JP2005251895A - Multilayer wiring board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer wiring board in which a surface unevenness is small and which is suitable for fine wiring nature. <P>SOLUTION: The multilayer wiring board includes an insulating resin with a support having an insulating resin layer covered on a support and manufactured by laminating the insulating resin so as to be opposed to the wiring formed on the board or the wiring board. As the insulating resin layer, a thermosetting insulating resin composition which has a melting viscosity at 40°C of 8,000-50,000 Pas and a lowest melting viscosity of 10-400 Pas is used. The laminating step is performed at a temperature lower by 10°C than the temperature showing the lowest melting viscosity of the insulating resin layer. A method of manufacturing the same is provided. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a multilayer wiring board and a method for manufacturing a multilayer wiring board.

  A multilayer wiring board is generally manufactured by the following method. On the insulating substrate on which the wiring is formed, a material called a prepreg, which is made by impregnating a base material such as a glass cloth with an insulating resin such as an epoxy resin and semi-cured, and the copper foil are laminated and integrated by hot pressing. . Then, a hole called a through hole for interlayer connection is made with a drill. Electroless plating of a conductor such as copper is performed on the inner wall of the through hole and the surface of the copper foil, and if necessary, electrolytic plating is further performed so that the plating film has a necessary thickness as a wiring conductor. Thereafter, unnecessary conductors are removed.

  By the way, in recent years, as electronic devices are further reduced in size, weight, and multifunction, LSIs and chip parts are highly integrated. In addition, the form of high integration is rapidly changing to multi-pin or miniaturization. Based on such a flow, in order to improve the mounting density of electronic components also in multilayer wiring boards, development of fine wiring has been advanced. As a manufacturing method of multilayer wiring board that meets this requirement, a build-up multilayer wiring board that does not include a substrate, uses only insulating resin instead of prepreg, and forms wiring layers while connecting only necessary parts with via holes. There is. This build-up method is now becoming mainstream as a method suitable for weight reduction, miniaturization, and miniaturization.

  As a method of forming an insulating layer by a build-up method, a laminate method in which layers are laminated and heat-pressed, a press method in which pressure or vacuum is applied, or a curtain coat method in which a liquid resin is directly applied onto a substrate on which wiring is previously formed. The roll coat method and the like are implemented. Among them, the laminate method is promising because it can improve productivity because an insulating layer can be formed simultaneously on both sides in a short time.

  However, when the insulating layer is formed by the laminate method, it is important to increase the accuracy of the subsequent wiring formation that the insulating resin can follow between the wirings and through holes, especially via holes, and that the formed insulating layer is smooth. It is. In particular, since the aspect ratio of the via hole portion is increased as the diameter of the via hole is reduced, it is difficult to fill the interior with the insulating resin. However, if there is an unfilled portion inside the via hole, flow to the unfilled portion occurs due to a decrease in viscosity of the insulating resin when the insulating resin is heated and cured. This portion causes a recess in the upper portion of the via hole after the insulating layer is cured. Needless to say, the size of the recess may be about 10 μm, which hinders the accuracy of later wiring formation.

  Up to now, for example, an adhesive film excellent in wiring filling property (see Patent Document 1) due to the softening point of the resin used being lower than the lamination temperature, handleability in a semi-cured state, and insulating resin by cross-linked NBR particles Coating film modification (see Patent Document 2) is disclosed.

  From these prior arts, a certain effect can be expected in terms of measures from the composition side of the adhesive film excellent in wiring filling property and the modification of the coating film.

However, in order to achieve both the filling property of the insulating resin and the prevention of dents, the insulating resin changes in fluidity due to storage, a difference occurs depending on the dry state and the resin system, and the curable insulating resin. Although it is necessary to quantitatively grasp that the viscosity once decreases due to heating and then increases, these points are not suggested in the above patent document.
As a result of conducting research to solve filling properties and prevention of dents, we have found that it is important to control the melt viscosity value of the insulating resin layer. In addition, the inventors have found a two-stage curing method capable of adjusting the fluidity in the curing method of the insulating resin layer.
Japanese Patent Laid-Open No. 11-87927 JP 2000-256537 A

  The present invention is a method capable of forming a flat insulating layer while manufacturing a wiring board or a multilayer wiring board by a laminate method, and in particular, the indentation of the insulating layer can be reduced to 2 μm or less, which is suitable for miniaturization. It aims to provide a method.

The present invention is a multilayer wiring board produced by laminating an insulating resin with a support, with an insulating resin layer deposited on the support, so as to face the wiring formed on the substrate or the wiring board. ,
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
The present invention relates to a multilayer wiring board characterized in that the laminating step is performed at a temperature lower by 10 ° C. or more than a temperature showing a minimum melt viscosity of an insulating resin layer.

The present invention is a method of manufacturing a multilayer wiring board,
(A) attaching an insulating resin on an insulating support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the surface having the first wiring of the substrate covers the insulating resin layer, and removing the insulating support;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring on the insulating layer to produce a multilayer wiring board;
Including
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
The present invention relates to a method for producing a multilayer wiring board, wherein the laminating step (c) is performed at a temperature lower by 10 ° C. or more than a temperature showing a minimum melt viscosity of an insulating resin layer.

The present invention is a method of manufacturing a multilayer wiring board,
(A) attaching an insulating resin on a support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the insulating resin layer covers the surface of the substrate having the first wiring;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring to produce a multilayer wiring board;
Including
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
In the insulating resin-preparing step (a) with a support, a conductor is used as a support,
The laminating step (c) is performed at a temperature lower by 10 ° C. or more than the temperature indicating the minimum melt viscosity of the insulating resin layer,
The present invention relates to a method for manufacturing a multilayer wiring board, wherein the second wiring is formed by processing the support in the second wiring formation and multilayer wiring board manufacturing step (e).

  The present invention provides a multilayer wiring board and a method for manufacturing the multilayer wiring board.

