JP2013138124A - Multilayer printed board manufacturing method, multilayer printed board manufactured by the manufacturing method, and curable resin composition used in the manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer printed board manufacturing method which, by dispensing with a stopgap surface polishing process, cuts down polishing costs and shortens the manufacturing process, making it possible to avoid deforming (dimensionally changing) the board or shaving it down to copper foil by polishing, and which forms external layers collectively in a heating and pressurization process to simplify the process.SOLUTION: The multilayer printed board manufacturing method includes a process in which a curable resin composition is filled in a through hole of a double sided or a multilayer board, and the surface of the curable resin composition is flattened by a method other than polishing before it is cured. In a more concrete preferable embodiment, a process of curing the curable resin composition filled in a hole and a process of laminating a prepreg or dry film type insulation material and/or resin-fitted metal foil one on another and then forming it into shape by heating and compression are executed in that order after the filling and flattening process.

Description

  The present invention provides the surface of the filled portion after curing by flattening the filling portion of the curable resin composition filled in the through-holes such as the double-sided board of the printed wiring board and the through-hole of the multilayer substrate before curing. Eliminates the polishing process and avoids deformation of the substrate (dimensional change) due to polishing and scraping of copper foil. Simplify the process by forming the outer layer all at once in the heating and pressurizing processes such as press molding. The present invention relates to a method for manufacturing a multilayer printed wiring board that can be manufactured. Furthermore, this invention relates to the multilayer printed wiring board manufactured by such a manufacturing method, and the curable resin composition used suitably for such a manufacturing method.

  In recent years, with the miniaturization and high functionality of electronic devices, there is a demand for miniaturization of printed wiring board patterns, reduction of mounting area, and high density of component mounting. Therefore, a double-sided board provided with a through hole, or a multilayer board such as a build-up wiring board in which an insulating layer and a conductor circuit are sequentially formed on a core material and are connected in layers by via holes or the like are used. Then, area array mounting such as BGA (ball grid array) and LGA (land grid array) is performed.

  In such a printed wiring board, the concave portions between the conductor circuits on the surface, and the holes such as through holes and via holes in which the conductive layer is formed on the inner wall surface are filled with the thermosetting resin composition by a printing method or the like. The In general, thermosetting epoxy resin compositions are widely used as permanent hole filling compositions for printed wiring boards because their cured products have excellent mechanical, electrical, and chemical properties and good adhesion. It has been. In general, the permanent hole filling of a printed wiring board using such an epoxy resin composition is performed by plating an insulating substrate 11 on which a conductor pattern 12 is formed as shown in FIG. 2A, for example, as shown in FIG. A step of filling the through-hole 13 with an epoxy resin composition (the state shown in FIG. 2 (B)), a step of pre-curing the filled composition to a polishable state, and a pre-cured composition From the step of polishing and removing the portion protruding from the surface of the hole by buffing or the like (the state shown in FIG. 2C), and the step of further heating and pre-curing (pre-curing) the precured composition Then, a copper foil with resin 15 in which a curable resin 17 made of an epoxy resin composition is bonded to the copper foil 16 is laminated to form a double-sided copper-clad laminate (state shown in FIG. 2D), Next The copper foil 16 patterned etched to form an outer layer conductor pattern 18 method (the state shown in FIG. 2 (E)) is generally employed.

However, according to such a method, there is a problem in that the substrate is deformed (dimensional change) due to polishing and a situation where the copper foil is scraped off is caused.
In order to solve such a problem, Japanese Patent Application Laid-Open No. 2007-49106 (Patent Document 1) discloses that a photo / thermosetting resin composition is applied to one surface and a through hole of a printed wiring board having a through hole. (1) The step of flattening the surface of the coating resin with a pressure roll and (2) the step of photocuring the coating resin are sequentially performed, and then the photo / thermosetting resin composition is applied to the other side of the printed wiring board A method for producing a multilayer printed wiring board is characterized in that after the steps (1) and (2) are sequentially performed, the resin composition is thermally cured and completely cured. Proposed.

Japanese Patent Laid-Open No. 2006-303398 (Patent Document 2) describes a method of filling a through-hole of a double-sided printed wiring board with a two-stage curable resin composition, and heating the resin at 100 to 200 ° C. or UV irradiation. First stage curing is performed, and then the double-sided printed wiring board is sandwiched between (a) a copper foil with resin and a copper foil with resin, or (b) a copper foil with resin and a prepreg, and the second stage curing temperature or higher. A method for manufacturing a hole-filled multilayer printed wiring board is proposed, in which a conductor pattern is formed on a surface copper foil by an etching method after laminating and pressing.
However, none of the above-described methods scrapes off the portion of the curable resin composition filled in the hole from the surface of the hole, so that the resin composition remains other than the hole-filled portion. There is a problem that it is difficult to adjust the flatness of the film and that the subsequent laser processability and desmear resistance are inferior.

  Furthermore, Japanese Patent Application Laid-Open No. 2007-235121 (Patent Document 3) discloses that a non-contact roll and a doctor having a reversing mechanism are linearly moved in a horizontal direction with respect to the substrate surface, and a hole portion of the substrate disposed in the vacuum chamber. A step (a) of forming a resin layer on at least the hole, and a step (b) of removing the resin layer by reversing the non-contact roll and doctor and moving them linearly in the opposite direction. There has been proposed a method for manufacturing a resin-filled substrate characterized by including: However, this method is a coating operation in a vacuum, and is a method in which an adhesive PET film is stretched on the back surface of the substrate to make a pseudo bottomed via state, and the resin is filled by rotating the roller portion. Since the lower end portion of the through hole is closed by the PET film, there is no problem of bubbles escaping and bubbles are generated. In addition, as for the surface state after coating and curing, the printed surface and the film surface are dented due to the curing shrinkage of the resin (the film peeling is performed after the resin paste is cured), and this dent was laminated and pressed with a prepreg or the like. Sometimes it causes delamination. Moreover, the occurrence of this delamination leads to poor solder heat resistance. Furthermore, since the vacuum is not completely filled when filling the hole-filling resin, there is a problem in that a portion with poor fillability is generated at the bottom portion, which causes bubbles to be generated.

  Conventionally, when filling a hole such as a through hole or a via hole in a printed board with a curable resin composition, it is filled under conditions suitable for the diameter (ink viscosity, TI value, printing conditions, etc.). The In general, the diameter of a through hole or the like in one substrate is often the same. Therefore, it is usually possible to adapt to the size of the diameter by adjusting the viscosity or TI value of the curable resin composition or adjusting the printing conditions (squeegee speed, angle, printing pressure, etc.).

  However, with the recent increase in the density of printed circuit boards, the diameters of through holes and the like are also miniaturized. A drill, a carbon dioxide laser, or the like is used to form the through hole. However, as the diameter of the through hole is reduced, the processing cost increases greatly. For this reason, as a means for keeping the processing cost low, a substrate is produced in which only a portion that must be very small has a small diameter and the other portions are processed with a large diameter. That is, there are a plurality of through holes having different diameters in one printed circuit board. In this case, the processing cost of the substrate (creation of the through hole) can be kept low as intended, but filling of the curable resin composition becomes very difficult. This is because it is difficult to appropriately fill a plurality of through holes having different diameters by one printing. As a result, in spite of the objective of keeping the manufacturing cost of the substrate low, the manufacturing cost cannot be kept low due to the difficulty in filling the curable resin composition, and it may be increased. Furthermore, the current situation is that the difficulty in filling the curable resin composition has an adverse effect on the quality of the substrate.

That is, when printing is performed under a printing condition suitable for a through hole having a small diameter by one printing, the through hole having a small diameter suitable for the printing condition is appropriately filled. However, since the through hole having a large diameter that does not meet the printing conditions is excessively filled with the curable resin composition, the protruding portion of the curable resin composition on the side opposite to the printing surface excessively protrudes. . On the other hand, when printing is performed under printing conditions suitable for a large-diameter through-hole, the large-diameter through-hole suitable for the printing condition is appropriately filled. However, because the through hole with a small diameter does not meet the printing conditions, the curable resin composition is not sufficiently filled to the bottom, and an unfilled portion of the curable resin composition may occur in the through hole. There is. Alternatively, even when the through hole is completely filled, the amount of the protruding portion is smaller than that of the large diameter through hole. In other words, the amount of protrusion varies depending on the diameter of the through hole.
Thus, another problem arises because the amount of protrusion differs. That is, the curable resin composition is generally subjected to buffing or the like after filling and curing, thereby polishing the portion protruding from the through hole and flattening the surface of the substrate. Has a disadvantage in terms of cost because the time required for polishing becomes longer. In addition, when the polishing time is too long or the protruding amount is different, the surface of the substrate other than the protruding portion may be damaged by polishing, the size may be changed, and the substrate may be distorted.

