KR101546458B1 - Fabrication method for copper clad sheet - Google Patents

Abstract

The present invention relates to a fabrication method for a copper clad sheet, which comprises the steps of: providing an aluminum sheet; removing an oxide film formed on a surface of the aluminum sheet; and forming a copper layer using a plating method on the aluminum sheet wherein the oxide film is removed.

Description

[0001] The present invention relates to a copper clad sheet,

The present invention relates to a method for producing a copper-clad laminated sheet, and more particularly, to a method for producing a copper-clad laminated sheet capable of forming a copper foil on an aluminum sheet to be used for electromagnetic wave shielding, heat radiation plate and the like.

BACKGROUND ART [0002] Recently, metal sheets are increasingly used for materials such as an electromagnetic wave shielding material, a radiation plate for display, or a heat sink. Among these metal sheets, a copper-clad laminated sheet having a copper layer formed on an aluminum substrate is widely used.

Conventional techniques for forming a copper layer on aluminum are electrolytic copper plating and reduced copper plating. In the copper-plated laminated sheet having a copper layer formed on aluminum, there is a problem of adhesion between the aluminum and the copper layer. In the electrolytic copper plating method, complicated processes such as degreasing, pickling and sizing treatment are applied for securing the adhesion, And a composite process such as chemical treatment and neutralization treatment is applied. Such complicated processing steps increase the manufacturing cost of the copper-clad laminated sheet and cause problems such as unnecessary chemical substances being discharged.

Another plating method for forming a copper layer on aluminum is the displacement plating method. The displacement plating method is a type of electroless plating such as a reduction copper plating method, which is also referred to as an immersion plating by a plating method using a difference in ionization tendency between metals of different kinds.

Japanese Unexamined Patent Publication No. 2004-41579 discloses a prior art in which a copper layer is formed on aluminum by displacement plating. This prior art discloses a technique for forming a film of zinc or copper on the surface of a material made of aluminum or an aluminum alloy using substitution plating. However, since the process of removing the aluminum oxide film is performed simultaneously with the displacement plating, the aluminum oxide film is partially left, and the adhesion of aluminum and the copper layer is deteriorated.

Accordingly, a first object of the present invention is to provide a method of manufacturing a copper-clad laminated sheet in which an oxide film formed on the surface of aluminum is effectively removed to improve adhesion between aluminum and a copper layer.

A second object of the present invention is to provide a copper-clad laminated sheet which can be used for electromagnetic shielding, a reflection sheet, a heat-radiating sheet, and the like.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: providing an aluminum sheet; removing an oxide film formed on the surface of the aluminum sheet; forming a copper foil layer on the aluminum sheet from which the oxide film has been removed, The method comprising the steps of:

According to an embodiment of the present invention, it is preferable that the step of removing the oxide film is performed in a pH range of 8.5 to 10.5 using a strong alkali solution.

According to another embodiment of the present invention, the step of forming the copper foil layer on the aluminum sheet from which the oxide film has been removed by the plating method may be performed by a substitution plating method.

According to another embodiment of the present invention, the method of manufacturing a copper-clad laminated sheet may further include the step of attaching a polymeric resin carrier to an opposite surface of the aluminum sheet on which the copper foil layer is formed, using an adhesive.

According to another embodiment of the present invention, the displacement plating method is preferably performed in the range of pH 9.5 to 12.5.

According to another aspect of the present invention, there is provided a pressure sensitive adhesive sheet comprising a polymer resin carrier, a pressure sensitive adhesive layer formed on the polymer resin carrier, an aluminum sheet adhered on the pressure sensitive adhesive layer, and a copper foil layer formed on the aluminum sheet, Layer is formed by a displacement plating method.

The method for manufacturing a copper-clad laminated sheet of the present invention has the following effects.

1. Since the step of removing the oxide film using the strong alkaline solution is separately performed prior to performing the displacement plating, uniform plating is possible and a high adhesion force between the aluminum base and the copper layer can be realized.

2. Since a copper layer is formed on aluminum by substitution plating method, complicated processes such as degreasing, pickling, zincate treatment, catalytic treatment and neutralization treatment, which are necessary for electrolytic plating and reduction plating, are easily performed by pretreatment of alkali solution Can be performed.

3. The pretreatment process of the alkaline solution is performed in a predetermined pH range, so that the effective removal of the oxide and the prevention of the damage of the aluminum ground layer can be satisfied at the same time.

4. The process of substitution copper plating is carried out in a predetermined pH range to prevent defective plating such as smut plating or coarse film formation.

