JP2003069218A - Method for manufacturing printed wiring board having extra-fine pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high density printed wiring board having an excellent copper foil adhesive force and an extra-fine pattern having a good shape. SOLUTION: A method for manufacturing the printed wiring board comprises the steps of removing the copper foil of a copper-clad board by etching to retain its surface ruggedness, forming through holes and/or blind via holes through the board, surface-treating the board, then to a surface ruggedness to 1 to 7 μm, electroless copper plating thereon in thickness of 0.1 to 2 μm, then electrically copper plating to 0.5 to 3 μm, adhering a plating resist, then adhering an electric copper plating to 6 to 30 μm, releasing the plating resist, and removing a thin electric copper plating layer and an electroless copper plating layer by dissolving, and thereby forming a pattern of line/space=40/40 μm or less and further 25/25 μm or less. Accordingly, a copper pattern undercut is extremely small, and the high density printed wiring board having the excellent adhesive force of the copper can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a printed wiring board having a fine line pattern having a line / space of, for example, 40/40 μm or less, further 25/25 μm or less. High density printed wiring boards having line patterns are mainly used for new semiconductor plastic packages and the like.

[0002]

2. Description of the Related Art Conventionally, in a high-density printed wiring board used for semiconductor plastic packages and the like, a method of forming a fine line pattern is a subtractive method of 5 μm.
Using the following ultra-thin copper foil, after forming through-holes and / or blind via holes with carbon dioxide laser etc., then copper plating
Deposit about 15 μm and remove the copper foil by etching using a plating resist or directly irradiate carbon dioxide gas laser on the copper foil to remove copper foil burr generated in the hole after forming the through hole and / or blind via hole. 12μ the surface layer of the copper foil and simultaneously dissolved and removed by SUEP (S urface U niform E tching P rocess)
There is known a method of dissolving and removing from the thickness of m to 5 μm or less, performing desmear treatment, depositing copper plating to a thickness of about 15 μm, and forming an ultrafine wire pattern using a normal etching resist or the like. In these methods, the upper side of the pattern becomes thinner than the bottom side due to etching, and the cross section becomes trapezoidal or triangular, causing defects.

There is also a method of forming an ultrafine wire pattern by using an etching resist or the like in the same manner after plating up by the semi-additive method, but this is also done when the thickness of copper plating is increased to about 18 μm. The shape was similar, and there was a problem with the adhesive strength to copper. Further, when the copper plating is attached by the full additive method, there are problems such as low adhesion with copper and low reliability. On the other hand, using an ultra-thin copper foil, after applying electroless copper plating on this, a method of forming a pattern by the pattern copper plating method, and further a thin electroless copper layer on the substrate by the semi-additive method There is a method of forming a pattern by a pattern copper plating method using
In the final flash etching, the electroless copper layer was side-etched, and there was a problem with copper adhesion in a fine pattern. Further, in a fine pattern, reliability such as migration resistance has been a problem.

[0004]

DISCLOSURE OF THE INVENTION The present invention has solved the above problems and formed an ultrafine wire pattern which retains the adhesive strength of a copper foil and has a good shape, and has high reliability such as migration resistance. An excellent method for manufacturing a high-density printed wiring board is provided.

[0005]

The present invention provides a high-density printed wiring board having an ultrafine wire pattern and excellent adhesive strength of copper foil by manufacturing the printed wiring board in the following steps. I was able to get it. That is, (1) the entire surface of the metal foil of the double-sided metal foil-clad plate of at least two layers is removed by etching, leaving (2) through holes and / or blind via holes at predetermined positions. Then, (3) the whole is processed so that the unevenness of the surface layer becomes 1 to 7 μm,
(4) 0.1 ~ 2 μm electroless copper plating is applied to the whole plate,
(5) 0.5 ~ 3μm thickness using the electroless copper plating deposition layer as an electrode
Forming an electrolytic copper plating layer, (6) forming a plating resist layer for pattern electroplating on a necessary portion on the copper plating deposit layer, and (7) on the copper surface on which the plating resist layer is not formed, Electrolytic copper plating pattern copper plating 6 ~ 30μm,
It is preferably 10 to 20 μm deposited, (8) the plating resist is peeled off, and (9) the entire surface is etched to form a thin electrolytic copper layer and an electroless copper layer at least where the pattern copper plating layer is not formed. It is removed by dissolution to produce a printed wiring board having an ultrafine wire pattern.

