JP2000061678A - Method for forming through hole by laser beam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming a small-diameter through hole on many copper-coated sheets at one time precisely, speedily and directly by gaseous CO2 laser only of one high output energy. SOLUTION: In the method for forming a through hole simultaneously on many copper-coated sheets having copper layers for at least two or more layers by using energy selected from 20-60 ml/pulse enough for removing a copper foil with the gaseous CO2 laser, through its pulse oscillation; an organic coat film or sheet is arranged containing one or more kinds of 3-97 vol.% o a metallic compound powder, which has a melting point of 900 deg.C or higher and a binding energy of 300 Kj/mol or above, a carbon powder or a metallic powder, at least on the copper foil surface to be irradiated with the gaseous CO2 laser, with the 2-10 sheets arranged in superposition, and with a through hole formed on many copper-coated sheets simultaneously by emitting the gaseous CO2 laser from above for necessary pulses. As a result, a through hole can be formed at high speed, enabling a printed circuit board to have a superior connecting reliability of the hole wall and an improved cost performance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to perforating a copper clad plate having at least two copper layers instead of a mechanical drill. More specifically, without removing the copper foil on the surface in advance, one energy of a high-power carbon dioxide gas laser is placed on the copper foil surface by using an auxiliary material, and a plurality of them are stacked and arranged directly from above. It relates to a method of irradiating a laser beam to open a through hole. The printed wiring board using the copper clad board obtained by this drilling is mainly used for small semiconductor plastic packages.

[0002]

2. Description of the Related Art Conventionally, in a high density printed wiring board used for a semiconductor plastic package or the like, a through hole for a through hole is drilled. In recent years, the diameter of drills has become smaller and smaller, and the hole diameter has become 0.15 mmφ or less.When drilling holes with such small diameters, the drill diameter is thin, so the drill bends, breaks, and the processing speed is high. However, there were drawbacks such as slowness, and there were problems with productivity, reliability, etc. Furthermore, using a negative film in advance on the upper and lower copper foils to make holes of the same size by a predetermined method, and when trying to form through holes that penetrate the upper and lower sides with a carbon dioxide laser, the positions of the upper and lower holes will be There are drawbacks such as deviation and difficulty in forming lands. in addition,
It was impossible to punch multiple holes at the same time. The thermosetting resin copper clad laminate of glass cloth base material has a problem that when the output of the carbon dioxide gas laser is small, it is difficult to process the glass and fluff remains on the hole wall, while the output is large. In this case, the hole wall was not linear, and the shape was a problem.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above problems and stacks a large number of copper clad plates on which auxiliary materials for drilling are arranged with the energy of a high-power carbon dioxide laser.
An object of the present invention is to provide a method for forming small-diameter holes at high speed and with high reliability of hole walls.

[0004]

According to the present invention, at least by pulse oscillation of a carbon dioxide gas laser using energy selected from the energy of 20 to 60 mJ / pulse, which is sufficient to remove a copper foil with a carbon dioxide gas laser. In a method of simultaneously forming a large number of through holes in a copper clad plate having two or more copper layers, a melting point of 900 ° C. or more and a binding energy of 30 at least on a copper foil surface irradiated with a carbon dioxide laser.
A coating film or sheet of an organic compound containing 0 to 9 KJ / mol or more of metal compound powder, carbon powder, or 3 to 97 vol% of one or more kinds of metal powder is arranged, and 2 to 10 sheets of these double-sided copper clad plates are stacked and arranged. Provided is a method for forming a hole in which through holes are simultaneously formed in a large number of copper-clad plates by irradiating a required pulse of carbon dioxide laser from above. After that, both surfaces of the copper foil are planarly etched, and the thickness of part of the original copper foil is removed by etching, and at the same time, the copper foil burr that overhangs in the hole is also removed by etching. By forming a through-hole plating hole in which the copper foil on both sides remains, the copper foil positions of the upper and lower holes do not shift, lands can be formed, and the through holes can be formed without bending up and down, and Since the copper foil becomes thinner, subsequent high-density printed wiring boards can be created without causing defects such as short circuits or pattern breaks in the circuit formation of the fine wires of the front and back copper foil obtained by plating up with metal plating. We were able to. In addition, the processing speed was remarkably faster than that obtained with a drill, the productivity was good, and the economy was excellent. After the through hole is opened, other than the method of etching with a chemical solution,
Although it is possible to polish the surface with a machine, it is preferable to etch with a chemical solution from the viewpoints of removing burrs and creating fine patterns. The holes can be formed not only in the double-sided copper clad laminate but also in a multilayer board obtained by using the same resin composition.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention employs an energy selected from a high-power carbon dioxide gas laser to directly irradiate a laser on a glossy surface of a copper foil of a copper clad plate with a melting point of 900 ° C. or more and a binding energy of 300 KJ / Arrange a coating film or sheet of an organic compound containing at least 3 mol% of metal compound powder, carbon powder, or 3 to 97 vol% of metal powder.
Zero sheets are arranged one on top of the other, and a necessary pulse of carbon dioxide gas laser is radiated from above to form through holes for through holes, especially small-diameter holes. The perforated printed wiring board is used for mounting a semiconductor chip. In this case, it is also possible to place an auxiliary material made of a water-soluble resin between all the copper clad plates, bond them with a heating roll, and then punch holes.

