KR20220006033A - Copper surface processing equipment - Google Patents

Abstract

An object of the present invention is to provide a novel copper surface processing apparatus. A processing apparatus of the present invention is an apparatus for processing the surface of an object having a surface covered with copper, comprising a first tank for oxidizing the surface and a second tank for applying an electrolytic plating treatment to the oxidized surface processing equipment to be used.

Description

Copper surface processing equipment

The present invention relates to an apparatus for processing copper surfaces.

The copper foil used for a printed wiring board is calculated|required adhesiveness with resin. In order to improve this adhesiveness, the method of roughening the surface of copper foil by etching etc. and raising the physical adhesive force has been used. However, planarization of the surface of copper foil has come to be calculated|required from a viewpoint of densification of a printed wiring board, or a viewpoint of the transmission loss in a high frequency band. In order to satisfy these conflicting needs, a copper surface treatment method, such as performing an oxidation process and a reduction process, has been developed (WO2014/126193 Publication). According to this, the copper foil is pre-conditioned and immersed in a chemical solution containing an oxidizing agent to oxidize the copper foil surface to form concavities and convexities of copper oxide, and then immersed in a chemical solution containing a reducing agent to reduce copper oxide, thereby reducing the surface unevenness to adjust the roughness of the surface. Furthermore, as a method of improving the adhesion in the treatment of copper foil using oxidation/reduction, a method of adding surface-active molecules in an oxidation step (Japanese Patent Application Laid-Open No. 2013-534054) or an aminothiazole-based method after a reduction step A method of forming a protective film on the surface of copper foil using a compound or the like (Japanese Patent Laid-Open No. 8-97559) has been developed. Further, a method of roughening the surface of a copper conductor pattern on an insulating substrate and forming a plating film having metal particles discretely distributed by chemical plating on the surface on which a copper oxide layer is formed (Patent Document 4) ) has been developed.

In general, metal oxides have a higher electrical resistance compared to non-oxidized metals. For example, the resistivity of pure copper is 1.7×10 ⁻⁸ (Ωm), while copper oxide has a resistivity of 1 to 10 (Ωm) and cuprous oxide is 1×10 ^{6 to} 1×10 ⁷ (Ωm), and copper oxide , and cuprous oxide both have inferior conductivity compared to pure copper. Therefore, when oxidation treatment was used to roughen the surface of copper foil, chemical plating was used instead of electrolytic plating as the plating method (Japanese Patent Laid-Open No. 2000-151096). On the other hand, when the copper foil surface is roughened by making copper particles adhere to copper foil by electroplating, since an oxide does not exist in the copper foil surface, by electroplating again, the roughening treatment surface of copper foil can be plated with other metals (Patent No. 5764700; Patent No. 4948579).

It is calculated|required that a plating film has the adhesiveness of the level which endures the use and environment, and does not interfere practically. As this method, it is known that the metal bond is strengthened by removing the oxide layer on the metal surface, while the stress is dispersed by roughening the surface to ensure adhesion (“Adhesiveness and adhesion of plating film” by Tsutomu Morikawa, Takuo Nakade and Masayuki Yokoi How to improve it”).

An object of the present invention is to provide a novel copper surface processing apparatus.

In general, when an oxide layer is present on the metal surface, electrolytic plating is not directly performed for reasons such as poor conductivity or difficult to obtain adhesion between the metal foil and the plated metal layer, but after removing the oxide by acid treatment, etc. . This is because, in general, it is known that the adhesion between the metal and the plated metal layer is secured by metal bonding, and the presence of an oxide layer at the interface of the metal inhibits the metal bonding between the metal and the plated metal, making it difficult to obtain adhesion. to be. In addition, when the metal is smooth, stress propagates so that stress is concentrated at the interface between the metal and the plated metal, and interfacial peeling tends to occur.

On the other hand, in an interface with irregularities, there is no clear surface that transmits stress, unlike a smooth surface. At the time of propagation of energy, a part thereof is thought to act to deform the plated metal or metal, energy is consumed there, and adhesion is increased.

As a result of earnest research by the present inventors, by making the average oxide layer formed on the copper surface 400 nm or less by the processing apparatus of the present disclosure, we succeeded in coating a metal on the surface of the oxide layer by electroplating, thereby It became possible to raise the adhesive force of a metal and a plated metal by the anchor effect by having a fine grooving|roughness shape, while suppressing the inferiority of electrical conductivity and the inhibitory influence of a metal bond to a minimum. Conventionally, a technique and apparatus for performing an oxidation treatment, a reduction treatment, or an electrolytic plating treatment on a copper surface already exist, but a treatment technique for performing an electrolytic plating treatment after performing the oxidation treatment does not exist, and the processing thereof The device doesn't even exist. Then, the present inventors came to complete invention of the novel copper surface processing apparatus.

