JP4161904B2 - Resin film with copper foil, resin sheet with copper foil, copper-clad laminate - Google Patents

Description

  The present invention relates to a resin film with copper foil, a resin sheet with copper foil, and a copper-clad laminate used as printed wiring materials.

  In general, printed wiring boards are made of copper cloth laminated on a prepreg prepared by impregnating a base material such as glass cloth with a thermosetting resin such as epoxy resin, and this is heated and pressurized to produce a copper-clad laminate. After processing through-holes and through-hole plating on this copper-clad laminate, the copper foil on the surface is etched to form a wiring pattern, and the patterned copper-clad laminate is then passed through a prepreg. It is manufactured by laminating with copper foil or another circuit board and heating and pressing to form a multilayer. As the copper foil used at this time, the surface on the side to be laminated is formed on a roughened surface, the anchor effect by the roughened surface is used to increase the adhesion of the circuit, and the reliability as a printed wiring board can be ensured. Has been made.

  Recently, with copper foil produced by applying an adhesive resin such as an epoxy resin to the roughened surface of the copper foil, and making the adhesive resin a semi-cured (B stage) insulating resin layer. A printed wiring board, particularly a multilayer printed wiring board, is manufactured by using a resin sheet and thermocompression bonding a resin sheet with a copper foil to a circuit board or the like on the insulating resin layer side.

  Here, recent various electronic components are highly integrated, and ICs and LSIs incorporating small and high-density circuits are used. Wiring patterns are also used on printed wiring boards on which these electronic components are mounted. There is a demand for higher density, and printed wiring boards with fine patterns with fine line widths and pitches between lines are required. For example, in the case of a printed wiring board used for a semiconductor package, a substrate having high-density ultrafine wiring with a line width and a line-to-line pitch of about 30 μm is also required. However, since the copper foils conventionally used as described above are thick, it is practical to form such a high-density wiring pattern with a fine line spacing and line width using the copper foil. Have difficulty.

  Therefore, as a copper foil capable of forming a high-density and fine wiring pattern, Patent Document 1 proposes the following ultrathin copper foil with an adhesive. That is, the ultrathin copper foil with an adhesive of Patent Document 1 is coated with a curable resin composition that is cured by heat or the like on a surface-treated ultrathin copper foil that is temporarily bonded to a carrier and has a thickness of 9 μm or less. It is made to be semi-cured into a state to function as an adhesive. Examples of the carrier include aluminum, copper, iron, and paper. And this copper foil is used in the form of forming the wiring pattern on the copper foil by exfoliating and removing the carrier after the thermocompression bonding of the adhesive side surface and the circuit board etc. It is what is done. In this case, since the copper foil is as thin as 9 μm or less, it is said that a fine wiring pattern can be formed.

  However, the ultrathin copper foil of Patent Document 1 has the following problems. For example, when the carrier is aluminum, it is necessary to use an alkali etchant such as sodium hydroxide when etching and peeling / removing the aluminum of the carrier after thermocompression bonding. This alkali etching requires a long time. Therefore, a significant increase in manufacturing cost is caused. If the carrier is copper, the carrier copper can be physically peeled after thermocompression bonding, but the copper is expensive and the ultra-thin copper foil is reliably left on the circuit board side. It is difficult to make it possible to peel only the carrier copper from the ultrathin copper foil in the state, and disposal of the carrier copper that has been peeled and removed also becomes a problem. Furthermore, when the carrier is iron, for example, the carrier iron may rust during storage, and when the carrier is paper, the paper is water permeable, so it is extremely important in the process before thermocompression bonding. When the thin copper foil is treated with various chemical solutions, there is a problem that the paper may be altered or the chemical solution may penetrate into the interface with the ultrathin copper foil and peel off.

On the other hand, a copper foil with a resin film using a resin film as a carrier instead of the metal or paper as described above has also been proposed (see Patent Document 2). By using a resin film as a carrier, the above-mentioned problem of Patent Document 1 can be solved. And the copper foil with a resin film of patent document 2 is formed by laminating the electroless copper plating layer and the electrolytic copper plating layer in this order on the surface of the resin film, and the electroless copper plating layer and the electrolytic copper plating. The copper foil which consists of a layer is formed in 1-7 micrometers ultra-thin.
Japanese Patent Laid-Open No. 10-146915 JP 2000-141542 A

  As described above, the copper foil with a resin film of Patent Document 2 is an unprecedented excellent copper foil, but the copper foil is composed of an electroless copper plating layer and an electrolytic copper plating layer. It has a problem that it can only be used in narrow applications.

  This invention is made | formed in view of said point, It aims at providing the resin film with a copper foil and resin sheet with a copper foil with high versatility, and these resin films with a copper foil. Another object of the present invention is to provide a copper-clad laminate using a resin sheet with copper foil.

The resin film with a copper foil according to claim 1 of the present invention roughens the surface of the resin film 1 to form an uneven surface, and the recessed portion 8 of the uneven surface is a recessed portion 8 viewed from the electroless plating layer 2 side. The depth-returned shadow portion is formed so that the area ratio is within 10% , and on the surface of the resin film 1, an electroless plating layer 2 made of a metal other than copper or a copper alloy and a copper single layer or a copper layer are formed. And an electroplating layer 3 composed of a plurality of layers mainly composed of the above, the electroless plating layer 2 is formed to have a thickness of 1 μm or less, and the surface of the electroplating layer 3 is formed on the roughened surface 4. It is characterized by.

  According to this invention, versatility can be improved by forming the electroless plating layer 2 from a metal other than copper or a copper alloy.

  The invention of claim 2 is characterized in that, in claim 1, the thickness of the electrolytic plating layer 3 is 0.5 to 105 μm.

  By forming the thickness of the electrolytic plating layer 3 to 0.5 μm or more, pinholes can be prevented from being generated in the electrolytic plating layer 3, and by forming the thickness of the electrolytic copper plating layer 3 to 105 μm or less. Further, it is possible to prevent peeling from the resin film 1 when the electrolytic plating layer 3 is bent.

