JP4734875B2 - Insulator for additive plating, substrate with additive plating metal film - Google Patents

Description

The present invention, by plating to form a circuit on the surface of the insulator (insulating substrate), a luer di Restorative plated insulator used in manufacturing the printed wiring board, relates additive plated metal film-coated substrate, The present invention relates to a surface treatment technique for improving the adhesion of a plated circuit to an insulating substrate without performing a surface treatment such as desmear that is generally performed.

  In recent years, due to the improvement in the wiring density of printed wiring boards, the miniaturization of wiring boards and the shortening of the wiring distance between mounted components have progressed, and electronic devices have become more sophisticated and smaller and thinner. In general, a wiring board is manufactured as a multilayer wiring board by a build-up multilayering method or the like in which a conductor layer is laminated via an insulating layer.

  For such a wiring board, a copper-clad laminate in which a metal foil such as a copper foil is laminated and integrated in advance with an insulating substrate, and a wiring pattern is formed by performing an etching method on the copper-clad laminate In some cases, a conductor layer is directly formed on the surface of the insulating substrate by plating or the like, and the conductor layer is etched to form a predetermined wiring pattern. In the latter case, in order to improve the adhesion between the conductor layer and the insulating layer, a surface roughening treatment (desmear treatment) has been conventionally performed on the surface of the insulating layer before plating. The roughening treatment is usually performed by etching the surface of the insulating layer (resin layer) using an etchant such as potassium permanganate or sodium permanganate (see, for example, Patent Document 1). ).

Here, the general plating method will be described in detail. This method includes a pretreatment step such as degreasing of the resin surface, an etching treatment step, a catalyzing treatment step, an accelerating treatment step, an electroless copper plating treatment step, It consists of an electrolytic copper plating process. The reason why the plating process is performed after performing various processing steps without directly performing the plating process on the surface of the insulating substrate is that the resin has a hydrophobic property that is difficult to wet with water. That is, if the plating process is performed on the surface of the insulating substrate as it is, a metal film cannot be formed on the surface. When the surface treatment is performed in an aqueous solution such as plating, the surface of the insulating substrate must be made hydrophilic so that it can easily get wet with water. Furthermore, in order for the surface of the insulating substrate and the plated metal to be in close contact with each other, the surface of the insulating substrate is made hydrophilic and activated by creating polar groups on the resin surface. It is necessary to carry out a roughening treatment having unevenness. This roughening treatment is performed in the order of a swelling process with a swelling liquid such as an organic solvent, an etching process with an etching liquid such as sodium permanganate, and a neutralization process with a neutralizing liquid such as sulfuric acid. The surface of the insulating substrate is roughened. This process is an etching process. Next, in order to activate the palladium by depositing plating nuclei on the resin surface, the insulating substrate is immersed in a catalyzing solution containing palladium chloride and tin chloride, and the catalyst metal is adsorbed on the resin surface. This process is a catalyzing process. When the catalyzing process is performed in this way, the complex salt of palladium and tin is adsorbed on the surface of the insulating substrate. Therefore, in the next accelerating process, an accelerator containing hydrochloric acid, sulfuric acid, NH ₄ F.HF, or the like is used. Palladium metal serving as a plating nucleus can be deposited on the resin surface in the rating treatment solution. Then, in the electroless copper plating process, the copper metal is electrolessly plated on the resin surface by the catalytic action of the plating nuclei deposited on the resin surface, and a copper film is formed on the resin surface. The copper film formed by electroless copper plating has a role of a power feeding layer for performing electrolytic copper plating, and usually has a thickness of about 0.5 to 2.0 μm. Thereafter, in the electrolytic copper plating process, electrolytic copper plating is performed until a predetermined thickness that can be used for a wiring pattern or the like is formed, thereby forming a copper film.

  The above is a general plating method, but as a technique to improve the adhesion between the conductor layer and the insulating layer, various methods for electroless plating on the surface after modifying the surface of the insulating substrate are proposed. Has been. For example, a method has been proposed in which an insulating substrate is placed in an amine compound gas or amide compound gas atmosphere, and the surface of the insulating substrate is irradiated with an ultraviolet laser, followed by electroless plating (see, for example, Patent Document 2). .

  In addition, as a pretreatment for performing electroless plating on an insulating substrate, a method of irradiating the surface of the insulating substrate with ultraviolet rays of a predetermined irradiation amount or more and then performing electroless plating on the surface of the insulating substrate has been proposed. (For example, refer to Patent Document 3).

  In addition, a method for improving adhesion by performing a surface treatment of contacting with an alkaline solution containing a nonionic surfactant having a polyoxyethylene bond has been proposed (for example, see Patent Document 4). .

  In addition, after surface modification of the insulating substrate by ultraviolet irradiation, the silane coupling agent having an amino functional group is adsorbed on the surface of the insulating substrate to promote the application of the tin-palladium catalyst, thereby electroless plating. There has also been proposed a method of improving the adhesion of the metal film formed by the above to an insulating substrate (see, for example, Patent Document 5).

  Also, a wiring board comprising an organic insulating layer made of a polyimide resin formed by electrophoresis on a metal plate and having a meta-coordinating diamine as a component, and a conductor formed by plating thereon, There has been proposed a wiring board in which a conductor is provided with plating nuclei before the organic insulating layer is thermally cured and plated after curing (see, for example, Patent Document 6).