An embodiment of the present invention provides an apparatus for processing the surface of an object having a surface covered with copper, comprising a first tank for oxidizing the surface and a second tank for electrolytic plating on the oxidized surface be prepared The second set may include an anode and a power supply. A third tank may be provided for performing an alkali treatment on the surface using an aqueous alkali solution before oxidizing the surface. After oxidizing the surface, before electrolytic plating treatment, a fourth tank for reducing the oxidized surface with a reducing agent and/or a fifth tank for dissolving the oxidized surface with a dissolving agent may be provided. The object may be copper foil, copper particles, copper powder or a copper-plated object.

==Cross reference to related literature==

This application claims the priority based on Japanese Patent Application No. 2019-089118 for which it applied on May 9, 2019, and shall be incorporated in this specification by referring the said basic application.

ADVANTAGE OF THE INVENTION By this invention, it became possible to provide the novel copper surface processing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the 1st tank for oxidizing the surface in one Embodiment of this invention, and the 2nd tank for giving an electrolytic plating process to the oxidized surface.
It is a schematic diagram of the whole processing apparatus of one Embodiment of this invention.
3 : is a schematic diagram of the roll for conveyance provided between each set in one Embodiment of this invention.
It is a schematic diagram of the squeeze roll provided in the roll for conveyance in one Embodiment of this invention.
5 : is a schematic diagram of the guide roll provided in the roll for conveyance in one Embodiment of this invention.
It is a figure which shows the relationship between the thickness of an oxide layer and peeling strength in an Example and a comparative example.
It is a figure which shows the relationship between the thickness of an oxide layer and heat-resistant deterioration rate in an Example and a comparative example.
It is a figure which shows the relationship between the thickness of an oxide layer and heat-resistant discoloration (DELTA)E*ab in an Example and a comparative example.

Hereinafter, embodiments of the present invention will be described in detail with reference to Examples. In addition, the objects, features, advantages and ideas of the present invention are apparent to those skilled in the art from the description of the present specification, and those skilled in the art can easily reproduce the present invention from the description of the present specification. The embodiments and specific examples of the present invention described below represent preferred embodiments of the present invention, are presented for illustration or description, and do not limit the present invention thereto. It is apparent to those skilled in the art that various modifications can be made based on the description of the present specification within the spirit and scope of the present invention disclosed herein.

==Configuration of the device for machining copper surfaces==

One embodiment of the present invention is an apparatus 100 for processing an object having a surface covered with copper, at least a first tank 4 for oxidizing the surface, and electrolytic plating on the oxidized surface Article 2 (7) is provided for Before the first tank (4), a third tank (1) for performing alkali treatment on the copper surface using an aqueous alkali solution may be installed. Furthermore, following Article 3 (1), Article 6 (2) for carrying out acid cleaning treatment and Article 7 (3) for performing mild alkali treatment may be provided. And Article 1 (4) is followed, and thereafter, between Article 2 (7), Article 8 (5) for reducing the oxidized copper surface with a reducing agent and/or the oxidized copper surface with a dissolving agent Article 9 (6) for dissolving may be provided. One or more washing tanks may be installed between each bath and/or at the beginning and end of the entire treatment. Moreover, it is preferable that each tank is equipped with a heating part and a timer, and by these, the temperature and time of the process in each tank can be set. Hereinafter, the role of each tank in the processing of a copper surface is demonstrated, providing all tanks other than a water washing tank one by one, and referring FIG. 2 which is a schematic diagram of the whole apparatus at the time of using a roll-to-roll conveyance system. In addition, this apparatus structure is an example, and the structure which a person skilled in the art can understand from this indication shall all be included in the technical scope of this invention. For example, in FIG. 2, although one set of each type was provided, you may provide each two or more.

In addition, when processing the copper member continuously, such as in a roll-to-roll conveying system, etc., energization to the copper member for electrolytic plating is performed from the roll, but the energized portion is used in the second tank ( It is not limited to just before or immediately after 7), and electricity may be supplied from rolls of other sets.

In Article 3 (1), alkali treatment is performed on the copper surface using an aqueous alkali solution. Therefore, Article 3 (1) is made of a material resistant to the alkali used. This alkali treatment is performed for the purpose of degreasing.

In Article 6 (2), in order to remove the natural oxide film and reduce the treatment unevenness, the copper surface is cleaned with acid. Therefore, Article 6 (2) is made of a material resistant to the acid used.

In Article 7 (3), alkali treatment is performed on the copper surface using a weak alkali solution in order to reduce the treatment unevenness and to prevent the acid used in the washing treatment from mixing into the oxidizing agent. Therefore, Article 3 (1) is made of a material resistant to the alkali used.

