JP2003243808A - Method of manufacturing printed wiring board equipped with very fine wire pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-density printed wiring board equipped with a very fine wire pattern that is excellent in adhesion to a copper foil and superior in shape. <P>SOLUTION: A layer made of nickel and/or cobalt or an alloy of them is formed as thick as 0.1 to 3 μm on one surface of a carrier sheet, and a rugged layer made of nickel and/or cobalt or an alloy of them is formed as thick as 0.5 to 5 μm on the above layer for the formation of a metal foil with the carrier sheet. A double-sided copper plated board or a multilayer double-sided copper plated board is formed, using the above metal foil with the carrier sheet as its outermost layer, the carrier sheet is removed from the double-sided copper plated board or the multilayer double-sided copper plated board, a thin electroless plating copper layer and an electrolytic copper layer are provided to the residual layer of nickel metal, cobalt metal or an alloy layer of them, then a pattern plating resist layer is deposited thereon, a pattern electrolytic copper plating process is carried out, the plating resist layer is removed, the thin electroless plating copper layer and the electrolytic copper layer are selectively removed by dissolution, and then the layer of nickel metal, cobalt or an alloy of them is selectively removed by etching for the formation of the high-density printed wiring board. Therefore, the high-density wiring board which is equipped with the very fine wire pattern having almost no undercut and excellent in adhesion to the copper foil can be obtained. <P>COPYRIGHT: (C)2003,JPO

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. At the same time as melting and removing, the surface copper foil is 12μ by SUEP (Surface Uniform Etching Process)
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 this method, the pattern becomes thinner than the bottom by etching, and the cross section becomes trapezoidal or triangular, which causes the occurrence of 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. Same shape, 1
When the thickness is reduced to about 0 μm, there is a defect that the adhesion thickness of the hole is insufficient and the reliability is poor, and there is a problem in the adhesive force with copper.
Further, when the copper plating adheres by the full additive method, there is a problem that the copper foil adhesion is low even if the copper foil is thickened. 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 this, but the electroless copper layer was side-etched by the final flash etching, and there was a problem in copper adhesion.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems by using a subtractive method, and holds the adhesive force of a copper foil and forms a fine line pattern having a good pattern shape. A method for manufacturing a 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) nickel and / or cobalt, or an alloy layer thereof having a thickness of 0.1 to 3 μm is formed on one surface of the carrier sheet, and nickel and / or cobalt or an alloy layer thereof has a thickness of 0.5 to 5 μm. After removing the carrier sheet of the surface layer of the double-sided copper-clad plate or the multilayer double-sided copper-clad plate prepared by using the metal foil with a carrier sheet obtained by forming irregularities as at least the outermost layer, (2) on the surface including the hole 0.1 to 1 μm electroless copper plating is performed, (3) the electroless copper plating deposit layer is used as an electrode to form an electro copper plating layer having a thickness of 0.5 to 3 μm, and (4) on this copper plating deposit layer. Form a plating resist layer for pattern electroplating on the required part, and (5) attach a pattern copper plating of 6 to 30 μm by electrocopper plating to the copper surface where the plating resist layer is not formed. Strip and remove (7) at least patterned copper plating layer shape After etching the entire surface of the thin electrolytic copper layer and the electroless copper layer which are not formed with a chemical solution that hardly dissolves nickel or cobalt, or its alloy layer, leaving nickel or cobalt, or its alloy layer,
(8) By etching the whole with a chemical solution that hardly dissolves copper and removing nickel or cobalt or its alloy layer to form an ultrafine wire pattern, it is an ultrafine wire, has a good shape, and has excellent adhesive strength. It was possible to manufacture printed wiring boards.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is to form a nickel and / or cobalt or alloy layer thereof having a thickness of 0.1 to 3 μm on one surface of a carrier sheet, and further form a nickel and / or cobalt or alloy layer thereof thereon. Nickel and / or by removing the carrier sheet of the surface layer of a double-sided copper-clad plate or a multilayer double-sided copper-clad plate prepared by using a metal foil with a carrier sheet obtained by forming irregularities having a thickness of 0.5 to 5 μm as at least the outermost layer Or, cobalt or its alloy layer is left, and using this, line / space = 40 / 40μm or less, further 25 / 25μm
This is a method for producing a high-density printed wiring board having the following fine line pattern. The process is as follows: (1) First, a nickel and / or cobalt or alloy layer thereof is formed to a thickness of 0.1 to 3 μm on one surface of a carrier sheet, and further nickel and / or cobalt or an alloy layer thereof is formed to a thickness of 0.5 to 3 μm. After removing the carrier sheet of the double-sided copper-clad plate or the surface layer of the double-sided copper-clad plate prepared by using the metal foil with a carrier sheet obtained by forming the unevenness of 5 μm as at least the outermost layer, at least an electrolytic copper foil made It is used as the outermost layer to prepare a copper clad plate having at least two layers of copper foil. This copper clad plate is provided with through holes and / or
Alternatively, blind via holes are formed. Of course, you may make holes after removing the carrier sheet on the surface layer,
It is also possible to open a hole with the carrier sheet attached and then peel the carrier sheet.