  Also, in a method of manufacturing a printed wiring board in which signal circuits are patterned on an insulating resin, after a metal that exerts a throwing effect is deposited on the surface of the insulating resin, the metal is removed by etching, and after the metal is removed A method of increasing the adhesion of metal plating to the resin surface by performing metal plating on the resin surface has been proposed (see, for example, Patent Document 7).

Further, a method relating to a method for manufacturing a printed wiring board by a full additive method has been proposed (see, for example, Patent Document 8).
JP 2002-57456 A JP-A-6-87964 JP-A-8-253869 JP-A-10-88361 JP-A-10-310873 Japanese Patent No. 2945129 JP-A-10-13016 Japanese Patent Laid-Open No. 5-29762

  Usually, in the additive method, a roughened surface (uneven surface) is formed on the surface of the insulating layer by the roughening treatment, and a conductor is filled in the concave portion of the roughened surface, thereby obtaining an anchor effect. Will be in close contact with the insulating layer. However, when the irregularities on the surface of the insulating layer become large, the irregularities on the surface adversely affect the accuracy of pattern formation when etching the conductor layer to form a wiring pattern, so that an extremely fine wiring pattern can be accurately formed. There was a problem that could not. In the case of the conventional roughening treatment, the surface roughness is about Rmax: 4 to 5 μm. However, Patent Documents 1 and 6 described above describe a technique for reducing the surface roughness to Rmax: 1 μm or less. Yes.

  In addition, when the surface roughness of the insulating layer increases, there is a problem that transmission loss of a high frequency signal, which is one of the electrical characteristics of the wiring board, increases. Further, when the surface roughness of the insulating layer is increased, there is a problem that the migration resistance is lowered. Therefore, it is necessary to make the surface roughness of the insulating layer as small as possible, and there is a need for a technique that can improve the adhesion between the insulating layer and the conductor layer. From this point of view, as described above, there has been proposed a method of subjecting the surface of an insulating substrate to plasma treatment, ion beam irradiation, and ultraviolet irradiation. In this case, it is considered that —OH groups and —NH groups generated by plasma treatment, ultraviolet treatment or the like contribute to the improvement of the adhesion of electroless plating. However, in order to effectively generate the functional groups as described above, it is necessary to consider the composition of the insulating substrate, and there is a problem that the resin design is limited.

  The above method is based on the premise that the surface of the insulating substrate is etched to roughen the surface. In this case, the etching process is generally performed using a mixed solution of chromic acid / sulfuric acid, dichromic acid / sulfuric acid. This is performed by immersing the insulating substrate in a strongly oxidizing etching solution such as a mixed solution, chloric acid, sulfuric acid / perchloric acid mixed solution, or the like. However, since such an etching solution is a chemical solution with high danger and pollution, it is necessary to pay careful attention to its handling and discharge treatment. The burden is large. In addition, in order to more easily roughen the resin surface by etching, it is necessary to take into account the fact that some components that are easily etched are mixed in the resin in advance, which limits the properties of the cured resin. There is also a problem that it will be. In addition to this, it is necessary to prepare a treatment agent for promoting the surface modification of the insulating substrate separately from the normal treatment liquid, which causes a problem that the number of treatment steps is increased and the treatment cost is increased. Furthermore, it is necessary to install an ultraviolet irradiation device and a plasma processing device, which causes an increase in equipment cost and is a major obstacle to supplying inexpensive products.

The present invention has been made in view of the above points, and is suitably used for manufacturing a multilayer printed wiring board by a buildup method or the like in which a conductor layer is laminated via an insulating layer. When forming a conductor layer on the surface of an insulating layer by electroplating, the surface roughness of the insulating layer can be reduced, and the adhesion between the insulating layer and the conductor layer can be increased, resulting in an extremely fine wiring pattern. make it possible to form, as a material capable of further producing an excellent wiring board electrical properties, it is an object to provide a di Restorative plated insulator, an additive plating metal film-coated substrate .

Additive plating insulator 6 according to the present invention, the metal body 1 to roughen the surface by bonding a sheet-like insulator 2 is formed with the metal body insulator 3, as the metal body 1, formed by the etching solution It has been the metal ions of the roughened surface 4 the etchant to what was deposited by precipitating metal particles 5 are used, together with the metal particles 5 are embedded in the insulating body 2, the metal body The metal body 1 of the attached insulator 3 is peeled off, the metal particles 5 are embedded in the surface layer of the insulator 2 as plating nuclei, and a part of the metal particles 5 are insulated. It is characterized by being exposed on the surface of the body 2 .

In the additive plating insulator 6, it is preferable ionization tendency of the metal particles 5 is smaller than the ionization tendency of the metal body 1.

In the additive plating insulator 6, it is preferable that the metal body 1 is an alloy containing iron.

In the additive plating insulator 6, it is preferable that the thickness of the metal body 1 is 20 to 150 [mu] m.

In the additive plating insulator 6, it is preferably formed by the roughened surface 7 is formed on the surface of the insulator 2.

In the additive plating insulator 6 is preferably made the roughened surface 7 of the insulator 2 had the following irregularities 1μm in surface roughness Ra.

In the additive plating insulator 6, it is preferable that the insulator 2 is made of a resin composition.