In Article 1 (4), an oxidation treatment of oxidizing the copper surface using an alkali solution containing an oxidizing agent to form an oxide on the copper surface is performed. Therefore, Article 1 (4) is made of a material resistant to the oxidizing agent and alkali used. Article 1 (4) may have a mechanism in which only a portion of the surface of the copper member is subjected to oxidation treatment. For example, a copper member may be conveyed horizontally with respect to a solution surface, and it can also be made so that an unprocessed surface does not come into contact with a liquid. Alternatively, a liquid-retaining member (for example, a sponge) capable of containing an alkaline solution containing an oxidizing agent is disposed in the first tank 4 so that the copper member is not directly infiltrated into the solution, and the copper member It is also possible to oxidize only a portion of the surface of the liquid retaining member by contacting it.

In Article 8 (5), reduction treatment is performed on the oxidized copper surface using an alkali solution containing a reducing agent. This is for reducing the copper oxide formed in copper foil, and adjusting the number and length of unevenness|corrugation. Therefore, Article 8 (5) is made of a material resistant to the reducing agent and alkali used.

In Article 9 (6), a dissolution treatment of dissolving the oxidized copper surface with a dissolving agent is performed. Therefore, Article 9 (6) is made of a material resistant to the solvent used. The purpose of the dissolution treatment is to adjust the convexities on the surface of the oxidized copper.

In Article 2 (7), electrolytic plating is made with respect to the copper surface with metals other than copper. Article 2 (7) includes an anode and a power source for electrolysis. The type of the anode is not particularly limited, and may be an insoluble anode such as a pB plate or a noble metal oxide film Ti, but may be a soluble anode that itself is dissolved and electrodeposited on a copper foil or the like.

The water in the water washing tank can be heated to the same or close temperature as the tank before and after, whereby wrinkles due to the difference in thermal expansion can be prevented.

The solution used in tanks other than the second tank may be collected in a tank to immerse the copper surface, and may be sprayed onto the copper surface by a shower device provided in the tank. If the solution is collected in a tank, it is preferable to install a liquid circulation device in the tank. Thereby, the process nonuniformity by a solution can be reduced.

In FIG. 2, assuming the case where copper surfaces, such as copper foil, are processed, conveyance between the tanks of copper foil is using the roll-to-roll conveyance system. An enlarged view of the roll 11 is shown in FIG. 3 . Although the conveyance conditions in this case are not specifically limited, For example, the line speed of copper foil may be 50-3000 m/hr, and the tension of copper foil may be 1-130 kgf/m. In this system, a squeeze roll 12 as shown in FIG. 4 may be provided. Thereby, a liquid can be squeezed out of copper foil, and it reduces that a liquid enters into the next tank. Moreover, the guide roll 13 as shown in FIG. 5 can also be provided. Thereby, generation|occurrence|production of a vertical wrinkle and the fracture|rupture of copper foil can be prevented.

The conveyance between the sets of objects having a copper surface to be treated is not limited to a roll-to-roll conveying system, and may be performed manually or with a conveyor such as a belt conveyor.

A drying device may be installed to dry the copper surface after all processes have been completed. The drying temperature is not particularly limited, but the copper surface may be dried at room temperature to about 230°C.

==Processing method of copper surface==

A method of processing a copper surface using the above-described processing apparatus is described. Here, in order to process the copper surface only for the part which needs to be processed, only that part may be processed by immersing only that part in each liquid, etc. In addition, in order to perform electrolytic plating only on one surface of copper foil etc., what is necessary is just to use a well-known method (Unexamined-Japanese-Patent No. 2010-236037; Unexamined-Japanese-Patent No. 2004-232063).

First, in Article 3 (1), alkali treatment is performed on the copper surface using an aqueous alkali solution. Although the method of alkali treatment is not specifically limited, Preferably it is 30-50 g/L, More preferably, 40 g/L aqueous alkali solution, for example, sodium hydroxide aqueous solution, 30-50 degreeC, 0.5 to 2 minutes of treatment is carried out Do it. After that, it is preferable to wash the copper surface with water.

Next, in Article 6 (2), an acid cleaning treatment may be performed on the alkali-treated copper surface. For example, what is necessary is just to immerse the copper surface in 20-50 degreeC liquid temperature, 5 to 20 weight% of sulfuric acid for 1 to 5 minutes. After that, it is preferable to wash the copper surface with water.

Next, in Article 7 (3), a weak alkali treatment may be performed on the copper surface. Although the method of this alkali treatment is not specifically limited, Preferably it is 0.1-10 g/L, More preferably, it is an aqueous alkali solution of 1-2 g/L, for example, sodium hydroxide aqueous solution, 30-50 degreeC, 0.5-2. What is necessary is just to treat the copper surface for about a minute. After that, it is preferable to wash the copper surface with water.

