KR101152766B1 - Flexible thin material comprising tin-plated layer and the method of manufacturing the same - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel flexible thin film material that can be used as a material for an electronic component, and more particularly to a flexible thin film material including a tin plating layer, and more particularly, to a copper foil or a flexible copper clad laminate (FCCL) including a tin plating layer. Flexible thin film material having a tin plating layer according to the present invention can be used as a material of various electronic components having an electromagnetic shielding function, including an electrically conductive gasket, soldering is possible due to the tin plating layer, and thus automated surface mounting technology Through the application of the has the advantage of lowering the manufacturing cost.

Description

Flexible thin material comprising tin-plated layer and the method of manufacturing the same

The present invention relates to a flexible thin film material including a tin plated layer and a method for manufacturing the same, and more particularly, to a copper foil or a flexible copper foil laminated plate including a tin plated layer.

In response to the development of the electronic communication industry and the establishment of the information society, modern home appliances, industrial electronic devices and information communication devices are required to be downsized, have high processing capacity, and have low power consumption. More devices were installed in the space. As a result, it was gradually placed in an environment susceptible to electromagnetic noise and heat, and various measures were taken to solve the problem.

The main parts of the device to which electromagnetic waves leak and penetrate include a connection part of the device, a cable, a transparent display panel, and a connector connection part. The electromagnetic shielding at the connection part of the device is mainly performed to prevent outside radio waves from entering the inside of the device through the atmosphere or to prevent leakage of the electromagnetic waves generated inside the device to the outside. In order to maximize the shielding of the electromagnetic wave at the connection part of the device, it is optimal to design it seamlessly, but it is impossible to make it seamless at the connection part of the device. Therefore, electromagnetic intrusion or leakage at the connection part of the device is inevitable and an electrically conductive gasket is used to prevent it.

The conductive gasket eliminates gaps in which electromagnetic waves are emitted and introduced into and out of electronic devices, guarantees continuity of electron flow, and maintains the same potential difference. It also performs cushions to protect components in electronics.

On the other hand, conductive gaskets include finger gaskets made of beryllium or copper, conductive silicon gaskets made by mixing and curing metal powders with non-conductive silicon, and knitting gaskets knitted with conductive wires on non-conductive urethane or silicon. (knitting gasket). In addition, an electrically conductive fiber gasket in which an electrically conductive fiber is wrapped in a non-conductive urethane sponge is most commonly used. In the manufacturing method of the electrically conductive fiber gasket, electroless plating of nickel, copper, silver or gold on woven nylon or polyester fiber is used to produce the electrically conductive fiber, and the non-conductive polymer hot melt is coated on one side of the electrically conductive fiber. After applying urethane sponge while applying heat, the hot melt melts and is in contact with the urethane sponge.

However, all conventional electrically conductive gaskets have a disadvantage in that it is difficult to apply auto surface mount tecahnology (auto SMT) and thus has to resort to manual labor. Due to the inability to apply automation techniques, conventional electroconductive gaskets have a limitation in that their manufacturing costs are high. In addition, the conductive fiber gasket adopts a pressure sensitive adhesive (PSA) adhesive, which provides high electrical contact resistance, low adhesive strength, and thermal susceptibility. And most of all, the use of adhesives makes the working environment unenvironmentally friendly. Finger gasket has good electrical conductivity and adhesive strength, but has a limit of small contact area without poor elasticity. In addition, the conductive silicon gasket has a good elasticity and contact area, but has a disadvantage of poor conductivity and adhesive strength.

Accordingly, there has been a demand for the development of a new electrically conductive gasket capable of applying automated surface mounting technology and having good conductivity, adhesive strength, contact area, and elasticity.

Meanwhile, flexible copper clad laminates (FCCLs) have been used as materials for printed circuit boards (PCBs). Printed Circuit Board (PCB) is a type of electronic component formed by forming a good conductor of electricity (Copper-Copper) on an insulator. Active or Passive Component and sound or image It is a Structural Component that is in charge of interconnection and localization so that devices can perform its functions, and printed circuit boards are rigid printed circuit boards, flexible printed circuit boards (FPCB) and special Classified as a substrate. In particular, flexible printed circuit boards (FPCBs) are electronic components for overcoming the weaknesses of conventional printed circuit boards (PCBs) to cope with the trend of miniaturization and complexity of electronic products. Looking at the advantages of the flexible printed circuit board, if the moving part of the existing cable has a weakness of the cable is weak due to the weakness, but the flexible printed circuit board is a flexible, it can be used in the curved part.

