JPH054840B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a printed wiring board, and particularly to a method for manufacturing a printed wiring board having through holes. (Prior Art) A variety of printed wiring boards have been manufactured, including those in which conductor circuits are formed on both sides of an insulating substrate, and those in which an insulating substrate is made of multiple layers and a conductor circuit is formed in each insulating layer. It has been widely used as a component in many electronic devices ranging from consumer to industrial use. When forming a printed wiring board in which conductor circuits span multiple layers in this way, through holes are usually used to establish continuity between each conductor circuit layer, but the formation of the through hole itself and the connection between the through hole and the through hole are difficult. Due consideration shall be given to ensuring continuity with conductor circuits. In particular, as the density of electronic components increases in recent years, there is a need to increase the density of each conductor circuit on the printed wiring board itself on which these electronic components are mounted. Naturally, the reliability of through holes that connect conductor circuits to each other is also important. As a conventional method for forming conductor circuits and through holes for connecting the conductor circuits in such printed wiring boards, a so-called subtractive method has been employed. Simply put, this subtractive method is a method of removing unnecessary parts such as conductor circuits by etching etc.
Using a copper-clad laminate as a starting material, the copper foil is dissolved and removed by etching to form a desired conductor circuit. However, recently, full additive methods have been attracting attention for the following reasons. The full additive method has a simple manufacturing process, which can reduce the number of steps by half compared to the conventional subtractive method, and the ability of electroless plating to cover through holes is good.
This method is superior to the subtractive method because it is more suitable for high-density wiring than the conventional subtractive method because the accuracy of forming the wiring pattern is determined only by the precision of the resist. The most common fully additive method is a method using an adhesive containing a diene synthetic rubber as described below. This method, as exemplified in, for example, Japanese Patent Application Laid-Open No. 16129/1983, mainly consists of the following steps. That is, as shown in Fig. 2, (a) forming an adhesive layer containing diene rubber on the surface of the insulating substrate; (b) forming a through-hole in the necessary locations of the insulating substrate on which such an adhesive layer has been formed; Step of forming a hole to become a hole; (c) Roughening the surface of the adhesive layer; (d) Applying a catalyst to the entire surface of the roughened adhesive layer to improve plating precipitation. (e) A process of covering the surface of the adhesive layer other than the conductor circuit forming portion with a plating resist; (f) A process of forming a conductor circuit by electroless plating. It consists of By the way, in the case of the full additive method using an adhesive containing this diene-based synthetic rubber, it is an extremely important condition that the material forming the adhesive layer also contains the diene-based rubber. The reason for this is that the surface of the adhesive layer must be roughened to form a so-called anchor for good and strong electroless plating adhesion. This is because it becomes possible only by using a diene rubber that is easily eluted by chemicals such as. In addition, this diene rubber is easily eluted by chemicals, so when immersing the entire insulating substrate in the chemicals, it is necessary to do so within a short period of time. Therefore, it is possible to avoid unnecessary elution due to immersion of the adhesive layer portion in a chemical. In other words, generally when roughening an adhesive layer, the material such as an insulating substrate is immersed in a chemical such as an oxidizing agent, but if you want to roughen only the surface of the adhesive layer, At this time, the inside of the hole that has already been formed to become a through hole may be roughened more than necessary. If the inside of the hole is roughened more than necessary in this way,
