JPH07245467A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To accurately form an initiator pattern uniform in concentration by a method wherein the initiator pattern is composed of collective dots of aqueous ink discharged out from an ink jet printer, and then solvent is removed. CONSTITUTION:A collective body 4 of dots 2 of aqueous ink is printed on the surface of an insulating board 10 by an ink jet printer for the formation of an initiator pattern. At this point, the dot 2 is about 25 to 200mum in diameter, and the dots 2 are separated from each other by a distance equal to 1/2 to 1/1 of its diameter. Then, the insulating board 10 is dried out, solvent 3 contained in an ink drop 4 is completely evaporated, and thus the initiator pattern formed of bivalent palladium ions 2 set in array is obtained. Thereafter, the insulating board 10 is cleaned with ion exchange water, and palladium ion 2 serving as catalyst is activated by treatment into activated palladium catalyst 5. Then, the board 10 is dipped into an electroless copper plating solution to form a conductor pattern 6 on the activated palladium catalyst 5. By this setup, a conductor pattern with a high accuracy of line width and adhesive strength to an insulating board can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a printed wiring board, and more particularly to a method for forming an initiator pattern for electroless copper plating in the additive method.

[0002]

2. Description of the Related Art A conventional method for manufacturing a printed wiring board is disclosed in, for example, Japanese Patent Application Laid-Open Nos.
As disclosed in Japanese Patent No. 81490, a method of manufacturing an inexpensive printed wiring board by forming an initiator pattern on an insulating substrate by an inkjet printing method and then forming a conductor pattern by electroless copper plating is devised. Has been done.

[0003]

However, in the method of manufacturing a printed wiring board for forming an initiator pattern by the conventional ink jet printing method, the ink used in the ink jet printing method is a water-insoluble material such as toluene or xylene. Viscosity adjusting agent, surface tension adjusting agent, dispersion stabilizer, and additives for fixing the ink on the insulating substrate after printing, for example, epoxy resin and phenol resin, are added to the organic solvent having a non-electrolytic property, such as palladium chloride. It was a dispersion of fine particles of a catalyst necessary for fixing copper plating.

Therefore, when the ink is used in the ink jet printing machine to form the initiator pattern on the insulating substrate, the tip of the ink ejection nozzle of the ink jet printing machine is affected by the additive in the ink. In addition, the catalyst fine particles are likely to be attached to cause clogging, and even if the ink is ejected onto the insulating substrate, aggregation is likely to occur due to the additive added to the ink and remains as a viscous material or solid. There is a problem with stable drawing. That is, since the viscous material or solid that is not chemically bonded to the insulating substrate remains on the insulating substrate, it becomes difficult to form an initiator pattern having a uniform concentration.

As a result, the conductor pattern formed by the electroless copper plating process on the initiator pattern formed in a non-uniform concentration has a low adhesion strength with the insulating substrate and has a line of the conductor pattern. The width easily varies, which is a serious obstacle to the reliability of the printed wiring board and the miniaturization of the conductor pattern.

Therefore, the present invention has been made in order to solve the above problems, and an object thereof is to form an initiator pattern for electroless copper plating with a uniform concentration with high accuracy, thereby making the conductor pattern reliable. It is to provide a method for manufacturing a printed wiring board that enables the miniaturization and miniaturization.

[0007]

In order to achieve the above object, the present invention provides a method for producing a printed wiring board by electroless copper plating on an initiator pattern formed on an insulating substrate, wherein the initiator pattern is It is formed by forming an aggregate of dots of a water-based ink ejected by an inkjet printing machine and then removing the solvent. The dot diameter of the water-based ink forming the initiator pattern is 25 μm to 200 μm, and the distance between the adjacent dot centers is ½ of the dot diameter.
~ Be in 1/1. The aqueous ink is composed of a soluble palladium salt, a water-soluble organic solvent, and water, and the concentration of divalent palladium ions in the aqueous ink is 0.1.
g / l to 3.0 g / l, and the water-soluble organic solvent does not remain as a viscous material or solid after drying.
Is characterized by.

