JPH11330667A - Auxiliary material for drilling carbon dioxide gas laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an auxiliary material for making a small diameter through holes or via holes in a copper clad plate accurately at high speed by irradiating it with high output carbon dioxide gas laser. SOLUTION: A thin film or sheet-like auxiliary material of organic matter containing 3-97 vol.% of one or more kind of component including metal compound powder having melting point at 900 deg.C or above and bonding energy of 300 kJ/mol or above and carbon powder is arranged on a copper clad plate and irradiated, from above, with carbon dioxide gas laser having output energy selected in the range of 20-60 mJ/pulse. Consequently, a hole can be made in the surface copper foil and a through hole or a via hole having good wall can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary material used for directly irradiating a copper surface of a copper clad board having at least one copper layer with a carbon dioxide gas laser to form a hole. More specifically, copper-clad boards, copper-clad boards such as multilayer boards,
The present invention relates to an auxiliary material for forming a through hole or a via hole for a through hole. The copper-clad board and the multilayer board obtained by the present invention are mainly used for small-sized printed wiring boards for high-density semiconductor plastic packages 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 become smaller than 0.15 mmφ. When such a small hole is drilled, the drill diameter is so small that the drill bends or breaks at the time of drilling, and the processing speed is slow. This has caused problems in productivity, reliability, and the like. In addition, when irradiating a carbon dioxide gas laser, direct irradiation of the copper foil surface with the carbon dioxide gas laser reflects the laser beam and does not form a hole. Conventionally, the surface copper foil is first etched to a predetermined size. Then, the exposed portion of the resin was processed by irradiating a carbon dioxide laser thereto, thereby forming a via hole. In this case, when a small-diameter hole having a diameter of 100 μm or less is etched in the copper foil, defects such as poor hole diameter accuracy are found when the copper foil is thick. Also, when drilling through holes for through holes, use a negative film on the upper and lower copper foils in advance and drill holes of the same size by a predetermined method, and use a carbon dioxide laser to form through holes that penetrate the upper and lower sides. In this case, the positions of the upper and lower holes are displaced, and there are disadvantages such as difficulty in forming a land.

[0003]

SUMMARY OF THE INVENTION The present invention provides an auxiliary material for forming a small diameter through hole for a through hole and a via hole for a carbon dioxide gas laser for forming a via hole.

[0004]

According to the present invention, a resin composition having a melting point of 900 ° C. or more and a binding energy of 300 kJ /
A paint containing 3 to 97% by volume of one or more kinds of metal compound powder or carbon powder of 3 mol% or more, or a sheet-like processing auxiliary material formed by applying this to a thermoplastic film or the like, has a total thickness of 30 to By arranging the copper foil with a thickness of 200 μm on the surface of the copper foil, it is possible to easily make holes in the copper foil of the copper clad board. That is, according to the present invention, a carbon dioxide laser having an energy selected from the output of a carbon dioxide laser of 20 to 60 mJ / pulse is directly radiated to the copper foil surface by pulse oscillation to form a through hole for a through hole.
/ Process the copper foil with one of the energies in the pulse, stop when it reaches the resin layer, then output 20 ~ 35mJ
/ Pulse or reduce the output, process the resin layer at less than 20mJ / pulse, preferably 5-19mJ / pulse, and use it by arranging it on the surface copper foil when forming via holes To provide processing auxiliary materials. It is also possible to stack several sheets of processing auxiliary material and copper-clad boards alternately, or to place the processing auxiliary material on top and place several copper-clad boards underneath, and process with a carbon dioxide gas laser from above It is. After processing, the surface of the copper foil can be deburred by mechanical polishing,
In order to completely remove burrs, both surfaces of the copper foil are etched in a plane, and the thickness of the original metal foil is removed by etching to remove copper burrs that overhang the holes. Then, a through hole for a through hole in which the copper foil remains around the holes on both surfaces is formed. Form a hole as described above,
In addition, by deburring, the lands can be formed without shifting the copper foil positions of the upper and lower holes, the through holes can be formed without bending up and down, and since the copper foil becomes thin, the subsequent metal plating It is possible to produce a high-density printed wiring board free of defects such as short-circuits and pattern breaks in the formation of a fine wire circuit of the front and back copper foils obtained by plating up. In addition, the processing speed is much faster than when a mechanical drill is used, the productivity is good, and the economy is excellent.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses a carbon dioxide laser having an energy selected from 20 to 60 mJ / pulse sufficient to remove copper foil, and at least one layer, preferably two or more layers.
In the drilling of copper foil with a carbon dioxide gas laser of a copper-clad board with a through hole, a via hole, etc., especially a small-diameter hole in a copper-clad board having more than one copper layer, the copper foil surface irradiated with laser The present invention provides a drilling auxiliary material comprising a paint or a sheet in which a metal compound or a carbon powder and an organic substance are mixed, which is disposed in the above. By directly irradiating the surface of the auxiliary material with a carbon dioxide laser and processing and removing the copper foil, a through hole for a through hole and a via hole are formed or the formation thereof is facilitated.

