KR20240036699A - Manufacturing method of composite material to be plated and manufacturing method of anisotropic conductive sheet - Google Patents

Abstract

The object is to provide a method for manufacturing a composite material to be plated that is capable of forming a plating layer with good adhesion to a plurality of resin parts each containing different resins. A method of manufacturing a composite material to be plated that solves the above problem includes a process of preparing a composite material having a heat-resistant resin portion containing a heat-resistant resin and a silicone resin portion containing a silicone resin, and plating the plated area of the composite with an alkaline solution. A step of treating, a step of irradiating plasma to the plated area treated with the alkaline solution, a step of contacting the plated area irradiated with the plasma with a cationic catalyst-containing liquid, and applying the catalyst-containing liquid to the plated area treated with the alkaline solution. A step of performing an electroless plating treatment on the contacted area to be plated, wherein the area to be plated includes at least a part of the heat-resistant resin part and at least a part of the silicone resin part.

Description

Manufacturing method of composite material to be plated and manufacturing method of anisotropic conductive sheet

The present invention relates to a manufacturing method of a composite material to be plated and a manufacturing method of an anisotropic conductive sheet.

Conventionally, a plating layer is formed on an insulating substrate made of resin or the like for the purpose of providing conductivity of electromagnetic waves or electricity, imparting heat conductivity, or improving the design of the product. As a method of forming a plating layer on the surface of an insulating substrate, sputter plating methods and the like are known. In this method, a metal layer is formed on the surface of an insulating substrate by a sputtering method, and then electrolytic plating is performed. Therefore, an expensive sputtering device is required, and there are problems in terms of productivity and the like.

On the other hand, as a method of forming a plating layer, an electroless plating method is also known. According to the electroless plating method, a metal plating layer can be efficiently formed on the surface of an insulating substrate. However, depending on the type of insulating substrate, adhesion to the plating layer may be low. Therefore, in Patent Document 1, it is proposed to improve the adhesion of the plating layer by treating the surface of the insulating substrate with an alkaline solution before forming the plating layer. Additionally, in Patent Document 2, it is proposed to improve the adhesion of the plating layer by treating with an alkaline solution and then further treating with an aqueous amino acid solution or the like.

Japanese Patent Publication No. 2021-5624 Japanese Patent Publication No. 2007-56343

According to the method of Patent Document 1 or Patent Document 2, it is possible to increase the adhesion between an insulating base material containing a single resin and a plating layer. However, in composite materials made by laminating multiple resin layers containing different resins, or composite materials made by combining multiple parts containing different resins, the adhesion to the plating layer is different for each resin. Therefore, there were problems such as the plating layer not adhering to some areas (resin), or even if the plating layer could be formed, it would peel off when stress was applied to the composite material. In addition, especially when the composite material contains a silicone resin, it was difficult to increase the adhesion between the area containing the silicone resin and the plating layer.

The purpose of the present invention is to provide a method for producing a composite material to be plated, and a method for producing an anisotropic conductive sheet, which can form a plating layer with good adhesion on a plurality of resin parts each containing different resins.

The present invention includes a process of preparing a composite material having a heat-resistant resin portion containing a heat-resistant resin and a silicone resin portion containing a silicone resin, a process of treating a plated area of the composite with an alkaline solution, and the alkaline solution. A process of irradiating plasma to the treated area to be plated, a process of contacting the area to be plated irradiated with the plasma with a cationic catalyst-containing liquid, and applying a radioless electrolyte to the area to be plated to which the catalyst-containing liquid has been brought into contact. A method of manufacturing a composite material to be plated is provided, including a step of performing a plating treatment, wherein the area to be plated includes at least a portion of the heat-resistant resin portion and at least a portion of the silicone resin portion.

In the present invention, a heat-resistant resin layer containing a heat-resistant resin and a silicone resin layer containing a silicone resin are laminated in the thickness direction, a first surface located on one side of the thickness direction and a second surface located on the other side. A step of preparing an insulating sheet having a through hole penetrating the surface, a step of treating the outer wall of the through hole of the insulating sheet with an alkaline solution, and a step of irradiating plasma to the outer wall treated with the alkaline solution. and a method for producing an anisotropic conductive sheet, including a step of contacting the outer wall irradiated with the plasma with a cationic catalyst-containing liquid, and a step of performing an electroless plating treatment on the outer wall brought into contact with the catalyst-containing liquid. to provide.

According to the method for producing a composite material to be plated of the present invention, it is possible to form a plating layer with good adhesion to a plurality of resin parts each containing different resins.

1A in FIG. 1 is a photograph taken with a scanning electron microscope of the surface of an untreated silicone resin portion, and FIG. 1B is a photograph taken with a scanning electron microscope of the surface of the silicone resin portion after treatment with an alkaline solution. 1C is a photograph taken with a scanning electron microscope of the surface of the silicone resin portion after the plasma irradiation process.
2A in FIG. 2 is a plan view showing an example of the structure of an anisotropic conductive sheet manufactured by the method for manufacturing an anisotropic conductive sheet of the present invention, and FIG. 2B is a partially enlarged cross-sectional view taken along the line 1B-1B in FIG. 2A.
Figure 3 is a graph showing the amount of COOH groups on the surface of the heat-resistant resin portion before contact with the catalyst-containing liquid in Examples and Comparative Examples.
Figure 4 is a graph showing the amount of Si-OH bonds on the surface of the silicone resin portion.

