JPH05327190A - Method for printing printed circuit board - Google Patents

Abstract

PURPOSE:To print a printed circuit board by an ink jet printer without fear of impairing the electric characteristics of the board. CONSTITUTION:A circuit protective film 2 in which inorganic ion exchange is mixed is provided on a surface of a printed circuit board 1. The surface of the film 2 is printed by an ink jet printer. Ions such as charge agent in ink of the printer are collected by the exchange mixed in the film 2 to prevent the ions in the ink from acting on a circuit 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method for marking and printing a product number or the like on the surface of a printed wiring board.

[0002]

2. Description of the Related Art Generally, a product number, a lot number, a company symbol mark, a care mark or the like is printed on the surface of a printed wiring board by screen printing. However, in the case of screen printing, it is necessary to make a screen plate, and even in the case of producing a large amount of a small amount of products, there is a problem that the work efficiency becomes poor and the cost becomes high if such a plate is made.

Therefore, the applicant of the present invention has proposed to perform printing by printing on the surface of a printed wiring board using an ink jet printer. According to the inkjet printer, it is possible to print with arbitrary characters etc. according to the input data to the computer without using a plate. Moreover, the inkjet printer can print on the surface of the printed material like the wire dot printer. Since it can be printed without any impact and even if there is some unevenness on the surface, it is most suitable as a device for printing on a printed wiring board having a circuit formed on the surface.

As the ink jet printer, a well-known one which has been conventionally used is used.
FIG. 4 shows the principle of the charge deflection type inkjet printer. In FIG. 4, 11 is a nozzle provided with a piezo element 12, 13 is a charging electrode, 14 is a deflection electrode, 15 is a gutter,
Reference numeral 16 is a sensor, from the ink reservoir 17 to the nozzle 11
The ink 18 supplied to the nozzles 12 is ejected from the nozzles 12 as ink particles 10 by the action of the piezo element 12. Characters to be printed are divided into dots in a matrix, and each ink particle 10 is charged by a charging electrode 13 with a voltage proportional to the position information of each pixel. When passing through the space, it is deflected according to the amount of charge, reaches the surface of the printed wiring board 1, and printing can be performed with predetermined characters and the like. The ink particles 10 that are not used for printing are not charged by the charging electrode 13, go straight, are caught by the gutter 15, and are collected in the ink reservoir 17.

As described above, in a general charge-deflection type ink jet printer, since printing is performed by charging and deflecting ink particles, lithium ink, cyanate or the like is added to the ink as a charging agent. Ink specific resistance value is 800 Ωcm to 20
It is about 00 Ωcm. The charging agent is 0.1
About 5% by weight is blended.

[0006]

However, as described above, in the charge-deflection type ink jet printer, since the ink contains a charging agent such as lithium nitrate or cyanate, the ink contains ions, and therefore the ink jet printer has a problem. When printing is performed on the surface of the printed wiring board, the ions may act on the circuit of the printed wiring board to cause dielectric breakdown under high temperature and high humidity conditions. Also, FIG.
As described above, a comb-shaped pattern 20 having a pattern width of 1 mm and a pattern interval d = 1.5 mm is formed on the surface of the printed wiring board, and a solder resist is applied on the comb-shaped pattern 20 to form a thickness of 10
A circuit protection film of μ is provided, the entire surface is printed on the circuit protection film by an ink jet printer, and a test is performed by continuously applying a voltage of DC100V for 500 hours under the conditions of 60 ° C. and 95% RH. 20
In some cases, migration occurs between the electrodes and the insulation between the electrodes of the comb pattern 20 cannot be ensured. Even if migration does not occur, the insulation resistance value between the comb patterns 20 is about 10 ¹³ to 10 ^{14 and} 10 ⁷ to 1
0 decreases to about ⁸ was achieved, there is a problem in securing the insulation. In addition, even in a place where ink does not adhere, the ink may scatter after adhering to the surface of the printed wiring board and adhere to the surroundings, or particles of a prescribed size (about 60 to 100 μ) may scatter from the nozzle. Then, the same problem occurs.

It is not necessary to use an ink containing a charging agent in an ink jet printer of a bubble jet type, a static control type, or a drop-on-mind type, which is not a charge-deflection type. Pigments and other additives include ionic ones, and as long as they are used in printed wiring boards, they cause more or less problems in terms of insulation.

The present invention has been made in view of the above points, and provides a printing method for a printed wiring board that can be printed by an ink jet printer without having a bad influence on the electrical characteristics of the printed wiring board. The purpose is that.

