JPH0376599B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for electroless copper plating of printed wiring boards, and in particular to such a method for electroless copper plating of printed wiring boards having a tamping film with excellent mechanical properties. As is well known, most of the printed wiring boards that are widely used in various fields of the electronic industry, from consumer electronic equipment such as radios and televisions to high-end industrial equipment such as computers and information industry electronic equipment, are manufactured using the etched oil method. However, as the electronic equipment industry has advanced to a high level of development in recent years, higher density and higher performance have been promoted. As printed wiring boards become more dense and multilayered, the conventional etched oil method not only deteriorates pattern dimensional accuracy due to undercuts in the etching process and large variations in plating thickness in the electrolytic plating process. , bridges due to overhang, small diameter holes formed in thick boards such as multilayer boards, etc.
When plating a hole with a diameter of approximately 3.2 mm and 1.00 mm or less, there is a large difference in the plating thickness between the corners and the center of the hole. There were drawbacks such as the lack of glazing. For this reason, it is becoming difficult to industrially produce printed wiring boards with high density wiring and high aspect ratios (board thickness/hole diameter). In addition, since the etched oil method uses copper-clad laminates, after the pattern is printed on the copper-clad laminate, the copper foil other than the pattern-printed area must be removed in an etching process, and the waste that is removed during the etching process is Copper foil accounts for 50 to 80% of the total, which is extremely uneconomical, and the etching solution used to remove copper foil is mainly composed of ferric chloride, cupric chloride, or aqueous ammonia. Therefore, if it is accidentally released outside, it can cause pollution problems. In any case, the etched oil method cannot avoid complicating the manufacturing process and wasting copper foil.
It was economically disadvantageous. Therefore, recently, an additive method in which patterns and through holes are formed by electroless copper plating instead of electrolytic plating has been attracting attention. This method can meet the demands for higher functionality, smaller size, higher reliability, and lower cost in electronic devices, and enables industrial production of high-density wiring and high aspect ratio printed wiring boards. I'm getting old. However, according to the conventional electroless copper plating method for printed wiring boards, the substrate to be plated is first degreased using an alkaline solution, then the surface is roughened and activated using acid, etc. An electroless copper plating film with a desired thickness can be obtained by immersing it in an electroless copper plating bath and maintaining it at a constant temperature for a certain period of time. However, the plated films obtained by the above-mentioned conventional methods are generally brittle and are not yet fully satisfactory in practical terms. For example, when electroless copper plating is used to plate conductive patterns and through-holes on a printed wiring board, the plating film is brittle and is strained by mechanical stress that occurs during processing of the printed wiring board and mounting of parts. This has disadvantages such as disconnection of the pattern and corner cracks in the through holes. In contrast, when patterns and through-holes are plated using an electrolytic copper plating method, disconnections, peeling, and cracks in the patterns and corner cracks in the through-holes do not occur as in electroless copper plating. By the way, as a result of measuring the mechanical properties of the plated film obtained by this electrolytic copper plating method, the tensile strength of the plated film was 30 to 50 Kg/mm ² ,
The elongation rate was 3 to 8%, and the number of 180° bending was 4 times. On the other hand, the plated film obtained from an electroless copper plating bath consisting of a copper salt, a complexing agent, a reducing agent, and a PH adjuster is
Tensile strength of ~20Kg/ ^mm2 , elongation rate of about 0.5%,
It was bent about once, and had little reliability as a pattern or through-hole shell for a printed wiring board. Therefore, organic sulfur compounds such as mercaptan, thiol or thio compounds, dipyridyl,
By adding heterocyclic compounds such as phenanthroline and other inorganic cyanide compounds, attempts have been made to improve the mechanical properties of electroless copper plating films. The plated film obtained from such an electroless copper plating bath has mechanical properties such as a tensile strength of 20 to 35 kg/ ^mm2 , an elongation rate of 1 to 2%, and a bending frequency of about 2 times, and is suitable for printing. It is used practically as a copper film for wiring board patterns and through holes. However, copper films for conductive patterns and through-holes of printed wiring boards, which require even higher reliability, require mechanical properties comparable to electrolytic copper plating films. Therefore, attempts have been made to improve the mechanical properties of electroless copper plating films by adding various newly developed or improved ductility improvers to electroless copper plating baths. In addition, by providing an adhesive layer between the plating film and the base,
It was thought that the adhesive layer would play the role of a cushion, relieving distortion caused by mechanical stress that occurs during processing of printed wiring boards and mounting parts, but the adhesion to the electroless copper plating film was very good. Almost no adhesives, adhesives with excellent insulation properties, or adhesives with excellent heat resistance have been found. Moreover, in order to improve the adhesion between the electroless copper plating film and the adhesive, extremely dangerous and harmful acids such as chromium and sulfuric acid mixed acid had to be used. Furthermore, according to the invention described in JP-A No. 57-114657, when forming an electroless copper plating film on the surface of a plated substrate, a copper salt, an acetylating agent, a reducing agent, and a PH adjusting agent are used. The basic composition of the electroless copper plating bath contains an ethylene oxide nonionic surfactant as an additive,
Alternating between an electroless copper plating bath containing at least one of dipyridyl, a phenanthroline derivative, and a cyanide compound and an electroless copper plating bath containing at least one of a sulfur compound, a silicon compound, and a phosphorus compound as an additive. A method is known in which mechanical improvement of an electroless copper plating film is achieved by overlaying an electroless copper plating layer using the above method. However, when applying electroless copper plating to the plated substrate, this method uses only a small amount of additives and the plating bath contains a large amount of interference, so it cannot be analyzed using normal analytical methods. It has the disadvantage that additives must be controlled for each plating bath, which is not possible. The present invention aims to improve the shortcomings of conventional electroless copper plating methods for printed wiring boards, and to provide an electroless copper plating method for printed wiring boards that provides a matted film with excellent mechanical properties. The above object can be achieved by the method described in the claims. That is, the first method of the present invention is an electroless copper plating method performed when manufacturing a printed wiring board, and includes the following steps (a) to (e); that is, (a) a substrate to be plated; , the bath temperature containing several kinds of solutes is