  In the resin sheet with copper foil according to claim 3 of the present invention, the insulating resin layer 5 in the B stage state is formed on the roughened surface 4 of the electrolytic plating layer 3 of the resin film A with metal foil according to claim 1 or 2. It is characterized by being laminated.

  The resin sheet with copper foil formed in this way is laminated on a substrate or the like on the side of the insulating resin layer 5 and heated and pressed to laminate the copper foil 6 on the substrate or the like using the insulating resin layer 5 as an adhesive layer. Therefore, it is possible to easily produce a copper-clad laminate without using a prepreg or the like for laminate bonding.

  According to the present invention, since the electroless plating layer 2 is made of a metal other than copper or a copper alloy, versatility can be improved.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 shows an example of a resin film A with copper foil according to the present invention. By laminating an electroless plating layer 2 and an electrolytic plating layer 3 on one side of the resin film 1 in this order, the electroless plating layer 2 is formed. And a copper foil 6 made of the electrolytic plating layer 3 is provided on one surface of the resin film 1, and the surface of the electrolytic plating layer 3 is formed as the roughened surface 4.

  Here, as said resin film 1 used as the carrier of the copper foil 6, the flexible plastic film which can be bend | folded and deform | transforms comparatively easily with a physical force can be used. Specifically, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polyethylene and polypropylene, polyphenylene sulfide, polyimide, polyethylene naphthalate, polystyrene including syndiotactic polystyrene, polycarbonate, polyvinyl alcohol, polyvinyl chloride, polyvinyl chloride Examples thereof include various celluloses such as vinylidene, polyurethane and poly (cellulose acetate), polyamides such as (meth) acrylic resins and various nylons, and sheets of fluororesin. Of these, polyester is preferable, and polyethylene terephthalate is particularly preferable. Although the thickness of the resin film 1 is not specifically limited, About 5-250 micrometers is preferable, More preferably, it is about 20-100 micrometers.

  The resin film 1 may be either a simple substance or a composite. Moreover, a heat peelable film can also be used as the resin film 1. This heat-peelable film is sticky on the surface of the base resin film at room temperature, and when heated, it is coated with a heat-peelable adhesive that removes the stickiness, and a separator is applied to the surface of the heat-peelable pressure-sensitive adhesive layer. It is coated. Then, the separator is peeled off and a metal foil 6 is laminated and provided on the heat-peelable pressure-sensitive adhesive layer as described later. By using such a heat-peelable resin film as the resin film 1, the resin film 1 is formed from the metal foil 6 when the resin film A with metal foil, which will be described later, is heated and pressed to be laminated with a circuit board or the like. The operation of heat peeling and peeling off the resin film 1 is facilitated.

  It is preferable that at least the surface of the resin film 1 on the side where the electroless plating layer 2 is laminated is subjected to a treatment for improving the adhesion of the electroless plating layer 2 to the resin film 1. It is more preferable that the treatment for improving the adhesion is performed on both surfaces of the resin film 1.

  The process which improves the adhesiveness of the electroless-plating layer 2 with respect to the resin film 1 can be performed by roughening the surface of the resin film 1 and making it an uneven surface, for example. The roughening treatment can be performed by a conventional method, for example, a physical method such as a sand blasting method or a chemical erosion method, and the surface of the resin film 1 is filled with filler-containing paint or other paint. The surface can also be roughened by coating. By forming a rough surface by roughening in this way, the adhesion between the electroless plating layer 2 and the resin film 1 can be enhanced by the anchor effect by the uneven surface, and during the electroless plating process It is possible to prevent the plating film from being peeled off from the resin film 1 and to prevent the electroless plating layer 2 from being peeled off from the resin film 1 during the subsequent electrolytic plating process. A copper foil 6 composed of an electroless plating layer 2 and an electrolytic plating layer 3 can be laminated on the surface. Moreover, since the uneven surface is transferred to the surface of the copper foil 6 from which the resin film 1 has been peeled to become a rough surface, the adhesion between the copper foil 6 and the dry film in the circuit forming process is improved, and in particular, the direct copper foil. In the processed product that performs circuit formation in FIG. 6, if the resin has an appropriate rough surface as described above, the resin film 1 is peeled off and the dry film is laminated immediately, so that the yield of circuit formation can be achieved without a cleaning / polishing process. It will be possible to prevent problems.

Thus, when forming the surface of the resin film 1 in an uneven surface and improving adhesiveness, the adhesiveness of the electroless plating layer 2 with respect to the resin film 1 is improved by the surface roughness and roughening shape of the uneven surface of the resin film 1. It is possible to control, and after the copper foil 6 is laminated and bonded to a circuit board or the like, the peel strength can be set such that the resin film 1 can be appropriately peeled from the copper foil 6. For this purpose, the concave and convex portion 8 on the surface of the resin film 1 is formed such that the shadow portion of the depth return of the concave portion 8 viewed from the electroless plating layer 2 is within 10% in area ratio. you. As shown in FIGS. 6A and 6B, an undercut portion 9 is formed so that the depth of the recess 8 is wider than the width of the opening. If it is, it means the part of the undercut part 9, and the dent when the concave part 8 is cut in parallel with the surface of the resin film 1 at the deepest part of the undercut part 9 (range a in FIG. 6). The area (ab) of the difference between the area a in the portion 8 and the area b of the opening portion of the recessed portion 8 (the range of b in FIG. 6) from the area a is the area of the shadow portion. The [area (a-b) / area a] it is you to be within 10%. When the resin film 1 is peeled off from the copper foil 6 after the copper foil 6 is laminated and bonded to the circuit board or the like, the film resin is not left on the copper foil 6 side. It is important to prevent the residue, and when the shadow portion of the depth return of the recess 8 is larger than 10% in area ratio, the resin of the film is large when the resin film 1 is peeled from the electroless plating layer 2 of the copper foil 6 The resin may remain even if the copper foil 6 is polished in the circuit forming process.

