JP2000228582A - Manufacture of printed wiring board having highly reliable through hole - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability of the copper foil in a small-diameter through hole and the surface-layer copper foil after the through hole is made by directly projecting a high-output carbon dioxide gas laser beam upon a copper-clad board. SOLUTION: A through hole is formed by removing the copper foil of a copper-clad board having two or more copper layers by performing metal oxidizing on the copper foil or forming a resin layer containing 3-97 vol.% metal compound power, carbon power, or metal power or a resin layer applied to a film and having a total thickness of 20-200 μm on the copper foil and projecting a high-output carbon dioxide gas laser beam selected from 20-60 mJ/pulse upon the resin layer. After the through hole is formed, the front and rear surfaces of the copper foil and produced burrs are etched off and the inside of the through hole is wetted after a vapor-phase treatment. Then a printed wiring board is manufactured by using the copper-clad board the hole of which is 80% filled with plated copper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for piercing through holes for through holes by directly irradiating a high power carbon dioxide gas laser to a copper surface of a copper multilayer board having at least two copper layers. The present invention relates to a method for manufacturing a printed wiring board using a copper-clad board formed by plating most of the inside of a hole with copper. In a more preferable aspect of the present invention, after removing the resin layer adhered and remaining on the surface of the copper foil inside the through-hole, preferably, the copper foil on the front and back surfaces is planarly removed by etching and also the burrs around the hole are removed. The present invention relates to a method for manufacturing a printed wiring board using a copper-clad board formed by plating most of the inside of a hole with copper.
The obtained double-sided, multilayer printed wiring board is suitable for use as a new semiconductor plastic package or the like as a high-density small printed wiring board having small-diameter holes.

[0002]

2. Description of the Related Art Hitherto, in high-density printed wiring boards used for semiconductor plastic packages and the like, through holes for through holes have been drilled. In recent years, the diameter of drills has become smaller and smaller, and the hole diameter has been reduced to 0.15 mmφ or less.When drilling such small holes, the drill diameter is small, so the drill bends, breaks, and the processing speed when drilling. It has disadvantages such as slowness, and has problems in productivity, reliability, and the like. Also, if holes of the same size are made in advance by using a negative film on the upper and lower copper foils by a predetermined method, and a through-hole that penetrates the upper and lower sides with a carbon dioxide gas laser is to be formed, the position of the inner layer copper foil shifts. In addition, there are disadvantages such as misalignment of upper and lower holes, poor connection, and inability to form front and back lands. Further, when a copper foil was used as the inner layer, even if the surface layer copper foil was removed by etching to form a hole with low energy, the inner layer copper foil could not be formed and a through hole could not be formed.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above problems by forming a small-diameter through-hole in a double-sided copper-clad board or a double-sided copper-clad multilayer board to form an inner layer copper foil and a front and back copper foil. The present invention relates to a method for manufacturing a printed wiring board having improved bondability between a metal and plated copper.

[0004]

SUMMARY OF THE INVENTION The present invention provides at least two
On the copper foil surface of a copper multilayer board having more than one copper layer, as a processing aid for the copper foil surface, a melting point of 90 in the resin composition.
A paint containing 3 to 97% by volume of one or more metal compound powders, carbon powders or metal powders having a binding energy of 300 kJ / mol or more at 0 ° C. or more, or a sheet-like paint thereof Preferably, it is arranged on the copper foil surface with a total thickness of 30 to 200 μm, or a metal oxide treatment of the copper foil surface is performed, and then 20 to 60 mJ / sufficient to remove the copper foil with a carbon dioxide gas laser. Using the energy selected from the pulse, the carbon dioxide laser is irradiated by the pulse oscillation of the carbon dioxide gas laser, the copper foil of the copper clad plate is processed to form a through hole, and then adheres to the copper foil surface inside the hole A copper-clad board obtained by filling 80% by volume or more of the hole volume with copper plating after removing the resin layer to be used for a printed wiring board, and manufacturing a printed wiring board having excellent through-hole reliability. Provide a way. Lay several copper-clad boards under the auxiliary material for processing,
It is also possible to perform through-hole processing with a carbon dioxide laser from above. After processing, the surface of the copper foil can be deburred by mechanical polishing. However, to completely remove burr,
It is preferable that both surfaces of the copper foil be planarly etched, a part of the thickness of the original copper foil be removed by etching, and copper burrs protruding in the holes be removed by etching. Through the above etching method, a through-hole plating hole in which copper foil on both surfaces around the hole remains is formed. Further, the land can be formed without displacement of the copper foil positions of the upper and lower holes, and the through hole can be formed without bending up and down. Adopting chemical etching treatment, the copper foil becomes thinner, and in the circuit formation of the fine wire of the front and back copper foil obtained by plating up with the subsequent metal plating, there is no occurrence of defects such as short circuit and pattern breakage, high density Printed wiring boards can be manufactured. After the thinning of the copper by etching of the front and back copper foils, the resin layer adhering to the surface of the inner copper foil exposed inside the hole is preferably removed by at least gas phase treatment. Even in the case of a double-sided copper-clad board, when the surface copper foil burrs are not removed by etching, the resin layer adhering to the copper surface is removed by vapor phase treatment or the like. Thereafter, the inside of the hole is filled with copper plating at 80% by volume or more, and the copper foil on the surface layer and the copper foil inside the hole are connected, whereby a hole with extremely excellent connection can be obtained. In addition, the processing speed was remarkably higher than that of the case of drilling, and a product having good productivity and excellent economy was obtained.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method for forming a through hole for a through hole, particularly a small diameter hole, in a multilayer board having at least two copper layers by using a carbon dioxide laser. The perforated multilayer printed wiring board is mainly used for mounting a semiconductor chip. When drilling a multilayer board with a carbon dioxide laser, apply a metal oxide treatment to the surface to be irradiated with the laser, or dissolve in water with a metal oxide powder, carbon, or metal powder having a melting point of 900 ° C and a binding energy of 300 kJ / mol or more. A paint mixed with a resin is applied to form a coating, or on one side of a thermoplastic film, a total thickness of 30 to 20.
An auxiliary sheet for drilling obtained by adhering to 0 μm is arranged, preferably adhered to the copper foil surface, and a carbon dioxide laser is directly irradiated on the copper foil surface from above, and the copper foil is processed and removed. And a method of forming a through hole for a through hole.