forming a first type electroless plating film on the substrate by immersing it in a first electroless copper plating bath at 50°C or higher; (b) forming a first type electroless copper plating film on the substrate from the first electroless copper plating bath; a step of pulling up the substrate on which the electrolytically plated film has been formed and washing it with water at room temperature; Immersion in a second electroless copper plating bath that contains a solute and has a bath temperature of 50°C or higher, but that is different from the first plating bath in terms of solute concentration and/or bath temperature. a step of depositing and plating a second type electroless plated film different from the first type electroless plated film at a different deposition rate; (d) a plated substrate that has undergone the above step (c); (e) Further, the plating substrate that has undergone the above step (d) is subjected to only the above steps (a) and (b) once. or by repeating steps (a) and (b) of the steps (a) to (d) above two or more times and steps (c) and (d) one or more times. , A layered electroless copper plating film having three or more layers on a substrate, in which adjacent layers are formed at different deposition rates, and each layer has a thickness of 1/100 to 1/2 of the total finished thickness. This is a method for electroless copper plating of printed wiring boards, which is characterized by forming. In addition, the repeated processing in the above steps is to repeat only steps (a) and (b) once (3 layers), or to repeat steps (a) and (d) of each step (a) to (d) above. Step b) is repeated two or more times (five layers or more), and steps (c) and (d) are repeated one or more times (four layers or more) until the desired total thickness is achieved, resulting in three or more layers. This refers to processing to achieve this. Further, the second method of the present invention is a method for electroless copper plating of printed wiring boards, which includes the following steps (a) to (f); namely, (a) a plating substrate containing several kinds of solutes; Bath temperature is 50
a step of forming a first type electroless copper plating film on the substrate by immersing it in a first electroless copper plating bath at a temperature of at least ℃; a step of pulling up the substrate on which the plating film has been formed and washing it with water at room temperature; (c) a step of subjecting the substrate obtained in step (b) above to activation treatment; The plated substrate contains the same kind of solute as that contained in the first plating bath and has a bath temperature of 50°C or higher, but the concentration of the solute and/or the bath temperature is different from that of the first plating bath. A second type electroless plating film different from the first type electroless plating film is deposited at a different deposition rate by immersion in a second electroless copper plating bath having a different temperature. (e) removing the plating substrate that has gone through the step (d) above from the second plating bath and washing it with water at room temperature; (f) further adding On the other hand, repeat only the steps (a) and (b) above once, or repeat steps (a) and (b) of the steps (a) to (e) above two or more times, and ( By repeating steps c), (d), and (e) one or more times, three or more layers are formed on the substrate with each adjacent layer formed at a different deposition rate, and each layer has a thickness relative to the total finished thickness. This is a method for electroless copper plating of printed wiring boards, characterized by forming layered electroless copper plating films each having a thickness of 1/100 to 1/2. Note that the above activation treatment is performed only when transitioning from the first type electroless plating to the second type electroless plating, and prior to the second type electroless plating. Further, the third method of the present invention is a method for electroless copper plating of printed wiring boards, which includes the following steps (a) to (g); that is, (a) a plating substrate is coated with several kinds of solutes. The bath temperature including
forming a first type electroless plating film on the substrate by immersing it in a first electroless copper plating bath at 50°C or higher; (b) forming a first type electroless copper plating film on the substrate from the first electroless copper plating bath; (c) a step of subjecting the substrate obtained in step (b) above to activation treatment; (d) The plated substrate contains the same kind of solute as that contained in the first plating bath and has a bath temperature of 50°C or higher, but the solute concentration and/or bath temperature is lower than that of the first plating bath. A second type electroless plating film different from the first type electroless plating film is deposited at a different deposition rate by immersion in a second electroless copper plating bath different from the first type electroless plating film. (e) removing the plating substrate that has passed through step (d) above from the second plating bath and washing it with water; (f) activating the substrate that has been pulled up through step (e) above; (g) Further, the steps (a) and (b) above are repeated once for the matted substrate that has undergone the step (f) above, or the steps (a) to (f) above are repeated once. By repeating steps (f), (a), and (b) of each step two or more times, and steps (c), (d), and (e) one or more times, on the substrate, To form a layered electroless copper plating film having three or more layers in which adjacent layers are formed at different deposition rates, and each layer has a thickness of 1/100 to 1/2 of the total finished thickness. This is an electroless copper plating method for printed wiring boards, which is characterized by: Note that the above activation treatment is performed before the first type and second type electroless plating treatments. Next, the present invention will be explained in detail. A feature of the present invention is that when forming a pattern with a desired circuit thickness using an electroless copper plating bath, the deposition of electroless copper plating is prevented at least twice with a water washing process in between.
By interrupting the process and forming the electroless copper plating film on the printed wiring board as three or more plating layers, it is possible to reduce the mechanical stress received when parts are mounted on the printed wiring board and when the printed wiring board is used. The purpose of this method is to disperse and reduce strain, and to significantly improve tensile strength, elongation, and number of bends, which are test items for evaluating the mechanical properties of printed wiring boards, compared to conventional electroless copper plating methods. In the present invention, the surface of the substrate is first degreased by dipping or spraying in an organic solvent such as trichloride or an alkaline aqueous solution, then soft etched with acid, and then activated. Electroless copper plating is applied to wiring board substrates. For example, paper-based epoxy resin substrates, synthetic fiber cloth-based epoxy resin substrates, glass cloth-based epoxy resin substrates, paper-based phenolic resin substrates, commercially available catalyst-containing laminates, and catalysts only in the parts that are irradiated with ultraviolet light. The irradiated laminated board containing the substance is immersed in an electroless copper plating bath for a certain period of time to form an electroless copper plating film with a desired plating thickness on the substrate. Thereafter, the plated substrate is removed from the electroless film plating bath for interruption. Next, the pulled up front and rear plated substrates are subjected to activation treatment and other means, and then immersed in the electroless copper plating bath again to perform electroless copper plating to complete the final electroless copper plating process. Repeat until thick. The electroless copper plating film obtained in this way has three or more electroless copper plating layers, so it is not exposed to the mechanical stress that it receives when mounting components on a printed wiring board and when using the printed wiring board. The strain caused by physical stress is dispersed and reduced, and the tensile strength, which is a test item for evaluating the mechanical properties of printed wiring boards, is reduced.
The elongation rate and number of bends can be greatly improved compared to plated films obtained by conventional electroless copper plating methods. In addition, when repeating the operation of immersing a plated substrate in an electroless copper plating bath for a certain period of time, pulling it up, and dipping it into the bath again, the immersion time is changed each time to perform electroless copper plating. There are two options: to apply electroless copper plating or to apply electroless copper plating for the same amount of time, but using the same immersion time for each will improve the tensile strength, The elongation rate and number of bending increases. In addition, when a plated substrate is immersed in an electroless copper plating bath, the thickness of the electroless copper plating film deposited on the substrate in one immersion is The deposition rate is determined by the concentration of each of the four components copper salt, reducing agent, PH adjuster, and complexing agent and the temperature of the electroless copper plating bath. Adjust to 1/100 of the final finished thickness of electroless copper plating.