In the additive plating insulator 6, it is preferable that the insulator 2 is made of resin-impregnated base material.

In the additive plating insulator 6, it is preferable that the insulator 2 is made of those having an adhesive property.

Additive plating metal film-coated substrate 9 according to the present invention, the metal particles 5 exposed to the surface of the additive plating insulator 6 becomes a nucleus for plating, pre-Symbol metal coating 8 on the surface of the insulator 2 is plated It is characterized by being formed by.

In the additive plating metal coating with the substrate 9, it is preferable that the metal particles 5 is a metal mainly composed of copper.

According to the insulator for additive plating according to the present invention, the surface of the insulator is prevented from being oxidized until the surface is plated, the roughened surface of the metal body is transferred to the surface of the insulator, and the roughened surface of the metal body. By attaching the metal particles serving as the plating nuclei to the surface of the insulator, the metal body is peeled off, so that the process up to the conventional electroless plating process can be made unnecessary. And it is used suitably for manufacturing a multilayer printed wiring board by the buildup method etc. which laminate | stack a conductor layer through an insulating layer, and forms a conductor layer on the surface of an insulating layer by electroless plating and electrolytic plating In this case, the surface roughness of the insulating layer can be reduced, and the adhesion between the insulating layer and the conductor layer can be increased, so that a very fine wiring pattern can be formed, and the electrical characteristics are excellent. A wiring board can be manufactured. In addition, it is possible to dispense with a treatment for applying a catalyst such as palladium.

According to additive plated metal film-attached substrate according to the present onset bright, in which it is possible to easily form a fine wiring pattern.

  Embodiments of the present invention will be described below.

Metallic body with the insulator 3 is a metal body 1 to roughen the surface is that formed by laminating the insulator 2, this basic technique has provided the present inventors have already (JP (See 2004-228551).

  Briefly explaining the technical content, copper particles are deposited on the surface of a stainless steel foil, and electrolytic copper plating is performed using the copper particles as a plating nucleus to form a wiring pattern on the stainless steel foil. The above publication also describes a reaction in which iron ions are replaced with copper ions and copper is precipitated on the surface while the surface of the stainless steel is roughened. Then, solder the components on the wiring pattern formed on the surface of the stainless steel foil, heat mold with the insulating layer (resin layer), embed the components and circuits in the resin, and peel off the stainless steel foil after curing. Components and circuits are transferred to the layer side, and only the stainless steel foil is peeled off to produce a component built-in circuit board. The feature of this technology is that it is usually not possible to apply plating with good adhesion to the surface of stainless steel foil, but by depositing copper by substitution reaction with iron ions, the surface of the metal has a very fine surface roughness. Copper is deposited in a complicated manner, the adhesion between the stainless steel foil and the plated copper is increased, and the components and circuits are not peeled off by the subsequent solder mounting, but after being embedded and transferred to the insulating layer, Since the stainless steel foil and the copper plating circuit can be easily peeled off, the stainless steel foil can be used as a transfer foil on which components are mounted.

  We have developed a new plating nucleation method using some of the technologies described above. The outline is that the copper particles are deposited on the surface of the stainless steel foil and formed integrally with the insulating layer, whereby a part of the copper particles are transferred to the insulating layer side, and the copper particles are embedded in the insulating layer. Thus, copper particles exposed on the surface of the insulating layer can be obtained. And we perform electroless copper plating using this copper particle as a plating nucleus, deposit copper, and then deposit copper to a predetermined thickness by electrolytic copper plating, so that the additive metal film has very good adhesion Succeeded in obtaining a substrate with eight. In addition, in this case, an etching process such as desmear is not required, and there is no restriction on the resin composition. Therefore, the resin design can be made with priority on the cured product characteristics. Also, the copper particles that are the core of the plating are embedded in the insulating layer, and the plating circuit is formed by the same copper growth as the copper particles, so the adhesion between the insulating layer and the circuit is very high and embedded. Since the produced copper particles have a very fine size, the accuracy at the time of circuit formation is not affected at all. If anything, the surface roughness of the stainless steel foil is 1 μm or less in Ra, so that only the unevenness becomes the unevenness on the lower side of the copper circuit. If such a stainless steel foil is produced in advance by a continuous construction method and a resin sheet with a metal foil is produced by applying a resin to the foil and drying it, it can be used as a material for additive plating formation that can be used in the build-up construction method. It can be done.

  Hereinafter, the present invention will be described in more detail.

  Although it does not specifically limit as the metal body 1 in this invention, For example, the metal body 1 containing iron can be used. In particular, it is preferable to use a material having a chromium content of 10 to 20% by mass and a nickel content of 0 to 15% by mass in order to facilitate roughening when a surface roughening treatment is performed. Examples of such a metal body 1 include an alloy containing iron, for example, a stainless material such as SUS301 or SUS304. In particular, when the metal body 1 is an alloy containing iron such as stainless steel, the core of plating can be easily formed by depositing metal particles 5 on the surface. In addition, since the stainless steel material having the above composition is widely used and easily available, the manufacturing cost can be reduced. Although the surface can be roughened with materials other than those described above, it becomes difficult to control the concentration of the etching solution for the roughening treatment.

