JPH0577748B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to applying masking or the like to the surface of a synthetic resin substrate, a silicone or other ceramic substrate, or a semiconductive or insulative poorly conductive material such as a metal oxide. The present invention relates to a method of manufacturing various complex and fine metal deposition patterns by partially or selectively plating without any process, and particularly to a manufacturing method with improved manufacturing speed and efficiency.

An example of this type of plating method using electroplating is the selective electroplating method described in JP-A-55-148797. According to this publication, a cathode is provided in an electrolytic material, an anode is provided in the electrolytic material at a distance from the cathode, and an energy beam (laser) is used to heat the areas of the surface of the cathode that are to be selectively plated. Electromagnetic radiation (e.g., electromagnetic radiation such as Prior art has been disclosed that does the following. However, according to this prior art, to form a 10μ wide Ni line plating with a thickness of 0.2 to 0.4μ, the argon laser is focused into a beam with a diameter of 20μ and the intensity at the spot is 2×10 ⁵ . Between Ni evaporated cathode and anode as W/ ^cm2
When applying a DC plating potential of 1.5 V, the effective exposure time to the cathode must be 20 milliseconds, and the plating line traveling speed of the light source is 1 mm/sec (≒
60mm/min). And this means that in the above laser, the power intensity at the spot can be reduced to 4 by setting the beam spot diameter to less than half of the above value.
doubled and pulsed by mechanical chopping.
When plated under the same conditions as above while repeatedly irradiating 0.3 millisecond light pulses, the diameter was 6 μm thick.
As is clear from the fact that it takes 1 second to make a 30μ plating spot, it is far from being fast, but rather slow, and is suitable for various electronic devices such as ICs and LSIs that the above-mentioned prior art documents apply to. It could not be applied to printed circuit boards or the like except in special cases.

Furthermore, JP-A-55-148757 discloses a step of preparing a non-photosensitive plating bath, a step of bringing the object to be plated into contact with the plating bath, and a step of locally heating the contact surface to promote plating. applying an energy beam (electromagnetic radiation such as a laser) of sufficient intensity to the contact surface, the beam spot and the object to be plated so as to draw a predetermined plating pattern on the beam spot; A prior art technique has been disclosed in which selective plating (electroless or chemical plating that does not use electricity) is performed while relatively moving the material and the material. According to the plating method of the prior art, the plating speed for the plated object coated with Ni is converted using the conditions of the first prior art (plating thickness 0.2 to 0.4μ, plating width 10μ). Then, the plating speed is approximately 0.5 to 3.6 mm/sec (≒30 to 216 mm/
It is only to say that there are cases where the plating speed is twice as fast as that of the first prior art mentioned above, and it is difficult to apply it to the target integrated circuit etc. except in special cases. is considered to be inapplicable due to its slow speed.

In addition, since various electronic devices and substrates such as printed boards are usually insulators or semiconductors, the first and second methods described above involve selectively plating a predetermined pattern in the metal conductive surface area. What is described in the prior art documents cannot be applied to the substrate to be plated in the present invention without some kind of ingenuity. Unless the deposited film portion is preferably selectively removed, it is not possible to fabricate a device having a conductive pattern of metal or alloy on an insulating substrate.

The present invention has been proposed in view of these points, and an object of the present invention is to provide a selective plating method that enables high-speed plating and also allows plating of insulating substrates.

To achieve this objective, the selective plating method of the present invention involves applying an energy beam to a predetermined portion of an insulating substrate surface while a fluid containing a palladium compound is in contact with the surface of the insulating substrate. After depositing palladium on the irradiated area, the substrate is cleaned to remove the remaining fluid, and then
The method is characterized in that the surface of the substrate is brought into contact with a predetermined chemical plating solution, and metal is deposited by chemical plating using palladium deposited on the irradiated portion as a core.

The process of depositing palladium, which serves as a plating nucleus, on a predetermined pattern on the substrate surface is carried out at high speed, and in the subsequent process, conventional chemical plating can be applied to the entire deposited pattern. As a whole process, selective plating on predetermined portions of the substrate surface can be performed efficiently and at high speed.

In the present invention, when chemical plating is performed, palladium is used as a substance that serves as a precipitation nucleus of the plating metal. In addition to palladium, tin may also be used in combination, and compounds such as chlorides of these are used as contained in a liquid or paste-like fluid. Further, the substance used for the chemical plating is generally nickel, copper, gold, or the like. That is, the present invention performs chemical plating, but instead of using an energy beam in the metal deposition stage of chemical plating, it uses an energy beam in the pretreatment stage of chemical plating. By irradiating the precipitate, the formation of precipitate nuclei during chemical plating can be performed with high deposition efficiency and at high speed together with the formation of a predetermined pattern. Since it is sufficient to deposit metal, selective plating by chemical plating has come to be performed at high speed as a whole.