In addition, before oxidizing the copper surface, as a pretreatment, the copper surface may be physically roughened by etching or the like.

Thereafter, in the first section (4), an oxidation treatment of oxidizing a part or all of the copper surface using an oxidizing agent to form an oxide on the copper surface is performed. An oxidizing agent is not specifically limited, For example, aqueous solutions, such as sodium chlorite, sodium hypochlorite, potassium chlorate, and potassium perchlorate, can be used. Various additives (for example, phosphate salts such as trisodium phosphate dodecahydrate) or surface active molecules may be added to the oxidizing agent. Examples of the surface-active molecules include porphyrins, porphyrin large ring, expanded porphyrin, ring-reduced porphyrin, linear porphyrin polymer, porphyrin sandwich coordination complex, porphyrin sequence, silane, tetraorgano-silane, aminoethyl-aminopropyl-tri Methoxysilane, (3-aminopropyl)trimethoxysilane, 1-[3-(trimethoxysilyl)propyl]urea (l-[3-(Trimethoxysilyl)propyl]urea), (3-aminopropyl)tri Ethoxysilane, ((3-glycidyloxypropyl)trimethoxysilane), (3-chloropropyl)trimethoxysilane, (3-glycidyloxypropyl)trimethoxysilane, dimethyldichlorosilane, 3 -(trimethoxysilyl)propyl methacrylate, ethyltriacetoxysilane, triethoxy(isobutyl)silane, triethoxy(octyl)silane, tris(2-methoxyethoxy)(vinyl)silane, chloro trimethylsilane, methyltrichlorosilane, silicon tetrachloride, tetraethoxysilane, phenyltrimethoxysilane, chlorotriethoxysilane, ethylene-trimethoxysilane, amine, sugar, and the like can be exemplified. Moreover, solvents, such as alcohol, a ketone, and carboxylic acid, can be used together as an oxidizing agent. Although the oxidation reaction conditions are not specifically limited, It is preferable that it is 40-95 degreeC, and, as for the liquid temperature of an oxidizing agent, it is more preferable that it is 40-90 degreeC. It is preferable that it is 0.5-30 minutes, and, as for reaction time, it is more preferable that it is 1-10 minutes.

By this oxidation treatment, the average is 400 nm or less. Preferably it is set as an average of 200 nm or less, More preferably, it is set as an average of 160 nm or less. Furthermore, the thickness of the oxide layer is preferably 20 nm or more on average, more preferably 30 nm or more on average, and still more preferably 40 nm or more on average. In addition, the ratio of the region in which the thickness of the oxide layer is 400 nm or less is not particularly limited, but preferably 50% or more and 400 nm or less, more preferably 70% or more and 400 nm or less, more preferably 90% or more and 400 nm or less, It is more preferable that 95% or more are 400 nm or less, and it is still more preferable that almost 100% is 400 nm or less.

The ratio of the thickness of an oxide layer is computable by the continuous electrochemical reduction method (SERA) in 10 measurement points in an area of 10x10 cm, for example.

0.02 micrometer or more is preferable, as for arithmetic mean roughness Ra of copper oxide, 0.04 micrometer or more is more preferable, It is preferable that it is 0.20 micrometer or less, It is more preferable that it is 0.060 micrometer or less.

0.2 micrometer or more is preferable, as for the maximum height roughness Rz of copper oxide, 0.4 micrometer or more is more preferable, It is preferable that it is 1.0 micrometer or less, It is more preferable that it is 0.50 micrometer or less.

Here, the maximum height roughness Rz represents the sum of the maximum value of the peak height Zp of the contour curve y=Z(x) and the maximum value of the valley depth Zv in the reference length l. .

The arithmetic mean roughness (Ra) is the value of Z(x) (that is, the height of the mountain and the depth of the valley) in the contour curve (y = Z(x)) expressed by the following equation in the reference length (l). It represents the average of absolute values.

[Number 1]

Surface roughness Ra and Rz can be calculated by the method specified in JIS B 0601:2001 (based on international standard ISO4287-1997).

Next, in Article 8 (5), a reduction treatment may be performed on the oxidized copper surface using a reducing agent. As the reducing agent, DMAB (dimethylamine borane), diborane, sodium borohydride, hydrazine, etc. can be used, and a reducing agent, an alkaline compound (eg, sodium hydroxide, potassium hydroxide), and a solvent (eg, pure water or a buffer solution) ), it can be reduced by a known method.