Hereinafter, the manufacturing method of the composite material to be plated and the manufacturing method of the anisotropic conductive sheet of the present invention will be described with specific embodiments as examples. However, the method for producing the plated composite material of the present invention is not limited to this method.

1. Manufacturing method of plated composite material

The method for producing a composite to be plated of the present invention includes a process of preparing a composite having a heat-resistant resin portion containing a heat-resistant resin and a silicone resin portion containing a silicone resin (hereinafter also referred to as “composite preparation process”), and the composite A process of treating the area to be plated with an alkaline solution (hereinafter also referred to as “alkaline solution treatment process”), and a process of irradiating plasma to the area to be plated treated with an alkaline solution (hereinafter also referred to as “plasma irradiation process”) a process of bringing a cationic catalyst-containing liquid into contact with the plated area irradiated with plasma (hereinafter also referred to as “catalyst contact process”), and an electroless plating treatment on the plated area brought into contact with the catalyst-containing liquid. A process to be performed (hereinafter also referred to as “electroless plating treatment process”) is included. Steps other than these may be included as long as the effect and purpose of the present invention are not impaired.

As described above, when a plating layer is formed on the surface of a composite material having a plurality of resin parts containing different resins, each resin part has a different adhesion to the plating layer. Therefore, there were problems such as the plating layer not adhering to some resin parts or being easily separated from parts where the adhesion to the plating layer was weak. On the other hand, in the method for producing a composite material to be plated according to the present invention, an alkaline solution treatment process and a plasma irradiation process are performed in this order on the plated area of the composite material, followed by a catalyst contact process and an electroless plating treatment process. By performing the alkaline solution treatment process and the plasma irradiation process in order, the adhesion between the area containing each resin (heat-resistant resin part and silicone resin part in the present invention) and the plating layer is significantly improved, and the adhesion of the plating layer is high in any area. , a plated composite material is obtained.

The reason is thought to be as follows. Figure 1A shows a photograph taken with a scanning electron microscope (hereinafter also referred to as “SEM photograph”) of the surface of the untreated silicone resin portion, and Fig. 1B shows an SEM photograph of the silicone resin portion after alkaline solution treatment. Figure 1C shows an SEM photograph of the silicone resin portion after the plasma irradiation process. As shown in FIG. 1A, many aggregates exist on the surface of the untreated silicone resin portion. It is thought that if such aggregates exist, when forming a plating layer, it will be difficult for the plating layer to adhere to the surface of the silicone resin portion, making it easy for the plating layer to peel off.

In contrast, when the silicone resin portion is treated with an alkaline solution, the aggregates are removed and the surface is smoothed, as shown in FIG. 1B. After that, when the silicone resin part is subjected to plasma treatment, Si-OH groups are introduced into the surface. Therefore, it is thought that it becomes easy for the plating layer to come into close contact with the silicone resin portion physically and chemically, and the adhesion to the plating layer increases. Meanwhile, in the heat-resistant resin portion as well, foreign substances are removed by an alkaline solution treatment process, or COOH groups are introduced into the surface by a plasma irradiation process. Therefore, it is thought that the adhesion to the plating layer also increases in the heat-resistant resin portion.

On the other hand, according to intensive studies by the present inventors, it was confirmed that the plating layer does not adhere sufficiently just because the amount of Si-OH groups on the surface of the silicone resin part or the amount of COOH groups on the surface of the heat-resistant resin part is large. As will be shown in detail in the examples described later, for example, if only the plasma irradiation process is performed without performing the alkaline solution treatment process, the amount of Si-OH groups and COOH groups in each region increases. However, forming a plating layer in these areas causes peeling. That is, as described above, it is thought that it is very important for the adhesion of the plating layer to sufficiently smoothen or normalize the surface of each region by the alkaline solution treatment process and then introduce Si-OH groups or COOH groups. Hereinafter, each process of the method for producing a plated composite material of the present invention will be described.

(1) Composite preparation process

In the composite preparation process, a composite material having a heat-resistant resin portion and a silicone resin portion is prepared. The shape of the composite material is not particularly limited; for example, it may be flat or have a three-dimensional shape. It is appropriately selected according to the purpose of the composite material to be plated.

Additionally, the shapes of each of the heat-resistant resin portion and the silicone resin portion are not particularly limited, and may be disposed so that a portion of the heat-resistant resin portion and a portion of the silicone resin portion are exposed to the surface of the composite material, respectively. The composite material may have a structure in which a heat-resistant resin portion and a silicone resin portion are laminated, such as an insulating sheet of an anisotropic conductive sheet described later. Additionally, the composite material may have a structure in which a member made of a heat-resistant resin part and a member made of a silicone resin part are connected or bonded. On the other hand, the composite material is a region other than the heat-resistant resin portion or the silicone resin portion, that is, a region composed of a resin other than the heat-resistant resin or silicone resin, or a region composed of a metal or ceramic, to the extent that the purpose and effect of the present invention are not impaired. etc. may be included.

The heat-resistant resin included in the heat-resistant resin portion is preferably a resin with high heat resistance, that is, a resin with a high glass transition temperature. The glass transition temperature of the heat-resistant resin is appropriately selected depending on the intended use of the composite material to be plated. When the composite material to be plated is an anisotropic conductive sheet described later, the glass transition temperature of the heat-resistant resin is preferably 150°C or higher, and more preferably 150 to 500°C. The glass transition temperature of the heat-resistant resin is measured based on JIS K 7095:2012.