  In addition, as described later, the metal body 1 is temporarily peeled after being bonded to the insulator 2, but in order to improve the peelability at this time, the thickness of the metal body 1 is 20 to 20 mm. A range of 150 μm is preferable. With such a thickness, when the metal body 1 is peeled from the insulator 2, the metal body 1 can be easily peeled while being turned up and bent from the insulator 2, and at this time, the insulator 2 On the other hand, it is possible to prevent the insulator 2 from being damaged by suppressing excessive stress. That is, when the metal body 1 becomes a thin film, flexible material processing is possible. However, when the thickness of the metal body 1 is less than 20 μm, the waist is lost and wrinkles are easily formed, so that the smoothness of the surface may be adversely affected during molding. When the insulator 2 is flexible, or when the metal body 1 requires sufficient rigidity due to processing limitations, the thickness of the metal body 1 may exceed 150 μm.

  Then, the surface of the metal body 1 as described above is roughened, and metal particles 5 are adhered to the roughened surface 4. This state is shown in FIG. Below, the case where the metal body 1 is the stainless steel material 10 (iron-containing) is mainly demonstrated for convenience, but it cannot be overemphasized that it is not limited to this.

  The surface roughening of the metal body 1 and the adhesion of the metal particles 5 to the roughened surface 4 can be performed at a time. That is, a roughened surface 4 is formed on the stainless steel material 10 by bringing a predetermined etching solution into contact with the surface of the stainless steel material 10 to form a roughened surface 4, and at the same time, metal ions in the etchant are roughened on the roughened surface 4. And deposited as metal particles 5. At this time, an etching solution containing iron ions and ions of a metal (for example, copper) having a smaller ionization tendency than iron is used. Thus, when the ionization tendency of the metal particles 5 is smaller than the ionization tendency of the metal body 1, the metal particles 5 can be deposited and adhered to the surface of the metal body 1, and the metal deposited due to the difference in ionization tendency The particles 5 can be variously changed.

  In particular, the above etching solution contains ferric chloride or an alkaline etching solution (iron chloride etching solution) containing ferric chloride and ferrous chloride to contain iron ions. However, it is preferable to use a metal ion containing a metal ion having a small ionization tendency, and it is preferable to use a copper ion or a nickel ion as a metal ion having a smaller ionization tendency than iron. For example, if copper ions are contained in the etching solution, the copper particles 11 can be deposited and adhered to the roughened surface 4 of the metal body 1, but this becomes the core of electroless copper plating, and finally Can easily form a copper plating circuit as is generally used in the market.

  Here, the processing of normal stainless steel 10 or the like is performed by using an etching solution having a redox potential of 660 mV or more, and processing with less side etching is performed. However, the present invention forms an unevenness that improves adhesion. In order to perform only surface roughening, the roughening treatment is preferably performed with an etching solution having a lower oxidation-reduction potential than ordinary stainless steel processing. Specifically, as an alkaline etching solution containing ferric chloride or containing ferric chloride and ferrous chloride, the specific gravity is 1.1 to 1.7, and the redox potential is It is preferable to use the thing of the range of 400-660 mV.

  When the etching solution as described above is used as the surface treatment solution for the stainless steel material 10, it is considered that the following two reactions mainly occur simultaneously on the surface of the stainless steel material 10, thereby enabling the surface treatment.

  The first reaction is a reaction for roughening the surface of the stainless steel material 10 as described below.

2FeCl ₃ + Fe → 3FeCl ₂
This reaction is a reaction for etching iron, which is the main component of the stainless steel 10. That is, this reaction is considered to be a reaction in which the iron in the stainless steel material 10 reacts with the trivalent iron ions in the etching solution and dissolves as divalent iron ions. Note that, in the sense that iron is dissolved, it is preferable to use a general etching solution in a state where the oxidation-reduction potential is as high as 660 to 700 mV. Since only the surface treatment of the metal body 1 such as 10 is required, it is preferable to use the etching solution in a state where the oxidation-reduction potential is 400 to 660 mV and the etching power is weak. Surface roughening with almost no change in thickness before and after the treatment is possible.

  Next, the second reaction is a reaction in which a metal such as copper, which has a lower ionization tendency than iron, is deposited and adhered to the surface of the stainless steel 10 as shown below. The following formula is for the case where copper ions are contained by containing copper chloride in the etching solution.

CuCl ₂ + Fe → FeCl ₂ + Cu
In this reaction, by containing metal ions such as copper ions having a smaller ionization tendency than iron in the etching solution, the metal ions react with iron which is the main component of the stainless steel material 10, and iron Is ionized by etching, but metal ions having a smaller ionization tendency than iron are deposited and deposited on the roughened surface 4 of the stainless steel 10 as metal.

  2A, the surface of the metal body 1 such as the stainless steel 10 can be formed on the roughened surface 4 as well as the copper particles 11 on the roughened surface 4 as shown in FIG. The metal particles 5 such as can be attached in a state having appropriate adhesiveness.

  As described above, according to the present invention, the roughened surface 4 is formed by using an etchant containing metal ions having a smaller ionization tendency than iron in a commonly used iron chloride etchant, It has become possible to obtain a roughened surface 4 in which different metal particles 5 adhered to the surface, which cannot be obtained only by roughening with a conventional etching technique. Here, it is preferable that the specific gravity of the etching solution containing metal ions having a smaller ionization tendency than iron in the iron chloride etching solution is 1.2 to 1.7, and the oxidation-reduction potential is 400 to 660 mV. It is preferable. In addition, when transferring the metal particles 5 to a sheet material such as a resin sheet, which will be described later, the metal particles 5 can be transferred in a temperature range of about 100 ° C., and transfer under conditions that do not promote curing of the resin sheet or the like. It becomes possible.