  In the present invention, in the case of using an insulator as a support or a conductor as a support for manufacturing a multilayer wiring board, the handling of the support is different as in the method described later. Is going.

According to one method of the present invention, to manufacture a multilayer wiring board,
(A) attaching an insulating resin on an insulating support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the surface having the first wiring of the substrate covers the insulating resin layer, and removing the insulating support;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring on the insulating layer to produce a multilayer wiring board;
I do.
According to the present invention, as the insulating resin layer, a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s is used.
The laminating step (c) is performed at a temperature lower by 10 ° C. or more than the temperature indicating the minimum melt viscosity of the insulating resin layer.

According to one method of the present invention, to manufacture a multilayer wiring board,
(A) attaching an insulating resin on a support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the insulating resin layer covers the surface of the substrate having the first wiring;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring to produce a multilayer wiring board;
I do.
According to the present invention, as the insulating resin layer, a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s is used.
In the insulating resin-preparing step (a) with a support, a conductor is used as the support,
The laminating step (c) is performed at a temperature lower by 10 ° C. or more than the temperature indicating the minimum melt viscosity of the insulating resin layer,
In the second wiring formation and multilayer wiring board manufacturing step (e), the second wiring is formed by processing the support.

According to the method of the present invention, in the curing step (d), the main curing step is performed after the preliminary curing step, and the preliminary curing step is performed at a temperature lower by 40 to 80 ° C. than the main curing temperature for 10 to 90 minutes. It is preferable. Subsequent to the curing step (d), it is preferable to perform (f) a step of forming a through or non-through electrical connection hole in the insulating layer.
In the laminating step (c), it is preferable to perform the smoothing treatment step simultaneously by heating and pressurizing with a rigid plate so as to face the support surface of the insulating resin with support. Alternatively, after the laminating step (c) and before the curing of the insulating resin layer and the step of forming the resin layer (d), a plate having high rigidity so as to face the support surface of the insulating resin with support. It is preferable to perform the smoothing treatment by heating and pressurizing.
In the step (a) for producing the insulating resin with a support, an insulating resin composition is applied to a thickness of 20 to 100 μm on a support with a thickness of 10 to 100 μm and dried to produce an insulating resin with a support. It is preferable that it is a process.
And it is preferable that an insulating resin composition is a resin composition from which a viscosity once falls by heating and a viscosity rises after that. As this insulating resin composition, it is preferable to use a resin composition containing an epoxy resin and cyanoethylated imidazole.

  In the present invention, the multilayer wiring board is a wiring board in which conductor patterns (wirings) are formed in three or more layers including the surface conductor layer. Similarly, a single-sided wiring board is a wiring board with wiring on only one side, and a double-sided wiring board is a wiring board with wiring on both sides. These wirings are wirings for connecting parts based on circuit design, but some or all of them can be parts or circuits. Further, the multilayer wiring board can have through-holes or non-through holes in each layer.

  Hereinafter, an example of a method for manufacturing a multilayer wiring board of the present invention will be described in detail with reference to the drawings schematically showing an example of an embodiment of the present invention. In FIG. 1, an example of the manufacturing method of the multilayer wiring board of this invention is shown.

  According to the present invention, the insulating resin layer 12 is deposited on the support 11 to produce the insulating resin 1 with a support (not shown). Also, a conductor layer 22 is formed on one surface of the substrate 21 (not shown), and unnecessary conductor portions are removed so as to form a desired conductor pattern, thereby forming a first wiring (or inner layer circuit) 22a. Then, the single-sided wiring board 2 is produced (not shown). The insulating resin 1 with the support is placed on the single-sided wiring board 2 so that the surface of the insulating layer 1 of the manufactured insulating resin 1 with the support faces the surface having the first wiring 22a of the single-sided wiring board 2 that is manufactured. Overlapping (see FIG. 1 (a)).

  The insulating resin 1 with support and the single-sided wiring board 2 thus laminated are laminated by heating and pressure-bonding so that the first wiring 22a of the single-sided wiring board 2 is covered with the insulating resin layer 12. Lamination is performed by first laminating the laminates, and then a laminate plate 3 made of stainless steel (for thermocompression bonding) is attached to the laminator, and the laminate plate 3 is pressed against the support 11 side for lamination. It is preferable. Optionally, the lamination can be repeated several times. After the lamination, the support 11 is removed, and then the insulating resin layer 12 is heated and cured to form the insulating layer 12 (see FIG. 1B). Here, a single-sided wiring board in which wiring is formed only on one side of the substrate is shown, but a double-sided wiring board can also be used as follows.

  In FIGS. 1A and 1B, the example in which the insulating layer 12 is laminated on one side of the wiring board 2 has been described. However, in particular, when the wiring board has the wirings 22a and 22a ′ on both sides, the wiring Insulating layers can be laminated on both sides of the plate. In that case, two insulating resins 1 and 1 'with a support are used, and the insulating resin 1 with a support, the wiring board 2, and the insulating resin 1' with a support are arranged in this order in the wiring 22a, 22a 'of the wiring board. Are arranged so that the surfaces of the insulating layers 1 and 12 'of the support-attached insulating resins 1 and 1' face each other, and the whole is subjected to thermocompression bonding. In other words, it is preferable that the insulating resin with a support is overlapped on both surfaces of the wiring board so that the support side is on the outside, and thermocompression-bonded so as to be sandwiched between the respective support surfaces and the laminate plate 3. After lamination, the support plate 11 can be removed and the resin can be heat-cured in the same manner as the single-sided wiring board.

  Following the procedure shown with reference to FIGS. 1A and 1B, one or more through or non-through holes 5 a are formed in the insulating layer 12 by laser cutting, wet etching, drill cutting, or the like. Form (Figure (c)). In order to improve adhesion to the conductor layer 22, it is preferable to chemically or mechanically roughen the surface of the insulating layer (not shown).

