Forming Copper Film The copper plating solution preferably contains a copper salt (copper(II) ions), an acid component, a halide ion, a sulfur-containing organic compound, and a nonionic polyether polymer surfactant.

[0050] The concentration of copper (II) ions in the plating solution is preferably adjusted to a range of 50 g / L to 270 g / L. Copper sulfate is preferably used as the copper salt (copper (II) ions), and is used at a concentration of 200 g / L to 250 g / L as copper sulfate.

[0051] The concentration of the acid component in the copper plating solution may be any concentration sufficient to obtain electrical conductivity, and is adjusted to a range of preferably 0 g / L to 100 g / L, more preferably 0 g / L to 50 g / L. The acid component is preferably sulfuric acid.

[0052] The concentration of halide ions in the copper plating solution is preferably adjusted to within the range of 10 mg / L to 500 mg / L, more preferably 300 mg / L to 400 mg / L (300 ppm to 400 ppm).The halide ions are preferably chloride ions.

[0053] The concentration of the sulfur-containing organic compound in the copper plating solution is adjusted to preferably within the range of 0.5 mg / L to 50 mg / L, more preferably 1 mg / L to 5 mg / L.

[0054] The sulfur-containing organic compound (accelerator) is preferably bis(3-sulfopropyl)disulfide (SPS), and sulfur compounds such as 3-mercaptopropanesulfonic acid and its sodium salt, bis(3-sulfopropyl)disulfide and its disodium salt, and N,N-dimethyldithiocarbamic acid (3-sulfopropyl) ester and its sodium salt are preferably used.

[0055] The sulfur-containing organic compound may be used alone or in the form of a mixture (blend) of two or more kinds.

[0056] The concentration of the nonionic polyether polymer surfactant in the copper plating solution is preferably adjusted to within the range of 0.01 g / L to 10 g / L (more preferably, 150 mg / L to 300 mg / L).

[0057] The nonionic polyether polymer surfactant (inhibitor) is preferably polyethylene glycol (PEG). The average molecular weight of the PEG used is preferably about 600 to 6,000, more preferably about 1,000 to 4,000. The nonionic polyether polymer surfactant (inhibitor) is preferably a polyether compound such as polypropylene glycol, polyethylene oxide, or polyoxyalkylene glycol.

[0058] The nonionic polyether polymer surfactant may be used alone or in the form of a mixture (blend) of two or more of these nonionic polyether polymer surfactants.

[0059] (2) Copper Plating Method for Forming Copper Film Pulse Conditions In the copper plating method using PR pulse electrolysis, the acidic copper plating solution is used, and the object to be plated is used as the cathode, and a PR pulse current is passed through to perform electrolytic copper plating.

[0060] The conditions for applying a PR pulse current using a copper plating solution are as follows: the current density of the positive electrolysis for depositing the copper plating film is preferably 0.5 ASD (A / dm 2 ) ~ 200ASD (A / dm 2 ), more preferably about 75ASD to 100ASD, and even more preferably 40ASD to 60ASD.

[0061] The conditions for applying a PR pulse current using a copper plating solution are such that the current density of the negative electrolysis for dissolving the copper plating film is preferably 0.2 ASD to 100 ASD, more preferably about 20 ASD to 50 ASD, and even more preferably 20 ASD to 35 ASD.

[0062] The positive current application time (current time for depositing copper on the object to be plated, positive electrolysis time) is preferably about 10 milliseconds to 1,000 milliseconds (msec), more preferably about 50 milliseconds to 300 milliseconds, and even more preferably about 85 milliseconds to 120 milliseconds.

[0063] The negative current application time (current time for dissolving copper from the object to be plated, negative electrolysis time) is preferably 0.1 milliseconds to 100 milliseconds, more preferably 4 milliseconds to 25 milliseconds (even more preferably 10 milliseconds to 15 milliseconds).

[0064] The copper plating method by PR pulse electrolysis is preferably carried out under PR pulse electrolysis conditions in which the positive current application time is 50 milliseconds to 300 milliseconds and the ratio of the positive current / negative current application time (positive current application time / negative current application time) is 7 or more and less than 30.