In addition, the heat-resistant resin is preferably a resin that is difficult to erode by chemicals used in the alkaline solution treatment process or electroless plating treatment process described later. Examples of such heat-resistant resins include engineering plastics such as polyamide, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, and polyetherimide; Includes acrylic resin, urethane resin, epoxy resin, olefin resin, etc. The heat-resistant resin portion may contain only one type of these heat-resistant resins, or may contain two or more types. In addition, the heat-resistant resin portion may further contain other components such as fillers as needed.

On the other hand, the silicone resin contained in the silicone resin portion may be a resin containing a siloxane structure, examples of which include polydimethylsiloxane, polyphenylmethylsiloxane, polyalkylalkenylsiloxane, and polyalkylhydrosiloxane. Included. Additionally, the silicone resin may be an addition cross-linked product of a silicone-based elastomer composition containing an organopolysiloxane having a hydrosilyl group (SiH group), an organopolysiloxane having a vinyl group, and an addition reaction catalyst, or a pentapolysiloxane having a vinyl group. It may be an addition cross-linked product of a silicone rubber composition containing nopolysiloxane and an addition reaction catalyst. Furthermore, it may be a crosslinked product of a silicone-based elastomer composition containing organopolysiloxane having a SiCH ₃ group and an organic peroxide curing agent.

Examples of the addition reaction catalyst include metals, metal compounds, and metal complexes that have catalytic activity for hydrosilylation reaction, and specifically include platinum, platinum compounds, and complexes thereof. Additionally, examples of organic peroxide curing agents include benzoyl peroxide, bis-2,4-dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and the like. On the other hand, in addition to the silicone resin, the silicone resin portion may further contain components other than the silicone resin, such as a tackifier, a silane coupling agent, and a filler, as needed.

(2) Alkaline solution treatment process

In the alkaline solution treatment process, the area to be plated of the composite material is treated with an alkaline solution. In this specification, the plated area of the composite material refers to the area where the plating layer is formed by the electroless plating process described later. For example, the entire surface of the composite material may be used as a plated area, or only a portion of the area may be used as a plated area. Additionally, only one location of the composite material may be used as a plated area, or a plurality of areas may be used as a plated area. On the other hand, any portion of the area to be plated may include at least a portion of the heat-resistant resin portion and at least a portion of the silicone resin portion. For example, the region to be plated may be a combination of a region composed only of a heat-resistant resin portion and a region composed only of a silicone resin portion. However, it is more preferable that one area to be plated includes both the heat-resistant resin portion and the silicone resin portion. In the conventional method, when a plating layer was formed on a region containing both the heat-resistant resin portion and the silicone resin portion, peeling of the plating layer was particularly likely to occur. On the other hand, according to the method of the present invention, a plating layer with good adhesion can be formed even on such areas.

The method of treating the area to be plated with an alkaline solution is not particularly limited. Although only the area to be plated may be brought into contact with the alkaline solution, it is preferable from the viewpoint of manufacturing efficiency, etc. to immerse the composite material in the alkaline solution and bring the entire composite material into contact with the alkaline solution.

The type of alkaline solution is not limited as long as it is possible to adjust the surface condition of the area to be plated or remove foreign substances adhering to the surface of the area to be plated. Examples of alkaline solutions include aqueous sodium hydroxide solution, potassium hydroxide solution, and lithium hydroxide. Among these, aqueous sodium hydroxide solution is preferable.

Additionally, the pH of the alkaline solution is more preferably 12 or higher. Also, for example, when using sodium hydroxide or potassium hydroxide as an alkaline solution, their concentration is preferably about 1 to 100 g/L, and more preferably 5 to 50 g/L. If the concentration of the alkaline solution is within this range, the area to be plated can be treated to a desired surface condition without deteriorating the composite material.

The temperature of the alkaline solution when brought into contact with the composite material is preferably 20°C to 90°C, and more preferably 40°C to 70°C. If the temperature of the alkaline solution is within this range, the surface of the area to be plated can be treated efficiently.

Furthermore, the contact time between the composite material and the alkaline solution is preferably about 10 to 50 minutes, and more preferably about 15 to 40 minutes. Within this range, the area to be plated can be sufficiently treated. On the other hand, it is difficult to deteriorate the composite material, and the composite material to be plated can be manufactured efficiently.

Additionally, when contacting the plated area of the composite with an alkaline solution, ultrasonic treatment may be performed simultaneously. If ultrasonic treatment is performed simultaneously, foreign substances, etc. attached to the surface of the area to be plated can be efficiently removed. Additionally, when the area to be plated is a through hole or recess provided in the composite material, an alkaline solution can be allowed to enter the area to be plated. The conditions for ultrasonic treatment are not particularly limited, and can be, for example, a frequency of 20 to 60 kHz.

After treatment with the alkaline solution, the alkaline solution adhering to the composite material may be neutralized with an acid solution. The neutralization method is not particularly limited, and examples include applying an acid solution to a desired area or immersing the entire composite material in an acid solution. Specific examples of acid solutions used for neutralization include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as acetic acid, methanesulfonic acid, and sulfamic acid. Among these, sulfuric acid or hydrochloric acid is preferable from the viewpoints of handling, ease of availability, cost, etc. The pH and type of the acid solution are appropriately selected depending on the pH and type of the alkaline solution.

The temperature of the acid solution when brought into contact with the composite material is preferably 10°C to 70°C, and more preferably 20°C to 60°C. If the temperature of the acid solution is within this range, the surface of the area to be plated can be treated efficiently.