Further, in order to improve the adhesive strength of the copper foil, the double-sided metal foil-clad sheet has a resin composition layer containing a rubber having a butadiene skeleton as an essential component on both sides of an inner layer board and having no base material reinforcement. Or a resin composition layer containing a resin powder that dissolves in the treatment (3) of claim 1 is formed on at least the surface layer of the double-sided copper-clad plate, and the surface treatment such as desmear treatment is performed. By setting the surface unevenness to be 1 to 7 μm, preferably 2 to 5 μm, the printed wiring having an ultrafine wire pattern with excellent adhesive strength with the subsequent electroless copper plating copper and the pattern shape is also excellent. The board was manufactured.

Further, as the resin component of the thermosetting resin composition, by using a polyfunctional cyanate ester and a cyanate ester prepolymer as an essential component in at least the surface layer of the double-sided metal foil-clad sheet, It was possible to obtain a high-density printed wiring board having excellent reliability such as migration resistance.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention uses a double-sided metal foil-clad sheet laminated using a metal foil having irregularities on a general mat surface, line / space = 40/40 μm, and further 25/25 μm or less. To manufacture a high-density printed wiring board having a fine wire pattern. The steps are: (1) First, a metal-clad sheet having irregularities on a general matte surface, preferably an electrolytic copper foil, is provided on the outermost layer to prepare a copper-clad plate having at least two copper layers. The entire surface of the copper foil of this double-sided copper clad plate is completely removed by etching to leave the surface irregularities. As the copper foil, generally known copper foil can be used. It is preferable that the unevenness of the matte surface is large. The thickness of the copper foil is not particularly limited, but is preferably 18 to 50 μm. When the thickness of the copper foil is less than 18 μm, the unevenness after etching is small, which may cause a problem that the adhesive strength of the copper foil becomes low in the subsequent steps. If the copper foil is thicker than 50 μm, it takes time to etch the copper foil, resulting in poor productivity. In addition, a known metal foil such as nickel foil is used.

(2) Next, a through hole and / or a blind via hole is formed at a predetermined position. For the through hole and / or the blind via hole, when the hole diameter is 25 μm or more and less than 80 mμm, a UV laser such as a YAG laser or an excimer laser is used.
When the pore size is 80 μm or more and 180 mμm or less, carbon dioxide laser is preferable. The carbon dioxide gas laser is irradiated with pulse oscillation, preferably with a pulse energy of 5 to 30 mJ, to form a through hole and / or a blind via hole of a predetermined size at a predetermined position. When a blind via hole is formed, a resin residue of about 1 μm remains at the bottom of the hole, so it is necessary to perform resin removal treatment such as desmear treatment or plasma treatment before electroless copper plating. Carbon dioxide laser is in the infrared wavelength range 9.3 to 1
A wavelength of 0.6 μm is commonly used. Also, through holes with a hole diameter of more than 180 μm are drilled with a mechanical drill. Of course, it is also possible to make a hole with the copper foil still attached and then etch the copper foil.

(3) The entire etched plate is processed so that the unevenness of the surface layer is 1 to 7 μm, preferably 2 to 5 μm. The method of treating the plate is not particularly limited, and it is set to such an extent that the unevenness after etching the copper foil is not significantly impaired. Specific examples of the treatment method include desmear treatment with a solution of potassium permanganate or the like, plasma treatment, and the like.

(4) 0.1-2 μm electroless copper plating is applied to the entire plate. When the plating thickness is large, undercut occurs in the lower part of the pattern due to flash etching (etching in (9) below), and the copper foil adhesive strength is reduced, causing defects.