[0009]

A method for printing on a printed wiring board according to the present invention is such that a circuit protective film containing an inorganic ion exchanger is provided on the surface of the printed wiring board and an ink jet printer is used on the surface of the circuit protective film. It is characterized by printing.

[0010]

[Function] Ions in the ink of the ink jet printer printed on the surface of the circuit protection film are captured by the inorganic ion exchanger compounded in the circuit protection film, and the ions in the ink act on the circuit of the printed wiring board. Can be prevented.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples. The printed wiring board 1 is created by providing a circuit 5 on the surface of an insulating substrate 4 with a copper foil pattern or the like. As the insulating substrate 4, glass cloth, glass non-woven fabric, paper, or a combination thereof is used as a base material. Formed with thermosetting resin-based or thermoplastic resin-based organic substrates such as epoxy resin substrates, phenol resin substrates, polyester resin substrates, and Teflon resin substrates used, inorganic substrates such as ceramic substrates, and other organic / inorganic mixed materials Any of the above can be used. The surface of the printed wiring board 1 is covered with a circuit protective film 2 so as to cover the circuit 5.

The circuit protection film 2 can be formed of, for example, a solder resist. A liquid solder resist is preferably used as the solder resist. As the liquid solder resist, a one-liquid thermosetting solder resist (such as "S-40" manufactured by Taiyo Ink Mfg. Co., Ltd.),
Two-component thermosetting solder resist (such as "S-100W" manufactured by Taiyo Ink Manufacturing Co., Ltd.), liquid photo solder resist ("PSR-4000" manufactured by Taiyo Ink Manufacturing Co., Ltd.)
Etc.), UV curable solder resist (“USR-2G” manufactured by Tamura Seisakusho etc.) and the like can be used. This solder resist may be blended with a white pigment, a dye such as yellow or green, or a pigment.

In the present invention, the inorganic ion exchanger is contained by blending the powder of the inorganic ion exchanger with the liquid solder resist, applying the liquid solder resist on the surface of the printed wiring board 1 and curing it. The circuit protection film 2 is created. The inorganic ion exchanger is a substance capable of ion-exchanged with the inorganic ion exchanger and trapped, and known ones disclosed in JP-A-59-170173 and the like can be used. Specifically, those provided as "IXE" series by Toagosei Kagaku Kogyo Co., Ltd. can be used. Among the "IXE" series, "IXE-10
0 "(zirconium-based cation exchange type)," IXE
-150 "(zirconium cation exchange type),
"IXE-200" (tin-based cation exchange type),
Grades such as "IXE-300" (antimony cation exchange type), "IXE-400" (titanium cation exchange type), "IXE-600" (antimony and bismuth ion exchange type) are preferred. These inorganic ion exchangers are powders of extremely small particles having a specific gravity of about 5.5 and an average particle size of about 1 to 2 μ. To be mixed with a liquid solder resist, it should be sufficiently mixed with a three-roll or a stirrer. Must be dispersed evenly. The compounding amount of the inorganic ion exchanger can be arbitrarily set as required.

On the other hand, inks used in ink jet printers include UV curable inks, thermosetting inks,
Any water-based ink, water-based thermosetting ink, solvent-based ink, or the like can be used. When the circuit protection film is formed by a solder resist, since the solder resist is generally a thermosetting type or a UV curing type, the ink is also of the same type as the U type.
V-curable ink and thermosetting ink are preferred. An example of the composition of each of the UV curable ink and the thermosetting ink is shown. (UV curable ink) -Charging agent (salts) 2 parts by weight-Dye, pigment (titanium oxide etc.) 10 parts by weight-Acrylate oligomer 35 parts by weight-Acrylate oligomer 15 parts by weight Photoinitiator 5 parts by weight Parts: MEK: 30 parts by weight Methyl alcohol: 20 parts by weight Others (Small amounts of surfactants, glycols, stabilizers, antioxidants, anti-corrosion agents, etc.) (thermosetting ink) -Charging agents (salts) … 0.2 parts by weight ・ Dye, pigment (titanium oxide etc.)… 10 parts by weight ・ Acrylic monomer… 35 parts by weight ・ Melamine resin… 15 parts by weight ・ Epoxy resin… 5 parts by weight ・ MEK… 30 parts by weight ・ Methyl alcohol 20 parts by weight ・ Others (a small amount of surfactants, glycols, stabilizers, antioxidants, anti-corrosion agents, etc.) These are diluted solvents (85 parts by weight of MEK and methyl). By dilution with alcohol 15 parts by weight mixed solvent of), specific resistance 1000 .OMEGA.cm, viscosity 4 cps (25 ° C.), are those that can be used to prepare the surface tension 30 dyn / cm. Of course, the ink is not limited to the above-exemplified inks, and the charging agent (salt) 0.0
01 to 10% by weight, dye or pigment 5 to 35% by weight, resin component (vinyl acetate, epoxy, acryl, phenol, melamine, etc.) 5 to 60% by weight, solvent 10 to 90% by weight, specific resistance 500. ~ 2500 Ωcm, viscosity 2-2
It is possible to use those generally prepared to 0 cps and a surface tension of 10 to 600 dyn / cm.

