JP2988624B2 - Plating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel plating method suitable for plating an object having fine holes. The present invention has been developed so far in addition to the vibration stirring means and aeration of the plating bath and the swinging means of the plating object which have been known so far.
The present invention relates to a novel continuous plating method using a means for giving a vibration of ６０60 Hz. The plating method of the present invention can be applied to any method of electrolytic plating, a combination of electrolytic plating and electroless plating, and electroless plating.

[0002]

2. Description of the Related Art Printed wiring boards are used as boards for mounting various elements and interconnecting them in all electronic devices from radios, televisions to computers. In the surface mounting method in which components are attached to and connected to the substrate surface, the number of pins has been increased and the pitch has been reduced in recent years, such as a 60-pin / 1.0-mm pitch or a 400-pin / 0.3-mm pitch. After the level, 400 pins /
The technology is steadily progressing to the level of 0.25-0.3 mm pitch and further to the next level.

Accordingly, miniaturization and high performance are required, and fine through holes (through holes) required for wiring between different layers of a laminated substrate and fine holes (blind holes) having a dead-end structure are required. The diameter has been steadily reduced, and has recently been reduced from 0.2 mm or less to 0.05 mm or less, and further to 0.03 mm or less.

[0004] Such micropores cannot easily remove air, dust or processing liquid contained therein, so that the portions where air or dust were present are not plated and are not conductive. Failure to do so, insufficient penetration of the plating solution into the micropores, differences in the thickness of the plating film between the inside and outside of the holes, and the formation of non-plated portions inside the holes, resulting in poor electrical continuity However, there were problems such as a high resistance value.

On the other hand, Japanese Patent Publication No.
Japanese Patent No. 71544 discloses a technique in which a diaphragm in a plating bath has a vibration width of 8 to 20 mm and a vibration frequency of 200 to 600 times /
The invention includes a technique of performing plating by stirring the plating bath by vibrating in minutes, and in particular, claim 3 proposes a combination of aeration and a swinging means of the object to be processed. The inventor of the present application can avoid the occurrence of defective plating in the conventional plating by applying the technique of Japanese Patent Publication No. Hei 6-71544 to the plating of the fine pores of an article having such fine pores. When the method was considered and the method was carried out, the defective rate was certainly reduced, but it was not at a sufficiently satisfactory stage.

Japanese Patent Application Laid-Open No. 62-32690 proposes a method of plating while shaking the object to be plated and applying vibration to the object. The vibration is sent by sending air to a vibrator to vibrate. However, it is not clear what kind of vibration it is, and it is clear that this technique is not very effective in view of the fact that this technique has not been put to practical use at all.

On the other hand, the present inventor repeated the tests in various combinations and conditions by changing the conditions of the vibration stirring, the aeration and the oscillating in various ways. However, no satisfactory results were obtained. When the vibrating means, which was given to the aqueous solution by vibrating stirring as the last remaining means, was also applied to the object to be plated, surprisingly, the reject rate could be drastically reduced, and the present invention was completed. Was.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a fine wiring such as a printed wiring board and an IC board, which is indispensable to 0.2 mm or less, preferably less than 0.1 mm, more preferably 0.05 mm or less. It is an object of the present invention to provide a plating method for reliably and uniformly plating micropores having a diameter of 0.03 mm or less to minimize the occurrence rate of defective products due to incomplete wiring.

[0009]

According to the present invention, there is provided a plating method for sequentially processing an object to be plated from a pretreatment step to a plating step. (A) A vibration generating means including a vibration motor, The vibrating blade fixed in one or multiple stages to a vibrating rod vibrating at 0.5 to 3.0 mm in amplitude and 200 to 200 in frequency
Vibration stirring means for vibrating at 800 times / minute, an inverter for controlling the vibration motor to generate any vibration between 10 and 500 Hz, and a connection between the vibration generation means and the vibration stirring means (B) an aeration apparatus using a ceramic air diffuser having a pore diameter of 200 to 400 μm and a porosity of 30 to 40% as an aeration apparatus for a processing bath provided with a vibration stress dispersing means; ) A swinging device for giving a swinging width of 10 to 100 mm and a swinging speed of 10 to 30 times / min through an electrode bar on which the object to be plated is suspended. (D) The object to be plated is suspended. Via the lowering electrode bar, using a vibration motor adjusted to 10 to 60 Hz by an inverter, an amplitude of 0.5 to 1.0 mm and a frequency of 10
A continuous device characterized by operating a vibrating device for giving a vibration of 0 to 300 times / min in at least a cleaning tank, an electroless plating tank and / or an electrolytic plating tank in a pretreatment step for plating and a plating step. It relates to a plating method.

