JP4626225B2 - Copper-clad laminate for multilayer printed wiring board, multilayer printed wiring board, and method for producing multilayer printed wiring board - Google Patents

Description

  The present invention relates to a copper-clad laminate for a multilayer printed wiring board, a multilayer printed wiring board, and a method for producing a multilayer printed wiring board, and more particularly, a multilayer effective for producing a multilayer printed wiring board having an interstitial via hole structure. The present invention relates to a copper-clad laminate for a printed wiring board, a multilayer printed wiring board produced using the copper-clad laminate for a multilayer printed wiring board, and a method for producing the same.

  In recent years, with the increase in performance and miniaturization of electronic devices, wiring boards have been required to have a high multi-layer and high density. ) Is getting attention.

  The multilayer printed wiring board for performing interlayer connection by IVH has been conventionally known for its usefulness as disclosed in Patent Document 1, but with the progress of recent laser processing technology and paste printing technology, As a result, it has become possible to form IVH using technology, and various improved methods for manufacturing multilayer wiring boards have been proposed as disclosed in Patent Document 2, Patent Document 3, and the like.

  In particular, in the case of an all-layer IVH substrate by the method of Patent Document 3, the number of presses during lamination can be greatly reduced, and the manufacturing process has been refined. In this construction method, first, an insulating hard substrate 103 having a metal foil 102 as shown in FIG. Next, the metal foil 102 is etched to form a circuit 107 as shown in FIG. Next, as shown in FIG. 5C, an adhesive resin layer 104 is formed on the surface opposite to the circuit 107 of the insulating hard substrate 103 on which the circuit 107 is formed.

  Next, as shown in FIG. 5D, a hole 108 that penetrates the adhesive resin layer 104 and the insulating hard substrate 103 in the thickness direction and contacts the circuit 107 is formed. Next, as shown in FIG. 5 (e), a conductive paste 109 is filled into the hole 108 to produce a single-sided circuit board 111a in which the electronic circuit is conductive in the vertical direction.

  Here, when filling the hole 108 with the conductive paste 109, a protective film is formed around the hole 108. The protective film can be formed by laminating on the surface of the adhesive resin layer 104 and punching together at the time of drilling. Then, after filling the hole 108 with the conductive paste 109, the protective film is peeled off, so that the conductive paste 109 protrudes from the adhesive resin layer 104 by the thickness of the protective film to form a so-called conductive bump. be able to.

Similarly, single-sided circuit boards 111b, 111c, and 111d as shown in FIG. 6 are manufactured. Next, as shown in FIG. 6, single-sided circuit boards 111a, 111b, 111c, and 111d are laminated at once, and are heated and pressed to be integrated using a heating press to form an all-layer IVH multilayer board 112 shown in FIG. Can be obtained efficiently.
Japanese Patent Publication No. 45-13303 JP-A-8-255982 JP-A-9-36551

  However, when the conductive bump composed of the conductive paste 109 is heated and pressed simultaneously with the adhesive resin layer 104 using the above-described method, the conductive bump to be a via hole is formed with the adhesive resin layer 104 as shown in FIG. At the same time, it was swept away and deformed.

  In order to prevent such deformation of the conductive bumps, it is effective to suppress the deformation during pressing by increasing the strength of the conductive paste, and in general, heat treatment is performed before the heating press. Thus, a method is adopted in which the volatile component is evaporated to increase the viscosity of the conductive paste, and the thermosetting resin contained in the conductive paste is semi-cured to increase the viscosity. Such curing conditions vary depending on the type of conductive paste, but generally, heat treatment is performed at 50 to 100 ° C. for several tens of minutes.

  On the other hand, a circuit used as an inner layer circuit of a multilayer substrate usually has a height of 12 to 35 μm, and the adhesive resin layer is heated even after receiving a thermal history in the heat treatment process of this conductive paste. It is necessary to maintain a melt viscosity that is low enough to fill the space between the circuits during pressing.

  In general, adhesive resin filled between circuits melts when heated, and the viscosity decreases once. In the hot press process, the adhesive resin is applied all over the circuit by pressing in a vacuum atmosphere at this timing. Is designed to be filled. Here, if the viscosity is too high, the space between the circuits cannot be sufficiently filled at the time of hot pressing, or conversely, if the viscosity is too low, the cured state of the adhesive resin layer becomes unstable, and the hardening called winkle after the hot pressing Wrinkles are generated and sufficient performance as a printed wiring board cannot be maintained.