Next, in Article 9 (6), a dissolution treatment of dissolving the oxidized copper surface with a dissolving agent is performed. The solubilizing agent is not particularly limited, and examples thereof include chelating agents and biodegradable chelating agents. Specifically, EDTA (ethylenediamine tetraacetic acid), DHEG (diethanol glycine), GLDA (L-glutamic acid diacetic acid/tetrasodium tetrasodium) ), EDDS (ethylenediamine-N,N'-disuccinic acid), HIDS (3-hydroxy-2,2'-iminodisuccinate sodium), MGDA (methyl glycine diacetic acid trisodium), ASDA (aspartic acid diacetic acid) tetrasodium), HIDA (N-2-hydroxyethyliminodiacetic acid disodium salt), sodium gluconate, etidronic acid (hydroxyethanediphosphonic acid), and the like can be exemplified. A solvent such as alcohol, ketone, or carboxylic acid can be used in combination with the solubilizing agent used in this step. The pH of the solubilizing agent is not particularly limited, but in acid, since the amount of dissolution is large, treatment control is difficult, treatment unevenness is likely to occur, and convex portions having a suitable Cu/O ratio are not formed. Therefore, it is preferable to be alkaline And it is more preferable that it is pH 9.0-14.0, It is more preferable that it is pH 9.0-10.5, It is more preferable that it is pH 9.8-10.2. In Article 9 (6), the copper surface is polished until the copper oxide dissolution rate is 35 to 99%, preferably 77 to 99%, and the thickness of CuO is 4 to 150 nm, preferably 8 to 50 nm. It is preferable to dissolve.

After that, in the second set (7), the copper surface is subjected to an electrolytic plating treatment with a metal other than copper. As the electrolytic plating treatment method, a known technique can be used. For example, as a metal other than copper, Sn, Ag, Zn, Al, Ti, Bi, Cr, Fe, Co, Ni, Pd, Au, Pt, Alternatively, an alloy thereof may be used. In particular, when the object having a surface covered with copper is copper foil, a metal having higher heat resistance than copper, for example, Ni, Pd, Au, Pt or an alloy thereof, is preferable in order to have heat resistance. In addition, in the case of copper foil, etc., what is plated may be one side or both sides.

Although the average thickness in the vertical direction of the metal layer formed by electroplating is not particularly limited, it is preferably 10 nm or more, more preferably 15 nm or more, and still more preferably 20 nm or more. And it is preferable that it is 100 nm or less, It is more preferable that it is 70 nm or less, It is more preferable that it is 50 nm or less.

Alternatively, the electrolytic case nd that the metal amount in the metal layer formed by plating as the weight of metal per unit area, not less than 15μg / cm ² is preferable, and more preferably from 18μg / cm ^2, more preferably not less than 20μg / cm ² . Further, it 100μg / cm ² or less is preferable, more preferably 80μg / cm ² or less, and more preferably 50μg / cm ² or less.

The average thickness in the vertical direction of the metal layer can be calculated by dissolving the metal forming the metal layer in an acidic solution, measuring the metal amount by ICP analysis, and dividing the measured amount by the area of the object. Alternatively, it can be calculated by dissolving the object itself and detecting and measuring only the amount of the metal that forms the metal layer.

Since electrolytic plating also requires an electric charge to partially reduce the oxide of the oxide layer, for example, when nickel plating is performed on copper foil, in order to put the thickness within a preferable range, per area of the object subjected to electrolytic plating, 15C / dm ² or more is desirable to impart an electrical charge of ~90C / dm ² or less.

Moreover, as for a current density, 5 A/dm<^2> or less is preferable. If the current density is too high, uniform plating is difficult, for example, plating is concentrated on the convex portions. In addition, as long as the oxide of the oxide layer is partially reduced, the current under plating can be changed. Moreover, it adjusts suitably so that it may become a predetermined thickness with the metal to coat|cover.

Nickel plating and nickel alloy plating include pure nickel, Ni-Cu alloy, Ni-Cr alloy, Ni-Co alloy, Ni-Zn alloy, Ni-Mn alloy, Ni-Pb alloy, Ni-P alloy, etc. .

As the supplying agent for plating ions, for example, nickel sulfate, nickel sulfamate, nickel chloride, nickel bromide, zinc oxide, zinc chloride, diamine dichloropalladium, iron sulfate, iron chloride, chromic anhydride, chromium chloride, sodium chromium sulfate, Copper sulfate, copper pyrophosphate, cobalt sulfate, manganese sulfate, sodium hypophosphite, etc. can be used.