The roughening of the inner wall of the hole increases the unevenness, and if a through-hole is plated inside the hole to form a through-hole, the reliability of the conduction will be poor. The electroless plating solution permeates along the glass cloth, greatly reducing the insulation resistance between the through holes. Therefore, the fully additive method, which uses an adhesive containing diene rubber that can be eluted within a short time by chemicals such as oxidizing agents, has the advantage that it does not cause unnecessary roughening of the inside of the through hole. This is an excellent technique. In other words, in the fully additive method of forming an adhesive layer containing this diene rubber, the surface of the adhesive layer can be roughened without adversely affecting others; However, the purpose of manufacturing printed wiring boards can be fully demonstrated. However, the fully additive printed wiring board manufacturing method using adhesives containing diene rubber requires considerably strict manufacturing conditions when roughening the adhesive containing diene rubber. In order to ensure elution, the temperature of the oxidizing agent must be set, the immersion time in the oxidizing agent must be strictly controlled, and these conditions must be adjusted according to the amount of diene rubber contained in the adhesive. Strict conditions such as settings must be adhered to. In addition, as another example of the manufacturing method of fully additive wiring boards, an adhesive with excellent heat resistance is used, which is made by dispersing fine inorganic powder such as silica or calcium carbonate in a hardening resin such as epoxy resin, polyimide resin, or phenol resin. May be used. In this case, the anchor is formed by selectively eluting inorganic fine powder dispersed in the curable resin. When using silica as an inorganic fine powder,
Generally, hydrofluoric acid-based chemicals are used to dissolve silica, so for laminates reinforced with glass cloth, the process involves roughening the surface of the adhesive layer after forming through-holes. cannot be adopted. This is because when the silica in the adhesive layer is eluted by the hydrofluoric acid-based chemicals, the glass cloth exposed inside the through-hole is also eluted, making the inner wall of the hole more uneven. When through-hole plating is applied to the inside of the hole, the reliability of the conduction becomes poor. Furthermore, when calcium carbonate is used as an inorganic fine powder, hydrochloric acid-based chemicals are generally used to elute the calcium carbonate, so the concentration and temperature of the chemicals must be precisely set to ensure this elution. , strict conditions such as strictly limited immersion time control in this chemical must be observed. Furthermore, as another example of the method for manufacturing a fully additive wiring board, heat-resistant resin powder that is soluble in oxidizing agents and has been cured in advance has the property of becoming hardly soluble in oxidizing agents by curing treatment. An adhesive dispersed in an uncured heat-resistant resin may be used. This is a patent application filed by the present inventors, and in this case, the solubility of the heat-resistant resin matrix and the heat-resistant resin fine powder dispersed in the matrix with respect to oxidizing agents is determined. It takes advantage of the difference. In this case, it is also possible to use a combination of an epoxy resin that is easily soluble in the oxidizing agent as the heat-resistant resin fine powder and an epoxy resin that is relatively insoluble in the oxidizing agent as the heat-resistant resin that is the matrix. An adhesive layer made of this combination is formed on a regular glass/epoxy resin laminate, and when the surface of the adhesive layer is roughened with a chromic acid-based chemical, holes that become through holes are formed. When this happens, the resin on the inner wall of the hole that becomes the through-hole becomes greatly roughened, and when this hole is plated to form a through-hole, the reliability of the conduction becomes poor. The electroless plating solution permeates along the glass cloth that makes up the epoxy resin laminate, greatly reducing the insulation resistance between the through holes. As mentioned above, adhesives containing diene rubber can be used for some printed wiring boards, but as the level of required performance such as heat resistance and moisture resistance for printed wiring boards increases, In some cases, it is not possible to use adhesives containing diene rubber, and it may be desirable to use adhesives that do not contain diene rubber. In such cases, the adhesive layer is often very difficult to roughen, and must be roughened under very strict conditions. There is a particularly serious problem that the inner wall of the hole is greatly roughened, and it is difficult to employ the process shown in FIG. 2. On the other hand, if the adhesive layer is roughened before forming the hole that will become the through hole, the roughened surface formed in advance may be damaged or dirt may adhere to the roughened surface during the drilling process. As a result, the anchoring effect of the roughened surface cannot be sufficiently exerted. Therefore, the present inventors have conducted extensive research into a method for manufacturing printed wiring boards that can solve the above-mentioned problems in through-holes due to the unprecedented level of performance required for printed wiring in recent years. Not only can adhesives containing diene rubbers be used by using the method described in the claims that have been concluded to have high applicability, but also all other adhesives that do not contain diene rubbers can be used. They discovered a new method for manufacturing printed wiring boards that can also