[0006] The copper clad board used in the present invention has at least 2
A double-sided copper-clad, multilayer board with more than one layer of copper,
The insulating layer may be any of a substrate-reinforced substrate, a film substrate, and a resin alone having no reinforcing substrate.

[0007] The auxiliary sheet for laser drilling of the present invention comprises:
It can be used as it is. However, it is preferable to place it on a copper-clad plate at the time of drilling and make it as close as possible to the copper foil surface in order to improve the shape of the hole. Generally,
The sheet is fixed and adhered to the copper-clad board by a method such as attaching it with tape or the like. However, in order to adhere more completely, the obtained sheet is oriented on the surface of the copper-clad board with the resin attached, and the resin is melt-bonded under heat and pressure,
Alternatively, the surface of the resin is pre-moistened with water at 3 μm or less, and then adhered under pressure at room temperature, whereby the adhesion to the copper foil surface becomes good, and a good hole shape can be obtained. As the resin composition, a water-soluble resin is preferable, but a resin composition that is not water-soluble and can be dissolved in an organic solvent can also be used. However, the resin may adhere around the holes by carbon dioxide laser irradiation. In this case, it is necessary to remove the resin, and the removal of the resin requires an organic solvent instead of water, which is not preferable because it is complicated in processing and causes problems such as contamination in a later step.

As the base material used for the copper clad board in the present invention, generally known organic and inorganic woven fabrics and nonwoven fabrics can be used. Specifically, as inorganic fibers, E, S, D,
Fibers, such as M glass, are mentioned. Examples of the organic fibers include wholly aromatic polyamide and liquid crystal polyester fibers. These may be mixed.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used. Specifically, an epoxy resin, a polyfunctional cyanate ester resin, a polyfunctional maleimide-cyanate ester resin, a polyfunctional maleimide resin, an unsaturated group-containing polyphenylene ether resin, and the like, and one or more kinds Are used in combination. From the viewpoint of through-hole shape in processing by high-output carbon dioxide laser irradiation, a thermosetting resin composition having a glass transition temperature of 150 ° C or higher is preferable, and has moisture resistance, migration resistance, and electrical characteristics after moisture absorption. In view of the above, a polyfunctional cyanate resin composition is preferred.

The polyfunctional cyanate compound which is a preferred thermosetting resin component of the present invention is a compound having two or more cyanato groups in a molecule. Specific examples include 1,3- or 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-, 1,4-, 1,6-, 1,8-, 2 , 6- or 2,7-
Dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4-dicyanatobiphenyl, bis (4-dicyanatophenyl) methane, 2,2-bis (4-cyanatophenyl) propane, 2,2- Bis (3,5-dibromo-4-cyanatophenyl) propane, bis (4-cyanatophenyl) ether, bis (4-cyanatophenyl) thioether, bis (4-cyanatophenyl) sulfone, tris (4-cy (Anatophenyl) phosphite, tris (4-cyanatophenyl) phosphate, and cyanates obtained by reacting novolak with cyanogen halide.