As the charging agent to be added to the ink,
It is preferable to use lithium nitrate (LiNO ₃ ). K
It is also possible to use a Na-based salt or the like. However, since a large amount of these may lead to deterioration of the original characteristics and performance of the ink, a cyanate may be used. Acid salts lack stability. For this,
Although not particularly limited, LiNO is used as the charging agent.
_It is preferable to use ₃ . When LiNO ₃ is used as the charging agent as described above, a zirconium-based inorganic ion exchanger having a high Li ion ion-exchange capacity is used as the inorganic ion exchanger (for example, “IXE-100” manufactured by Toagosei Kagaku Kogyo Co., Ltd., supra). , "IXE-150") is preferably used.

As an ink jet printer,
The charge deflection type inkjet printer shown in FIG. 4 can be used. A specific example of conditions for printing on the surface of the printed wiring board 1 using this inkjet printer will be described. First, the piezo element 12 is vibrated at a frequency of 20 kHz, and the ink pressure is 3 Bar and the nozzle diameter is 6
The ink 18 is ejected in a granular form from the 0 μ nozzle 11, and the ink particles 10 are charged by the charging electrode 13. Deflection electrode 1
4 are arranged at intervals of 8 mm, and DC500V to 10
The voltage is applied to 00V, and the ink particles 10 are deflected and swung by the deflection electrode 14 in a width of 0 to 10 mm while flying for about 8 cm, and the ink particles 10 are applied to the surface of the printed wiring board 1 as shown in FIG. Printing can be performed by reaching it. The non-charged ink particles 10 travel straight and are received by the gutter 15 and do not adhere to the printed wiring board 1. The ink particles 10 received by the gutter 15 are collected in the ink reservoir 17 and reused after being regenerated by stirring or adjusting the viscosity. Printing can be performed by fixing the nozzle 11 of the inkjet printer and moving the printed wiring board, but a method of moving the nozzle 11 may be used. Further, when high-speed printing (printing) is required, a multi-nozzle system in which a plurality of nozzles 11 are provided in parallel can be adopted. It is preferable to cover the area from the nozzle 11 to the surface of the printed wiring board 1 to be printed so that the flight of the ink particles 10 is not affected by the flow of air, but the ink attached to the printed wiring board 1 is dried. 5 to 1000 cm / sec of air rectification to accelerate bleeding and prevent repelling
Sending at moderate wind speed is effective. In the present invention, the ink jet printer is not limited to the above-described charge deflection type ink jet printer, but may be a bubble jet type, a static control type, a drop-on-mind type ink jet printer, or the like. ..

As shown in FIG. 1, when the printed wiring board 1 is printed with an ink jet printer and the ink particles 10 adhere to the circuit protection film 2 provided on the surface of the printed wiring board 1, the ink particles 10 are contained in the ink. Ions such as a charging agent that migrate inside the circuit protection film 2 act on the circuit 5. However, since the circuit protection film 2 contains an inorganic ion exchanger, this ion is an inorganic ion exchange material. The ions in the ink are captured by being exchanged with the body, and it is possible to prevent the ions in the ink from reaching the circuit 5 and acting, and the insulating property is lowered by the action of the ions contained in the ink of the inkjet printer. It is something that you will never do. As a result, even if the migration test of FIG. 5 is performed, the migration does not occur. The ion removal rate by the inorganic ion exchanger reaches 60 to 98%, and the ion exchange capacity of the inorganic ion exchanger is increased by heating. Therefore, the printed wiring board is heated to about 100 to 160 ° C after printing. It is effective to heat for about 30 minutes to enhance the ion trapping effect. Therefore, even when using a solvent type ink that does not originally require heat curing,
It is preferable to perform heating in order to increase the ion capturing efficiency. However, it should be noted that heating or exceeding the glass transition temperature of the substrate material in the manufacturing process of the printed wiring board 1 may cause deformation or dimensional shrinkage. In the case of the printed wiring board 1 made of phenol resin, epoxy resin, polyester resin, etc.,
It is preferable to stop the treatment at 160 ° C. or lower within 10 to 30 minutes. Therefore, when a thermosetting ink is used as the ink, it is necessary to use one that cures under this heating condition. Further, when the UV curable ink is used, the substrate of the printed wiring board 1 may be discolored or deteriorated depending on the total UV irradiation amount in each step such as the solder resist step.
It is preferable to use a material that cures at a V irradiation amount of 4000 mj or less.

