JPH0653631A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To realize a manufacturing method for printed wiring boards by which mass productivity equal to that of prior art screen process printing can be obtained along with making resist patterns much thinner and more accurate. CONSTITUTION:A first resist layer 3a, alkalescent (9<=pH<13) and soluble, is formed over the whole surface of a copper foil 2 clad on an insulating board 1. After a second pattern resist 4 of a specified pattern being a strong base (pH>=13) and soluble is formed on the first resist layer 3a, a first pattern resist 3 is formed by developing the first resist layer 3a with an alkalescent solution using the second pattern resist 4 as a make. The copper foil 2 is etched using these first and second pattern resists 3 and 4 as masks, and a wiring pattern having a specified pattern if formed by removing the first and second pattern resists with a strong base solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a printed wiring board which enables formation of a fine wiring pattern.

[0002]

2. Description of the Related Art In recent years, the density of wiring circuits for electronic devices has been increased,
Along with the increase in precision, printed wiring boards are required to form finer copper foil circuit patterns. As a method of forming a wiring pattern on this printed wiring board, a screen printing method has been widely used. In this screen printing method, the substrate 51
After laminating the copper foil 52 on the top (see FIG. 11), a resist ink soluble in a predetermined solvent is applied on the copper foil 52 by a screen printing machine using a mesh-shaped screen having a sol retained in the masking portion. The pattern resist layer 53 having a predetermined pattern is formed by printing and curing it (see FIG. 12). Then, using the pattern resist layer 53 as a mask, the copper foil 52 is
After the above etching, the pattern resist layer 53 is removed with a predetermined solvent to form a wiring pattern 54 having a predetermined pattern (see FIG. 13). This screen printing method has an advantage of high productivity.

However, the above screen printing method is
It has the following problems and has a drawback that the resolution is essentially low. That is, usually, as a pretreatment for printing the resist ink on the copper foil 52, in order to clean the surface of the copper foil 52, chemical polishing with an acid or the like and physical polishing using a rotating brush or the like are performed. ing.

However, by performing the polishing with such a rotating brush, the surface of the copper foil 52 has a depth of 1 mm.
Scratches of about μm will occur. Therefore, when the resist ink is printed on the copper foil 52, low-molecular components such as monomers and solvents in the ink bleed out (bleed out), and the bleeding ink causes scratches generated by the rotating brush. As the bleeding reaches the adjacent pattern, the bleeding portion functions as a mask at the time of etching after printing, and the copper foil 52 in this portion remains without being etched. Resulting in. Therefore, the copper foil 52 cannot be formed into a desired pattern, and there is a possibility that a defect such as a short circuit may occur.

Further, when the surface of the copper foil 52 is rough as described above, the ink wraps around to the back side of the plate at the time of printing the resist ink, causing problems such as ink bleeding and sagging. As described above, it is becoming difficult to sufficiently cope with the recent increase in the density of the circuit pattern on the printed wiring board by the conventional method of forming the wiring pattern by the screen printing method. Is the line / space ratio of 0.2 mm / 0.2 m
The limit is m (= line spacing / space spacing).

On the other hand, a method of forming a wiring pattern by a photo method is known. This photographic method is a method of forming a pattern resist layer as described above by bonding a dry film to a copper foil by thermocompression bonding, and then exposing and developing the film through a film on which a predetermined pattern shape is drawn.

In this photographic method, since no screen, roller or the like is used, there is no fear that the pattern will be misaligned or bleeding in the ink, and a resolution much higher than that of the screen printing method can be obtained.

However, this photographic method is poor in productivity and is only about ⅕ of the screen printing method (about 10 sheets / minute in the case of the screen printing method, whereas it is 2 in the case of the photographic method). Only about one sheet / minute). Therefore, this photographic method has a high production cost and is unsuitable for mass production.

[0009]

As described above, in the conventional method of forming a wiring pattern, it is difficult to obtain the excellent productivity while ensuring the precision of the pattern, and it is possible to increase the density of the wiring circuit. However, there is a limit to high precision. Therefore,
The present invention has been proposed in view of such a conventional situation, and manufactures a printed wiring board capable of obtaining mass productivity comparable to a conventional screen printing method while achieving high definition of a resist pattern. The purpose is to provide a method.