  In order to solve such a problem, a method of printing a plurality of times according to the number of diameters can be considered. For example, in the case of a substrate having a plurality of through holes having different diameters such as diameters A, B,..., A screen printing plate (dot pattern) suitable for the size and arrangement of the diameter A is prepared and set. Filling is performed under printing conditions suitable for the diameter A. Next, a plate (dot pattern) corresponding to the diameter B is set, and filling is performed under printing conditions suitable for the diameter B. This is repeated for the number of diameters. This filling method can solve the quality problem, but has a problem that filling takes much time and the purpose of reducing the processing cost cannot be achieved.

JP 2007-49106 A (Claims, FIG. 1) JP 2006-303398 A (Claims, FIG. 1) JP 2007-235121 A (Claims, FIGS. 4 to 8)

The present invention has been made in view of the circumstances as described above, and its main purpose is to reduce the polishing cost by omitting the polishing process of the hole filling surface, to shorten the manufacturing process, and to deform the substrate by polishing ( Dimensional change) and the situation of scraping to copper foil can be avoided, and a method for manufacturing a multilayer printed wiring board that can simplify the process by forming the outer layer at once by heating and pressing processes such as press molding is provided. There is to do.
Another object of the present invention is to provide a method for producing a multilayer printed wiring board that can be appropriately filled with a single printing even on a substrate having a plurality of through holes such as through holes having different diameters. There is to do.
Furthermore, an object of the present invention is to provide a method capable of producing a printed wiring board that is free of bubbles, has excellent substrate flatness, laser processability, and desmear resistance, and also has excellent characteristics such as solder heat resistance. It is in.
Another object of the present invention is to provide a printed wiring board that is manufactured by such a manufacturing method and has excellent characteristics, and a curable resin composition that can be suitably used for such a manufacturing method. .

In order to achieve the above object, according to the present invention, the curable resin composition is filled into the double-sided board of the printed wiring board or the through hole of the multilayer board, and the curable resin composition is cured before being cured. The manufacturing method of the multilayer printed wiring board characterized by including the process of planarizing the surface of a conductive resin composition by methods other than grinding | polishing is provided.
In a preferred aspect, the through holes are a plurality of through holes having the same diameter and / or a plurality of different diameters. Moreover, in another suitable aspect, the said planarization process is performed by scraping the part which the said curable resin composition protrudes from the said through-hole surface using a doctor.

The method for producing a multilayer printed wiring board of the present invention is, in a more specific preferred embodiment, (a) a step of filling a curable resin composition into a double-sided board of a printed wiring board or a through hole of a multilayer board,
(B) a step of flattening the surface of the curable resin composition filled in the hole by a physical method other than polishing,
(C) a step of curing the curable resin composition filled in the hole, and (d) a step of laminating a prepreg or dry film type insulating material and / or metal foil with resin, and molding by heating and pressing. These steps are performed in the above order.
In a preferred embodiment, the step (b) is performed by scraping with a doctor or film transfer to remove the portion of the curable resin composition filled in the hole from the surface of the hole, thereby flattening the surface of the substrate. Turn into.

  Furthermore, according to the present invention, there is provided a multilayer printed wiring board produced by the production method, and the curable resin composition is a thermosetting resin composition or a photocurable thermosetting. There is also provided a curable resin composition which is a curable resin composition and is used in the method for producing a multilayer printed wiring board.

As described above, the method for producing a multilayer printed wiring board according to the present invention cures flattening of a filling portion of a curable resin composition filled in a through hole such as a double-sided board of a printed wiring board or a through hole of a multilayer board. By performing before, it is possible to omit the polishing process of the surface of the filled portion after curing, avoid the deformation (dimension change) of the substrate due to polishing, the situation of scraping to the copper foil, etc., and further generate distortion in the substrate In addition, after curing, a prepreg or dry film type insulating material and / or metal foil with resin can be laminated and heated and pressed by, for example, press molding to form an outer layer at one time. Can simplify the process.
Further, by flattening the filling portion of the curable resin composition before curing, the substrate having through holes such as a plurality of through holes having different diameters is appropriately filled by one printing. be able to. In other words, unlike the conventional case, filling is performed under printing conditions suitable for through holes such as through holes with a small diameter that are most difficult to fill without worrying about the difference in the amount of the portion protruding from the hole after filling. Thus, the curable resin composition can be filled with one printing without generating an unfilled portion.
In addition, by using the method for producing a multilayer printed wiring board of the present invention, there is no generation of bubbles, and the printed circuit board has excellent substrate flatness, laser workability, desmear resistance, and excellent characteristics such as solder heat resistance. A wiring board can be manufactured with high productivity.

It is a schematic explanatory drawing which shows an example of the manufacturing process of the multilayer printed wiring board which concerns on this invention. It is a schematic explanatory drawing which shows the manufacturing process of the multilayer printed wiring board which grind | polishes the filling part surface after the conventional preliminary hardening. The surface of the light / thermosetting resin composition applied to one surface of the printed wiring board and the through-hole of Comparative Example 1 was sequentially subjected to flattening with a pressure roll and photocuring, and then the other surface. It is a schematic explanatory drawing which shows the manufacturing process of the multilayer printed wiring board which heat-resists the resin composition after performing similarly. In Comparative Example 2, the double-sided printed wiring board after the first stage curing of the two-stage curable resin composition filled in the through hole is sandwiched between the resin-coated copper foil and the resin-coated copper foil, and the second stage It is a schematic explanatory drawing which shows the manufacturing process of the multilayer printed wiring board which performs a lamination press above a curing temperature. The non-contact roll and doctor having the reversing mechanism of Comparative Example 3 are linearly moved in the horizontal direction with respect to the substrate surface, and the resin paste is filled in the hole portion of the substrate arranged in the vacuum chamber, and at least above the hole portion. The outline which shows the manufacturing process of the multilayer printed wiring board including the process (a) which forms a resin layer in (a), and the process (b) which reverses a non-contact roll and a doctor, and moves linearly to a reverse direction and removes a resin layer It is explanatory drawing.

As described above, in the method for producing a multilayer printed wiring board of the present invention, the curable resin composition is filled in the double-sided board of the printed wiring board or the through hole of the multilayer board, and before the curable resin composition is cured. The method further comprises a step of planarizing the surface of the curable resin composition by a method other than polishing. In a more specific preferred embodiment,
(A) filling a curable resin composition into a double-sided board of a printed wiring board or a through-hole of a multilayer board;
(B) a step of flattening the surface of the curable resin composition filled in the hole by a physical method other than polishing,
(C) a step of curing the curable resin composition filled in the hole, and (d) a step of laminating a prepreg or dry film type insulating material and / or metal foil with resin, and molding by heating and pressing. Performing the above steps in the above order, that is, performing the planarization of the filling portion of the curable resin composition filled in the through holes such as the double-sided board of the printed wiring board and the through-hole of the multilayer board before curing, And after hardening, it is characterized by laminating a prepreg or dry film type insulating material and / or a metal foil with resin, and performing a heating and pressurizing process, for example, by press molding or the like to form an outer layer at once. If attention is paid to bubble removal, the concave portion of the printed wiring board can be filled. Hereinafter, a method for producing a multilayer printed wiring board according to the present invention will be described in detail with reference to the accompanying drawings.

  First, for example, pattern etching is performed on a conductive layer of a double-sided printed wiring board having through holes, and a substrate 1 on which a conductor pattern 2 is formed as shown in FIG. 1A is prepared by a conventionally known method. The through holes include all kinds of holes penetrating through the printed wiring board, and specifically include through holes, through via holes, component holes, and the like. Examples of the double-sided printed wiring board include a rigid printed wiring board, a flexible printed wiring board, and a rigid / flex printed wiring board. In addition, the double-sided printed wiring board having a through hole is preferably one in which the surface of the conductive layer is roughened in order to improve the adhesion between the conductive layer and the resin layer. As the roughening treatment, blackening treatment, so-called CZ (chemical roughening agent manufactured by Mech Etch Bond), blackening reduction treatment, acicular alloy plating, physical treatment (sand blasting, shot blasting, buffing, etc.) Is mentioned.