Furthermore, the contact time between the composite material and the acid solution is preferably about 10 seconds to 10 minutes, and more preferably about 30 seconds to 5 minutes. Within this range, the area to be plated can be sufficiently treated. On the other hand, it is difficult to deteriorate the composite material, and the composite material to be plated can be manufactured efficiently.

Additionally, ultrasonic treatment may be performed when the composite material is brought into contact with an acid solution. If ultrasonic treatment is performed simultaneously, when the area to be plated is a through hole or recess provided in the composite material, a sufficient amount of the acid solution can be allowed to enter the area to be plated. The conditions for ultrasonic treatment are not particularly limited and can be performed in the same manner as in the case of treatment with an alkaline solution.

(3) Plasma irradiation process

In the plasma irradiation process, plasma is irradiated to the area to be plated after the alkaline solution treatment process. Plasma irradiation may be performed on the composite material from only one direction or from multiple directions. For example, plasma irradiation may be performed on a sheet-like composite material from both the front and back sides. Additionally, plasma irradiation may be performed only on the plating area, or the entire composite material may be irradiated.

The plasma irradiation method is not particularly limited, and may be a known plasma irradiation method, for example, normal pressure plasma irradiation or vacuum plasma irradiation (low-temperature plasma irradiation).

In atmospheric pressure plasma irradiation, discharge treatment is performed in a gas atmosphere containing one or two or more types of air, water vapor, argon, nitrogen, helium, carbon dioxide, carbon monoxide, alcohols such as isopropyl alcohol, and carboxylic acids such as acrylic acid. do it

In vacuum plasma irradiation (low-temperature plasma irradiation), for example, the above-mentioned composite material is placed in an internal electrode type discharge processing device having a drum-shaped electrode and a counter electrode made of a plurality of rod-shaped electrodes. Then, the pressure inside the device is preferably set to about 1 to 20 Pa, more preferably 10 Pa or less, and a high voltage of direct current or alternating current is applied between the electrodes in a process gas atmosphere to cause discharge. As a result, a plasma of the processing gas is generated, and the composite material is processed by the plasma.

For example, argon, nitrogen, helium, carbon dioxide, carbon monoxide, air, water vapor, alcohols such as isopropyl alcohol, carboxylic acids such as acrylic acid, etc. can be used alone or in a mixture of two or more types. there is.

Among the above plasma irradiations, vacuum plasma irradiation is preferable, and oxygen plasma irradiation using a gas containing oxygen as a processing gas is particularly preferable. When oxygen plasma is irradiated, COOH groups can be efficiently introduced to the surface of the region containing the heat-resistant resin layer, and further, Si-OH groups can be efficiently introduced to the surface of the silicone resin portion.

The oxygen supply amount is preferably 5 to 40 ml/min, and more preferably 10 to 30 ml/min.

In addition, the high-frequency output during plasma irradiation is not particularly limited, but for example, when the processing time is about 1 minute, the high-frequency output is preferably 75 to 150 W, and more preferably 90 to 125 W. If the output during plasma irradiation is 75 W or more, sufficient plasma can be generated and efficient processing can be achieved. On the other hand, if the output is 150W or less, the composite material can be processed without deteriorating it.

The plasma irradiation time is preferably 0.1 to 5 minutes, and more preferably 0.5 to 2 minutes. When plasma irradiation is performed for 0.5 minutes or more, COOH groups can be introduced into the surface of the region containing the heat-resistant resin layer, or Si-OH groups can be introduced into the surface of the silicone resin portion. On the other hand, if it is 2 minutes or less, treatment can be performed without causing damage to the composite material.

(4) Catalyst contact process

The catalyst contact process is a process of bringing a cationic catalyst-containing liquid into contact with the area to be plated after the plasma irradiation process.

A method of contacting the area to be plated with a cationic catalyst-containing solution can be, for example, immersed in a solution containing a cationic catalyst, but is not limited to this method. On the other hand, when only a partial area of the composite material is used as the area to be plated, masking may be performed by applying a resist or the like to prevent the catalyst from adhering to parts other than the area to be plated.

The cationic catalyst-containing liquid may be a solution containing metal ions (cations) that serve as a catalyst in the electroless plating process described later. Examples of metals that serve as catalysts include Ag, Cu, Al, Ni, Co, Fe, Pd, etc. Among these, Ag or Pd is preferable from the viewpoint of catalytic ability, and Pd is especially preferable.

Additionally, the metal is contained as a metal salt or complex in the catalyst-containing liquid. The type of metal counter ion in the metal salt or the ligand in the complex is appropriately selected depending on the type of metal.

Examples of palladium salts include palladium acetate, palladium chloride, palladium nitrate, palladium bromide, palladium carbonate, palladium sulfate, bis(benzonitrile)dichloropalladium(II), bis(acetonitrile)dichloropalladium(II), and bis. (Ethylenediamine) palladium(II) chloride, etc. are included. Among these, palladium chloride, palladium nitrate, palladium acetate, and palladium sulfate are preferable in terms of ease of handling and solubility.

Complexing agents constituting the palladium complex include basic amino acids having a cationic group (e.g., amino group or guanidyl group) such as lysine, arginine, ornithine, tetrakistriphenylphosphine, or trisbenzylideneacetone. there is.

The catalyst-containing liquid usually contains a solvent for dispersing or dissolving the metal salt or complex. The type of solvent is not particularly limited as long as it does not erode the composite material. Examples include water, acetone, methyl acetoacetate, ethyl acetoacetate, ethylene glycol diacetate, cyclohexanone, acetylacetone, acetophenone, 2-(1-cyclohexenyl), and propylene glycol diacetate. , triacetin, diethylene glycol diacetate, dioxane, N-methylpyrrolidone, dimethyl carbonate, and dimethyl cellosolve.