Other additives including pH buffering agents and brighteners, for example, boric acid, nickel acetate, citric acid, sodium citrate, ammonium citrate, potassium formate, malic acid, sodium malate, sodium hydroxide, potassium hydroxide, sodium carbonate, ammonium chloride, cyanide Sodium, potassium stannate, potassium thiocyanate, sulfuric acid, hydrochloric acid, potassium chloride, ammonium sulfate, ammonium chloride, potassium sulfate, sodium sulfate, sodium thiocyanate, sodium thiosulfate, potassium bromate, potassium pyrophosphate, ethylenediamine, sulfuric acid Nickel ammonium, sodium thiosulfate, hydrosilicic acid, sodium silicate, strontium sulfate, cresol sulfonic acid, β-naphthol, saccharin, 1,3,6-naphthalene trisulfonic acid, naphthalene (di, tri), sodium sulfonate, 1-4 butyndiol such as sulfonamide and sulfinic acid, coumarin, and sodium lauryl sulfate are used.

In nickel plating, the composition of a bath is, for example, nickel sulfate (100 g/L or more - 350 g/L or less), sulfamine nickel (100 g/L or more - 600 g/L or less), nickel chloride (0 g/L or more) ~300 g/L or less) and mixtures thereof, but may contain sodium citrate (0 g/L or more to 100 g/L or less) or boric acid (0 g/L or more to 60 g/L or less) as additives. have.

The ratio of the metal in the metal layer other than copper is not particularly limited, but the ratio of Cu to the total amount of metal at a depth of 6 nm is preferably 80% by weight or less, more preferably 50% by weight or less, and 30% by weight or less more preferably. Moreover, it is preferable that the ratio of Cu with respect to the total amount of metals at the depth not containing oxygen is 90 % by weight or more, It is more preferable that it is 95 % by weight or more, It is still more preferable that it is 99 % by weight or more. Moreover, it is preferable that it is 1 or more, as for the Cu/O ratio at the depth where the ratio of the atomic composition of Cu is 40%, it is more preferable that it is 2 or more, It is still more preferable that it is 5 or more. The ratio of Cu to the total amount of metal at a predetermined depth can be measured using, for example, ion sputtering and X-ray photoelectron spectroscopy (XPS).

The metal layer is preferably an even layer without particles. Herein, "even" means that the thickness of the layer does not exceed 5 times the average thickness of the layer in 95% or more, preferably in 98% or more, more preferably in 99% or more plane. , Preferably it does not exceed 3 times, More preferably, it shall say that it does not exceed 2 times. By forming an even metal layer without particles, the adhesiveness after heat treatment can be improved.

In addition, after these steps, a coupling treatment using a silane coupling agent or the like or a rust prevention treatment using benzotriazoles may be performed.

It is preferable to set conditions such as temperature and time by conducting a pilot experiment in advance so as to obtain an oxide layer suitable for the purpose of use of the oxide by these series of processes.

= = Object and its surface shape = =

The object having a copper surface to be processed may be an object made of copper, one in which a layer of copper is provided on the surface of an object other than copper, or one in which copper plating is applied, but the shape of the object Although it is not specifically limited, For example, it may be foil shape, particle shape, powder shape may be sufficient, Copper foil, such as electrolytic copper foil and rolled copper foil containing copper as a main component, copper particle, copper grain (銅粒) ), a copper wire, a copper plate, or a lead frame made of copper.

By processing this copper surface with the above-mentioned processing apparatus, a convex part is formed in the surface of at least one part metal layer.

The average height of the convex portions is preferably 10 nm or more, more preferably 50 nm or more, still more preferably 100 nm or more, more preferably 1000 nm or less, more preferably 500 nm or less, and still more preferably 200 nm or less. The height of this convex part is the minimum point of the recessed part adjacent across the convex part in the scanning electron microscope (SEM) image which observed the cross section of the composite copper foil produced by the focused ion beam (FIB), for example. can be defined as the distance between the midpoint of the line segment connecting

On the surface of an object, it is preferable that it is 15 or more on average per 3.8 micrometers of convex parts 50 nm or more in height, It is more preferable that it is 30 or more, It is still more preferable that it is 50 or more. Moreover, it is preferable that it is 100 or less, It is more preferable that it is 80 or less, It is still more preferable that it is 60 or less. The number of convex portions is, for example, in a scanning electron microscope (SEM) image obtained by observing a cross section of a composite copper foil produced by a focused ion beam (FIB). It can be counted by

0.02 micrometer or more is preferable, and, as for arithmetic mean roughness Ra of a metal layer, 0.04 micrometer or more is more preferable, It is preferable that it is 0.20 micrometer or less, and it is more preferable that it is 0.060 micrometer or less.

0.2 micrometer or more is preferable, as for the maximum height roughness Rz of a metal layer, 0.4 micrometer or more is more preferable, It is preferable that it is 1.4 micrometers or less, It is more preferable that it is 0.50 micrometer or less.

The ratio of Ra after oxidation treatment to Ra after metal plating treatment (Ra after oxidation treatment/Ra after metal plating treatment) is preferably 0.7 or more to 1.3 or less, and the ratio of Rz after oxidation treatment to Rz after metal plating treatment (oxidation treatment) As for Rz after a process/Rz after a metal plating process), 0.8 or more - 1.2 or less are preferable. The closer the value of this ratio to 1, the more uniform the thickness of the metal layer formed by electroplating.