[0065] Compared to the prior art (JP 2022-127982 A), the prior art uses a first current as a film-breaking current that dissolves the object to be plated (cathode) and a second current as a current that deposits copper on the object to be plated. Furthermore, after the first and second currents are applied for a first and second period, respectively, the potential difference between the anode and cathode is maintained at 0 V for 50 ms (a third period) to form a film.

[0066] Plating process (1) Pretreatment Pretreatment is performed on the lead frame. Pretreatment involves degreasing and pickling. Oil, metal powder, and other contaminants adhering to the surface of the copper alloy lead frame are removed to create a clean surface suitable for plating.

[0067] The pretreatment preferably includes soft etching, degreasing, and pickling.

[0068] (2) Formation of copper film Using the lead frame as the cathode and an insoluble anode (iridium (Ir) coated) as the anode, a current (first current) having a current density preferably in the range of about 0.5 ASD to 200 ASD, more preferably about 75 ASD to 100 ASD, is passed for a period (first period) preferably of about 10 milliseconds (msec) to 1,000 msec, more preferably of about 50 msec to 300 msec.

[0069] (3) Destruction of the Copper Film (Copper Ion (I) Generation Period) Next, a current (second current) having a current density of preferably about 0.2 ASD to 100 ASD, more preferably about 30 ASD to 50 ASD, is passed for a period of preferably about 0.1 milliseconds (msec) to 100 msec, more preferably about 4 msec to 25 msec (second period).

[0070] (4) A copper film is formed, and the formed copper film is repeatedly dissolved. (2) and (3) are carried out so that the specific surface area of ​​the copper film (copper plating) formed on the lead frame is 1.3 × 10 -3 m 2 / g~2.2×10 -3 m 2This process is repeated a predetermined number of times to obtain a copper coating made of a particle assembly film having a mean particle diameter of 15 μm or less.

[0071] Lead frame structure (Fig. 1) The structure of a lead frame 10, which is a metal material that is the target of the roughening plating treatment, will be described with reference to Fig. 1. Fig. 1 shows a schematic structure of the lead frame 10 that is the target of the roughening plating treatment. Fig. 1(a) is a plan view, and Fig. 1(b) is a cross-sectional view of an integrated circuit 3 in which the lead frame 10 is packaged in mold resin 30.

[0072] The lead frame 10 is made of a copper alloy and includes a die pad 11 that supports and fixes the semiconductor element 5, inner leads 13 that are connected to the wiring (bonding wires 12) of the semiconductor element 5, and outer leads 14 that bridge the wiring to the external wiring.

[0073] As shown in Fig. 1(b), the lead frame 10 is molded with a molding resin 30 to become an integrated circuit 3 such as an IC. In order to reliably remove resin burrs that occur during this resin molding, only the area of ​​the lead frame 10 that will be molded (area indicated by "A" in Fig. 1(a)) is subjected to a roughening plating treatment, and the area that will not be molded is not subjected to the roughening plating treatment.

[0074] The present invention will be specifically described below with reference to examples.

[0075] The present invention is not limited to the following specific examples.

[0076] [1] Roughening plating treatment for lead frames

[0077]

[0078] Adhesion strength test (Figure 2) The method for the adhesion strength test is explained based on Figure 2.

[0079] (1) A 1 cm square test piece (lead frame (metal material) 10) is cut from the roughened plated test frame 10 to create individual pieces. (2) Molding resin 30 is formed with the roughened plated surface facing up. (Conditions) Time: 90 seconds + α, Temperature: 180°C. (3) Drying is allowed. (Conditions) Time: 8 hours, Temperature: 175°C. (4) An environmental acceleration test is performed by placing the test piece in a constant temperature and humidity chamber. (Conditions) Time: 168 hours, Temperature: 88°C, Humidity: 85% (Environmental acceleration test JEDEC standard MSL1 compliant). (5) A reflow heating test is performed. (Conditions) Number of times: 10, Time: 1 minute → 1 minute, Temperature: 180°C to 190°C → 230°C to 240°C (Environmental acceleration test JEDEC standard MSL1 compliant). (6) A shear strength test is performed.