[0006] The copper-clad board used in the present invention is a copper-clad board having one or more layers, preferably two or more layers of copper. Thermosetting resin copper-clad laminate of the material, using the copper-clad laminate for the inner layer, copper foil with resin or inorganic, organic base material reinforced thermosetting resin layer on the outside, and further on the outside, It includes a copper-clad board of a generally known configuration such as a multilayer board obtained by laminating and forming a copper foil as necessary. In addition, generally known materials such as a copper-clad board or a multilayer board in which a copper foil is bonded to a heat-resistant film such as a polyimide film, a polyester film, or a polyparabanic acid film can also be used.

As the substrate, generally known woven or nonwoven fabrics of inorganic or organic fibers can be used. Specifically, examples of inorganic fibers include E, A, C, L, M, S, D, N, quartz glass, and the like, and these may be used alone or in combination. Examples of the organic fibers include wholly aromatic polyamides and liquid crystal polyesters.

The resin of the thermosetting resin composition used in the present invention includes generally known thermosetting resins. Specific examples include an epoxy resin, a polyfunctional cyanate resin, a polyfunctional maleimide-cyanate resin, a polyfunctional maleimide resin, and an unsaturated group-containing polyphenylene ether resin. These are used alone or in combination of two or more. A thermosetting resin composition having a glass transition temperature of 150 ° C. or higher is preferable in order to make the shape of a through-hole processed by irradiation of a high-output carbon dioxide laser appropriate. Further, in consideration of moisture resistance, migration resistance, electric characteristics after moisture absorption, and the like, a polyfunctional cyanate ester resin composition is preferable.

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-cyanatophenyl) 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 43-18
468, 44-791, 45-11712, 46-4112, 47
-26853 and JP-A-51-63149 can also be used. Further, the molecular weight of the polyfunctional cyanate compound having a triazine ring formed by trimerization of a cyanato group of
0-6,000 prepolymers are also used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer using, for example, an acid such as a mineral acid or a Lewis acid; a base such as a sodium alcoholate or a tertiary amine; a salt such as sodium carbonate as a catalyst. 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. The thermosetting resin is usually used by dissolving it 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 group-containing silicone resin with an ephalohydrin, 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 polyamide, 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 an appropriate combination 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, fluoro rubber, natural rubber; polyethylene, polypropylene,
Polybutene, poly-4-methylpentene, polystyrene, AS resin, ABS resin, MBS resin, styrene-isoprene rubber, polyethylene-propylene copolymer,
-Fluorinated ethylene-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 appropriately used. In addition, other known organic fillers, dyes, pigments, thickeners, lubricants, defoamers, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, thixotropic agents And various other additives are used in combination as needed. If necessary, a curing agent and a catalyst are appropriately added to the compound having a reactive group.

The thermosetting resin composition of the present invention is itself cured by heating, but has a low curing rate, and is inferior in workability, economy and the like. Therefore, a known thermosetting catalyst can be used for the thermosetting resin used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 part by weight, per 100 parts by weight of the thermosetting resin.
~ 5 parts by weight.