The double-sided copper clad board used in the present invention includes:
Although not particularly limited, for example, a double-sided copper clad plate having a glass cloth as a base material, a thermosetting resin composition mixed with an inorganic insulating filler, and having a homogeneous structure is preferably used. In addition, a copper clad board with a copper foil on a film such as polyimide film,
An organic fiber-based copper clad plate or the like may be used. Of course, a copper plate having a single copper layer can be punched as well. The thickness of the copper clad plate is not particularly limited, but is preferably 0.05 to 1.0 mm.

The substrate is not particularly limited, but as the inorganic fiber, a generally known glass woven fabric or nonwoven fabric can be used. Specifically, the glass fibers are E, S, D, N
Examples thereof include glass. The glass content is not particularly limited, but is generally 30 to 85 wt%. As an organic fiber,
For example, woven or non-woven fabric of wholly aromatic polyamide fiber, liquid crystal polyester fiber or the like is used. In addition, the polyimide film may be used as a base material and a resin layer may be attached to one surface or both surfaces of the polyimide film.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used. Specific examples thereof include epoxy resins, polyfunctional cyanate ester resins, polyfunctional maleimide-cyanate ester resins, polyfunctional maleimide resins, and unsaturated group-containing polyphenylene ether resins. One kind or two or more kinds. Are used in combination. A thermosetting resin composition with a glass transition temperature of 150 ° C or higher is preferable from the viewpoint of through-hole shape during processing with high-power carbon dioxide laser irradiation. Moisture resistance, migration resistance, electrical characteristics after moisture absorption, etc. From this point of view, a polyfunctional cyanate ester resin composition is preferable.

The polyfunctional cyanate compound which is the thermosetting resin component of the present invention is a compound having two or more cyanato groups in the molecule. To give a concrete example, 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 reaction of novolac with cyanogen halide. .

In addition to these, Japanese Examined Patent Publications 41-1928 and 43-18
468, same 44-4791, same 45-11712, same 46-41112, same 4
The polyfunctional cyanate ester compounds described in 7-26853 and JP-A-51-63149 can also be used. Moreover, the molecular weight of the polyazine having a triazine ring formed by trimerization of the cyanato group of these polyfunctional cyanate ester compounds is 400
~ 6,000 prepolymers are used. This prepolymer is obtained by polymerizing the above-mentioned polyfunctional cyanate ester monomer using, for example, acids such as mineral acid and Lewis acid; bases such as sodium alcoholate and tertiary amines; salts such as sodium carbonate and the like. It is obtained by The prepolymer also contains some unreacted monomer and is in the form of a mixture of the monomer and the prepolymer. Such a raw material is suitably used for the purpose of the present invention. Generally, it is used by dissolving it in a soluble organic solvent.

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

As the polyimide resin, a generally known one can be used. Specific examples thereof include reaction products of polyfunctional maleimides and polyamines, and polyimides having a terminal triple bond described in JP-B-57-005406.

Although these thermosetting resins can be used alone, it is preferable to use them in combination in consideration of the balance of properties.

Various additives may be added to the thermosetting resin composition of the present invention, if desired, within the range in which the original properties of the composition are not impaired. These additives include polymerizable double bond-containing monomers such as unsaturated polyester 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-methylpentene, polystyrene, AS resin, ABS resin, MBS resin, styrene-isoprene rubber, polyethylene-propylene copolymer, 4
-Fluorinated ethylene-6-fluorinated ethylene copolymers; high molecular weight prepolymers or oligomers such as polycarbonate, polyphenylene ether, polysulfone, polyester, polyphenylene sulfide; polyurethane and the like are exemplified and used appropriately. In addition, various other additives such as known organic fillers, thickeners, lubricants, defoamers, dispersants, leveling agents, photosensitizers, flame retardants, brighteners, polymerization inhibitors, thixotropic agents, etc. The agents are used in an appropriate combination as desired. If necessary, the compound having a reactive group is appropriately mixed with a curing agent and a catalyst.