The carrier sheet is not particularly limited as long as nickel and / or cobalt or an alloy layer thereof can be formed on the carrier sheet, but is preferably copper foil, particularly electrolytic copper foil. First, a thin nickel and / or cobalt or its alloy layer is formed on this carrier sheet. The thickness is not particularly limited, but preferably 0.1 to 3 μm is formed, and then nickel and / or cobalt, or an alloy layer thereof, preferably 0.5 to 5 μm (Rz: 10-point average roughness) The unevenness is formed, and the metal foil with a carrier sheet is arranged in at least the outermost layer, and a known method is used,
For example, a double-sided copper-clad board or a multi-layered double-sided copper-clad board is produced by laminating and molding under heating, pressurizing, and preferably vacuum.

A through hole and / or a blind via hole is formed with a laser, a mechanical drill or the like by peeling the carrier sheet on the surface layer of the double-sided copper-clad plate or the multilayer double-sided copper-clad plate or leaving it as it is. Finally, the carrier sheet is peeled off.

(2) Next, the surface of the double-sided plate having the holes including the inside of the holes is subjected to electroless copper plating of 0.1 to 1 μm. (3) Next, using the electroless copper plating deposition layer as an electrode, a thickness of 0.5
Form ~ 3μm electrolytic copper plating layer. The type of copper plating is not particularly limited, and for example, copper sulfate plating, copper pyrophosphate plating, etc. can be used. (4) A plating resist layer for pattern electric copper plating is formed on a necessary portion on the copper plating deposit layer. This step is also performed by a generally known method.

(5) A pattern copper plating of 6 to 30 μm is deposited on the copper surface on which the plating resist layer is not formed by electrolytic copper plating, (6) the plating resist is peeled off, and (7) at least the pattern copper plating layer After the thin electrolytic copper layer and the electroless copper layer of the portion where is not formed, the entire surface is etched with a chemical solution that hardly dissolves nickel or cobalt, or an alloy layer thereof to leave nickel or cobalt, or an alloy layer thereof, (8) By etching the whole with a chemical solution that hardly dissolves copper and removing nickel or cobalt or its alloy layer to form an ultrafine wire pattern, it is an ultrafine wire, has a good shape, and has excellent adhesive strength. To manufacture printed wiring boards. 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.

As the chemical solution which selectively removes only copper and hardly dissolves nickel metal, cobalt metal or alloys thereof, generally known ones can be used, but alkaline etching having a slow dissolution rate of nickel metal or the like can be used. A liquid is preferably used.

As the chemical liquid having a high etching rate for nickel metal, cobalt metal, or an alloy thereof, and a low etching rate for copper, generally known chemicals can be used.
For example, those mainly containing sulfuric acid / hydrogen peroxide / additive, those mainly containing ammonium fluoride / hydrogen peroxide / additive and the like can be mentioned. Commercially available products include Mitsubishi Gas Chemical Co., Ltd.'s trade name Pyutax, Meltex's Melstrip N-950, and the like.