  For this reason, the adhesive resin layer does not become too high in viscosity even after receiving a heat history in the heat treatment step of the conductive paste, and is filled between circuits when performing hot pressing. However, it is necessary to maintain a possible viscosity.

  The present invention has been made to remedy the above-mentioned problems. The object of the present invention is to heat and heat a plurality of single-sided circuit boards each having an adhesive resin layer by using a heating press. In the case of manufacturing a multilayer printed wiring board having an IVH structure through a step of pressing and integrating, the strength of the conductive bump made of the conductive paste is increased by performing a heat treatment in advance before the heating press step, Even after receiving the heat history in the heat treatment process, the adhesive resin layer can maintain a low melt viscosity, and as a result, the shape of the via hole can be maintained with high accuracy and the resin can be satisfactorily filled between the circuits. An object of the present invention is to provide a copper-clad laminate for a multilayer printed wiring board.

  Another object of the present invention is to provide a multilayer printed wiring board excellent in insulation and a method for producing the same by being manufactured using the above-described copper-clad laminate for multilayer printed wiring board.

In order to solve the above problems, in the copper-clad laminate for multilayer printed wiring board according to claim 1 of the present invention, the copper foil and the thermosetting resin are cured and formed at a temperature of 100C to 400C. A copper-clad laminate for multilayer printed wiring boards in which a hard insulating layer that does not soften in a range, an adhesive resin layer that can be temporarily melted in the above temperature range, and a protective film are arranged and integrated in this order. The adhesive resin layer is prepared by mixing dicyandiamide used as a curing agent for epoxy resin in dimethylformamide in a thermosetting resin mainly composed of epoxy resin, and measuring melt viscosity. The ratio of the minimum melt viscosity (A) after the heat treatment at 100 ° C. for 90 minutes and the minimum melt viscosity (B) before the heat treatment measured at 4 ° C./min. Formula (a),
1 ≦ (A / B) ≦ 10 (a)
It is characterized by satisfying.

In the copper-clad laminate for a multilayer printed wiring board according to claim 2 of the present invention, the hard insulating layer of claim 1 is reinforced by an inorganic woven fabric, an inorganic nonwoven fabric, an organic woven fabric, or an organic nonwoven fabric. It is characterized by that.

A multilayer printed wiring board characterized by being manufactured using a plurality of copper-clad laminates for multilayer printed wiring boards according to claim 1 or 2 .

In the manufacturing method of the multilayer printed wiring board which concerns on Claim 4 of this invention, a circuit is formed in the copper foil surface of the copper clad laminated board for multilayer printed wiring boards in any one of (1) Claim 1,2. A step, (2) a step of forming a bottomed hole in contact with the circuit through the protective film, the adhesive resin layer and the hard insulating layer by punching from the protective film surface side; (3) heat in the bottomed hole A step of printing and filling a conductive paste using a curable resin as a binder resin to impart conductivity to the bottomed hole, (4) a state in which the protective film is peeled off and the leading end of the conductive paste is protruded A step of producing a single-sided circuit board in which the conductive paste front end portion is preferentially cured by overheating in (5) a step of laminating and forming by heating press using at least two single-sided circuit boards. Go through And wherein the door.

  In the copper-clad laminate for a multilayer printed wiring board according to the first aspect of the present invention, the strength of the conductive bump made of the conductive paste is increased and the adhesive is bonded even after receiving the thermal history in the heat treatment process. The resin layer can maintain a low melt viscosity. As a result, the shape of the via hole can be maintained with high accuracy, and the adhesive resin can be satisfactorily filled between the circuits.

In the copper-clad laminate for a multilayer printed wiring board according to claim 2 of the present invention, the hard insulating layer is obtained by strengthening the hardness with an inorganic woven fabric, an inorganic nonwoven fabric, an organic woven fabric, or an organic nonwoven fabric. The strength of the copper-clad laminate for multilayer printed wiring boards and multilayer printed wiring boards can be improved.