The vibration stirring device for the treatment bath of the above (A) in the present invention includes a vibration generating means including a vibration motor, and a vibrating blade fixed in one or more stages to a vibrating rod vibrating in a stirring tank in cooperation therewith. 0.5-3.0m amplitude
m, vibration stirrer for vibrating at a frequency of 200 to 800 times / minute, and any vibration of the vibration motor between 10 and 500 Hz, preferably 30 to 60 Hz, more preferably 30 to 40 Hz. It is preferable that an inverter for controlling the vibration generation means and a vibration stress dispersing means be provided at a connection between the vibration generating means and the vibration stirring means.

Although there is no particular limitation on the aeration apparatus for the treatment bath, a diffuser tube is provided so that the portion where the object to be plated is present can be sufficiently stirred by air bubbles. In the case of a diffuser tube having a large number of pores with a pore diameter of about 1 mm in a synthetic resin pipe such as PVC, air particles are too large, so that effective removal of electrolytic heat cannot be performed, and variations in electric resistance have occurred. However, the aeration apparatus used in the present invention has solved the above-mentioned problem by using a ceramic porous tube as the air diffuser. As the ceramic porous tube, a high-temperature fired ceramic tube made of alumina grain such as Alundum as an aggregate is preferable, and the pore diameter of the diffuser tube is preferably 200 to 400 μm, and the porosity (surface area) 30 to 4)
About 0% is preferable. The outer diameter of the diffuser is usually 50-100
mm, and the length is usually about 100 to 200 mm, although it depends on the length of the processing tank. There is no particular limitation on the installation method, but when using multiple tubes, attach a diffuser tube so as to sandwich the object to be plated. The distance between the air diffusers is preferably 100 to 200 mm. The vertical interval between the air diffuser and the object to be plated is usually preferably 100 to 300 mm.

The swing given by the object to be plated through the suspended electrode bar is preferably a swing width of 10 to 100 mm, preferably 20 to 60 mm, and a swing frequency of about 10 to 30 times / min.

The number of Hz of the vibration motor for applying vibration to the electrode bar is preferably 50 to 65% with respect to the number of Hz of the vibration motor of (A), and the number of Hz is preferably 10 to 60 Hz. Is 20-35 Hz and the amplitude is 0.5-1.0 mm. This vibration causes the object to be plated to vibrate, but does not give a flow to the processing liquid.

The plating method of the present invention is extremely useful as a method for plating a laminate having a plastic surface such as a printed wiring board or an IC board having a fine hole, particularly an article having a fine hole. Especially the micropores are 0.2mm or less,
Preferably less than 0.1 mm, more preferably 0.05
mm or less, even more preferably a printed wiring board, an IC board having fine holes having a diameter of 0.03 mm or less,
It is very useful for plating metal plates and plastic plates. Note that examples of the electroless plating and / or electrolytic plating in the present invention include copper plating, nickel plating,
Silver plating, tin plating, gold plating, palladium plating,
Examples include solder plating.

In the present invention, the pretreatment includes pickling, degreasing, and pretreatment of each object to be plated as described in “Plating Technique Handbook”, pages 117 to 148, published by Nikkan Kogyo Shimbun on July 25, 1971. And cleaning, etching, catalysis, chemical plating, activation, and pretreatment of plastics such as copper strike as described on pages 655 to 665. The plating process includes various electroplating processes and electroless processes. It also includes a plating step.

In the present invention, (A), (B), (C),
The apparatus (D) is used in at least all of the main steps of the continuous plating method, but is preferably used in all of the steps.

(Advantage of Use of Apparatus A) During the electrolysis of the plating solution, hydrogen gas is generated on the cathode surface (object to be processed) to form fine bubbles in the solution, and the bubbles cover the entire surface of the object to be processed. Covering, increasing the electrical resistance, reducing the plating rate, and further impairing the throwing power. However, by giving the flow generated by the low-frequency vibration to the processing liquid as described above,
The surface tension in the liquid can be significantly reduced,
As a result, most of the gas generated on the surface of the object is discharged out of the system as it is. As a result, the current distribution becomes more uniform and the electric resistance decreases, so that more uniform electrodeposition can be obtained at several times higher speed than in the prior art.

In the case where the micropores of the object to be plated have a very fine size such as 20 to 50 μm, the intended purpose can be largely achieved only by the above-mentioned flow caused by vibration unless the processing time is lengthened. It is very difficult. Therefore, by applying a vibration of 10 to 60 Hz, preferably 20 to 35 Hz to the object to be plated and simultaneously giving the object to be oscillated at a level of 10 to 30 times / min, the fine holes can be formed in a very short time. The flow of the processing liquid to the processing liquid is averaged.

According to the present invention, the use of an air diffuser allows a large amount of fine bubbles to be generated to rise around the object to be plated and to be discharged out of the treatment bath. (Joule heat) effectively cools the object to be plated quickly, and effectively removes air and dust removed from the fine holes of the object to be plated. Plating can be performed uniformly without generating kogation.