  As a specific example of manufacturing the substrate 1 on which the conductor pattern 2 is formed, for example, a through-hole is drilled in a substrate laminated with a copper foil, and electroless plating is applied to the wall surface of the through-hole and the copper foil surface to form a through-hole. 3 is formed. As the substrate, a glass epoxy substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a fluororesin substrate or other resin substrate, a copper-clad laminate of these resin substrates, a ceramic substrate, or the like can be used. In the case of a substrate with poor plating, such as a fluororesin substrate, surface modification such as a pretreatment agent made of organometallic sodium or plasma treatment is performed. Next, electrolytic plating is performed for thickening, a plating film is formed on the substrate surface and the inner wall of the through hole, and then the substrate 1 on which the conductor pattern 2 is formed by pattern etching as shown in FIG. obtain. Copper plating is preferable as the electrolytic plating. Although FIG. 1A shows an example using a double-sided printed wiring board, it is needless to say that a multilayer board may be used.

(A) Step of filling the through hole of the substrate with the curable resin composition The plated through hole 3 of the substrate 1 as described above, for example, is filled with the curable resin composition 4 and shown in FIG. The state is as follows. The filling step (a) is performed, for example, by a squeegee printing method or a roll coating method, preferably by screen printing with a dot pattern.
In the case of a substrate having through holes such as a plurality of through holes having different diameters, for example, filling is performed under printing conditions suitable for the through hole having the smallest diameter that is most difficult to fill. As a result, it is possible to perform printing under the condition that a through hole of any size is filled to the bottom without generating an unfilled portion by one printing. Further, unlike the conventional method, filling can be performed without worrying about the difference in the amount of protrusion from the hole.

(B) Step of flattening the surface of the curable resin composition filled in the hole by a physical method other than polishing Next, the portion of the curable resin composition protruding from the surface of the hole is physically removed by polishing. Curable resin composition by transferring the portion protruding from the surface of the hole portion of the filled curable resin composition to the support film using a method such as scratching with a doctor or using a support film and a roll laminator The portion protruding from the surface of the hole is removed, and the surface of the substrate 1 is flattened as shown in FIG. When using a doctor, it is preferable to carry out by making the front-end | tip part of a doctor contact a substrate surface. In this case, the part which protrudes from the hole part surface of the curable resin composition with which it filled can be removed by moving a doctor linearly with respect to a board | substrate surface. At this stage of the process, since the curable resin composition has not been cured yet, the protruding portion protruding from the hole surface can be easily removed.
In the case of a substrate having a plurality of through-holes such as through-holes having different diameters, the protruding amount of the protruding part generated on the opposite side of the printing surface is different depending on the size of the diameter (large diameter part The amount of protrusion is large, and the amount of protrusion is small in the small diameter part.) However, by scratching the protruding part from the surface of the substrate by a method such as transfer to a squeegee or film before curing, The surface of the substrate is flattened without damaging the surface of the substrate, changing the dimensions, or causing distortion of the substrate.

(C) Step of curing the curable resin composition filled in the hole Next, the curable resin composition filled in the hole is cured. Curing may be selected according to the type of curable resin composition used. For example, when a thermosetting resin composition is used as the curable resin composition, it is heated to about 100 ° C. to 200 ° C. In addition, when a photocurable thermosetting resin composition is used, it is performed by irradiation with active energy rays, and the filled curable resin composition is semi-cured or main-cured. Although this hardening can also be made into the state which carried out complete hardening (main hardening) of the curable resin composition, Preferably it is set as the semi-hardened state. For example, when an epoxy resin composition is used as the thermosetting resin composition, it is heated to about 100 ° C. to 130 ° C. so that the epoxy reaction rate becomes about 80% to 97%. When the thermosetting resin composition is used, the irradiation amount of the active energy ray is adjusted so that the photoreaction rate of the ethylenically unsaturated double bond is about 80% to 97%. Also, multi-stage curing can be performed in order to reliably remove bubbles and to easily suppress the residual voids and the occurrence of cracks during curing.

(D) A step of laminating a prepreg or dry film type insulating material and / or a metal foil with resin, and molding by heating and pressing As described above, a curable resin composition in a semi-cured or fully cured state in the hole portion A prepreg or dry film type insulating material and / or metal foil with resin is laminated on both surfaces (or one surface) of the substrate 1 filled with 4 and integrated by heating and pressing. For example, a copper foil 6 with a resin in which a curable resin composition 7 such as an epoxy resin composition is bonded to a copper foil 6 is laminated to form a double-sided copper-clad laminate, and heated and pressed, and FIG. ).

  Next, an etching resist is formed on the surface of the obtained double-sided copper-clad laminate, and the copper foil 6 is pattern-etched by etching the non-resist-formed portion, and as shown in FIG. Pattern 8 is formed. Furthermore, a multilayer printed wiring board can be manufactured by repeating the above-mentioned process.

  As described above, as the curable resin composition filled in the through-holes such as the double-sided board of the printed wiring board and the through-hole of the multilayer board, the thermosetting resin composition and the photocurable thermosetting resin composition are used. Although it can be used, the viscosity is preferably 100 dPa · s or more and 1000 dPa · s or less at 25 ± 1 ° C. Various thermosetting resin compositions can be used as the thermosetting resin composition, but the epoxy resin is excellent in that the cured product has excellent mechanical, electrical and chemical properties and good adhesiveness. Compositions are preferred. The epoxy resin composition contains an epoxy resin and an epoxy resin curing agent, and is blended with other components such as a filler as necessary. The photocurable thermosetting resin composition is in addition to these components. Further, a photocurable component and a radical photopolymerization initiator are blended.

  As an epoxy resin used for the said curable resin composition, what has a 2 or more epoxy group in 1 molecule should just be used, and a well-known thing can be used. For example, bisphenol A type epoxy resin, bisphenol S type epoxy resin, dinaphthol type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, alicyclic epoxy resin, polyethylene glycol or polypropylene glycol diester Glycidyl ether, polytetramethylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, phenyl-1,3-diglycidyl ether, biphenyl-4,4′-diglycidyl ether, 1,6-hexanediol Diglycidyl ether, diglycidyl ether of ethylene glycol or propylene glycol, sorbitol polyglycidyl ether, Compounds having two or more epoxy groups in one molecule such as rubitan polyglycidyl ether, tris (2,3-epoxypropyl) isocyanurate, triglycidyltris (2-hydroxyethyl) isocyanurate, tetraglycidylaminodiphenylmethane Amine type epoxy resins such as tetraglycidyl metaxylylene diamine, triglycidyl paraaminophenol, diglycidyl aniline, diglycidyl orthotoluidine, etc., and epoxy resins that are liquid at room temperature, for example, 20 ° C. are preferred.

  These commercially available products include bisphenol A type liquid epoxy resin, jER828 manufactured by Mitsubishi Chemical Corporation, YD128 manufactured by Nippon Steel Chemical Co., Ltd., and bisphenol F type liquid epoxy resin, jER807 manufactured by Mitsubishi Chemical Corporation, YDF manufactured by Nippon Steel Chemical Co., Ltd. -170, as a phenol novolac type epoxy resin, DEN431 manufactured by Dow Chemical Company, as an amine type liquid epoxy resin (paraaminophenol type liquid epoxy resin), jER-630 manufactured by Mitsubishi Chemical Corporation, ELM-100 manufactured by Sumitomo Chemical Co., Ltd., Huntsman Examples include MY0510 manufactured by Advantest Materials.

Among these, when the paste has a low viscosity, the amount of the inorganic filler can be increased, and a liquid epoxy resin containing a benzene ring which is a heat-resistant skeleton is preferable.
The epoxy resins as described above can be used alone or in combination of two or more. The blending ratio of the epoxy resin varies depending on whether the composition is a thermosetting resin composition or a photocurable thermosetting resin composition, but generally 5% by mass or more and 70% by mass or less in the solid content of the composition. More preferably, 10 mass% or more and 60 mass% or less are suitable.