By setting the tensile strength within the range of ~1/2,
Improves elongation rate and number of bends. Next, in the present invention, electroless copper plating is
When forming more than one layer, the first electroless copper plating bath is treated with a second electroless copper plating bath that differs only in solute concentration and creepage from the first plating bath. It is characterized by using a copper plating bath to perform the plating process, which includes interruptions by dipping and pulling. The specific plating method will be explained below. The two types of electroless copper plating baths used in this case are:
There is no need to change the types of solutes contained in the electroless copper plating bath, especially the types of additives.The types of solutes are the same, and the concentration of each solute in the bath and the temperature of the bath are different. At least one of them is a different bath. When the plated substrate is alternately immersed in two types of electroless copper plating baths, the plated substrate is immersed in the electroless copper plating bath for a certain period of time, and the electroless plating is continued until the desired plating thickness is achieved. After the copper plating has been deposited, the plated substrate is pulled up from the electroless copper plating bath, the pulled up plated substrate is subjected to activation treatment, and then immersed in a different electroless copper plating bath. , repeat until the final finished thickness of electroless copper plating is achieved. The electroless copper plating film obtained in this way has three or more electroless copper plating layers, so it is not exposed to the mechanical stress that it receives when mounting components on a printed wiring board and when using the printed wiring board. The strain caused by physical stress is dispersed and reduced, and the mechanical properties of the printed wiring board, such as tensile strength, elongation rate, and number of bends, are reduced by applying the conventional electroless copper plating method to the electroless copper plating bath. This is greatly improved compared to a plating film that has a non-layered electroless copper plating layer in which the substrate is continuously immersed. A combination of two types of electroless copper plating baths is: (1) a combination of two types of electroless copper plating baths in which the individual solute concentrations in the electroless copper plating baths are the same but the bath temperatures are different; 2)
The concentration of individual solutes in the electroless copper plating bath is different,
A combination of two types of electroless copper plating baths with the same bath temperature; (3) a combination of two types of electroless copper plating baths with different concentrations of individual solutes in the electroless copper plating baths and different bath temperatures; , is. Combinations of the above three types are possible, and in any combination, the plated substrate is continuously immersed in an electroless copper plating bath, and compared to a plated film having a non-layered electroless copper plating layer. , tensile strength, elongation rate, and number of bends are improved. In addition, the thickness of the copper deposited on the surface of the plated substrate when the plated substrate is immersed in each electroless copper plating bath is determined by the final finish of electroless copper plating in one electroless copper plating bath. It is within the range of 1/30 to 1/2 of the thickness, and in the other bath it is 1/100 to 1/30.
It is preferable to set it within the range of. When performing electroless copper plating using a combination of the three types described above, after dipping the plated substrate into one electroless copper plating bath, the plated substrate is pulled out of the electroless copper plating bath, and then a different electroless copper plating bath is applied. When immersing in a copper plating bath, the removed board is washed with water each time, the electroless copper plating solution on the plated board is washed off, and the process of immersing it in a different electroless copper plating bath is repeated. The electrolytic copper plating layer is formed into three or more layers, and the tensile strength, elongation rate, and number of bends are improved. Other methods include applying an activation treatment to the board that is pulled up each time, or rinsing the plated board with water before immersing it in one electroless copper plating bath, and then immersing it in the other electroless copper plating bath. There are three methods of performing activation treatment before dipping, and any of these methods improves tensile strength, elongation, and number of bends. The activation treatment performed on the plated substrate each time it is immersed in an electroless copper plating bath involves washing off the electroless copper plating solution on the plated substrate with water, and then immersing it in an inorganic acid. The copper surface is cleaned by dissolving the oxides and trace amounts of metallic copper that have formed on the copper surface, then the inorganic acid on the plated substrate is washed with water, and the plated substrate is immersed in an electroless copper plating bath. In addition, in the same way as the above method, the electroless copper plating solution adhering to the plated substrate is washed off with water, the copper surface is washed by immersion in an inorganic acid, and then a catalyst is applied, and then the copper plating solution is washed off with water. A method of immersion in an electrolytic copper plating bath is preferred. As mentioned earlier, the inorganic acids used in these two types of activation treatment methods are inorganic acids that can dissolve copper oxides. For example, a simple bath of hydrochloric acid or sulfuric acid or a mixed bath of hydrochloric acid and sulfuric acid is preferred. If the concentration of the inorganic acid is thinner than 0.N, dissolution of copper oxide and metallic copper will hardly occur, and if it is thicker than 10N, the dissolution rate of copper oxide and metallic copper will be negligible even if the acid concentration is increased. Because it does not change,
It is preferably within the range of 0.5 to 10 normal. Further, the temperature of the bath is preferably within the range of 5 to 40°C, and the immersion time of the coated substrate per soak is preferably within the range of 1 to 10 minutes. After the plated substrate is immersed in an electroless copper plating bath for a certain period of time, the plated substrate is pulled out of the electroless copper plating bath and immersed in a different electroless copper plating bath. The activation treatment is preferably performed by washing off the electroless copper plating solution adhering to the plated substrate with water and then applying a catalyst.
No matter which one of the three types, including the above two types, is used, the tensile strength, elongation rate, and number of bends are improved. For catalyst application, an aqueous solution containing metal ions that can serve as a catalyst, such as PdCl ₂ -SnCl ₂ -HCl (colloidal type), is used, and since the working environment is poor due to hydrochloric acid in the bath, this is an improved version. The plated substrate is immersed in any one of the above four types of baths: PDCl ₂ -SnCl ₂ -NaCl (colloid type), palladium organic complex salt compound, and neutral copper type. A liquid capable of adsorbing metal ions and then reducing the metal ions to metals, such as a mixture of sulfuric acid and oxalic acid, a mixture of an alkaline hydroxide such as sodium hydroxide or sodium carbonate, and a borohydride compound. In this method, the substrate on which metal ions have been adsorbed is immersed and the process of reducing the metal ions to metal is repeated at least once, thereby adsorbing the catalyst onto the coated substrate. If the concentration of metal ions in the aqueous solution containing metal ions used in this catalyst application means is less than 20 ppm, the amount of adsorbed metal ions will be small and precipitation of electroless copper plating will not start, and if the concentration is higher than 2500 ppm, metal ions No matter how much the concentration is increased, the amount of metal ions adsorbed remains constant, so 20~
It is preferably within the range of 2500 ppm. Bath temperature is 20℃
If it is lower, the amount of adsorbed metal ions will be small and there will be areas where electroless copper plating will not precipitate, and if it is higher than 60°C, the bath will decompose, so it is preferably within the range of 20 to 60°C. Similarly, regarding the immersion time of the plated substrate once, if it is shorter than 1 minute, the amount of metal ions adsorbed is small and electroless copper plating does not start to deposit; Since the amount of adsorbed metal ions is almost constant, 1~
Preferably within a range of 10 minutes. Next, we will explain the bath temperature, concentration, and immersion time for the reducing solution that reduces metal ions to metals.If the bath temperature is lower than 10℃, the reduction reaction will hardly occur, and if the bath temperature is higher than 50℃, the reducing agent will Since self-decomposition occurs, the temperature is preferably within the range of 10 to 50°C. If the immersion time of the plated substrate is shorter than 2 minutes, the amount of metal ions reduced to metal will be small, and electroless copper plating will not start to be deposited.