  Moreover, the process which improves the adhesiveness of the electroless-plating layer 2 with respect to the resin film 1 can be performed also by processing the surface of the resin film 1 with a coupling agent, for example. That is, in order to perform electroless plating on the resin film 1, it is necessary to apply a catalyst that causes electroless plating to the surface of the resin film 1, but there is no catalyst adsorption ability such as a polyethylene terephthalate film or a polyimide film. In the case of the resin film 1, the catalyst is generally adsorbed by a chemical reaction after surface modification using a strong acid, strong alkali, strong reducing agent, or the like. On the other hand, the present inventors can immerse the coupling film in an aqueous solution of a coupling agent without washing the resin film 1, wash it with water, and immerse it in a catalyst solution. It was discovered that the ring agent adsorbs palladium tin colloid, which is a general electroless plating catalyst, and easily causes electroless plating.

Therefore, by treating the surface of the resin film 1 with a coupling agent, the electroless plating catalyst is firmly adsorbed on the surface of the resin film 1, and the electroless plating layer 2 and the resin film formed using this catalyst as a nucleus. 1 can be improved. When analysis is performed using an X-ray photoelectron analyzer, a coupling agent layer, for example, a Si layer in the case of a silane coupling agent, is detected between the resin film 1 treated with the coupling agent and the electroless plating layer 2. It is confirmed that the adhesion between the resin film 1 and the electroless plating layer 2 is enhanced by the coupling agent. A water-soluble silane coupling agent is effective as the coupling agent used in the present invention, and a water-soluble aminosilane coupling agent is particularly preferable. Examples of the water-soluble aminosilane coupling agent include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (amino) having a general formula represented by NH ₂ —R—Si (OR ′) _3. Illustrate ethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, etc. Can do. Among these, N-β (aminoethyl) γaminopropyltriethoxy (or methoxy) silane, which is stable from the hydrophilicity and hydrolyzability of the aqueous solution, is desirable. These silane coupling agents can usually be treated by making an aqueous solution having a concentration of 0.001 to 5% by mass and immersing the resin film 1 in the aqueous solution. Here, washing with water after the coupling agent treatment is an essential step. One of the reasons is to eliminate the unevenness of the treatment of the coupling agent. The main reason is that when the coupling agent is mixed into the palladium-tin colloidal solution of the electroless plating catalyst, the coupling agent reacts with the colloid. Since the palladium-tin colloid coagulates and precipitates and the catalyst adhesion action is lost, a water washing step is necessary to eliminate the introduction of the coupling agent.

  In addition to the above, as a method of imparting an electroless plating catalyst to the resin film 1 having no catalyst adsorbing ability, a method of adhering the electroless plating catalyst to the surface of the resin film 1, or electroless plating in the resin of the resin film 1 There are a method of mixing a catalyst, a method of forming a resin layer or an inorganic layer mixed with an electroless plating catalyst on the surface of the resin film 1, and the like. For example, after applying a solution of fine particles of palladium, gold, silver, copper or the like on the surface of the resin film 1 as an electroless plating catalyst and drying it, the electroless plating catalyst is heated by heating it above the softening point of the resin film 1. A resin layer mixed with an electroless plating catalyst can be adhered to the surface of the resin film 1 by coating the resin film surface with a resin material or an inorganic material blended such that these fine particles appear on the surface. An inorganic layer can be formed.

  After applying the electroless plating catalyst to the surface of the resin film 1 as described above, washing with water, further activating the catalyst with an accelerator, further washing with water, and placing the resin film 1 in the electroless plating bath. The electroless plating layer 2 can be laminated by forming an electroless plating film on the surface of the resin film 1 by a general electroless plating wet process. The electroless plating layer 2 is a layer formed in order to impart electroconductivity to the surface of the resin film 1 so that electrolytic plating can be performed. In the present invention, the thickness is set to 1 μm or less. It is. This is because even if the thickness of the electroless plating layer 2 is thicker than 1 μm, it is not only wasteful in terms of imparting conductivity, but also causes an increase in manufacturing cost. The thickness of the electroless plating layer 2 is preferably as long as the conductivity for electrolytic plating is ensured, and the lower limit is not particularly set, but practically about 0.02 μm is the lower limit.

  After the electroless plating layer 2 is formed on the surface of the resin film 1 in this way, the resin film 1 is immersed in an electrolytic plating solution and energized to the electroless plating layer 2, thereby electrolyzing the surface of the electroless plating layer 2. By depositing a plating film and laminating the electrolytic plating layer 3, a copper foil 6 composed of the electroless plating layer 2 and the electrolytic plating layer 3 can be formed. The thickness of the electrolytic plating layer 3 is preferably set in the range of 0.5 to 105 μm. When the electroplating layer 3 is a thin electroplating film having a thickness of less than 0.5 μm, a large number of pinholes are generated in the electroplating layer 3, and inconveniences such as disconnection are liable to occur when forming a wiring pattern. . If the thickness of the electrolytic plating layer 3 exceeds 105 μm, the electrolytic plating layer 3 may be peeled off from the resin film 1 when bent.

  Here, in the present invention, the electrolytic plating layer 3 which is the main body of the copper foil 6 is formed of copper, but in addition to being formed as a single layer of copper as shown in FIG. A plurality of layers mainly composed of a copper layer may be used. When the electrolytic plating layer 3 is formed of a plurality of layers made of a copper layer and a metal layer other than copper as shown in FIG. 1B, the layer 3a on the side in contact with the electroless plating layer 2 is nickel having a thickness of 1 μm or less. It is preferable that the layer 3b is made of a metal other than copper, such as zinc, chromium or cobalt, and the layer 3b opposite to the electroless plating layer 2 is formed of copper.