The material used for such a flexible printed circuit board is a flexible copper clad laminate. The flexible copper clad laminate refers to a film-type material that is electrically conductive by selectively coating copper on a surface of a film that can be bent or bent due to its thin thickness.

In general, an adhesive is required because copper foil, which is a metal, and polyimide, which is an organic polymer, is not bonded. The flexible copper clad laminate with adhesive is called three-layer (PI, adhesive, copper foil) FCCL, and the product without adhesive is called two-layer (PI, copper foil) FCCL. Two-layer FCCL is difficult to manufacture because it does not use adhesives, but has good characteristics such as heat resistance, chemical resistance, ion transfer properties, and bendability. The two-layer FCCL is classified into three methods, a casting method, a lamination method, and a sputtering method, depending on the manufacturing method, each having advantages and disadvantages. The casting method is a method of forming a polyimide on a copper foil. It is a method of precisely coating liquid PAA (Polymic acid), which is a polyimide precursor, on copper foil and curing at high temperature to form PI, which can increase the production speed and has high adhesive strength between copper foil and polyimide. There is a limit to making the thickness of the copper foil thin. The lamination method is a coating of an adhesive thermoplastic polyimide (TPI; thermoplastic polyimide) on a commercially available polyimide film, followed by lamination by copper foil and thermocompression bonding. The two-layer FCCL produced by this method has the advantage that the productivity and copper foil-polyimide adhesion are inferior to the casting method, but the thickness of the copper foil can be made somewhat thin. The sputtering method is to plate copper on a commercially available polyimide film, which is also called a metalizing method by sputtering a seed layer to impart adhesive force before plating. This method has an advantage of thinning the thickness of the copper. However, the product by this method has a problem of low production speed and low adhesion between polyimide and copper foil.

The present invention starts with the idea that a flexible copper clad laminate can be used as a new flexible thin film material that can solve the disadvantages of existing electrically conductive gasket materials.

The present invention has begun to develop a new material that can solve all of the limitations of the materials of conventional electrically conductive gaskets. In other words, the development of new flexible thin film materials with good electrical conductivity, high adhesive strength, large contact area, and high elasticity, which are the characteristics that an electrically conductive gasket should have while reducing manufacturing costs by applying automated surface mounting technology. The present invention is a problem to be solved.

Accordingly, the present invention is to provide a novel flexible thin film material that can be applied to the automated surface mounting technology using a flexible copper clad laminate (FCCL) or copper foil which is widely used as a material of a printed circuit board (PCB). .

Furthermore, the present invention seeks to provide an effective method for producing such a novel flexible thin film material.

The present invention is to provide a new flexible thin film material in which a tin layer is plated on a flexible thin film material such as a conventional flexible copper clad laminate (FCCL) or copper foil as the new flexible thin film material. Soldering is indispensable to apply automated surface mount technology using copper foil or flexible copper clad laminate, and it is necessary to include tin layer to enable soldering on copper foil or copper foil of flexible copper clad laminate. .

By using a conventional flexible copper clad laminate or a new flexible thin film plated with a tin layer on a copper foil in an electronic component material such as an electroconductive gasket, an automated surface mounting technology can be applied, thereby lowering manufacturing costs. In addition, the use of a flexible material such as copper foil or flexible copper clad laminate enables easy deformation as desired and provides high elasticity, which is a requirement of the electrically conductive gasket. On the other hand, it is possible to provide excellent electrical conductivity by using a metal material called copper.

The present invention further provides a method for producing the new flexible thin film material.

The new flexible thin film material plated with tin on the copper foil or the flexible copper clad laminate according to the present invention can be produced by plating tin on the copper foil or the flexible copper clad laminate.