Since almost all of the metal ions adsorbed on the substrate are reduced to metal by immersion for about a minute, there is no need for further immersion, and the immersion time is preferably within the range of 2 to 10 minutes. If the concentration of the reducing solution is less than 0.01 mol/min, the reduction reaction to the metal will not occur;
If the concentration is more than 1 mol/mol, the amount will be in excess of the metal ion, and the reduction reaction will be at a nearly constant rate.
It is preferably within the range of 0.01 to 1 mol/. Next, the electroless copper plating bath used in the present invention includes a conventionally used copper salt as a source of cupric ions, a reducing agent for converting copper ions into metallic copper, and an alkaline bath that makes the reducing agent effective. to make a solution
Contains four components: a PH adjuster, a complexing agent to prevent copper precipitation in alkaline solutions, and can also contain other stabilizers if necessary.The function of this stabilizer is Prevents self-decomposition and extends the life of the bath. This longer bath life is due to the masking of the monovalent copper and copper particles by the stabilizer. Stabilizers include chelating agents and polymeric agents, and chelating agents include sodium cyanide, potassium cyanide, potassium cyanide nickel, potassium iron cyanide, potassium cobalt cyanide, dipyridyl, 2(2-pyridyl)imidazone, 2(2-pyridyl)benzimidazole,
1.10-phenanthroline, 2.9-dimethyl-1.10-
Phenanthroline, 4.7-diphenyl-1.10-phenanthroline, 4.7-diphenyl-2.9-dimethyl-1.10-phenanthroline, thiourea, allylthiourea, rhodanine, and 2-mercaptobenzothiazole are known, and are polymeric agents. Known examples include polyethylene glycol and polyethylene oxide. Copper salts include copper sulfate, cupric chloride, copper acetate,
Although copper nitrate or the like can be used, copper sulfate is preferable from the viewpoint of cost. As the reducing agent, hydrazine, formalin, a borohydride compound, and sodium hypophosphite can be used, but formalin is preferable from the viewpoint of cost and stability. Similarly, sodium hydroxide, potassium hydroxide, sodium carbonate, and aqueous ammonia can be used as the pH adjuster, but sodium hydroxide is preferred from the viewpoint of cost. Two kinds of complexing agents can be used: sodium potassium tartrate and sodium ethylenediaminetetraacetic acid salt, but sodium ethylenediaminetetraacetic acid salt is more preferable from the viewpoint of stability of the electroless copper plating bath and high deposition rate. . In the case of copper salt, if the concentration of each of the four components of the electroless copper plating bath is less than 0.01 mol, precipitation will not occur during electroless copper plating, and if it is more than 0.15 mol/concentration, the liquid will not be deposited during electroless copper plating. Since decomposition of the so-called electroless copper plating bath in which copper particles are generated occurs, the amount is preferably within the range of 0.01 to 0.15 mol/. If the reducing agent is thinner than 0.1 mol/mol, the reaction in which divalent copper ions are reduced to metallic copper will not occur;
Since the copper precipitation rate is almost constant at
It is preferably within the range of 0.1 to 1 mol/. The PH adjuster concentration is preferably within the range of 0.1 to 1 mol/, because if it is thinner than 0.1 mol/no precipitation in electroless copper plating will not occur, and if it is thicker than 1 mol//, the electroless copper plating bath will be decomposed. The complexing agent is added to prevent divalent copper ions from reacting with hydroxide to form copper hydroxide precipitates, and its concentration is within the range of 1 to 3 times the molar concentration of copper ions. is preferred. In addition, if the temperature of the electroless copper plating bath is lower than 30°C, the deposition rate is too slow, so it takes too much time to obtain the desired electroless copper plating thickness.
Since decomposition of the electroless copper plating bath occurs at 80°C or higher, the temperature is preferably within the range of 30 to 80°C. The time required to immerse the plated substrate in an electroless copper plating bath for a certain period of time, lift the plated substrate from the plating bath, and immerse the lifted substrate in a different electroless copper plating bath is 45 minutes. Preferably within The reason for this is that if the coated substrate is left in washing water or air for a long time, an oxide film will form on the copper surface, and the adhesion with the copper deposited on this oxide film will deteriorate.
Even thermal distortion to the degree of dryness can cause blistering, so
Preferably within 45 minutes. Using one or two types of electroless copper plating baths, an electroless copper plating layer is formed in a layered manner, and test items such as tensile strength, elongation rate, and bending A method for obtaining an electroless copper plating film with the same number of times as an electrolytic copper plating film was explained in detail. According to another aspect of the method of the present invention, the types of solutes contained in the electroless copper plating bath are the same, and at least one of the concentration of the solute in the bath and the temperature of the bath is different. By sequentially immersing the plated substrate in more than one type of electroless copper plating bath, an electroless copper plating layer can be formed in a layered manner.
It is possible to obtain an electroless copper plating film having tensile strength, elongation rate, and number of bends equivalent to those of the electrolytic copper plating film. The present invention will be explained in more detail with reference to Examples below. Comparative Example 1 A stainless steel plate whose surface was mechanically polished was degreased using a 10 g/aqueous sodium hydroxide solution, and then a catalyst was applied to the surface using an aqueous solution of Cataposi 44 manufactured by Gyplay and Accelerator 19 manufactured by the same company. I did a song. This was used as a covered board. Continuously immersing the plated plate in an electroless copper plating bath having composition 1 listed in Table 1 at a bath temperature of 60°C,
An electroless copper plating film with a thickness of 35 to 40 μm was formed on the plated plate. This plating film was peeled off from the stainless steel plate and cut into pieces of 10 mm in width and 100 mm in length, and the tensile strength and elongation rate were measured using a tensile tester manufactured by Toyo Baldwin. In addition, a bending test was conducted in which another sample was bent 180 degrees and then returned to its original position, and the number of times it took for cracks to occur at the folds was measured. The results are shown in Table 2.

【table】

[Table] In addition, 250 holes with a diameter of 1.00 mm were drilled in a glass cloth-based epoxy resin copper-clad laminate with a size of 100 mm x 100 mm and a thickness of 1.6 mm using a drill. Next, the plated substrate was degreased using an aqueous alkylate solution manufactured by Shipley, smoothed using an aqueous solution of Conditioner 1160 manufactured by Shipley, and the copper surface was roughened using an aqueous solution of ammonium persulfate. Catalysts were applied to the surface using an aqueous solution and Accelerator 19 manufactured by the same company. Using an electroless copper plating bath with the same composition and bath temperature as above, the thickness was 35 to 40 μm by the same method as above.