In the treatment solution, especially in the plating solution, the boundary layer which is easily formed between the plated layer and the plating bath is very easily destroyed by the combined use of the means A, B, C and D. In addition, the supply of the processing bath to the surface of the object to be plated becomes extremely smooth, which greatly contributes to uniform processing, smoothing of the plating surface, and good gloss.

A typical process in continuous plating of a printed wiring board is as follows. (Following the plastic plating process) ○ Cleaning → Rinsing → Etching → Rinsing → ○ Catalysis →
Rinsing → ○ electroless copper plating → water washing → sulfuric acid washing → ○ copper sulfate plating → water washing → (drying) In each of these steps, each water washing step is often performed in two tanks, and electroless plating and electroplating are also performed in two steps. It is often done in tanks. To easily perform continuous plating,
It is easiest to use a system that lifts the object to be plated after a certain period of time and moves it to the next tank. As long as the number of the processing tanks is the same, the processing time will be the same. Therefore, the processing time can be extended by using two or more tanks that require long-time processing. In addition, in order to complete the removal of the adhering liquid in the previous step as in the case of washing with water, it is better to change the tank so that the washing efficiency is higher. From this point of view, it is significant to use a plurality of washing tanks. In such a continuous plating step, the apparatus of (A) to (D) of the present invention includes at least the ○
It is used in the marked step, but is more preferably used in all steps except the washing step, and preferably in all steps including the washing step.

The cleaning step can be a so-called degreasing step or a step for swelling plastics in addition to degreasing.

In the etching process, irregularities were mechanically formed on the surface by sandblasting or a liquid honing method in the past, but recently, irregularities are generally formed by chemical treatment using a chemical solution. For example, this is a step of forming irregularities on the surface of plastics using a mixed solution of sulfuric acid-chromic acid, a mineral acid, and a concentrated alkali solution.

In the catalyzing step, a catalyst layer such as palladium is planted on the surface after etching, and the preparation of the electroless plating is carried out. The catalyzing method includes a sensitizing → activating method and a catalytic method. Rising → accelerating method or the like is used. In the former, plastics are immersed in a tin ion solution with strong reducing power to deposit tin on the surface, and then immersed in a palladium ion solution having catalytic activity to cause a redox reaction on the plastic surface and fix the catalyst layer. In the latter method, the plastics is immersed in a solution in which tin ions and palladium ions are mixed, and the colloidal palladium-tin or palladium-tin complex compound is deposited on the surface, and then tin is removed. It is a method of activating palladium (published by Dai Nippon Tosho Co., Ltd., September 20, 1992, edited by The Chemical Society of Japan, “Chemistry for 100 Million People, II Plating and High Tech”, pp. 92-97).

FIGS. 1 to 3 show specific examples in which the devices (A), (B), (C) and (D) are installed in the pretreatment tank and the plating tank in the present invention. FIG. 1 is a plan view and FIG.
Is a front view, and FIG. 3 is a side view thereof. Only the portion of the vibration stirrer including the vibration motor 4 shown in FIGS. 1 to 3 is shown in a sectional view in FIGS. FIG.
3 is a sectional view taken along line XX of FIG. 2, and FIG. 5 is a sectional view taken along line YY of FIG.

In FIGS. 1 to 3, the aeration apparatus (B) is shown by two air diffusers 12, 12, and a compressed air inlet 10 for sending compressed air thereto.

In FIGS. 1 to 3, the rocking device includes a rocking motor 3, a rocking receiving frame 2 which is rocked by the movement of the rocking motor, and a cathode-and-suspension fixed to the rocking receiving frame 2 by a cathode rod receiver 13. A hanging tool 5 is provided, and the object to be plated is firmly connected and fixed both electrically and physically to the cathode and hanging tool 5.

Then, in order to apply vibration to the swing receiving frame 2, a vibration motor 14 is fixed to an appropriate portion of the swing receiving frame, and the vibration of the vibration motor 14 causes the swing receiving frame 2 to vibrate, which is an IC substrate or the like. The mechanism is transmitted to the object to be plated. The rocking at this time is such that the rocking is slowly performed at a rate of 10 to 30 times / minute with an amplitude of 10 to 60 mm, preferably 20 to 50 mm.

In this specific example, the swing direction is the left-right direction in FIGS. 1 and 2, but the swing of the swing receiving frame 2 has an amplitude of 0.5 to 1.0 mm. Vibration motor is 10-60Hz by inverter,
Preferably, a vibration of 20 to 35 Hz is generated.

An example of a vibration stirrer for a bath is shown in FIG.
As shown in FIG. 5, the vibration stirrer itself is not limited to this example.
No. 1, JP-A-6-312124, JP-A-6-3303
No. 95, JP-A-8-173785, JP-A-9-404
No. 82 and Japanese Patent Publication No. 6-71544 can be used.