==How to use an object with a roughened copper surface==

An object having a copper surface roughened using the processing apparatus of the present disclosure can be used for a copper foil used for a printed wiring board, a copper wire wired to a substrate, a copper foil for a LIB negative electrode current collector, and the like.

For example, the surface of the copper foil used for a printed wiring board is roughened using the processing apparatus of this indication, A laminated board is produced by bonding resin and layered form, It can be used for manufacturing a printed wiring board. Although the kind of resin in this case is not specifically limited, It is preferable that it is polyphenylene ether, epoxy, PPO, PBO, PTFE, LCP, or TPPI.

Further, for example, by roughening the surface of the copper foil used for the LIB negative electrode current collector using the processing apparatus of the present disclosure, the adhesion between the copper foil and the negative electrode material is improved and the capacity deterioration is small. can get The negative electrode current collector for a lithium ion battery can be manufactured according to a known method. For example, a negative electrode material containing a carbon-based active material is prepared and dispersed in a solvent or water to obtain an active material slurry. After this active material slurry is applied to a copper foil, it is dried in order to evaporate a solvent or water. Then, after pressing and drying again, the negative electrode collector is shape|molded so that it may become a desired shape. In addition, the negative electrode material may contain silicon, a silicon compound, germanium, tin, lead, or the like having a larger theoretical capacity than the carbon-based active material. Further, as the electrolyte, not only an organic electrolyte in which a lithium salt is dissolved in an organic solvent, but also a polymer made of polyethylene oxide or polyvinylidene fluoride may be used. The copper foil which processed the surface using the processing apparatus of this indication is applicable not only to a lithium ion battery but to a lithium ion polymer battery.

Example

<1. Preparation of an object having a roughened copper surface>

Examples 1 to 9 and Comparative Examples 1 to 4 used copper foil of DR-WS (product of Furukawa Electric Co., Ltd., thickness: 18 µm). In addition, about the Example and the comparative example, the some test piece was produced under the same conditions, respectively.

(1) Pretreatment

[Alkaline degreasing treatment]

After immersing copper foil in the sodium hydroxide aqueous solution of 50 degreeC liquid temperature and 40 g/L for 1 minute, water washing was performed.

[acid washing treatment]

After immersing the copper foil which performed the alkali degreasing process in the liquid temperature of 25 degreeC, 10 weight% of sulfuric acid aqueous solution for 2 minutes, water washing was performed.

[Predip processing]

The copper foil which performed the pickling process was immersed for 1 minute in the liquid temperature 40 degreeC, and the chemical|medical solution for predip of sodium hydroxide (NaOH) 1.2g/L.

(2) oxidation treatment

Based on the conditions of Table 1, the copper foil which performed the alkali treatment was oxidized using the aqueous solution for oxidation treatments. After these treatments, the copper foil was washed with water.

The evaluation method is <2. Evaluation of the sample after oxidation treatment> will be described later.

(3) Electrolytic plating treatment

About the copper foil which performed the oxidation process, the electrolytic plating process was performed based on the conditions of Table 1. In Comparative Examples 2 and 3, nickel did not precipitate even when electroplating was performed for 3 minutes.

(4) Coupling treatment

About the copper foil which performed the electroplating process, the coupling process was performed based on the conditions of Table 1.

<2. Evaluation of samples after oxidation treatment>

(1) thickness measurement of copper oxide

The thickness of the copper oxide on the surface of copper foil was measured by the continuous electrochemical reduction method (SERA) using the following electrolyte solutions using QC-100 (made by ECI).

Electrolyte (pH=8.4)

6.18 g/L boric acid; Sodium tetraborate 9.55 g/L

^{Specifically, when the electrolyte solution was used at a current density of 90 μA/cm 2} using a gasket diameter: 0.32 cm, a potential from -0.85 V or more to -0.6 V was judged as the peak of copper oxide (CuO).

(2) Calculation of Ra and Rz

The copper foil after oxidation treatment was measured for the surface shape of the copper foil using a confocal scanning electron microscope OPTELICS H1200 (manufactured by Lasertec Corporation), Ra and Rz was calculated. As measurement conditions, the scan width was 100 µm, the scan type was area, the light source was Blue, and the cutoff value was 1/5. The object lens was x100, the contact lens was x14, the digital zoom was x1, and the Z pitch was set to 10 nm to acquire three pieces of data, and the average values thereof were Ra and Rz of each Example and Comparative Example. Since Example 6 and Comparative Examples 1-3 could not be computed, it described as N.D. in a table|surface.