The copper-clad board used in the present invention is a copper-clad board having two or more copper layers. The thermosetting resin copper-clad laminate is a known thermosetting resin for inorganic and organic base materials. Double-sided copper-clad laminate, its multilayer double-sided copper-clad laminate, a multilayered board using a resin-coated copper foil sheet as the surface layer, etc., a multilayered copper-clad board having a generally known structure, a polyimide film, a polyparabanic acid film, and a wholly aromatic resin. Examples thereof include a copper clad plate as a base material such as a polyamide film and a liquid crystal polyester film.

The base material-reinforced copper-clad laminate is prepared by first impregnating a reinforcing base material with a thermosetting resin composition and drying it to form B stage,
Create a prepreg. Next, a predetermined number of the prepregs are stacked, and a metal foil with a carrier sheet is formed by forming unevenness of nickel and / or cobalt or its alloy on one surface of the carrier sheet as the outermost layer, and the metal foil faces the resin side. As described above, they are placed on both sides and laminated under heat, pressure, and preferably under vacuum to form a double-sided copper clad laminate. The multilayer board is
Form a pattern by processing the copper foil of the double-sided copper clad laminate prepared by using the double-sided plate or known electrolytic copper foil on both sides,
If necessary, chemically process the metal foil surface to produce an inner layer board,
A prepreg, a B-stage resin sheet or the like is placed on the outer side of this, and nickel and / or cobalt with the carrier sheet, or an alloy foil thereof is placed on both sides, and heating, pressing,
Preferably, it is similarly laminated under vacuum, or the B-stage resin sheet is attached to the mat surface of the above-mentioned metal foil with a carrier sheet in which nickel and / or cobalt or its alloy is attached to one side of the carrier sheet. Is placed on both sides of the inner layer board and laminated to form a multilayer copper clad board. A double-sided copper clad multilayer board is produced by a generally known method.

As the substrate, generally known organic and inorganic woven fabrics and nonwoven fabrics can be used. Specific 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, the B stage resin composition sheet of a film base material is also mentioned.

As the resin of the thermosetting resin composition used in the present invention, generally known thermosetting resins are used.
Specifically, epoxy resin, polyfunctional cyanate ester resin, polyfunctional maleimide-cyanate ester resin,
Examples thereof include polyfunctional maleimide resins and unsaturated group-containing polyphenylene ether resins, and they may be used alone or in combination of two or more. From the viewpoint of through-hole shape in processing by high-power carbon dioxide laser irradiation, a thermosetting resin composition having a glass transition temperature of 150 ° C. or higher is preferable,
A polyfunctional cyanate ester resin composition is preferable from the viewpoints of moisture resistance, migration resistance, electrical characteristics after moisture absorption, and the like.

When the through holes and / or the blind via holes are formed by a carbon dioxide gas laser, the method of JP-A-11-220243 and JP-A-11-346059 is used, and black copper oxide treatment, chemical treatment, etc. are performed on the electrolytic copper foil. A method of directly irradiating the copper foil with a carbon dioxide gas laser on the copper foil to form the holes can be used. After that, the electrolytic copper foil on the surface layer is removed by etching, or the electrolytic copper foil is first removed by etching to expose the thin nickel metal, cobalt metal, or alloy treatment layer thereof, and then a carbon dioxide laser is directly applied from above. It is formed by a method of forming holes by irradiation. However, the latter is preferable from the viewpoint of generation of burrs in the holes. Furthermore, UV-Y
Holes can be drilled with an AG laser. A through hole having a diameter of 100 μm or more is generally formed by a mechanical drill by a known method.