The vibration stress dispersing means is, for example, a rubber ring provided around the vibrating rod at the connection between the vibration generating device and the vibrating rod, and the length thereof is longer than the diameter of the vibrating rod. Preferably, the diameter is 3 to 8 times the diameter of the rod and the thickness is 1.3 to 3.0 times, especially about 1.5 to 2.5 times larger than the diameter of the vibrating rod. From another viewpoint, when the diameter of the vibrating bar is a round bar having a diameter of 10 to 16 mm, the thickness of the rubber ring is preferably 10 to 15 mm, and when the diameter of the vibrating bar (round bar) is 20 to 25 mm. Is
The thickness of the rubber ring is preferably 20 to 30 mm. In the case where the rubber ring is not used, there is a problem that the vibration stress is concentrated near the joint between the vibration transmitting member and the vibration bar, and the vibration bar is easily broken. Can be completely eliminated.

The vibrating blade can be preferably made of a thin metal, a resilient synthetic resin, rubber, or the like. The thickness of the vibrating blade is such that at least the tip of the blade is fluttered by the vertical vibration of the vibrating motor. (Wave-like state), so that a flow can be given to the system in addition to the vibration. Titanium, aluminum, copper, steel, stainless steel, and alloys thereof can be used as the material of the metal vibrating blade. As the synthetic resin, polycarbonate, vinyl chloride resin, polypropylene and the like can be used. The thickness is not particularly limited in order to increase the effect of vibration by transmitting vibration energy, but generally 0.2 to 2 mm for metal and 0.5 to 10 mm for plastic. If the thickness is excessively large, the effect of the vibration stirring decreases.

When an elastic synthetic resin, rubber or the like is used as the material of the vibrating blade plate, the thickness is not particularly limited, but is generally preferably 1 to 5 mm. It is preferably 0.5 mm. The amplitude of the diaphragm is 2 to 30 mm,
Preferably it is 5 to 10 mm.

The vibrating blade can be attached to the vibrating shaft in one or more stages. A plurality of vibrating blades can be used according to the depth of the processing liquid. When the number of stages is increased, if the load of the vibration motor is increased, the vibration width decreases, and the vibration motor may generate heat.

The vibrating blades may be all mounted at right angles to the vibrating bar, but when the perpendicular direction of the vibrating bar is 0 °, it is preferably 5 to 30 ° in the (+) or (−) direction. Is preferably installed at an angle of 10 to 20 ° (see FIGS. 4 and 6). Further, the vibrating blade fixing member and the vibrating blade can be integrally inclined and / or bent as viewed from the side surface of the vibrating shaft. Even if it is curved, it is preferable to have an inclination of 5 to 30 degrees, particularly 10 to 20 degrees as a whole.

The vibrating blade can be formed by sandwiching the vibrating blade from both upper and lower surfaces with a vibrating blade fixing member and fixing it to the vibrating rod. Specifically, the vibrating blade may be threaded on the vibrating rod and fixed by tightening with a screw. However, as shown in FIG. 6, the vibrating blade 17 is assisted so as to clamp the vibrating blade 17 from above and below. The vibration blades 1 and 18 are held down by using fixing members 18 and 18 and the vibration blade fixing members 18 and 18 are tightened with screws 24 and 24.
7 is preferably fixed.

When the vibrating blades are inclined and / or curved, the lower ones among a number of vibrating blades.
Two may have a downward slope and / or curvature, and the other may have an upward slope and / or curvature. In this case, the stirring at the bottom of the stirring tank can be sufficiently performed, and the formation of the pool at the lower portion can be prevented.

If it is not desired to agitate only the bottom of the stirring tank, it can be dealt with by removing the downwardly curved vibrating blade. For example, it is convenient to collect unnecessary components such as precipitates in the lower portion and take out the unnecessary components from the lower portion without diffusing them.

The vibration stirrer may be provided only at one end of the processing tank as shown in FIGS. 9 and 10. However, by providing it at both ends of the processing tank as shown in FIGS. it can. In addition, as the vibrating stirrer shown in the figures, any type of vibrating the vibrating blade vertically is shown.
As shown in Japanese Patent No. 04461 and FIGS. 7 and 8, there is a method in which the vibration direction is set to the horizontal direction and the vibration blade 17 is attached to the bottom of the processing tank 1. In this case, in order to balance the left weight and the right weight centering on the vibration motor 27 installed on the left side in FIG. 8, it is preferable to provide the balancer 26 having a weight balanced with the left weight.

The vibrating rod can be used by directly connecting to a vibrating motor.
As described in Japanese Patent Application No. 304461 or Japanese Patent Application Laid-Open No. 6-330395, a method in which vibration of a vibration motor is transmitted to a vibration rod via a vibration frame may be adopted.

The vibrating blade 17 and the vibrating blade fixing member 1
8 and 18 between the fluoropolymer films 23 and 23
Is preferable because the breakage rate of the vibrating blade is greatly reduced. As the fluorine-based polymer, polytetrafluoroethylene (PTFF), tetrafluoroethylene /
Hexafluoropropylene copolymer (FEP), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVD)
F), polyvinyl fluoride, ethylene / tetrafluoroethylene copolymer (ETFE), ethylene / chlorotrifluoroethylene copolymer, propylene / tetrafluoroethylene copolymer, and the like. Are preferred.