The details of the present invention will be explained below with reference to the embodiment shown in FIG. As shown in FIG. 1A, a substrate 3 to be selectively plated is set on an XY table 2 whose position is controlled by an NC device 1. Note that, as shown in FIG. 2A, for example, the substrate 3 is made by coating the surface of glass fiber 3A with epoxy resin 3B, and before setting it, it is washed with a neutral detergent and washed with water. It was washed thoroughly and then dried in an electric furnace or an open fire. At the same time, a palladium chloride solution 5 is sprayed onto the surface of the substrate 3 from a nozzle 4 at a rate of 50 ml/min, and at the same time, a laser device 6 including a modulator uses a convex lens 7 to spray a palladium chloride solution 5 with a diameter of 1 mm.
A laser beam of 1.5×10 ³ W/cm ² focused at 8
By irradiating the substrate 3 with , a line of precipitated palladium is drawn on the surface of the substrate 3 with a line width of 1 mm based on the numerical value generated by the NC device 1. Figure 2 B, C
By irradiating the laser beam 8 in the presence of the palladium chloride solution 5, a concave activation point (line) 3a is created on the surface of the substrate 3, and the palladium chloride solution 5 remaining at the activation point 3a is continuously laser·
It shows how precipitation nuclei 9 of palladium are formed by beam irradiation. Of course, these actions occur almost simultaneously within a very short time, and in some cases, the decomposition of palladium chloride in the solution 5 may precede the formation of the active sites 3a, and Even though the active point 3a is not a part that has obvious activity against the surrounding surface, since only the solution 5 in that part is heated by the laser beam, the energy of the laser beam is If is equal to or greater than a predetermined value, a palladium precipitation nucleus will be formed in that portion.

To explain activation by energy beams including laser beams, energy
When a beam is locally irradiated onto the surface of polymers such as synthetic resins, ceramics such as oxides, metals, etc., a temperature rise occurs in the irradiated area, or adsorbents on the surface (thin molecular layers of oxides, water, etc.) , dust, oil, etc.)
pops out, and an energetically or chemically clean surface appears. It can be said that the surface atoms of this cleaned outermost surface of a solid substance are in a state where the electronic structure is extremely unstable compared to the part covered with the adsorbate, so to speak. It forms a kind of excited state in which molecules and atoms are constantly trying to stick together in an attempt to resolve the state.
They are in a high energy state compared to atoms below the surface. Such a locally activated state is created at a desired location by irradiation with an energy beam.

The palladium chloride solution 5 used here had the following composition.

PdCl ₂ 0.25-12.5 g / 36% HCl 2.5-125 ml / C ₃ H ₈ O ₃ 0-200 ml / C ₂ H ₅ OH base Note that the above HCl is used to dissolve PdCl ₂ in ethanol (C ₂ H ₅ OH). In addition, glycerin (C ₃ H ₈ O ₃ ) was added to increase the viscosity of the solution and to make the solution 5 wet the substrate 3, and ethanol was used as the base. This is because this has the effect of etching the substrate 3 coated with the epoxy resin, and since the heat of evaporation is small, it also has the effect of reducing the laser power. In addition to this, acetone, water, etc. can be used as the base.

After forming the precipitation nuclei 9 as described above, a 10% hydrochloric acid aqueous solution is sprayed or injected from the nozzle 10 as shown in FIG. Wash off,
After washing away the hydrochloric acid solution with water, the substrate 3 is then immersed in a copper or nickel electroless plating solution 11 to perform electroless plating (chemical plating) as shown in FIG. 1C. In this electroless plating, as shown in FIG. 2D, copper or nickel 14 is deposited on the precipitation nuclei 9 made of palladium.

Here, the copper plating solution used for electroless plating in this example contains the following amount of substance in water.

Copper sulfate 7 g / Rothsiel's salt 20 g / Sodium carbonate 2 g / Sodium hydroxide 5 g / Formaldehyde 40% aqueous solution 25 ml / The Nickelmeck liquid had the following composition.

Nickel chloride 45g / Sodium hypophosphite 11g / Sodium citrate 100g / Ammonium chloride 50g / Then, as shown in Figure 1D, the substrate 3 is cleaned by flowing water through the nozzle 12 to increase the plating thickness. In such a case, as shown in FIG. 1E, the substrate 3 is immersed in an electroplating liquid 13 to perform electroplating. This electroplating may be carried out not only on the same metal but also on different metals such as silver, gold, etc.