In addition to these, Japanese Patent Publication Nos. 41-1928 and 43-1846
8, polyfunctional cyanate compounds described in JP-A-44-4791, JP-A-45-11712, JP-A-46-41112, JP-A-47-26853 and JP-A-51-63149 can also be used. Further, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerization of a cyanato group of these polyfunctional cyanate compounds is used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer with a catalyst such as an acid such as a mineral acid or a Lewis acid; a base such as a tertiary amine such as sodium alcoholate; or a salt such as sodium carbonate. It can be obtained by: The prepolymer also contains some unreacted monomers and is in the form of a mixture of the monomer and the prepolymer, and such a raw material is suitably used for the purpose of the present invention. Generally, it is used after being dissolved in a soluble organic solvent.

As the epoxy resin, a generally known epoxy resin can be used. Specifically, liquid or solid bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, alicyclic epoxy resin; butadiene, pentadiene, vinylcyclohexene, dicyclopentyl ether, etc. And polyglycidyl compounds obtained by reacting a polyol, a hydroxyl-containing silicone resin with an epohalohydrin, and the like. These may be used alone or in combination of two or more.

As the polyimide resin, generally known ones can be used. Specific examples include a reaction product of a polyfunctional maleimide and a polyamine, and a polyimide having a terminal triple bond described in JP-B-57-005406.

These thermosetting resins may be used alone, but it is preferable to use them in combination as appropriate in consideration of the balance of properties.

Various additives can be added to the thermosetting resin composition of the present invention, if desired, as long as the inherent properties of the composition are not impaired. These additives include polymerizable double bond-containing monomers such as unsaturated polyesters and prepolymers thereof; polybutadiene, epoxidized butadiene, maleated butadiene, butadiene-
Low molecular weight liquid to high molecular weight elastic rubbers such as acrylonitrile copolymer, polychloroprene, butadiene-styrene copolymer, polyisoprene, butyl rubber, fluororubber, natural rubber; polyethylene, polypropylene, polybutene, poly-4-methyl Penten, polystyrene, AS
Resin, ABS resin, MBS resin, styrene-isoprene rubber,
Polyethylene-propylene copolymer, 4-fluoroethylene-
6-fluorinated ethylene copolymers; high molecular weight prepolymers or oligomers such as polycarbonate, polyphenylene ether, polysulfone, polyester, and polyphenylene sulfide; and polyurethane are exemplified and used as appropriate. In addition, other known organic fillers, dyes,
Pigments, thickeners, lubricants, defoamers, dispersants, leveling agents,
Various additives such as a photosensitizer, a flame retardant, a brightener, a polymerization inhibitor, and a thixotropy-imparting agent are used in an appropriate combination as required. If necessary, the compound having a reactive group is appropriately blended with a curing agent and a catalyst.

The thermosetting resin composition of the present invention can be cured by heating itself, but has a low curing rate and is inferior in workability and economic efficiency. Can be used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, per 100 parts by weight of the thermosetting resin.

The auxiliary material used in the present invention has a melting point of 90.
As the metal compound having a binding energy of 300 kJ / mol or more at 0 ° C. or more, generally known metal compounds can be used. Specifically, as the oxide, titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, manganese dioxide, zinc oxide such as zinc oxide , Silicon oxide, aluminum oxide, rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, and tungsten oxides such as tungsten oxide. Examples of the non-oxide include generally known ones such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, and rare earth oxysulfide. In addition, carbon can also be used. Further, various glasses which are a mixture of the metal oxide powders may be mentioned. In addition, carbon powders may be mentioned, and further, simple substances such as silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc and the like. An alloy metal powder is used. These may be used alone or in combination of two or more. The average particle size is
Although not particularly limited, 1 μm or less is preferable.

Since the molecules are dissociated or melted and scattered by the irradiation of the carbon dioxide laser, the metal adheres to the hole wall or the like and does not adversely affect the semiconductor chip and the hole wall adhesion. preferable. Since Na, K, Cl ions and the like particularly adversely affect the reliability of the semiconductor, those containing these components are not suitable. The compounding amount is 3 to 97% by volume, preferably 5 to 95% by volume, and is preferably mixed with the water-soluble resin and uniformly dispersed.

The water-soluble resin as an auxiliary material is not particularly limited, but when kneaded, applied to the surface of a copper foil and dried,
Alternatively, in the case of a sheet shape, a material that does not lose peeling is selected. For example, generally known materials such as polyvinyl alcohol, polyester, polyether and starch are used.