The flexible copper clad laminate may be purchased by using an already manufactured product, or may be manufactured and used according to a known method. The flexible copper clad laminate can be produced by a lamination method, a casting method, or a sputtering method.

Tin-plated copper foil or flexible copper foil laminated plate, which is a new flexible thin film material manufactured according to the present invention, can be used as a material for various electronic components having an electromagnetic shielding function including an electrically conductive gasket. In particular, when used as a material of the electrically conductive gasket, unlike the conventional material, it is possible to apply the automated surface mounting technology, there is a great advantage that can lower the manufacturing cost. In addition, by using a metal thin film of copper has a high electrical conductivity and electromagnetic shielding effect.

1 illustrates a novel flexible thin film material according to the present invention, the left side of which is a material comprising a tin plated layer on a flexible copper clad laminate, and the right side which relates to a material comprising a tin plated layer on a copper foil.

Hereinafter, the present invention will be described in detail.

The novel flexible thin film material according to the present invention has a structure as shown in FIG. That is, the new flexible thin film material according to the present invention has a structure of a copper foil or a flexible copper foil laminated plate including a tin plating layer.

The novel flexible thin film material according to the present invention has a structure in which tin is plated on the copper foil while the copper foil or the flexible copper clad laminate is the base material. On the other hand, flexible copper clad laminates can use all the flexible copper clad laminates currently developed. Both two layers of flexible copper foil laminated sheets composed of a polymer film and copper foil and three layers of flexible copper foil laminated sheets in which a polymer film and copper foil are bonded with an adhesive are possible. The polymer film of the flexible copper clad laminate includes a polyester film, a polycarbonate film, a polyimide film, a liquid crystal polymer film, a fluororesin film, and the like, and a polyimide film excellent in heat resistance, dimensional stability, and solderability is preferable.

There is no restriction | limiting in particular in the thickness of copper foil or a flexible copper foil laminated board, It is possible to change the thickness as needed.

However, in the method of plating tin, in order to use a continuous manufacturing method by a roll-to-roll method, the thickness of the copper foil or the flexible copper clad laminate is preferably 300 μm or less. If it is more than this, plating operation using a roll-to-roll apparatus is difficult. On the other hand, there is no particular limitation on the lower limit, but also considering the work in roll-to-roll equipment, there is a difficult point if the work is less than 5 ㎛. However, in the plating of the barrel method, not the plating using the roll-to-roll equipment, this restriction is not followed.

The manufacturing method of the copper foil or flexible copper foil laminated board containing the said tin plating layer is as follows. It is possible to manufacture by plating tin on the copper foil of the prepared copper foil or flexible copper foil laminated board, Preferably it can manufacture by electrolytic or electroless plating.

The plating method of tin can use all known tin plating methods. Electroplating, electroless plating, hot dip plating or vapor deposition or sputtering can be used. As the electroplating, it is possible to use a method such as sulfate bath plating or borosilicate bath plating. Various methods such as a barrel method or a roll-to-roll apparatus for electrolytic or electroless plating may be used.

Hereinafter, the present invention will be described in detail a manufacturing method of a new flexible thin film material including the tin plating layer according to the present invention by using an electrolytic plating method as a plating method of tin.

The composition for electrolytic plating of tin used in the method of the present invention includes a tin compound, an acid, a brightener and a leveler.

The tin compound useful in the present invention may be a tin compound dissolved in a solution. Suitable tin compounds are tin aryl sulfonates such as tin halides, tin sulfates, tin methane sulfonates, tin ethane sulfonates and tin propane sulfonates, tin aryl sulfonates such as tin phenyl sulfonates and tin toluene sulfonates, tin alkanols Sulfonates and the like, but are not limited thereto. It is preferred that the tin compound is tin sulfate, tin chloride, tin alkane sulfonate or tin aryl sulfonate, more preferably tin sulfate or tin methane sulfonate.

Suitable tin alkanesulfonates include tin methanesulfonate, tin ethanesulfonate and tin propanesulfonate. Suitable tin aryl sulfonates include tin phenylsulfonate and tin toluenesulfonate. Tin compounds useful in the present invention are generally commercially available from a variety of sources and can be used without further purification. In addition, tin compounds useful in the present invention can be prepared by methods known in the literature.