5. Since the copper layer formation process is performed only in two steps of pretreatment of alkaline solution and replacement copper plating, it can be effectively applied to environmentally-friendly, roll-to-roll mass production methods with a small amount of unnecessary chemical emissions.

1 is a flowchart showing a manufacturing process of a copper-clad laminate using an electrolytic copper plating method.
2 is a flowchart showing a manufacturing process of the copper-clad laminate using the reduced copper plating method.
3 is a flow chart showing a process sequence of a method for manufacturing a copper-clad laminated sheet of the present invention.
FIGS. 4, 5, 6, and 7 are photographs of the surface of a normal substituted copper layer, a smoothed substituted copper layer, a red coarse copper layer, a stain, and a poorly adhered copper layer.

A method for manufacturing a copper-clad laminated sheet, comprising the steps of: providing an aluminum sheet; removing an oxide film formed on the surface of the aluminum sheet; forming a copper foil layer on the aluminum sheet from which the oxide film has been removed, .

The plating method is a technique in which a metal film is formed on a surface by immersing an object to be plated in a solution containing metal ions and depositing a metal. The plating method can be divided into electrolytic plating and electroless plating. Electrolytic plating is a method in which a redox reaction is caused on the surface of an electrode while an object to be plated is used as an electrode and an electric current is supplied. Electroless plating is a method in which metal ions contained in a solution are precipitated without applying current from the outside, and then classified into reduction plating and displacement plating. Reduction plating is a plating method in which a reducing agent reduces metal ions to precipitate a metal on a plating object, and is divided into non-catalyst plating and self-catalyst plating depending on whether the catalyst is used or not. Substitution plating is also called immersion plating. It is a plating method using a potential difference between different metals. It is immersed in a solution containing metal ions having a stronger reducing power than the material metal, .

When aluminum is exposed to air, a natural oxide film is formed on the surface, so the pretreatment process of the plating is difficult. A conventional technique of forming a copper layer on aluminum using a plating method will be described as follows.

1 is a flowchart showing a manufacturing process of a copper-clad laminate using an electrolytic copper plating method. Referring to FIG. 1, first, the aluminum substrate is subjected to a degreasing process, followed by a pickling process, followed by a zincate treatment or a chromate treatment to form a thin non-reactive metal. Finally, electrolytic copper plating is performed on the non- do. The process of forming the copper layer on the aluminum substrate using the electrolytic copper plating method requires a complicated pre-treatment process, which increases the cost and causes a large amount of chemicals harmful to the environment.

2 is a flowchart showing a manufacturing process of the copper-clad laminate using the reduced copper plating method. Referring to FIG. 2, first, the aluminum substrate is degreased, then catalyzed, then neutralized and subjected to reduced copper plating. However, the reduced copper plating method can not avoid complicated pretreatment, and therefore, there is a problem that the roll-to-roll type mass production method can not be applied.

The method for manufacturing a copper-clad laminated sheet of the present invention is characterized in that a copper layer on an aluminum substrate is formed by a displacement plating method. In the present invention, since the oxide film is first removed by using a strong alkali solution as a pretreatment step of the substitution plating, the replacement plating is made uniform, and the high adhesion force between the aluminum and the copper layer Can be implemented.

3 is a flow chart showing a process sequence of a method for manufacturing a copper-clad laminated sheet of the present invention. Referring to FIG. 3, the method for manufacturing the copper-clad laminated sheet of the present invention comprises two steps of a pretreatment step and a displacement plating step. The pretreatment step is a step of removing the oxide film formed on the surface of the aluminum substrate, and is performed by immersing the aluminum substrate in the strong alkaline solution. The pretreatment solution may include calcium carbonate, potassium hydroxide, sodium hydroxide and the like as a strong alkali salt, and may further contain a surfactant. The acidity of the pretreatment solution is very important, and the acidity of the pretreatment solution is preferably in the range of pH 8.5 to 10.5. If the pH is less than 8.5, it is difficult to remove the aluminum oxide. If the pH exceeds 10.5, excessive aluminum dissolution may occur and the aluminum ground layer may be damaged. The pH of the pretreatment solution is more preferably in the range of pH 9 to 10.