Additionally, the catalyst solution may contain a pH buffering agent such as boric acid or sodium borate, as long as it does not impair the effect of the present invention.

Here, the temperature of the catalyst-containing liquid when bringing the composite material into contact with the cationic catalyst-containing liquid is preferably 20 to 60°C, and more preferably 30 to 50°C. If the temperature of the catalyst-containing liquid is 20°C or higher, the metal ion can be efficiently reacted with the COOH group or Si-OH group in the area to be plated. On the other hand, if the temperature is below 60°C, it is difficult to affect the composite material.

The contact time between the composite material and the catalyst-containing liquid is preferably 0.5 to 10 minutes, and more preferably 1 to 5 minutes. If the contact time of the cationic catalyst-containing liquid is 0.5 minutes or more, the metal ion can be efficiently reacted with the COOH group or Si-OH group of the area to be plated. On the other hand, if it is less than 10 minutes, it is difficult to affect the composite material.

After introducing the metal ion to the surface of the composite material, the metal ion may be reduced. Reduction may be performed in the electroless plating process described later, but may be performed by treatment with a reducing agent (catalyst activating liquid) before performing the electroless plating process. For example, the composite material may be immersed in a solution containing a reducing agent.

Examples of reducing agents include boron-based reducing agents such as sodium borohydride, dimethylamine borane, and boric acid, formaldehyde, hypophosphorous acid, and the like.

The temperature of the reducing agent when treated with the reducing agent and the contact time between the composite material and the reducing agent are appropriately selected depending on the type of reducing agent.

(5) Electroless plating process

In the electroless plating treatment process, electroless plating treatment is performed on the area to be plated to which a metal serving as a catalyst has been deposited. In the electroless plating treatment process, the area to be plated is brought into contact with an electroless plating bath containing metal ions to be deposited as plating, and the metal is deposited on the surface of the area to be plated by a chemical reaction. The method of contacting the electroless plating bath with the area to be plated is not particularly limited. Only the area to be plated may be brought into contact with the electroless plating bath, or the entire composite material may be immersed in the electroless plating bath. On the other hand, when only a part of the composite material is used as the area to be plated, masking may be performed by applying a resist or the like to prevent the electroless plating bath from adhering to parts other than the area to be plated.

The electroless plating bath usually contains salt, reducing agent, solvent, stabilizer, etc., which serve as raw materials for the desired plating layer. Here, examples of metals constituting the plating layer include copper, tin, lead, nickel, gold, palladium, rhodium, etc., and these can be used one type or in combination of two or more types. Among these, copper or gold is preferable from the viewpoint of conductivity, such as when producing the conductive layer of an anisotropic conductive sheet described later.

Additionally, the reducing agent, solvent, and stabilizer are appropriately selected according to the type of metal. For example, when forming a plating layer made of copper, the electroless plating bath contains, for example, CuSO ₄ , a reducing agent such as HCOH, glyoxylic acid or a salt thereof, a chelating agent such as EDTA or Rochelle salt, and trimethylamine. Stabilizers such as alkanolamines, solvents such as water, ketones (acetone, etc.), alcohols (methanol, ethanol, isopropanol, etc.), 2,2'-dipyridyl disulfide, 6,6'-disulfide It may contain organic compounds such as odinicotinic acid, 2,2'-dithiodibenzoic acid, and bis(6-hydroxy-2-naphthyl) disulfide.

The temperature of the electroless plating bath when the composite material is brought into contact with the electroless plating bath is preferably 25 to 70°C, and more preferably 30 to 50°C. If the temperature of the electroless plating bath is 25°C or higher, a plating layer can be formed efficiently. On the other hand, if the temperature is 70°C or lower, it is difficult to affect the composite material.

The contact time between the composite material and the electroless plating bath is preferably 3 to 45 minutes, and more preferably 10 to 30 minutes. If the contact time of the electroless plating bath is 3 minutes or more, a plating layer can be formed efficiently. On the other hand, if it is less than 45 minutes, it is difficult to affect the composite material. As a result, a composite material to be plated in which the desired plating layer is formed in the area to be plated is obtained. On the other hand, after contact with the electroless plating bath, annealing treatment or the like may be performed as necessary. The annealing treatment is preferably heated at about 100°C to 150°C, and the treatment time is preferably 5 to 30 minutes.

2. Manufacturing method of anisotropic conductive sheet

It is also possible to manufacture an anisotropic conductive sheet according to the above-described method of manufacturing a composite material to be plated. An anisotropic conductive sheet in this specification is a sheet that has conductivity in the thickness direction and insulation in the surface direction. The anisotropic conductive sheet can be used as a probe (contactor) in electrical testing. The anisotropic conductive sheet manufactured by the method of the present invention has a heat-resistant resin layer containing a heat-resistant resin and a silicone resin layer containing a silicone resin laminated in the thickness direction, a first surface located on one side in the thickness direction, and It has an insulating sheet having a through hole penetrating the second surface located on the other side, and a conductive layer (plating layer) formed in the through hole.