  The epoxy resin curing agent is used for curing the epoxy resin. Any epoxy resin curing agent can be used as long as it has an effect of accelerating the curing reaction of the epoxy resin, and is not limited to a specific one, but imidazole derivatives are preferable, for example, 2-methylimidazole, 4-methyl- 2-ethylimidazole, 2-phenylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethylimidazole, 2-isopropylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl Examples include 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-undecylimidazole. Specific examples of commercially available products include imidazoles such as trade names 2E4MZ, C11Z, C17Z, and 2PZ, and AZ INE compounds of imidazoles such as trade names 2MZ-A and 2E4MZ-A, trade names 2MZ-OK, and 2PZ-. Examples thereof include isocyanurate of imidazole such as OK, and imidazole hydroxymethyl compounds such as trade names 2PHZ and 2P4MHZ (the trade names are all manufactured by Shikoku Kasei Kogyo Co., Ltd.).

  Besides imidazole, dicyandiamide and its derivatives, melamine and its derivatives, diaminomaleonitrile and its derivatives, diethylenetriamine, triethylenetetramine, tetramethylenepentamine, bis (hexamethylene) triamine, triethanolamine, diaminodiphenylmethane, organic acid Amines such as hydrazide, 1,8-diazabicyclo [5.4.0] undecene-7 (trade name DBU, manufactured by San Apro), 3,9-bis (3-aminopropyl) -2,4,8 , 10-tetraoxaspiro [5.5] undecane (trade name ATU, manufactured by Ajinomoto Co., Inc.) or organic phosphine compounds such as triphenylphosphine, tricyclohexylphosphine, tributylphosphine, and methyldiphenylphosphine alone Or two It can be used in combination with the above. Among these curing catalysts, dicyandiamide, melamine, acetoguanamine, benzoguanamine, 3,9-bis [2- (3,5-diamino-2,4,6-triazaphenyl) ethyl] -2,4,8 , 10-tetraoxaspiro [5.5] undecane and derivatives thereof, and their organic acid salts and epoxy adducts are known to have adhesion and rust prevention properties with copper. In addition to acting as a curing catalyst for the resin, it can contribute to the prevention of discoloration of copper in the printed wiring board.

  In addition, the modified aliphatic polyamine and the modified alicyclic polyamine act as a curing agent for the epoxy resin. When mixed with the epoxy resin, the modified aliphatic polyamine and the modified alicyclic polyamine can be used as a one-component resin composition after mixing, and are one-component. However, it can be stored at room temperature for a long time (long pot life). For example, it can be stored at 25 ° C. for 180 days or longer without gelation, has excellent storage stability at room temperature, and has toxicity and skin properties. This is preferable from the viewpoint of less irritation and improved workability. In addition, compared with other amine-based curing agents such as dicyandiamide and its derivatives, and amine compounds such as boron trifluoride-amine complex, the curing reaction starts at a relatively low temperature, and has high heat resistance and water resistance. Can be manufactured.

  Further, according to the study by the present inventors, as an epoxy resin curing agent, in combination with at least one selected from the group consisting of the above-mentioned modified aliphatic polyamine and modified alicyclic polyamine, further amine compounds, particularly dicyandiamide In the case of the thermosetting resin composition used in combination, since the viscosity increase rate during storage at room temperature can be suppressed, it can be stored for a longer period of time, and it can be cured even with a small amount of polyamine. The amount of polyamine and modified alicyclic polyamine used can be reduced.

  The polyamine-based curing agent is an adduct compound of an aliphatic polyamine such as an alkylene diamine having 2 to 6 carbon atoms, a polyalkylene polyamine having 2 to 6 carbon atoms, or an aromatic ring-containing aliphatic polyamine having 8 to 15 carbon atoms. Or an adduct compound of an alicyclic polyamine such as isophoronediamine or 1,3-bis (aminomethyl) cyclohexane, or a mixture of the adduct compound of the aliphatic polyamine and the adduct compound of the alicyclic polyamine as a main component. Those are preferred. In particular, a curing agent mainly composed of an adduct compound of xylylenediamine or isophoronediamine is preferable.

  As the above-mentioned aliphatic polyamine adduct compound, an aliphatic polyamine obtained by addition reaction of aryl glycidyl ether (particularly phenyl glycidyl ether or tolyl glycidyl ether) or alkyl glycidyl ether is preferable. The alicyclic polyamine adduct compound is preferably a compound obtained by subjecting the alicyclic polyamine to an addition reaction of n-butyl glycidyl ether, bisphenol A diglycidyl ether, or the like.

  Aliphatic polyamines include alkylenediamines having 2 to 6 carbon atoms such as ethylenediamine and propylenediamine, polyalkylene polyamines having 2 to 6 carbon atoms such as diethylenetriamine and triethylenetriamine, and aromatics having 8 to 15 carbon atoms such as xylylenediamine. Examples thereof include ring-containing aliphatic polyamines. Examples of commercially available aliphatic polyamines include FXE-1000 or FXR-1020, Fujicure FXR-1030, Fujicure FXR-1080, FXR-1090M2 (Fuji Kasei Kogyo Co., Ltd.), Ancamine (registered trademark) 2089K, Sanmide ( (Registered trademark) P-117, Sanmide X-4150, Ancamine 2422, Thurwet R, Sunmide TX-3000, Sunmide A-100 (manufactured by Air Products Japan), and the like.

  Examples of alicyclic polyamines include isophorone diamine, 1,3-bis (aminomethyl) cyclohexane, bis (4-aminocyclohexyl) methane, norbornene diamine, 1,2-diaminocyclohexane, and laromine. Examples of commercially available alicyclic polyamines include Ancamine 1618, Ancamine 2074, Ancamine 2596, Ancamine 2199, Sanmide IM-544, Sanmide I-544, Ancamine 2075, Ancamine 2280, Ancamine 1934, Ancamine 2228 (produced by Air Products Japan). ), Daitokural (registered trademark) F-5197, Daitokural B-1616 (manufactured by Daito Sangyo Co., Ltd.), Fuji Cure FXD-821, Fuji Cure 4233 (manufactured by Fuji Kasei Kogyo Co., Ltd.), jER Cure (registered trademark) 113 (Mitsubishi Chemical Corporation) Product), Lalomin (registered trademark) C-260 (manufactured by BASF) and the like.

  The blending ratio of the epoxy resin curing agent as described above is suitably 0.1 parts by mass or more and 30 parts by mass or less, preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the epoxy resin. When the blending ratio of the epoxy resin curing agent is less than 0.1 parts by mass with respect to 100 parts by mass of the epoxy resin, the curing rate of the epoxy resin composition is generally slowed down, and voids remain and cracks occur in the cured product Since it becomes easy, it is not preferable. On the other hand, if the blending ratio exceeds 30 parts by mass, it becomes difficult to obtain storage stability at room temperature.

In the case where the curable resin composition is a photocurable thermosetting resin composition, the photosensitive resin having an ethylenically unsaturated double bond in the molecule or a photosensitive compound (photopolymerizable monomer) is photocured. It is necessary to use together in the required amount.
As specific examples of the photosensitive resin, the following compounds (any of oligomers and polymers) are preferable.

  (1) A carboxyl group-containing resin obtained by copolymerization of an unsaturated carboxylic acid such as (meth) acrylic acid and an unsaturated group-containing compound such as styrene, α-methylstyrene, lower alkyl (meth) acrylate, and isobutylene. A carboxyl group-containing photosensitive resin obtained by reacting a compound having one or more ethylenically unsaturated groups and one epoxy group in a molecule.

  (2) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin obtained by a polyaddition reaction of (meth) acrylate or a partially acid anhydride-modified product thereof, a carboxyl group-containing dialcohol compound, and a diol compound.

  (3) During the synthesis of the resin of (2), a compound having one hydroxyl group and one or more (meth) acrylic groups in a molecule such as hydroxyalkyl (meth) acrylate is added, and terminal (meth) acrylated Carboxyl group-containing photosensitive urethane resin.

  (4) During the synthesis of the resin of (2), a compound having one isocyanate group and one or more (meth) acryl groups in the molecule, such as an equimolar reaction product of isophorone diisocyanate and pentaerythritol triacrylate, was added. Terminal (meth) acrylated carboxyl group-containing photosensitive urethane resin.

  (5) A dibasic acid anhydride such as phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc. is reacted with a hydroxyl group present in the side chain by reacting a bifunctional or higher polyfunctional epoxy resin with (meth) acrylic acid. A carboxyl group-containing photosensitive resin to which is added.

  (6) Carboxyl group-containing photosensitivity in which (meth) acrylic acid is reacted with a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional epoxy resin with epichlorohydrin, and a dibasic acid anhydride is added to the resulting hydroxyl group. Resin.