The nickel metal, cobalt metal, or an alloy treatment layer thereof used in the present invention is used as a carrier sheet,
As a method for forming on the electrolytic copper foil, a generally known method can be preferably used. Thickness is 0.1-3 μm, preferably 0.5
~ 2 μm. The size of the unevenness formed on this is not particularly limited, but from the viewpoint of forming a fine pattern, preferably the unevenness is 0.5 to 5 μm in average roughness (Rz), more preferably 1 to 4 μm.
Used. The surface of the copper foil of the carrier sheet opposite to the surface on which the nickel metal layer, the cobalt metal layer, or the alloy treatment layer thereof is formed can be treated by a conventionally known method.
For example, there are no surface irregularities, and this surface has been rust-proofed,
A nickel metal, a cobalt metal, or an alloy treatment layer of these metals attached to the surface layer is used.

The carbon dioxide gas laser used for drilling generally has a wavelength of 9.3 to 10.6 μm in the infrared wavelength range. When the copper foil, which is the carrier sheet on the surface layer, is punched after being removed by etching, the copper foil is processed by pulse oscillation at an energy of 5 to 30 mJ, preferably 6 to 20 mJ, and the holes are punched. Energy is surface nickel metal, cobalt metal,
Alternatively, a hole is formed by directly irradiating the alloy-treated layer.

UV such as excimer laser and Nd-YAG laser
Hole formation with a laser can also be used. The UV laser is used to irradiate a laser beam having a UV wavelength to make a hole. The wavelength is not particularly limited, but a wavelength of 200 to 400 nm and a wavelength of 1.06 μm are generally used. Especially solid state UV lasers are used. In this method, the organic substance is processed by a mechanism of breaking the molecular bond constituting the organic substance without giving the influence of heat to the utmost. Carbon is not generated in the holes as compared with the carbon dioxide laser, and the holes are clean, so that the copper plating thereafter can be adhered with high reliability without any special pretreatment. Since the UV laser wavelength is short, it is also absorbed by copper, and by irradiating a laser on the copper foil without using a drilling auxiliary material, it is possible to drill holes in the copper foil and even in the insulating layer. Is.

After electrolytic copper plating on the entire surface lastly, the plating resist for pattern formation is peeled and removed, and the entire surface is etched with an etching solution that hardly dissolves nickel metal, cobalt metal, or an alloy treatment layer thereof to obtain a thin electric layer. After etching away the copper layer and electroless copper layer, change the copper to an etchant that hardly dissolves and etch the nickel metal, cobalt metal, or an alloy treatment layer thereof until reaching the substrate to form a pattern. . This etching liquid is not particularly limited and is appropriately selected.

[0022]

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, zinc octylate 0.4 as a catalyst
2000 parts of an inorganic filler (trade name: calcined talc, manufactured by Nippon Talc Co., Ltd.) was added, and the mixture was stirred and mixed uniformly to obtain a varnish A. This varnish was impregnated into 100 μm thick glass woven cloth, dried at 150 ° C, and the gelation time (at17
(0 ° C) 80 seconds, thermosetting resin composition content of 44% by weight prepreg (prepreg B), and 50 μm thick glass woven cloth impregnated and dried at 150 ° C, gelation time (at 170 ° C) A prepreg C having a thermosetting resin composition content of 70% by weight was produced for 120 seconds. General electrolytic copper foil with a thickness of 18 μm is applied to the above prepreg B
Four sheets were placed on the upper and lower sides, and laminated and formed for 2 hours under a vacuum of 200 ° C., 20 kgf / cm ² , and 30 mmHg or less to obtain a double-sided copper-clad laminate D having an insulating layer thickness of 0.4 mm. After making a pattern on this and applying a black copper oxide treatment, one prepreg C is placed on each of the upper and lower sides, and nickel treatment is applied to the outermost layer of a general electrolytic copper foil with a thickness of 12 μm to 2 μm, and further, A nickel hump (unevenness Rz: 4.2 μm) was placed thereon, and the hump surface was placed so as to face the prepreg side. Then, lamination molding was performed in the same manner to produce a 4-layer double-sided copper-clad laminate E. The 12 μm general electrolytic copper foils on the front and back were removed by etching with an alkaline etching solution to obtain a four-layer double-sided metal-clad laminate F in which only nickel treatment was left.

