JPS60157291A - Method of forming semiconductive circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for forming a semiconductive circuit by printing a required wiring diagram using a semiconductive composition.

[Background of the invention]

In electronic equipment wiring, the wiring layout is lighter and lighter.
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Because of this, printed wiring boards have come into widespread use. In such printed wiring boards, all or part of the wiring circuit is often printed with a semiconductive composition to form a conductive circuit or a resistive circuit. Conventionally, the paints used for these have mainly been based on chemically reactive resins that harden at room temperature or by heating. When a printed circuit is cured at room temperature or under heat, it takes several tens of minutes to several hours to cure, which makes it difficult to speed up the coating process and to make the equipment assembly line continuous and rational. Furthermore, in cases where the substrate is made of a material that is not heat resistant, the curing conditions for the coating film are often restricted because the circuit deforms. Further, when forming a circuit after assembling electronic components, some electronic components change in quality when heated to high temperatures, so in this case as well, there are restrictions on the curing conditions of the coating film.

Recently, in order to solve these problems, instead of the conventional semiconductive paint that is based on a chemical reaction between a base agent and a curing agent, a semiconductive paint film has been formed using an electron beam or ultraviolet curable paint. This is starting to be considered. The present inventors have also proceeded with studies on semiconductive paints that can be cured by electron beams or ultraviolet rays. Electron beam or ultraviolet curable paints can be rapidly cured by irradiation with electron beams or ultraviolet rays, so they can be expected to streamline the manufacturing process.

Now, a semiconductive paint is a resin base in which conductive particles such as carbon black are dispersed. Therefore, it has been thought that even if an attempt is made to cure this with ultraviolet rays, the light is blocked and the energy does not reach the interior, resulting in insufficient curing and failure to form a good coating film. With electron beam curing, there is no problem with curing, and the effects of speeding up curing and streamlining the process are not impaired, but if it is used on a device assembly line, expensive irradiation equipment is required, and ultraviolet irradiation is Maintenance and management are also more complicated than equipment.

Furthermore, when forming a circuit after assembling electronic components, there is a risk that the electronic components may be damaged by the electron beam.

In order to solve this problem, we conducted intensive research on a method of curing printed circuits by irradiating them with ultraviolet light. As a result, among a large number of UV-reactive resins, in particular, a composition consisting of a resin base containing a UV-functional Lewis acid salt and an epoxy resin as a main component, and adding carbon black or graphite to this resin base. Although it was predicted that by printing a circuit and irradiating the circuit with ultraviolet rays, the addition of carbon black or graphite would block the incidence of ultraviolet rays inside the coating, it was strange. In particular, we discovered an unexpected phenomenon in which circuits can harden to the inside.

[Summary of the invention]

The present invention was made based on the above findings, and
Its gist is that a circuit is printed using a composition containing as main components an epoxy resin, ultraviolet-functional Lewis hydrochloric acid, and carbon black and/or graphite, and the circuit is cured by irradiating ultraviolet light. A method for forming a semiconductive circuit.

[Detailed description of the invention]

The resin base serving as the paint base used in the present invention is composed mainly of an epoxy resin and an ultraviolet-functional Lewis acid salt. Here, the ultraviolet-functional Lewis acid salt refers to one that generates a Lewis acid that causes cationic polymerization of an epoxy resin upon irradiation with ultraviolet light. The epoxy resin and Lewis acid salt may be mixed at the time of preparing the paint, or may be mixed immediately before printing.

As the epoxy resin, conventionally known glycidyl ether type or alicyclic epoxy resins are used. Examples of Lewis acids include PF5 and BFs, and examples of their salts include Lewis acid diazonium salts (e.g. p-methoxybenzenediazonium hexafluorophosphate-1-), Lewis acid iodonium salts (e.g. Eva, diphenyl Iodonium hexafluorophosphate-1-), Lewis acid sulfonium salts (eg, Eva, triphenylsulfonium hexafluorophosphate), and the like. In other words, commonly used photosensitizers such as carbonyl and nitrogen-containing types are added to the paint haze to enhance UV functionality.

In the present invention, carbon black or graphite is used alone as the conductive particles, or carbon black and graphite are used in combination. As the carbon black, furnace black, aretylene black, etc., which are usually used in the production of semiconductive paints, are used. Graphite may also be one normally used in the production of semiconductive paints, but scaly graphite with a particle size of about 01 to 50 μm is preferable.

