JPS62200703A - Manufacturing method of printed resistor - 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 [Object of the Invention] (Field of Industrial Application) The present invention relates to a method of manufacturing a printed resistor. More specifically, 5 the present invention prints an electron beam curing resistor paste in a predetermined shape between electrodes fabricated on a base material surface such as a substrate of a printed wiring board, and then irradiates the electron beam to The present invention relates to a method of manufacturing a printed resistor by curing a resistor paste.

(Prior art) Conventionally, methods for forming resistors by printing in the manufacturing process of printed wiring circuits or hybrid thick film circuits have been made using resistor pastes mainly composed of metal oxides such as ruthenium oxide and glass frit, or carbon A resistance paste (hereinafter referred to as carbon-based resistance paste) mainly composed of carbon-based fine powder such as a blank, a thermosetting resin binder, and an organic solvent is placed between the electrode parts prepared in advance on the substrate. After printing on the shape,
A method of producing a resistor by heating and firing at a high temperature was known. Among these pastes, carbon-based resistance pastes have a lower firing temperature (120 to 200°C) than resistance pastes whose main components are metal oxides and glass frit.

It's cheap. For these reasons, it is widely used as a printed resistor for organic substrates.

It is also used in electrode parts for membrane contacts such as keyboard switches.

However, these carbon-based resistance pastes.

(1) Since it is necessary to heat the substrate to 120-200°C for several minutes, the heat resistance of the substrate is limited, energy consumption during heat curing is large, and production efficiency is poor because heat curing takes a long time. (2) Since the resistor paste contains a solvent, the resistor paste is treated as a dangerous substance and is difficult to handle. (3) There were drawbacks such as the process of evaporating the F4 agent and recovering it and the large amount of energy consumed therein.

As a method to improve these drawbacks, a method has been proposed in which a resistance paste consisting of carbon-based fine powder and an ultraviolet curable resin binder and containing no organic solvent is cured by ultraviolet irradiation. However, in these methods, (1
) Only the surface of the printed resistance paste is cured, and the inside is not sufficiently cured. (2) Since it is solvent-free, it is not possible to increase the blending ratio of carbon-based fine powder to the binder, resulting in low resistance values. There were drawbacks such as the inability to obtain a resistance paste.

As a method for improving these drawbacks, a method has been proposed in which a resistance paste made of carbon-based fine powder and an electron beam-curable resin binder and containing no organic solvent is cured by electron beam irradiation. Although these methods improve the drawback of not curing to the inside.

Since it is solvent-free, it is not possible to increase the blending ratio of carbon-based fine powder to the binder, and the drawback that a resistance paste with a low resistance value cannot be obtained cannot be solved.

On the other hand, it is possible to adjust the resistance value of a printed resistor using a carbon-based resistance paste or a resistance paste consisting of an ultraviolet/electron beam curable resin binder and carbon-based fine powder.

This is usually done by the following means.

(1) Adjustment of the resistivity of the resistance paste itself (in particular, adjustment of the blending ratio of carbon-based fine powder and binder resin) (2) Adjustment of printed film thickness and printed shape (3) Adjustment of curing and firing conditions (4) Curing Trimmed printed resistors after firing are required to have resistance values in an extremely wide range from several Ω to several MΩ. For this purpose, the above measures (2) to (4) or a combination thereof are not sufficient; it is necessary to prepare a large number of series of resistance pastes having various specific resistances, and there are manufacturing and (Problems to be Solved by the Invention) The inventors of the present invention encountered problems during research on manufacturing printed resistors by electron beam curing before and during electron beam irradiation.

Alternatively, by adding a heating process after irradiation, the resistance value of the printed resistor after curing is significantly reduced, and the degree of reduction can be freely controlled by controlling the heating temperature and time.2 The present invention The present invention improves the various drawbacks mentioned above.

It can be cured at low temperatures and in a short time, and even if the resistance paste has the same composition, it is possible to obtain printed resistors with a wide range of resistance values with good reproducibility by adjusting the heating temperature and time.Moreover, it is solvent-free. The purpose of the present invention is to provide a method for manufacturing a printed resistor that can obtain a printed resistor with an extremely low resistance value.