(5) Next, an electroless copper plating layer having a thickness of 0.5 to 3 μm is formed by using the electroless copper plating deposition layer as an electrode.
The type of copper plating is not particularly limited, and for example, copper sulfate plating, copper pyrophosphate plating, etc. can be used. (6) A plating resist layer for pattern electroplating is formed on a necessary portion on the copper plating deposit layer. This step is also performed by a generally known method. (7) On the copper surface on which the plating resist layer is not formed, apply a pattern copper plating of 6 to 30 μm by electrolytic copper plating, (8) remove the plating resist, and (9) etch the entire surface to remove at least the pattern. The thin electrolytic copper layer and the electroless copper layer in the portion where the copper plating layer is not formed are dissolved and removed until reaching the base material to manufacture a printed wiring board having an ultrafine wire pattern. By producing a fine pattern in this step, an undercut was not generated as compared with a usual method, a pattern with a good shape could be formed, and a highly reliable printed wiring board could be manufactured.

After the entire surface is electrolytically copper-plated lastly, the plating resist is peeled off, and the thin copper layer portion is etched until it reaches the substrate to form a pattern. This etching solution is not particularly limited, for example, JP-A-02-22887,
02-22896, 02-25089, 02-25090, 02-59337,
02-60189, 02-166789, 03-25995, 03-60183, 0
3-94491, 04-199592 and 04-263488, a method of dissolving and removing a metal surface with a chemical (referred to as a SUEP method), a method of using ferric chloride, copper chloride or ammonium persulfate solution. Generally known methods such as the above can be used, but the SUEP method is preferably used. The etching rate is not particularly limited, but is generally 0.02 to 1.0 μm / sec.

The thermosetting resin composition used for the double-sided copper clad board of the present invention is not particularly limited, and generally known thermosetting resins are used. Specifically, epoxy resin, polyfunctional cyanate ester resin polyfunctional maleimide-cyanate ester resin, polyfunctional maleimide resin, unsaturated group-containing polyphenylene ether resin, and the like, one or more kinds. Used in combination. A polyfunctional cyanate ester resin composition is preferable in terms of heat resistance, migration resistance, electrical characteristics after moisture absorption, and the like.

The polyfunctional cyanate ester compound preferably used in the present invention is a compound having two or more cyanato groups in the molecule. Specifically, 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
Examples include (4-cyanatophenyl) phosphate, and cyanates obtained by the reaction of novolac and cyanogen halide. Those in which bromine is bound in these molecules can also be used.

[0016] In addition to these, Japanese Patent Publications 41-1928 and 43-1846
8, polyfunctional cyanate ester compounds described in JP-A-51-63149 and JP-A-44-4791, JP-A-45-11712, JP-A-46-41112 and JP-A-47-26853 can also be used. Further, a prepolymer having a molecular weight of 400 to 6,000 and having a triazine ring formed by trimerizing the cyanato group of these polyfunctional cyanate ester compounds is 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 as a catalyst. 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.

The epoxy resin may be either solid or liquid at room temperature. As the epoxy resin which is liquid at room temperature, generally known bromine-bonded ones and bromine-unbonded ones can be used. Specifically, bisphenol A type epoxy resin, bisphenol F
Type epoxy resins, phenol novolac type epoxy resins, diglycidylated products of polyether polyols, epoxidized products of acid anhydrides, alicyclic epoxy resins and the like are used alone or in combination of two or more. In addition, as the solid resin, generally known resins such as the solid resins of the above resins can be used.

In addition to the thermosetting resins described above, a polyimide resin, a polyphenylene oxide resin having a double bond in the molecule, and the like are used alone or in combination of two or more. In the double-sided copper-clad board, to form a resin composition layer with or without base material reinforcement containing a rubber component having a butadiene skeleton as an essential component in the entire thermosetting resin or surface layer,
It is preferable to increase the adhesive strength of copper plating.

The resin having a butadiene skeleton of the present invention in the molecule is not particularly limited, but specifically, epoxy group-containing polybutadiene resin, polybutadiene resin, MBS resin,
Examples thereof include ABS resin, butadiene-acrylonitrile resin, butadiene-styrene resin, and maleated butadiene resin. These are used by a method of blending in powder, a method of being compatible with a resin and uniformly dispersing. These components are used alone or in combination of two or more.