In the copper-clad laminate for multilayer printed wiring boards according to claim 3 of the present invention, the copper-clad laminate for multilayer printed wiring boards according to any one of claims 1 and 2 is used. Therefore, the shape of the via hole is maintained with high accuracy, and the adhesive resin is satisfactorily filled between the circuits, and the insulating property is excellent.

In the method for producing a multilayer printed wiring board according to claim 4 of the present invention, a multilayer printed wiring board having excellent insulating properties can be obtained.

  First, an embodiment according to a copper-clad laminate for a multilayer printed wiring board will be described. The copper-clad laminate for a multilayer printed wiring board according to this embodiment is obtained by integrating a plurality of single-sided circuit boards each having an adhesive resin layer by heating and pressurizing them using a heating press. This is a raw material for producing the single-sided circuit board used for manufacturing a multilayer printed wiring board having a structure.

  The copper-clad laminate 1 for a multilayer printed wiring board of this embodiment is formed by curing a copper foil 2 and a thermosetting resin as shown in FIG. 1, and softens in a temperature range of 100 ° C. to 400 ° C. The hard insulating layer 3 not to be bonded, the adhesive resin layer 4 that can be temporarily melted in the above temperature range, and the protective film 5 are arranged and integrated in this order.

  The hard insulating layer 3 in the copper-clad laminate 1 for a multilayer printed wiring board according to the present embodiment is formed by curing a thermosetting resin, and is cured and is in a temperature range of 100 ° C. to 400 ° C. It does not soften and does not melt in the layer forming process using a hot press or the like. Examples of the thermosetting resin for forming the hard insulating layer 3 include an epoxy resin, a bismaleimide triazine resin, and a modified PPE resin.

  Moreover, it is preferable that the hard insulating layer 3 is one whose hardness is enhanced by an inorganic base material such as an inorganic woven fabric or an inorganic nonwoven fabric using glass cloth or the like, or an organic base material such as an organic woven fabric or an organic nonwoven fabric.

  As a material for producing the copper-clad laminate 1 for the multilayer printed wiring board of the present embodiment, a normal single-sided copper-clad laminate in which the copper foil 2 and the hard insulating layer 3 are integrated can be used. Woven fabric epoxy resin single-sided copper-clad laminate, glass nonwoven fabric epoxy resin single-sided copper-clad laminate, glass woven fabric bismaleimide triazine resin single-sided copper-clad laminate, aramid nonwoven fabric epoxy resin single-sided copper-clad laminate A glass woven base material modified PPE resin single-sided copper-clad laminate or the like can be used. Moreover, what removed the copper foil of the one side of a double-sided copper clad laminated board can also be used.

  The adhesive resin layer 4 in the copper-clad laminate 1 for multilayer printed wiring boards of the present embodiment can be temporarily melted in the temperature range of 100 ° C. to 400 ° C. by heating.

  In addition, the adhesive resin layer 4 has a minimum melt viscosity (A) measured by a melt viscosity measuring instrument (manufactured by HAKKE) after heat treatment at 100 ° C. for 90 minutes, and a minimum melt viscosity (B) before the heat treatment. The ratio satisfies the following formula (a).

1 ≦ (A / B) ≦ 10 (a)
When the value of (A / B) exceeds 10, the viscosity of the adhesive resin layer 4 becomes too high when the heat treatment is performed in advance before the heat press step, and the adhesive resin is placed between the circuits during the heat press. It may not be possible to fully fill. The value of (A / B) is more preferably 5 or less, and further preferably 3 or less.

  Here, the minimum melt viscosity of the adhesive resin layer 4 is preferably 300 Pas · S or less, and more preferably 250 Pas · S or less.

  As the adhesive resin layer 4 in the present embodiment, a thermosetting resin or a thermoplastic resin can be used, but it is more preferable to use a thermosetting resin in terms of adhesive strength, heat resistance, and chemical resistance.

  Furthermore, the adhesive resin layer 4 preferably contains an epoxy resin and a curing agent, and the curing agent is preferably incompatible with the epoxy resin at a temperature of 100 ° C. or lower.

  By setting it as such a structure, even after receiving the heat history in the heat processing process of an electrically conductive paste, it can suppress that the melt viscosity of the adhesive resin layer 4 rises. In other words, the curing of the epoxy resin can be delayed by making the curing agent incompatible with the matrix in the epoxy resin and making the epoxy resin difficult to initiate a curing reaction until the curing agent itself melts.