[0010]

The present invention has been proposed to achieve the above object. That is, in the method for manufacturing a printed wiring board of the present invention, a copper foil is laminated on an insulating substrate, and the first surface of the copper foil is soluble in a weak alkaline solution having a pH of 9 or more and less than 13. After forming a resist layer, and then forming a second pattern resist soluble in a strong alkaline solution having a pH of 13 or more in a predetermined pattern on the first resist layer, the first resist layer and the first resist layer are formed. The substrate on which the second pattern resist is formed is brought into contact with a weak alkaline solution, and the first resist layer is developed by using the second pattern resist as a mask to form the first pattern resist. After etching the copper foil using the first pattern resist and the second pattern resist as a mask, the second pattern resist and the first pattern resist are etched with a strong alkaline solution. It was removed, and is characterized in that to form wiring patterns with a predetermined pattern.

[0011]

By forming a weakly alkali-soluble first resist layer on the surface of a copper foil laminated on a substrate, scratches present on the surface of the copper foil polished for cleaning are described. Are absorbed by the first resist layer, and a smooth surface is obtained. Therefore, when the strong alkali-soluble second pattern resist is printed on the surface flattened by the first resist layer in a predetermined pattern corresponding to the wiring pattern, mainly low molecular weight molecules in the ink are used. There is no risk of component bleeding or bleeding. Therefore, the second
The pattern resist can be printed with a high-definition pattern.

Further, since the surface tension of this first resist layer is extremely lower than that of the copper foil, the ink wraps around under the masking sol of the screen when the second pattern resist is printed. Is less likely to occur and excellent in continuous printability.

By contacting the substrate on which the second pattern resist and the first resist layer are formed with a weak alkaline solution, the first resist layer exposed from the second pattern resist is selectively formed. Is developed to form a first pattern resist having substantially the same pattern as the second pattern resist.

Then, by etching the copper foil using the first pattern resist and the second pattern resist as a mask, only the copper foil under the first and second pattern resists remains, and other than that. The copper foil is etched away.

Since both the first pattern resist and the second pattern resist are soluble in a strong alkaline solution, the above first and second pattern resists are formed by using a strong alkaline solution after the above etching. By developing the resist, the remaining pattern resists are removed, and a wiring pattern having a desired pattern can be obtained.

Thus, by forming the second pattern resist by the printing method, sufficient productivity can be secured.

[0017]

EXAMPLES The present invention will be described below based on specific experimental results, but it goes without saying that the present invention is not limited to these examples.

First, as shown in FIGS. 1 and 2, a copper foil 2 is laminated on a substrate 1 having an insulating property. As the substrate 1, a multi-layer substrate (trade name: FR-4) having a plurality of copper foils 2 provided on the surface thereof, and a composite type substrate (trade name: CE-M) in which the copper foils 2 are laminated on both surfaces thereof. Although a substrate (brand name: FR-1) or the like, which is used only on one side, can be used, here, a composite type substrate is used, and a film of a copper clad laminate in which copper foil 2 is laminated on both sides. After forming a through hole penetrating in the thickness direction by drilling or the like, a plating layer was formed on the entire surface so as to cover the through hole.

It should be noted that FIG. 1 shows only one surface side of the substrate 1. The same applies to FIGS. 3 to 9 below. Further, here, for convenience, the wiring pattern of the copper foil 2 is represented by an ABC character pattern.

After that, the surface of the copper foil 2 is cleaned. As a method for cleaning the surface of the copper foil 2, any method usually used in the manufacturing process of this type of printed wiring board can be used, and generally, chemical polishing and physical polishing are combined. Used.

As the chemical polishing, surface treatment with an organic acid or an inorganic acid is generally used. Examples of the organic acid include malic acid, maleic acid, citric acid, malonic acid, and the like, and examples of the inorganic acid include phosphoric acid, hydrochloric acid, sulfuric acid, and the like. Further, a mixture of these organic acids and inorganic acids, ammonium sulphate, a soft etching solution containing hydrogen peroxide and sulfuric acid, etc. can also be used.