  (7) A cyclic ether such as ethylene oxide or a cyclic carbonate such as propylene carbonate is added to a polyfunctional phenolic compound such as novolak, and the resulting hydroxyl group is partially esterified with (meth) acrylic acid, and the remaining hydroxyl group is treated with maleic anhydride. Carboxyl group-containing photosensitive resin obtained by reacting polybasic acid anhydrides such as tetrahydrophthalic anhydride, trimellitic anhydride and pyromellitic anhydride.

(8) The resin of the above (1) to (7) further has one epoxy group and one or more (meth) acryloyl groups in the molecule such as glycidyl (meth) acrylate and α-methylglycidyl (meth) acrylate. A carboxyl group-containing photosensitive resin obtained by adding a compound.
In the present specification, (meth) acrylate is a term that collectively refers to acrylate, methacrylate, and mixtures thereof, and the same applies to other similar expressions.

  As a photosensitive compound used for the photocurable thermosetting resin composition of this invention, conventionally well-known polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, epoxy ( (Meth) acrylates can be used. Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, methoxytetraethylene glycol, polyethylene glycol and propylene glycol Acrylamides such as N, N-dimethylacrylamide, N-methylolacrylamide, N, N-dimethylaminopropylacrylamide; N, N-dimethylaminoethyl acetate , Aminoalkyl acrylates such as N, N-dimethylaminopropyl acrylate; polyhydric alcohols such as hexanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, tris-hydroxyethyl isocyanurate, or their ethylene oxide adducts; Polyvalent acrylates such as propylene oxide adduct or ε-caprolactone adduct; phenoxy acrylate, bisphenol A diacrylate, and polyvalent acrylates such as ethylene oxide adduct or propylene oxide adduct of these phenols; Glycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, triglycidyl isocyanurate Polyglycerides of any glycidyl ether; not limited to the above, acrylates and melamine acrylates obtained by directly acrylated polyols such as polyether polyol, polycarbonate diol, hydroxyl-terminated polybutadiene, polyester polyol, or urethane acrylate via diisocyanate And / or methacrylates corresponding to the acrylate.

  Further, an epoxy acrylate resin obtained by reacting acrylic acid with a polyfunctional epoxy resin such as a cresol novolac type epoxy resin, or a hydroxy acrylate such as pentaerythritol triacrylate and a diisocyanate such as isophorone diisocyanate on the hydroxyl group of the epoxy acrylate resin. Examples thereof include an epoxy urethane acrylate compound obtained by reacting a half urethane compound. Such an epoxy acrylate resin can improve photocurability without deteriorating the touch drying property.

  The compounding quantity of the photosensitive component which has several ethylenically unsaturated groups in such a molecule | numerator is 5 to 70 mass% in solid content of a composition, More preferably, it is 10 to 60 mass% The following are appropriate. When the blending amount is less than 5% by mass, the photocurability is lowered. On the other hand, when it exceeds 70% by mass, the coating becomes fragile, which is not preferable.

  As the photo radical polymerization initiator used in the present invention, an oxime ester photopolymerization initiator having an oxime ester group, an α-aminoacetophenone photopolymerization initiator, an acylphosphine oxide photopolymerization initiator, a benzoin compound, an acetophenone compound, A conventionally well-known radical photopolymerization initiator, such as an anthraquinone compound, a thioxanthone compound, a ketal compound, a benzophenone compound, a tertiary amine compound, and a xanthone compound, can be mentioned, and these can be used alone or in combination of two or more. Further, the radical photopolymerization initiator as described above may be N, N-dimethylaminobenzoic acid ethyl ester, N, N-dimethylaminobenzoic acid isoamyl ester, pentyl-4-dimethylaminobenzoate, triethylamine, triethanolamine, etc. It can be used in combination with one or more photosensitizers such as tertiary amines. In addition, when a deeper photocuring depth is required, a titanocene photopolymerization initiator such as CGI784 manufactured by Ciba Specialty Chemicals, which initiates radical polymerization in the visible region, and a leuco dye can be used as needed. It can be used in combination as an agent.

  The blending amount of the radical photopolymerization initiator and the photosensitizer is preferably 0.02% by mass or more and 10% by mass or less of the total amount of the composition. If it is less than 0.02% by mass, the photocurability on copper is insufficient. On the other hand, if it exceeds 10% by mass, the light absorption on the surface of the film becomes intense and the deep curability tends to be lowered.

  In the curable resin composition used in the present invention, the inorganic filler is used for stress relaxation due to curing shrinkage and adjustment of the linear expansion coefficient. As such an inorganic filler, the well-known inorganic filler used for a normal resin composition can be used. Specifically, for example, silica, barium sulfate, calcium carbonate, Neuburg silica, silicon nitride, aluminum nitride, boron nitride, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, titanium oxide, mica, talc, organic bentonite Nonmetallic fillers such as copper, metallic fillers such as copper, gold, silver, palladium, and silicone. These can be used alone or in combination of two or more.

  Among these inorganic fillers, silica and calcium carbonate excellent in low hygroscopicity and low volume expansibility are preferably used. Silica may be either amorphous or crystalline, or a mixture thereof. In particular, amorphous (fused) silica is preferred. The calcium carbonate may be either natural heavy calcium carbonate or synthetic precipitated calcium carbonate.

  Examples of the shape of such an inorganic filler include a spherical shape, a needle shape, a plate shape, a scale shape, a hollow shape, an indefinite shape, a hexagonal shape, a cubic shape, and a flake shape. preferable.

  The average particle size of these inorganic fillers is in the range of 0.1 μm or more and 25 μm or less, preferably 0.1 μm or more and 15 μm or less. When the average particle diameter is less than 0.1 μm, the specific surface area is large, and dispersion failure is likely to occur due to the influence of the aggregating action between the fillers, and it is difficult to increase the filling amount of the filler. On the other hand, when the thickness exceeds 25 μm, there is a problem that the filling property to the hole of the printed wiring board is deteriorated and the smoothness is deteriorated when the conductor layer is formed in the filled portion. More preferably, they are 1 micrometer or more and 10 micrometers or less.

  The blending ratio of such an inorganic filler is suitably 40% by mass or more and 90% by mass or less, preferably 40% by mass or more and 80% by mass or less, based on the total amount of the curable resin composition. If it is less than 40% by mass, the resulting cured product will have too much thermal expansion, and it will be difficult to obtain sufficient abrasiveness and adhesion. On the other hand, when it exceeds 90% by mass, it becomes difficult to form a paste, and it becomes difficult to obtain good printability and hole filling. More preferably, it is 50 mass% or more and 75 mass% or less.

  In the curable resin composition of the present invention, a filler treated with a fatty acid for imparting thixotropy, or an amorphous filler such as organic bentonite and talc can be added.

The fatty acid is represented by the general formula: (R ¹ COO) n-R ² (substituent R ¹ is a hydrocarbon having 5 or more carbon atoms, substituent R ² is hydrogen, metal alkoxide, or metal, and n is 1 or more. 4 or less) can be used. The fatty acid can exhibit an effect of imparting thixotropy when the substituent R ¹ has 5 or more carbon atoms. More preferably, n is 7 or more.

As a fatty acid, the unsaturated fatty acid which has a double bond or a triple bond in a carbon chain may be sufficient, and the saturated fatty acid which does not contain them may be sufficient. For example, stearic acid (the number of carbon atoms and the number of unsaturated bonds and the value in parentheses is a numerical expression depending on the position. 18: 0), hexanoic acid (6: 0), oleic acid (18: 1 (9)), icosane Examples include acid (20: 0), docosanoic acid (22: 0), and melicic acid (30: 0). These fatty acid substituents R ¹ preferably have 5 or more and 30 or less carbon atoms. More preferably, it has 5 or more and 20 or less carbon atoms. In addition, for example, metal alkoxides in which the substituent R ² is a titanate-based substituent capped with an alkoxyl group, etc., having a skeleton having a long (5 or more carbon atoms) fatty chain with a coupling agent structure It may be. For example, trade name KR-TTS (manufactured by Ajinomoto Fine Techno Co., Ltd.) can be used. In addition, metal soaps such as aluminum stearate and barium stearate (each manufactured by Kawamura Kasei Kogyo Co., Ltd.) can be used. Examples of other metal soap elements include Ca, Zn, Li, Mg, and Na.