  A conductor layer 22 is formed on the surfaces of the through-holes and / or non-through-holes 5a formed in the insulating layer 12 and the insulating layer 12 by electroless plating or the like (not shown). In order to remove an unnecessary conductor portion and form a conductor pattern, an etching resist pattern corresponding to a desired conductor pattern is formed on the conductor layer 22 and then etched to remove the unnecessary conductor portion. Thereafter, the etching resist is removed to form a second wiring (or inner layer circuit or outer layer circuit) 22b, and interlayer connection between the first wiring 22a and the second wiring 22b is performed (FIG. 1D). .

  In the procedure shown with reference to FIG. 1 (b) above, when the support 11 is a conductor, unlike the above description, the conductor layer that forms the second wiring without removing the support 11 22 can be used.

  When the support is a conductor, the insulating resin 1 with the support is so that the surface of the insulating layer 1 of the manufactured insulating resin 1 with the support faces the surface having the second wiring 22b of the manufactured multilayer wiring board. Is stacked on a multilayer wiring board (not shown). The laminated insulating resin 1 with support and the multilayer wiring board are laminated by heating and pressure-bonding so that the insulating resin layer 12 covers the second wiring 22b (FIG. 1E). Thereafter, a through or / and non-through hole 5b is formed in the same manner as described above (FIG. 1 (f)). Next, in the same manner as described above, a third wiring (or inner layer circuit or outer layer circuit) 22c is formed, and interlayer connection between the second wiring 22b and the third wiring 22c is performed (FIG. 1G).

  Below, the modification in the manufacturing method of the multilayer wiring board of this invention and the material to be used are demonstrated.

  According to the present invention, in the step of (a) depositing an insulating resin layer on a support to produce an insulating resin with a support, when the support is an insulator, the support is a conductor. In both cases, known methods can be used. For example, as a method of forming an insulating resin layer on a support, a method of uniformly applying an insulating resin composition to a support and drying it to form a layer, a method of laminating a layer of insulating resin previously formed into a layer, etc. Can be used.

  In the step (a) of the present invention, the resin composition is applied to the surface of the support by, for example, a known method such as a roll coater, comma coater, gravure coater, air knife coater, die coater, or bar coater and dried. It can form preferably. At that time, the resin composition may be used after diluting in an arbitrary solvent as necessary. Examples of the diluting solvent include methyl ethyl ketone, xylene, toluene, acetone, ethylene glycol monoethyl ether, cyclohexanone, ethyl ethoxy Pionate, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be preferably used. These solvents may be used alone or in a mixed system. The blending ratio of the solvent to the resin composition may be appropriately adjusted according to the composition of the resin composition and the method of forming a coating film. For example, when coating on a support with a comma coater, generally the solvent is excluded. It is preferable to adjust the amount of the solvent used so that the solid content is about 30% to about 60%.

  Drying after coating can be performed at 80 to 110 ° C. for about 1 to 10 minutes. When the drying temperature is lower than 80 ° C. and the time is less than 1 minute, the drying does not proceed sufficiently and the amount of residual solvent in the insulating resin layer increases, and as a result, the residual solvent volatilizes into the insulating resin layer. There is a risk of voids. On the other hand, when the drying temperature is higher than 110 ° C. and the time exceeds 10 minutes, the drying proceeds too much and the melt viscosity at 40 ° C. and the minimum melt viscosity are increased due to the progress of the reaction on the surface of the insulating resin layer. May occur.

  The thickness of the insulating resin layer (thickness after drying) is preferably not less than the minimum film thickness that can ensure the minimum insulation distance from the viewpoint of insulation. Although this minimum insulation distance varies depending on the composition of the insulating resin composition, it is generally preferably 30 to 40 μm or more. Increasing the thickness of the insulating resin layer is advantageous in terms of insulation, but on the other hand, it is usually preferable to set the thickness to about 60 μm or less from the viewpoint of economy.

  The support (support 11 in FIG. 1 described above) used in the step (a) of the present invention is not particularly limited. For example, when the support is an insulator (insulating support), various thermoplastic plastic films such as polyethylene terephthalate, polypropylene, polyethylene, and polyester can be preferably used. Alternatively, when the support is a conductor (conductive support), a metal foil such as an aluminum foil or a copper foil can be used. The thickness is not particularly limited, but is preferably 10 μm or more from the viewpoints of handling properties, coating properties of the insulating layer (wrinkle generation), and the like, and is 100 μm or less from the viewpoint of reducing material costs. Preferably, it is 15 to 70 μm. In the case where the support is used as a part of the wiring board, it is preferable to use a conductive support, and in order to improve the adhesion between the conductive support and the insulating resin layer, surface treatment is performed in advance (for example, roughening treatment). Or surface treatment described later) is preferable.

  The insulating resin layer (insulating resin layer 12 in FIG. 1 described above) in the step (a) of the present invention has a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s. A resin composition is used. The melt viscosity at 40 ° C. of the insulating resin composition is important to be 8000 to 50000 Pa · s, preferably 8000 to 30000 Pa · s, in consideration of handleability due to the balance between the powdery edge at the time of cutting and tackiness. s. In addition, the minimum melt viscosity of the insulating resin composition is such that the insulating resin layer can sufficiently follow the uneven shape of the inner layer circuit during lamination, and there is no unfilled portion inside the substrate, and it does not flow too much during lamination. Considering that the resin layer does not ooze out, it is important that it is 10 to 400 Pa · s, preferably 10 to 200 Pa · s. The insulating resin with a support according to the present invention can be sufficiently laminated by laminating, for example, in a pattern in which the distance between the inner layer circuits is 1000/1000 mm at the maximum or a pattern in which many round holes with a diameter of 5 mm exist. And the dent on the surface of the insulating resin layer can be set to 2 μm or less, for example.