On the other hand, as the physical polishing, for example, brush polishing using a rotating brush or the like [for example, Tienex brush No. 320 (trade name) manufactured by DuPont, USA is used. ],
Scrub polishing [For example, use Perry brush manufactured by DuPont, USA, No. 1000 (trade name). ], Buffing [For example, flap buff manufactured by DuPont, USA, No. 1000 (trade name) is used. ] Etc. are general.

Next, as shown in FIGS. 3 and 4, a first resist layer 3a is formed on substantially the entire surface of the copper foil 2. The first resist layer 3a is formed by touch-drying (or curing) the coating film of the first resist ink A. As a result, unevenness due to the presence of scratches or the like generated on the surface of the copper foil 2 during the above-described cleaning causes the first resist ink A
Is absorbed, and the surface of the copper foil 2 is made flat.

First resist ink A used here
As the material, a material that is dry to the touch or cured by heat or ultraviolet rays and that is soluble in a weak alkaline solution having a pH of 9 or more and less than 13 is used. Further, considering the surface coverage of the copper foil 2, it is desirable that the copper foil 2 has a relatively low viscosity.

As the first resist ink A, any commercially available product can be used and is not particularly limited. Among these, as a material that is dried (or cured) by touch with heat, a resin obtained by adding an acid anhydride to a novolac type resin or a bisphenol type resin is usually used as a base polymer.

Examples of the acid anhydrides include dibasic acid anhydrides such as maleic anhydride, succinic anhydride, phthalic anhydride and tetrahydrophthalic anhydride, and aromatic polycarboxylic acids such as trimetic anhydride and pyrometic anhydride. Acid anhydrides and their derivatives [eg 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-
Dicarboxylic acid anhydride, etc.] and the like.

If desired, various fillers, organic solvents, etc. may be added to the thermosetting resist ink. As the filler, any conventionally known material can be used, and if specifically exemplified, it is insoluble in an alkaline solution of epoxy resin, phenol resin, melamine resin, polyester resin, EVA, vinyl chloride resin, or the like. Examples of such resins include barium sulfate, talc, and silica.

Similarly, any conventionally known material can be used as the above organic solvent. For example, cellosolve,
It is possible to use cellosolves such as butyl cellosol, carbitols such as carbitol and butyl carbitol and acetates thereof, and aromatic hydrocarbons such as toluene and xylene. In addition, a color pigment, a defoaming agent, an adhesion-imparting agent, a leveling agent, or the like used in this type of resist ink may be appropriately added.

In such a thermosetting resist ink, the carboxylic acid in the base polymer is dissolved in the alkaline solution by the reaction represented by the following formula (1) after the film formation.

[0030]

[Chemical 1]

As this thermosetting resist ink,
For example, PSR-4000 series, PER-20 (both trade names) manufactured by Taiyo Ink Mfg. Co., DSR-2200 series, DSR-2200Z series (both trade names) manufactured by Tamura Kaken Co., Ltd., K- manufactured by Toyo Ink Mfg. Co., Ltd. 100
0 (trade name) and the like.

On the other hand, it is dried (or cured) by touch with ultraviolet rays.
As a base polymer, a novolak type resin having acrylic acid or methacrylic acid in the molecule or a resin obtained by adding an acid anhydride to a bisphenol type resin is used as a base polymer. As the acid anhydride, any of the same compounds as in the case of the thermosetting resist ink can be used.

If necessary, a reactive diluent or the like may be added to the ultraviolet curable resist ink. As the reactive diluent, any of conventionally known materials can be used.
Hydroxyethyl acrylate, 2-hydroxypropyl acrylate, N-vinylpyrrolidone, melamine acrylate or water-soluble monomers such as methacrylates corresponding to the acrylates, diethylene glycol diacrylate, triethylene glycol diacrylate,
Propylene glycol diacrylate, mono- or diacrylates or methacrylates, mono-, di-, of polybasic acid and hydroxyalkyl (meth) acrylate
Examples include water-insoluble monomers such as tri- or higher polyesters.