  As described above, when using an alkali etching solution such as a ferric chloride solution in which ions of a metal having a smaller ionization tendency than iron are used, a metal having a smaller ionization tendency than iron in the etching solution. The ion content is preferably 0.01 to 30% by mass. If this content is less than 0.01% by mass, the attached metal particles 5 may be too small to be used as a plating nucleus. On the other hand, if the content exceeds 30% by mass, the viscosity of the treatment liquid becomes thick and the treatment efficiency may be lowered. Therefore, it is preferable to treat with a treatment liquid having a certain concentration.

  The content of the metal particles 5 (metal particles having a smaller ionization tendency than iron) on the roughened surface 4 is not particularly limited, and when processing using an etching solution is performed, the processing time required for roughening is required. Depending on the processing conditions, etc., a suitable amount of adhesion may also vary. For example, when the surface treatment is performed with an etching solution having a smaller ionization tendency than that of iron with a metal ion content, the treatment time is increased, and when the surface treatment is performed with an etching solution having a higher content, the treatment time is shortened. It is necessary to optimize the adhesion amount of the metal particles 5 to be deposited on the roughened surface 4 by changing the processing conditions, for example.

The roughened surface 4 of the metal body 1 is preferably formed so that the surface roughness Ra is 1.0 μm or less. The surface roughness Ra is obtained by measuring with a cut-off value λ _c = 0.80 mm and a measurement length L = λ _c × 5 = 4.0 mm based on JIS B0601. Here, the smaller the surface roughness Ra is, the higher the accuracy of the subsequent circuit formation can be expected, but the practical lower limit is 0.1 μm. The surface roughness Ra has a relationship with the deposition rate of the metal particles 5, but the important thing is to optimize the conditions for the deposition amount of the metal particles 5 by depositing more metal particles 5. . As will be described later, the metal body 1 is temporarily bonded to the insulator 2 and then peeled off. However, since the roughened surface 4 of the metal body 1 is transferred to the surface of the insulator 2, the metal body 1 When the surface roughness Ra of the roughened surface 4 of the body 1 is 1.0 μm or less, the surface roughness Ra of the roughened surface 7 of the insulator 2 is 1.0 μm or less, and there are fine irregularities. Therefore, the fine processing of the wiring pattern can be performed very easily.

  Next, the respective manufacturing methods of the insulator with metal body 3, the insulator for additive plating 6, and the substrate with additive plating metal film 9 will be described in order with reference to the drawings.

  As shown in FIGS. 1A and 1B, the insulator 3 with a metal body can be manufactured by bonding a metal body 1 having a roughened surface to the insulator 2. As the metal body 1, as described above, the metal body 5 with the metal particles 5 attached to the roughened surface 4 is used. FIG. 2A is an enlarged view of the portion A in FIG. Then, the roughened surface 4 of the metal body 1 is transferred to the surface of the insulator 2 by the above bonding, and at the same time, the metal particles 5 are embedded in the insulator 2 as shown in FIG. Become. In this way, the insulator 3 with the metal body is formed. According to this, the surface of the insulator 2 is prevented from being oxidized until the surface of the insulator 2 is plated, and the metal body 1 is applied to the surface of the insulator 2. The transfer of the roughened surface 4 and the metal particles 5 serving as plating nuclei attached to the roughened surface 4 of the metal body 1 are embedded in the surface of the insulator 2, whereby the metal body 1 is peeled off, so that the conventional The process up to the electroless plating process can be eliminated.

  Here, the insulator 2 can be formed of an electrically insulating thermosetting resin composition / thermoplastic resin composition such as an epoxy resin composition. That is, for example, the above resin composition is formed into a sheet shape, and this is heated and dried by impregnating the resin composition into a semi-cured resin sheet, a glass woven fabric, an organic fiber sheet, or the like. The insulator 2 can be formed by using a sheet material composed of an electrically insulating resin composition in a B-stage state, such as a prepreg that has been dried and semi-cured. The insulator 2 can be formed by laminating and integrating a plurality of sheet materials in addition to being formed by a single sheet material. As described above, when the insulator 2 is made of a resin composition, the resin composition can be subjected to additive plating on a thermosetting film material, a thermoplastic film material, or the like by forming a film. It is. Further, when the insulator 2 is made of a resin-impregnated base material, additive plating can be applied to a material in which a glass base material, an organic fiber base material, or the like is impregnated with a resin. Moreover, you may form the insulator 2 with what has adhesiveness like a varnish. In this case, the insulator 2 can be formed by applying varnish to the roughened surface 4 of the metal body 1 and drying it. It can be suitably used in a build-up multi-layer method, and can provide an optimum material for forming an additive plating circuit.