  More specifically, the adhesive resin layer 4 is a thermosetting resin mainly composed of an epoxy resin and dicyandiamide used as a curing agent for the epoxy resin dissolved in a solvent such as dimethylformamide. After applying this adhesive layer component on the hard insulating layer, a solvent such as dimethylformamide is gently removed by drying to obtain an incompatible matrix of dicyandiamide as a curing agent in the epoxy resin. Can do. This is because dicyandiamide is difficult to dissolve in the epoxy resin, and the solvent dimethylformamide has a property of being selectively dissolved in the epoxy resin.

  In this way, in a state where the curing agent is scattered in an incompatible state in a matrix, since the two are not compatible with each other with a heat history of 100 ° C. or less, the possibility that the epoxy resin will cause a crosslinking reaction is reduced. As a result, curing of the epoxy resin can be suppressed.

  Therefore, the shape of the tip portion of the conductive paste after hot pressing can be controlled by adopting the above-described configuration of epoxy resin and curing agent and by setting the heat treatment temperature in the heat treatment step of the conductive paste to 100 ° C. or less. In addition, it is possible to suppress the occurrence of a filling problem between circuits due to an increase in the viscosity of the adhesive resin layer 4.

  As a method for forming the adhesive resin layer 4, for example, an adhesive resin containing an epoxy resin and a curing agent is applied to the above-described single-sided copper-clad laminate by means of a roll coater, curtain coater, spray coater, screen printing, or the like. Precuring is performed, or the adhesive sheet is laminated on a single-sided copper-clad laminate using a hot roll or the like. The thickness of the adhesive resin layer 4 is preferably in the range of 10 to 50 μm.

  Note that a curing agent having a high curing temperature may be used, and a blending system that does not accelerate curing at a heating temperature of 100 ° C. or less may be set.

  Although the protective film 5 in the copper-clad laminate 1 for multilayer printed wiring boards of this embodiment is not particularly limited, an aqueous copper chloride solution in which the copper-clad laminate 1 for multilayer printed wiring boards is immersed during circuit formation Those having chemical resistance against sodium hydroxide aqueous solution and the like are preferable, and specific examples thereof include polyethylene terephthalate films. Further, when the protective film 5 is peeled off during the process of forming the circuit on the copper-clad laminate 1 for the multilayer printed wiring board, there is a problem that the adhesive resin layer 4 is exposed to contaminate the solution used in the circuit forming process. Therefore, the protective film 5 is required to have adhesion to the adhesive resin layer 4. Thus, since the protective film 5 functions as a protective layer for the adhesive resin layer 4 in the step of forming a circuit on the copper-clad laminate 1 for multilayer printed wiring boards, the surface of the protective film 5 on the adhesive resin layer 4 side is in close contact. The surface roughness (Rz) is preferably in the range of 0.01 to 5 μm in order to ensure the properties. On the other hand, since the protective film 5 is peeled off from the single-sided circuit board before a plurality of single-sided circuit boards having the obtained adhesive resin layer 4 are overlaid, the protective film 5 is required to have peelability. It is done.

  Moreover, about the film thickness of the protective film 5, it is preferable that it exists in the range of 5-100 micrometers in the following reason. In manufacturing the multilayer printed wiring board, after forming a circuit on the copper foil 2 surface of the copper-clad laminate 1 for the multilayer printed wiring board, the protective film 5 and the adhesive resin layer are punched from the protective film 5 side. 4 and the hard insulating layer 3 are formed to form a bottomed hole that contacts the circuit, and then a conductive substance is printed in the bottomed hole from the protective film 5 side in order to impart conductivity to the bottomed hole. Fill. Next, after removing excess conductive material on the surface with a squeegee or the like and flattening, the protective film 5 is peeled off to form conductive bumps that protrude at substantially the same height as the thickness of the protective film 5. Since the desirable range of the protruding height of the conductive bump is 5 to 100 μm, it is preferable that the film thickness of the protective film 5 be in the range of 5 to 100 μm.

  Next, the manufacturing method of the multilayer printed wiring board of this invention and embodiment about a multilayer printed wiring board are described.