An electroless copper plating film of m was formed on the plated substrate. The plated substrate obtained by the above method was immersed in a solder bath at 260°C for 10 seconds, left to cool for 5 seconds, and then immersed in room temperature trichloride for 10 seconds.
The minimum number of times a crack occurs at the corner of the hole was measured. The results of this solder dip test are shown in Table 3.

[Table] Comparative Example 2 A stainless steel plate whose surface had been mechanically polished was degreased using a 10 g/aqueous sodium hydroxide solution, washed with water, and neutralized with a 3.6N sulfuric acid aqueous solution. Next, copper sulfate plating is performed, and the thickness is
An electrolytic copper plating film of 35 to 40 μm was formed. This film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, a glass cloth-based epoxy resin-based copper-clad laminate with holes drilled in the same manner as in Comparative Example 1 was degreased using a NutraClean aqueous solution manufactured by Shipley.
The copper surface was roughened using an ammonium persulfate aqueous solution, and then immersed in a 3.6N sulfuric acid aqueous solution to dissolve oxides on the surface. Next, copper sulfate plating was performed to form an electrolytic copper plating film with a thickness of 35 to 40 μm on the plated substrate. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Comparative Example 3 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 1 at a bath temperature of 60°C to form a plated film with a thickness of 2 μm. Next, the plated plate is lifted out of the plating bath, and after washing off the electroless copper plating solution adhering to the plated plate with water, the plated plate is removed from the electroless copper plating bath. A series of immersion operations in a plating bath is repeated to coat the plated plate with a thickness of 35 to 40 μm.
An electroless copper plating film was formed. This plating film was peeled off from the stainless steel plate and Comparative Example 1
The tensile strength, elongation rate, and number of bends were measured in the same manner as above. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using an electroless copper plating bath with a bath temperature of 60℃ and composition 1,
A plating film having a thickness of 35 to 40 μm was formed on the plated substrate by the same plating method as described above. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The result is the third
Shown in the table. Comparative Example 4 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 2 at a bath temperature of 80°C to form a plated film with a thickness of 1 μm. Next, the plated plate is removed from the plating bath, washed with water, and then the plated plate is immersed in the electroless copper plating bath. An electroless copper plating film with a thickness of 35 to 40 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, a catalyst was applied to a glass cloth-based epoxy resin-based copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1 using the same method. Using an electroless copper plating bath with a bath temperature of 80°C and a composition of 2, a plating layer with a thickness of 35 to 30 cm was applied to the plated substrate by the same plating method as described above.
A 40 μm plating film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times cracks occurred at the corner of the hole was measured. The results are shown in Table 3. Example 1 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 2 μm. Next, the plated plate was taken out of the plating bath and washed with water, and then the bath temperature was 60°C and the composition was 8.
The plated plate was immersed in an electroless copper plating bath to form a plated film with a thickness of 0.5 μm. Once again, lift the plated plate out of the plating bath, wash it with water, and then
A series of operations of immersion in an electroless copper plating bath having a composition 7 at a bath temperature of 60 DEG C. were repeated to form an electroless copper plating film with a thickness of 35 to 40 .mu.m on the plated plate. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 7 with a bath temperature of 60°C and composition 8 with a bath temperature of 60°C, a plating method of 35 to 40 μm thick was applied to the plated substrate using the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 2 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 2 μm. Next, the plated plate was taken out of the plating bath and washed with water, and then the bath temperature was 50°C and the composition was 7.
The plated plate is immersed in an electroless copper plating bath of 0.7μ.
A plated film of m was formed. Once again, the plated plate was taken out of the plating bath, washed with water, and then immersed in an electroless copper plating bath of composition 7 at a bath temperature of 60°C.
An electroless copper plating film of 35 to 40 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, one with a bath temperature of 60°C and composition 7, and the other with a bath temperature of 50°C and composition 7, a plating method with a thickness of 35 to 40 μm was applied to the plated substrate using the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 3 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 3 μm. Next, the plated plate was taken out of the plating bath and washed with water, and then the bath temperature was 70°C and the composition was 9.
The plated plate is immersed in an electroless copper plating bath of 0.5μ.
A plated film of m was formed. Once again, the plated plate was taken out of the plating bath, washed with water, and then immersed in an electroless copper plating bath of composition 7 at a bath temperature of 60°C.
An electroless copper plating film of 35 to 40 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. The plated substrate was plated to a thickness of 35 to 40 μm using the same plating method as described above using two types of electroless copper plating baths: composition 7, bath temperature 60 °C, and composition 9, bath temperature 60 °C. A film was formed. Conducting a solder dip test on the plated substrate obtained by the above method,
The minimum number of times a crack occurs at the corner of the hole was measured. The results are shown in Table 3. Example 4 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 4 μm. Next, the plated plate was taken out of the plating bath and washed with water, and then the bath temperature was 70°C and the composition was 8.
The plated plate is immersed in an electroless copper plating bath of 0.8μ.
A plated film of m was formed. Once again, the plated plate was taken out of the plating bath, washed with water, and then immersed in the electroless copper plating bath with composition 7 at a bath temperature of 60°C.
An electroless copper plating film of 30 to 45 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. The plated substrate was plated to a thickness of 35 to 40 μm using the same plating method as described above using two types of electroless copper plating baths: composition 7, bath temperature 60°C, and composition 8, bath temperature 70°C. A film was formed. Conducting a solder dip test on the plated substrate obtained by the above method,
The minimum number of times a crack occurs at the corner of the hole was measured. The results are shown in Table 3. Example 5 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 3 μm. Next, the plated plate was taken out of the plating bath and washed with water, and then the bath temperature was 60°C and the composition was 9.
The plated plate is immersed in an electroless copper plating bath of 0.6μ.
A plated film of m was formed. Once again, the plated plate was taken out of the plating bath, washed with water, and then immersed in an electroless copper plating bath of composition 7 at a bath temperature of 60°C.
An electroless copper plating film of 35 to 40 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 7 with a bath temperature of 60°C and composition 9 with a bath temperature of 60°C, a plate with a thickness of 35 to 40 μm was applied to the plated substrate by the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 6 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having a composition of 8 at a bath temperature of 60°C to form a plated film with a thickness of 2 μm. Next, the plated plate was taken out of the plating bath, washed with water, and the bath temperature was 60°C and the composition was 7.
The plated plate is immersed in an electroless copper plating bath of 0.5μ.
A plated film of m was formed. Once again, the plated plate was taken out of the plating bath, washed with water, and then immersed in an electroless copper plating bath of composition 8 at a bath temperature of 60°C.