In addition to the above, as in the case of the thermosetting resist ink, a color pigment, a defoaming agent, an adhesion promoter, a leveling agent, or the like may be added as needed.
Examples of the UV curable resist ink include TGR-100 series (trade name) manufactured by Taiyo Ink Mfg. Co., Ltd.
Etc.

The method of applying the first resist ink A as described above is not particularly limited, and a screen printing method, a roll coater method, a spray coater method, a curtain coater method,
It may be appropriately selected from the dipping method and the like.

After the application of the first resist ink A, when a thermosetting type is used as the first resist ink A, heating is performed in a box furnace, a wicket furnace, a tunnel furnace or the like. Then, the obtained coating film is dried (or cured) by touch. In this heating, the heating temperature is 5
The temperature is preferably 0 to 120 ° C. Heating temperature is 50 ℃
If it is lower than the above range, tack remains and the obtained coating film cannot be sufficiently dried (or cured) by touch. On the other hand, if the temperature is higher than 120 ° C., good development cannot be performed in the developing step described later.

On the other hand, when an ultraviolet curable type is used as the first resist ink A, the coating film obtained is subjected to ultraviolet irradiation by a UV curing oven or the like to dry (or cure) the film by touch.

The obtained first resist layer 3a may be formed on the entire surface including the inside of the through hole as described above.
At least a region where the first pattern resist 3 is formed by etching described later, that is, a resist formation pattern portion (a portion corresponding to the wiring pattern including the inside of the through hole).
It may be formed slightly wider.

The thickness of the first resist layer 3a is preferably in the range of 5 to 50 μm generally required as a resist film, and more preferably 10 to 20 μm. When the film thickness of the first resist layer 3a is less than 5 μm, the first resist layer 3a is affected by the unevenness due to the presence of scratches on the surface of the copper foil 2 generated during the above cleaning, and the first The surface of the resist layer 3a cannot be flattened. On the other hand, when the thickness is more than 50 μm, the undercut observed during the later-described development becomes remarkable and the desired line width cannot be stably obtained.

Subsequently, as shown in FIGS. 5 and 6, a positive type second pattern resist 4 is formed on the first resist layer 3a by a screen printing method in a predetermined pattern corresponding to the wiring pattern. . At this time, since the surface of the copper foil 2 is flattened by the first resist layer 3a as described above, in the case where ink scrapes or pinholes or unevenness due to scratches on the surface of the copper foil 2 exist. The bleeding that can be seen is extremely unlikely to occur. Further, since the ink is transferred onto the uniform surface of the first resist layer 3a as described above, it is difficult to cause the backing of the plate and is suitable for continuous printing. Therefore, the second pattern resist 4
Can be printed with a high-definition pattern.

When performing such screen printing,
As a screen to be used, any of those usually used can be used. For example, as the material of the gauze, Tetoron, stainless steel, nylon, etc. can be used, and the mesh roughness is preferably about 100 to 325 mesh, and most preferably about 200 to 300 mesh. . If the mesh is coarser than 100 mesh, the print resolution is poor. Conversely, if it is finer than 325 mesh, it is difficult for the ink to pass through the gauze, and blurring occurs, resulting in a defect.

The second resist ink B, which constitutes the second patterned resist 2, is touch-dry or hardened by heat or ultraviolet rays and is soluble in a strong alkaline solution having a pH of 13 or more. Material is used.

As the second resist ink B, any commercially available product can be used and is not particularly limited. Among these, those which are dried (or cured) by touch with heat include, for example, SER-400 series, S manufactured by Sanei Chemical Co.
ER-410 series, SER-420 series, SE
R-423 series (both are trade names), DA-110B, DA-180C, DA-200 manufactured by Sanwa Chemical Industry Co., Ltd.
B, DA-250C, DA-380B, DA-262C
(Both are trade names), WR-52 manufactured by Asahi Chemical Research Institute
0, WR-70 (both are trade names) and the like.