The melt viscosity at a specific temperature of the insulating resin composition is determined from a melt viscosity curve that the insulating resin with a support exhibits under predetermined heating and vibration conditions. Examples of this measuring method include the following methods.
(1) Only the insulating resin composition is taken out from the insulating resin with a support and powdered.
(2) A predetermined amount of the powder obtained in the above (1) is weighed, and a tablet sample having a diameter of 20 mm is prepared by a tablet molding machine.
(3) The sample (2) is heated and shaken from room temperature to 200 ° C. using a viscosity / viscoelasticity measuring device to obtain a melt viscosity curve.

  According to the present invention, the components constituting the insulating resin composition are not particularly limited as long as they have the above-described resin melt viscosity characteristics. For the insulating resin composition, for example, an acrylic resin, a styrene resin, an epoxy resin, an amide resin, an amide epoxy resin, an alkyd resin, a phenol resin, etc. can be used alone or in combination. Can be used. In consideration of electrical insulation and solder heat resistance, it is particularly preferable to use an epoxy resin for the insulating resin composition. Furthermore, as a component constituting the insulating resin composition, a curing agent for the resin, an additional high molecular weight compound different from the main component resin, and the like can be included depending on circumstances.

  Examples of the epoxy resin include bisphenol A type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, alicyclic epoxy resin, aliphatic chain Epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, diglycidyl etherified product of bisphenol, diglycidyl etherified product of naphthalenediol, diglycidyl etherified product of phenol, diglycidyl of alcohol Etherified products, alkyl-substituted products thereof, halides, hydrogenated products, and the like can be used. These epoxy resins can be used alone or in combination of two or more. Among these, it is preferable to use a liquid epoxy resin and a solid epoxy resin in combination in consideration of the resin melt viscosity characteristics. For example, it is preferable to use a bisphenol A type epoxy resin and a cresol novolac type epoxy resin in combination.

  The curing agent in the case of using an epoxy resin is not particularly limited. As a hardening | curing agent, what is generally used as an epoxy resin hardening | curing agent, such as an amine hardening | curing agent and an acid anhydride hardening | curing agent, can be used. From the viewpoint of storage stability, cyanoethylated imidazole is preferred as the curing agent.

  Examples of cyanoethylated imidazole, ie, cyanoethylated imidazole, include 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl. 2-Phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate and 1-cyanoethyl-2-phenylimidazolium trimellitate can be preferably used. These can be used alone or in combination of two or more. These cyanoethylated imidazoles are preferably used in an amount of 0.1 to 1.0 parts by weight with respect to 100 parts by weight of the epoxy resin from the viewpoint of curability and the like.

  That is, for the insulating resin composition as the insulating resin used in the step (a) of the present invention, a resin composition containing an epoxy resin and a cyanoethylated imidazole as main components can be preferably used. Further, it is also preferable to use other resins and / or other curing agents in combination as an additional high molecular weight compound different from the main component resin.

  As the additional high molecular weight compound, for example, rubber compounds such as acrylic rubber, butadiene rubber, and acrylonitrile butadiene rubber, phenoxy resin, polyvinyl butyral resin, and the like can be used. Moreover, these resins and thermosetting agents can be used in combination. For example, a phenol resin and dicyandiamide can be used together, or a phenol resin and cyanoethylated imidazole can be used together. The phenol resin may be of any type such as a novolak type, a cresol novolak type, and a bisphenol novolak type.

  The above-mentioned insulating resin composition is within a range that does not affect the melt viscosity characteristics, for example, a curing accelerator, a plasticizer, an adhesion imparting agent, a leveling agent, a peeling accelerator, an antifoaming agent, an antioxidant, and an ion trap. An additive component such as an agent and a flame retardant may be included.

  According to the present invention, (b) a known method can be used in the step of forming the first wiring on one side or both sides of the substrate to produce the single sided or double sided wiring board. For example, a method in which a metal foil is laminated on a substrate to form a conductor layer, and unnecessary portions are removed by etching or the like to form a first wiring, a method in which metal plating is performed on the substrate to form a conductor layer, Alternatively, a method in which a portion where the first wiring is not formed is previously masked with a resist or the like and then the first wiring is formed by metal plating or the like can be used.

  As a board | substrate (the board | substrate 21 in the above-mentioned FIG. 1) used for the process (b) of this invention, the well-known laminated board used in a well-known wiring board, for example, glass cloth-epoxy resin, paper-phenol resin, paper -Epoxy resin, glass cloth / glass paper-Epoxy resin can be used, and is not particularly limited. The substrate can have through or non-through electrical connection holes, and the size and number of connection holes are not limited. Further, the substrate can further have a planar wiring or a planar circuit in addition to the connection hole.

  The first wiring formed in the step (b) of the present invention is not particularly limited as long as it is a conductor pattern or the like (as described above). The material of the first wiring is, for example, copper, silver, palladium, tungsten, molybdenum, aluminum, polysilicon, or the like. Copper is preferred.

  In the step (b) of the present invention, a surface treatment may be performed as necessary to improve the adhesion of the first wiring surface. This treatment method is also not particularly limited. For example, a copper oxide needle crystal is formed on the surface of the first wiring with an alkaline aqueous solution of sodium hypochlorite, and the formed copper oxide needle crystal is formed. A known method such as reduction by immersion in a dimethylamine borane aqueous solution can be employed.

  When the wiring is formed by a plating method, it is preferable to surface-treat the insulating resin layer with an oxidizing roughening solution or the like in order to improve adhesion. As the oxidizing roughening liquid, a chromium / sulfuric acid roughening liquid, an alkaline permanganic acid roughening liquid, a sodium fluoride / chromium / sulfuric acid roughening liquid, a borofluoric acid roughening liquid, or the like can be used. After the surface treatment, for example, it is immersed in a hydrochloric acid aqueous solution of stannous chloride to carry out a neutralization treatment, and if necessary, a plating catalyst application treatment is carried out in order to deposit and adhere palladium or the like on the entire surface. The plating catalyst application treatment is performed, for example, by immersing in a palladium chloride plating catalyst solution.