On the other hand, polyvinyl alcohol powder was dissolved in water to form a resin layer having a thickness of 30 on one side of aluminum having a thickness of 50 μm.
Backup sheet G after coating and drying
Was produced. A backup sheet G was placed under the 4-layer double-sided metal foil-clad laminate F with the resin surface facing the copper foil side, and laminated with a roll at a temperature of 100 ° C. at a linear pressure of 15 kgf / cm. Space 1m from the side opposite to this backup sheet
m through holes with a diameter of 100 μm directly with a carbon dioxide laser,
6 shots were irradiated with a pulse energy of 10 mJ to open a through hole. In addition, a blind via hole having a hole diameter of 100 μm was produced by irradiating 1 shot of 12 mJ. After desmearing, electroless copper plating was applied to this with a thickness of 0.4 μm, and then a copper layer with a thickness of 1 μm was applied with electrolytic copper plating. A resist layer for pattern copper electroplating is formed on the required portion of this copper plating deposit layer to a thickness of 18
Then, a pattern copper plating of 15 μm was deposited by electrolytic copper plating on the copper surface where the plating resist was not formed. A chemical solution that removes all plating resist, etches the entire surface with an alkaline etching solution to remove the thin electrolytic copper layer and electroless copper layer, and then dissolves nickel as a chemical solution (trade name: Pyutax, Mitsubishi Gas Chemical Co., Ltd.)
(Manufactured), and the nickel layer was removed by etching to form a pattern of line / space = 25/25 μm. The cross section of this pattern had a good shape without undercutting due to etching. A UV selective heat-curing permanent protection resist was adhered on this, and nickel plating and gold plating were adhered to obtain a high-density printed wiring board. 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 H. . This is impregnated in 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 I).
It was created. Using 6 sheets of this prepreg I, thickness 12 μm
Nickel-cobalt alloy hump (unevenness Rz: 3.7 μm) is formed on the surface of general electrolytic copper foil (matte surface irregularity Rz: 2.7 μm) with nickel-cobalt alloy treatment of 1.5 μm, and carrier copper Arrange on both sides so that the hump side of the metal foil with foil faces the prepreg side, 190 ℃, 20kgf / cm ² , 30mm
Double-sided copper-clad laminate J after laminated molding under vacuum below Hg for 2 hours
Was produced. After the electrolytic copper foil portion is removed by etching leaving the nickel / cobalt alloy treatment layer on both surfaces, the backup sheet G of Example 1 is arranged on the back surface and similarly laminated and bonded, and a carbon dioxide laser pulse is applied from this surface. Irradiate 8 shots with energy of 10 mJ, pore size 100 μm
A through hole was opened. Put this in a plasma device, after desmearing, apply electroless copper plating with a thickness of 0.3 μm to the whole, then apply electrolytic copper plating with a thickness of 2 μm, and deposit a plating resist for electrolytic copper plating of 15 μm The electrolytic copper plating on the copper surface where the plating resist layer is not formed.
μm was attached. The plating resist was peeled and removed, and the entire surface was flash-etched with an alkaline etching solution to dissolve and remove the thin electrolytic copper layer and the electroless copper layer up to the nickel-cobalt alloy layer. Further, the remaining nickel-cobalt alloy treatment layer was dissolved and removed by the chemical solution for dissolving the nickel-based metal of Example 1 to produce a high-density printed wiring board having a line / space = 20/20 μm. After coating the necessary parts with a UV selective thermosetting permanent protection resist, nickel plating and gold plating were applied to form a printed wiring board. Table 1 shows the evaluation results
Shown in.