An electroless copper plating film of 35 to 40 μm was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 8 and bath temperature 60°C, and composition 7 and bath temperature 60°C, a plating method of 35 to 40 μm thick was applied to the plated substrate using the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 7 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 9 at a bath temperature of 70°C to form a plated film with a thickness of 5 μm. Next, the plated plate was taken out of the plating bath, washed with water, and immersed in a 3.6N sulfuric acid aqueous solution at 30°C for 2 minutes. After washing with water, bath temperature 60
The plated plate was immersed in an electroless copper plating bath having a composition of 8 at a temperature of 8°C to form a plated film of 0.4 μm. The plated plate is lifted from the plating bath, the activation process is repeated once again, and then the plated plate is immersed in an electroless copper plating bath having a composition of 9 and a bath temperature of 70°C. An electroless copper plating film with a thickness of 35 to 40 μm was formed on the plate. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 9 and bath temperature 70°C and composition 8 and bath temperature 60°C, a plating method of 35 to 40 μm thick was applied to the plated substrate using the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 8 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 50°C to form a plated film having a thickness of 2 μm. Next, the plated plate was taken out of the plating bath, washed with water, and immersed in a 1.2N aqueous hydrochloric acid solution at 40°C for 3 minutes. After washing the plated plate with water, it was immersed in a 250 ppm PdCl ₂ -SnCl ₂ -NaCl aqueous solution at 50℃ for 6 minutes, and after washing again with water, each
7 in an aqueous solution containing 0.4 mol/sulfuric acid/oxalic acid.
Soaked for minutes. After washing with water, bath temperature 70℃, composition 9
A plated film with a thickness of 0.5 μm was formed by immersing it in an electroless copper plating bath. The plated plate is removed from the plating bath, the activation process is repeated once more, and then the plated plate is immersed in an electroless copper plating bath having a composition of 7 at a bath temperature of 50°C. An electroless copper plating film with a thickness of 35 to 40 μm was formed on the plate. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 7 with a bath temperature of 50°C and composition 9 with a bath temperature of 70°C, a plate with a thickness of 35 to 40 μm was applied to the plated substrate by the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 9 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 7 at a bath temperature of 60°C to form a plated film with a thickness of 3 μm. Next, the plated plate was taken out of the plating bath, washed with water, and treated with pdCl ₂ − at 250 ppm and 45°C.
It was immersed in a SnCl ₂ -NaCl aqueous solution for 5 minutes. Further washed with water, each containing 0.4 mol/sulfuric acid and oxalic acid.
It was immersed in an aqueous solution at 40°C for 6 minutes. After washing again with water, the plated plate was immersed in an electroless copper plating bath having a composition of 8 at a bath temperature of 70°C to form a plated film with a thickness of 0.6 μm. The plated plate is lifted out of the plating bath, the activation process is repeated once again, and then the plated plate is immersed in an electroless copper plating bath having a composition of 7 at a bath temperature of 60°C. thickness on board
Form an electroless copper plating film of 35 to 40 μm. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 7 and bath temperature 60°C and composition 8 and bath temperature 70°C, a plating method of 35 to 40 μm thick was applied to the plated substrate using the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 10 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having composition 9 at a bath temperature of 70°C to form a plated film with a thickness of 4 μm. Next, the plated plate was taken out of the plating bath, washed with water, immersed in 3.6N sulfuric acid at 30°C for 3 minutes, washed with water, bath temperature 60°C, composition 9.
The plated plate is immersed in an electroless copper plating bath to determine the thickness.
A 0.7 μm plating film was formed. Further, the plated plate was removed from the plating bath, washed with water, and immersed in an electroless copper plating bath having a composition of 9 at a bath temperature of 70°C.
An electroless copper plating film of ~40 μm was formed. Peel off this plating film from the stainless steel plate,
The tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, Comparative Example 1 was applied to a glass cloth base epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1.
Catalyst application was carried out using the same method as described above. Using two types of electroless copper plating baths, composition 9 with a bath temperature of 70°C and composition 9 with a bath temperature of 60°C, a plate with a thickness of 35 to 40 μm was applied to the plated substrate by the same plating method as described above. A coated film was formed. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. Example 11 A catalyst was applied to a stainless steel plate whose surface had been mechanically polished using the same method as in Comparative Example 1. This was used as a covered board. The plated plate was immersed in an electroless copper plating bath having a composition of 8 at a bath temperature of 70°C to form a plated film with a thickness of 2 μm. Next, the plated plate was taken out of the plating bath, washed with water, and immersed in an electroless copper plating bath of composition 9 at a bath temperature of 60°C to form a plated film with a thickness of 0.5 μm. Next, the plated plate was taken out of the plating bath, washed with water, and coated with PdCl ₂ at 250 ppm and 50°C.
The covered plate was immersed in the _-SnCl2 -NaCl aqueous solution for 5 minutes. After washing again with water, the plated plate was immersed for 8 minutes in an aqueous solution at 30°C containing 0.3 mol/0.3 mol of each of sulfuric acid and oxalic acid. After further washing with water, the bath temperature
A series of operations of immersion in an electroless copper plating bath with a composition of 8 at 70°C is repeated, and a thickness of 35~35 mm is applied to the plated plate.
A 40 μm electroless copper plating film was formed. This plating film was peeled off from the stainless steel plate, and the tensile strength, elongation rate, and number of bends were measured in the same manner as in Comparative Example 1. The results are shown in Table 2. In addition, a catalyst was applied to a glass cloth-based epoxy resin copper-clad laminate in which holes were drilled in the same manner as in Comparative Example 1 using the same method as in Comparative Example 1.
Bath temperature 70℃, composition 8 and bath temperature 60℃, composition 9-2
A plating film having a thickness of 35 to 40 μm was formed on the plated substrate by the same plating method as described above using a different type of electroless copper plating bath. A solder dip test was conducted on the plated substrate obtained by the above method, and the minimum number of times a crack would occur at the corner of the hole was measured. The results are shown in Table 3. As is clear from Tables 2 and 3, the electroless copper plating film obtained by the present invention has a tensile strength of 36 to 48 Kg/mm ² , an elongation rate of 3.4 to 5.6%, and a bending frequency of 3 to 4. It has mechanical properties, tensile strength of electrolytic copper plating film is 30 to 50 Kg/mm ² and elongation rate is 3 to 8.
% and the number of times of bending is 4, it can be seen that the values are almost the same. Therefore, according to the method of the present invention, it is possible to obtain an electroless copper plating film having mechanical properties equivalent to those of an electrolytic copper plating film.