  The electroless plating layer 2 is formed of a metal other than copper or a copper alloy. The metal particles deposited as the electroless plating layer 2 are involved in the adhesive strength with the surface of the resin film 1, and the heating / pressing step when the copper foil 6 is laminated on a circuit board or the like; In order to prevent oxidation of the electrolytic plating layer 3 mainly composed of copper after peeling 1, the electroless plating layer 2 is formed of a metal other than copper or a copper alloy. As a metal other than copper forming the electroless plating layer 2, nickel, cobalt, zinc, zinc oxide and the like are preferable, and as the copper alloy, an alloy of these metals and copper is preferable. In particular, nickel or an alloy of copper and nickel is desirable because of its good adhesive force with the resin film 1. In addition to forming the electroless plating layer 2 as a single layer as shown in FIG. 1A, the electroless plating layer 2 may be formed as a plurality of layers as shown in FIG. When the electroless plating layer 2 is formed from a plurality of layers, each of the plurality of layers 2a and 2b is formed of a metal other than copper or a copper alloy. FIG. 1C shows an embodiment in which the electroless plating layer 2 is formed from a plurality of layers and the electrolytic plating layer 3 is formed of a single layer of copper.

  When the electroplating layer 3 is formed on the electroless plating layer 2 as described above, the surface of the electroplating layer 3 is formed on the roughened surface 4 by appropriately selecting the conditions of electroplating. be able to. Specifically, by changing the bath composition, bath temperature, current density, electrolysis time, etc. at the final stage when the electroplating layer 3 is formed, the surface of the already formed electroplating film is 0.2 to 0.2. Copper particles of about 2.0 μm can be deposited as protrusions, and the roughened surface 4 can be formed by unevenness due to the copper particles. When the surface of the electrolytic plating layer 3 is formed on the roughened surface 4 by such roughening treatment, when the copper foil 6 is laminated by thermocompression bonding to a circuit board or the like via a prepreg or the like, the bonding strength is obtained by the anchor effect. It can be obtained high.

  Although the resin film A with a copper foil obtained by laminating the copper foil 6 composed of the electroless plating layer 2 and the electrolytic plating layer 3 on the resin film 1 can be obtained as described above, the electrolytic plating layer 3 of FIG. It is preferable to further form a nickel layer 11 and a zinc layer 12 in this order on the roughened surface 4. When the zinc layer 12 is thermocompression bonded to the copper foil 6 and the circuit board using an adhesive such as a prepreg, the adhesive deteriorates due to the reaction between the copper of the electrolytic plating layer 3 and the adhesive, or the electrolytic plating. The surface of the layer 3 is prevented from being oxidized and functions to increase the bonding strength with the circuit board and the like, and the copper protrusion on the roughened surface 4 of the electrolytic plating layer 3 is an adhesive. When it bites into the copper, the copper in the protrusion can be easily removed by etching due to the action of zinc existing at the interface between the copper protrusion and the adhesive. The nickel layer 11 functions to prevent the zinc of the zinc layer 12 from thermally diffusing to the copper electroplating layer 3 side during the thermocompression bonding, thereby effectively exerting the above functions of the zinc layer 12.

Here, since zinc easily diffuses into copper, if the thickness of the zinc layer 12 is too thin, the amount of zinc present on the surface of the copper electroplating layer 3 is extremely reduced as a result of diffusion. The meaning of forming the zinc layer 12 disappears. If the thickness of the zinc layer 12 is increased, this problem will not occur. However, on the other hand, the amount of zinc eluted during etching increases and a clearance is generated between the roughened surface 4 of the electrolytic plating layer 3 and the adhesive layer. Also in this case, the bonding strength is reduced. For this reason, the thickness of the zinc layer 12 is preferably set in a range of 0.15~0.5mg / dm ^2.

On the other hand, the thickness of the nickel layer 11 that functions as a zinc diffusion preventing layer has a correlation with the thickness of the zinc layer 12. For example, when the thickness of the nickel layer 11 is thin, the function as a zinc diffusion preventing layer is not sufficiently exhibited. Therefore, when increasing the bonding strength between the electrolytic plating layer 3 and the adhesive, A relatively large amount of the nickel layer 11 needs to be present on the zinc layer 12 in view of the amount of zinc diffusion. When the thickness of the nickel layer 11 is made thinner than 0.01 mg / dm ² , the function as a zinc diffusion preventing layer is hardly exhibited, and when the thickness is 0.05 mg / dm ² or more, the nickel layer 11 is formed thereon. Even if the thickness of the zinc layer 12 is about 0.15 to 0.5 mg / dm ² , the zinc diffusion can be effectively prevented. However, if the thickness of the nickel layer 11 is greater than 0.05 mg / dm ² , the function of the zinc diffusion preventing layer is improved, but on the other hand, the nickel layer 11 inhibits etching. For this reason, the thickness of the nickel layer 11 is preferably set in the range of 0.01-0.05 mg / dm ^2.

  The nickel layer 11 and the zinc layer 12 can be formed by applying a known electrolytic plating method or electroless plating method. Moreover, said nickel layer 11 may be formed with pure nickel, and may be formed with phosphorus-containing nickel containing 6 mass% or less of phosphorus.

Further, when the chromate treatment is further performed on the surface of the copper foil 6, an antioxidant layer can be formed on the surface of the copper foil 6. The chromate treatment can be carried out by a known method, for example, the method disclosed in JP-A-60-86894, which is 0.01 to 0.2 mg / in terms of chromium. An excellent anticorrosive ability can be imparted to the copper foil 6 by adhering about dm ² of chromium oxide and its hydrate.

  Further, by performing further silane coupling treatment on the surface of the copper foil 6 thus chromated, a functional group having a strong affinity for the adhesive can be imparted to the surface of the copper foil 6. The bonding strength with the circuit board and the like can be further improved, and the rust prevention and heat resistance of the copper foil 6 can be improved. Examples of the silane coupling agent used in this case include vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3- Examples thereof include aminopropyltriethoxysilane. Silane coupling treatment can be carried out by making these silane coupling agents into an aqueous solution having a concentration of 0.001 to 5% by mass, applying this to the surface of the copper foil 6 and then drying by heating. In addition, it can replace with a silane coupling agent, and the same effect can be acquired even if it carries out a coupling process using coupling agents, such as a titanium type and a zircon type.