  Subsequently, by immersing in an electroless plating solution, an electroless plating layer having a thickness of, for example, about 0.3 to 1.5 μm is deposited on the entire surface of the insulating resin layer. If necessary, electroplating may be further performed so that the wiring conductor has a required thickness. As the electroless plating solution used for electroless plating, a known one can be used, and electroplating can be performed by a known method, neither of which is particularly limited. Thereafter, unnecessary portions are removed by etching, whereby the first wiring is formed.

This etching method is not particularly limited, and any known method can be used.

  In addition to the above method, a plating resist is formed using an insulating resin layer containing a plating catalyst, and the first wiring is formed only at a necessary location by electroless plating, and an insulating resin layer containing no plating catalyst is formed. After roughening and providing a plating catalyst, a method may be employed in which a plating resist is formed and the first wiring is formed only at a necessary portion by an electroless plating method. Alternatively, a pattern plating method may be used. For example, this can be performed using an ultrathin copper foil having a thickness of 3 μm. The insulating resin layer containing the above plating catalyst is, for example, a plating catalyst in which palladium chloride is adsorbed on a highly adsorbing inorganic material such as kaolin or alumina and palladium ions are reduced to a metal with a reducing agent such as dimethylaminoborane (for example, , Cat # 14: manufactured by Hitachi Chemical Co., Ltd.) is added to the insulating resin so that the palladium concentration is 1000 to 3000 ppm.

  According to the present invention, (c) in the step of laminating the insulating resin with a support on the substrate so that the surface having the first wiring of the substrate covers the insulating resin layer, the insulating resin layer A known method procedure can be used except that the temperature is at least 10 ° C. lower than the temperature showing the minimum melt viscosity. This temperature condition is for suppressing generation of voids due to the residual solvent during thermocompression bonding. The thermocompression bonding time is preferably more than 10 seconds and less than 90 seconds, more preferably 20 to 60 seconds, considering the balance between the flow of resin to the wiring (inner layer circuit) and productivity. Regarding the pressurization, if the pressure is too low, the resin does not easily flow to the wiring (inner layer circuit). Therefore, the pressure is preferably 0.2 MPa · s or more. The preferred pressure value also varies depending on the thickness of the substrate, the residual copper ratio, etc., as with the heating temperature. However, if the pressure is too high, the substrate may be deformed, and therefore it is preferably 1.0 MPa · s or less. If the degree of vacuum is 15 hPa · s or more, the embedding property to the wiring board (inner layer circuit board) may be lowered. On the other hand, the lower the degree of vacuum, the better. In view of the influence of the waiting time until the production time on the productivity, etc., it is preferable to carry out in the range of 5 to 10 hPa · s.

  A smoothing treatment can be performed together with the laminating process or after the laminating process. The smoothing process is a process of smoothing the insulating layer by heating and pressurizing with a rigid plate such as a stainless plate so as to face the support surface of the insulating resin with the support.

  As the smoothing treatment, the smoothing treatment is performed simultaneously (together with) the laminating step by heating and pressurizing with a rigid plate so as to face the support surface of the insulating resin with the support during the laminating step. Alternatively, after the laminating step and before the resin curing step, heating and pressurizing with a flat plate having high rigidity so as to face the support surface of the insulating resin with the support can be performed as a separate step from the laminating step. In addition, when the insulating resin with a support is laminated on the surface of the single-sided wiring board on which the first wiring is produced (when laminated on only one side), or the first of the double-sided wiring board In both cases where the wiring is laminated on the surface on which the wiring is formed (when laminated on both surfaces), a highly rigid flat plate can be used as the heating / pressurizing plate on both sides.

  As long as rigidity is high, a material and thickness will not be restrict | limited as a highly rigid flat plate. A thing with high heat conductivity like a metal plate is preferable. Since a flat plate that can be used many times is appropriate, a stainless steel plate or an aluminum plate is particularly preferable. Although the thickness of the flat plate having high rigidity can be increased, it is preferably about 0.5 to 1.0 mm in consideration of uniformity of heat transfer and deformation of the flat plate itself. The dimension of the flat plate having high rigidity preferably has an area that can cover the entire surface of the film with insulating resin.

  The configuration of such a process can be determined by giving priority to manufacturing efficiency and wiring formation accuracy such as circuit filling and smoothness.

  When manufacturing efficiency is taken into consideration, it is preferable to perform laminating and smoothing simultaneously in the laminating step.

  When considering the point that both circuit filling and smoothness can be easily achieved, it is preferable to perform a smoothing step as a separate step after the laminating step. In this case, the conditions for performing the smoothing step are preferably set as appropriate according to various conditions such as resin fluidity, substrate thickness, thermal conductivity due to the residual copper ratio, and uniformity in pressing. The heating temperature is preferably equal to or higher than the lamination temperature. The upper limit of the heating temperature is preferably 170 ° C. or lower in order to suppress the generation of voids due to the residual solvent. As with the heating temperature, the pressure is preferably set as appropriate according to various conditions such as resin fluidity, substrate thickness, thermal conductivity due to residual copper ratio, and pressure uniformity. In order to prevent deformation of the substrate due to pressure, the pressure is preferably 0.2 to 1.0 MPa. The heating / pressurizing time is preferably more than 10 seconds and less than 90 seconds in consideration of the balance between fluidity and productivity.

  When an insulator is used as the support, the support of the insulating resin with the support is removed as necessary after lamination, a conductor layer is formed thereon, and processed to form the second wiring. In the case where a conductor is used as the support, it is not necessary to remove the conductor because it is processed into a conductor layer of a second wiring to be subsequently formed.

  According to the present invention, a known method can be used in the step of (d) curing the insulating resin layer to form the insulating layer. This curing condition is preferably performed separately for preliminary curing and main curing.