Further, by forming a resin composition layer containing a resin powder which is dissolved in the step of treating the etched plate on at least the surface layer of the double-sided copper clad plate, this portion is selectively dissolved and removed. As a result, irregularities can be formed, and the adhesiveness of copper plating can be improved. This powder is not particularly limited, and specifically, known powders of thermosetting resin and thermoplastic resin can be used, and the particle diameter is generally 0.5 to 5 μm.
Use m. Further, a resin having a butadiene skeleton compatible with the resin composition can be blended.

The copper-clad board used in the present invention is a copper-clad board having two or more layers of copper. The thermosetting resin copper-clad laminate is a known thermosetting resin for inorganic and organic base materials. Copper clad laminate,
Examples thereof include a multilayer copper clad board, a multilayer board using a resin-coated copper foil sheet as a surface layer, and the like, and a copper clad board as a base material such as a polyimide film and a polyparabanic acid film.

The base material-reinforced copper-clad laminate is prepared by first impregnating the reinforcing base material with the thermosetting resin composition and drying it to form B stage,
Create a prepreg. Next, a predetermined number of these prepregs are stacked, a copper foil having irregularities formed on the matt surface is arranged on the outside thereof, and laminated under heat and pressure to form a copper clad laminate. The multilayer board, the copper foil of this double-sided copper clad laminate is processed to form a pattern, and the copper foil surface is processed to produce an inner layer board,
A prepreg, a B-stage resin sheet, etc. are placed on the outside of this, and a copper foil is placed on the outside and laminated, or a B-stage resin sheet with a copper foil is placed on the outside of the inner layer plate and laminated to form a multilayer. Use copper clad board. Since this copper foil is removed by etching, another metal foil having unevenness on the matte surface may be used.

As the substrate, generally known organic and inorganic woven fabrics and nonwoven fabrics can be used. Specifically, examples of the inorganic fiber include fibers such as E, S, D, and NE glass. Examples of the organic fiber include generally known fibers such as wholly aromatic polyamide and liquid crystal polyester. These may be mixed papers. Moreover, a film base material can also be used.

[0024]

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, bis (4-
Maleimide phenyl) 100 parts of methane is melted to 150 ℃,
The reaction was carried out for 4 hours with stirring to obtain a prepolymer. This was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide. In addition to this, bisphenol A type epoxy resin (trade name: Epicoat 1001, Yuka Shell Epoxy Co., Ltd.)
400 parts of cresol novolac type epoxy resin (trade name: ESCN-220F, manufactured by Sumitomo Chemical Co., Ltd.) were added and uniformly mixed. Furthermore, MBS resin (trade name: Paraloid E
XL-2655, Kureha Chemical Co., Ltd. 200 parts, epoxidized polybutadiene resin (Denalex R-45EPT, Nagase Chemtex)
100 parts of Co., Ltd.) and 0.4 part of zinc octylate as a catalyst were added and uniformly dissolved and mixed, and 2000 parts of an inorganic filler (trade name: calcined talc, manufactured by Nippon Talc Co., Ltd.) was added and uniformly mixed. Varnish A was obtained by mixing with stirring. This varnish was impregnated into a glass woven cloth with a thickness of 100 μm, dried at 150 ° C, and the gelation time (at
A prepreg (prepreg B) having a thermosetting resin composition content of 44% by weight was produced at 170 ° C. for 120 seconds. Electrolytic copper foil with a thickness of 18 μm (surface roughness Kz = 2.6 μm) is placed above and below four of the above prepregs B, and the temperature is 200 ° C, 20 kgf / cm ² , under vacuum of 30 mmHg or less.
Laminate molding was performed for 2 hours to obtain a double-sided copper-clad laminate C having an insulating layer thickness of 400 μm.