The method of preparing the metal compound powder, carbon powder or the composition comprising the metal powder and the resin is not particularly limited, but is kneaded at a high temperature without solvent in a kneader or the like, and extruded into a sheet shape on a thermoplastic film. A method of forming a film by dissolving a water-soluble resin in water, adding the powder to the mixture, uniformly stirring and mixing the mixture, applying the mixture to a thermoplastic film as a paint, and drying. A generally known method can be used. The thickness is not particularly limited, but is generally used in a total thickness of 30 to 200 μm.

In addition, it is possible to similarly form a hole after performing a metal oxide treatment on the surface of the copper foil, but it is more preferable to use the above-mentioned auxiliary material in view of the hole shape and the like. When laminating under heat and pressure on the copper foil surface, the coated resin layer is directed to the copper foil surface, and the temperature is generally 40 to 150 ° C., preferably 60 to 120 ° C., and the linear pressure is preferably 1 to 40 ° C. Lamination is performed under a pressure of 〜１０10 kg, and the resin layer is melted and brought into close contact with the copper foil surface. The selection of the temperature depends on the melting point of the water-soluble resin to be used, and also depends on the linear pressure and the laminating speed. In general, lamination is performed at a temperature higher by 5 to 20 ° C. than the melting point of the water-soluble resin. In addition, when adhered at room temperature, the coating resin layer surface 3μm
The following is moistened with water before lamination to dissolve a small amount of the water-soluble resin, and is laminated under the same pressure. The method of moistening with water is not particularly limited, but, for example, a method of continuously applying water to the coating resin surface with a roll, and then continuously laminating the surface of the copper-clad laminate, the water is sprayed. A method of continuously spraying onto the surface of the coating film and then continuously laminating it on the surface of the copper-clad laminate may be used.

The substrate-reinforced multilayer board is first impregnated with a thermosetting resin composition and dried to form a B stage.
Create a prepreg. Next, a predetermined number of the prepregs are stacked, a copper foil is arranged on at least one side, and laminated under heat and pressure to form a copper-clad laminate. The thickness of the copper foil of the inner and outer layers is preferably 5 to 18 µ.

The multilayer board is obtained by forming a circuit on a copper-clad laminate reinforced with a base material, and after treating the surface of the copper foil, at least one surface of the prepreg is a B-stage reinforced prepreg or a resin sheet or a resin sheet not reinforced with a base material. A copper-clad multilayer board is used in which a copper foil with a coating, a resin layer formed by coating with a paint, etc. are arranged, and if necessary, a copper foil is placed on the outside thereof and laminated by heating, pressing, preferably under vacuum.

The copper-clad laminate or multilayer board has a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol on at least the surface of the copper foil where the carbon dioxide laser is irradiated, at the hole forming position.
A resin composition containing 3 to 97% by volume, preferably 5 to 95% by volume of a metal compound powder of a total thickness of 30 to 200% on a thermoplastic film.
Attach to a thickness of μm. This is fixed to a copper foil surface that has not been treated with a tape or the like and adhered tightly, laminated by applying heat and pressure, and adhered to the surface, or water is added to the surface layer of the water-soluble resin composition, and room temperature is applied. , And dispose the water-soluble resin surface layer, and attach and adhere to it. From above, the copper foil is processed and drilled by directly irradiating a carbon dioxide laser beam of high output energy selected from 20 to 60 mJ / pulse, narrowed down to the target diameter.

When holes are formed by irradiating a carbon dioxide laser with an output of 20 to 60 mJ / pulse, burrs occur around the holes. This is not a problem in the present invention, and it is also possible to perform copper plating as it is to copper-plate 80% by volume or more of the inside of the hole, and at the same time, also plating the surface layer to connect the front and back layers and the inner layer copper foil. Preferably, after removing the resin layer remaining on the copper foil surface inside the hole generated by the processing, the inside of the hole is filled with copper plating by 80% by volume or more by copper plating, whereby the connection reliability is further improved. In addition, in order to form a very high-density circuit, it is necessary to make the surface copper foil thinner, and as a preferable method, both surfaces of the copper foil are mechanically planarized after carbon dioxide laser irradiation. Alternatively, etching is performed with a chemical solution to remove a part of the thickness of the original metal foil and, at the same time, remove burrs. The obtained copper foil is suitable for forming a fine pattern, and a through hole for through-hole plating in which the copper foil around the hole suitable for a high-density printed wiring board remains can be formed. In this case, etching is more preferable than mechanical polishing in terms of removing burrs from holes and dimensional change due to polishing.

The method of etching and removing copper burrs generated in the holes according to the present invention is not particularly limited. For example, Japanese Patent Application Laid-Open Nos. 02-22887, 02-22896, 02-25089 and 02-2.
5090, 02-59337, 02-60189, 02-166789, 03-25
995, 03-60183, 03-94491, 04-199592, 04-263
No. 488 discloses a method of dissolving and removing a metal surface with a chemical (referred to as a SUEP method). The etching rate is generally 0.02 to 1.5 μm / sec.