  Pre-curing is preferably performed at a curing temperature of 40 to 80 ° C. lower than the main curing temperature for 10 to 90 minutes. The pre-curing temperature is 40 to 80 ° C. lower than the main curing temperature because of the flatness due to the progress of curing and the fluidity during the main curing, and the flatness due to the fluidity during the pre-curing. This is because of this balance. Flatness is that there are few unevenness | corrugations, such as a recessed part. The curing time is important to be 10 to 90 minutes considering the balance between the time required for curing and productivity.

  Following the preliminary curing, it is preferable to perform the main curing. The main curing is preferably performed at a temperature and time considering a plating process, a copper annealing process, and the like. Depending on the degree of curing, the adhesion to copper and the resistance to an alkali treatment solution are affected during the subsequent plating process. Considering these, for example, in the case of an epoxy resin-based insulating resin composition, it is preferable to cure by applying a heat treatment at 150 to 190 ° C. for about 30 to 90 minutes.

  After the insulating resin layer is cured, a via hole or the like can be formed in the insulating resin layer in order to connect the first wiring and the subsequently formed second wiring as needed. The via hole formation method is not particularly limited, and a known method such as a laser method or a sand blast method can be used.

  According to the present invention, (e) in the step of forming a second wiring on the insulating layer to produce a multilayer wiring board, the method, the insulating layer, and the wiring in the step (b) described above are described. Applies. Here, when a conductor is used as the support and the insulating resin layer is formed as an insulating resin layer with metal foil, the second wiring can be formed using an etching method.

  According to the present invention, after producing a multilayer wiring board, the above-described steps (c) to (e) can be repeated as necessary to obtain a multilayer wiring board having a larger number of layers. That is, the surface treatment of the second wiring can be performed in the same manner as the surface treatment of the first wiring. And it forms by laminating the same insulating resin with a support body produced at the process (a) on the wiring produced later. In the case where a via hole is formed in the first wiring, the second wiring, or a wiring subsequent thereto, it is preferable to perform a smoothing process for forming a smooth insulating layer. In this manner, an insulating layer is formed by lamination, and wiring is formed by the same method as the second wiring formation. By repeating these steps, a multilayer wiring board having a large number of layers can be produced.

  The multilayer wiring board according to the present invention is obtained by the above-described method for producing a multilayer wiring board according to the present invention, and the specific configuration such as the layer configuration and the circuit configuration is not particularly limited.

  In the method for producing a multilayer wiring board according to the present invention, as the insulating resin with a support, the melt viscosity at 40 ° C. when the temperature is applied to the insulating resin layer is 8000 to 50000 Pa · s, and the minimum melt viscosity is 10 to 10. The insulating resin with a support of 400 Pa · s is used, and the laminating temperature is 10 ° C. or more lower than the temperature showing the minimum melt viscosity of the insulating resin layer, and the pre-curing temperature is the main curing temperature. It is characterized in that it is carried out at a temperature lower by 40-80 ° C. for 10-90 minutes. Furthermore, a smoothing process can be arbitrarily performed. Thereby, the insulating resin with a support can be laminated on the wiring board very smoothly so that there is almost no step on the surface of the insulating resin layer. Here, the fact that there is almost no step means a state where the step is 2 μm or less, for example. The resulting multilayer wiring board has small surface irregularities, and therefore can greatly reduce resist chipping and resist follow-up due to steps, and as a result, is suitable for fine wiring properties. ing.

  Also, when there are non-through via holes such as through-holes, blind via holes, and buried via holes on the side where the insulating resin layer is laminated, through-through through by smoothing in addition to laminating. A smooth insulating layer having almost no step can be formed in the insulating resin layer immediately above the hole or the non-through via hole. Thereby, even when a wiring is formed immediately above the through-hole or the non-through-via hole, the followability of the resist is improved, and a wiring board suitable for fine wiring properties can be manufactured.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples without departing from the technical idea of the present invention.

Example 1
(1) Fabrication of wiring board Glass cloth base epoxy resin double-sided copper-clad laminate (MCL-E-67: Hitachi Chemical Co., Ltd. product name, copper foil thickness 18 μm, substrate thickness 0.8 mm, double-side roughened Etching was performed on both sides of the foil, and a wiring board having wiring (hereinafter referred to as first wiring) on one side was produced.

(2) Production of insulating resin with support A resin composition having the following composition was prepared.
・ O-cresol novolac type epoxy resin (YDCN-702: trade name, manufactured by Nippon Kayaku Co., Ltd.) 50 parts by weight ・ Bisphenol A type epoxy resin (DER-331: trade name, manufactured by Dow Chemical Co., Ltd.) 30 parts by weight ・ Carboxylic acid Modified acrylonitrile butadiene rubber (PNR-1H: trade name, manufactured by JSR Corporation) 10 parts by weight • Thermosetting agent: Dicyandiamide (trade name, manufactured by Nippon Carbide Corporation) 2.9 parts by weight • 1-cyanoethyl-2-phenylimidazolium tri Melitate (2PZ-CNS: trade name manufactured by Shikoku Chemicals Co., Ltd.) 0.4 parts by weight • Solvent: 40 parts by weight of methyl ethyl ketone • Solvent: 26 parts by weight of dimethylformamide Polyethylene having a thickness of 50 μm as a support Coat on terephthalate film and 3 The film was dried for 5 minutes to produce a film with an insulating resin in which the thickness of the insulating resin layer after drying was 50 ± 3 μm.

(3) Measurement of melt viscosity Only the insulating resin layer is taken out from the obtained insulating resin with a support and powdered. A predetermined amount of the powder was weighed, and a tablet-like sample having a diameter of 20 mm was produced with a tablet molding machine, and used as a measurement sample. The melt viscosity of this measurement sample was measured using a viscosity / elastic modulus measuring device (Rheometer ARES: trade name, manufactured by Rheometric Far East Co., Ltd.) under conditions of a temperature increase of 5 ° C./min, an excitation frequency of 1 Hz, and a room temperature to 200 ° C. did. From the obtained melt viscosity curve, the melt viscosity at 40 ° C. was 14046 Pa · s. The minimum melt viscosity was 105 Pa · s, and the temperature showing the minimum melt viscosity was 128 ° C.