For use in the drilling aid of the present invention;
As the metal compound and carbon powder having a melting point of 900 ° C. or more and a binding energy of 300 kJ / mol or more, generally known ones can be used. Specifically, as the oxide, titanias such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide,
Zinc oxides such as manganese dioxide and zinc oxide, silicon dioxide, aluminum oxide, rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, tungsten oxides such as tungsten oxide, copper such as copper oxide Oxides and the like. Examples of the non-oxide include generally known ones such as silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, barium sulfate, and rare earth oxysulfide. In addition, carbon can also be used. Furthermore, various glasses are also mentioned as a kind of metal compound. These may be used alone or in combination of two or more. It is preferable that the dissociation material and the like adhere to the hole walls and the like due to the dissociation of the molecules by the irradiation of the carbon dioxide gas laser, and do not adversely affect the adhesion to the hole walls of the semiconductor chip and copper plating. Na,
K, Cl ions and the like particularly adversely affect the reliability of the semiconductor, and therefore those containing these components are not suitable. The compounding amount is 3 to 97% by volume, preferably 5 to 95% by volume in the auxiliary material.
Is used, and is usually a powder having a particle size of 5 μm or less, which is blended with an organic substance, particularly a resin composition, and is uniformly dispersed. Particle size is 1
μm or less is particularly preferred.

The organic material of the auxiliary material is not particularly limited, but is selected from those which do not peel off when kneaded and applied to the surface of a copper foil and dried, or when applied to a thermoplastic film or the like to form a sheet. . Preferably, a resin is used. In particular, in consideration of the environment or cleaning of the copper foil surface after processing, a water-soluble resin such as polyvinyl alcohol, polyester, or starch is preferably used.

The method for preparing a composition comprising a metal compound powder or a carbon powder and a resin is not particularly limited.
A method of kneading at high temperature with no solvent in a kneader or the like, extruding into a sheet form, using a resin composition dissolved in a solvent or water, adding a metal compound powder or carbon powder thereto, uniformly stirring and mixing, and using this as a paint A method of forming a film by coating and drying on a copper foil surface, a method of directly spraying on a copper foil surface with a spray, a method of coating and drying a film to form a sheet,
A generally known method such as a method of impregnating an organic or inorganic substrate and drying to obtain a sheet containing the substrate can be used.

As the outermost copper foil of the copper clad board, generally known ones can be used. Preferably, an electrolytic copper foil having a thickness of 3 to 18 μm is used.

The substrate-reinforced copper-clad laminate 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 used, a copper foil is arranged on at least one side, and lamination molding is performed under heating and pressure to obtain a copper-clad laminate.

The copper-clad board or the multi-layer board contains at least 3 to 97% by volume, preferably 5 to 95% by volume of metal compound powder or carbon powder on the surface of the copper foil at the hole forming position on the surface irradiated with the carbon dioxide laser. A coating or sheet formed of a resin composition, preferably having a total thickness of 30 to 200 μm, is disposed. From above, squeezed to the desired diameter, 20-60
By irradiating a high-output one-energy carbon dioxide laser beam selected from mJ / pulse, the copper foil is processed and drilled.

When a hole is formed by irradiating an energy selected from an output of 20 to 60 mJ / pulse with a carbon dioxide laser, burrs are generated around the hole. Therefore, after irradiating the carbon dioxide gas laser, both surfaces of the copper foil are etched two-dimensionally,
By etching away part of the thickness of the original metal foil, burrs are also etched away at the same time. As a result, the obtained copper foil is suitable for forming a fine pattern, and a through hole or a via hole for a through hole in which the copper foil around the hole suitable for a high-density printed wiring board remains.

The method of etching and removing the copper burrs generated in the holes and the copper foil on the front and back sides is not particularly limited. For example, JP-A-02-22887, JP-A-02-22896, JP-A-02-25089,
02-25090, 02-59337, 02-60189, 02-16678
9, 03-25995, 03-60183, 03-94491, 04-19
A method of dissolving and removing the metal surface with a chemical (referred to as a SUEP method) disclosed in JP-A-9592 and 04-263488 is adopted. The etching rate is generally 0.02 to 1.0 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 22-50 mJ / pulse.