On the other hand, it is touch-dried (or cured) by ultraviolet rays.
For example, SER-14 manufactured by Sanei Chemical Co., Ltd.
00, SER-1405, SER-1406 (both are trade names), Taiyo Ink Mfg. Co., Ltd. X-66, X-77, X
-87 (both are trade names), UE manufactured by Sanwa Chemical Industry Co., Ltd.-
7000 (trade name) and the like.

After the printing, the second resist ink B is touch-dried (or cured) by a predetermined method. In addition, as a means for touch drying (or curing),
When the thermosetting type is used as the second resist ink B or the ultraviolet curing type is used, the same device as in the case of the first resist ink A can be used.

The film thickness of the second pattern resist 4 is
A range of 3-40 μm is suitable. If the film thickness of the second pattern resist 4 is thinner than 3 μm, pinholes and the like are likely to occur, and a good coating film cannot be obtained.
On the other hand, if it exceeds 40 μm, the resolution of printing may be deteriorated.

Then, as shown in FIGS. 7 and 8, the first resist layer 3a is developed with a weak alkaline solution using the second pattern resist 4 as a mask. Here, since the second pattern resist 4 is soluble in a strong alkaline solution, the second pattern resist 4 is not removed, and the first resist layer exposed from the second pattern resist 4 is not removed. Only 3a is selectively developed and removed. As a result, the first pattern resist 3 having substantially the same pattern as the second pattern resist 4 is formed.

When developing the first pattern resist 3, the second pattern resist 4 is formed with high precision.
Since this is used as a mask, only the first resist layer 3a exposed from the second pattern resist 4 is faithfully developed, and the first pattern resist 3 can be accurately formed into a desired pattern. it can.

At this time, in order to develop only the first resist layer 3a exposed from the second pattern resist 4, only the first resist layer 3a is used so that only the first resist layer 3a is soluble. It is necessary to set the pH of the above to 9 or more and less than 13. When the pH of the developer is less than 9, the above first
If the resist layer 3a of No. 1 cannot be sufficiently developed, and conversely the pH exceeds 13, the above first resist layer 3
Not only a, but also the second pattern resist 4 is developed and removed, so that a resist for patterning the copper foil 2 described later cannot be formed.

As such a weak alkaline solution, any of those usually used for developing a photographic developing ink can be used. For example, a 1 to 3% Na ₂ CO ₃ solution or the like is used under normal developing conditions. It can be used.

Then, the first pattern resist 3 is formed.
Then, the copper foil 2 is etched using the second pattern resist 4 as a mask. As a result, only the copper foil 2 exposed from the second pattern resist 4 (and the first pattern resist 3) is selectively removed and patterned with a predetermined pattern. Here, since the second pattern resist 4 and the first pattern resist 3 formed with high precision are used as resists, they are exposed from the second pattern resist 4 (or the first pattern resist 3). Only the copper foil 2 is faithfully developed, and a desired pattern can be accurately patterned.

In this etching, any of the methods usually used for manufacturing a printed wiring board of this type can be used, and wet etching, dry etching or the like can be used. good. However, when performing wet etching, it is necessary to select an acidic etchant such as cupric chloride or ferric chloride as an etching solution. When an alkaline etchant is used as the etching liquid, the first pattern resist 3 and the second pattern resist 4 are dissolved at the same time when the copper foil 2 is etched, and the resist function cannot be exhibited.

Then, using a strong alkaline solution, the first pattern resist 3 and the second pattern resist 4 described above are used.
To remove. As a result, as shown in FIG. 9 and FIG.
Only the copper foil 2 patterned as described above remains,
Wiring pattern 5 having a desired pattern on the substrate 1
Is formed.

At this time, in order to completely remove the second pattern resist 4 and the first pattern resist 3 while leaving only the patterned copper foil 2, the pH of the solution used is 13 or more. There is a need to. If the pH of the solution is less than 13, the second pattern resist 4 and the first pattern resist 3 cannot be sufficiently removed.

As such a strong alkaline solution, any of those which are usually used for removing a patterned resist can be used, and for example, a NaOH solution or the like can be used under ordinary developing conditions.