use chemicals, and completed the present invention. (Problems to be Solved by the Invention) The present invention has been made based on the above-mentioned circumstances, and the problem to be solved is to obtain a level of performance required for recent printed wiring boards that is unprecedented. When using the full additive method, which is the conventional method for manufacturing printed wiring boards, the materials that can be used are limited. Moreover, strict manufacturing conditions must be observed that have little industrial applicability. The purpose of the present invention is to incorporate a fully additive method suitable for manufacturing printed wiring boards by devising the manufacturing process, while using manufacturing conditions that are highly applicable in industry. This makes it possible to easily manufacture printed wiring boards with through-holes that are highly reliable and can meet the performance levels required for printed wiring boards in recent years. There are no restrictions on the materials used,
It is an object of the present invention to provide a manufacturing method with a simple structure that improves the workability of processing holes to be through holes. (Means and effects for solving the problems) The means taken by the present invention to solve the above problems are explained with reference to FIG. 1 corresponding to the embodiment. In the method for manufacturing a printed wiring board in which desired conductor circuits 16 and through-holes are plated on the surface of the conductor circuit 16 by plating, the formation of the conductor circuits 16 and the through-holes are performed after the following steps are performed. A method for manufacturing a printed wiring board 10 characterized by: forming an adhesive layer 12 on the surface of an insulating base material 11; roughening the surface of the adhesive layer 12 with an oxidizing agent; a step of masking the exposed surface with a mask material 13; a step of forming holes 14a that will become through holes 14 at necessary locations in the insulating base material 11 and adhesive layer 12 with this mask on; the mask material 13 on the surface That is, in the present invention, the adhesive layer 12 is first formed directly on the surface of the insulating base material 11, and the surface of this adhesive layer 12 is roughened with an oxidizing agent. Next, the roughened surface of this adhesive layer 12 is covered with a mask material 1.
3, holes 14a that will become through holes 14 are formed in the required locations of the insulating base material 11 and the adhesive layer 12, and then the mask material 13 on the surface of the adhesive layer 12 is removed. Then, the catalyst 1 is applied to the roughened adhesive layer 12 and all inside the holes 14a.
5, the necessary conductor circuits 16 are formed and through-holes are plated. Next, the above configuration according to the present invention will be explained in more detail with reference to FIG. First, FIG. 1 shows the manufacturing method according to the present invention step by step. In this case, from an insulating base material 11 which is a starting material, a printed product having through holes 14 and a conductive circuit 16 is produced. The steps up to the wiring board 10 are indicated by consecutive round numbers in the order of the steps. That is, in the manufacturing method according to the present invention,
First, the adhesive layer 12 is formed on the surface (both surfaces in this embodiment) of the insulating substrate 11. The insulating base material 11 used in this case may be a general material, such as a glass/epoxy resin laminate, a glass/polyimide resin laminate, a metal or ceramic substrate filled with holes and covered with resin, or a build-up method, etc. An insulating layer, etc., which is the outermost layer of a multilayer wiring board made up of multiple layers, is used. Furthermore, the material for forming the adhesive layer 12 may be any of the common materials mentioned in the prior art, and it is not necessarily necessary to use an adhesive containing diene rubber. Of course, an adhesive containing diene rubber may be used as the material for forming the adhesive layer 12. Next, without forming holes 14a that will become through holes 14, the surface of each adhesive layer 12 formed as described above is used to form anchors for good adhesion of conductor circuits 16, etc., which will be described later. It is roughened by the oxidizing agent. General roughening conditions may be adopted as the roughening conditions, and the roughening conditions such as the roughening time can be relaxed. This is because when performing this roughening, the insulating base material 11
Since the hole 14a does not exist at all,
Only the surface of each adhesive layer 12 is exposed to roughening chemicals such as oxidizing agents, and therefore roughening conditions such as roughening time or roughening temperature cannot be determined solely by adhesive layer 12. Because it can be done. After roughening the surface of each adhesive layer 12 as described above with an oxidizing agent, the roughened surface is coated with the mask material 1.