  The proportion of such fatty acid is suitably 0.1 to 2 parts by mass with respect to 100 parts by mass of the inorganic filler. If it is less than 0.1 parts by mass, sufficient thixotropy cannot be imparted. On the other hand, if it exceeds 2 parts by mass, the apparent viscosity of the thermosetting resin composition becomes too high, resulting in holes in the printed wiring board. The embeddability in the part is reduced. In addition, after filling and curing in the hole portion, bubbles remain in the hole portion, so that the defoaming property is deteriorated, and voids and cracks are likely to occur. More preferably, they are 0.1 mass part or more and 1 mass part or less.

  A fatty acid may be mix | blended by using the inorganic filler surface-treated with the fatty acid previously, and it becomes possible to provide thixotropy to a thermosetting resin composition more effectively. In this case, the blending ratio of the fatty acid can be reduced as compared with the case where the untreated filler is used. When all the inorganic fillers are used as the fatty acid-treated filler, the blending ratio of the fatty acid is 0. It is preferable to be 1 part by mass or more and 1 part by mass or less.

  In the curable resin composition of the present invention, a silane coupling agent can be further used. By mix | blending a silane coupling agent, it becomes possible to improve the adhesiveness of an inorganic filler and an epoxy resin, and to suppress generation | occurrence | production of the crack in the hardened | cured material.

  Examples of the silane coupling agent include epoxy silane, vinyl silane, imidazole silane, mercapto silane, methacryloxy silane, amino silane, styryl silane, isocyanate silane, sulfide silane, ureido silane, and the like. Moreover, a silane coupling agent may be mix | blended by using the inorganic filler surface-treated with the silane coupling agent previously.

  The mixing ratio of such a silane coupling agent is preferably 0.05 parts by mass or more and 2.5 parts by mass or less with respect to 100 parts by mass of the inorganic filler. If it is less than 0.05 parts by mass, sufficient adhesion cannot be obtained, and cracks are likely to occur. On the other hand, when the amount exceeds 2.5 parts by mass, after filling and curing the thermosetting resin composition in the hole of the printed wiring board, bubbles remain in the hole and the defoaming property deteriorates, resulting in voids and cracks. Is likely to occur.

  The curable resin composition of the present invention does not necessarily use a diluting solvent when a liquid epoxy resin or a photosensitive compound is used at room temperature, but a small amount of diluting solvent is used to adjust the viscosity of the composition. It may be added. Examples of the diluent solvent include ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene and tetramethylbenzene; methyl cellosolve, butyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, propylene glycol monomethyl ether , Glycol ethers such as dipropylene glycol monoethyl ether and triethylene glycol monoethyl ether; esters such as ethyl acetate, butyl acetate, and acetates of the above glycol ethers; ethanol, propanol, ethylene glycol, propylene glycol, etc. Alcohols; aliphatic hydrocarbons such as octane and decane; petroleum oils such as petroleum ether, petroleum naphtha, hydrogenated petroleum naphtha, and solvent naphtha Organic solvents such as solvents. These can be used alone or in combination of two or more.

  The blending ratio of the dilution solvent is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less of the total amount of the curable resin composition. If the blending ratio of the dilution solvent exceeds 10% by mass, bubbles and cracks are likely to occur in the hole insulating layer after curing due to the effect of evaporation of volatile components during curing. Therefore, a solvent-less curable resin composition is particularly desirable.

  If necessary, the curable resin composition of the present invention may contain an oxazine compound having an oxazine ring obtained by reacting a phenol compound, formalin and a primary amine. By hardening the curable resin composition filled in the hole of the printed wiring board by containing the oxazine compound, when performing electroless plating on the formed cured product, curing with aqueous potassium permanganate solution or the like The roughening of the object can be facilitated and the peel strength with the plating can be improved.

  Further, known colorants such as phthalocyanine blue, phthalocyanine green, disazo yellow, titanium oxide, carbon black, and naphthalene black, which are used in ordinary resist inks for screen printing, may be added.

  In order to impart storage stability during storage, known thermal polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, pyrogallol, and phenothiazine, and clay, kaolin, Known thickeners such as organic bentonite and montmorillonite, and thixotropic agents can be added. In addition, known additives such as antifoaming agents such as silicones, fluorines, and polymers, leveling agents, and adhesion-imparting agents such as imidazoles, thiazoles, triazoles, and silane coupling agents are blended. be able to.

  In the obtained curable resin composition, the viscosity measured by a rotary viscometer is preferably 100 dPa · Sec or more and 1000 dPa · Sec or less at a 30 Sec value of 25 ° C. and 5 rpm. If it is less than 100 dPa · Sec, shape retention becomes difficult and sagging occurs. On the other hand, when it exceeds 1000 dPa · Sec, the embedding property in the hole of the printed wiring board is lowered. More preferably, it is 200 dPa · Sec or more and 800 dPa · Sec or less.

  The viscosity is measured with a cone plate viscometer composed of a cone rotor (conical rotor) and a plate described in JIS Z 8803, for example, TV-30 type (manufactured by Toki Sangyo, rotor 3 ° × R9.7). The

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, it cannot be overemphasized that this invention is not limited to the following Example. In the following description, “parts” and “%” are based on mass unless otherwise specified.

<Preparation of thermosetting resin composition>
40 parts of bisphenol A type epoxy resin (Mitsubishi Chemical Co., Ltd. jER828), 30 parts of bisphenol F type epoxy resin (Mitsubishi Chemical Co., Ltd. jER807), aminophenol type epoxy resin (Sumitomo Chemical Co., Ltd. ELM-100H) 30 parts, 6 parts of epoxy resin curing agent (2MZ-AP manufactured by Shikoku Kasei Kogyo Co., Ltd.), and 120 parts of inorganic filler (Super # 2000 manufactured by Maruo Calcium Co., Ltd.) were premixed with a stirrer and then 3 Dispersion was performed with a roll mill to prepare pastes of thermosetting resin compositions used in Examples 1 to 4 and Comparative Examples 2 and 3 below.

<Preparation of light / thermosetting resin composition>
100 parts of 40% methacrylic acid adduct of dicyclopentadiene phenol type epoxy resin, 30 parts of dicyclopentanyl methacrylate, 70 parts of trimethylolpropane triacrylate, 80 parts of dipentaerythritol hexaacrylate, 2-methyl-1 [4- ( Methylthio) phenyl] -2-morpholinopropan-1-one 10 parts, diethylthioxanthone 1 part, bisphenol A type epoxy resin 80 parts, bisphenol AD type epoxy resin 20 parts, dicyandiamide 10 parts, silica 250 parts, surface-treated colloidal silica 6 parts and 3 parts of polydimethylsiloxane were stirred and mixed, and then uniformly dispersed by a three-roll mill. The obtained uniform dispersion was vacuum degassed to prepare a paste of the light / thermosetting resin composition used in Comparative Example 1.

<Preparation Example 1 of Substrate>
A double-sided printed wiring board (through-hole) as shown in FIG. 1A, in which a conductor pattern 2 is formed on both sides of an insulating board (thickness 0.930 mm) and the inner wall of a through hole 3 having the same diameter is plated with copper. A hole diameter of 0.25 mm, a copper circuit thickness of 40 μm, a line / space (L / S) = 20 μm / 40 μm, and a through hole diameter of 100 μm after plating were used. The surface of the conductive layer that had been roughened in advance with “MEC etch bond CZ-8101” (manufactured by MEC, chemical roughening chemical) was used.

Example 1
The plated through hole of the double-sided printed wiring board is filled with the thermosetting resin composition 4 by a single screen printing with a dot pattern (as shown in FIG. 1 (B)), and protrudes from the hole surface. The portion of the thermosetting resin composition that had been removed was scraped with a squeegee to flatten the surface of the substrate (the state shown in FIG. 1C). Next, the thermosetting resin composition filled in the holes was cured by heating at 150 ° C. for 30 minutes. Next, the prepreg or the resin-coated copper foil 5 was laminated on both surfaces of the substrate 1 and pressed and integrated under the conditions of 25 kgf / cm ² , 170 ° C. and 30 minutes to produce an evaluation substrate (shown in FIG. 1D). State).

Example 2
In Example 1, the flattening of the substrate surface is removed by sandwiching the substrate between the support film and the roll laminator, and transferring the portion protruding from the hole surface of the filled curable resin composition to the support film. Except for the above, in the same manner as in Example 1, it was molded into the state shown in FIG.

Example 3
In Example 1, the thermosetting resin composition 4 was filled into the through hole by roll printing with a dot pattern, and molded into the state shown in FIG. A substrate was manufactured.