[0042]

The present invention will be described below with reference to examples.
The present invention is not limited thereby.

Example 1 As shown in FIGS. 1 to 5, (A) a vibration stirrer
(B) an aeration device, (C) a device for giving a swing to a hanging object of the plating object, and (D) a device for giving a vibration to the object to be plated through the hanging device, and under the following conditions, Pretreatment and plating were performed.

(1) Plated object: 34 having a thickness of 0.5 mm
The diameters of the fine through holes provided in the glass epoxy copper-clad laminate of 0 × 340 mm are the following four types: 0.5 mm 0.2 mm 0.1 mm 0.05 mm

(2) Arrangement of treatment tank Degreasing tank (○) → hot water tank → water washing tank → water washing tank → etching tank → water washing tank → water washing tank → first catalyst tank (○) → second catalyst tank (○) → Rinse tank → Rinse tank → Accelerator tank (○) → Rinse tank → Rinse tank → Electroless copper plating tank (○) → Electroless copper plating tank (○) → Rinse tank → Rinse tank → Sulfuric acid tank → Copper sulfate plating tank (O) → Copper sulfate plating tank (O) → Rinse tank → Rinse tank → Dry tank, treatment time is 5 minutes, current density is 2 A / dm ²
And The four devices (A) to (D) were attached to the tanks marked with ○.

(3) Vibration stirrer: Vibration motor: 250 W × 200 V × 3 phase Vibration blade: Effective area 300 × 150 mm, thickness 0.6 mm, 6 sheets, α = 15 ° (all upwards) Amplitude: 1.5mm Vibration frequency: 40Hz (adjusted by inverter)

(4) Aeration apparatus Two ceramic air diffusers having an outer diameter of 75 mm, an inner diameter of 50 mm, a length of 500 mm, and a pore diameter of about 200 μm were used. 40% porosity per tube, about 40 liters of air per minute

(5) Swinging device 20 times by gear motor or cylinder motor /
Give a swing of 40 mm back and forth in minutes.

(6) Vibration Device Attached to Swing Device A vibration motor (40 W) 14 is provided at an appropriate position of the swing receiving frame 2.
And fix the vibration motor 14 via the inverter.
Vibration is performed at 0 Hz and amplitude of 0.8 mm.

(7) Degreasing bath (tank size: 450 × 350)
× 650 mm, width × length × height) sodium carbonate 40 g / l sodium tertiary phosphate 20 g / l sodium hydroxide 5 g / l surfactant 1 g / l bath temperature and time 60 ° C., 5 minutes

(8) Etching bath (tank size: 450 × 180 × 650) Sulfuric acid (sg 1.84) 500 ml / liter phosphoric acid (sg 1.74) 100 ml / liter anhydrous Chromic acid 30g / liter Bath temperature and time 65 ℃, 10 minutes

(9) First catalyst bath (inner size of tank: 450 × 2
00 × 650) Stannous chloride 10 g / l Concentrated hydrochloric acid 40 ml / l Bath temperature and time Room temperature, 5 minutes

(10) Second catalyst bath (tank size: 450 ×
350 × 650) Palladium chloride 0.1 g / L Hydrochloric acid 1 mL / L Bath temperature and time Room temperature, 5 minutes

(11) Accelerator bath (inside of tank:
450 × 180 × 650) Sulfuric acid 75 ml / liter Bath temperature and time 50 ° C., 5 minutes

[0055] (12) an electroless copper sulfate plating bath (inner tank dimensions: 450 × 350 × 650) Copper sulfate _{(CuSO 4 · 5H 2 O)} 10g / l Rochelle salt _{(KNaC 4 H 4 O 6 ·} 4H 2 O 35 g / l sodium hydroxide 8 g / l formalin (37%) 20 g / l stabilizer small amount PH 12.5-13 bath temperature and time 40 ° C, 10 minutes

(13) Copper sulfate plating bath (tank size: 450 × 450 × 650) Copper sulfate (CuSO ₄ .5H ₂ O) 75 g / l Sulfuric acid 190 g / l Conductivity imparting agent 50 mg / l Brightener 5 ml The plating treatment was performed under the conditions of bath temperature and time of 40 ° C. for 10 minutes or more. The results are shown in Table 1.

Comparative Example 1 Only the aeration device of (B) and the swinging device of (C) were installed, and the object to be plated of Example 1 was subjected to plating using the baths of Example 1. Table 1 shows the results.

COMPARATIVE EXAMPLE 2 A vibrating device for the aeration device (B), the oscillating device (C), and the oscillating device (D) was installed. Plating was performed using each bath. Table 1 shows the results.