  The resin film A with copper foil of FIG. 1 and FIG. 2 produced as described above can be used for producing a copper-clad laminate C, and the copper-clad laminate C is used. A printed wiring board such as a multilayer printed wiring board can be manufactured. For example, by superposing a resin film A with a copper foil on an adhesive material such as a prepreg on the side of the copper foil 6 on a substrate 14 such as a circuit board having a wiring pattern formed on the surface, and heating and press-molding this, A copper-clad laminate C in which the copper foil 6 is laminated and bonded to the substrate 14 with the insulating adhesive layer 16 made of an adhesive material as shown in FIG. And after peeling the resin film 1 from the copper foil 6 and exposing the copper foil 6 as shown in FIG. 3B, after processing the via hole and plating in the via hole as necessary, The printed wiring board D can be manufactured by etching the copper foil 6 to form the wiring pattern 15 as shown in FIG. The copper foil 6 can be used in the configuration in which the electroless plating layer 2 and the electrolytic plating layer 3 are laminated to form the wiring pattern 15, and the electroless plating layer 2 is peeled off from the electrolytic plating layer 3 together with the resin film 1. Thus, the wiring pattern 15 can be formed using the electrolytic plating layer 3 as the copper foil 6. In FIG. 3 (and FIGS. 4 and 5 described later), the nickel layer 11 and the zinc layer 12 are not shown. In addition, a single-sided copper-clad laminate can also be produced by stacking the resin film A with copper foil on one side or a plurality of prepregs on the copper foil 6 side, and heating and pressing the same. .

  Here, in the resin film A with copper foil, since the copper foil 6 is formed by plating on the surface of the resin film 1, it can be formed very thin, and the fine wiring pattern 15 It can be formed. Even if the copper foil 6 is extremely thin, it is reinforced with the resin film 1 rich in flexibility, so that the copper foil 6 is not wrinkled or broken during handling.

  Next, FIG. 4 shows an example of the resin sheet B with copper foil according to the present invention, and the roughened surface 4 of the copper foil 6 of the resin sheet A with copper foil produced as described above is made of an adhesive resin. A resin sheet B with a copper foil is formed by covering and laminating the insulating resin layer 5 that is covered and made of a thermosetting resin for adhesion in a B-stage state. Here, the B-stage state means that the thermosetting resin is in a semi-cured state, and even if the surface is touched with a finger, there is no sticky feeling and the insulating resin layer 5 can be stored in an overlapping manner, and heat treatment is performed. This means a state in which a curing reaction occurs in the thermosetting resin.

  Although it does not specifically limit as thermosetting resin which forms said insulating resin layer 5, For example, an epoxy resin, a polyimide resin, a polyfunctional cyanate ester compound etc. can be mentioned as a suitable thing. . In particular, the following resin composition is suitable because it can simultaneously improve the heat resistance and flame retardancy of the resin sheet B with copper foil.

  It is a resin composition containing a polyfunctional cyanate ester compound and a brominated epoxy compound, and has a glass transition temperature of 180 ° C. or higher after thermocompression bonding to a circuit board substrate or the like. The reason why the glass transition temperature is preferably 180 ° C. or higher is that a large temperature rise occurred, for example, when passing through a reflow furnace in the process of manufacturing a printed wiring board with high density mounting using the resin sheet B with copper foil. This is because the resin composition is not thermally deteriorated by these temperature rises when the temperature rises greatly during actual use.

As the polyfunctional cyanate ester compound, those disclosed in JP-A-10-146915 can be used. In this case, when the content of the polyfunctional cyanate ester compound is less than 50% by mass, the heat resistance of the insulating resin layer 5 is lowered, and when the content is more than 70% by mass, the manufactured copper foil Since the adhesiveness when the resin sheet B with adhesive is thermocompression bonded to a circuit board or the like under standard hot pressure conditions of, for example, a temperature of 170 ° C. and a pressure of 4.9 MPa (50 kg / cm ² ) for 60 minutes, the resin composition The content of the polyfunctional cyanate ester compound in the product is preferably set to 50 to 70% by mass.

  The brominated epoxy compound is a component blended in order to make the insulating resin layer 5 flame-retardant and to increase its heat resistance. Examples of brominated epoxy compounds having such a function include “Epicoat 5050” (bromine content 47 to 51 mass%) manufactured by Yuka Shell Epoxy Co., Ltd. and “Araldite 8018” manufactured by Asahi Ciba Co., Ltd. And so on. The amount of the brominated epoxy compound is preferably set to 12 to 20% by mass in terms of bromine. When the blending amount is less than 12% by mass, the flame retardant standard UL-94V0 cannot be satisfied, and when it exceeds 20% by mass, the obtained resin sheet B with copper foil is heated to a circuit board or the like. The flexibility at the time of pressure bonding is deteriorated, and there is a possibility that powder blowing increases when the printed wiring board manufactured using the resin sheet B with copper foil is cut.

  In the case of a resin composition in which the content of the polyfunctional cyanate ester compound and brominated epoxy resin is the above-described values, the insulating resin obtained is obtained by applying the above standard hot pressure conditions during thermocompression bonding. The glass transition temperature of the layer 5 shows a value of 180 ° C. or higher. In addition, when antimony oxide is blended with a brominated epoxy compound, the amount of brominated epoxy compound can be reduced. For example, when about 2 mass% of antimony oxide is blended, the amount of brominated epoxy compound is blended. Is about 10% by mass, the UL standard can be satisfied.

  When the insulating resin layer 5 is formed, the above-described resin or resin composition is dissolved in a solvent such as methyl ethyl ketone (MEK) or toluene to form a resin liquid, and this resin liquid is used as the copper foil 6 of the resin film A with copper foil 6. After the coating on the roughened surface 4 by a roll coater method or the like, it can be carried out by heating and drying to remove the solvent to obtain a B-stage state. For example, a hot air drying furnace can be used for drying, and the drying temperature is preferably 100 to 200 ° C, more preferably 130 to 170 ° C.