<3. Evaluation of samples after electrolytic plating and coupling treatment>

(1) Calculation of nickel content

As a method for measuring the average thickness of nickel in the vertical direction, for example, a solution obtained by dissolving a copper member in 12% nitric acid is used using an ICP emission spectrometer 5100 SVDV ICP-OES (manufactured by Agilent Technologies). Then, the concentration of the metal component was measured, and the thickness of the metal layer as a layer was calculated by considering the density of the metal and the surface area of the metal layer.

(2) Calculation of Ra and Rz

The surface shape of the copper foil after electrolytic plating and coupling treatment was measured using a confocal scanning electron microscope OPTELICS H1200 (manufactured by Lasertec Corporation), and the method specified in JIS B 0601:2001 to calculate Ra and Rz. As measurement conditions, the scan width was 100 µm, the scan type was area, the light source was Blue, and the cutoff value was 1/5. The object lens was x100, the contact lens was x14, the digital zoom was x1, and the Z pitch was set at 10 nm to acquire data from three parts, and Ra and Rz were the average values of the three parts.

(3) Measurement of peel strength before and after heat treatment of laminate

About the copper foil after electroplating and a coupling process, the laminated body was produced and the peeling strength before and behind heat processing was measured. Moreover, the peeling surface was visually confirmed at the time of peeling strength measurement, and the presence or absence of peeling of a plating layer was confirmed. First, for each copper foil, MEGTRON6 (manufactured by Panasonic Corporation) containing PPE as a resin is heat-compressed and laminated under the conditions of a press pressure of 2.9 MPa, a temperature of 210° C., and a press time of 120 minutes in a vacuum, respectively. Two measurement samples were obtained. For each measurement sample, in order to check the resistance to heat, heat-resistant treatment (177° C. for 10 days) was performed. Thereafter, a 90° peel test (Japanese Industrial Standards (JIS) C5016) was performed on the sample subjected to heat treatment and the sample not subjected to heat treatment, respectively, to determine the peel strength (kgf/cm). The heat-resistance deterioration rate was computed as the ratio which divided the difference of the peeling strength before and behind the measured heat-resistance test by the peeling strength before a heat-resistance test.

Although MEGTRON6 was used as a prepreg, also in other commercially available prepregs, such as MEGTRON4, there is hardly any deterioration resulting from copper foil, and the adhesiveness before and behind the same heat treatment is obtained.

(4) Calculation of color change before and after heat treatment of copper foil

The color change also evaluated the heat resistance of the copper foil after electrolytic plating and a coupling process. Specifically, heat treatment was performed in an oven at 225° C. for 30 minutes, and the color change before and after was evaluated as ΔE*ab. After measuring the color difference (L*, a*, b*) of the copper foil before heat treatment, it was put in an oven at 225° C. for 30 minutes, and the color difference of the copper foil after heat treatment was measured, according to the following formula , ΔE*ab was calculated.

[Number 2]

As such, when the thickness of the copper oxide is 502 nm or more, electrolytic plating cannot be performed (Comparative Example 2, Comparative Example 3). Moreover, even if it is the thickness of the copper oxide which can be electrolytically plated, when the thickness of copper oxide is thicker than 400 nm, the adhesiveness of a plating layer and a metal member cannot be acquired, but peeling generate|occur|produces (comparative example 1). On the other hand, in Examples 1-9 in which the thickness of copper oxide is 400 nm or less, adhesiveness with resin and heat resistance are excellent while adhesiveness between a plating layer and a metal member was obtained.

In addition, when the current density is ^{greater than 5 A/dm 2} , the heat resistance is low (Comparative Example 4), whereas ^{Examples 1 to 9 having a current density of 5 A/dm 2} or less have excellent adhesiveness and heat resistance with the resin.

Claims (6)

An apparatus for processing an object having a surface covered with copper, said surface processing apparatus comprising:
a first bath for oxidizing the surface;
Article 2 for electrolytic plating on the oxidized surface
A processing device comprising a. The method of claim 1,
A processing apparatus characterized in that the current density of the electrolytic plating treatment in the second set is 5 A/dm ^{2 or less.} 3. The method of claim 1 or 2,
The second set includes an anode and a power supply. 4. The method according to any one of claims 1 to 3,
and a third tank for performing an alkali treatment on the surface using an aqueous alkali solution before oxidizing the surface. 5. The method according to any one of claims 1 to 4,
A processing apparatus comprising a fourth tank for reducing the oxidized surface with a reducing agent and/or a fifth tank for dissolving the oxidized surface with a dissolving agent after oxidizing the surface and before electrolytic plating treatment. 6. The method according to any one of claims 1 to 5,
The object is a copper foil, copper particle, copper powder, a copper wire, a copper plate, a copper lead frame, or a copper-plated object.

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