  Then, as shown in FIGS. 1 (a) and 1 (b), when the roughened surface 4 of the metal body 1 (stainless steel material 10) is opposed to the insulator 2 and is heated and pressed to form a laminate, FIG. 2 (b) is obtained. As shown, the metal particles 5 (copper particles 11) attached to the roughened surface 4 of the metal body 1 are embedded in the insulator 2. At the same time, the roughened surface 4 of the metal body 1 is transferred to the insulator 2. Thereafter, as shown in FIG. 1C, when the metal body 1 is peeled off, the metal particles 5 are peeled off from the metal body 1 and remain on the insulator 2 to obtain an additive plating insulator 6. FIG. 2 (c) is an enlarged view of the portion C in FIG. 1 (c). As shown in this figure, metal particles 5 are embedded in the surface layer portion of the additive plating insulator 6, A part of each metal particle 5 is exposed on the surface of the insulator 2. Each metal particle 5 does not protrude from the roughened surface 7, but a part of the outer surface of each metal particle 5 constitutes a part of the roughened surface 7 of the insulator 2. Since the exposed metal particles 5 can be used as nuclei for plating, conventional treatments for applying a catalyst such as palladium can be made unnecessary.

  In addition, since the roughened surface 7 is formed on the surface of the insulator 2, a chemical roughening treatment such as desmear can be eliminated. In FIG. 1, the roughened surface 7 in which the metal particles 5 are embedded only on one side of the insulator 2 is formed, but the metal body 1 whose surface is roughened is formed on both sides of the insulator 2. The roughened surface 7 in which the metal particles 5 are embedded on both sides of the insulator 2 may be formed by bonding.

  Further, since the roughened surface 4 of the metal body 1 is transferred to the surface of the insulator 2, the surface roughness Ra of the roughened surface 4 of the metal body 1 is 1.0 μm or less. The surface 7 also has unevenness with a surface roughness Ra of 1 μm or less. As a result, when the surface roughness is 1 μm or less, fine processing of the wiring pattern can be performed very easily.

  Note that the heat and pressure molding when the metal body 1 is bonded to the insulator 2 is performed under the condition that the insulator 2 after the molding is maintained in the B stage state or the condition that the insulator 2 is in the C stage state.

  Next, the metal particles 5 exposed on the surface of the additive plating insulator 6 shown in FIG. 1 (c) are used as plating nuclei and are subjected to general electroless plating and electrolytic plating to thereby achieve the above insulation. A metal film 8 can be formed on the surface of the body 2, and a substrate 9 with an additive plating metal film as shown in FIG. 1 (d) can be obtained. 3 and 4 show how the metal film 8 grows by electroless plating and electrolytic plating. First, in the initial stage of electroless plating, as shown in FIG. 4 (E portion in FIG. 3A), each metal particle 5 exposed on the roughened surface 7 of the insulator 2 is plated with a nucleus. As a result, a metal film 8 is formed. When the electroless plating is further performed, a metal film 8 having a thickness of about 1 μm is grown as shown in FIG. This thin metal film 8 serves as a power feeding layer for electrolytic plating in the next process. Thereafter, when electrolytic plating is performed, a metal film 8 having a thickness of about 5 to 35 μm can be finally obtained as shown in FIG. FIG. 3C is an enlarged view of a portion D in FIG. In particular, if the metal particle 5 is a metal mainly composed of copper, a copper plating circuit generally used in the market can be formed. In addition, the metal film 8 obtained as described above should be unified with copper when copper particles 11 are used as the metal particles 5 and both the electroless plating and the electrolytic plating are subjected to copper plating. Thus, the circuit material has excellent continuity. In addition, since the metal particles 5 serving as plating nuclei are embedded in the insulator 2, the adhesion strength of the metal film 8 to the insulator 2 has a very high value.

  And, by forming a pattern with a predetermined resist on the substrate 9 with the additive plating metal film obtained as described above, and removing unnecessary portions by etching, a fine wiring pattern 12 can be easily formed, Finally, a printed wiring board (plated circuit board) as shown in FIG. 1 (e) can be obtained.

  Next, the example which manufactures a multilayer printed wiring board by the buildup method using the insulator 3 with a metal body mentioned above is demonstrated.

  First, as shown in FIG. 5A, the insulators 3 with metal bodies are disposed on both sides of the multilayer plate 14 that becomes the core material 13. At this time, the insulator 2 of each insulator 3 with a metal body is opposed to the multilayer board 14. The core material 13 is not particularly limited, but in the structure shown in FIG. 5, a three-layer plate is used, and the wiring pattern 12 of each conductor layer is conducted through the via hole 15. Needless to say, a printed wiring board as shown in FIG.

  Next, as shown in FIG. 5 (b), after heating and pressing to laminate and integrate, when the metal body 1 is peeled off as shown in FIG. 5 (c), the metal particles 5 are peeled off from the metal body 1. And remains in the insulator 2. At this time, the metal particles 5 are embedded in the surface layer portion of the insulator 2, and a part of each metal particle 5 is exposed on the surface of the insulator 2. And the metal film 8 is deposited thinly by performing electroless plating.

  Thereafter, as shown in FIG. 5 (d), after drilling is performed by laser processing, drilling, or the like, via holes are plated in the holes or the conductive paste 16 is filled, thereby forming via holes. 15 can be formed. When the conductive paste 16 is filled, the conductivity of the paste surface is ensured by polishing. A multilayer printed wiring board (five-layer board) as shown in FIG. 5E can be obtained by forming a pattern after electrolytic plating. A multilayer wiring board can also be manufactured using the wiring board thus obtained as the core material 13. In addition, the heat and pressure molding in the case where the insulator 3 with the metal body is laminated and integrated on the multilayer plate 14 is a condition in which the insulator 2 after molding is maintained in the B stage state or the insulator 2 is in the C stage state. Perform under conditions. In addition, electroplating may be performed subsequent to electroless plating before performing the above-described drilling by laser processing, drilling, or the like.