3, and holes 14a, which will become through holes 14, are formed at necessary locations in the insulating base material 11 and the adhesive layer 12 while being masked. The reason why the surface roughened in this way is masked with the masking material 13 is to form the hole 14a that will become the through hole 14 in the step of step 1, but each adhesive layer 12 that has been roughened during this hole drilling operation is This is to prevent damage to the surface. In other words, industrial hole-drilling work is generally performed mechanically in large quantities and simultaneously, and in this case, the adhesive layer 12 of another substrate directly stacked on the adhesive layer 12 or the presser plate may come into contact with it. In such cases, the adhesive layer 12 is
In order to avoid damage to the roughened surface, the roughened surface is first masked with a masking material 13. The mask material 13 used in this case is as follows:
Any method may be used as long as it can sufficiently protect the roughened surface of each adhesive layer 12 from the heat generated during drilling of the insulating base material 11 and shocks during handling, but It must be able to be peeled off. Materials that meet these conditions include polyvinyl alcohol, rubber (preferably photosensitive ones), and films with adhesives, among which polyvinyl alcohol and rubber are used in liquid form. Therefore, it is more advantageous because it can be easily masked without damaging the roughened surface of the insulating base material using a dip method, a spray method, or the like. Then, the mask material 1 on the surface of each adhesive layer 12 is
After the catalyst 15 is removed, the catalyst 15 is formed all over the roughened adhesive layer 12 and the holes 14a. In the subsequent steps, a plating resist is formed at a predetermined location on the surface of each adhesive layer 12 by a normal method, and a predetermined plating such as electroless plating is applied to form the conductor circuit 16 and the through-hole. A hole 14 is formed. Of course, when carrying out the manufacturing method according to the present invention, the above-mentioned steps (-) which are not directly related to the present invention may be changed as follows. That is, after removing the mask material 13 on the surface of each adhesive layer 12, a plating resist is applied to a predetermined location on the surface of each adhesive layer 12 by a normal method,
Adhesive layer 1 exposed from this plating resist
2 and the catalyst 15 is formed in all of the holes 14a,
The conductive circuit 16 and the through-holes 14 may be formed by applying a predetermined plating process such as electroless plating. Furthermore, as a matter of course, if the catalyst is previously formed in the insulating base material and the adhesive layer formed on its surface, the above steps are unnecessary. (Example) Next, the present invention will be explained in detail according to an example. Example 1 (1) Epoxy resin (product name manufactured by Mitsui Petrochemical Co., Ltd.:
TA-1800) was dried and cured in a hot air dryer at 160℃ for 1 hour, then at 180℃ for 4 hours,
This hardened epoxy resin is coarsely pulverized and then frozen in liquid nitrogen using a supersonic jet pulverizer (trade name, manufactured by Nippon Neumatics Industry Co., Ltd.:
The particles were finely pulverized using an air classifier (manufactured by Japan Donaldson Co., Ltd., trade name: Labojitsu), and the average particle size was 1.6 μm.
A fine powder of epoxy resin was made. (2) 60 parts of polyfunctional epoxy resin (product name: Epicoat-1031 manufactured by Yuka Shell Co., Ltd.), 40 parts of bisphenol A type epoxy resin (trade name: Epicoat-1001 manufactured by Yuka Shell Co., Ltd.) and imidazole (Shikoku) as a curing agent. Dissolve 4 parts of Kasei's product name: 2PZ) in butyl cellosolve, and add 70 parts of the epoxy resin fine powder prepared in (1) to 100 parts of the solid content of this composition.
An adhesive was prepared by blending the adhesives in the following proportions, mixing with three rolls, and adjusting the viscosity to 500 cps with butyl cellosolve. (3) Using a roller coater (product name: MRC-450, manufactured by Thermatronics Trading Co., Ltd.), apply this adhesive to a glass epoxy insulating board (manufactured by Toshiba Chemical Company, product name: Toshiba Tecolite Laminate) to which the copper foil is not attached. 1 at 100℃ after coating both sides of EL).
After drying and curing for 5 hours at 150℃,
An adhesive layer with a thickness of 15 μm was formed. (This state is shown in Figure 1.) (4) This substrate is placed in 500 g of chromic anhydride/aqueous solution.
After being immersed at 70° C. for 20 minutes to roughen the surface of the adhesive layer with the oxidizing agent, it was immersed in a neutralizing solution (trade name: PM950, manufactured by Shipley) and washed with water.
(This state is shown in Figure 1.) (5) Polyethylene acrylic film with adhesive (trade name: E-74M, manufactured by Sumilon Corporation) is applied to the substrate whose surface of the adhesive layer has been roughened with an oxidizing agent. A mask was formed using this film on the roughened surface of the adhesive layer. (This state is shown in Figure 1.) (6) At the desired position, use an NC multi-axis drilling machine (product name: Mark V manufactured by Excellon Automation).