In the embodiment according to the method for producing a multilayer printed wiring board of the present invention, the above-described copper-clad laminate 1 for multilayer printed wiring board is used,
(1) forming a circuit on the copper foil 2 surface of the copper-clad laminate 1 for multilayer printed wiring board;
(2) A step of forming a bottomed hole that touches the circuit through the protective film 5, the adhesive resin layer 4, and the hard insulating layer 3 by perforating from the protective film 5 surface side
(3) A step of printing and filling a conductive paste using a thermosetting resin as a binder resin in the bottomed hole to impart conductivity to the bottomed hole;
(4) The process of producing the single-sided circuit board which hardened the conductive paste front-end | tip preferentially by peeling off the protective film 5 and heat-processing in the state which protruded the said conductive paste front-end | tip part,
(5) A multilayer printed wiring board is manufactured through the process of carrying out a lamination | stacking shaping | molding with a hot press using at least 2 piece of said single-sided circuit boards.

  Hereinafter, it demonstrates based on FIG.2, FIG.3, FIG.4 in order of a process.

  First, a single-sided copper-clad laminate 6 as shown in FIG. 2A is prepared as a material in which the copper foil 2 with no circuit formed and the hard insulating layer 3 are integrated. Next, as shown in FIG. 2B, the adhesive resin layer 4 is formed on the surface of the single-sided copper-clad laminate 6 opposite to the copper foil 2. The adhesive resin layer 4 is precured by applying an adhesive containing a thermosetting resin such as an epoxy resin and a curing agent by means of a roll coater, a curtain coater, a spray coater, screen printing, or the like, or an epoxy resin or the like It can form by laminating | stacking the adhesive sheet containing this thermosetting resin and a hardening | curing agent using a hot roll etc. Next, the protective film 5 is laminated on the surface of the adhesive resin layer 4 using a heat roll to produce a copper-clad laminate 1 for a multilayer printed wiring board as shown in FIG.

  Next, a photosensitive dry film is laminated on the copper foil 2 of the copper-clad laminate 1 for multilayer printed wiring boards, and each process of exposure, development, etching, and peeling is performed to form the copper foil 2 in a predetermined pattern. The circuit 7 is formed as shown in FIG.

  Next, as shown in FIG. 2 (e), from the protective film 5 side, a bottomed hole 8 that perforates and penetrates the protective film 5, the adhesive resin layer 4 and the hard insulating layer 3 and contacts the circuit 7 is formed. Form. The circuit 7 forms the bottom of the bottomed hole 8. The perforating process is preferably performed by a carbon dioxide laser from the protective film 5 side. When it is necessary to remove the laser smear (residue) generated at that time, a desmear method using permanganic acid may be used, or the residue may be removed with a UV laser.

  Next, conductivity is imparted to the bottomed hole 8. The conductivity can be imparted by imprinting a conductive paste 9 into the bottomed hole 8 by screen printing as shown in FIG. Next, by peeling off the protective film 5, the conductive bumps 10 formed by protruding the conductive paste 9 are protruded from the surface of the adhesive resin layer 4 as shown in FIG. The protruding height of the conductive bump 10 is preferably 5 to 100 μm in order to improve the connectivity with other circuit boards in the subsequent steps. Thus, the single-sided circuit board 11a having the adhesive resin layer 4 is produced. Similarly, single-sided circuit boards 11b, 11c, and 11d as shown in FIG. 3 are manufactured.

  Next, the conductive paste front end portion is preferentially cured by heat treatment with the conductive paste front end portion protruding. The heat treatment here is preferably performed at a temperature of 100 ° C. or lower, preferably 50 to 100 ° C. for several tens of minutes.

  Next, as shown in FIG. 3, the single-sided circuit boards 11a, 11b, 11c, and 11d are overlapped and temporarily fixed by a welding method or a pin laminating method using guide holes and guide pins. In this way, the single-sided circuit boards superimposed on each other are integrated by lamination using heating and pressurization using a heating press to produce the multilayer printed wiring board 12 shown in FIG. A vacuum heating press is preferably used as the heating press. By heating and pressurizing using a heating press, the adhesive resin layer 4 is once melted and then cured, and the conductive paste 9 is also in close contact with the corresponding circuit and thermally cured to form a via hole. The multilayer printed wiring board 12 having the IVH structure shown in FIG. 4 can be obtained.