The carbon dioxide laser is in the infrared wavelength range.
Wavelengths of 9.3 to 10.6 μm are commonly used. Output is 20 ~ 6
The copper foil is processed and drilled at 0 mJ / pulse, preferably at 22 to 55 mJ / pulse.

When drilling through holes, 20
It is better to irradiate energy selected from ~ 60mJ / pulse. When removing the copper foil on the surface layer and the back surface, if a higher energy is selected, the number of irradiation shots can be reduced and the efficiency is good. When processing the intermediate resin layer, high output is not necessarily required, and it can be appropriately selected depending on the base material and the resin.
For example, the output can be selected from 5 to 35 mJ / pulse. Of course, high-power processing can be performed until the end. The processing conditions can be changed with or without the inner layer copper foil inside the hole.

In most cases, a resin layer having a thickness of 1 to 2 μm remains on the surface of the surface of the processed hole to which the resin of the surface copper foil has adhered. By removing this resin layer, the connection reliability between the copper plating and the copper in the inner and outer layers is improved. In order to remove the resin layer, generally known treatments such as desmear treatment can be performed.However, when the liquid does not reach the inside of the small-diameter hole, the removal residue of the resin layer remaining on the copper foil surface of the inner layer occurs. Connection failure with copper plating may occur. Therefore, more preferably, the inside of the hole is first treated in the gas phase to completely remove the residual layer of the resin, and then the inside of the hole is wet-treated, preferably by using ultrasonic waves. As the gas phase treatment, a generally known treatment can be used. For example, plasma treatment, low-pressure ultraviolet treatment, and the like can be given. As the plasma, low-temperature plasma in which molecules are partially excited by a high-frequency power source and ionized is used. These include high-speed processing using ion bombardment and gentle processing using radical species. As a processing gas, a reactive gas or an inert gas is used. As the reactive gas, oxygen is mainly used, and the surface is chemically treated. As the inert gas, an argon gas is mainly used. Using this argon gas or the like, physical surface treatment is performed. Physical treatment uses ion bombardment to clean the surface. The low ultraviolet ray is an ultraviolet ray having a short wavelength region, and irradiates a short wavelength region having a peak at 184.9 nm and 253.7 nm, and decomposes and removes the resin layer. After that, since the resin surface is often made hydrophobic, it is preferable to perform the wet treatment using ultrasonic waves in combination with the copper plating, particularly in the case of small-diameter holes. The wet treatment is not particularly limited,
For example, an aqueous solution of potassium permanganate, an aqueous solution for soft etching and the like can be used.

Electrical conduction can be obtained even if the inside of the hole is not necessarily filled with copper plating by 80% or more. However, the adhesion to the inner layer copper foil varies, and the reliability is poor. As the copper plating, a generally known copper plating method can be adopted. However, in consideration of plating time, workability, and the like, a method using a pulse plating additive (manufactured by Nippon Rironal Co., Ltd.) suitable for hole filling is particularly suitable.

[0031]