The thermosetting resin composition of the present invention is itself cured by heating, but has a slow curing rate and is inferior in workability and economical efficiency. Therefore, a known thermosetting catalyst is used for the thermosetting resin used. Can be used. The amount used is 0.005 to 10 parts by weight, preferably 0.01 to 5 parts by weight, based on 100 parts by weight of the thermosetting resin.

As the inorganic insulating filler, generally known ones can be used. Specifically, silicas such as natural silica, calcined silica and amorphous silica; white carbon, titanium white, aerosil, clay, talc,
Examples thereof include wollastonite, natural mica, synthetic mica, kaolin, magnesia, alumina and perlite. The addition amount is 10 to 60 wt%, preferably 15 to 50 wt%.

Further, it is preferable to add a black dye or pigment to the resin so that the light is not dispersed by the irradiation of the carbon dioxide laser. The particle diameter is preferably 1 μm or less for uniform dispersion. As the type of dye and pigment, generally known insulating materials can be used. The addition amount is preferably 0.1 to 10 wt%. Further, glass fibers whose surface is dyed black can also be used.

A generally known copper foil can be used as the outermost copper foil. Preferably, an electrolytic copper foil or the like having a thickness of 3 to 18 μm is used. As the inner layer copper foil, an electrolytic copper foil having a thickness of 5 to 18 μm is preferably used.

The substrate-reinforced copper-clad laminate is prepared by first impregnating the above-mentioned substrate with the thermosetting resin composition and drying to obtain B stage,
Create a prepreg. Next, a predetermined number of the prepregs are used, copper foils are arranged on the upper and lower sides, and laminated under heat and pressure to form a double-sided copper clad laminate. The cross-section of this copper-clad laminate has a resin other than glass and an inorganic filler uniformly dispersed, and when laser-drilled, the holes are uniformly formed. Also,
The blacker one is that the laser light is not dispersed and there is no unevenness on the hole wall, and it is more uniform.

As the metal compound in the auxiliary material used for the surface of the copper foil used in the present invention, generally known compounds can be used. Specifically, the oxides include titanias such as titanium oxide, magnesia such as magnesium oxide, iron oxides such as iron oxide, nickel oxides such as nickel oxide, and copper oxides such as copper oxide. Examples thereof include manganese oxides such as manganese dioxide, zinc oxides such as zinc oxide, silicon dioxide, aluminum oxide, and cobalt oxide. Also,
Glass powders such as E, A, C, L, D, S, N and M are a mixture of the above metal compounds and can be used as the present auxiliary material. Examples of the non-oxide include silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, calcium carbonate, rare earth oxysulfide, and generally known ones. In addition, carbons are also used. Furthermore, silver, aluminum, bismuth, cobalt, copper, iron, manganese, molybdenum, nickel, vanadium, antimony, silicon, tin, titanium,
A simple substance such as zinc or a metal powder of an alloy thereof is used. These may be used alone or in combination of two or more. The compounding amount is 3 to 97 vol%, preferably 5 to 95 vol%.

It is preferable that the compound dissociates or scatters upon irradiation with a carbon dioxide laser and does not adversely affect the semiconductor chip, the adhesion to the hole wall, and the like. Since Na, K, Cl ions, etc., particularly adversely affect the reliability of the semiconductor, those containing these components are not suitable.

The organic material of the auxiliary material is not particularly limited, but is selected so that it does not peel off when kneaded and applied on the surface of the copper foil, dried, or formed into a sheet. Resins are preferably used. In particular, water-soluble resins such as polyvinyl alcohol, polyesters, polyethers, starches and the like, which are generally known, are preferably used from the viewpoint of environment.

The method for preparing the metal compound powder, the carbon powder, or the composition consisting of the metal powder and the organic material is not particularly limited, but a method of kneading at a high temperature with a solvent such as a kneader and extruding into a sheet, solvent or water. A resin composition that dissolves in, add the above powder to it, stir and mix evenly, and use this to coat the copper foil surface as a paint, dry it to make a film, and apply it to the film. Examples thereof include a sheet-shaped method.