[0008]

In the present invention configured as described above, the use of the water-based ink in the formation of the initiator pattern by the inkjet printing method causes clogging at the tip of the nozzle for ejecting the water-based ink. Therefore, the aggregate of dots can be stably formed on the insulating substrate. Further, the initiator pattern drawn by the water-based ink does not have the viscous material or solid that hinders the aggregation of the water-based ink or the fixing of electroless plating, and further the palladium ion in the water-based ink Since it is chemically fixed on the insulating substrate, it is possible to form an initiator pattern having strong adhesion.

Further, by appropriately controlling the divalent palladium ions in the water-based ink, the dot diameter of the water-based ink, and the distance between the dot centers, the initiator pattern having a uniform density can be isolated. It can be formed on a substrate.

The divalent palladium ion concentration in the aqueous ink is 0.1 g / l to 3.0 g / l, and more preferably 0.4 g / l to 1.0 g / l. The reason for this is that when the divalent palladium ion concentration is 0.1 g / l or less, the electroless plating is apt to become unfixed, and 3.0
This is because the adhesion strength of the electroless copper plating cannot be obtained when it is at least g / l.

Further, the dot diameter is 25 μm to 200 μm.
And the distance between the dot centers is 1/2 to 1 of the dot diameter.
A value of / 1 is appropriate. The reason for this is that if the dot diameter is 25 μm or less, electrical characteristics such as insulation properties required for a printed wiring board cannot be satisfied. 200
This is because the ink amount of the ejected dots is not stable when the thickness is μm or more. Furthermore, the distance between the dot centers is 1 /
When it is 2 or less, the uniformity of the initiator pattern is hindered, and when it is 1/1 or more, a gap occurs between the dots and the conductor pattern cannot be formed, and the function as the printed wiring board is obtained. Can't get

Therefore, the conductor pattern formed by the electroless copper plating process on the initiator pattern has a high adhesion strength with the insulating substrate and a high line width accuracy.

[0013]

Embodiments of the present invention will be described below with reference to FIGS. (Embodiment 1) FIG. 1 schematically shows a cross section of a conductor pattern of a printed wiring board according to the present invention. An insulating substrate 10 made of a glass epoxy resin having a concavo-convex pattern formed by matting the surface is dipped in a sodium hydroxide solution,
Then, by dipping in a sulfuric acid solution, oil and fat components or adhered foreign substances that hinder the fixability of the conductor pattern 11 by electroless copper plating on the substrate 10 were washed and removed.

Next, the solvent remaining on the surface of the insulating substrate 10 in the washing step is washed in a washing tank made of ion-exchanged water, and then dried at a temperature of 80 ° C. for 15 minutes to print the initiator pattern 13. The insulating substrate 10 is used for the above.

An initiator pattern 1 serving as a core for forming the conductor pattern 11 on the insulating substrate 10 is formed.
In order to draw the image No. 3, a fixed nozzle of a dot-on-demand type inkjet printer that ejects a water-based ink and a table that is relatively movable in the X-axis direction and the Y-axis direction that are orthogonal to each other are used. A group of dots having a dot diameter of 100 μm and a dot interval of 70 μm was printed using the aqueous ink having the composition shown in (1) to draw an initiator pattern 13 having a desired line width. At this time, a set of dots on which the pattern is drawn has a regular array such as a grid pattern shown in FIG. 2 or a zigzag pattern shown in FIG.
Further, the dot diameter and the dot interval were changed according to the line width to correspond to the formation of the fine structure of the pattern.

Then, the insulating substrate 10 having the initiator pattern 13 printed thereon is dried at 80 ° C. for 10 minutes,
As shown in FIG. 4 (a), an ink droplet 4 having a dot diameter of 100 μm ejected from an inkjet printer in which divalent palladium ions 2 are in a completely dissolved state, the solvent 3 in the ink droplet 4 is dried by drying in this step. Completely distracted, Figure 4
As shown in (b), an initiator pattern formed by arranging divalent palladium ions 2 on the insulating substrate 10 was formed.