The anisotropic conductive sheet is disposed between the substrate of the electrical inspection device and the inspection object in order to reliably make electrical contact between the electrodes of the substrate of the electrical inspection device and the terminals of the inspection object. And during electrical inspection, a press load is applied to ensure electrical connection between the board of the electrical inspection device and the inspection object. Therefore, the anisotropic conductive sheet is required to be easily elastically deformed in the thickness direction. Therefore, it is being considered to use an insulating sheet as a sheet in which a heat-resistant resin layer with a relatively high elastic modulus and a silicone resin layer with a low elastic modulus are laminated. However, in the prior art, it was difficult to form a plating layer with high adhesion to both the heat-resistant resin layer and the silicone resin layer. Therefore, when the conductive layer was formed by plating, the conductive layer was likely to peel off when an indentation load was applied.

On the other hand, when an anisotropic conductive sheet is manufactured according to the above-described method of manufacturing a composite material to be plated, it is possible to form a plating layer (conductive layer) with good adhesion to both the heat-resistant resin layer and the silicone resin layer, thereby providing highly reliable anisotropic conductivity. A sheet is obtained. Hereinafter, the configuration of the anisotropic conductive sheet will first be described, and then the manufacturing method will be described.

(1) Composition of anisotropic conductive sheet

2A and 2B show an example of the structure of an anisotropic conductive sheet manufactured by the anisotropic conductive sheet manufacturing method of the present invention. However, the structure of the anisotropic conductive sheet is not limited to this structure. In addition, FIG. 2A is a top view of the anisotropic conductive sheet 10, and FIG. 2B is a partially enlarged cross-sectional view taken along the line 1B-1B of the anisotropic conductive sheet 10 in FIG. 2A.

As shown in FIGS. 2A and 2B, the anisotropic conductive sheet 10 includes an insulating sheet 11 having a plurality of through holes 12 and a plurality of sheets disposed corresponding to each of the plurality of through holes 12. It has a conductive layer 13 (for example, two conductive layers 13 surrounded by broken lines in FIG. 2B).

The insulating sheet 11 is a sheet in which a silicone resin layer 11A and two heat-resistant resin layers 11B and 11C are laminated. The silicone resin contained in the silicone resin layer 11A is the same as the silicone resin contained in the silicone resin portion of the above-described composite material to be plated. In addition, the heat-resistant resin contained in the heat-resistant resin layers 11B and 11C is the same as the heat-resistant resin contained in the heat-resistant resin portion of the above-described composite material to be plated. The two heat-resistant resin layers 11B and 11C may be layers containing the same resin, or may be layers containing different resins. Additionally, the insulating sheet 11 may include an adhesive layer (not shown) between the silicone resin layer 11A and the heat-resistant resin layers 11B and 11C, if necessary.

On the other hand, the shape of the through hole 12 is not particularly limited and can be, for example, columnar. The through hole 12 may be cylindrical, prismatic, or have other shapes. The shape of the cross section perpendicular to the axial direction of the through hole 12 is, for example, circular, oval, square, or other polygon.

The through hole 12 may be a hole formed by any method, for example, may be a hole formed by mechanical processing (for example, press processing, punch processing), or may be a hole formed by laser processing.

On the other hand, the thickness of the insulating sheet 11 is sufficient to insulate the substrate of the electrical inspection device and the object to be inspected, and is usually preferably 40 to 500 μm, more preferably 100 to 300 μm.

On the other hand, the conductive layer 13 is a layer formed on the outer wall 12c of the through hole 12 by electroless plating. The unit of conductive layer 13 surrounded by a broken line functions as one conductive path (see FIG. 2B). The volume resistivity of the material constituting the conductive layer 13 is not particularly limited as long as sufficient conduction is obtained, but for example, it is preferably 1.0 × 10 × 10 ^-4 Ω·cm or less, and 1.0 × 10 × 10 ^-6 to 1.0×10 ^-9 Ω·cm is more preferable. The volume resistivity of the material constituting the conductive layer 13 can be measured by the method described in ASTM D 991.

The thickness of the conductive layer 13 is not particularly limited as long as it is within a range where sufficient conduction is obtained. Usually, the thickness of the conductive layer 13 is preferably 0.1 to 5 μm. If the thickness of the conductive layer 13 is above a certain level, sufficient conduction is easy to obtain, and if the thickness is below a certain level, the through hole 12 may be blocked, or the terminal of the inspection object may be damaged due to contact with the conductive layer 13. difficult. On the other hand, the thickness of the conductive layer 13 is the thickness in the direction perpendicular to the thickness direction of the insulating sheet 11.

Meanwhile, in FIG. 2B, the conductive layer 13 is formed only on the outer wall 12c of the through hole 12, but the conductive layer 13 is formed on the first surface or the second surface of the insulating sheet 11. It may also be formed on the surface.

(2) Manufacturing method of anisotropic conductive sheet

An anisotropic conductive sheet includes a heat-resistant resin layer containing a heat-resistant resin and a silicone resin layer containing a silicone resin, which are laminated in the thickness direction, with a first surface located on one side of the thickness direction and a first surface located on the other side. A process of preparing an insulating sheet having a through hole penetrating two sides (hereinafter also referred to as “insulating sheet preparation process”) and a process of treating the outer wall of the through hole of the insulating sheet with an alkaline solution (hereinafter referred to as “insulation sheet preparation process”). a process of irradiating plasma to an outer wall treated with an alkaline solution (hereinafter also referred to as a “plasma irradiation process”); and a process of irradiating a cationic catalyst-containing liquid to the plasma-treated outer wall. A method including a step of contacting the catalyst (hereinafter also referred to as the “catalyst contact step”) and a step of performing an electroless plating treatment on the outer wall brought into contact with the catalyst-containing liquid (hereinafter also referred to as the “electroless plating treatment step”). It can be manufactured. Steps other than these may be included as long as the effect and purpose of the present invention are not impaired.