Metal compound powder, on the surface of the copper foil at the hole forming position of at least the carbon dioxide laser irradiation surface of the copper clad plate,
A coating film or sheet made of a resin composition containing one kind or two or more kinds of carbon powder or metal powder is arranged, and a plurality of copper clad plates are placed, and a total of 2 to 10 sheets are stacked, and a direct purpose is obtained. Drilling is performed by irradiating a carbon dioxide laser with an energy selected from high output, which has been narrowed down to the diameter.
Of course, when the thickness of the copper clad plate is thin, it is possible to stack many sheets, but the number of laser pulse shots increases and the workability is poor. When drilling, auxiliary materials are generally used on the underside to stop the laser.

When a carbon dioxide gas laser is selected with an energy output of 20 to 60 mJ / pulse and irradiated to form a through hole, burrs are generated around the hole. Therefore, after the carbon dioxide laser irradiation, both surfaces of the copper foil were planarly etched to partially remove the thickness of the original metal foil, thereby simultaneously removing the burrs, and the obtained burrs were obtained. The copper foil is suitable for forming a fine pattern, and is suitable for a high-density printed wiring board, and forms a through hole for through-hole plating in which the copper foil on both sides around the hole remains.

The method of etching away the copper burr generated in the holes of the present invention is not particularly limited, but for example, JP-A-02-22887, 02-22896, 02-25089,
02-25090, 02-59337, 02-60189, 02-16
6789, same 03-25995, same 03-60183, same 03-94491, same
According to the method disclosed in JP-A-04-199592 and JP-A-04-263488 for dissolving and removing a metal surface with a chemical (referred to as the SUEP method). In this case, the etching rate is generally 0.02 to 1.0.
Performed at 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 ~
It is used at 60 mJ / pulse, preferably 22 to 50 mJ / pulse.

[0028]

The present invention will be specifically described below with reference to Examples and Comparative Examples. Unless otherwise specified, “part” means part by weight. Example 1 900 parts of 2,2-bis (4-cyanatophenyl) propane,
Add 100 parts of bis (4-maleimidophenyl) methane to 150 ° C.
Was melted and reacted for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. Bisphenol A
Type epoxy resin (trade name: Epicoat 1001, manufactured by Yuka Shell Epoxy Co., Ltd.) 400 parts, cresol novolac type epoxy resin (trade name: ESCN-220F, Sumitomo Chemical Co., Ltd.)
(Manufactured by Mfg. Co., Ltd.) was added and uniformly mixed. Furthermore, 0.4 parts of zinc octylate was added as a catalyst, dissolved and mixed, and to this was added 500 parts of inorganic insulating filler (trade name: BST200, average particle size 0.4 μm, manufactured by Nippon Talc Co., Ltd.), epoxy silane cup. A varnish A was obtained by adding 4 parts of a ring agent and 2 parts of a black pigment and stirring and mixing them uniformly. This varnish is 100 μm thick
This was impregnated with the glass woven fabric of Example 1 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 57% by weight. Electrolytic copper foil with a thickness of 12 μm is placed above and below the above four prepreg B sheets,
Laminate molding was carried out for 2 hours under vacuum at 20 ° C., 20 kgf / cm ² , 30 mmHg or less to obtain a double-sided copper-clad laminate C having an insulating layer thickness of 400 μm. On the other hand, 800 parts of black copper oxide powder having an average particle diameter of 0.9 μm was added to a varnish prepared by dissolving polyvinyl alcohol powder (melting point 83 ° C.) in water, and uniformly mixed with stirring. This is coated on a polyethylene terephthalate film having a thickness of 25 μm with a thickness of 20 μm and dried at 110 ° C. for 30 minutes to obtain a metal oxide content of 13 vol.
% Sheet with film (auxiliary material D) was formed. Place this on the double-sided copper-clad laminate C, stack 3 sets, and apply 900 pulses directly to the carbon dioxide laser with 300 μm intervals and 100 μm hole diameters, and apply 19 pulses (shots) at an output of 40 mJ / pulse. , 70 blocks through holes for through holes were opened. After peeling and removing the auxiliary material D on the surface, SUE
At the same time by removing the copper foil burr around the hole by P method,
The copper foil on the surface also dissolved to 5 μm. Copper plating of 15 μm (total thickness: 20 μm) was applied to this plate by a conventional method. All the copper foil for land around this hole remained. A circuit (line / space = 50/50 μm 200
Individual), solder ball lands, etc. are formed, and at least semiconductor chips, bonding pads, and solder ball pads are covered with a plating resist, and nickel and gold are plated to form a printed wiring board. Table 1 shows the evaluation results of this printed wiring board.