Then, the insulating substrate 10 having the dried initiator pattern was washed with ion-exchanged water, and the catalyst was activated according to a conventional method. Next, the insulating substrate is electroless copper-plated bath (Shipley Co., Ltd .: Cuposit)
20 μm on the initiator pattern for 10 hours.
Copper plating of m thickness is deposited to form a conductor pattern (Fig. 4).
(C)) was done.

[0018]

[Table 1]

The adhesion strength between the insulating substrate of the printed wiring board thus manufactured and the electroless copper-plated film is measured according to JIS-
It was measured by the method of C-6481. As a result, the peel strength of the electroless copper plating film formed on the initiator pattern by the conventional oil-based ink is 1.0 kg / cm, whereas the peel strength of the printed wiring board of this embodiment is 1.8 kg / cm. Met.

(Embodiment 2) The insulating substrate obtained by etching away the fine polyamide particles on the surface of the polymer alloy substrate made of polycarbonate-polyamide with a solvent (for example, 10 wt% hydrochloric acid) is made of the glass epoxy resin in the first embodiment. The same effect was able to be obtained by using it instead of an insulating substrate and manufacturing in the same process as Example 1.

As the insulating substrate used in the printed wiring board of the present invention, glass epoxy, glass triazine, glass polyimide, polyethylene terephthalate,
It is preferable to use any one selected from polymer alloys such as polycarbonate ABS, polycarbonate polyamide, polyphenylene ether ABS, and polyphenylene ether polyamide. Further, the catalyst constituting the aqueous ink of the above (1) is a palladium hydroxide solution or a palladium chloride aqueous solution, and the solvent of the ink is liquid and water-soluble methanol, ethanol, isopropyl alcohol, n. −
Butanol, 1,3-butanediol, 2-methyl-
Either 2,4-pentadiol or diethylene glycol, or glycerin can be used.

[Brief description of drawings]

FIG. 1 is a schematic view for explaining a cross section of a conductor pattern formed on a printed wiring board according to the present invention.

FIG. 2 is a diagram for explaining a dot formation state of a water-based ink forming an initiator pattern according to the present invention.

FIG. 3 is a diagram for explaining a dot formation state of a water-based ink, similar to FIG.

FIG. 4A is a cross-sectional view of a dot of water-based ink formed on an insulating substrate, and FIG. 4B is a cross-sectional view of the dot of water-based ink formed on an insulating substrate. FIG. 4C is a cross-sectional view showing a state, and FIG. 4C is a cross-sectional view showing a state in which electroless copper plating is formed on the activated palladium catalyst formed by drying the aqueous ink on the insulating substrate.

[Explanation of sign]

 10 Insulating Substrate 11 Conductor Pattern 13 Initiator Pattern 2 Divalent Palladium Ion 3 Aqueous Ink Solvent 4 Aqueous Ink Drop 5 Active Palladium Catalyst 6 Electroless Copper Plating Film

Claims (3)

[Claims] 1. A method for producing a printed wiring board by performing electroless copper plating on an initiator pattern formed on an insulating substrate, wherein the initiator pattern is an aggregate of dots of an aqueous ink ejected by an inkjet printer. A method of manufacturing a printed wiring board, which comprises forming and then removing a solvent. 2. The aqueous ink comprises a soluble palladium salt, a water-soluble organic solvent and water, and the concentration of divalent palladium ions in the aqueous ink is 0.1 g / l to 3.
The method for producing a printed wiring board according to claim 1 or 2, wherein the water-soluble organic solvent does not remain as a viscous material or a solid after being dried at 0 g / l. 3. The dot diameter of the water-based ink forming the initiator pattern is 25 μm to 200 μm, and the distance between the adjacent dot centers is 1 of the dot diameter.
It exists in / 2-1 / 1, The manufacturing method of the printed wiring board of Claim 1 characterized by the above-mentioned.