Example 4
In Example 1, the thermosetting resin composition 4 is filled into the through holes by molding in the same manner as in Example 1 except that the entire surface is applied by roll printing, as shown in FIG. An evaluation board was manufactured.

Comparative Example 1
The photo / thermosetting resin composition was applied onto one surface (preceding surface) of the substrate 11 by roll printing to fill the through holes and the recesses between the circuits (the state shown in FIG. 3B). Next, the substrate was placed on a horizontal rack and heated at 80 ° C. for 30 minutes with a BOX dryer. Next, this substrate was sandwiched between 100 μm-thick PET films 19 as shown in FIG. That is, this film-coated substrate is sandwiched between two stainless steel rollers 20 as shown in FIG. 3 (D), under conditions of laminating pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature 100 ° C. Then, the roller 20 was moved on the film 19, and the coating resin layer on the surface of the substrate was made flat and thin. Next, the substrate was irradiated with light at an exposure amount of 1200 mJ / cm ² using a high-pressure mercury lamp to photocure the coated resin layer, and then the PET films 19 on both sides were peeled off and removed (FIG. 3). (The state shown in (E)). Next, the back surface (following surface) of the substrate 11 was processed in the same manner as the preceding surface. That is, the photo / thermosetting resin composition was applied to the entire back surface (rear surface) of the substrate 11 by roll printing and filled in the recesses between the circuits (the state shown in FIG. 3F). Next, the substrate was placed on a horizontal rack, heated with a BOX dryer at 80 ° C. for 30 minutes, and then sandwiched between PET films 19 having a film thickness of 100 μm. The film substrate is sandwiched between two stainless steel rollers 20 as shown in FIG. 3 (G), and the film is placed under the conditions of laminating pressure 0.1 MPa, laminating speed 0.5 m / min, laminating temperature 100 ° C. The coating resin layer on the surface of the substrate was flattened and thinned (the state shown in FIG. 3H). Next, the substrate was irradiated with light at an exposure amount of 1200 mJ / cm ² using a high-pressure mercury lamp to photocure the coated resin layer, and then the PET films 19 on both sides were peeled off and removed. Thereafter, this substrate was heated at 150 ° C. for 30 minutes to perform thermosetting, and an evaluation substrate was manufactured (state shown in FIG. 3I).

Comparative Example 2
The plated through hole 13 of the substrate 11 is filled with the thermosetting resin composition 14 by screen printing with a dot pattern (as shown in FIG. 4B), and heated to 150 ° C. in a heating furnace, Primary curing was performed at this temperature for 30 minutes. Next, as shown in FIG. 4C, a copper foil 15 with resin was laminated on both surfaces of the substrate to form a double-sided copper-clad laminate. In FIG. 4C, 16 is a copper foil of a resin-coated copper foil, and 17 is a resin layer of a resin-coated copper foil. Next, the double-sided copper-clad laminate was heated and vacuum pressed, and the resin layer of the resin-coated copper foil 15 was thermally cured simultaneously with the secondary thermosetting of the primary thermoset to produce a hole-filled double-sided copper-clad laminate. (State shown in FIG. 4C). Next, a dry film was laminated on both surfaces of the hole-filled double-sided copper-clad laminate, a negative film (pattern mask) was overlaid, and exposed and cured with an ultrahigh pressure mercury lamp. Next, the carrier film of the dry film was peeled off, and a developer (1% sodium carbonate solution) was sprayed and developed on the exposed resist surface from a spray nozzle, and then washed with water to form a resist pattern. Next, a ferric chloride solution (36% by weight) was sprayed from both sides of the resist-coated double-sided copper-clad laminate through a spray nozzle to dissolve and remove unnecessary copper foil. After completion of the etching, a 3% sodium hydroxide aqueous solution was sprayed from a spray nozzle and washed away while swelling the etching resist to produce an evaluation substrate (state shown in FIG. 4D).

Comparative Example 3
A release film 21 [polyester film having the same size as the substrate 11 (manufactured by Panac Co., Ltd., re-peeling film GS, thickness 50 μm)] was attached to the back surface of the substrate 11. As shown in FIG. 5 (A), this is fitted into a recess (the same depth as the total thickness of the substrate and the release film) of the substrate fixing base 23 in the vacuum chamber 22, and is fixed by exhausting and sucking from the exhaust port 24. did. Next, as shown in FIG. 5 (B), after the thermosetting resin composition 14 is placed on the end of the substrate 11, the inside of the vacuum chamber 22 is depressurized to 0.15 kPa, and the moving speed (ia) 30. 0 mm / sec, peripheral speed (va) 75.0 mm / sec, shortest distance 1.2 mm between the non-contact roll 25 and the substrate 11, 0.5 mm distance between the tip of the doctor 26 and the substrate 11, doctor surface and substrate surface Was filled so that the angle (right angle in the figure) was 15 °, and then the inside of the vacuum chamber 22 was returned to atmospheric pressure to obtain a substrate having a resin layer. Subsequently (as is, without removing the substrate), as shown in FIG. 5C, the doctor 26 is reversed with the rotation axis X of the non-contact roll 25 as the central axis and arranged on the opposite side to the non-contact roll 25. In the vacuum chamber at atmospheric pressure, as shown in FIG. 5 (D), the moving speed (i) is 20 mm / second, the peripheral speed (v) is 50 mm / second, and the tip of the doctor 26 as shown in FIG. The contact pressure on the substrate surface is 800 N / m, and the angle between the doctor surface and the substrate surface (left side in the figure) is 45 °, scraping off excess resin on the substrate to produce a filled substrate. (State shown in FIG. 5E). The obtained filled substrate was heated and cured at 130 ° C. for 30 minutes in a circulating air oven, and then the release film 21 was removed to obtain a cured substrate. Next, after polishing using a uniaxial non-woven cloth buffing device (trade name “IDB-600” manufactured by Ishii Notation Co., Ltd., roughness No. 600 buff 2 times) to flatten the surface, in a circulating heating oven An evaluation substrate was manufactured by heating and curing at 150 ° C. for 30 minutes.

<Performance evaluation>
Performance evaluation as listed below was performed for each evaluation substrate obtained as described above. The results are summarized in Table 1.

Bubble generation:
After polishing the evaluation substrate for cross-sectional observation, it was observed with an optical microscope to confirm whether bubbles were generated in the cured product in the through-hole portion. The judgment criteria are as follows.
○: No generation of bubbles.
×: Bubbles are generated.

Occurrence of delamination (after pressing):
Whether or not delamination (a phenomenon in which the periphery of the through hole is lifted during solder leveling, hereinafter abbreviated as “delamination”) occurs at the interface between the hole filling portion of the evaluation board and the prepreg or copper foil with resin. Observed and evaluated according to the following criteria.
○: No delamination occurred.
X: A delamination state was observed around the hole insulating layer.

Generation of delamination (after solder heat resistance):
The evaluation board was immersed in a solder liquid at 288 ° C. for 5 seconds for 10 seconds, and then allowed to cool to room temperature. After being polished for cross-sectional observation, it was observed with an optical microscope, and the presence or absence of delamination between the hole-filling resin and the prepreg or the copper foil with resin was evaluated.
○: No delamination occurred.
X: A delamination state was observed around the hole insulating layer.

Substrate flatness:
The determination was made based on whether a difference of 5 μm or more occurred in the thicknesses of the front and back insulating layers of the evaluation substrate.
A: The thickness difference between the front and back insulating layers is less than 5 μm.
X: The thickness difference between the front and back insulating layers is 5 μm or more.

Laser processability:
After forming vias on the evaluation substrate using a carbon dioxide laser, the opening shape of the cross section was observed with a microscope, and laser workability was evaluated according to the following criteria.
○: The shape of the formed via is constant, and the bottom of the via reaches the conductor pattern surface.
X: The shape of the formed via is not uniform, or the bottom of the via does not reach the conductor pattern surface.

Smear residue:
After forming vias on the evaluation substrate using a carbon dioxide laser, desmear treatment was performed using a chemical solution manufactured by Rohm & Haas Co., Ltd. Specifically, after being immersed in MLB-211 at 80 ° C. for 10 minutes (swelling treatment), immersed in MLB-213 at 80 ° C. for 20 minutes (roughening treatment), and then in MLB-216-2 at 50 ° C. for 5 minutes. Soaked.
After the desmear treatment, the bottom and wall surface of the via were observed with a scanning electron microscope (SEM) to confirm the presence or absence of smear residues.
○: No residue.
X: Residue present.