Comparative Example 1 In the production of the printed wiring board of Example 1, a surface layer having a thickness of 12
A general electrolytic copper foil with a thickness of μm was applied, and this was etched to an average thickness of 3 μm to form irregularities of 1 μm on the surface. XY this
Place it on a table, irradiate 6 shots of carbon dioxide laser pulse energy of 12 mJ from the surface to open a through hole with 100 μm hole diameter, and irradiate 1 shot of 12 mJ to form a blind via hole with 100 μm hole diameter, then copper plating after desmearing Was electrolessly plated with copper to a thickness of 3 μm, and without subsequent electrolytic copper plating, pattern electrolytic copper plating was directly applied onto the electroless copper plating. This was similarly etched, and the thin electroless copper layer and the ultrathin copper foil layer to which the pattern copper plating did not adhere were removed by etching to obtain a printed wiring board. The underside of this pattern had undercuts of 5.4 μm on both sides. 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 double-sided copper-clad laminate of Example 2, and this was etched to an average thickness of 3 μm to form irregularities of 1 μm on the surface. Place this on an XY table, irradiate 8 shots of carbon dioxide laser pulse energy of 10 mJ from the surface to open a through hole, perform plasma treatment in the same way, apply electroless copper plating to 0.3 μm, and attach electrolytic copper plating to 14 μm Then, an etching resist of 20 μm was deposited on this, and a pattern of line / space = 20/20 μm was formed by a conventional method, but the shape was a triangle and the shape was not good. The evaluation results are shown in Table 1.

Comparative Example 3 After removing the copper foil and the nickel metal layer on the surface of the double-sided copper-clad multilayer board of Example 1 by etching, a through hole having a hole diameter of 100 μm was opened with a carbon dioxide laser of 15 mJ, and the surface was desmeared, Electroless copper plating was applied to a thickness of 2 μm, and electrolytic copper plating was applied thereon to a thickness of 16 μm. In the same manner as in Comparative Example 2, a pattern of line / space = 25/25 μm was formed. This had an undercut, and the shape was a triangle, and the shape was poor. The evaluation results are shown in Table 1.

Comparative Example 4 In Example 2, 100 parts of the solid content of the varnish H was added to acrylonitrile-butadiene rubber (trade name: N210S, JSR <
(Manufactured by K.K.> Co., Ltd.) was added and uniformly mixed with stirring, and then a prepreg was prepared in the same manner and laminated to form a double-sided copper-clad laminate. After removing the copper foil and nickel-cobalt layer on the surface of this copper-clad board by etching, the hole diameter was adjusted with a carbon dioxide laser of 10 mJ.
A 100 μm through-hole is opened, this surface is desmeared, electroless copper plating is applied to the whole surface to 4 μm, and an electrolytic copper plating resist is attached. Electrolytic copper plating is applied on the electroless copper plating where no plating resist is attached. The plating was deposited to 16 μm. After removing the plating resist, the entire surface is etched to dissolve and remove the thin electroless copper plating layer, and the line / space =
A 20/20 μm pattern was formed. This had an undercut. The evaluation results are shown in Table 1.

[0029] (Table 1) Item Example Comparative example  1 2 1 2 3 4 Undercut (μm) <1 <1 5.5 <1 2.2 6.1 Pattern cross-section shape Good Good Bad Triangular triangular Bad Copper foil adhesion (kgf / cm) 1.27 1.10 0.67 0.90 0.43 0.55 Glass transition temperature (℃) 235 160 235 160 235 154 Migration resistance    Normal 6x10¹⁴   4x10¹⁴   5x10¹⁴   4x10¹⁴   5x10¹⁴   5x10 ¹⁴   200hrs. 2x10¹¹   5x10⁸  3x10¹¹   2x10⁸  4x10¹¹   2x10⁸   500hrs. 4x10^Ten   <10⁸   7x10^Ten   <10⁸   5x10^Ten   <10⁸

<Measurement method> 1) Undercut and pattern cross-sectional shape 100 pattern cross-sections were observed and displayed as an average value. The etched distance on one side is shown relative to the design value. or,
The shape was also observed. 2) Copper foil adhesive strength Measured according to JIS C6481. The width was measured by the pattern width and converted into kgf / cm for display. 3) Glass transition temperature It was measured according to the DMA method of JIS C6481. 4) Migration resistance In each of the examples and comparative examples, a thermosetting resist (trade name: BT-M450 manufactured by Mitsubishi Gas Chemical Co., Inc.) is formed on the formed pattern.
To a thickness of 40 μm and cured,
The insulation resistance between the patterns was measured by applying 5 ° C, 85% RH, 50VDC.