FIG. 2 shows another embodiment of the present invention, in which the circuit protection film 2 is formed of two layers of a lower film layer 2a and an upper film layer 2b, for example, a liquid solder resist is used. The circuit protection film 2 is formed by applying the coating layer twice. One of the two layers, the lower film layer 2a and the upper film layer 2b, for example, the lower film layer 2a contains an inorganic ion exchanger, and the ink is printed and attached to the surface of the circuit protection film 2 by an inkjet printer. Of the ions in the particles 10, the ions that have passed through the upper membrane layer 2b and reached the lower membrane layer 2a are ion-exchanged and captured by the inorganic ion exchanger in the lower membrane layer 2a, and the ions act on the circuit 5. Can be prevented. Since only the ions that pass through the upper membrane layer 2b need to be captured in this case, the amount of expensive inorganic ions used can be reduced. Of course, the lower layer film 2a and the upper layer film 2
The upper layer membrane 2b of b may contain an inorganic ion exchanger.

When an inorganic ion exchanger is blended in the upper film layer 2b when the circuit protective film 2 is formed of two layers of the lower film layer 2a and the upper film layer 2b, it is printed by an ink jet printer as shown in FIG. Part only, ink particles 1
The upper membrane layer 2b containing the inorganic ion exchanger may be provided only in the portion where 0 is attached. Therefore, also in this case, the amount of expensive inorganic ions used can be small.

Further, a circuit protective film 2 containing an inorganic ion exchanger is formed by blending a fine powder of an inorganic ion exchanger with a liquid protective film agent such as a liquid solder resist and applying it to the surface of the printed wiring board 1. At this time, the liquid protective film agent is prepared to have a low viscosity, and the liquid protective film agent is applied to the surface of the printed wiring board 1 and then the liquid protective film agent is prepared so as to have sufficient time for curing, whereby a finely powdered inorganic ion exchanger is prepared. It can be made to settle and unevenly distributed under the circuit protection film 2. When the inorganic ion exchanger is unevenly distributed so that the density is high, the capture rate of the inorganic ion exchanger when the ions pass through this portion is increased, and the amount of expensive inorganic ion used is small. It's done.

In each of the above embodiments, the liquid solder resist containing the inorganic ion exchanger is applied to the surface of the printed wiring board 1 to form the circuit protective film 2 containing the inorganic ion exchanger. A dry film photoresist prepared by adding an inorganic ion exchanger is laminated on the surface of the printed wiring board 1 to form the circuit protective film 2 containing the inorganic ion exchanger. Good.

[0022]

As described above, according to the present invention, the circuit protection film containing the inorganic ion exchanger is provided on the surface of the printed wiring board, and the surface of the circuit protection film is printed by the ink jet printer. Ions such as charging agents in the ink of the ink jet printer printed on the surface of the film are captured by the inorganic ion exchanger compounded in the circuit protection film, preventing the ions in the ink from acting on the circuit of the printed wiring board. In addition, it is possible to perform printing with an ink jet printer without fear of adversely affecting the electrical characteristics of the printed wiring board.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view showing an embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view showing another embodiment of the present invention.

FIG. 3 is a partially enlarged cross-sectional view showing still another embodiment of the present invention.

FIG. 4 is a schematic diagram showing the principle of an inkjet printer.

FIG. 5 is a schematic view showing a comb-shaped pattern used for an electromigration test.