In the semiconductive paint used in the present invention, 10 to 100 parts by weight of carbon black and/or graphite are added to a total of 11:100 parts by weight of epoxy resin and Lewis acid salt. If the amount added is less than 10 parts by weight, sufficient semiconductivity can be achieved by 1! I can't do anything but
Furthermore, if the amount added exceeds 1.00 parts by weight, the semiconductivity will be good, but the coating workability will decrease and the finished state of the circuit will tend to deteriorate111. Particularly preferably, the average particle size is 30 to 50 mff.
In the case of acetylene black of about 10 to 4
0 parts by weight, 10 to 30 parts by weight in the case of conductive furnace black with an average particle size of about 20 to 40 μm,
In the case of scaly graphite with an average particle size of about 1 to 5μ, 2
0 to 60 parts by weight, and 20 to 50 parts by weight in the case of a mixture of acetylene black with an average particle size of about 30 to 50 μm and scale graphite with an average particle size of about 1 to 5 μm.

In the present invention, other silicone compounds, fatty acid esters, amine compounds,
It is also possible to add viscosity adjusting materials such as surfactants. A composition can be prepared by adding carbon black or graphite to a resin that serves as a paint base, by the usual method of preparing a paint, for example, by thoroughly and uniformly kneading it by roll mixing. Methods for applying the semiconductive coating composition include application using a brush or roller, screen printing, and the like.

The printed circuit is cured by exposing it to ultraviolet light.

As for the ultraviolet irradiation conditions, it is desirable to use an ultraviolet lamp with a power of about 50 to 200 W/cm and to perform the irradiation for about 10 to 60 seconds. After curing the printed circuit by irradiating it with ultraviolet rays, the temperature should be kept at 80 to 200°C as long as it does not damage the substrate or electronic parts, etc., in order to allow the curing to proceed more fully.
The heat treatment may be performed at a temperature of 5 to 60 minutes.

Example 1 Abka Ultracera 1-AD7200 100 1 part by weight (epoxy resin product name of Asahi Denka Kogyo Co., Ltd.) Curing catalyst PP33 3-fold loss part Acetylene black 15 parts by weight were kneaded with three rolls to form a paint. Created. This paint was screen printed to a thickness of 30 μm on a 50 μm thick polyimide film to form a semiconductive printed circuit.
It was cured by irradiating it with ultraviolet light for 30 seconds using two KW ultraviolet lamps. After curing, the printed wiring board was immersed in methyl ethyl Kent for 5 minutes.

After taking it out, the coating film was rubbed vigorously, but no abnormality occurred in the coating film, and it was confirmed that curing had progressed well to the inside of the coating film. When the conductivity of the circuit was measured, it was 103 to 104.
It was found that the resistance value was on the order of Ω.

Example 2 A copper foil was pasted on the surface of a glass cloth/epoxy resin laminate, a circuit was formed by etching, and the circuit was printed at the desired position on the printed wiring board using the paint prepared in Example 1. , and was cured under the same conditions as in Example 1 to form a required resistance circuit.

Comparative Example 1 In Example 1, the composition of the paint was changed to 80 parts by weight of Aroex oligomer, 80 parts by weight of Lipokine resin, VR-8020 parts by weight, photosensitizer, 5 parts by weight of benzyl dimethyl ketal, and 15 parts by weight of acetylene black, and the other parts were the same as in Example. A semiconductive circuit was created under the same conditions as 1. The surface of the coating film was well cured, but when the coating film was rubbed after being immersed in methyl ethyl Kent, the coating shifted from the base film, indicating that the coating had not been sufficiently cured to the inside.

As mentioned above, in the method for forming a semiconductive circuit according to the present invention, a circuit is printed using a composition made of a Lewis acid-reactive ultraviolet curable epoxy resin to which carbon black or graphite is added. Since it is cured by irradiation with ultraviolet rays, the circuit formation process is extremely simple, and the circuit formation and device assembly lines can be made continuous and rational.

Continued from page 1 0 Inventor Noriko Matoba Chikuma-sho, Nishiyodoyo-ku, Osaka City

Claims (1)

[Claims] (1) A semiconducting device characterized by printing a circuit with a composition containing as main components an epoxy resin, an ultraviolet-functional Lewis acid salt, and carbon black and/or graphite, and curing the circuit by irradiating it with ultraviolet rays. How the sexual circuit is formed.