[0025]

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 bis (4-maleimidophenyl) methane was melted at 150 ° C. and reacted with stirring for 4 hours to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. 400 parts of bisphenol A type epoxy resin (trade name: Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) and cresol novolak type epoxy resin (trade name: ESCN-220F, Sumitomo Chemical Co., Ltd.)
Was added and uniformly dissolved and mixed. Further, 0.4 part of zinc octylate is added as a catalyst, and the mixture is dissolved and mixed. 500 parts of an inorganic filler (trade name: calcined talc BST- # 200, manufactured by Nippon Talc Co., Ltd.) and 8 parts of a black pigment are added, and the mixture is uniformly mixed. The varnish A was obtained by stirring and mixing. This varnish is 100μ thick
m, and dried at 150 ° C. to prepare a prepreg (prepreg B) having a gelling time (at 170 ° C.) of 120 seconds and a glass cloth content of 54% by weight. The 12 μm-thick electrolytic copper foil was placed above and below the four prepregs B, and
The laminate was molded under a vacuum of 20 kgf / cm ² and a pressure of 30 mmHg or less for 2 hours to obtain a double-sided copper-clad laminate B having an insulating layer thickness of 400 μm.

On the other hand, 800 parts of copper oxide powder (average particle diameter: 0.9 μm) as a metal compound was added to a varnish in which polyvinyl alcohol powder was dissolved in water, and uniformly mixed by stirring (varnish D). This is placed on the double-sided copper-clad laminate C with a thickness of
m and dried at 110 ° C. for 30 minutes to form a film having a copper oxide powder content of 13% by volume (FIG. 1 (1)).
From above, 900 holes of 300 μm in diameter and 100 μm in diameter were directly applied with 8 pulses (shots) at an output of 40 mJ / pulse of a carbon dioxide gas laser, and 70 blocks of through-holes were drilled (FIG. 1 (2)). . The coating film on the surface was washed and removed with warm water at 60 ° C., and the copper foil burr around the hole was dissolved and removed by the SUEP method, and the copper foil on the surface was also dissolved to 7 μm (FIG. 1 (3)). This plate is plated with copper by 15μm in the usual way.
(Total thickness: 22 μm) (FIG. 1 (4)). All of the land copper foil around this hole remained. The circuit (line / space = 50/50 μm is 200
), Solder ball lands, etc., and excluding at least the semiconductor chip mounting portion, the bonding pads, and the solder ball pads, covered with a plating resist, and plated with nickel and gold to produce a printed wiring board. Table 1 shows the evaluation results of the printed wiring board.

Example 2 A metal compound (57% by weight of SiO ₂ , 43% by weight of MgO) was placed in an aqueous resin solution comprising polyvinyl alcohol and starch.
%, Average particle diameter: 0.4 μm) and uniformly stirred and mixed, and then applied to a 150 μm polyethylene terephthalate film so as to have a thickness of 20 μm.
After drying for minutes, a film-shaped auxiliary material E having a metal compound powder content of 90% by volume was obtained. On the other hand, 700 parts of epoxy resin (trade name: Epikote 5045) and epoxy resin (trade name: E
(SCN220F) 300 parts, dicyandiamide 35 parts, 2-ethyl-
1 part of 4-methylimidazole is dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, and 800 parts of calcined talc (trade name: BST- # 200) are used.
Then, the mixture was forcibly stirred and uniformly dispersed to obtain Varnish F.
This was impregnated into a glass woven cloth having a thickness of 100 μm and dried to prepare a prepreg (prepreg G) having a gelling time of 150 seconds and a glass cloth content of 55% by weight. Using two pieces of this prepreg G, place 12 μm electrolytic copper foil on both sides,
Laminate molding was performed for 2 hours under a vacuum of f / cm ² and 30 mmHg or less to prepare a double-sided copper-clad laminate H. The thickness of the insulating layer was 200 μm. One piece of the auxiliary material H and two pieces of the copper-clad laminate H were placed under the auxiliary material H, and the pulse was irradiated with 10 pulses at an output of 30 mJ / pulse of a carbon dioxide laser to form a through hole for a through hole having a hole diameter of 80 μm. The surface was subjected to the SUEP process, circuit formation, and the like in the same manner as in Example 1 to obtain a printed wiring board. Table 1 shows the evaluation results.