The amount of tin compound useful in the composition used in the method of the present invention is not particularly limited, but usually includes tin salt at a concentration of 6 to 22 g / L on a tin basis.

However, it does not need to be specifically limited to the said range.

Acids useful in the present invention can be advantageously used in the present invention with any acid dissolved in solution that does not otherwise adversely affect the electrolyte composition. Suitable acids include alkanesulfonic acids such as methane sulfonic acid, ethane sulfonic acid and propane sulfonic acid, aryl sulfonic acids such as phenyl sulfonic acid or toluene sulfonic acid, sulfuric acid, sulfamic acid, hydrochloric acid, hydrobromic acid and fluorobo Lic acid is included, but is not limited to these. The acid included in the composition used in the method of the present invention may use not only one type of single acid but also a mixture of acids. Acids useful in the present invention are generally commercially available and can be used without further purification. In addition, acids can be prepared by methods known in the literature.

Typically, the amount of acid can be appropriately selected and used in the range of 100 to 250 g / L. On the other hand, the acid used in the present invention preferably corresponds to a tin compound. That is, it is preferable to use an acid containing the same anion as that of the tin compound. For example, when tin sulfate is selected as the tin compound, the acid is preferably sulfuric acid.

Brighteners included in the compositions used in the methods of the present invention are generally capable of using any brightener that can be used to impart the brightness to tin. Aldehyde compounds, pyridine, quinoline, anisole or naphthol can be used. With an aldehyde-based compound is an aliphatic aldehyde or aromatic aldehyde compound such as acetaldehyde (acetaldehyde) or glutaraldehyde (glutaldehyde), examples of the aromatic aldehyde compound is o - methoxy benzaldehyde (o -methoxybenzaldehyde), o - chloro-benzamide Aldehyde ( o- chlorobenzaldehyde) and the like can be used.

Preferably, an aromatic aldehyde compound can be used. In the present invention, the brightening agent includes at least one compound, and it is also possible to use a commercially available brightening agent.

The amount of the brightener included in the composition used in the method of the present invention can be appropriately adjusted by those skilled in the art, for example, but may be selected from the range of 0.1 to 50 g / L, but is not necessarily limited thereto.

The leveler included in the composition used in the method of the present invention is characterized in that it contains at least one surfactant of any kind. The leveler is called a wetting agent or additive. The leveler's role in the plating solution is to increase the electrolyte's throwing power to help efficient plating, and to adjust the current density accordingly. It also plays a role of affecting the plating thickness by controlling the amount of metal deposited on the plated body.

As the surfactant, it is possible to use a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant or a mixture of any two or more thereof. With regard to surfactants it is possible to use all generally known surfactants.

Anionic surfactants are those which dissociate ions in aqueous solution and exhibit anionic activity, and can be broadly classified into carboxylates, sulfonates, sulfate ester salts, and phosphate ester salts. Carboxylic acid salts include higher fatty acid alkali salts, N-acrylic amino acid salts, alkyl ether carbonates, and acylated peptides. Sulfonate salts include alkylsulfonic acid salts, alkylbenzenes and alkylamino acid salts, alkylnaphthalene sulfonate salts, and sulfobacterite salts. The sulfur ester salts include sulfated oil, alkyl sulfates, alkyl ether sulfates, alkylaryl ether sulfates, and alkylamide sulfates, and phosphate ester salts include alkyl phosphates, alkyl ether phosphates, and alkylaryl ether phosphates.

Unlike the anionic surfactants, cationic surfactants are cations having a surface activity, and examples of the hydrophilic group include primary to tertiary amine salts or quaternary ammonium salts, phosphonium salts, and sulfonium salts. On the other hand, there may be an aliphatic or aromatic hydrocarbon as a hydrophobic group.

Amphiphilic surfactants are surfactants having both a cationic functional group and an anionic functional group in one molecule at the same time, and are categorized according to the type of anionic functional group of the hydrophilic group, or betaine based, imidazoline based, or β- depending on chemical structure. It may be divided into alanine and amino.