When palladium is deposited using a laser beam as described above, the maximum speed is approximately 220 m/min (3.67 m/min).
It was possible to obtain a palladium deposition line speed for electroless plating of (m/sec). After drawing the palladium pattern on the substrate 3, it is plated by electroless plating, but this does not pose a problem in improving efficiency. This is because electroless plating proceeds at high speed using precipitation nuclei as a stop, and plating can proceed by immersing a large number of substrates 3 in a plating bath.

Here, instead of the above palladium chloride solution,
Almost the same results were obtained when a solution containing 0.04 M of Pd(NH ₃ ) ₂ (NO ₂ ) ₂ in ammonia water containing ammonium nitrate and sodium nitrite at pH 8.5 and 45° C. was used.

Further, as a fluid containing a palladium compound, a solution containing 0.1% palladium chloride and 0.3% hydrogen chloride in water is used, and as shown in FIG. is caused to flow down in a layered manner at a flow rate of 1 c.c./sec so that a liquid layer of 0.1 to 1 mm is formed on the surface of the substrate 3, the diameter of the output beam is 0.6 cm, the output is 10 W,
Using a CO ₂ laser with a wavelength of 10.6μ, it was possible to deposit palladium at a deposition line speed (scanning speed) of 44 cm/min. Therefore, 1
The area where palladium can be deposited per minute is 0.6×44=26.4cm ² /min. If the beam is shrunk to 0.06cm (0.6mm), it is possible to achieve a scanning speed of 26.4÷0.06=440cm/min. If we increase the laser power by 10 times, or 100W, with the same beam diameter, the scanning speed is proportional to the laser power, so
Scanning speed is also up to 10 times faster, i.e. 4400cm/min
(44m/min), which is approximately 0.7 when converted to speed per second.
m/sec. Note that the scanning speed is also proportional to the temperature and supply amount of the palladium chloride solution.

In the embodiment shown in FIG. 1, the palladium chloride solution is supplied by spraying onto the substrate, but the fluid containing the palladium compound may be in the form of a paste rather than a liquid.
In that case, as shown in FIG. 4, a coating mechanism may be employed in which a fluid 5 containing a paste-like palladium compound is coated onto the surface of the substrate 3 from a hopper 16 via a coating roller 17.

FIG. 5 shows another embodiment of the present invention. In this embodiment, the ultrasonic wave generator 18 is applied to the substrate 3 at a temperature of 10 to 50 km, for example, in order to promote the precipitation of palladium.
The laser beam 8 is irradiated while supplying the solution 5 to the substrate surface while applying Hz ultrasonic waves. According to this embodiment, the composition and supply of the solution 5 are the same as in the embodiment shown in FIG. Under conditions such as volume and laser beam intensity, it was possible to obtain about twice the deposition rate, and the scanning speed (deposition line path speed) for forming the pattern could be increased accordingly. Furthermore, by applying ultrasonic waves to the substrate 3, the same deposition rate could be obtained even if the laser beam output was reduced to 1/4.

FIG. 6 shows another embodiment of the present invention. In this embodiment, a band-shaped flexible synthetic resin material is used as the substrate 20, or by pasting the substrate on a band-shaped base material, a continuous This allows for processing. In FIG. 6, a substrate 20 that has been subjected to an appropriate cleaning process and is fed out from a supply reel 21 is immersed in a palladium compound solution 5 in an activation treatment tank 22, and a roller 23 provided in the treatment tank 22 is immersed in a palladium compound solution 5. A laser beam 8 focused by a convex lens 7 is irradiated from a laser device 6 to perform an activation process, that is, to deposit metal palladium along a predetermined image line, and then a guide roller outside the tank is guided. 24 and 25 with water jetted from the nozzle 26, and then the guide roller 2
7 and 28 and immersed in the electroless plating solution 11 of nickel or copper in the chemical plating bath 29 to perform electroless plating. In this case, the ion control tank 30
The plating solution 11 is circulated between the plating tank 29 and the chemical plating tank 29, and electrolysis is performed by connecting nickel or copper 31 to the anode so that the concentration of nickel or copper ions is constant. Next, guide rollers 32, 3 outside the tank
Washing with water jetted from the nozzle 26 for 3 minutes,
Next, the substrate 20 is guided by guide rollers 34 and 35 and immersed in an electroplating liquid 13 made of nickel, copper, gold and silver, etc. in an electroplating bath 36, and the chemically plated layer on the substrate 20 is connected to the cathode via a contact roller 37. and perform electroplating. Next, the portion pulled up via the guide roller 38 is dried by hot air etc. jetted from the nozzle 39 etc., and then collected by means such as winding up on a winding reel 40. The palladium compound solution 5 for activation treatment used in this example was obtained by dissolving 3.3 g of KCl, 2 g of PdCl ₂ and 25 ml of 36% HCl in 1 water. In addition to the palladium chloride solution, a tin chloride solution prepared by dissolving 25.2 g of SnCl ₂ .H ₂ O, 2.5 g of KCl, and 25 ml of 36% HCl in 1 part of water may be mixed and used in combination. Furthermore, in the case of activation treatment, when 1.5 g of AgNO ₃ was added as a sensitizer, the precipitation rate could be increased by about 20%.