  The resin sheet B with copper foil produced as described above can be used for producing a copper-clad laminate C, and a multilayer printed wiring board or the like using the copper-clad laminate C can be used. A printed wiring board can be manufactured. That is, first, the insulating resin layer 5 is superposed on a substrate 14 such as a circuit board, and then the whole is heated and pressed to thermally cure the insulating resin layer 5, so that the insulating adhesive layer 16 made of the insulating resin layer 5 forms a copper foil. A copper-clad laminate C in which 6 is laminated and bonded to the substrate 14 as shown in FIG. 5A can be produced. Then, the resin film 1 is peeled to expose the copper foil 6 as shown in FIG. 5B, and the copper foil 6 is etched to form a predetermined wiring pattern 15 as shown in FIG. 5C. Thus, a printed wiring board can be manufactured. The copper foil 6 can be used in the configuration in which the electroless plating layer 2 and the electroplating layer 3 are laminated, and the wiring pattern 15 can be formed. In addition, the electroless plating layer 2 is peeled from the electroplating layer 3 and electroplated. The wiring pattern 15 can be formed using the layer 3 as the copper foil 6. Moreover, a single-sided copper-clad laminate can also be produced by heating and press-molding a single resin sheet B with copper foil.

  Thus, since the resin sheet B with copper foil can be laminated and bonded to the substrate 14 with the insulating resin layer 5, a multilayer printed wiring board can be produced without the need to use a prepreg. Since the prepreg is made of a substrate such as glass cloth, the prepreg has a predetermined thickness. However, the insulating resin layer 5 can be formed thin as long as adhesion and interlayer insulation are ensured. An extremely thin multilayer printed wiring board having a thickness of 100 μm or less can be produced. The thickness of the insulating resin layer 5 is preferably 20 to 80 μm. When the thickness of the insulating resin layer 5 is less than 20 μm, the adhesive force is lowered and it is difficult to ensure interlayer insulation. On the contrary, if the thickness of the insulating resin layer 5 exceeds 80 μm, it becomes difficult to produce a very thin multilayer printed wiring board, and the flexibility of the formed insulating resin layer 5 is reduced, and cracks are caused during handling. Is likely to occur.

  Next, the present invention will be specifically described with reference to examples.

( Reference Example 1)
As the resin film 1, a polyphenylene sulfide (PPS) film having a size of 400 mm × 400 mm × thickness 50 μm was used.

And the catalyst for electroless-plating was provided by immersing the resin film 1 for 5 minutes in the palladium-tin colloid type "AT-105 activating liquid" made by Uemura Kogyo Co., Ltd. at 25 degreeC. Next, after washing this with water, the resin film 1 was immersed in “Sulcup AL-106 Accelerator” manufactured by Uemura Kogyo Co., Ltd. for 3 minutes at 25 ° C., and subjected to acceleration treatment. Next, after washing with water, the resin film 1 is placed on an electroless nickel plating solution “Nimden LPX” manufactured by Uemura Kogyo Co., Ltd. for 1 minute under the conditions of 90 ° C., bath load 0.8 dm ² / L, and deposition rate 8 μm / hr. By swinging and dipping, an electroless nickel plating film having a gloss thickness of 0.15 μm was uniformly deposited on both surfaces of the surface of the resin film 1 to form an electroless plating layer 2 on the resin film 1.

Next, one surface of the electroless nickel electroless plating layer 2 is sealed so that only one surface is immersed in the electrolytic copper plating solution, and the other surface of the electroless plating layer 2 is energized with copper under the following conditions. The copper electroplating layer 3 having a thickness of 6 μm is laminated on the surface of the electroless nickel electroless plating layer 2, and the copper foil 6 composed of the electroless plating layer 2 and the electroplating layer 3 is applied to the resin film 1. Formed on one side. Note that the current density was increased gradually to 50A / dm ^2.

Bath composition: metal copper 55 g / L, sulfuric acid 55 g / L, chloride ion 30 ppm (as NaCl), sodium 3-mercapto-1-propanesulfonate 1.5 ppm, hydroxyethyl cellulose 10 ppm, bath temperature: 58 ° C., counter electrode: included Phosphor copper plate, current density: 50 A / dm ² .

The surface roughness of the copper electroplating layer 3 obtained in this way was measured by the method specified in JIS B0601, and the 10-point average surface roughness (Rz) was 1.0 μm. The surface of the copper electroplating layer 3 was further subjected to the following copper plating to form a roughened surface 4. First, an electrodeposition bath having a composition composed of metallic copper: 20 g / L and sulfuric acid: 100 g / L was constructed. This is designated as bath (1). Further, an electrodeposition bath composed of metallic copper: 60 g / L and sulfuric acid: 100 g / L was constructed. This is called bath (2). The copper electroplating layer 3 was subjected to a roughening treatment for 5 seconds using a bath (1) under conditions of a bath temperature of 25 ° C. and a current density of 30 A / dm ² , thereby depositing copper particles on the surface. . Next, using the bath (2), a plating process is performed for 10 seconds under the conditions of a bath temperature of 60 ° C. and a current density of 15 A / dm ² , thereby providing a dense copper capsule plating layer covering the copper particles. Chemical surface 4 was formed.

  Thus, the resin film A with a copper foil as shown in FIG. At this time, when the surface of the copper electroplating layer 3 was observed with a microscope, it was a roughened surface 4 in which fine-particle projections were formed on the entire surface. The maximum particle diameter of the protrusions was 1.9 μm, the minimum value was 0.3 μm, and the Rz value was 3.4 μm. Next, a nickel layer 11 and a galvanized layer 12 were formed on the roughened surface 4 as follows.