In the insulating sheet preparation process, a heat-resistant resin layer containing the above-described heat-resistant resin and a silicone resin layer containing a silicone resin are laminated in the thickness direction, with a first surface located on one side in the thickness direction and a silicone resin layer on the other side. Prepare an insulating sheet having a through hole penetrating the second surface where the insulation sheet is positioned. In the insulating sheet preparation step, for example, a heat-resistant resin layer and a silicone resin layer may be laminated or a through hole may be formed.

In the alkaline solution treatment process, the outer wall of the through hole of the insulating sheet is treated with an alkaline solution. The alkaline solution treatment process may be similar to the alkaline solution treatment process of the above-described method of manufacturing a composite material to be plated.

In the plasma irradiation process, plasma treatment is performed on the outer wall of the through hole of the insulating sheet. The plasma irradiation process can be performed similarly to the plasma irradiation process of the above-mentioned method of manufacturing a composite material to be plated, for example, by performing oxygen plasma treatment on both sides of the insulating sheet, respectively, to form COOH groups on the outer wall of the through hole. It is possible to introduce Si-OH groups.

In the catalyst contact process, a cationic catalyst-containing liquid is brought into contact with the outer wall of the through hole that has been plasma treated. The catalyst contact process can be performed similarly to the catalyst contact process of the above-mentioned method for manufacturing a composite to be plated, but, for example, masking is performed by applying a resist or the like to prevent the catalyst from adhering to areas other than the outer wall of the through hole. It's okay too.

In the electroless plating process, electroless plating treatment is performed on the outer wall brought into contact with the catalyst-containing liquid. The electroless plating process may be similar to the electroless plating process of the above-described method of manufacturing a composite material to be plated, but, for example, a resist or the like may be applied to prevent a plating layer from being formed in areas other than the outer wall of the through hole. Masking processing may be performed. In addition, after forming a plating layer in areas other than the outer wall of the through hole (for example, the first or second surface of the insulating sheet), the plating layer in unnecessary areas may be removed.

In the method of manufacturing the anisotropic conductive sheet, annealing treatment, etc. may be performed as necessary, as in the method of manufacturing the above-described composite material to be plated.

Example

Below, the present invention is explained with reference to examples. The scope of the present invention is not to be construed as limited by the examples.

[Example 1]

(1) Preparation of composite material

Two heat-resistant resin films (EXPEEK manufactured by Kurabo Corporation) containing polyetheretherketone (PEEK) and having a thickness of 9 μm were prepared. Next, a silicone resin film (manufactured by Fuso Rubber Sangyo Co., Ltd.) containing polydimethylsiloxane (PDMS) and having a thickness of 300 μm was prepared. Then, heat-resistant resin films were placed on both sides of the silicone resin film, and they were adhered. Subsequently, a through hole was created to connect the heat resistant resin film surface (first side) on one side of the laminate to the heat resistant resin film surface (second side) on the other side. The through hole was produced with a laser. Additionally, the shape of the through hole was cylindrical with a diameter of 70 μm.

(2) Treatment and neutralization treatment with alkaline solution

The composite material was immersed in a 50°C sodium hydroxide solution (concentration 20 g/L, pH 13.4) for 30 minutes. Additionally, simultaneously with immersion, ultrasonic treatment (frequency 40 kHz) was also performed. Afterwards, the composite material was taken out and immersed in sulfuric acid (concentrated sulfuric acid: 100 ml/L solution) for 1 minute. At this time, ultrasonic treatment (frequency 40 kHz) was also performed.

(3) Vacuum plasma treatment

Subsequently, vacuum plasma treatment was performed for 1 minute from the first and second surfaces of the composite material, respectively. Plasma processing conditions are as follows.

(Plasma treatment conditions)

Plasma irradiation device: Yamato Science Company PDC210

Output: 100W

Atmospheric pressure: 5Pa

Oxygen supply: 20ml/min

Oscillation frequency: 13.56MHz

High frequency output: 125W

Processing time: 1 minute

(4) Treatment with catalyst-containing liquid

The composite material after the plasma treatment was immersed in a complex solution of palladium ions (Top SAPINA Catalyst, manufactured by Okuno Pharmaceutical Industries, Ltd., palladium concentration 100 ppm) heated to 40°C for 2 minutes, and palladium ions were attached to the surface of the composite material. After that, it was immersed in a reducing agent (Top SAPINA accelerator manufactured by Okuno Pharmaceutical Industries, Ltd.) for 1.5 minutes to reduce palladium ions.

(5) Electroless plating treatment

The above composite was added to a solution at 35°C containing ATS Adcopper IW-A: 50 mL, ATS Adcopper IW-M: 80 mL, ATS Adcopper C: 15 mL, and ATS Adcopper R-N: 3 mL (all manufactured by Okuno Pharmaceutical Industries, Ltd.). It was soaked for 15 minutes.

(6) Annealing treatment

The composite material after the electroless plating treatment was annealed at 110°C for 20 minutes to obtain a composite material to be plated (anisotropic conductive sheet).

[Example 2]

A composite material to be plated was obtained in the same manner as in Example 1, except that the plasma output during plasma treatment was changed to 150 W.

[Example 3]

A composite material to be plated was obtained in the same manner as in Example 1, except that the type of heat-resistant resin film was changed to polyimide (PI) with a thickness of 7.5 μm (Kapton 30EN, manufactured by Toray-DuPont).