Comparative Example 3 The vibration stirrer of (A), the aeration device of (B) and the rocking device of (C) were set, and
Was plated using the baths of Example 1. Table 1 shows the results.

[0060]

[Table 1] * 1 The maximum current density refers to the highest current density at which no burn marks are generated, with the current density gradually increasing. * 2 (Average plating thickness at the center of the through hole) ÷ (Average plating thickness at the flat portion of the substrate) × 100 * 3 × indicates that no plating is performed in the through hole. * 4 σ indicates the standard deviation of variations in plating thickness. * 5 The gas pit defect rate (%) is determined by a method of finding defective products by attaching gas etc. to a test product that has passed the plating continuity test by a visual inspection using a magnifying glass and an X-ray inspection to find defective products. Was.

Example 2 The arrangement of each device of (A), (B), (C) and (D) was the same as that of Example 1, but the arrangement of the processing tank was changed as follows, and nickel plating was performed. Was done. Current density is 2
A / dm ² .

(1) Arrangement of treatment tank Swelling tank (（) → water washing tank → etching tank (○) → water washing tank →
Neutralization tank → Rinse tank → Catalyst tank → Rinse tank → Accelerator tank →
Rinse tank → Electroless nickel plating tank (○) → Rinse tank → Activation tank → Rinse tank → Strike plating tank → Rinse tank → Copper sulfate plating tank → Rinse tank → Nickel plating tank → Rinse tank ○ Four devices (A) to (D) were installed.

(2) Swelling bath sodium carbonate 90 g / l sodium tertiary phosphate 20 g / l sodium hydroxide 5 g / l surfactant 1 g / l water-soluble solvent 80 g / l bath temperature and time 5 minutes at 80 ° C.

(3) Etching bath Chromic acid 400 g / l Sulfuric acid 400 g / l Bath temperature and time 5 minutes at 65 ° C.

(4) Neutralization bath hydrochloric acid 50 ml / liter

(5) Catalyst bath Palladium chloride 0.2 g / L Stannous chloride 20 g / L Concentrated hydrochloric acid 200 mL / L Bath temperature and time 5 minutes at room temperature

(6) Accelerator bath Sulfuric acid 100 ml / liter Bath temperature and time 5 minutes at 50 ° C.

(7) Electroless nickel plating bath Nickel sulfate 30 g / l Sodium hypophosphite 20 g / l Ammonium citrate 50 g / l Bath temperature and time 10 minutes at 40 ° C.

(8) Activation bath Sulfuric acid 50 g / l Bath temperature and time 1 minute at room temperature

(9) Strike plating bath Nickel sulfate 200 g / l Nickel chloride 40 g / l Boric acid 40 g / l Bath temperature and time 5 minutes at 50 ° C.

[0071] (10) copper sulfate plating bath Copper sulfate _{(CuSO 4 · 5H 2 O)} 75g / l sulfuric acid 190 g / liter conductive agent 50 g / l Bath temperature and 10 minutes at time 40 ° C.

(11) Nickel plating bath Nickel sulfate 200 g / L Nickel chloride 40 g / L Boric acid 30 g / L Brightener Small amount Bath temperature and time 10 minutes at 50 ° C.

Comparative Example 4 Only the aeration device (B) and the rocking device (C) were installed, and the object to be plated in Example 2 was plated using each bath in Example 2. Table 2 shows the results.

Comparative Example 5 A vibrating device for the aeration device (B), the rocking device (C), and the rocking device (D) was installed. Plating was performed using each bath. Table 2 shows the results.

COMPARATIVE EXAMPLE 6 The vibration stirrer (A), the aeration device (B) and the rocking device (C) were set up, and
Was plated using the baths of Example 2. Table 2 shows the results.

[0076]

[Table 2] * 1 The maximum current density refers to the highest current density at which no burn marks are generated, with the current density gradually increasing. * 2 (Average plating thickness at the center of the through hole) ÷ (Average plating thickness at the flat portion of the substrate) × 100 * 3 × indicates that no plating is performed in the through hole. * 4 σ indicates the standard deviation of variations in plating thickness. * 5 The gas pit defect rate (%) is determined by a method of finding defective products by attaching gas etc. to a test product that has passed the plating continuity test by a visual inspection using a magnifying glass and an X-ray inspection to find defective products. Was.

Example 3 Example 1 was repeated except that the thickness of the printed wiring board was 0.8 mm and the diameter of the through hole was 0.1 mm. In this case, the thickness was 1.6 times that of Example 1, And (thickness) ÷ (diameter) = 0.8 ÷ 0.1 = 8, that is, the actual condition under an extremely high aspect ratio condition of an aspect ratio of 8. Table 3 shows the results.

Comparative Example 7 As described above, Comparative Example 1 was performed except that the aspect ratio was set to 8.
The same processing as described above was repeated for the printed wiring board of Example 3. Table 3 shows the results.