  Below, the Example of this invention is described in detail based on FIG.

  As a single-sided copper-clad laminate 6 shown in FIG. 2 (a), an FR-4 grade glass woven fabric base epoxy resin single-sided copper-clad laminate (manufactured by Matsushita Electric Works, product number R-1761, thickness 0.1 mm) , Copper foil thickness 18 μm) was used.

  Next, bisphenol A brominated epoxy resin methyl ethyl ketone solution (Dow Chemical Co., DER514): 80 wt%, O cresol novolac type epoxy resin methyl ethyl ketone solution (Dainippon Ink Co., Ltd., EPICLON-N-690) : 7 wt%, ethane-type solid epoxy resin (Japan Epoxy Resin Co., Ltd., EOPN1031): 5 wt%, dicyandiamide (Nihon Carbide Co., Ltd.) dimethylformamide 10% solution: 8 wt% 2 is applied using a roll coater so as to have a thickness of 30 μm, and heated (50 ° C., 60 minutes) until tackiness disappears to form an adhesive resin layer 4 as shown in FIG. Formed.

  Next, using a laminator (temperature 50 ° C., pressure 0.05 MPa), a polyethylene terephthalate film (manufactured by Toray Industries, Inc., product number T-60, thickness 38 μm) as a protective film 5 is rolled onto the surface of the adhesive resin layer 4. Lamination was performed to produce a copper-clad laminate 1 for multilayer printed wiring boards as shown in FIG.

  Next, a photosensitive dry film was laminated on the copper foil 2 of the copper-clad laminate 1 for multilayer printed wiring boards, exposed and developed. Further, etching was performed using a cupric chloride solution, and then the dry film was peeled off using a sodium hydroxide solution to form a circuit 7 as shown in FIG.

  Next, as shown in FIG. 2 (e), from the protective film 5 side, a bottomed hole 8 that perforates and penetrates the protective film 5, the adhesive resin layer 4 and the hard insulating layer 3 and contacts the circuit 7 is formed. Formed. In the perforating process, after a hole was formed using a carbon dioxide laser from the protective film 5 side, the residue was removed using a UV laser so that no residue remained on the surface of the circuit 7 in the bottomed hole 8.

  Next, in order to impart conductivity to the bottomed hole 8, as shown in FIG. 2 (f), the bottomed hole 8 was filled with a conductive paste 9 mainly composed of silver by screen printing. . Next, by peeling off the protective film 5, as shown in FIG. 2G, the conductive bumps 10 formed by protruding the conductive paste 9 are protruded from the surface of the adhesive resin layer 4. A single-sided circuit board 11a having the layer 4 was produced.

  Thereafter, the single-sided circuit board 11a was heat-treated at 100 ° C. for 90 minutes. Here, the melt viscosity of the adhesive resin layer 4 before and after the heat treatment was measured under the condition of a temperature increase rate of 4 ° C./min using a melt viscosity measuring device (manufactured by HAKKE). As a result, the ratio (A / B) between the lowest melt viscosity (A) after the heat treatment and the lowest melt viscosity (B) before the heat treatment was 2.

  Similarly, single-sided circuit boards 11b, 11c, and 11d shown in FIG. 3 were produced. Next, the single-sided circuit boards 11a, 11b, 11c, and 11d were overlapped and temporarily fixed by a pin laminating method for alignment.

  In this way, each of the single-sided circuit boards 11a, 11b, 11c, and 11d is superposed and heated under a vacuum using a heating press (180 ° C., 1 hour) to obtain FIG. The multilayer printed wiring board 12 shown was obtained. The obtained multilayer printed wiring board 12 was obtained by accurately forming the conductive bumps 10 as via holes.

  As described above, the copper-clad laminate 1 for a multilayer printed wiring board according to the present embodiment increases the strength of the conductive bumps 10 made of the conductive paste 9, and after receiving a thermal history in the heat treatment process. The adhesive resin layer 4 can maintain a low melt viscosity. As a result, the shape of the via hole can be maintained with high accuracy and the adhesive resin can be satisfactorily filled between the circuits.