[Comparative Example 1]

A composite material to be plated was obtained in the same manner as in Example 1, except that treatment with an alkaline solution, neutralization treatment, and vacuum plasma treatment were not performed.

[Comparative Example 2]

A composite material to be plated was obtained in the same manner as in Example 1, except that neutralization treatment and vacuum plasma treatment were not performed.

[Comparative Example 3]

A composite material to be plated was obtained in the same manner as in Example 1, except that vacuum plasma treatment was not performed.

[Comparative Example 4]

A plated composite material was obtained in the same manner as in Example 1, except that corona treatment was performed under the following conditions instead of plasma treatment.

(Corona processing conditions)

Corona treatment device: TEC-4AX manufactured by Kasuga Electric Co., Ltd.

Output: 90W·0.4m/min

Discharge gap: 1mm

Atmosphere: Atmospheric pressure

Working temperature: 25℃

[Comparative Example 5]

A composite material to be plated was obtained in the same manner as in Example 1, except that treatment with an alkaline solution and neutralization treatment were not performed.

[Comparative Example 6]

After preparing the composite material, vacuum plasma treatment was performed, and then a plated composite material was obtained in the same manner as in Example 1, except that treatment with an alkaline solution and neutralization treatment were performed.

(evaluation)

For the plated composite materials produced in the above examples and comparative examples, a crosscut tape peeling test of the plating layer was performed in accordance with the crosscut test (JIS Z 1522). The results were evaluated based on the following criteria.

○: No peeling

△: Peeling 5% or less

×: Peeling exceeds 5%

As shown in Table 1 above, by subjecting the composite material to treatment with an alkaline solution, plasma irradiation, treatment with a catalyst-containing solution, and electroless plating treatment, adhesion to both the heat-resistant resin layer and the silicone resin layer was improved. A good plating layer could be formed (Examples 1 to 3). On the other hand, when plasma irradiation is not performed (Comparative Examples 1 to 4), when treatment with an alkaline solution is not performed (Comparative Examples 1 and 5), or when the order of plasma irradiation and treatment with an alkaline solution is reversed (Comparative Examples In both cases, such as Example 6), it was confirmed that plating did not precipitate, peeling occurred during plating, and a plating layer with sufficient adhesion was not obtained.

In addition, in each Example and Comparative Example, the amount of COOH groups on the surface of the heat-resistant resin part before contact with the catalyst-containing liquid is shown in Figure 3, and the amount of Si-OH groups on the surface of the silicone resin part before contact with the catalyst-containing liquid is shown in Figure 3. It is shown in 4. The amount of COOH group and the amount of Si-OH group were measured by analyzing them by did it As shown in Figures 3 and 4, by performing treatment with an alkaline solution and plasma irradiation in this order, both the amount of COOH groups and the amount of Si-OH groups increased (Example 1). Additionally, as is clear from the results in the case of only plasma irradiation (Comparative Example 5), although the amount of COOH groups and the amount of Si-OH groups simply increased, the adhesion of the plating layer did not increase. In other words, it is believed that not only plasma treatment but also alkaline solution treatment is very important for the adhesion of the plating layer of electroless plating.

This application claims priority based on Japanese Patent Application No. 2021-161758, filed on September 30, 2021. The entire content described in the application specification and drawings is incorporated into the present application specification.

According to the method for producing a plated composite material of the present invention, a plated composite material with high adhesion between the composite material and the plating layer can be manufactured. Therefore, it is very useful when manufacturing anisotropic conductive sheets and various products.

10 Anisotropic conductive sheet
11 insulation sheet
11A silicone resin layer
11B, 11C heat-resistant resin layer
12 through hole
12c exterior wall
13 Conductive layer

Claims (5)

A process of preparing a composite material having a heat-resistant resin portion containing a heat-resistant resin and a silicone resin portion containing a silicone resin;
A process of treating the plated area of the composite with an alkaline solution;
A process of irradiating plasma to the plated area treated with the alkaline solution;
A step of contacting the plated area irradiated with the plasma with a cationic catalyst-containing liquid;
A process of performing electroless plating treatment on the area to be plated, which has been brought into contact with the catalyst-containing liquid.
Including,
The area to be plated includes at least a portion of the heat-resistant resin portion and at least a portion of the silicone resin portion,
Method for manufacturing a plated composite. According to claim 1,
wherein the plasma is oxygen plasma,
Method for manufacturing a plated composite. The method of claim 1 or 2,
The high-frequency output of the plasma is 75W to 150W,
Method for manufacturing a plated composite. The method according to any one of claims 1 to 3,
In the composite material, the heat-resistant resin portion and the silicone resin portion are stacked in the thickness direction,
The composite material further has a through hole penetrating a first surface located on one side of the thickness direction and a second surface located on the other side,
The area to be plated is the outer wall of the through hole,
Method for manufacturing a plated composite. A heat-resistant resin layer containing a heat-resistant resin and a silicone resin layer containing a silicone resin are laminated in the thickness direction, and penetrate through a first surface located on one side of the thickness direction and a second surface located on the other side. A process of preparing an insulating sheet having a through hole,
A step of treating the outer wall of the through hole of the insulating sheet with an alkaline solution;
A process of irradiating plasma to the outer wall treated with the alkaline solution;
A step of bringing a cationic catalyst-containing liquid into contact with the outer wall irradiated with the plasma;
A process of performing electroless plating treatment on the outer wall brought into contact with the catalyst-containing liquid.
Including,
Method for producing an anisotropic conductive sheet.