(4) Manufacture of multilayer wiring board (4.1) The insulating resin with support of (2) above was laminated on the wiring board of (1) so that the insulating resin layer of the film was in contact with the wiring surface of the substrate. Lamination was performed at 100 ° C., 0.5 MPa · s, a vacuum time of 30 seconds, and a pressurization time of 30 seconds using a batch type vacuum pressure laminator (MVLP-500: trade name, manufactured by Meiki Seisakusho Co., Ltd.). Then, as a smoothing treatment immediately, a stainless steel plate having a thickness of 0.5 mm is placed on the outer support surface, and a batch type vacuum pressure laminator (MVLP-500: trade name, manufactured by Meiki Seisakusho Co., Ltd.) is used. , 120 ° C., 0.5 MPa · s, vacuum time 30 seconds, pressurization time 30 seconds. Thereafter, the support was peeled off, and the insulating resin layer was cured by curing at 170 ° C. for 60 minutes.
(4.2) For the obtained insulating resin layer (hereinafter referred to as the first insulating resin layer), a CO ₂ laser processing machine (LCO-1B21 type: product name manufactured by Hitachi Via Mechanics Co., Ltd.) is used, and the beam diameter Processing was performed under the conditions of 80 μm, frequency 500 Hz, pulse width 5 μsec, and number of shots 7 to produce via holes for interlayer connection.
(4.3) In order to chemically roughen the first insulating resin layer, an aqueous solution containing KMnO ₄ : 60 g / liter and NaOH: 40 g / liter was prepared as a roughening solution and heated to 70 ° C. The sample was immersed for 5 minutes. Subsequently, an aqueous solution containing SnCl ₂ : 30 g / liter and HCl: 300 ml / liter was used as a neutralizing solution, and the sample was neutralized by immersion for 5 minutes at room temperature to obtain a roughened sample.
(4.4) In order to form the second wiring on the surface of the first insulating resin layer, first, the surface-roughened sample was subjected to electroless plating catalyst solution containing PdCl ₂ (HS-202B: Hitachi Chemical Co., Ltd.). (Product name) manufactured for 10 minutes at room temperature. The sample after immersion was washed with water, immersed in an electroless copper plating solution (CUST-201: trade name, manufactured by Hitachi Chemical Co., Ltd.) for 15 minutes at room temperature, and further subjected to copper sulfate electrolytic plating. After plating, annealing was performed at 170 ° C. for 60 minutes to form a wiring conductor layer having a thickness of 20 μm on the surface of the first insulating resin layer.
Next, in order to remove unnecessary portions of the obtained wiring conductor layer by etching, the oxide film on the copper surface was removed by # 600 buffalo polishing, and then an etching resist layer was formed and etched. Thereafter, the etching resist layer was removed, and a second wiring including a via hole connected to the first wiring was formed.

(5) Next, the same insulating resin with a support as that used to form the first wiring is placed on the side where the insulating resin layer is in contact with the wiring layer. Using a batch type vacuum pressurization laminator (MVLP-500: trade name, manufactured by Meiki Seisakusho Co., Ltd.) as a laminate on this insulating resin layer, 100 ° C., 0.5 MPa · s, vacuum time 30 seconds, pressurization time 30 Laminated in seconds. Then, as a smoothing treatment immediately, a stainless steel plate having a thickness of 0.5 mm is placed on the outer support surface, and a batch type vacuum pressure laminator (MVLP-500: trade name, manufactured by Meiki Seisakusho Co., Ltd.) is used. , 120 ° C., 0.5 MPa · s, vacuum time 30 seconds, pressurization time 30 seconds. Thereafter, the support was peeled off, and the insulating resin layer was cured by curing at 170 ° C. for 60 minutes.
(6) A multilayer wiring board was manufactured by forming wiring on the second insulating layer by the same method as the steps (4) to (5).

Example 2
Using the insulating resin with support of Example 1, preliminary curing was performed at 100 ° C. for 30 minutes, and then main curing was performed at 170 ° C. for 60 minutes. Others were the same as in Example 1.

Comparative Example 1
The insulating resin with a support of Example 1 was stored at 25 ° C. for 2 weeks. From the melt viscosity curve of the obtained insulating resin with a support, the melt viscosity at 40 ° C. was 56557 Pa · s. The minimum melt viscosity was 361 Pa · s, and the temperature at which the minimum melt viscosity was exhibited was 133 ° C. Others were the same as in Example 1.

Comparative Example 2
The insulating resin with a support of Example 1 was stored at 5 ° C. for 2 months, and the melt viscosity at 40 ° C. of the obtained insulating resin with a support was 23757 Pa · s. The minimum melt viscosity was 426 Pa · s, and the temperature showing the minimum melt viscosity was 153 ° C. Others were the same as in Example 1.

Comparative Example 3
The insulating resin with a support of Example 1 was stored at 25 ° C. for 2 weeks. From the melt viscosity curve of the obtained insulating resin with a support, the melt viscosity at 40 ° C. was 56557 Pa · s. The minimum melt viscosity was 361 Pa · s, and the temperature at which the minimum melt viscosity was exhibited was 133 ° C. Others were the same as in Example 2.

  About the multilayer wiring board produced as mentioned above, the surface roughness immediately after insulating resin layer formation and insulating resin layer hardening was measured. The results are shown in Table 1.

As is apparent from Table 1, by using the method of the present invention, it is possible to efficiently produce a multilayer wiring board that has excellent surface flatness of 2.0 μm or less and is suitable for miniaturization. is there.
On the other hand, in Comparative Example 1, the melt viscosity at 40 ° C. was outside the range of the present invention, and the surface unevenness after curing the insulating layer was as large as 7.0 μm.
In Comparative Example 2, the minimum melt viscosity was outside the range of the present invention, and the surface unevenness after curing of the insulating layer was as large as 8.4 μm.
In Comparative Example 3, the melt viscosity at 40 ° C. was outside the range of the present invention, and the surface unevenness after curing the insulating layer was as large as 6.2 μm.