A through hole with a diameter of 0.7 mm was drilled using a drill bit. (This state is shown in Figure 1.) (7) Next, the film mask was removed and washed with water. (This state is shown in FIG. 1.) (8) A palladium catalyst (trade name: Cataposi 44, manufactured by Shipley) was formed on the entire surface of the substrate. (This state is shown in Figure 1.) (9) Laminate a photosensitive dry film for additives (product name: Fotec SR-3200, manufactured by Hitachi Chemical Co., Ltd.) on the substrate on which the catalyst has been formed.
A plating resist was formed by exposure and development.
(This state is shown in Figure 1.) (10) Next, after performing an activation treatment, the plated film was immersed in an electroless plating solution for additive use having the composition shown below for 11 hours until the thickness of the plated film was approx. A double-sided through-hole wiring board was manufactured by applying 25μm electroless copper plating. (This state is shown in Figure 1.) Copper sulfate (CuSO ₄ 5H ₂ O) 0.06 mol / Formalin (37%) 0.30 mol / Caustic soda (NaOH) 0.35
Mol/EDTA0.12mol/a little additive Plating temperature:
70-72°C PH: 12.4 Example 2 (1) 60 parts of phenol novolak type epoxy resin (manufactured by Yuka Shell Co., Ltd., trade name, E-154), bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Ltd., trade name, E-154).
Product name, E-1001) 40 parts, 2-phenyl-4-
Methyl-5-hydroxymethylimidazole (manufactured by Shikoku Kasei Co., Ltd., trade name, 2P4MHZ) 4 parts, epoxy resin fine powder (manufactured by Toray Industries, Ltd., trade name Trepar EP-B, average particle size 0.5 μm) 15 parts, benzoguanamine resin fine powder (manufactured by Nippon Shokubai Kagaku Co., Ltd., trade name, Eposter S-6) A composition consisting of 35 parts was mixed using three rolls, and the viscosity was adjusted to 500 cps with a butyl cellosolve solvent to prepare an adhesive. (2) Apply this adhesive to both sides of a glass epoxy insulating board using a roller coater in the same manner as in Example 1, and dry and cure at 100°C for 1 hour and then at 150°C for 7 hours to form an adhesive layer. Formed. (This state is shown in Figure 1.) (3) Place this substrate in 500g of chromic anhydride/aqueous solution.
After being immersed at 70° C. for 20 minutes to roughen the surface of the adhesive layer with the oxidizing agent, it was immersed in a neutralizing solution and washed with water. (This state is shown in Figure 1.) (4) Polyvinyl alcohol (manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd., trade name, Gohsenol EG-30) 10 %
Apply an aqueous solution by dip coating method and heat at 60℃.
After drying for 15 minutes, a mask made of a polyvinyl alcohol polymer film was formed on the roughened surface of the adhesive layer. (This state is shown in FIG. 1.) (5) Next, in the same manner as in Example 1, through holes were bored at required locations. (This state is shown in Fig. 1.) (6) After providing the through holes, the mask was dissolved and peeled off by immersing it in a hot water bath at 80°C for 3 minutes. (This state is shown in Figure 1.) (7) Next, add 500g of chromic acid to the aqueous solution at 60℃ for 2 hours.
The adhesive layer was immersed for a minute to dissolve and remove burrs generated around the through holes. (8) Thereafter, a double-sided board was manufactured in the same manner as in Example 1. (This state is shown in Figure 1.) Example 3 (1) Epoxy resin (manufactured by Mitsui Petrochemicals, trade name,
Fused silica fine powder (manufactured by Ryumori Co., Ltd., trade name, CRS-1101-20) 80 parts by coupling 100 parts of TA-1850) with a silane coupling agent (manufactured by Shin-Etsu Silicone Co., Ltd., trade name, KBM403)
The mixture was mixed using a three-roll roll, and the viscosity was adjusted to 500 cps using a butyl cellosolve solvent to prepare an adhesive. (2) Apply this adhesive to both sides of the glass epoxy insulation board using a roller coater and heat it at 100℃ for 1 hour.