[0031]

INDUSTRIAL APPLICABILITY In a method for producing an ultrafine wire pattern on a double-sided copper clad plate having at least two or more thin copper layers having through holes and / or blind via holes, nickel and / or nickel is provided on one surface of a carrier sheet. Cobalt or its alloy layer is formed to a thickness of 0.1 to 3 μm, and further nickel and / or cobalt or its alloy layer is formed to a thickness of 0.5 to 5 μm.
After removing the carrier sheet of the surface layer of the double-sided copper-clad plate or the multilayer double-sided copper-clad plate prepared by using at least the outermost layer of the metal foil with a carrier sheet having irregularities of μm, nickel metal, cobalt metal, or these After applying thin electroless copper plating and electrolytic copper plating on the alloy layer, pattern electroplating resist is attached and pattern electrocopper plating is performed, and after the plating resist is removed, the overall solubility of copper is excellent, nickel metal, cobalt The thin electrolytic copper layer and the electroless copper layer are dissolved and removed by etching away the metal or these alloy layers with a low-solubility chemical solution to expose the nickel metal, cobalt metal, or these alloy layers, and then nickel. By etching with a chemical solution that has good solubility of metal, cobalt metal, or alloy layers of these and low solubility of copper, the undercut But very small, the shape is good, it could produce a superior high-density printed wiring board of adhesion of the copper foil.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/18 H05K 3/18 G J 3/46 3/46 S (72) Inventor Kenichi Shimizu 6 Shinjuku, Katsushika-ku, Tokyo 1-chome Mitsubishi Gas Chemical Co., Ltd. Tokyo factory F-term (reference) 4E351 AA01 BB01 BB30 BB33 BB35 CC06 CC07 DD04 DD19 DD21 DD54 GG11 GG13 4K024 AA09 AB01 BA01 BA11 BB11 BC02 DA07 FA05 GA16 4K057 WA11 WB03 WE10 WE03 WE10 WE03 WE25 WN01 5E343 AA02 AA12 BB14 BB17 BB24 BB44 BB45 BB67 BB71 DD33 DD43 DD76 GG06 GG08 GG11 5E346 AA06 AA12 AA15 AA22 AA32 AA51 BB15 CC08 CC32 CC37 DD12 DD25 DD32 DD33 EE13 HGG28H22H

Claims (2)

[Claims] (1) A nickel and / or cobalt or alloy layer thereof having a thickness of 0.1 to 3 μm is formed on one surface of a carrier sheet, and a nickel and / or cobalt or alloy layer having a thickness of 0.5 is further formed thereon. After removing the carrier sheet of the surface layer in the double-sided copper-clad plate or the multilayer double-sided copper-clad plate prepared by using the metal foil with a carrier sheet obtained by forming irregularities of ~ 5 μm as at least the outermost layer, (2) inside the hole Including 0.1 to the surface
1μm electroless copper plating is applied, (3) the electroless copper plating deposition layer is used as an electrode to form an electrolytic copper plating layer having a thickness of 0.5 to 3 μm, and (4) a necessary portion on the copper plating deposition layer. Form a plating resist layer for pattern electro-copper plating on (5) Attach a pattern copper plating of 6 to 30 μm by electro-copper plating on the copper surface where the plating resist layer is not formed, and remove the (6) plating resist. (7) At least the thin electrolytic copper layer and the electroless copper layer in the portion where the patterned copper plating layer is not formed are entirely etched with a chemical solution that does not dissolve nickel or cobalt or its alloy layer, and nickel or cobalt is removed. Or, after leaving the alloy layer, (8) has an ultrafine wire pattern characterized by being manufactured by etching the whole with a chemical solution that hardly dissolves copper and nickel or cobalt, or by dissolving and removing the alloy layer. The Method of manufacturing cement wiring board. 2. The carrier sheet is a copper foil.
A method for producing a printed wiring board having the described ultrafine wire pattern.