Claims (1)

[Claims] 1. In an electroless copper plating method performed when manufacturing a printed wiring board, the following steps (a) to (e); namely, (a) several types of plating substrates are used. The bath temperature containing solute is
forming a first type electroless plating film on the substrate by immersing it in a first electroless copper plating bath at 50°C or higher; (b) forming a first type electroless copper plating film on the substrate from the first electroless copper plating bath; a step of pulling up the substrate on which the electrolytically plated film has been formed and washing it with water at room temperature; Immersion in a second electroless copper plating bath that contains a solute and has a bath temperature of 50°C or higher, but that is different from the first plating bath in terms of solute concentration and/or bath temperature. a step of depositing and plating a second type electroless plated film different from the first type electroless plated film at a different deposition rate; (d) a plated substrate that has undergone the above step (c); (e) Further, the plating substrate that has undergone the above step (d) is subjected to only the above steps (a) and (b) once. or by repeating steps (a) and (b) of the steps (a) to (d) above two or more times and steps (c) and (d) one or more times. , A layered electroless copper plating film having three or more layers on a substrate, in which adjacent layers are formed at different deposition rates, and each layer has a thickness of 1/100 to 1/2 of the total finished thickness. A method for electroless copper plating of a printed wiring board, characterized by forming. 2. The concentration of each solute in the first plating bath is the same as that in the second plating bath,
A method according to claim 1, characterized in that the temperature of the first plating bath is different from that of the second. 3. A patent characterized in that the concentration of each solute in the first plating bath is different from that in the second plating bath, but the temperature of the first plating bath is the same as that of the second plating bath. The method according to claim 1. 4. The concentration of each solute in the first plating bath is different from that in the second plating bath, and
2. The method according to claim 1, wherein the temperature of the second plating bath is also different from that of the second plating bath. 5. The concentration of each solute in the two types of plating baths,
By controlling the temperature of the two types of plating baths and the immersion time in the two types of plating baths, the copper plate deposited on the substrate each time it is immersed in the first plating bath can be controlled. The thickness of the copper plating should be within the range of 1/30 to 1/2 of the final finished copper plating thickness, and the thickness of the copper plating to be deposited on the substrate each time when immersed in the second plating bath should be 2. The method according to claim 1, wherein the plating thickness is within the range of 1/100 to 1/30 of the final finished plating thickness. 6. The method according to claim 1, wherein the two types of electroless copper plating baths contain a copper salt, a reducing agent, a PH adjuster, and a complexing agent as solutes. 7 The copper salts include copper sulfate, cupric chloride, copper acetate,
7. The method according to claim 1, wherein at least one selected from copper nitrate is used. 8 The concentration of copper salt in the two types of plating baths is
The method according to any one of claims 1, 6 and 7, characterized in that the amount is in the range of 0.01 mol/~0.15 mol/. 9. According to claim 1 or 6, the reducing agent is at least one selected from hydrazine, formalin, a borohydride compound, and sodium hypophosphite. Method described. 10 The concentration of the reducing agent in the two types of plating baths is
10. The method according to any one of claims 1, 6, and 9, each in a range of 0.1 mol/ to 1 mol/. 11. According to claim 1 or 6, the PH adjuster is at least one selected from sodium hydroxide, calcium hydroxide, sodium carbonate, and aqueous ammonia. Method described. 12. Claims 1, 6, and 11, characterized in that the concentrations of the PH regulators in the two types of plating baths are each in the range of 0.1 mol/ to 1 mol/.
The method described in any one of paragraphs. 13. The method according to claim 1 or 6, wherein the complexing agent is at least one selected from sodium potassium tartrate and sodium ethylenediaminetetraacetic acid. 14 The molar concentration of the complexing agent in the two types of plating baths is within a range of 1 to 3 times the molar concentration of copper ions in the two types of plating baths. A method according to any one of Ranges 1, 6, and 13. 15 The temperature of the two types of plating baths is 30℃~
15. A method according to any one of claims 1 to 14, characterized in that the temperature is within the range of 80<0>C. 16. Claims 1 to 14, characterized in that the time until the substrate lifted from the first plating bath is immersed in the second plating bath is within 45 minutes. Any one of the methods. 17 In the method for electroless copper plating of printed wiring boards, the following steps (a) to (f) are carried out; namely, (a) the plating substrate is heated to a temperature of 50°C in a bath containing several kinds of solutes.
a step of forming a first type electroless copper plating film on the substrate by immersing it in a first electroless copper plating bath at a temperature of at least ℃; a step of pulling up the substrate on which the plating film has been formed and washing it with water at room temperature; (c) a step of subjecting the substrate obtained in step (b) above to activation treatment; The plated substrate contains the same kind of solute as that contained in the first plating bath and has a bath temperature of 50°C or higher, but the concentration of the solute and/or the bath temperature is different from that of the first plating bath. A second type electroless plating film different from the first type electroless plating film is deposited at a different deposition rate by immersion in a second electroless copper plating bath having a different temperature. (e) removing the plating substrate that has gone through the step (d) above from the second plating bath and washing it with water at room temperature; (f) further adding On the other hand, repeat only the steps (a) and (b) above once, or repeat steps (a) and (b) of the steps (a) to (e) above two or more times, and ( By repeating steps c), (d), and (e) one or more times, three or more layers are formed on the substrate with each adjacent layer formed at a different deposition rate, and each layer has a thickness relative to the total finished thickness. A method for electroless copper plating of a printed wiring board, characterized by forming a layered electroless copper plating film each having a thickness of 1/100 to 1/2. 18. The method according to claim 17, characterized in that the activation treatment method includes performing each of the following steps (a) to (d) one or more times: (a) any one or two of the above steps; (b) immersing the cleaned substrate in a solution consisting of one or more inorganic acids; (c) immersing the immersed substrate in a solution. and (d) cleaning the lifted substrate with water. 19. The method according to claim 17, characterized in that the activation treatment method includes performing each of the following steps (a) to (b) one or more times: (a) any one or both of the above steps; a step of cleaning the substrate taken out of the plating bath with water; and (b) a step of applying a catalyst to the cleaned substrate. 20. The method according to claim 17, characterized in that the activation treatment method includes performing each of the following steps (a) to (e) one or more times: (a) any one or two of the above steps; (b) immersing the cleaned substrate in a solution of one or more inorganic acids; (c) immersed substrate; (d) cleaning the lifted substrate with water; and (e) subjecting the cleaned substrate to activation treatment. 21. The method according to claim 18, wherein the inorganic acid is at least one acid selected from inorganic acids that can dissolve copper oxide. 22. The method according to claim 18, wherein the inorganic acid is at least one acid selected from sulfuric acid and hydrochloric acid. 23 The concentration of the inorganic acid in the solution is 0.5N to 10N
19. A method according to claim 18, characterized in that it is within the scope of. 24 The time for one immersion of the substrate into the solution is:
19. The method according to claim 18, wherein the duration is within the range of 1 minute to 10 minutes. 25. The method of claim 18, wherein the temperature of the solution is within the range of 5°C to 40°C. 26 Claim 19, characterized in that the method for applying the catalyst comprises the following steps (a) to (e):
The method described in Section 1: (a) a step of washing the substrate taken up from any one or two of the above plating baths with water, (b) a step of immersing the substrate in an aqueous solution containing metal ions having a catalytic function. (c) lifting the immersed substrate from the solution; (d) immersing the immersed substrate in a reducing solution capable of reducing metal ions to metal; and (e) lifting the substrate from the reducing solution. . 27 The aqueous solution containing metal ions having a catalytic function is a PdCl ₂ -SnCl ₂ -HCl colloidal aqueous solution,
The method according to claim 26, characterized in that the method is any one selected from a colloidal aqueous solution of PbCl ₂ -SnCl ₂ -NaCl, an aqueous solution of a palladium organic complex salt compound, and a neutral aqueous solution containing copper ions. . 28. The method according to claim 27, wherein the concentration of metal ions having a catalytic function in the aqueous solution is within a range of 20 ppm to 2500 ppm. 29 Claims 26 to 2, characterized in that the temperature of the aqueous solution is within the range of 20°C to 60°C.