The present invention will be specifically described below with reference to examples and comparative examples. Unless otherwise specified, “parts” indicates parts by weight. Example 1 900 parts of 2,2-bis (4-cyanatophenyl) propane,
100 parts of (maleimidophenyl) methane are melted at 150 ° C,
The mixture was reacted for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Add bisphenol A type epoxy resin (trade name: Epicoat 1001, Yuka Shell Epoxy Co., Ltd.)
) And 600 parts of a cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.) were uniformly mixed and dissolved. Further, as a catalyst, zinc octylate 0.4
Parts, mixed and dissolved, 500 parts of an inorganic filler (trade name: calcined talc BST- # 200, manufactured by Nippon Talc Co., Ltd.), and 8 parts of black pigment were added, and the mixture was uniformly stirred and mixed to obtain varnish A. Obtained. This varnish was impregnated into a glass woven fabric having a thickness of 100 μm and dried at 150 ° C. to prepare a prepreg B having a gel time (at 170 ° C.) of 120 seconds and a glass cloth content of 56% by weight. Further, prepreg C having a glass content of 44% by weight was prepared. A 12 μm-thick electrolytic copper foil was placed above and below the two prepregs B, and
Lamination molding was performed for 2 hours under a vacuum of 20 kgf / cm ² , 30 mmHg or less at 20 ° C. to obtain a double-sided copper-clad laminate D having an insulating layer thickness of 200 μm. Circuits were formed above and below this, and the copper foil surface was subjected to black copper oxide treatment. One prepreg C was placed above and below the double-sided copper-clad laminate, and a 12 μm electrolytic copper foil was placed on the outside of the prepreg C. The laminate was molded in the same manner to obtain a multilayer board. On the other hand, 800 parts of copper oxide powder (average particle diameter: 0.6 μm) was added to a varnish prepared by dissolving polyvinyl alcohol powder in water, and uniformly stirred and mixed. This was applied on one side of a 50 μm-thick polyethylene terephthalate film so as to have a thickness of 20 μm.
After drying for a minute, the auxiliary material E with a metal oxide content of 40% by volume
Was formed. Place the auxiliary material E on the multilayer board so that the resin surface faces the copper foil side, fix it with cellophane tape, and then use a direct carbon dioxide laser and output 40 mJ / pulse first.
1 shot, then 7 shots with output 28mJ / pulse
Finally, irradiate one shot at 40mJ / pulse, and the hole diameter is 100μ
A total of 70 blocks of through holes for through holes were drilled with 900 holes in a 50 mm square of 50 m square. The burrs of the copper foil around the hole were removed by the SUEP treatment, and the copper foil on the surface was also dissolved to a thickness of 4 μm. This was placed in a plasma apparatus, and treated in an oxygen stream for 10 minutes and in an argon stream for 5 minutes, and then wetted with an aqueous potassium permanganate solution in an ultrasonic wave. Subsequently, the plate was plated with copper by a pulse electrolytic copper plating method (Nihon Rironal Co., Ltd.), and plated to 95% by volume or more of the through holes. This surface is polished, and the circuit (line / space = 100 / 100μ)
m), forming solder ball lands and the like, covering with a plating resist except for at least a semiconductor chip portion, a bonding pad portion, and a solder ball pad portion;
Gold plating was applied to create a printed wiring board. Table 1 shows the evaluation results of the printed wiring board.

Example 2 A metal compound powder (57% by weight of SiO ₂ , MgO 4) was added to an aqueous resin solution obtained by dissolving a water-soluble polyester resin having a melting point of 58 ° C. in water.
(3 wt%, average particle size: 0.4 μm), and uniformly stirred and mixed. Then, this was applied to a 25 μm polyethylene terephthalate film to a thickness of 40 μm, dried at 110 ° C. for 25 minutes, and contained a metal compound. A 70% by volume film-form auxiliary material F was prepared. On the other hand, one prepreg B of Example 1 was used, and a 7 μm electrolytic copper foil was placed above and below this prepreg B, and was similarly laminated and molded to obtain a double-sided copper-clad laminate. The hole-forming auxiliary material F was placed thereon, and laminated with a roll at 70 ° C. at a linear pressure of 15 kgf to form a coating film having good adhesion. From above, the output of carbon dioxide laser is 40mJ /
Irradiation was performed with a pulse for three shots to drill through holes. The auxiliary sheet of the surface layer was peeled off, put in a plasma apparatus without performing the SUEP treatment, and treated for 10 minutes in an oxygen stream and further for 5 minutes in an argon stream, and then ultrasonically treated with a potassium permanganate aqueous solution. Wet treatment is performed in combination, pulse copper plating is performed in the same manner, the inside of the through hole is filled with copper plating of 95% by volume or more, the surface is mechanically polished, and processed as in Example 1, to produce a printed wiring board did. Table 1 shows the evaluation results.

Comparative Example 1 The copper-clad board of Example 2 was used, and no auxiliary material was used on the surface.
Drilling was performed in the same manner with a carbon dioxide laser, but no holes were drilled.

Comparative Example 2 Using the multilayer board of Example 1, the copper foil on the front and back surfaces was etched away with a hole diameter of 100 μm, and the carbon dioxide laser energy was 15 mJ.
Drilled with the same number of shots in / pulse,
Fluff of glass fiber was found on the wall of the hole, the copper foil of the inner layer could not penetrate, and a through hole for a through hole could not be formed.

Comparative Example 3 2,000 parts of epoxy resin (trade name: Epikote 5045), 70 parts of dicyandiamide, and 2 parts of 2-ethylimidazole were dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and the insulating inorganic filler of Example 1 was further dissolved. Was added and mixed with stirring to obtain a varnish. This is thickness 100
A glass woven cloth of μm was impregnated and dried to obtain a prepreg G having a gelation time of 140 seconds (at 170 ° C.) and a glass content of 55% by weight, and a prepreg H having a gelation time of 180 seconds and a glass content of 43% by weight. . Using one piece of this prepreg G, place 12μm electrolytic copper foil on both sides, under vacuum of 190 ° C, 20kgf / cm ² , 30mmHg or less
Laminate molding was performed for 2 hours to obtain a double-sided copper-clad laminate I. This laminate
The drilling auxiliary material E of Example 1 was placed on I, and a hole was drilled similarly to form a through hole. Normal copper plating was performed at 20 μm without performing the SUEP treatment and without performing the gas phase treatment. Table 1 shows the evaluation results.