The adhesive layer was formed by drying and curing at 160° C. for 5 hours. (This state is shown in FIG. 1.) (3) This substrate was immersed in a chromic anhydride 500 g/1 aqueous solution at 70° C. for 20 minutes, then immersed in a neutralizing solution and washed with water. Next, the adhesive layer was immersed in a 23% hydrofluoric acid aqueous solution for 3.5 minutes at room temperature to remove the fused silica fine powder present on the surface of the adhesive layer, and the surface of the adhesive layer was roughened with the oxidizing agent. Washed with water. (This state is shown in Figure 1.) (4) A photosensitive rubber (manufactured by Hayakawa Rubber Co., Ltd., trade name:
Michelon CSC) was applied by a dip coating method, dried at 80°C for 10 minutes, and then cured with ultraviolet light at 500 mJ/cm ² to form a photosensitive rubber mask on the roughened surface of the adhesive layer. (This state is shown in Figure 1.) (5) Next, through holes were drilled at the required locations. (This state is shown in Figure 1.) (6) After drilling the through holes, the photosensitive rubber was immersed for 5 minutes at 60°C in a stripping solution consisting of 75 g of chromic anhydride, 300 ml of agricultural sulfuric acid, and 700 ml of water. At the same time, the burrs on the adhesive layer around the through holes were also dissolved and removed. (7) Next, a double-sided board was manufactured in the same manner as in Example 1. (This state is shown in Figure 1.) Example 4 (1) 3 parts of acrylonitrile rubber (manufactured by Nippon Zeon Co., Ltd., trade name, Hiker 1072), phenol resin (manufactured by Showa Kobunshi Co., Ltd., trade name, BKPA-5904) 40
Part, epoxy resin (manufactured by Yuka Ciel Co., Ltd., product name,
An adhesive was prepared by mixing 30 parts of Epicoat 1001), diluting with dimethylformamide-butyl cellosolve solvent, and adjusting the viscosity to 500 cps. (2) Apply this adhesive to both sides of the glass epoxy insulation board using a roller coater and heat it at 130℃ for 60 minutes.
The adhesive layer was formed by drying and curing at 150° C. for 3 hours. (This state is shown in Figure 1.) (3) This substrate was mixed with 75 g of chromic anhydride and 300 g of agricultural sulfuric acid.
ml and water for 5 minutes at 60°C to roughen the surface of the adhesive layer with the oxidizing agent, followed by immersion in a neutralizing solution and washing with water.
(This state is shown in FIG. 1.) (4) Thereafter, a double-sided board was manufactured in the same manner as in Example 1. (This state is shown in Figure 1.) Comparative Example 1 (1) Using the same adhesive as in Example 1,
It was applied to both sides of a glass epoxy insulating plate using a roller coater and dried and cured to form an adhesive layer. (This state is shown in Figure 2.) (2) Through holes were drilled at the required locations. (This state is shown in Figure 2.) (3) The substrate with the through holes is coated with 500% chromic anhydride.
The adhesive layer was immersed in a 70° C. g/1 aqueous solution for 20 minutes to roughen the surface with an oxidizing agent, and then immersed in a neutralizing solution and washed with water. (This state is shown in FIG. 2.) (4) Thereafter, a double-sided board was manufactured in the same manner as in Example 1. (This state is shown in FIG. 2.) Various characteristics of the printed wiring board 10 formed by each of the above examples are shown in the following table along with one comparative example. In this table, the pull strength is shown to compare the adhesion of the conductor of the printed wiring board 10 formed, and the insulation of the electroless plating solution, which has an important influence on the characteristics of the through hole 14, is shown. The penetration into the base material 11 (glass cloth) and the surface insulation resistance of the printed wiring board 10 are shown.