On the other hand, there are some nonionic surfactants which do not have ions in the molecular structure, and they can be broadly divided into ether type, ester ether type and ester type nitrogen-containing type. The ether type includes polyalkylene glycol, a copolymer of ethylene oxide and propylene oxide, and the ester ether type includes polyoxyethylene ether of glycerin ester, polyoxyethylene ether of sorbitan ester, polyoxyethylene ether of sorbitol ester, and the like. The ester type includes polyethylene glycol fatty acid ester, glycerin ester, sorbitan ester, propylene glycol ester, and sugar ester. The nitrogen-containing types include fatty acid alkanolamide, polyoxyethylene fatty acid amide, polyoxyethylene alkylamine, and amine. Oxides and the like.

Usually, it is possible to use a leveler containing at least one kind of all kinds of surfactants used in the electrolytic or electroless plating method of tin, and it is preferable to use a nonionic surfactant. Polyalkylene glycols such as glycol, flopropylene glycol, or copolymers of ethylene oxide and propylene oxide (EO / PO copolymer), and nonylphenol. In addition, it is also possible to mix and use the said nonionic surfactant in a fixed ratio. In general, polyalkylene glycols used as levelers may be used having an average molecular weight of about 200 to about 100,000, but is not necessarily limited thereto.

On the other hand, in the present invention, the concentration of the leveler can be appropriately selected by those skilled in the art, for example, it can be selected in the range of 0.5 to 100 g / L, but is not necessarily limited thereto.

Meanwhile, the composition for tin plating used in the method of the present invention may further include any other additives in addition to the tin compound, acid, brightener, and leveler, for example, tin divalent ions are oxidized to tetravalent ions. There may be an antioxidant and the like to prevent. Antioxidants include hydroquinone, catechol, resorcin, phloroglucin, pyrogallol, hydroquinonesulfonic acid, and salts thereof. If desired, other commonly known additives, such as plating uniformity improvers, glossing agents, smoothing agents, conductive agents, and anode dissolving agents, may be added in the compositions of the present invention. Can be. In the barrel plating method, an anti-sticking agent and / or acrylic acid or an acrylic acid derivative for preventing adhesion of the substrates may be further included.

The order in which the various components are added when making the composition is not particularly limited, but from the standpoint of safety, the acid is added after the water is added, after sufficient mixing, after the tin salt is added, after sufficient mixing, The required chemicals are added in order.

In the above, the composition used for the tin plating method which concerns on this invention was demonstrated.

Next, the conditions in the electroplating process of tin are demonstrated.

The electroplating process of tin can select and use methods, such as a barrel system and a roll-to-roll system, as needed. However, the present invention will be described on the premise of the roll-to-roll method.

The current density for the electroplating is used in the conventional conditions, specifically, the electroplating may be carried out in the current density conditions in the range of 0.5 ~ 20 A / dm ² . However, it is not necessarily limited to the above range.

In addition, in the tin electroplating method according to the present invention, the temperature is not particularly limited, but is selected in the range of 10 to 50 ° C., preferably 15 to 30 ° C., and the inside of the plating bath may not be stirred, but preferably do.

Hereinafter, the present invention will be described in detail using examples. However, the present embodiment is only present one example for implementation so that the invention is easy to understand, the present invention is not limited to the specific scope of the embodiment.

Tin plating in this invention was performed using the roll-to-roll apparatus for tin on copper foil using the flexible copper foil laminated board or copper foil as a board | substrate.

Flexible copper clad laminates can be used by purchasing commercial products. However, in the present invention, a semi-finished product laminated by sputtering a copper seed layer on a polyimide (product width 300 mm, polyimide film is DuPont Kapton 150E thickness 25 ㎛, copper seed layer thickness 4000 Å; or less' Semi-finished product 1 ') was purchased and prepared by electroplating copper in a conventional manner to a thickness of 3.5 탆 on this copper layer. It is obvious that electroless plating is also possible. Meanwhile, as the other semi-finished product, the remainder is the same, and a semi-finished product in which Ni-Cr (9: 1) is laminated by a sputtering method to a thickness of 200 kPa for higher peel strength between the copper seed layer and the polyimide film. ('Semi-finished product 2').