Example 2 1400 parts of epoxy resin (trade name: Epikote 5045), 600 parts of epoxy resin (trade name: ESCN220F), 70 parts of dicyandiamide, 2 parts of 2-ethyl-4-methylimidazole are mixed with methyl ethyl ketone and dimethylformamide. After dissolving in a solvent, 800 parts of the insulating inorganic filler of Example 1 was added, and the mixture was forcibly stirred and uniformly dispersed to obtain a varnish. This is impregnated in 100 μm thick glass woven cloth, dried and gelled.
A prepreg (prepreg E) having a glass cloth content of 55 wt% was prepared for 150 seconds. Use one piece of this prepreg E, put electrolytic copper foil of 12μm on both sides, and 190 ℃, 20kgf / cm ² , 30m
Double-sided copper-clad laminate F was prepared by laminate molding for 2 hours under a vacuum of mHg or less. The insulating layer had a thickness of 100 μm. On the other hand, the average particle size consisting of 43% MgO and 7% Sio2 above
0.8 μm of a metal oxide was dissolved in a polyvinyl alcohol solution, and this was applied to a 25 μm-thick polyethylene terephthalate film so as to have a thickness of 25 μm and dried in the same manner as in Example 1 to obtain 90 volume of the metal oxide. %, A sheet having a resin composition layer attached thereto was prepared. This is placed on the double-sided copper clad laminate F and laminated in the same manner as in Example 1,
8 sets of this are piled up, and carbon dioxide laser output is 40 mJ /
A through hole for a through hole was opened with 25 pulses (shots). After that, the same processing was performed to prepare a printed wiring board. The evaluation results are shown in Table 1.

Comparative Example 1 The double-sided copper-clad laminate of Example 1 was used to carry out the same drilling with a carbon dioxide laser without disposing an auxiliary material on the surface, but no holes were found.

Comparative Example 2 In Example 2, as the epoxy resin, Epicoat 5045 was used.
Using 2,000 parts of each, using the other double-sided copper clad laminates made in the same way, place sheets on the copper foil surface in the same manner, stack 8 sets of this, and use a carbon dioxide laser with an output of 17 mJ / pulse. Shot irradiation was performed to form through holes for through holes. In this hole wall, glass fibers were found in the hole, and the hole shape was not a perfect circle but an elliptical shape. Similarly, the printed wiring board was prepared by washing with warm water, without performing the SUEP treatment, and only by mechanical polishing. The evaluation results are shown in Table 1.

Comparative Example 3 Using one double-sided copper-clad laminate of Example 1, a mechanical drill with a diameter of 100 μm was used to rotate at a speed of 100,000 rpm and a feed rate of 1
Similarly, holes were made at 300 μm intervals at m / min. Mechanical polishing is performed and copper plating is performed in the same manner without performing SUEP treatment.
μm, circuits were formed on the front and back, and processed in the same manner to prepare a printed wiring board. Two drill breaks occurred on the way. The evaluation results are shown in Table 1.

Comparative Example 4 900 holes each having a hole diameter of 100 μm were formed on the copper foil surface of the double-sided copper-clad laminate of Example 1 at intervals of 300 μm by etching the copper foil. Similarly, on the back side, make a hole with a hole diameter of 100 μm at the same position
900 holes, 1 block 900 blocks, 70 blocks, 63,0 in total
Three sets of copper-clad laminates with holes of 00 were stacked, and carbon dioxide gas laser was applied from the surface for 19 pulses (shot) at an output of 40 mJ / pulse to form through holes for through holes. Then, in the same manner as in Comparative Example 3, the copper plating was 15 μm only by mechanical polishing.
Then, a circuit was formed on the front and back, and a printed wiring board was similarly prepared. The evaluation results are shown in Table 1.

<Measurement method> 1) Deviation of front and back hole positions and drilling time A hole with a hole diameter of 100 μm and
70 blocks (63,000 holes in total) were created as holes / blocks. The time required to drill 63,000 holes / sheet and the maximum deviation of the front and back hole positions when the holes were drilled with a carbon dioxide laser and a mechanical drill were shown. 2) Broken circuit pattern and short circuit In the examples and comparative examples, a plate without holes was similarly prepared, and a comb-shaped pattern of line / space = 50/50 μm was prepared, and then 200 patterns after etching with a magnifying glass. Was visually observed, and the total number of pattern breaks and short patterns was shown in the molecule. 3) Glass transition temperature It was measured by the DMA method. 4) Through-hole / heat cycle test A land diameter of 200 μm was created in each through-hole, 900 holes were connected alternately on the front and back sides, and 1 cycle was performed at 260 ° C / solder / immersion 30 seconds → room temperature / 5 minutes, and 200 cycles were performed. The maximum rate of change in resistance was shown. 5) Hole shape The cross section of the hole and the shape from above were observed. 6) A copper foil missing diameter around the land was created to have a diameter of 200 μm, and the copper foil missing state between the land portion of the hole and the through hole was observed.