The replacement copper plating step is a step of forming a copper layer while eluting aluminum from the aluminum surface from which the oxide film has been removed. The solution used for the replacement copper plating includes a copper salt and a complexing agent. The copper salt may be in the form of a sulfate salt, a nitrate salt or a chloride salt, and may be a soluble organic acid salt such as a monocarboxylic acid, a polycarboxylic acid or a hydroxycarboxylic acid, and may be a water soluble metal complex. Specific copper salts may be the same as lactic acid, chloride, copper blue, pyrophosphoric acid. The complexing agent may be a cyanide compound such as potassium cyanide or sodium cyanide. An aliphatic amine such as ethylenediamine, butylamine or tetraethylamine, or an organic acid such as formic acid or tartaric acid may be used. Basically, It is desirable that it is. The copper salt and the complexing agent are preferably mixed in a weight ratio of 1: 1 to 1: 3. The substituted copper plating solution may further comprise a pH adjusting agent. As the pH adjusting agent, strong alkaline salts such as sodium hydroxide, potassium hydroxide and the like may be used. The acidity of the substituted copper plating solution is preferably in the range of pH 9.5 to 12.5. If the acidity of the substituted copper plating solution is less than pH 9.5, smut plating may be achieved, and if pH 12.5 is exceeded, red and rough coatings may be formed on the copper plating surface. The acidity of the substituted copper plating solution is more preferably in the range of pH 10 to 12. [

The copper-clad laminated sheet produced by the method for producing a copper-clad laminate sheet of the present invention is excellent in surface gloss, electrical conductivity and heat dissipation property, and can be used for producing substrates such as semiconductors and printed circuit boards and for shielding electromagnetic waves of communication devices such as smart phones And can be used as a reflector or a heat sink for a display device or a lighting device.

In order to use the copper-clad laminated sheet for various purposes, it is advantageous to commercialize the product in a state of being adhered to a carrier. To this end, a pressure-sensitive adhesive layer is formed on a polymeric resin carrier such as PET, and an aluminum layer of a copper-clad laminate sheet is laminated on a pressure-sensitive adhesive layer to produce a copper-clad laminated sheet having a carrier. The copper-clad laminated sheet having such a carrier having such a structure can be used for various purposes such as a conductive layer of a printed circuit board, an electromagnetic wave shielding layer, a reflection plate, a heat sink, etc. by separating the carrier and the aluminum foil layer from the adhesive layer.

Hereinafter, a method for manufacturing a copper-clad laminated sheet of the present invention will be described with reference to examples.

Example 1-1 (Pretreatment)

5 g of calcium carbonate was dissolved in 1000 ml of distilled water and 1 g of Cecle MC 563 as a surfactant was added to prepare a pretreatment solution. The acidity of the pretreatment solution was pH 9. A 10 cm x 10 cm aluminum sheet (San Al aluminum AL1235) was immersed in the pretreatment solution for 5 minutes to remove the oxide film formed on the aluminum surface.

Example  1-2 (Pretreatment)

Pretreatment was carried out in the same manner as in Example 1-1, except that 7 g of calcium carbonate was dissolved in 1000 ml of distilled water to adjust the acidity of the pretreatment solution to pH 10 and the pretreatment time to 5 minutes.

Comparative Example 1-1 (Pretreatment)

Pretreatment was carried out in the same manner as in Example 1-1, except that 3 g of calcium carbonate was dissolved in 1000 ml of distilled water to adjust the acidity of the pretreatment solution to pH 8 and the pretreatment time to 10 minutes.

Comparative Example 1-2 (Pretreatment)

Pretreatment was carried out in the same manner as in Example 1-1 except that 10 g of calcium carbonate was dissolved in 1000 ml of distilled water to adjust the acidity of the pretreatment solution to pH 11 and the pretreatment time to 2 minutes.

Example 2-1 (Substitutional plating)

100 g of lactic acid, 100 g of butylamine as a complexing agent, and 2 g of sodium hydroxide as an acidity regulator were dissolved in 1000 ml of distilled water to prepare a solution for substitutional plating. At this time, the acidity of the solution for substitutional plating was pH 10. The aluminum sheet pretreated in Example 1-1 was immersed in the solution for substitutional plating for 5 minutes to form a copper layer on the aluminum surface.

Example 2-2 (Substitution plating)

100 g of lactic acid, 100 g of tetraethylamine as a complexing agent and 3 g of sodium hydroxide as an acidity regulator were dissolved in 1000 ml of distilled water to prepare a solution for substitutional plating. At this time, the acidity of the solution for substitutional plating was pH 11, and a copper layer was formed on the aluminum surface in the same manner as in Example 2-1.