As mentioned above, metallic body with the insulator 3, additive plating insulator 6, additive plating metal coating with the substrate 9, a multilayer printed wiring board by a build-up method or the like to continue to laminating the conductive layer via the insulating layer In forming the conductor layer on the surface of the insulating layer by electroless plating and electrolytic plating, the surface roughness of the insulating layer can be reduced, and the insulating layer and By improving the adhesion with the conductor layer, it is possible to form a very fine wiring pattern 12 and to manufacture a wiring board with excellent electrical characteristics.

  Hereinafter, the present invention will be specifically described by way of examples.

Example 1
As the metal body 1, SUS301 (76% Fe, 17% Cr, 7% Ni), which is a stainless material 10, tempered 3 / 4H, and a thickness of 100 μm was used. And the roughened surface 4 is given to the said metal body 1 by performing the etching process for 60 second using the ferric chloride solution (redox potential 500mV, specific gravity 1.46) containing 10.0 mass% copper ion. Formed.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, the roughened surface 4 and the prepreg for FR-4 (thickness: 100 μm) (“R-1661” manufactured by Matsushita Electric Works Co., Ltd.) are opposed to each other. Then, after heat-pressing at 1.96 MPa (20 kg / cm ² ) at 160 ° C. for 60 minutes to form a laminate, the metal body 1 was peeled off (see FIGS. 1A to 1C). And after making the copper film 17 into a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed to grow the copper film 17 to a thickness of about 18 μm (FIG. 1 ( d)).

(Example 2)
The same metal body 1 as in Example 1 was used. And the roughened surface 4 is given to the said metal body 1 by performing the etching process for 30 second using the ferric chloride solution (Redox potential 500mV, specific gravity 1.46) containing 20.0 mass% copper ion. Formed.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, the roughened surface 4 and the thermosetting adhesive sheet (thickness 50 μm) (“R-0880” manufactured by Matsushita Electric Works Co., Ltd.) are opposed to each other. Then, after heat-pressing at 1.96 MPa (20 kg / cm ² ) at 160 ° C. for 60 minutes to form a laminate, the metal body 1 was peeled off (see FIGS. 1A to 1C). And after making the copper film 17 into a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed to grow the copper film 17 to a thickness of about 18 μm (FIG. 1 ( d)).

(Example 3)
The same metal body 1 as in Example 1 (however, the thickness was 50 μm) was used. In the same manner as in Example 1, the roughened surface 4 was formed on the metal body 1.

Next, a one-component thermosetting epoxy resin varnish is applied to the roughened surface 4 of the metal body 1 so as to have a thickness of 50 μm, and this is dried in an oven at 150 ° C. for 2 minutes, whereby B stage Insulator 3 with a metal body to which a resin in the form of a stick was attached. Thereafter, two insulators 3 with a metal body were prepared, and an FR-4 substrate on which a circuit was formed in advance was used as the core material 13, which was sandwiched with the insulator 3 with a metal body, and heated at 160 ° C. for 60 minutes. The laminate was formed by heating and pressing at 0.98 MPa (10 kg / cm ² ), and then the metal bodies 1 on both sides were peeled off (see FIGS. 5A to 5C). Then, after the copper film 17 was made to have a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed, and the copper film 17 was grown to a thickness of about 18 μm.

Example 4
The same metal body 1 as in Example 1 was used. And the roughened surface 4 is given to the said metal body 1 by performing the etching process for 45 second using the ferric chloride solution (redox potential 540mV, specific gravity 1.46) containing 10.0 mass% copper ion. Formed.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, the roughened surface 4 and the thermoplastic sheet (thickness 100 μm) (preparation for “R-4737” manufactured by Matsushita Electric Works Co., Ltd.) are opposed to each other. Then, after heating and pressing at 185 ° C. for 15 minutes at 0.49 MPa (5 kg / cm ² ) to form a laminate, the metal body 1 was peeled off (see FIGS. 1A to 1C). And after making the copper film 17 into a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed to grow the copper film 17 to a thickness of about 18 μm (FIG. 1 ( d)).

(Example 5)
The same metal body 1 as in Example 1 was used. Then, a roughened surface 4 is formed on the metal body 1 by performing an etching process for 45 seconds using a ferric chloride solution (oxidation-reduction potential 520 mV, specific gravity 1.45) containing 10 mass% nickel ions. did.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, the roughened surface 4 and the thermosetting adhesive sheet (thickness 50 μm) (“R-0880” manufactured by Matsushita Electric Works Co., Ltd.) are opposed to each other. Then, after heat-pressing at 1.96 MPa (20 kg / cm ² ) at 160 ° C. for 60 minutes to form a laminate, the metal body 1 was peeled off (see FIGS. 1A to 1C). And after making the copper film 17 into a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed to grow the copper film 17 to a thickness of about 18 μm (FIG. 1 ( d)).