[0080] In the shear test, as shown in Fig. 2, a lead frame (metal material) 10 is placed on a base 40 as a test piece, and a force is applied by pressing the side of molded resin 30 molded on top of it with a tool 41 (indicated by the arrow in Fig. 2). The pressure at which molded resin 30 peels off from the test piece is taken as the adhesion strength.

[0081] Specific surface area measurement (Kr gas adsorption method) Sample: Copper film Measurement and analysis equipment: Micromeritics 3Flex (specific surface area measurement equipment) Micromeritics Smart VacPrep (pretreatment equipment) Measurement and analysis method: The copper film is collected in a large special cell and subjected to a reduced pressure degassing treatment at 110°C for 6 hours using a pretreatment equipment, after which the specific surface area is measured using Kr gas.

[0082] The molecular cross-sectional area of ​​Kr gas is 0.202 nm 2 Set to.

[0083] Measurement analysis results: Measurements are performed up to approximately P / Po = 0.3.

[0084] [2] Evaluation of copper film Comparative example copper film (Figure 3 (B)) Figure 3 (B) is a 2,500x magnification of the surface of a lead frame plated using the method described in the prior art (JP 2022-127982 A) (Comparative example copper film).

[0085] In the copper film of the comparative example, irregularly sized particles were randomly formed on the surface of the lead frame.

[0086] The copper coating of the comparative example had an arithmetic mean height (Sa) of 2.7 μm to 3.0 μm.

[0087] The copper film of the comparative example had a wire bonding strength of 50 mN to 60 mN.

[0088] The copper coating of the comparative example had a resin adhesion strength of 25 MPa to 30 MPa.

[0089] Copper coating of the example (Figs. 3(A) and 4) Fig. 3(A) shows a photograph of the surface morphology of a lead frame that has been subjected to the roughening plating treatment of the present invention, observed with an electron microscope (copper coating of the example). Fig. 3(A) is a 2,500x magnification of the surface of a lead frame that has been plated using the plating solution and the roughening plating method (PR pulse electrolysis).

[0090] The copper film of the example had a large number of nodular particles formed uniformly and at a high density.

[0091] On the surface of the lead frame subjected to the roughening plating (copper film) of the example, a copper film consisting of nodular particle aggregates with sizes of approximately 5 μm to 10 μm was formed. The copper film of the example was a copper film (particle aggregate film) in which three-dimensional nodular particles, which were formed by forming even smaller nodular particles than the nodular particles, were densely and regularly connected.

[0092] The copper film formed on the surface of the lead frame in this example is composed of a particle aggregate film (nodular particles), and the specific surface area calculated by the Kr gas adsorption method (BET method) is 1.3 × 10 -3 m 2 / g~2.2×10 -3 m 2 The particles forming the particle assembly coating had an average particle size of 15 μm or less.

[0093] The arithmetic mean height (Sa) of the copper coating in the examples was 2.0 μm to 2.8 μm.

[0094] The nodular particles in the examples refer to particles having a balloon or bubble shape, in which the cross-sectional area of ​​at least a portion of the upper part is larger than the cross-sectional area of ​​the bottom part, i.e., a shape with a so-called undercut. The nodular particles also include those in which a plurality of such nodular particles grow continuously.

[0095] The wire bonding strength of the copper film of the example was 70 mN to 80 mN.

[0096] The resin adhesive strength of the copper coating of the examples was 30 MPa to 37 MPa.

[0097]

[0098] [3] Industrial Applicability When the roughening plating method according to the present invention is used, it is possible to produce a copper coating in which regularly shaped nodular particles are densely and regularly formed on the surface of a lead frame.

[0099] The copper coating of the present invention has a high specific surface area, and therefore, when molding is carried out with a molding resin, the molding resin penetrates between the nodular particles and exhibits an anchoring effect.