In the production of such a printed wiring board, the first pattern resist 3 and the second pattern resist 4 are formed by the screen printing method. It is possible to secure comparable excellent productivity.

Various printed wiring boards were actually manufactured on the basis of the method for manufacturing a printed wiring board as described above. Example 1 In this example, a first resist layer was formed by a screen printing method using a thermosetting first resist ink on a composite copper-clad laminate, and a heat treatment was performed on the first resist layer. This is an example of producing a printed wiring board by screen-printing a curable second resist ink in a predetermined pattern and then etching a copper foil.

That is, first, a commercially available paper phenol copper clad laminate [MCL-437F (trade name) manufactured by Hitachi Chemical Co., Ltd., plate thickness 1.6 mm, copper foil thickness 35 μm] was 335 mm × 251 m.
After cutting into m, the surface of the copper foil was cleaned with a scrubbing surface maker manufactured by Ishii Inscription Company. In addition, in this cleaning,
After washing with 5% sulfuric acid, flap buff (1000
No.) is used for buffing, followed by a perry brush (100
After scrubbing with No. 0) and ultrasonic cleaning, it was dried.

Next, the first resist ink A was coated on the surface of the copper foil with a printing machine (trade name: New Long LS-5).
0) screen-printed. The first resist ink A is DSR-22 manufactured by Tamura Kaken Co., Ltd.
00 (trade name) was used. The printing machine used had a plate specification of Tetron 180 mesh and an emulsion of 20 μm thick. Also, the first applied
The coating area of the resist ink A is 330 mm x 240
It was mm.

Then, it was heated at a temperature of 80 ° C. for 15 minutes in a box furnace (trade name: Tabai Espec PHH-200),
The first resist ink A was touch-dried. The film thickness of the obtained first resist layer was measured by a surface roughness measuring device (trade name: Surfcom) manufactured by Tokyo Seimitsu Co., Ltd.
It was 0 μm.

Then, the second resist ink B was screen-printed on the first resist layer in a predetermined pattern by a printing machine (trade name: New Long LS-50).
As the second resist ink B, SER-420 (trade name) manufactured by Sanei Chemical Co., Ltd. was used. In addition, the second
The resist ink B pattern of No. 1 has a copper foil circuit pattern design standard of line / space = 150 μm / 150 μm
The product pattern for a camcorder of The above-mentioned printing machine has Tetron 250 mesh plate specifications and 12 emulsions.
Using a sheet having a thickness of μm, 200 sheets were continuously printed. The application area of the first resist ink A was 330 mm × 240 mm.

Then, it was heated at a temperature of 80 ° C. for 10 minutes in a box furnace (trade name: Tabai Espec PHH-200),
The second resist ink B was touch-dried. The film thickness of the obtained second pattern resist was 8 μm. Subsequently, the first resist layer was developed with a weak alkaline solution and patterned into a pattern substantially the same as the second pattern resist to form a first pattern resist.

In this development, a 3% Na ₂ CO ₃ solution was used as the weak alkaline solution, the temperature was 30 ° C., the development time was 80 seconds, and the spray pressure was 2.0 kg / cm ² .

After this development, the copper foil was selectively etched by the spray etching apparatus using the first and second pattern resists as resists, and the copper foils exposed from the first and second pattern resists were removed by etching. . In this etching, a ferric chloride solution was used as an etchant. Then, the first and second pattern resists were removed by using a peeling device, and only the copper foil patterned by the above etching was left to obtain a printed wiring board having a desired wiring pattern. In the peeling device, a 2% NaOH solution is used and the processing time is 2 minutes.

Example 2 The first resist ink A used in the above Example 1 was changed to PSR-4000 (trade name) manufactured by Taiyo Ink Manufacturing Co., Ltd., and the second resist ink B was manufactured by Sanwa Chemical Industry Co., Ltd. A printed wiring board was produced in the same manner as in Example 1 except that DA-180C was used.