Example 3 A varnish I containing 50% by volume of carbon (average particle size: 0.35 μm) in a polyvinyl alcohol aqueous solution was used, and the varnish I was similarly applied to a 25 μm-thick polyethylene terephthalate film. It dried and the auxiliary | assistant sheet J for drilling which formed the coating film of thickness 37 micrometers was obtained. On the other hand, a 12 μm electrolytic copper foil was placed above and below one prepreg B of Example 1, circuits were formed above and below a double-sided copper-clad laminate similarly laminated and formed, and black copper oxide treatment was performed. Prepreg B was placed thereon, and a 12 μm electrolytic copper foil was placed outside the prepreg B, and similarly laminated and molded to form a four-layer double-sided copper-clad multilayer board. The perforated auxiliary sheet J was placed on this surface, and 9 pulses were irradiated at a carbon dioxide laser output of 40 mJ / pulse to form a through-hole. After the SUEP process,
A printed wiring board was prepared by performing panel copper plating, forming circuits vertically and performing noble metal plating in the same manner as in Example 1. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 1 Using the double-sided copper-clad laminate C of Example 1, without forming a coating film on the surface, directly drilling holes on the copper foil surface with a carbon dioxide laser in the same manner as in Example 1. Performed, but no holes were drilled.

Comparative Example 2 Using the double-sided copper-clad laminate C of Example 1, the surface of the copper foil where the holes were to be drilled was painted with black magic, and the carbon dioxide laser was similarly irradiated, but no holes were formed. Was.

Comparative Example 3 In Example 2, Epicoat 5045 was used as an epoxy resin.
Using 1,000 parts alone, using the double-sided copper-clad laminates prepared in the same way, placing the auxiliary material E on the copper foil surface,
Similarly, 50 shots were irradiated with a carbon dioxide laser at an output of 17 mJ / pulse, and a through hole for a through hole having a hole diameter of 80 mm was formed. In this hole wall, glass fiber was partially found in the hole, and the hole shape was not a perfect circle but an elliptical shape. After that, Example 2
Copper plating, circuit formation, etc. were performed in the same manner as described above to produce a printed wiring board. Table 1 shows the evaluation results. In this example, processing by the SUEP method was not performed.

Comparative Example 4 Using the double-sided copper-clad laminate C of Example 1, with a mechanical drill having a diameter of 100 μm, at a rotation speed of 100,000 rpm and a feed rate of 1 m / min, holes were formed at 300 μ intervals in the same manner as in Example 1. Opened. Example 1
In the same manner as described above, copper plating was performed at 15 μm, and a circuit was formed on the front and back sides to prepare a printed wiring board. In this example, SUE
The treatment by the P method was not performed. Two drill breaks occurred on the way. Table 1 shows the evaluation results.

COMPARATIVE EXAMPLE 5 An interval of 300 μm was formed on the copper foil surface of the double-sided copper-clad laminate C of Example 1.
Then, 900 holes with a hole diameter of 100 μm are etched and drilled in the copper foil, and similarly, holes with a hole diameter of 100 μm are formed in the same position on the back surface as well.
Opened 00 pieces. (FIG. 3 (1)). Eight pulses (shots) of 70,000 blocks per pattern and 63,000 holes in total were applied from the surface with a carbon dioxide laser at an output of 40 mJ / pulse, and through holes for through holes were drilled (Fig. 3 (2)). . Thereafter, copper plating was performed at 15 μm in the same manner as in Comparative Example 4 (FIG. 3).
(3)) A circuit was formed on the front and back, and a printed wiring board was prepared in the same manner. In this example, as in Comparative Example 4, SUEP
The treatment by the method was not performed. Table 1 shows the evaluation results.

<Measurement method> 1) Displacement of front and back hole positions and drilling time Holes with a diameter of 80 μm or 100 μm in a work size of 250 mm square were set as 900 holes / block with 70 blocks (63,000 holes total).
Hole) created. Drilling was performed with a carbon dioxide laser and a mechanical drill, and the time required for drilling 63,000 holes in one copper-clad laminate and the maximum value of the deviation between the hole positions on the front and back were shown. 2) Circuit pattern break and short circuit The pattern of line / space = 50 / 50μm of the printed wiring board prepared in the examples and comparative examples is visually observed with a magnifying glass after etching 200 patterns. The sum of the shorted patterns is shown in the numerator.
3) Glass transition temperature Measured by the DMA method. 4) Through-hole / Heat cycle test A 200-μm diameter land is created in each through-hole, 900 holes are connected alternately on the front and back, and one cycle consists of 260 cycles of 260 ° C, solder, immersion for 30 seconds → room temperature for 5 minutes, 200 cycles Then, the maximum value of the rate of change in resistance was shown.