[Structure of the invention]

(Means for solving the problem) The present invention prints an electron beam curing resistive paste on a base material,
After removing the solvent if necessary, the printed resistor paste is cured by irradiation with an electron beam to produce a printed resistor. A method for manufacturing a printed resistor, characterized in that the printed resistor paste is heated before, during, or after irradiation.

In the present invention, the base material is 1 paper-phenol resin,
Resin laminates made of glass base cloth-epoxy resin paper-polyester resin, flexible substrates made of polyimide, polyester, etc., and ceramic substrates.

Any substrate commonly used in the electronics industry, such as an insulating coated metal substrate, can be used.

In the present invention, as the electron beam curable resistance paste, a paste whose main components are carbon-based fine powder and an electron beam curable resin binder is used.

Examples of carbon-based fine powder include 1, for example, acetylene blank,
Fine carbon black powder such as furnace black, thermal black, and channel black.

One type or a mixture of two or more types selected from carbon black fine powder obtained by graft polymerization of a vinyl monomer, carbon blank fine powder subjected to oxidation treatment, and graphite carbon fine powder is used.

Examples of the electron beam curing resin binder include 2.

Electron beams for unsaturated polyesters, polyester (meth)acrylates, epoxy (meth)acrylates, polyol (meth)acrylates, polyurethane (meth)acrylates, polyether (meth)acrylates, allyl compounds, divinyl compounds, etc. One type or a mixture of two or more types selected from among the reactive compounds is used. In addition to the above two components, the electron beam curable resistance paste contains metal powder, metal oxide powder, inorganic powder, and other nonvolatile additives.

It may also contain volatile solvents. After mixing these components, the electron beam curable resistive paste according to the present invention can be easily obtained by the method 1 used in the production of ordinary pastes, such as passing through a three-roll device.

The electron beam curing resistor paste is printed in a desired thickness and shape between electrodes provided on a base material. The electrodes are usually copper foil left by etching, but I! The electrode may be formed by a conductive paste made of powder or the like, a so-called thin film method, or an additive method. Printing is usually carried out by screen printing, but the printing method in the present invention is not necessarily limited to this.

After printing, if the electron beam curing resistor paste contains a volatile solvent, the solvent is removed and the printed resistor paste is then irradiated with an electron beam in air or an inert gas atmosphere. hardened. The conditions for electron beam irradiation are an acceleration voltage of 150 to 300 KV and an irradiation dose of 3 to 30 KV.
It is desirable that the oxygen concentration in the irradiation atmosphere be 500 ppm or less.

In the present invention, by heating the printed resistive paste before, during or after irradiation with the electron beam, after printing and if necessary removing the solvent.

The resistance value of the resulting printed resistor can be significantly reduced, and the degree of reduction can be freely controlled by heating temperature and time. Printed resistors with various resistance values can be obtained with good reproducibility even if the trimming processing conditions are the same.

Moreover, it is also possible to obtain a printed resistance with an extremely low resistance value.

As described above, the reasons why the resistance value of the obtained printed resistor decreases significantly by heating before, during, or after electron beam irradiation are changes in the carbon-based fine powder,
Possible causes include changes in the binder resin, changes in the agglomerated orientation of the carbon-based fine powder due to changes in the interface between the carbon-based fine powder and the binder resin, or changes in the contact state between the resistance paste and the electrode surface. However, the details are not clear at this stage.

Heating may be done before, during, or after electron beam irradiation, or by an appropriate combination of these, but heating before electron beam irradiation will reduce the resistance value. It is most effective against

Possible means for heating include heating with hot air, heating with infrared rays, dielectric heating, etc., but heating with infrared rays is the most effective from the point of view of minimizing dimensional changes in the substrate due to heating. Conditions for proper heating depend on the size of the substrate, but the general outline is as follows.

For heating with hot air: 80 to 120°C, 20 minutes to 60 minutes
In the case of infrared heating: The resistance paste that has been subjected to heat treatment for 30 to 60 seconds and electron beam irradiation treatment can be subjected to trimming treatment or coating treatment with an insulating film in a subsequent step, if necessary.

(Example) The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited in any way by these Examples. In the examples, 9 parts represents parts by weight.

Example 1 A binder having the following composition and carbon-based fine powder were mixed and then kneaded using three stainless steel rolls to obtain a resistance paste.