In addition, the electroless plating solution containing nickel is a solution containing sodium citrate 0.2M boric acid 0.5M sodium subzincate 0.2M nickel sulfate 0.1M at pH 8 and 70℃, and containing copper. A solution containing 0.3M formaldehyde and 0.1M copper sulfate at pH 11 and 25°C was used.

If the above-mentioned continuous processing is performed, the work can be performed automatically and labor saving becomes easy.

When carrying out the present invention, the substrates 3 and 20 include ABS, polypropylene, epoxy, polyester, phenol, polyphenylene oxide,
Synthetic resins such as polyvinyl, urethane, acrylic, silicone, glass, porcelain such as alumina, etc. can be used. Further, as the energy beam, electromagnetic waves of 100 MHz or more can be used.

As described above, according to the present invention, an energy beam is not used in the metal deposition stage of chemical plating, but in the pretreatment stage of chemical plating.
By irradiating a predetermined portion of the substrate surface with an energy beam while a fluid containing a palladium compound is in contact with the surface of the insulating substrate, palladium is deposited on the irradiated portion,
When chemical plating is performed, the substance (palladium) that becomes the precipitation nucleus of the plating metal is deposited in a predetermined pattern shape at an extremely high speed, so it is possible to perform selective plating in a predetermined pattern on an insulating plate at high speed. can. Further, according to the present invention, the amount of wear and tear of the nuclear precipitation solution for chemical plating and the electroless plating solution corresponds to the amount of selective plating of a predetermined pattern, etc., so there is no waste and it is extremely economical. It is.

[Brief explanation of the drawing]

Figure 1 is a process diagram showing one embodiment of the present invention, Figure 2 is a process diagram showing an embodiment of the present invention.
The figure is a diagram of the principle when implementing the method of the present invention.
5 through 5 are diagrams showing another example of the activation process of the present invention, and FIG. 6 is a process chart showing another embodiment of the present invention. 1...NC device, 2...XY table, 3,2
0... Substrate, 4... Nozzle, 5... Palladium chloride solution, 6... Laser device, 7... Convex lens, 8
...Laser beam, 9...Precipitation nucleus, 10,12
... Nozzle, 11 ... Chemical plating liquid, 13 ... Electroplating liquid, 14 ... Nickel or copper, 18 ...
...Ultrasonic generator.

Claims (1)

[Claims] 1. With a fluid containing a palladium compound in contact with the surface of an insulating substrate, a predetermined portion of the substrate surface is irradiated with an energy beam to deposit palladium on the irradiated portion. After that, the substrate is cleaned to remove the remaining fluid, and then the surface of the substrate is brought into contact with a predetermined chemical plating solution to deposit metal by chemical plating using the palladium deposited on the irradiated portion as a nucleus. A selective plating method characterized by: 2. The selective plating method according to claim 1, wherein the energy beam is a laser beam. 3. The selective plating method according to claim 1, wherein the palladium compound is palladium chloride. 4. The selective plating method according to claim 1, wherein the fluid containing the palladium compound is an aqueous solution of the palladium compound. 5. The selective plating method according to claim 1, wherein the fluid is a paste-like material. 6. The selective plating method according to claim 1, wherein the fluid contacts the substrate surface by flowing the fluid in a layered manner along the substrate surface. 7. The selective plating method according to claim 1, wherein the contact of the fluid to the substrate surface is performed by applying the fluid to the substrate surface in a layered manner. 8. The selective plating method according to claim 1, wherein the fluid contacts the substrate surface by spraying the fluid onto the substrate surface. 9. The selective plating method according to claim 1, wherein the substrate is vibrated by ultrasonic waves when the substrate surface is irradiated with the energy beam. 10. The selective plating method according to claim 1, wherein the insulating substrate is made of a long strip plate, and the chemical plating is performed sequentially in the length direction. 11. The selective plating method according to claim 1, wherein the insulating substrate is made of synthetic resin. 12. The selective plating method according to claim 1, wherein the insulating substrate is made of porcelain. 13. The selective plating method according to claim 1, wherein the chemical plating is nickel plating. 14. The selective plating method according to claim 1, wherein the chemical plating is copper plating. 15. The selective plating method according to claim 1, wherein the irradiation of the energy beam onto a predetermined portion of the substrate surface is performed by relative numerically controlled movement of the beam and the substrate. 16. The selective plating method according to claim 1, wherein electroplating is further performed on the substrate on which metal has been deposited by the chemical plating.