First, a nickel plating bath having a composition of nickel sulfate hexahydrate 240 g / L, nickel chloride hexahydrate 45 g / L, boric acid 30 g / L, sodium hypophosphite 5 g / L was constructed, and zinc sulfate heptahydrate A galvanizing bath having a composition of 24 g / L of salt and 85 g / L of sodium hydroxide was constructed. Then, on the roughened surface 4 of the resin film A with copper foil, a stainless steel plate is used as the counter electrode, and nickel plating is performed for 1 second under conditions of a nickel plating bath temperature of 50 ° C. and a current density of 0.5 A / dm ^2. Further, a phosphorous nickel-containing layer 11 having a thickness of about 0.02 mg / dm ² is formed on the roughened surface 4, and a stainless steel plate is used as the counter electrode, the bath temperature of the galvanizing bath is 25 ° C., and the current density is 0.4 A / dm. 2 seconds ² conditions, subjected to zinc plating, thickness to form a zinc layer 12 of about 0.20 mg / dm ^2, to obtain a copper foil resin film a as shown in FIG.

  Next, this resin film A with copper foil was washed with water, and then chromate treatment was performed by immersing in a sodium hydroxide aqueous solution (liquid temperature: 55 ° C.) of chromium trioxide 3 g / L, pH 11.5 for 6 seconds. did. Further, the resin film with copper foil A, vinyltris (2-methoxyethoxy) silane was immersed in an aqueous solution of 2 g / L for 5 seconds, and then taken out, dried with hot air at a temperature of 100 ° C., and treated with a silane coupling agent.

The resin film A with copper foil thus obtained was cut into a length of 300 mm × width of 300 mm, and the surface on the side of the zinc layer 12 was a glass fiber cloth base epoxy resin prepreg sheet (FR-4) having a thickness of 1 mm. Placed on top of each other, sandwiched between two smooth stainless steel plates, and hot pressed under conditions of a temperature of 170 ° C., a pressure of 50 kg / cm ² , and a time of 60 minutes, to produce a single-sided copper-clad laminate having a thickness of 1 mm. . The copper foil 6 of the copper-clad laminate was covered with the resin film 1, but the resin film 1 could be peeled off with a slight force. The surface of the electroless plating layer 2 that appears when the resin film 1 is peeled off is Rz = 0.1 μm and is a mirror surface. And when the dry film ("DuPont" SP-100 ": 25 micrometers in thickness) is laminated on the surface of this electroless-plating layer 2 exposed with a 100 degreeC heating roll, since it peels easily, an electroless-plating layer The surface of No. 2 was subjected to buffing polishing with a brushing buff with a wet abrasive to laminate the dry film with a surface roughness of Rz = 1.0 μm.

  With respect to the copper foil 6 on the surface of the single-sided copper-clad laminate produced as described above, etching characteristics, bonding strength with a prepreg material, and hydrochloric acid resistance were measured according to the following specifications.

  Etching characteristics: The above dry film having a thickness of 25 μm was laminated on a single-sided copper-clad laminate as described above, and 100 linear parallel patterns having a line width of 35 μm, a line pitch of 25 μm, and a length of 30 mm were drawn and developed. Next, an etching process was performed by spraying an etchant composed of ferric chloride 2.0 mol / L and hydrochloric acid 0.4 mol / L to form a wiring pattern. In addition, the etching time to a laminated board performed the preliminary test using the same laminated board, investigated the optimal time until a copper residue was not recognized by the base of a wiring pattern, and employ | adopted the time. When the obtained wiring pattern was observed with a microscope for the presence or absence of a short portion and a cut portion, none was present, and the etching characteristics were good.

  Bonding strength: A sample was cut out from a single-sided copper-clad laminate, plated with copper so that the total thickness of the plating layer was 18 μm, and the peeling strength of the sample was determined in accordance with the method specified in JISC6511. It was measured. In addition, the thing whose value is 7.8 N / cm (0.8 kg / cm) or more is determined as a non-defective product. As a result of the measurement, the peel strength was 14.7 N / cm (1.5 kg / cm), indicating good bonding strength.

  Hydrochloric acid resistance: A sample on which a wiring pattern having a line width of 1 mm was immersed in hydrochloric acid (temperature: 25 ° C.) having a concentration of 12% by mass for 30 minutes, then taken out, measured for the above peeling strength, and peeled off before and after immersion in hydrochloric acid. The strength reduction rate (%) was calculated. The smaller this value, the better the hydrochloric acid resistance. As a result of the measurement, the rate of decrease in peel strength was 1.0%, indicating good hydrochloric acid resistance.

( Reference Example 2)
130 parts by weight of bisphenol A type epoxy resin “Epiclon 1121-75M” manufactured by Dainippon Ink & Chemicals, Inc., 2.1 parts by weight of dicyandiamide, 0.1 part by weight of 2-ethyl-4-methylimidazole, and methyl A thermosetting resin varnish was prepared by mixing 20 parts by weight of cellosolve.

And this thermosetting resin varnish was apply | coated to the surface of the copper foil 6 of the resin film A with a copper foil of the reference example 1 which the silane coupling agent process was complete | finished so that it might become thickness 6.0mg / dm < ² > with a roll coater. A resin sheet B with a copper foil as shown in FIG. 4A was prepared by forming a B-stage insulating resin layer 5 by heat treatment at a temperature of 160 ° C. for 5 minutes.

Using this resin sheet B with copper foil, a single-sided copper-clad laminate was produced in the same manner as in Reference Example 1, and the etching characteristics, peel strength, and hydrochloric acid resistance were measured in the same manner as described above. As a result, the etching characteristics are good with no short part and no cut part, the peel strength is good at 14.7 N / cm (1.5 kg / cm), and the hydrochloric acid resistance has a decrease rate of the peel strength of 1.0. %.

(Example 1 )
As the resin film 1, a polyethylene naphthalate (PEN) film having a size of 400 mm × 400 mm × thickness 50 μm was used.

  Then, the surface of the resin film 1 is subjected to sandblasting using abrasive grain alumina # 800 with a dry sandblasting apparatus one side at a time, and the pressure and shot time are adjusted so that Ra = 0.15 μm to roughen both surfaces. Made it. This surface was observed with a 1000 × electron microscope, and the area ratio of the shaded portion of the undercut portion 9 hidden in the resin recess 8 was measured to be 5%.