Example 2-3 (Substitutional plating)

100 g of lactic acid, 100 g of ethylamine as a complexing agent and 4 g of sodium hydroxide as an acidity regulator were dissolved in 1000 ml of distilled water to prepare a solution for substitutional plating. At this time, the acidity of the solution for substitutional plating was pH 12, and a copper layer was formed on the aluminum surface in the same manner as in Example 2-1.

Example 2-4 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-1 except that the aluminum sheet pretreated in Example 1-2 was used.

Example 2-5 (Substitution plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-2, except that the aluminum sheet pretreated in Example 1-2 was used.

Example 2-6 (Substitution plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-3 except that the aluminum sheet pretreated in Example 1-2 was used.

Comparative Example 2-1 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-1 except that the aluminum sheet pretreated in Comparative Example 1-1 was used.

Comparative Example 2-2 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-2 except that the aluminum sheet pretreated in Comparative Example 1-1 was used.

Comparative Example 2-3 (Substitution Plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-3, except that the aluminum sheet pretreated in Comparative Example 1-1 was used.

Comparative Example 2-4 (Substitutional Plating)

100 g of lactic acid, 100 g of ethylenediamine as a complexing agent and 1 g of sodium hydroxide as an acidity regulator were dissolved in 1000 ml of distilled water to prepare a solution for substitutional plating. At this time, the acidity of the solution for substitutional gold was pH 9. The aluminum sheet pretreated in Example 1-1 was immersed in the solution for substitutional plating for 5 minutes to form a copper layer on the aluminum surface.

Comparative Example 2-5 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Comparative Example 2-4, except that 5 g of sodium hydroxide was dissolved in the solution for substitutional plating to adjust the acidity to pH 13. [

Comparative Example 2-6 (Substitutional plating)

100 g of lactic acid, 100 g of ethylenediamine as a complexing agent and 1 g of sodium hydroxide as an acidity regulator were dissolved in 1000 ml of distilled water to prepare a solution for substitutional plating. At this time, the acidity of the solution for substitutional gold was pH 9. The aluminum sheet pretreated in Example 1-2 was immersed in the solution for substitutional plating for 5 minutes to form a copper layer on the aluminum surface.

Comparative Example 2-7 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Comparative Example 2-6, except that 5 g of sodium hydroxide was dissolved in the solution for substitutional plating to adjust the pH to 13.

Comparative Example 2-8 (Substitution Plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-1 except that the pretreatment step was omitted.

Comparative Example 2-9 (Substitution Plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-2, except that the pretreatment step was omitted.

Comparative Example 2-10 (Substitutional plating)

A copper layer was formed on the aluminum surface in the same manner as in Example 2-3, except that the pretreatment step was omitted.

Table 1 and Table 2 below summarize the acidity of the pretreatment solution and the displacement plating solution of the examples and the comparative example.

Example 2-1 Example 2-2 Example 2-3 Examples 2-4 Example 2-5 Examples 2-6 Comparative Example 2-1 Comparative Example 2-2 Pretreatment
Solution pH pH 9 pH 9 pH 9 pH 10 pH 10 pH 10 pH 8 pH 8 Substitution plating solution pH pH 10 pH 11 pH 12 pH 10 pH 11 pH 12 pH 10 pH 11

Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 Comparative Example 2-6 Comparative Example 2-7 Comparative Example 2-8 Comparative Example 2-9 Comparative Example 2-10 Pretreatment
Solution pH pH 8 pH 9 pH 9 pH 10 pH 10 - - - Substitution plating solution pH pH 12 pH 9 pH 13 pH 9 pH 13 pH 10 pH 11 pH 12

Evaluation Example 1 (Determination of appearance of plating state)

The appearance of the copper layer formed according to Examples and Comparative Examples was observed to observe the occurrence of smut, surface color, roughness and the like.

In the examples, no smut was observed, the surface color had a normal plating color, and no ideal roughness was observed.

On the contrary, the comparative examples have smut or smudge, the surface is abnormally reddish, or has a rough surface.

FIGS. 4, 5, 6, and 7 are photographs of the surface of a normal substituted copper layer, a smoothed substituted copper layer, a red coarse copper layer, a stain, and a poorly adhered copper layer.