Comparative Example 8 As described above, Comparative Example 2 was conducted except that the aspect ratio was set to 8.
The same processing as described above was repeated for the printed wiring board of Example 3. Table 3 shows the results.

Comparative Example 9 As described above, Comparative Example 3 was performed except that the aspect ratio was set to 8.
The same processing as described above was repeated for the printed wiring board of Example 3. Table 3 shows the results.

[0081]

[Table 3]

As described above, when the data of Tables 1 to 3 are combined,
Compared to the case where only the devices B and C are used together, the devices B, C and
When D is used or when the devices A, B, and C are used in combination, some improvement is recognized in the throwing power of the through-hole and the standard deviation of the variation of the plating thickness. However, in the case of the present invention in which the four devices A, B, C, and D are used in combination, it is shown that the throwing power, the standard deviation, and the gas pit defect rate of the plating of the through hole are dramatically improved. The remarkable effect is shown in Comparative Example 2.
And 3 and Example 1; and Comparative Examples 5 and 6 and Example 2 and Comparative Examples 8 and 9 and Example 3 which are clear.

Example 4 The apparatus shown in FIGS. 9 to 11 was used.

Plated object Two glass epoxy copper-clad laminates having a size of A4 size having a thickness of 8 mm and having fine through holes having a diameter of 0.05 mm were suspended in parallel and plated.

The same vibration stirrer as in Example 1 was used.

The aeration apparatus is a diffuser tube 2 having an outer diameter of 75 mm, an inner diameter of 50 mm, a pore diameter of 200 μm, and a porosity of 40%.
A book was used.

The rocking device provided rocking at a rate of ± 15 mm at 20 times / minute.

1. Degreasing / swelling process (using Enplate MLB-496 (trade name) containing a water-soluble solvent composed of ethyl cellosolve and an alkali component) Inner size of tank: 180 x 750 x 500 mm (width x length x height) Processing conditions: (A ), (B), (C), and (D) were operated for 5 minutes at 60 ° C. 2. Rinsing step Treatment conditions: The apparatus of (B) was operated and rinsed at room temperature for 5 minutes. 3. Etching process (using Enplate MLB-497 (trade name containing potassium permanganate)) Internal size of tank: 180 × 450 × 500 Processing conditions: Four devices of (A), (B), (C), and (D) And treated at 70 ° C. for 5 to 10 minutes. 4. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 5. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 6. Reduction process (brand name enplate ML including H ₂ SO ₄₎
B-791) Inside size of tank: 180 × 450 × 500 Processing conditions: Processing at 60 ° C. for 5 minutes by operating four devices (A), (B), (C) and (D). 7. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 8. Conditioner process (using Melplate PC-321 containing a surfactant) (trade name) Inside size of tank: 180 × 450 × 500 Processing condition: Treated at 60 ° C. for 5 minutes by operating apparatus (B). 9. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 10. Micro-etching step (using Melplate AD-331 containing trade name of persulfate) Inner size of tank: 180 × 450 × 500 Processing condition: Processing at 65 ° C. for 5 minutes by operating the apparatus of (B). 11. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 12. Dilute sulfuric acid washing step (10% H ₂ SO ₄ ) Internal size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated and processed at room temperature for 5 minutes. 13. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 14． Pre-dipping process (using Enplate PC-236 containing chlorate) Inner size of tank: 180 × 450 × 500 Processing condition: Processed at room temperature for 5 minutes by operating the apparatus of (B). 15. Activation Step (Use of Enplate Activator 444 (trade name) which is a colloid solution containing Sn and Pd ions) Inner size of tank: 180 × 450 × 500 Treatment conditions: 5 ° C. at room temperature by operating the apparatus of (B) Minute processing. 16. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 17． Acceleration step (using Melplate PA-360 containing a surfactant containing a surfactant) Inner size of tank: 180 × 450 × 500 Processing condition: Treatment was performed at room temperature for 5 minutes by operating the apparatus of (B). 18. Rinsing step Inner size of tank: 180 × 450 × 500 Processing condition: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 19. Electroless copper plating step (using Melplate Cu-390, trade name according to the composition of Example 1) Inner size of tank: 180 × 750 × 500 Processing conditions: (A), (B), (C), (D ), And operated at room temperature for 20 minutes. 20. Rinsing step Inner size of tank: 180 × 750 × 500 Processing conditions: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. 21. Dilute sulfuric acid washing step (10% H ₂ SO ₄ ) Inner size of tank: 180 × 750 × 500 Treatment condition: 1 minute treatment at room temperature. 22. Electroplating step (copper plating bath according to the composition of Example 1) Inner size of tank: 180 × 750 × 500 Processing conditions: Four devices of (A), (B), (C) and (D) are operated And treated at 30 ° C. for 20 minutes. 23. Rinsing step Inner size of tank: 180 × 750 × 500 Processing conditions: The apparatus of (B) was operated, and processing was performed at room temperature for 5 minutes. No. The tanks 1, 3, 19, and 22 were larger tanks by the amount of the device (A).