Example 3 This example is an example of producing a printed wiring board by using an ultraviolet curable type as the first resist ink and a thermosetting type as the second resist ink. . First, using the same copper-clad laminate as used in Example 1 above, after cleaning the copper-clad laminate as described above, the surface of the copper foil was covered with the first resist ink A. Screen printing was performed using a printing machine (trade name: New Long LS-50). As the first resist ink A, TGR-100 series (trade name) manufactured by Taiyo Ink Mfg. Co., Ltd. was used.

After that, ultraviolet irradiation is carried out in a conveyor UV furnace (trade name: HMW-713) using a high pressure mercury lamp manufactured by Oak Co., and the first resist ink A is touch-dried to give a first resist layer. Was formed. The integrated light quantity at the time of this ultraviolet irradiation was 1000 mJ / cm ² .

Next, the second resist ink B was screen-printed on the first resist layer by a printing machine (trade name: New Long LS-50) in a predetermined pattern.
As the second resist ink B, SER-420 (trade name) manufactured by Sanei Chemical Co., Ltd. was used. Then, the second resist ink B is heated in a box furnace (trade name: Tabai Espec PHH-200) at a temperature of 70 ° C. for 10 minutes.
Was touch dried.

Subsequently, in the same manner as in Example 1, the first resist layer was developed with a weak alkaline solution to form a first pattern resist, and then the copper foil was etched with a spray etching apparatus. Then, the first pattern resist and the second pattern resist were removed by using a peeling device to obtain a printed wiring board having a desired wiring pattern.

Example 4 This example is basically the same as Example 3 except that the first resist ink and the second resist ink used are both UV curable. It is an example of manufacturing a substrate. Second used in Example 3 above
SER-1405 manufactured by Sanei Chemical Co., Ltd.
(Trade name), and the conditions for UV irradiation at the time of touch-drying the second resist ink are the same as those at the time of UV irradiation for the first resist ink in Example 3 described above, and other conditions are the same as described above. A printed wiring board was produced in the same manner as in Example 3.

Example 5 This example is basically the same as Example 3 except that the first resist ink and the second resist ink used are both ultraviolet curable inks. It is an example of manufacturing a substrate. First used in Example 3 above
The resist ink of No. 1 was changed to the ink prepared as follows, and the second resist ink was changed to X-87 (trade name) manufactured by Taiyo Ink Mfg. Co., Ltd.
And the accumulated light amount of the conveyor UV furnace (trade name: HMW-713) using a high pressure mercury lamp manufactured by Oak Co., which was used for touch-drying the second resist ink, was 1200 mJ / cm.
^{As 2} , the printed wiring board was manufactured in the same manner as in Example 3 except above.

<Preparation of First Resist Ink> 100 g of styrene-maleic acid resin (here, SMA-1440, trade name, manufactured by Arco Chemical Co., Ltd.) was used as 2-.
Solution A prepared by dissolving 68 g of hydroxyethyl acrylate and 12 g of dimethylaminoethyl methacrylate in 40 g of ethylene glycol diacrylate,
A solution B prepared by dissolving 100 g of cresol novolac epoxy resin (trade name: N-695) manufactured by Dainippon Ink and Chemicals, Inc. in 100 g of isobornyl acrylate was mixed and dispersed with the following materials to obtain a resist ink.

Composition of resist ink Solution A 33.3 parts by weight Solution B 33.3 parts by weight 2MZA (manufactured by Shikoku Chemicals) 2.9 parts by weight Clay 20.0 parts by weight 2 Ethylanthraquine 2.9 parts by weight CTBN (Made by Ube Industries) 7.6 parts by weight

Comparative Example First, the same copper clad laminate as used in Example 1 was used, and SER-1405 (trade name) manufactured by Sanei Chemical Co., Ltd. was used as a resist ink on the copper clad laminate. After continuously printing 200 sheets by the conventional screen printing method, UV irradiation was performed in the same manner as the UV irradiation for the first resist ink in Example 3 above, and the obtained coating film was dried by touch. The printing machine used for printing the resist ink was the same as that used for printing the second resist ink in Example 1 above.

Subsequently, the obtained pattern resist was used to etch the copper foil, and the resist was removed to produce a printed wiring board.