Example 2-1 Example 2-2 Example 2-3 Examples 2-4 Example 2-5 Examples 2-6 Comparative Example 2-1 Comparative Example 2-2 Spurt occurrence none none none none none none none none abnormal
Color and roughness none none none none none none Stain and poor adhesion Stain and poor adhesion

Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 Comparative Example 2-6 Comparative Example 2-7 Comparative Example 2-8 Comparative Example 2-9 Comparative Example 2-10 Spurt occurrence none has exist none has exist none none none none abnormal
Color and roughness Stain and poor adhesion none Red and rough surface none Red and rough surface Stain and poor adhesion Stain and poor adhesion Stain and poor adhesion

Evaluation Example 2 (Copper layer adhesion test)

The adhesion between the copper layer and the aluminum layer was tested on the copper-clad laminated sheet formed by the examples and comparative examples. Adhesion tests were carried out in cross-cut tests using adhesive tapes with different adhesive strengths. Adhesive tapes include Japan Ichiban (700 gf / cm), 3M 602 (400 gf / cm), 3M Scotch Cat. 122 (200 gf / cm) was used. After plating, a sheath was made on the surface of the copper foil, and the adhesive tape was attached to the cut surface and then detached at an angle of 90 degrees.

Example 2-1 Example 2-2 Example 2-3 Examples 2-4 Example 2-5 Examples 2-6 Comparative Example 2-1 Comparative Example 2-2 Adhesion 700gf / cm
More than 700gf / cm
More than 700gf / cm
More than 700gf / cm
More than 700gf / cm
More than 700gf / cm
More than 200 gf / cm
Below 200 gf / cm
Below

Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 Comparative Example 2-6 Comparative Example 2-7 Comparative Example 2-8 Comparative Example 2-9 Comparative Example 2-10 Adhesion 200 gf / cm
Below 200 gf / cm
Below 400 ~
700 gf / cm 200 gf / cm
Below 400 ~
700 gf / cm 200 ~
400 gf / cm 200 ~
400 gf / cm 200 ~
400 gf / cm

Evaluation Example 3 (Heat resistance test of the copper-clad laminated sheet)

Also, since the formed copper foil layer should not undergo interface separation between aluminum and the copper foil layer when used at a high temperature, the heat resistance test was conducted on the copper foil laminated sheet formed by the examples and the comparative examples. In the heat resistance test, the sample plated on the molten lead bath at a temperature of 260 ° C or higher was floated for about 10 to 60 seconds, and then removed to confirm whether bubbles or copper foil layer were separated from the plating surface.

Example 2-1 Example 2-2 Example 2-3 Examples 2-4 Example 2-5 Examples 2-6 Comparative Example 2-1 Comparative Example 2-2 result More than
none More than
none More than
none More than
none More than
none More than
none bubble
Occur bubble
Occur

Comparative Example 2-3 Comparative Example 2-4 Comparative Example 2-5 Comparative Example 2-6 Comparative Example 2-7 Comparative Example 2-8 Comparative Example 2-9 Comparative Example 2-10 result bubble
Occur Copper foil
Breakaway More than
none bubble
Occur More than
none Copper foil
Breakaway Copper foil
Breakaway Copper foil
Breakaway

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, . Therefore, the embodiments described in the present invention are not intended to limit the scope of the present invention but to limit the scope of the present invention. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

Claims (6)

Providing an aluminum sheet;
immersing the aluminum sheet in a strong alkaline solution having a pH of 8.5 to 10.5 to remove an oxide film formed on the surface of the aluminum sheet; And
and dipping the aluminum sheet from which the oxide film has been removed in a replacement copper plating solution having a pH of 9.5 to 12.5 to form a copper foil layer,
Wherein the pH of the replacement copper plating solution is equal to or greater than the pH of the strong alkaline solution. The method according to claim 1,
Wherein the step of removing the oxide film is performed using a strong alkaline solution having a pH of 9 to 10. delete The method according to claim 1,
Further comprising the step of attaching a polymeric resin carrier to an opposite surface of the aluminum sheet on which the copper foil layer is formed by using an adhesive. The method according to claim 1,
Wherein the step of forming the copper foil layer is performed using a replacement copper plating solution having a pH of 10 to 12. 6. A process for the preparation of a compound of formula I according to claim 1, 2, 4 and 5,
Polymer resin carriers; A pressure-sensitive adhesive layer formed on the polymeric resin carrier; An aluminum sheet attached on the pressure-sensitive adhesive layer; And a copper foil layer formed on the aluminum sheet by a substitutional copper plating method,
Wherein the adhesive sheet has an adhesive strength of 700 gf / cm or more and a heat resistance (260 DEG C) as measured by a cross-cut test using the aluminum sheet and the copper foil interlaminar adhesive tape.

Images