Trimethylolpropane triacrylate 14.3 parts Polyester diacrylate (manufactured by Nippon Shokubai Chemical Industry Co., Ltd.,
0E-A410) 35.7 parts epoxy diacrylate (manufactured by Kyoeisha Yushi Kagaku Kogyo.

80MFA) 21.4 parts Furnace black (manufactured by CABOT, UK-VULCA
NP, average particle size 20 nm) 2
．． 9 parts acetylene black (manufactured by Denki Kagaku Kogyo ■, Denka Black, average particle size 40 nm)
2.9 parts graphite (made by resident aluminum smelting side,
POG-10, average particle size 2.7μm)
22.9 parts of the obtained resistance paste was printed using a 200 mesh nylon screen plate onto a single-sided copper-clad paper phenol laminate on which a copper foil electrode portion had been previously prepared by etching and polishing. The size between the copper foil electrodes of the printed resistance paste was 4 mm horizontally and 4 square meters high. The resistance paste was cured using an electron beam irradiation device (manufactured by Energy Sciences, Model 150B-15).
Acceleration voltage 160KV, irradiation dose 1 in nitrogen gas atmosphere
This was carried out by irradiating an electron beam from the printed surface side under the condition of 0 Mrad. After printing.

IKW is used for heating before and after electron beam irradiation.
Using an infrared irradiation device (manufactured by Research, Fuuser-646 model) equipped with four infrared lamps (length: 30 CIl), irradiation was performed for 45 seconds from the printed surface side with a lamp-to-sample distance of 22. The surface temperature of the laminate at this time is approximately 130
It was °C.

Next, the resistance value between the copper foil electrodes was measured using a wide range digital ohmmeter DR-1000CU manufactured by Sansho Keiki Seisakusho, and was expressed in units of Ω10. Table 1 shows the resistance values obtained when infrared heating was performed before electron beam irradiation, when infrared heating was performed after electron beam irradiation, and when infrared heating was performed before and after electron beam irradiation. .

Comparative Example 1 Table 1 also shows the resistance values of a printed resistor obtained in the same manner as in Example 1 except that infrared heating was not performed.

Table 1 Example 2 A binder and carbon-based fine powder having the following composition were mixed and then kneaded using three stainless steel rolls to form a resistance paste.

Trimethylolpropane triacrylate 35 parts 2-
Hydroxy-3-phenoxyprobyl acrylate

Part 35 Furnace Black (CABO
Manufactured by T company, UK-VULCAN P, average particle size 20 n
m) 20 parts graphite (manufactured by Jusumi Aluminum Smelting and Refining, POG-10, average particle size 2.7 μm)
) 10 parts of this resistance paste was mixed with conductive silver paste (Silves 1-PS4 manufactured by Tokuriki Kagaku Kenkyusho).
07) was printed in the same manner as in Example 1 on a paper phenol resin laminate on which electrodes were formed by printing curing (using a 200 mesh nylon screen, curing by heating at 150°C for 930 minutes), and then drying in a hot air circulation dryer. using 80°
C, at a temperature of 100°C or 120°C for 30 minutes or 6
Heat treatment was performed for 0 minutes. Subsequently, the paste was cured by irradiation with an electron beam under the same conditions as in Example 1, and then the resistance value was measured. The results obtained are shown in Table 2.

Comparative Example 2 Table 2 also shows the resistance values measured in the same manner as in Example 2, except that no heat treatment was performed.

[Effects of the Invention] By the method for manufacturing printed resistors of the present invention, (1) printed resistors with various resistance values can be obtained freely and with good reproducibility from resistor pastes of the same composition, and many types of resistors can be produced unlike conventional methods. There is no need to make a resistance paste, and (2) even if the resistance paste is solvent-free, printed resistance can be obtained with an extremely low resistance value, and (3) it can be cured at low temperatures and in a short time.
By short-term heating with an infrared lamp, printed resistors can now be manufactured without damaging the substrate.

Claims (1)

[Claims] In the method for manufacturing a printed resistor, the printed resistor is manufactured by printing an electron beam curable resistor paste on a base material, removing the solvent if necessary, and curing the printed resistor paste by irradiation with an electron beam. and, if necessary, after removing the solvent, the printed resistor paste is heated before, during, or after irradiation with an electron beam.