The method according to any one of Clause 8. 30 1 of the substrate into the aqueous solution containing metal ions
30. A method according to any one of claims 26 to 29, characterized in that the immersion time for each cycle is in the range of 1 minute to 10 minutes. 31. Claim 26, wherein the reducing liquid is an aqueous solution containing at least one selected from sulfuric acid, oxalic acid, sodium hydroxide, sodium carbonate, and borohydride compounds.
The method described in section. 32 The concentration of solute in the reducing solution is 0.01 mol/
32. The method according to claim 26 or 31, characterized in that the amount is within the range of ~1 mol/. 33. The method according to claim 26 or 31, wherein the temperature of the reducing solution is within a range of 10°C to 50°C. 34 The immersion time of the substrate in the reducing solution is 2 minutes to
32. A method according to claim 26 or 31, characterized in that the duration is within 10 minutes. 35 In the method for electroless copper plating of printed wiring boards, the following steps (a) to (g) are performed; namely, (a) the substrate to be plated is heated to a bath temperature containing several kinds of solutes.
forming a first type electroless plating film on the substrate by immersing it in a first electroless copper plating bath at 50°C or higher; (b) forming a first type electroless copper plating film on the substrate from the first electroless copper plating bath; (c) a step of subjecting the substrate obtained in step (b) above to activation treatment; (d) The plated substrate contains the same kind of solute as that contained in the first plating bath and has a bath temperature of 50°C or higher, but the solute concentration and/or bath temperature is lower than that of the first plating bath. A second type electroless plating film different from the first type electroless plating film is deposited at a different deposition rate by immersion in a second electroless copper plating bath different from the first type electroless plating film. (e) removing the plating substrate that has passed through step (d) above from the second plating bath and washing it with water; (f) activating the substrate that has been pulled up through step (e) above; (g) Further, the steps (a) and (b) above are repeated once for the matted substrate that has undergone the step (f) above, or the steps (a) to (f) above are repeated once. By repeating steps (f), (a), and (b) of each step two or more times, and steps (c), (d), and (e) one or more times, on the substrate, To form a layered electroless copper plating film having three or more layers in which adjacent layers are formed at different deposition rates, and each layer has a thickness of 1/100 to 1/2 of the total finished thickness. A method for electroless copper plating of printed wiring boards, characterized by: 36. The method according to claim 35, characterized in that the activation treatment method consists of repeating the following steps (a) to (d) at least once: (a) Any one of the above. (b) immersing the cleaned substrate in a solution containing one or more inorganic acids; (c) immersing the substrate in a solution containing one or more inorganic acids; and (d) cleaning the lifted substrate with water. 37. The method according to claim 35, characterized in that the activation treatment method includes performing each of the following steps (a) to (b) one or more times: (a) any one or both of the above steps; A step of washing the substrate taken out of the plating bath with water, and (b) a step of applying a catalyst to the cleaned substrate. 38 The method according to claim 35, characterized in that the activation treatment method includes performing each of the following steps (a) to (e) one or more times: (a) any one or two of the above steps; (b) immersing the cleaned substrate in a solution of one or more inorganic acids; (c) immersed substrate; (d) cleaning the lifted substrate with water; and (e) subjecting the cleaned substrate to activation treatment. 39. The method according to claim 36, wherein the inorganic acid is at least one acid selected from inorganic acids that can dissolve copper oxide. 40. The method according to claim 36, wherein the inorganic acid is at least one acid selected from sulfuric acid and hydrochloric acid. 41 The concentration of the inorganic acid in the solution is 0.5N ~
37. A method according to claim 36, characterized in that it is within the range of 10N. 42 The time for one immersion of the substrate into the solution is:
37. A method according to claim 36, characterized in that the duration is within the range of 1 minute to 10 minutes. 43. The method of claim 36, wherein the temperature of the solution is within the range of 5°C to 40°C. 44 Claim 37, characterized in that the method for applying the catalyst comprises the following steps (a) to (e):
The method described in Section 1: (a) a step of washing the substrate taken up from any one or two of the above plating baths with water, (b) a step of immersing the substrate in an aqueous solution containing metal ions having a catalytic function. (c) lifting the immersed substrate from the solution; (d) immersing the immersed substrate in a reducing solution capable of reducing metal ions to metal; and (e) lifting the substrate from the reducing solution. . 45 The aqueous solution containing metal ions having a catalytic function is a PdCl ₂ -SnCl ₂ -HCl colloidal aqueous solution,
The method according to claim 44, wherein the method is any one selected from a PbCl ₂ -SnCl ₂ -NaCl colloidal aqueous solution, an aqueous solution of a palladium organic complex salt compound, and a neutral aqueous solution containing copper ions. . 46. The method according to claim 45, wherein the concentration of metal ions having a catalytic function in the aqueous solution is within a range of 20 ppm to 2500 ppm. 47 Claims 44 to 47, characterized in that the temperature of the aqueous solution is within a range of 20°C to 60°C.
46. The method according to any of paragraphs 46. 48. The method according to any one of claims 44 to 47, wherein the time for one immersion of the substrate in the aqueous solution containing metal ions is within a range of 1 minute to 10 minutes. . 49. Claim 44, wherein the reducing liquid is an aqueous solution containing at least one selected from sulfuric acid, oxalic acid, sodium hydroxide, sodium carbonate, and borohydride compounds.
The method described in section. 50 The concentration of solute in the reducing solution is 0.01 mol/
50. The method according to claim 44 or 49, characterized in that the amount is within the range of ~1 mol/. 51. The method according to claim 44 or 49, wherein the temperature of the reducing solution is within a range of 10°C to 50°C. 52 The immersion time of the substrate in the reducing solution is 2 minutes to
50. A method according to claim 44 or 49, characterized in that the duration is within 10 minutes.