(Example 6)
The same metal body 1 as in Example 1 was used, and the roughened surface 4 was formed on the metal body 1 in the same manner as in Example 1.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, an insulating substrate having low α characteristics formed by filling a thermosetting epoxy resin with 85% by mass of silica particles as a filler, and the rough surface After facing the chemical surface 4 and heating and pressing at 1.96 MPa (20 kg / cm ² ) at 160 ° C. for 60 minutes, the metal body 1 was peeled off (FIGS. 1A to 1C). )reference). And after making the copper film 17 into a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed to grow the copper film 17 to a thickness of about 18 μm (FIG. 1 ( d)).

(Comparative Example 1)
First, an unevenness of about 5 μm was formed by desmearing the surface of the FR-4 substrate by a general method. Next, a substrate with a copper film was obtained by sequentially performing electroless copper plating and electrolytic copper plating using a palladium catalyst by a general method.

(Comparative Example 2)
First, by applying a desmear treatment to a surface of an insulating substrate having a low α characteristic, which is formed by filling a thermosetting epoxy resin with 85% by mass of silica particles as a filler by a general method, unevenness of about 3 μm is formed. Had made. Next, a substrate with a copper film was obtained by sequentially performing electroless copper plating and electrolytic copper plating using a palladium catalyst by a general method.

(Comparative Example 3)
The same metal body 1 as in Example 1 was used. Then, the roughened surface 4 was formed on the metal body 1 by polishing with # 1500 sandpaper instead of performing the etching process.

After the roughened surface 4 of the metal body 1 is washed with water and degreased, the roughened surface 4 and the prepreg for FR-4 (thickness: 100 μm) (“R-1661” manufactured by Matsushita Electric Works Co., Ltd.) are opposed to each other. Then, after heating and pressing at 1.96 MPa (20 kg / cm ² ) for 60 minutes at 160 ° C. to form a laminate, the metal body 1 was peeled off. Then, after the copper film 17 was made to have a thickness of about 1 μm by electroless copper plating under general conditions, electrolytic copper plating was then performed, and the copper film 17 was grown to a thickness of about 18 μm.

(Evaluation test)
1. Surface roughness measurement Based on JIS B0601, cut-off value λ _c = 0.80 mm, measured using a stylus type small surface roughness measuring instrument (Handy Surf; model number “E-35A”; manufactured by Tokyo Seimitsu Co., Ltd.) The length L = λ _c × 5 = 4.0 mm, the roughened surface 4 of the metal body 1 of Examples 1 to 6, the resin surface of the substrate with the copper coating of Comparative Examples 1 and 2, the metal body 1 of Comparative Example 3 The surface roughness Ra of each roughened surface 4 was measured.

2. Peel strength evaluation When the copper film 17 of each of the substrates of Examples 1 to 6 and Comparative Examples 1 to 3 is cut with a 1 cm width with a cutter, the copper film 17 is peeled off by visual measurement of only the spring by a tensile tester. Peel strength was measured.

  The above results are shown in [Table 1] below.

An example of embodiment of this invention is shown and (a)-(e) is sectional drawing. 1A is an enlarged cross-sectional view showing a portion A in FIG. 1A, FIG. 1B is an enlarged cross-sectional view showing a portion B in FIG. 1B, and FIG. It is sectional drawing which expands and shows the C part in (). It shows a state where the metal film grows, and (a) to (c) are cross-sectional views. It is sectional drawing which expands and shows the E section in Fig.3 (a). The other example of embodiment of this invention is shown, (a)-(e) is sectional drawing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal body 2 Insulator 3 Insulator with metal body 4 Roughening surface 5 Metal particle 6 Insulator for additive plating 7 Roughening surface 8 Metal film 9 Substrate with additive plating metal film

Claims (11)

The roughened metal body surface by bonding a sheet-like insulator is formed with the metal body insulator, as the metal body, the metal ion the metal particles in the etching solution to the roughened surface formed with an etchant those deposited by precipitating as are used, together with the metal particles are embedded in the insulating body is formed by peeling the metal body of the metal body with the insulator, the metal as nuclei for plating An insulator for additive plating , wherein particles are embedded in a surface layer portion of the insulator, and a part of the metal particles are exposed on a surface of the insulator. The insulator for additive plating according to claim 1, wherein the ionization tendency of the metal particles is smaller than the ionization tendency of the metal body. The insulator for additive plating according to claim 1 or 2, wherein the metal body is an alloy containing iron. The insulator for additive plating according to any one of claims 1 to 3, wherein the metal body has a thickness of 20 to 150 µm. The additive plating insulator according to any one of claims 1 to 4, wherein a roughened surface is formed on a surface of the insulator. Additive plating insulator according to any one of claims 1 to 5 wherein the roughened surface of the insulator is characterized by comprising a following uneven 1μm in surface roughness Ra. The insulator for additive plating according to any one of claims 1 to 6 , wherein the insulator is made of a resin composition. The insulator for additive plating according to any one of claims 1 to 7 , wherein the insulator is made of a resin-impregnated base material. Additive plating insulator according to any one of claims 1 to 8 wherein the insulator is characterized in that it consists of having an adhesive property. The metal particles exposed to the surface of the additive plating insulator according to any one of claims 1 to 9 becomes a nucleus for the plating, the metal film is formed by formed by plating on the surface of the insulator A substrate with an additive-plated metal film. The substrate with an additive-plated metal film according to claim 10 , wherein the metal particles are a metal mainly composed of copper.

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