[0100] Compared to the prior art, the copper coating of the present invention has strong adhesion to the bonding wire during wire bonding because the coating particles form a nodular particle aggregate coating.

[0101] The copper coating of the present invention allows a larger amount of molding resin to be filled between the nodular particle aggregate coatings than particles formed using conventional roughening plating methods, such as needle-shaped, conical, or pyramidal particles, and the adhesion strength of the molding resin to the plating layer is high.

[0102] The copper coating of the present invention also has high adhesive strength to bonding wires.

[0103] 3 Integrated circuit 5 Semiconductor element 10 Lead frame 11 Die pad 12 Bonding wire 13 Inner lead 14 Outer lead 30 Molding resin 40 Base 41 Tool

Claims

1. A copper film formed on a metal lead frame, Specific surface area is 1.6 x 10 -3 m 2 / g, exceeding 2.2 × 10 -3 m 2 / g or less, A copper coating, wherein the particle aggregates forming the particle aggregate coating have a size of 15 μm or less.

2. 2. The copper coating of claim 1, having an arithmetic mean height (Sa) of 1.3 μm to 3.0 μm.

3. A method for producing a copper film using a copper plating solution by a PR pulse electrolysis method, comprising the steps of: The copper plating solution contains a copper salt, an acid component, a halide ion, a sulfur-containing organic compound, and a nonionic polyether polymer surfactant; The PR pulse electrolysis method uses a lead frame as a cathode, (1) a first film formation process in which a first current having a current density of 0.5 ASD to 200 ASD is applied for a first period of 10 milliseconds to 1,000 milliseconds using the plating solution and the lead frame as an electrode to form a film on the surface of the lead frame; (2) after the first film formation process, a dissolution process is performed by passing a second current having a current density of 0.2 ASD to 100 ASD for a second period of 0.1 milliseconds to 100 milliseconds through the lead frame as an electrode to dissolve the coating; (3) plating the lead frame with copper by repeating the process a predetermined number of times; The lead frame has a specific surface area of ​​1.3×10 -3 m 2 / g~2.2×10 -3 m 2 13. A method for forming a copper coating comprising a particle aggregate coating having a copper content of 1000 ppm or less and a particle aggregate coating having a copper content of 1000 ppm or less and a particle aggregate coating having a copper content of 1000 ppm or less.

4. In the copper plating solution, the concentration of copper(II) ions derived from the copper salt is 50 g / L to 270 g / L; The concentration of the acid component is 0 g / L to 100 g / L; The concentration of the halide ions is 10 mg / L to 500 mg / L. The concentration of the sulfur-containing organic compound is 0.5 mg / L to 50 mg / L; 4. The method of claim 3, wherein the concentration of the non-ionic polyether polymeric surfactant is 0.01 g / L to 10 g / L.

5. In the copper plating solution, The copper salt is copper sulfate, the acid component is sulfuric acid; the halide ion is a chloride ion, The sulfur-containing organic compound is at least one component selected from the group consisting of bis(3-sulfopropyl)disulfide (SPS), 3-mercaptopropanesulfonic acid and its sodium salt, bis(3-sulfopropyl)disulfide and its disodium salt, and N,N-dimethyldithiocarbamic acid (3-sulfopropyl) ester and its sodium salt; The method according to claim 3, wherein the nonionic polyether polymer surfactant is at least one component selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol, polyethylene oxide, and polyoxyalkylene glycol.

6. In the PR pulse electrolysis method, The lead frame is used as a negative electrode or a cathode, The (1) first film formation process includes passing the first current having a current density of 40 ASD to 200 ASD; The method according to claim 3, wherein the dissolution treatment (2) comprises passing the second current having a current density of 0.2 ASD to 35 ASD.

7. Wire bonding, comprising forming the copper film according to claim 1 or the copper film produced by the method according to claim 3 on a lead frame, and wiring the lead frame and a semiconductor element via bonding wires.

8. 10. An integrated circuit, a circuit board, or a semiconductor device comprising a lead frame having a copper coating according to claim 1, or a lead frame having a copper coating produced by the method according to claim 3.