The copper foils on both sides of this copper clad laminate were removed by etching. The surface roughness was 3.6 to 4.5 μm on average.
From the surface of this plate, 6 shots were irradiated with a pulse energy of a carbon dioxide laser of 15 mJ to form a through hole having a hole diameter of 100 μm. After performing desmear treatment to dissolve the butadiene rubber component on the surface layer to make unevenness 4.2 to 5.0 μm, electroless copper plating is attached to a thickness of 0.9 μm, and then electrolytic copper plating is applied to a thickness of 1.7 μm.
A μm copper layer was deposited. A 15 μm thick resist layer for patterned copper electroplating on the required area on this copper plating deposit layer.
After forming m, pattern copper plating is attached by 15 μm by electrolytic copper plating on the copper surface where the plating resist is not formed, and after removing the plating resist, the entire surface is etched with SUEP solution, line / space = 25/25 μm Pattern was formed. The cross section of this pattern had a good shape without undercutting due to etching. A plating resist was deposited on this, and nickel plating and gold plating were deposited. Table 1 shows the evaluation results of this printed wiring board.

Example 2 700 parts of epoxy resin (trade name: Epicoat 5045), 300 parts of epoxy resin (trade name: ESCN220F), dicyandiamide 35
Parts, 1 part of 2-ethyl-4-methylimidazole was dissolved in a mixed solvent of methyl ethyl ketone and dimethylformamide, 800 parts of the calcined talc of Example 1 was further added, and the mixture was forcibly stirred and uniformly dispersed to obtain a varnish D. . This is impregnated into a glass woven fabric having a thickness of 100 μm and dried, and a gelling time of 150 seconds, a prepreg having a thermosetting resin composition content of 45% by weight (prepreg E)
Was produced. Also, for 100 parts of the above varnish D, acrylonitrile / butadiene rubber (trade name: XER-91, Japan Synthetic Rubber <
Co., Ltd.) was mixed and uniformly dispersed in 10 parts, and the thickness was 50
Impregnated into a glass woven cloth of μm, dried, gel time 178 seconds,
A prepreg (prepreg F) having a thermosetting resin composition content of 70% by weight was prepared. Two pieces of this prepreg E are used, a general electrolytic copper foil with a thickness of 12 μm is placed on both sides, 190 ° C, 20 kgf /
Double-sided copper-clad laminate G was produced by laminating and molding for 2 hours under a vacuum of cm ² and 30 mmHg or less. Patterns are formed on both sides, black copper oxide treatment is applied, one piece of the above prepreg F is arranged on both outer sides, and a general electrolytic copper foil having a thickness of 35 μm is arranged on the outer side, and similarly laminated forming Then, a four-layer board was produced. The copper foil on this surface was removed by etching. Surface unevenness is 4.3 ~
It was 4.8 μm. Carbon dioxide laser pulse energy of 15 mJ was irradiated from this surface for one shot, and blind via holes with a hole diameter of 100 μm were opened on both sides. This was put in a plasma device to remove the residual resin at the bottom, and at the same time, the unevenness of the surface layer was adjusted to 4.6 to 5.5 μm.

After electroless copper plating with a thickness of 1 μm is applied to the whole, and then electrolytic copper plating with a thickness of 2 μm is applied, a plating resist for electrolytic copper plating of 15 μm is adhered, and a plating resist layer is not formed. 14μ electrolytic copper plating on the copper surface
m adhere, peel off the plating resist, and etch the entire surface to dissolve and remove the thin electrolytic copper layer and electroless copper layer in the part where the pattern copper plating layer is not formed, and have line / space = 20 / 20μm A printed wiring board was produced.
A plating resist is attached on this, nickel plating,
Gold plated. The evaluation results are shown in Table 1.