On the other hand, copper foil was used for the Example of a product having a thickness of 30 ㎛ produced in yigu industry.

The electroplating conditions of copper are as follows.

Pentahydrate of copper sulfate _{(CuSO 4? 5H 2 O)} 90 g / L, sulfuric acid 180 g / L, polisher (Uyemura's ETN-1-A) 1.0 g / L, leveler (Uyemura's ETN-1-B) 10 g A copper electrolytic plating solution containing / L was prepared, the plating time was 4 minutes, the current was 162 amps, the temperature of the plating solution was 25 ° C., the current density was 0.8 A / dm ² , and the anode was soluble ball type with purity of 99.9% or more. Two types of flexible copper clad laminates were prepared by electroplating a copper layer having a thickness of 3.5 μm using Cu metal.

Conduct electroplating of tin on flexible copper clad laminates:

Electroplating of tin was carried out using the flexible copper clad laminated board prepared using the semi-finished product 1.

The electroplating composition of tin was electroplated with 33 g / L of tin sulfate (14.7 g / L based on tin), 180 g / L of sulfuric acid, and 10 g / L of leveler at a concentration of 3 g / L. . Of course, the rest in the composition was filled with distilled water. The polisher and leveler were purchased from commercially available products, and T-LSB-A and T-LSB-B manufactured by Extol Inc. in Korea were used as the polisher and leveler. T-LSB-A includes an aromatic aldehyde compound. T-LSB-B comprises a mixture of PEG-600 and an EO / PO copolymer.

On the other hand, the current density when performing the electroplating was adjusted to be maintained in the 0.5 ~ 3 A / dm ² range. The plating time was 1 minute 40 seconds, the plating thickness was fixed at about 2.5 μm, the solution temperature in the plating bath was 25 ° C., and 99.99% pure soluble solid tin was used as the anode. The current applied 60 amps. In order to prevent contamination of the plating solution, the filter was continuously filtered using a filter having a 1 μm gap, and in order to solve the nonuniformity of the plating thickness which may be caused by the large increase in the amount of current at the edge due to the throwing effect of the current. The shield is used widely, and it is fixed to cover the 20mm width of the product.

In the meantime, the following experiment was conducted to confirm whether the tin-plated flexible copper clad laminate had proper solderability.

Solderability Test

The solderability test of the tin plated layer was applied to the internationally widely used method of JEDEC SPEC EIA / JDEC 22-B102-C, among which precondition was applied for 8 hours of steam aging as specified in condition C. The criterion of acceptance and failure in the solderability test is determined to be successful when more than 95% of the solder is applied based on the surface area of the tested product, and to be less than that.

Solderability test results were successful.

Conduct electroplating of tin on flexible copper clad laminate using semi-finished product 2:

Tin was plated on copper in the same manner as in Example 1 except that the concentration of the polish was 3.0 g / L and the leveler was fixed at 10 g / L. The solderability test was successful.

Conduct electroplating of tin on copper foil:

Electrolytic plating was performed by the roll-to-roll method using the copper foil of thickness 30micrometer thick. The conditions were the same as in Example 2, and the solderability test result was successful.

Claims (8)

delete delete As a flexible thin film material for an electronic component material, which comprises a tin plating layer on a copper foil or a flexible copper foil laminated plate,
The flexible thin film material is copper foil or flexible copper clad lamicate (FCCL),
The electronic component is a flexible thin film material, characterized in that it has an electromagnetic shielding function.
delete The flexible thin film material according to claim 3, wherein the flexible copper clad laminate is plated with electrolytic or electroless plating on a polyimide film.
4. The flexible thin film material according to claim 3, wherein the flexible copper clad laminate has copper laminated on a polyimide film by a sputtering method and copper is electrolytically or electroless plated on the seed layer.
The method of claim 3, wherein the flexible copper clad laminate is a primary seed layer of Ni-Cr on the polyimide film and a secondary seed layer of copper on the primary seed layer by a sputtering method and copper is electrolytically or electrolessly deposited thereon. Flexible thin film material, characterized in that the plated.
The flexible thin film material of claim 3, wherein the tin plating layer has solderability in which solder is applied to at least 95% of the surface area during the solderability test.

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