Evaluation Maximum Current Density 12.0 A / dm ² Meshability of plating of through hole 90% or more σ 1.2 Gas pit defect rate 0%

[0090]

(1) According to the present invention, 0.03 to 0.05 mm
Thus, plating can be evenly performed on the inner surface of such a fine hole, and as a result, the failure rate of an IC laminated substrate or a printed wiring board can be significantly reduced. (2) According to the present invention, the limit value of the current density at which burns and burns at the time of plating start to be generated is greatly increased, so that the plating efficiency can be greatly improved. (3) The wrapping property (%) of the plating of the through-hole and the uniformity of the plating film indicated by σ were remarkably improved. (4) The gas pit defect rate (%) was significantly reduced. (5) It is extremely excellent in plating a printed wiring board for small holes with a high aspect ratio. (6) Products superior to conventional products can be obtained in a shorter time than before.

[Brief description of the drawings]

FIG. 1 is a plan view showing a specific example of an apparatus used in the present invention.

FIG. 2 is a front view of the apparatus of FIG.

FIG. 3 is a side view of the apparatus of FIG. 1;

FIG. 4 is a sectional view taken along line XX of FIG. 2;

FIG. 5 is a sectional view taken along line YY of FIG. 3;

FIG. 6 is an enlarged partial cross-sectional view showing one mode of fixing a vibrating blade to a vibrating rod.

FIG. 7 is a plan view showing an example of a lateral vibration stirring device.

FIG. 8 is a sectional view of FIG. 7;

FIG. 9 is a plan view showing another specific example of the device used in the present invention.

FIG. 10 is a front view of the device of FIG. 9;

FIG. 11 is a side view of the device of FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 treatment tank (pretreatment tank or plating tank) 2 swing frame 3 swing motor for swinging swing frame 4 vibration motor for vibration stirrer 5 cathode 6 anode 7 slide electrode holder 8 swing frame Cradle 9 Device cradle 10 Compressed air inlet for sending air to diffuser tube 11 Heater 12 Air diffuser tube 13 Cathode bar receiver 14 Oscillating frame vibration motor 16 Vibration bar 17 Vibrating blade 18 Vibrating blade fixing member 19 Vibration stress dispersion means 20 DESCRIPTION OF SYMBOLS 21 Upper support frame 22 Lower support frame 23 Fluoropolymer film 24 Screw 25 Vibration transmission frame 26 Balancer 27 Support rod with spring 28 Heater 29 Air compressor for aeration 30 Cathode booth bar receiver

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) C23C 18/16 C25D 21/10 301 B01F 11/00 C25D 7/00

Claims (6)

(57) [Claims] 1. A plating method for sequentially treating an object to be plated from a pretreatment step to a plating step, comprising: (A) a vibration generating means including a vibration motor, and a vibration bar which vibrates in a stirring tank in association with the vibration generation means. Vibrating blades fixed in multiple stages have an amplitude of 0.5 to 3.0 mm and a frequency of 200 to
Vibration stirring means for vibrating at 800 times / minute, an inverter for controlling the vibration motor to generate any vibration between 10 and 500 Hz, and a connection between the vibration generation means and the vibration stirring means (B) an aeration apparatus using a ceramic air diffuser having a pore diameter of 200 to 400 μm and a porosity of 30 to 40% as an aeration apparatus for a processing bath provided with a vibration stress dispersing means; ) A swinging device for giving a swinging width of 10 to 100 mm and a swinging speed of 10 to 30 times / min through an electrode bar on which the object to be plated is suspended. (D) The object to be plated is suspended. Via a descending electrode bar, using a vibration motor adjusted to 10 to 60 Hz by an inverter, an amplitude of 0.5 to 1.0 mm, and a frequency of 100 to 300 / Vibration apparatus for providing minute vibrations, at least a cleaning tank of the pretreatment process and the plating process for plating a continuous plating method characterized by activating the electroless plating bath and / or electrolytic plating bath. 2. The continuous plating method according to claim 1, wherein the object to be plated has small holes having a hole diameter of less than 0.1 mm. 3. The continuous plating method according to claim 2, wherein the object to be plated is a laminate having a plastic surface. 4. In the pretreatment step and the plating step, at least a cleaning tank, a washing tank, a catalyst tank, a washing tank, an electroless plating tank, a washing tank, an electrolytic plating tank and a tank comprising a washing tank are provided. 4. The method according to claim 1, wherein the object to be plated moves between the tanks at regular intervals.
The continuous plating method described. 5. The continuous plating method according to claim 1, wherein the number of Hz of the vibration motor of (D) is 50 to 65% with respect to the number of Hz of the vibration motor of (A). 6. The continuous plating method according to claim 1, wherein the vibrating blade in (A) is fixed by being sandwiched and fixed by a vibrating blade fixing member via a fluorine-based polymer film. .