In each printed wiring board manufactured as described above, in order to evaluate the accuracy of the obtained wiring pattern, the occurrence of short circuit and disconnection when a predetermined voltage was applied to the wiring pattern was examined. Examined. The results are shown in Table 1 below.

[0077]

[Table 1]

As shown in Table 1, in Examples 1 to 4,
After printing 200 sheets of the second resist ink continuously,
In each case, good printability is maintained from the initial (10th sheet) to the 200th sheet without causing blurring or bleeding of the ink, and the copper foil circuit pattern obtained as a result is formed with a high-definition pattern. I found out that

On the other hand, in the comparative example, bleeding and bleeding occurred during printing of the resist ink, and the line width tended to become thick from the beginning of printing. In addition, it was found that a short circuit occurred around the 150th sheet from the start of printing, and a good copper foil circuit pattern could not be formed. From this, in the case of applying this embodiment, the design standard of the copper foil circuit pattern is line / space = 150 μm / 1.
It has been clarified that the wiring pattern can be accurately formed even when the thickness is 50 μm.

[0080]

As is apparent from the above description, in the present invention, a first pattern is formed by a printing method on the first resist layer formed by coating so as to cover the surface of the cleaned copper foil. Since the pattern resist No. 2 is formed, it is extremely unlikely that ink blurring, pinholes, or ink bleeding, which is seen when unevenness is present on the copper foil surface, occurs. Therefore, the second pattern resist can be printed with a high-definition pattern.

In addition, the second portion formed with high precision in this way
Pattern resist (or the first pattern resist developed using this second pattern resist as a mask)
Since the copper foil is selectively etched by using as a mask, the copper foil can be faithfully patterned into a desired pattern. Therefore, according to the present invention, it is possible to provide a printed wiring board having a highly reliable wiring pattern and excellent reliability.

Further, in the present invention, since the printing method is basically used as the method for forming the second pattern resist and the first pattern resist, it is possible to realize the high definition of the wiring pattern as described above. At the same time, the processing speed can be improved, and mass productivity comparable to the conventional printing method can be realized.

[0083]

[Brief description of drawings]

FIG. 1 is a view for explaining one embodiment to which a method for manufacturing a printed wiring board according to the present invention is applied in the order of steps, and is a step sectional view showing a copper foil laminating step.

FIG. 2 is a plan view showing a copper foil laminating step.

FIG. 3 is a process sectional view showing a first resist layer forming process.

FIG. 4 is a plan view showing a first resist layer forming step.

FIG. 5 is a process sectional view showing a second pattern resist forming process.

FIG. 6 is a plan view showing a second pattern resist forming step.

FIG. 7 is a process sectional view showing a process of forming a first patterned resist.

FIG. 8 is a plan view showing a step of forming a first patterned resist.

FIG. 9 is a process cross-sectional view showing a copper foil etching process.

FIG. 10 is a plan view showing a copper foil etching step.

FIG. 11 is a process sectional view showing a process of forming a wiring pattern.

FIG. 12 is a plan view showing a step of forming a wiring pattern.

FIG. 13 is a process sectional view showing a copper foil laminating process in a conventional screen printing method.

FIG. 14 is a process sectional view showing a pattern resist printing process by a conventional screen printing method.

FIG. 15 is a process sectional view showing a wiring pattern forming process by a conventional screen printing method.

Claims (1)

[Claims] 1. A copper foil is laminated on an insulating substrate, and a first resist layer soluble in a weak alkaline solution having a pH of 9 or more and less than 13 is formed on the entire surface of the copper foil, and then, P with a predetermined pattern on the first resist layer
After forming a second pattern resist soluble in a strong alkaline solution having H of 13 or more, the substrate on which the first resist layer and the second pattern resist are formed is contacted with a weak alkaline solution, After developing the first pattern resist by using the second pattern resist as a mask to form the first pattern resist, and subsequently etching the copper foil by using the first pattern resist and the second pattern resist as a mask A method for manufacturing a printed wiring board, comprising: removing the second pattern resist and the first pattern resist with a strong alkaline solution to form a wiring pattern having a predetermined pattern.