Table 1 Item Example Example Comparative Example 1 2 3 3 4 5 Front and back hole position deviation (μm) 0 0 0 0 0 0 Hole shape Round Circular Round Elliptical Circular Circular Round Hole wall shape Straight line Straight Large irregularities Nearly straight line pattern Cut and short (number) 0/200 0/200 0/200 55/200 57/200 57/200 Glass Tg (° C) 235 160 235 139 235 235 Through-hole heat cycle test (%) 2.5 3.8 2.8 25.9 2.6 5.0 Drilling time (min) 24 15 26-630-Note: The hole shape of Comparative Example 5 was circular at the top but deformed at the bottom. In all the examples, both the top and bottom were circular.

[0037]

The present invention relates to a method for directly irradiating a copper surface of a copper-clad board having at least one copper layer with a high-power one-energy carbon dioxide gas laser to form a copper foil. As a drilling auxiliary material disposed on the copper foil surface of the copper-clad board irradiated with the carbon dioxide laser, at least the melting point
Provided is an organic substance containing metal compound powder having a binding energy of 300 kJ / mol or more at 900 ° C. or more or carbon powder in an amount of 3 to 97% by volume. The organic substance of the present invention, which is mainly composed of a resin composition, is provided with a coating film or sheet having a total thickness of 30 to 200 μm on the copper foil surface. There is no need to remove the copper foil by etching, and in the through hole for the through hole, there is no displacement of the hole position on the front and back of the copper clad board, and it can be processed at a processing speed several tens times faster than drilling with a mechanical drill. Yes, productivity can be greatly improved. Also, by using the auxiliary material for drilling of the present invention, drilling of copper foil by a carbon dioxide gas laser becomes easy, but burrs are generated around the hole. By post-etching both surfaces of the copper foil two-dimensionally in the post-treatment and etching away part of the thickness of the original copper foil, the burrs of the copper foil generated in the holes can be removed by etching at the same time. Even in the circuit formation of the front and back copper foil obtained by plating up with copper plating, it is possible to create a high-density printed wiring board without occurrence of defects such as short circuit and pattern breakage, and obtain a highly reliable semiconductor package. did it.

[Brief description of the drawings]

FIG. 1 is a process diagram of a through hole for a through hole by a carbon dioxide gas laser of Example 1.

FIG. 2 is a process diagram of a through hole for a through hole by a carbon dioxide laser according to a third embodiment.

FIG. 3 is a process diagram of a through hole for a through hole by a carbon dioxide gas laser of Comparative Example 5.

[Explanation of symbols]

a resin layer containing metal compound powder b copper foil c thermosetting resin layer of glass cloth base material d through-hole perforated hole by carbon dioxide gas laser e generated burr f through-hole perforated hole with misalignment of front and back copper foil positions Part g Through-hole with copper plating without SUEP treatment

 ──────────────────────────────────────────────────の Continued from the front page (72) Inventor Yoshihiro Kato 6-1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi Gas Chemical Co., Ltd. Tokyo factory

Claims (2)

[Claims] 1. An energy selected from 20 to 60 mJ / pulse sufficient to remove a copper foil with a carbon dioxide laser,
A carbon dioxide laser is irradiated to the copper foil surface by pulse oscillation, and as a drilling auxiliary material used on the copper foil surface to form a hole by processing the copper foil of the copper clad board, at least the melting point is
One or more components of metal compound powder or carbon powder having a binding energy of 300 kJ / mol or more at 900 ° C or more
An auxiliary material for carbon dioxide laser drilling, characterized in that an organic thin film or sheet containing up to 97% by volume is used. 2. A thin film or sheet having a thickness of 30 to 200 μm.
The auxiliary material for drilling according to claim 1, wherein m is m.