[Explanation of symbols]

 1 printed wiring board 2 circuit protection film 2a lower film layer 2b upper film layer 5 circuit 10 ink particles

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] March 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

On the other hand, inks used in ink jet printers include UV curable inks, thermosetting inks,
Any water-based ink, water-based thermosetting ink, solvent-based ink, or the like can be used. When the circuit protection film is formed by a solder resist, since the solder resist is generally a thermosetting type or a UV curing type, the ink is also of the same type as the U type.
V-curable ink and thermosetting ink are preferred. An example of the composition of each of the UV curable ink and the thermosetting ink is shown. (UV curable ink) -Charging agent (salts) 2 parts by weight-Dye, pigment (titanium oxide etc.) 10 parts by weight-Acrylate oligomer 35 parts by weight-Acrylate oligomer 15 parts by weight Photoinitiator 5 parts by weight Parts: MEK: 30 parts by weight Methyl alcohol: 20 parts by weight Others (Small amounts of surfactants, glycols, stabilizers, antioxidants, anti-corrosion agents, etc.) (thermosetting ink) -Charging agents (salts) … 0.2 parts by weight ・ Dye, pigment (titanium oxide etc.)… 10 parts by weight ・ Acrylic monomer… 35 parts by weight ・ Melamine resin… 15 parts by weight ・ Epoxy resin… 5 parts by weight ・ MEK… 30 parts by weight ・ Methyl alcohol 20 parts by weight ・ Others (a small amount of surfactants, glycols, stabilizers, antioxidants, anti-corrosion agents, etc.) These are diluted solvents (85 parts by weight of MEK and methyl). By dilution with alcohol 15 parts by weight mixed solvent of), specific resistance 1000 .OMEGA.cm, viscosity 4 cps (25 ° C.), are those that can be used to prepare the surface tension 30 dyn / cm. Of course, the ink is not limited to the above-exemplified inks, and the charging agent (salt) 0.0
01 to 10% by weight, dye or pigment 5 to 35% by weight, resin component (vinyl acetate, epoxy, acryl, phenol, melamine, etc.) 5 to 60% by weight, solvent 10 to 90% by weight, specific resistance 500. ~ 2500 Ωcm, viscosity 2-2
It is possible to use those generally prepared to 0 cps and a surface tension of 15 to 50 dyn / cm.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

As an ink jet printer,
The charge deflection type inkjet printer shown in FIG. 4 can be used. A specific example of conditions for printing on the surface of the printed wiring board 1 using this inkjet printer will be described. First, the piezo element 12 is vibrated at a frequency of 20 kHz, and the ink pressure is 3 Bar and the nozzle diameter is 6
The ink 18 is ejected in a granular form from the 0 μ nozzle 11, and the ink particles 10 are charged by the charging electrode 13. Deflection electrode 1
4 are arranged at intervals of 8 mm, and DC500V to 8k
The ink particles 10 are applied to V and are deflected and deflected by the deflection electrode 14 in a width of 0 to 10 mm while flying for about 8 cm, and the ink particles 10 are applied to the surface of the printed wiring board 1 as shown in FIG. Printing can be performed by reaching it. The non-charged ink particles 10 travel straight and are received by the gutter 15 and do not adhere to the printed wiring board 1. The ink particles 10 received by the gutter 15 are collected in the ink reservoir 17 and reused after being regenerated by stirring or adjusting the viscosity. Printing can be performed by fixing the nozzle 11 of the inkjet printer and moving the printed wiring board, but a method of moving the nozzle 11 may be used. Further, when high-speed printing (printing) is required, a multi-nozzle system in which a plurality of nozzles 11 are provided in parallel can be adopted. It is preferable to cover the area from the nozzle 11 to the surface of the printed wiring board 1 to be printed so that the flight of the ink particles 10 is not affected by the flow of air, but the ink attached to the printed wiring board 1 is dried. 5 to 1000 cm / sec of air rectification to speed up and prevent bleeding and repelling
Sending at moderate wind speed is effective. In the present invention, the ink jet printer is not limited to the above-described charge deflection type ink jet printer, but may be a bubble jet type, a static control type, a drop-on-mind type ink jet printer, or the like. ..

Claims (3)

[Claims] 1. A method for printing on a printed wiring board, which comprises providing a circuit protective film containing an inorganic ion exchanger on the surface of the printed wiring board, and printing on the surface of the circuit protective film by an inkjet printer. 2. The printed circuit board according to claim 1, wherein the circuit protective film is formed by applying a liquid solder resist containing an inorganic ion exchanger onto the surface of the printed circuit board. Method. 3. The circuit protective film is formed of two layers, a lower film layer and an upper film layer, and one of the lower film layer and the upper film layer contains an inorganic ion exchanger. Item 3. A method for printing on a printed wiring board according to item 1 or 2.