  Moreover, since the epoxy resin and the hardening | curing agent are contained as the adhesive resin layer 4, the several copper clad laminated board 1 for multilayer printed wiring boards can be adhere | attached favorably.

  Further, since the curing agent is incompatible with the epoxy resin at a temperature of 100 ° C. or lower, in order to increase the strength of the conductive bump 10 composed of the conductive paste 9, it is preheated before the heating press step. Even if the treatment is performed, the curing reaction of the adhesive resin layer 4 can be suppressed, and as a result, the adhesive resin layer 4 can maintain a low melt viscosity.

  In addition, since the hard insulating layer 3 is strengthened with a glass woven fabric base material, the strength of the resulting multilayered printed wiring board copper-clad laminate 1 and multilayer printed wiring board 12 can be improved.

  In addition, the multilayer printed wiring board 12 according to the present embodiment maintains the shape of the via hole with high accuracy, is well filled with resin between circuits, and has excellent insulating properties.

  Moreover, in the manufacturing method of the multilayer printed wiring board 12 in this embodiment, the multilayer printed wiring board excellent in insulation can be obtained.

It is sectional drawing of the copper clad laminated board 1 for multilayer printed wiring boards in embodiment of this invention. It is sectional drawing which shows each process for demonstrating embodiment which concerns on the manufacturing method of the multilayer printed wiring board 12 of this invention. It is sectional drawing which shows the process following FIG. 2 for describing embodiment which concerns on the manufacturing method of the multilayer printed wiring board 12 of this invention. It is sectional drawing for demonstrating embodiment which concerns on the multilayer printed wiring board 12 of this invention. It is sectional drawing which shows each process for demonstrating a prior art. It is sectional drawing which shows the process following FIG. 5 for demonstrating a prior art. It is sectional drawing for demonstrating the multilayer printed wiring board of a prior art. It is sectional drawing for demonstrating the multilayer printed wiring board of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copper clad laminated board for multilayer printed wiring boards 2 Copper foil 3 Hard insulating layer 4 Adhesive resin layer 5 Protective film 9 Conductive paste 10 Conductive bump 12 Multilayer printed wiring board

Claims (4)

Copper foil,
A hard insulating layer formed by curing a thermosetting resin and not softening in a temperature range of 100 ° C. to 400 ° C .;
An adhesive resin layer that can be temporarily melted in the temperature range;
Protective film,
It is a copper-clad laminate for multilayer printed wiring boards that is arranged and integrated in this order,
The adhesive resin layer is prepared by mixing dicyandiamide used as a curing agent for epoxy resin in dimethylformamide in a thermosetting resin mainly composed of epoxy resin, and is increased by a melt viscosity meter. The ratio of the minimum melt viscosity (A) after the heat treatment at 100 ° C. for 90 minutes and the minimum melt viscosity (B) before the heat treatment measured at a temperature rate of 4 ° C./min is expressed by the following formula (a ),
1 ≦ (A / B) ≦ 10 (a)
A copper-clad laminate for multilayer printed wiring boards characterized by satisfying 2. The copper-clad laminate for a multilayer printed wiring board according to claim 1, wherein the hard insulating layer according to claim 1 is reinforced by an inorganic woven fabric, an inorganic nonwoven fabric, an organic woven fabric, or an organic nonwoven fabric . A multilayer printed wiring board produced by using a plurality of copper-clad laminates for multilayer printed wiring boards according to any one of claims 1 and 2. A method for producing a multilayer printed wiring board, comprising the following steps.
(1) A step of forming a circuit on the copper foil surface of the copper-clad laminate for a multilayer printed wiring board according to any one of claims 1 and 2;
(2) A step of forming a bottomed hole that touches the circuit through the protective film, the adhesive resin layer, and the hard insulating layer by perforating from the protective film surface side;
(3) A step of printing and filling a conductive paste using a thermosetting resin as a binder resin in the bottomed hole to impart conductivity to the bottomed hole;
(4) A step of producing a single-sided circuit board in which the conductive paste tip is hardened preferentially by performing a heat treatment in a state where the protective film is peeled off and the conductive paste tip is protruded;
(5) A step of laminating and forming with at least two single-sided circuit boards using a hot press .

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