Comparative Example 4 Using the multilayer plate of Example 1, through holes were similarly drilled at 300 μm intervals using a mechanical drill having a drill diameter of 200 μm at a rotation speed of 100,000 rpm and a feed rate of 1 m / min. Without performing SUEP processing,
A desmear treatment was performed once without performing a gas phase treatment, and then copper plating was performed by a normal method at 20 μm to produce a printed wiring board. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 5 Using the same double-sided copper-clad plate D produced in Example 1, the upper and lower copper foils were removed by etching so that the through holes in the inner layer had a hole diameter of 100 μm. After forming a circuit on the copper foil, the surface of the copper foil was treated with black copper oxide, prepreg C was placed on both sides thereof, and a 12 μm electrolytic copper foil was placed on both sides thereof, and laminated and formed in the same manner as in Example 1. To make a four-layer plate. Using this multilayer board, 900 holes having a hole diameter of 100 μm were formed in the position of the surface where the through hole was to be formed by etching the copper foil. Similarly, 900 holes having a hole diameter of 100 μm were formed at the same position on the back surface (FIG. 4A). Using a carbon dioxide laser from the surface, a total of 63,000 holes, 70 blocks of 900 patterns,
10 shots were applied at an output of 15 mJ / pulse, and a through-hole for a through-hole was drilled [Fig. 4, (2)]. Thereafter, in the same manner as in Comparative Example 4, a desmear treatment was performed once without performing the SUEP treatment, and a copper plating was performed to a thickness of 20 μm [FIG. 4, (3)]. It was created. Table 1 shows the evaluation results.

[0038] Table 1 Item implementation example comparisons Example 1 2 3 4 5 sides hole positions of shift 0 0 0 0 25 ([mu] m) deviation of hole position of the inner layer 0 over over 0 35 ([mu] m) Pattern breakage and 0 / 200 0/200 14/200 15/200 17/100 Short (piece) Copper foil around land No No No No No Yes Glass transition temperature 235 233 139 235 235 (235) Through-hole heat cycle test (%) 100 cycle 1.1 1.3 3.7 1.0 2.9 300 cycles 1.2 1.4 37.5 1.2 4.5 500 cycles 1.3 1.4> 50 1.4 26.9 drilling time 27 10 @ 630 chromatography (min) migration resistance (Omega) normal 4x10 ¹³ over 6x10 ¹³ 5x10 ¹³ over over 200hrs 5x10 ¹²ー <10 ⁸ <10 ⁸ 500hrs.5x10 ¹¹ー 700hrs.3x10 ¹¹ 1000hrs.1x10 ¹¹

<Measurement Method> 1) Misalignment of Hole Position and Hole Drilling Time A hole of 100 μm in diameter was 900 holes / block and 70 blocks (63,000 holes in total) were formed within a 250 mm square work size. Drilling was performed with a carbon dioxide gas laser and a mechanical drill, and the time required for drilling 63,000 holes in one copper clad plate and the maximum value of the deviation between the front and back and the inner layer copper foil were shown. 2) Circuit pattern cut and short circuit In Examples and Comparative Examples, a board without holes was created in the same manner, a comb pattern of line / space = 100/100 μm was created, and then 200 patterns were etched with a magnifying glass. Was visually observed, and the total of the broken pattern and the short-circuited pattern was shown in the molecule. 3) Glass transition temperature Measured by the DMA method. 4) Through hole heat cycle test Create a land diameter of 250 μm for each through hole hole, connect 900 holes alternately front and back, one cycle is 260 ° C, solder, immersion 30 seconds → room temperature, 5 minutes, up to 500 cycles The maximum value of the rate of change of the resistance value was shown. 5) Copper foil break around land When a land with a diameter of 150 μm was formed around the hole, chipping of the copper foil at the land was observed. 6) Migration resistance One through hole with a hole diameter of 150 μm and a hole diameter of 100 μm is connected independently, and 500 of these are connected in parallel.
00 sets were prepared, treated at 85 ° C., 85% RH, and 50 VDC for a predetermined time, taken out, and the insulation resistance between through holes was measured. Drilling was performed with a hole diameter of 200 μm.