[Table] (Effects of the Invention) As detailed above, the method for manufacturing the printed wiring board 10 according to the present invention includes the following steps: A method of manufacturing a printed wiring board 10, which is characterized in that the conductor circuit 16 is formed and the through holes are plated after the following steps are performed. Step of forming adhesive layer 12 on the surface; Step of roughening the surface of adhesive layer 12 with an oxidizing agent; Step of masking the roughened surface with mask material 13; The process of forming holes 14a that will become through holes 14 in the necessary locations of the material 11 and the adhesive layer 12; The process of removing the mask material 13 on the surface. While incorporating a fully additive method suitable for manufacturing wiring boards, it is possible to easily manufacture printed wiring boards having through holes with excellent reliability. A manufacturing method with no material limitations can be provided with a simple configuration. That is, the conventional printed wiring board 10 of this type
In the manufacturing method of the present invention, it is an important condition that the material forming the adhesive layer contains diene rubber, but such a condition does not exist in the manufacturing method of the present invention. be. In other words, in the present invention, the holes 14a that become the through holes 14 formed in the insulating base material 11 are formed after the surface of the adhesive layer 12 is roughened with an oxidizing agent, and During its formation, the roughened surface is the mask material 13
This is because, since the hole 14a is protected by the adhesive layer 12, it will not be adversely affected at all by roughening the adhesive layer 12. Therefore, in the manufacturing method according to the present invention, in order to roughen the adhesive layer 12, it is not an important condition that the material forming the adhesive layer contains diene rubber as in the prior art. It is not. As described above, in the present invention, it is not necessary to use an adhesive containing a diene rubber that is eluted within a short time by chemicals such as oxidation, and therefore the roughening conditions are not changed. Depending on the configuration conditions of the adhesive layer, it can be selected completely arbitrarily. In other words, conventional printed wiring board manufacturing methods that require the use of adhesives containing diene rubber require considerably strict manufacturing conditions when roughening the adhesive containing diene rubber. The temperature of the oxidizing agent must be set to ensure the elution of the oxidizing agent, the immersion time in the oxidizing agent must be strictly controlled,
Strict conditions must be observed, such as setting these conditions according to the amount of diene rubber contained in the adhesive. However, in the present invention, since the presence of an adhesive containing a diene rubber is not a necessary condition, the roughening conditions can be arbitrarily set depending on the adhesive layer. Furthermore, as described above, in the present invention, the holes 14a that will become the through holes 14 formed in the insulating base material 11 are formed after the surface of the adhesive layer 12 is roughened with an oxidizing agent. Therefore, the inside of the hole 14a is not roughened more than necessary at all. Therefore, when the manufacturing method according to the present invention is adopted,
Large irregularities are not formed on the inner wall of the hole 14a, and by directly performing through-hole plating inside the hole 14a, a through-hole 14 with high reliability of conduction can be formed. Furthermore, since the electroless plating solution does not penetrate along the glass cloth or the like that constitutes the insulating base material 11, the insulation resistance between the through holes 14 can be greatly reduced while maintaining sufficient pull strength. There is no such thing. Furthermore, some printed wiring boards cannot be used with adhesives containing diene rubber in order to achieve the unprecedented performance level required for printed wiring boards in recent years, and some adhesives do not contain diene rubber. Although there are cases where it is desired to actively use an agent, the production method according to the present invention is more effective in such cases. Of course, in carrying out the present invention, it is perfectly acceptable to use an adhesive layer containing a diene rubber when the above-mentioned required performance level is not required. According to the manufacturing method of the present invention, the holes 14a that will become the through holes 14 are formed after the roughened surface of the adhesive layer 12 is masked with the mask material 13. It is possible to easily mass-produce highly reliable printed wiring boards 10 without damaging the roughened surface of the agent layer 12.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged cross-sectional view showing a step-by-step process for manufacturing a printed wiring board according to the present invention, and FIG. 2 is a partially enlarged cross-sectional view showing a step-by-step process for manufacturing a conventional printed wiring board. be. Explanation of symbols, 10...Printed wiring board, 11...
... Insulating base material, 12 ... Adhesive layer, 13 ... Mask material, 14 ... Through hole, 14a ... Hole, 14
b...Conductor layer, 15...Catalyst, 16...Conductor circuit.

Claims (1)

[Scope of Claims] 1. A method for manufacturing a printed wiring board in which a desired conductor circuit is formed or through-holes are plated on the surface of a predetermined insulating base material by plating, which includes the following steps: A method of manufacturing a printed wiring board, comprising forming the conductor circuit and plating through holes. Step of forming an adhesive layer on the surface of the insulating base material; Step of roughening the surface of the adhesive layer with an oxidizing agent; Step of masking the roughened surface with a mask material; A step of forming holes to serve as through holes in necessary locations of the insulating base material and adhesive layer; A step of removing the mask material on the surface.