Table 1 Item Example Comparative Example 1 2 2 3 4 Deviation of front and back hole positions (μm) 0 0 0 0 25 Hole shape Circular circle Elliptical circle Upper circular lower elliptical hole Inside almost straight line Almost straight line Inner wall concave straight line Nearly Straight Convex Large hole size Top, bottom, top, bottom When going to the bottom, the top and bottom plates are almost the same Approximately the same Approximately the same stepwise smaller Same as going to the bottom plate The hole diameter becomes smaller and the copper foil around the land becomes missing No No No No No Yes Pattern breaks and shorts (number) 0/200 0/200 55/200 55/200 57/100 Glass transition temperature (℃) 235 160 139 234 235 Through hole heat cycle test (%) 2.6 4.3 27.8 2.6 10.9 Drilling time (min) 17 10 16 630 −

[0036]

EFFECTS OF THE INVENTION Using a ta energy selected from a high output of 20 to 60 mJ / pulse which is sufficient to remove a copper foil with a carbon dioxide gas laser, a pulse oscillation of a carbon dioxide gas laser penetrates a large number of copper clad plates. A method of forming pores, preferably a glass cloth as a base material, which is blackened by mixing an insulating dye or pigment with a thermosetting resin having a glass transition temperature of 150 ° C or higher, and an insulating inorganic filler. And a glass foil base copper-clad laminate in which the ratio of the inorganic filler and the resin in the thermosetting resin composition is uniform in the cross section of the laminate, and the copper foil is irradiated with a carbon dioxide laser. On the surface, metal compound powder,
Arrange a coating film or sheet of an organic material containing one or more of carbon powder or metal powder, and apply 2 to 2 in total.
By stacking 10 sheets and irradiating with energy selected from a carbon dioxide gas laser of 20 to 60 mJ / pulse to form through holes, there is no deviation in the hole positions on the front and back, and the hole walls are well opened. It was possible to obtain a through hole with excellent connection reliability. In addition, the processing speed is much faster than drilling, and the productivity can be greatly improved.

[Brief description of drawings]

FIG. 1 is a process drawing of through hole drilling [(1), (2)] using a carbon dioxide laser, burring removal [(3)] by SUEP, and copper plating [(4)] in Example 1.

FIG. 2 is a similar process drawing of a carbon dioxide gas laser of Comparative Example 4. However, do not use SUEP.

[Explanation of symbols]

a metal oxide powder-containing resin sheet b copper foil c glass cloth base thermosetting resin layer d through hole through hole punched by carbon dioxide laser e burr f generated through hole through hole through hole through which copper foil shift occurred g Copper plated misalignment through hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuo Tanaka             6-1, 1-1 Shinjuku, Katsushika-ku, Tokyo Mitsubishi tile             The chemical company Tokyo factory F-term (reference) 4E068 AA04 AF01 CA01 CA03 DA11                       DA14 DB02 DB07

Claims (2)

[Claims] 1. A copper having at least two copper layers by pulse oscillation of a carbon dioxide laser using energy selected from 20 to 60 mJ / pulse sufficient to remove the copper foil with the carbon dioxide laser. In the method of simultaneously forming a plurality of through-holes in a stretched plate, at least on a copper foil surface irradiated with a carbon dioxide gas laser, a metal compound powder having a melting point of 900 ° C. or more and a binding energy of 300 KJ / mol or more, carbon powder, or metal powder One or more kinds of organic coating films or sheets containing 3 to 97 vol% of the above are arranged, and 2 to 10 of these are stacked and radiated with a carbon dioxide laser pulse for a required number of pulses to simultaneously form a large number of copper clad boards. A method of forming a hole, which comprises forming a through hole. 2. Both surfaces of the perforated copper clad plate are planarly etched to partially etch the original copper foil, and at the same time copper foil burrs overhanging the holes are etched. The method for forming a hole according to claim 1, wherein the hole is removed.