[0040]

According to the present invention, a high-output energy carbon dioxide laser selected from 20 to 60 mJ / pulse is directly applied to the copper surface of a copper-clad board having at least two copper layers. When drilling a copper foil, apply a metal oxide treatment to the copper foil surface of the copper-clad plate to be irradiated with a carbon dioxide gas laser, or use at least a melting point of 900 ° C as a drilling auxiliary material.
And a resin film containing a metal compound powder having a binding energy of 300 kJ / mol or more, a carbon powder, or a resin composition containing 3 to 97% by volume of a metal powder, having a total thickness of 30 to 200 μm. The adhered sheet is arranged, preferably adhered to the copper foil surface, through which a carbon dioxide laser is directly irradiated to form a through hole, and then the inside of the hole is subjected to a gas phase treatment to adhere to the copper foil surface. A method for manufacturing a printed wiring board having excellent connection reliability between a surface layer copper foil and a copper foil inside a hole by removing the resin layer and then performing a wet treatment, and thereafter filling 80% by volume or more of the inside of the hole with copper plating. Is provided. According to the manufacturing method of the present invention, a through-hole for through-holes without displacement of the hole positions on the front and back of the copper-clad plate is obtained, and the through-holes are formed at a processing speed several tens times faster than when drilling with a mechanical drill. It can be formed and productivity is greatly improved. Furthermore, by etching both surfaces of the copper foil two-dimensionally before the vapor phase treatment and etching away part of the thickness of the original copper foil, the burrs of the copper foil generated in the holes were simultaneously etched. A manufacturing method is provided that can be removed. As a result, even in the circuit formation of the front and back copper foil obtained by plating up with subsequent copper plating, high density and reliability without defects such as short-circuits and pattern breaks due to the thinner copper foil The present invention provides a printed wiring board having excellent characteristics.
Also, when the distance between the obtained through-hole walls is short, a material having excellent migration resistance can be obtained as compared with a material formed by drilling.

[Brief description of the drawings]

FIG. 1 is a process diagram of a through hole for a through hole (2) of a multilayer board of a first embodiment using a carbon dioxide laser, removal of burrs by a SUEP (3), and pulse copper plating (4).

FIG. 2 is a process diagram of drilling a through hole (2) and copper plating (3) of a double-sided copper-clad board of Example 2 using a carbon dioxide gas laser.

FIG. 3 is a process diagram of through-hole drilling (2) of a double-sided copper-clad board using a carbon dioxide gas laser and ordinary copper plating (3) of Comparative Example 3 (without SUEP).

FIG. 4 is a process diagram of drilling (2) and copper plating (3) of the multilayer board of Comparative Example 5 by using a carbon dioxide gas laser (SUE).
No P).

[Explanation of symbols]

a Copper foil b Glass cloth base thermosetting resin layer c Through-hole drilled by carbon dioxide laser d Through hole processed by SUEP e Copper plating filled in through-hole f Drilling auxiliary material E g Drilling Auxiliary material F h Copper foil etched by SUEP i Burr of surface copper foil generated j Through hole that is normally copper plated without SUEP treatment k Normal copper plating on through hole where front and back copper foil misalignment occurred Hole plated by the method l Internal copper foil misaligned

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05K 3/40 H05K 3/40 K // B23K 101: 38 (72) Inventor Yasuo Tanaka Shinjuku, Katsushika-ku, Tokyo 6-1-1 Mitsubishi Mitsubishi Chemical Co., Ltd. Tokyo Plant F-term (reference) 4E068 AF00 AJ01 AJ04 CA01 DA11 5E317 AA24 BB12 CC25 CC33 CD27 CD32 5E346 AA42 CC32 DD24 EE13 FF07 FF14 GG15 HH07

Claims (3)

[Claims] 1. A copper foil surface of a multilayer board having at least two or more copper layers, as a drilling auxiliary material, at least a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol.
After disposing a resin composition layer containing 3 to 97% by volume of one or more components of the above metal compound powder, carbon powder, or metal powder, or after treating the copper foil surface with a metal oxide metal, the copper foil Is irradiated with a carbon dioxide laser by the pulse oscillation of the carbon dioxide laser using energy selected from 20 to 60 mJ / pulse sufficient to remove After forming the hole and then removing the resin layer adhering to the copper foil surface inside the hole, 80 volume of the hole volume
A method for manufacturing a printed wiring board having excellent through-hole reliability, characterized by using a copper-clad board obtained by filling at least% with copper plating for a printed wiring board. 2. The printed wiring according to claim 1, wherein a part of the surface copper foil is dissolved with a chemical solution to make the thickness of the remaining copper foil 3 to 7 μm before plating the holes. Plate manufacturing method. 3. The printed wiring board according to claim 1, wherein a plasma treatment is first performed and then a chemical treatment is performed to remove the resin layer attached to the surface of the copper foil inside the hole. Production method.