  According to the multilayer wiring board or the manufacturing method of the multilayer wiring board of the present invention, it is possible to simply provide a multilayer wiring board having few surface irregularities and excellent flatness and suitable for miniaturization.

1A to 1G are cross-sectional views illustrating a process for manufacturing a multilayer wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulation resin with support body 2 Wiring board 3 Laminate board 11 Support body 12 Insulation resin layer 21 Board | substrate 22a 1st wiring (inner layer circuit)
22b Second wiring (inner layer circuit or outer layer circuit)
23c Third wiring (inner layer circuit or outer layer circuit)

Claims (18)

A multilayer wiring board produced by laminating an insulating resin with a support, with an insulating resin layer deposited on the support, so as to face the wiring formed on the substrate or the wiring board,
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
A multilayer wiring board, wherein the laminating step is performed at a temperature lower by 10 ° C. or more than a temperature indicating a minimum melt viscosity of the insulating resin layer. A method of manufacturing a multilayer wiring board,
(A) attaching an insulating resin on an insulating support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the surface having the first wiring of the substrate covers the insulating resin layer, and removing the insulating support;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring on the insulating layer to produce a multilayer wiring board;
Including
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
A method for producing a multilayer wiring board, wherein the laminating step (c) is performed at a temperature lower by 10 ° C. or more than a temperature showing a minimum melt viscosity of an insulating resin layer.   The multilayer wiring board according to claim 2, wherein in the curing step (d), a main curing step is performed after the preliminary curing step, and the preliminary curing step is performed at a temperature lower by 40 to 80 ° C than the main curing temperature for 10 to 90 minutes. Manufacturing method.   The step of (f) forming a penetration or non-penetration electrical connection hole in the insulating layer is performed after the curing step (d) and before the second wiring formation step (e). A method for producing a multilayer wiring board according to 2 or 3.   In the said lamination process (c), it heats and presses with a rigid high plate so that it may oppose the support body surface of the said insulating resin with a support body, The smoothing process process is performed simultaneously. A method for producing a multilayer wiring board according to item 1.   After the laminating step (c) and before the curing of the insulating resin layer and the step of forming the resin layer (d), a rigid plate is used so as to face the support surface of the insulating resin with support. The manufacturing method of the multilayer wiring board of any one of Claims 2-5 which heats and pressurizes and performs a smoothing process.   In the step (a) for producing the insulating resin with a support, an insulating resin composition is applied to a thickness of 20 to 100 μm on a support having a thickness of 10 to 100 μm and dried to produce an insulating resin with a support. The manufacturing method of the multilayer wiring board of any one of Claims 2-6 which is a process to perform.   The method for producing a multilayer wiring board according to any one of claims 2 to 7, wherein the insulating resin composition is a resin composition that decreases in viscosity once by heating and then increases in viscosity.   The method for manufacturing a wiring board according to claim 2, wherein a resin composition containing an epoxy resin and cyanoethylated imidazole is used as the insulating resin composition. A method of manufacturing a multilayer wiring board,
(A) attaching an insulating resin on a support to produce an insulating resin with a support;
(B) forming a first wiring on one side or both sides of the substrate to produce a single-sided or double-sided wiring board;
(C) laminating the insulating resin with a support on the substrate so that the insulating resin layer covers the surface of the substrate having the first wiring;
(D) curing the insulating resin layer to form an insulating layer;
(E) forming a second wiring to produce a multilayer wiring board;
Including
As the insulating resin layer, using a thermosetting insulating resin composition having a melt viscosity at 40 ° C. of 8000 to 50000 Pa · s and a minimum melt viscosity of 10 to 400 Pa · s,
In the insulating resin-preparing step (a) with a support, a conductor is used as a support,
The laminating step (c) is performed at a temperature lower by 10 ° C. or more than the temperature indicating the minimum melt viscosity of the insulating resin layer,
In the second wiring formation and multilayer wiring board manufacturing step (e), the second wiring is formed by processing the support.   The multilayer wiring board according to claim 10, wherein in the curing step (d), a main curing step is performed after the preliminary curing step, and the preliminary curing step is performed at a temperature lower by 40 to 80 ° C than the main curing temperature for 10 to 90 minutes. Manufacturing method.   The step of (f) forming a penetration or non-penetration electrical connection hole in the insulating layer is performed after the curing step (d) and before the second wiring formation step (e). The manufacturing method of the multilayer wiring board of 10 or 11.   In the said lamination process (c), it heats and presses with a rigid high plate so that it may oppose the support body surface of the said insulating resin with a support body, The smoothing process process is performed simultaneously. A method for producing a multilayer wiring board according to item 1.   After the laminating step (c) and before the curing of the insulating resin layer and the step of forming the resin layer (d), a rigid plate is used so as to face the support surface of the insulating resin with support. The manufacturing method of the multilayer wiring board of any one of Claims 10-13 which performs a smoothing process by heating and pressurizing.   In the step (a) for producing the insulating resin with a support, an insulating resin composition is applied to a thickness of 20 to 100 μm on a support having a thickness of 10 to 100 μm and dried to produce an insulating resin with a support. The manufacturing method of the multilayer wiring board of any one of Claims 10-14 which is a process to carry out.   The method for producing a multilayer wiring board according to any one of claims 10 to 15, wherein the insulating resin composition is a resin composition that decreases in viscosity once by heating and then increases in viscosity.   The method for manufacturing a wiring board according to any one of claims 10 to 16, wherein a resin composition containing an epoxy resin and cyanoethylated imidazole is used as the insulating resin composition. The multilayer wiring board manufactured by the method of any one of Claims 1-17.

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