As shown in Table 1, in the case of Examples 1 to 4, there was no generation of bubbles or delamination, and the flatness of the substrate, laser processability, and desmear resistance were excellent.
On the other hand, in the case of Comparative Examples 1 and 2, there was a problem with the flatness of the substrate. If an adjustment is made according to the filling amount, it is easily influenced by various factors, and the adjustment is difficult. For example, when the filling amount is large, it is difficult to completely flatten the filling portion even if pressure is applied, and a difference occurs in the thickness of the substrate between the filling portion and other portions. Further, in order to solve the above problem, when the filling amount is decreased, the prepreg flows into the plated through hole, and the thickness of the prepreg changes between the front and back sides. In order to flatten the substrate thickness, it is necessary to accurately adjust the filling amount, but the filling amount is greatly affected by the viscosity and TI value of the hole filling resin, the through-hole diameter, the thickness of the substrate, and the like. It is difficult to adjust the filling amount.

  In Comparative Examples 1 and 2, problems also occurred with respect to laser processability and smear residues. This is because with the increase in circuit density, vias are often formed immediately above or immediately adjacent to the through holes. In this case, in Comparative Examples 1 and 2, the via-filling resin component is formed in the portions where vias are formed. (Filling part) and other resin components (such as prepreg) come to coexist. Since the composition of the hole filling resin component and the prepreg is different, it is considered that the formation state is affected when the via formation conditions (laser processing conditions) are the same. As a result, there is a high possibility that vias in different states are formed.

  On the other hand, in Comparative Example 3, bubbles and delamination occurred, or the heat resistance was poor. This is because the printing and filling mechanism of Comparative Example 3 is a coating operation in a vacuum, and an adhesive PET film is stretched on the back surface of the substrate to make a pseudo bottomed via state. This is a method of filling, and since the lower end portion of the through hole is closed by the PET film, it is considered that there is no escape space for bubbles and bubbles are generated. In addition, as for the surface state after coating and curing, the printed surface and the film surface are dented due to the curing shrinkage of the resin (the film peeling is performed after the resin paste is cured), and this dent was laminated and pressed with a prepreg or the like. It is thought that it sometimes caused delamination. In addition, the occurrence of this delamination is thought to have led to poor solder heat resistance. Furthermore, since it is not in a completely vacuum state when filling the hole filling resin, it is considered that a portion having poor fillability is generated at the bottom surface, which causes bubbles to be generated.

<Example 2 of substrate preparation>
FIG. 1 was produced in the same manner as in Preparation Example 1 of the substrate except that the conductor pattern 2 was formed on both surfaces of the insulating substrate (thickness 0.8 mm), and a plurality of through holes 3 having different diameters were formed. Double-sided printed wiring board as shown in (A) (through hole diameter 1 is 0.25 mm, through hole diameter 2 is 0.15 mm, copper circuit thickness is 40 μm, line / space (L / S) = 20 μm / 40 μm) It was used.

Example 5
In Example 1, an evaluation board was produced in the same manner as in Example 1 except that the double-sided printed wiring board produced in Preparation Example 2 of the board was used.

Example 6
In Example 2, an evaluation board was produced in the same manner as in Example 2 except that the double-sided printed wiring board produced in Preparation Example 2 of the board was used.

Example 7
In Example 4, an evaluation board was produced in the same manner as in Example 4 except that the double-sided printed wiring board produced in Preparation Example 2 of the board was used.

Comparative Example 4
In Example 5, the surface of the substrate was buffed after heat curing instead of scraping the portion of the thermosetting resin composition protruding from the surface of the hole with a squeegee before curing and flattening the surface of the substrate. An evaluation substrate was produced in the same manner as in Example 5 except that the surface was flattened.

Comparative Example 5
In Comparative Example 1, an evaluation board was produced in the same manner as in Comparative Example 1, except that the double-sided printed wiring board produced in Preparation Example 2 of the board was used.

Comparative Example 6
In Comparative Example 2, an evaluation board was produced in the same manner as in Comparative Example 2 except that the double-sided printed wiring board produced in Preparation Example 2 of the board was used.

<Performance evaluation>
For each evaluation substrate obtained as described above, performance evaluation was performed in the same manner as described above. The results are summarized in Table 2.

As shown in Table 2, in the case of Examples 5 to 7, even in the case of a substrate having a plurality of through holes having different diameters, the curable resin does not generate an unfilled portion by one printing. The composition could be filled, and there was no generation of bubbles or delamination, and the substrate flatness, laser processability, and desmear resistance were excellent.
On the other hand, in the case of the polishing method after curing (Comparative Example 4), if the through holes having different diameters are filled by one printing, a difference occurs in the protruding amount from the hole (printing conditions). If you match with a large-diameter through-hole, an unfilled part will occur in the small-diameter through-hole, and if you adjust the printing conditions to the small-diameter through-hole, the amount of protrusion from the large-diameter through-hole will be larger than the small-diameter through-hole. Therefore, bubbles and delamination occurred. In addition, since the amount of protrusion varies depending on the diameter of the through hole as described above, a polishing residue is generated, and accordingly, a problem occurs with laser processability and smear residue, or excessive polishing causes the substrate surface to be polished. Scratching and substrate dimensional changes and distortions occurred. In addition, in order to eliminate such problems in the flattening of the substrate, when printing is performed a plurality of times, a dot pattern suitable for the size of each diameter is used and printing conditions suitable for the size of the diameter are used. It is necessary to perform filling, that is, the number of times of printing corresponding to the number of diameters. In this case, the amount of protrusion from the hole is substantially constant regardless of the size of the diameter. Therefore, the above problems do not occur in polishing after curing, and the quality of the substrate can be maintained. However, the printing process takes time, and the time and processing cost for creating the substrate increase.

On the other hand, in the method of flattening the protruding portion by the pressurization method (Comparative Examples 5 and 6), as in Comparative Example 4, when filling through holes with different diameters by one printing, There is a difference in the amount of protrusion (when the printing conditions are matched to a small-diameter through hole, the protrusion amount of the large-diameter through hole becomes larger than the small diameter). When flattening is attempted with a pressure type in a state where the protruding amount is different, the flattening is not completely flat. The thickness of the substrate with a large amount of protrusion increases, and the thickness of the portion with a small amount of protrusion decreases. As a result, there were problems with laser processability and smear residues. When the printing conditions are matched with a large-diameter through hole, an unfilled portion is generated in the small-diameter through hole. In this case, bubbles and delamination are generated.
In the case of Comparative Example 6, printing can be performed a plurality of times. In that case, the dot pattern suitable for the size of each diameter is used, and filling is performed under the printing conditions suitable for the size of the diameter. That is, the number of times of printing corresponding to the number of diameters is required. The amount of protrusion from the hole in this case is substantially constant regardless of the size of the diameter, but it takes time for the printing process and increases the time and processing cost for creating the substrate. On the other hand, in the case of the comparative example 5, since it is solid printing, it is impossible to print in multiple times.

DESCRIPTION OF SYMBOLS 1,11 Board | substrate 2,12,8,18 Conductor pattern 3,13 Through hole 4,14 Curable resin composition 5,15 Copper foil with resin 6,16 Copper foil 7,17 Curable resin composition 19 PET film 20 Roller 21 Release film 22 Vacuum chamber 23 Substrate fixing base 24 Exhaust port 25 Non-contact roll 26 Doctor

Claims (6)

  The curable resin composition is filled into the double-sided board of the printed wiring board or the through hole of the multilayer substrate, and before the curable resin composition is cured, the surface of the curable resin composition is planarized by a method other than polishing. The manufacturing method of the multilayer printed wiring board characterized by including a process.   The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the through holes are a plurality of through holes having the same diameter and / or a plurality of different diameters.   3. The multilayer printed wiring board according to claim 1, wherein the flattening step is performed by scraping a portion where the curable resin composition protrudes from the surface of the through hole using a doctor. 4. Manufacturing method.   The said curable resin composition is a thermosetting resin composition or a photocurable thermosetting resin composition, The multilayer printed wiring board as described in any one of Claims 1-3 characterized by the above-mentioned. Production method.   A multilayer printed wiring board manufactured by the manufacturing method according to claim 1.   It uses for the manufacturing method of the multilayer printed wiring board as described in any one of Claims 1-3 whose said curable resin composition is a thermosetting resin composition or a photocurable thermosetting resin composition. A curable resin composition characterized by being made.

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