  Next, this resin film 1 was immersed in a palladium-tin colloid type “AT-105 activating solution” manufactured by Uemura Kogyo Co., Ltd. at 25 ° C. for 5 minutes to give a catalyst, washed with water, and then manufactured by Uemura Kogyo Co., Ltd. Using “Sulcup AL-106 Accelerator”, an acceleration treatment was performed at 25 ° C. for 3 minutes and washed with water. After performing the wet electroless plating pretreatment in this manner, copper sulfate 0.01 mol / L, nickel sulfate 0.05 mol / L, sodium hypophosphite 0.3 mol / L, sodium citrate 0.2 Using an electroless plating bath having a composition of mol / L, borax 0.05 mol / L, stabilizer 5 ppm, and pH 9.0, electroless plating was performed for 4 minutes under plating conditions of 60 ° C. and stirring. As a result, an electroless plating layer 2 made of a copper alloy of 42% by mass copper, 52% by mass nickel, and 6% phosphorus was formed on the surface of the resin film 1 with a thickness of 0.4 μm. The appearance of the electroless plating layer 2 was uniform and non-uniform, and was matte.

Thereafter, electrolytic copper plating is performed in the same manner as in Reference Example 1, a 6 μm thick copper electroplating layer 3 is laminated on the surface of the copper alloy electroless plating layer 2, and the electroless plating layer 2 and the electroplating layer 3. A resin film A with a copper foil in which a copper foil 6 made of the above was formed on one side of a resin film 1 was produced. Here, the in-plane variation of the 6 μm thick copper electroplating layer 3 was ± 0.3 μm.

In addition, using this resin film A with copper foil, a copper-clad laminate was prepared in the same manner as in Reference Example 1, and the electroless plating layer 2 of the copper foil 6 after peeling the resin film 1 from the copper foil 6 was obtained. The surface had Rz = 1.5 μm, and the peel strength of the resin film 1 was 1.5 N / cm (0.15 kg / cm), and there was no problem in peelability. Moreover, even if the surface which peeled the resin film 1 of the copper foil 6 was observed with a 1000 times electron microscope, adhesion of resin was not seen. Furthermore, even when a dry film was laminated on the surface of the copper foil 6 of this copper-clad laminate with a laminator and a pattern for etching characteristics was exposed and developed in the same manner as in Reference Example 1, the laminate film did not peel off.

In the same manner as in Reference Example 1, etching characteristics, peel strength, and hydrochloric acid resistance were measured. As a result, the etching characteristics are good with no short part and no cut part, the peel strength is good at 14.7 N / cm (1.5 kg / cm), and the hydrochloric acid resistance has a decrease rate of the peel strength of 1.0. %.

( Reference Example 3 )
As the resin film 1, a 400 mm × 400 mm × 50 μm thick heat peelable film (“Riva Alpha” manufactured by Nitto Denko Co., Ltd .: 150 ° C. peeled product, a type with a separator on one side) is removed and used. Each surface was sandblasted with abrasive alumina # 2000 using a dry sandblasting apparatus, and both surfaces were roughened by adjusting the pressure and shot time so that Ra = 0.05 μm.

And by performing electroless plating in the same manner as in Example 1, an electroless plating layer 2 of a copper alloy with laminated at a thickness of 0.4μm on the surface of the resin film 1, a 6μm thick in the same manner as in Example 1 Copper By laminating the electrolytic plating layer 3, a resin film A with a copper foil in which the copper foil 6 composed of the electroless plating layer 2 and the electrolytic plating layer 3 was laminated on one surface of the resin film 1 was produced.

Using this resin film A with copper foil, as in Reference Example 1, the whole was sandwiched between two smooth stainless steel plates, under conditions of a temperature of 170 ° C., a pressure of 4.9 MPa (50 kg / cm ² ), and a time of 60 minutes. A single-sided copper-clad laminate with a thickness of 1 mm was manufactured by hot pressing. In this case, the resin film 1 made of a heat-peelable film after the heat and pressure molding was peeled off from the copper foil 6, and a thin foil copper-clad laminate could be obtained simply by removing the resin film 1.

The resin film with a copper foil which concerns on this invention is shown, (a), (b), (c) is a schematic sectional drawing which shows each embodiment, respectively. It is a general | schematic expanded sectional view which shows other embodiment of the resin film with a copper foil which concerns on this invention. (A) is a schematic sectional drawing which shows embodiment of the copper clad laminated board which concerns on this invention, (b), (c) is sectional drawing which shows the process of manufacturing a printed wiring board. The resin sheet with copper foil which concerns on this invention is shown, (a), (b), (c) is a schematic sectional drawing which shows each embodiment. (A) is a schematic sectional drawing which shows embodiment of the copper clad laminated board which concerns on this invention, (b), (c) is sectional drawing which shows the process of manufacturing a printed wiring board. It is for demonstrating the shadow part of the depth return of a dent part, (a) is an expanded sectional view, (b) is an enlarged plan view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin film 2 Electroless plating layer 3 Electrolytic plating layer 4 Roughening surface 5 Insulating resin layer 6 Copper foil

Claims (4)

The surface of the resin film is roughened to have an uneven surface, and the concave portion of the uneven surface is formed so that the shadowed portion of the depth return of the concave portion viewed from the electroless plating layer side is within 10% in area ratio. In addition, an electroless plating layer made of a metal other than copper or a copper alloy and an electroplating layer consisting of a single layer of copper or a plurality of layers mainly composed of a copper layer are laminated in this order on the surface of the resin film, and electroless plating is performed. A resin film with copper foil, wherein the thickness of the layer is 1 μm or less and the surface of the electrolytic plating layer is formed on a roughened surface.   The resin film with copper foil according to claim 1, wherein the thickness of the electrolytic plating layer is 0.5 to 105 μm.   A resin sheet with copper foil, wherein the resin film with copper foil according to claim 1 or 2 is formed by laminating an insulating resin layer in a B-stage state on a roughened surface of an electrolytic plating layer.   A copper-clad laminate comprising the resin film with copper foil according to claim 1 or 2 or the resin sheet with copper foil according to claim 3.

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