Comparative Example 1 In the production of the printed wiring board of Example 1, only the electroless copper plating was applied to a thickness of 2 μm, and the subsequent electroless copper plating was not applied. Was applied. This was similarly etched, and the thin electroless copper layer to which the pattern copper plating was not attached was removed by etching to obtain a printed wiring board. This had undercuts of 3.7 μm on both sides. After that, a printed wiring board was prepared in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 2 A general electrolytic copper foil having a thickness of 12 μm was applied to the surface layer of the 4-layer copper clad laminate of Example 2, and this was etched to an average thickness of 3 μm, and at the same time unevenness of 1 μm was formed on the surface of the copper foil. Place this on an XY table, irradiate one shot of carbon dioxide laser pulse energy of 14 mJ from the surface to open a blind via hole, and similarly perform plasma treatment, then electroless copper plating to 2 μm
Then, 14 μm of electrolytic copper plating was deposited, and 20 μm of etching resist was deposited thereon, and then a pattern of line / space = 20/20 μm was formed, but the shape was a triangle and the shape was not good. After that, a printed wiring board was prepared in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Table 1) Item Example Comparative Example 1 2 1 2 Undercut (μm) <1 <1 3.7 <1 Pattern cross-sectional shape Good Good Somewhat poor Triangle copper foil adhesion (kgf / cm) 1.06 1.09 0.70 0.87 The glass transition temperature <layer resin> (℃) 196 153 195 153 migration resistance normal ^{4x10 14 5x10 14 5x10 14 6x10 14} 200hrs. 7x10 10 7x10 8 6x10 10 7x10 8

<Measurement method> 1) Undercut and pattern cross-section shape: 100 pattern cross-sections were observed and displayed as an average value. For design value,
The etched distance on one side is shown. The shape was also observed. 2) Copper foil adhesion: Measured according to JIS C6481. The width was measured by the pattern width and converted into kgf / cm for display. 3) Glass transition temperature: measured according to the DMA method of JIS C6481. 4) Migration resistance: In each of the examples and comparative examples, a thermosetting resist (product name:
BT-M450 Mitsubishi Gas Chemical Co., Ltd.) was coated to a thickness of 40 μm and cured, and this was applied at 85 ° C., 85% RH, 50 VDC, and the insulation resistance value between patterns was measured.

[0032]

INDUSTRIAL APPLICABILITY In a method for producing an ultrafine wire pattern on a copper clad plate having at least two copper layers having through holes and / or blind via holes, surface irregularities are removed by etching the surface copper foil. After forming through holes and / or blind via holes, the surface is processed to have surface irregularities of 1 to 7 μm, preferably 2 to 5 μm, and electroless copper plating of 0.1 to 2 μm is deposited on this. And 0.5 to 3 μm of electrolytic copper plating, and then depositing a plating resist to perform pattern copper plating of 6 to 30 μm.After removing the plating resist, etching the thin electrolytic copper layer and electroless copper layer until reaching the substrate. By removing it, it was possible to fabricate a pattern having a very small undercut, an excellent copper adhesive force, and a good shape.

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Claims (4)

[Claims] (1) (2) Through holes and / or blind via holes are provided at predetermined positions while the entire metal foil of the double-sided metal foil-clad sheet of at least two layers is removed by etching to leave the surface unevenness. After making holes in (3), the whole surface is processed so that the unevenness of the surface layer becomes 1 to 7 μm, and (4) 0.1 to 2 is applied to the whole plate.
Applying electroless copper plating of μm, (5) forming an electroless copper plating layer having a thickness of 0.5 to 3 μm by using the electroless copper plating deposit layer as an electrode, (6) necessary portion on the copper plating deposit layer Form a plating resist layer for pattern electroplating on (7) Apply 6 to 30 μm of pattern copper plating by electro copper plating on the copper surface where the plating resist layer is not formed, and (8) remove the plating resist. Then, (9) by etching the entire surface, at least the thin copper copper layer of the portion where the pattern copper plating layer is not formed, the electroless copper layer and the ultra-thin copper foil layer are dissolved and removed to produce. A method for manufacturing a printed wiring board having an ultrafine wire pattern. 2. The printed wiring board having an ultrafine wire pattern according to claim 1, wherein the double-sided metal foil-clad board has a resin composition layer containing a rubber having a butadiene skeleton as an essential component on both surfaces of an inner layer board. Production method. 3. At least the surface layer of the double-sided metal foil-clad plate,
The method for producing a printed wiring board having an ultrafine wire pattern according to claim 1, wherein a resin composition layer containing a resin powder that dissolves in the treatment (3) of claim 1 is formed. 4. The thermosetting resin used for at least the surface layer of the double-sided metal foil-clad sheet contains a polyfunctional cyanate ester and the cyanate ester prepolymer as essential components. A method for manufacturing a printed wiring board having an ultrafine wire pattern.