JPH0367404A - Manufacture of conducting composition material and conducting circuit - Google Patents

Abstract

PURPOSE:To prevent the occurrence of worm-eaten hole-shaped defects and form a dense and uniform thin conducting layer by containing a material generating a specific quantity or more of dimethylsiloxane at the time of baking in a composition material containing metal powder, a binder and an organic solvent. CONSTITUTION:Glass powder 5 pts.wt. is added to spherical copper powder 100 pts.wt. to obtain a powder composition material. A vehicle such as acrylic resin and silicone resin 0.1-1.0 pts.wt. are added to it and kneaded, and butyl carbitol acetate is added to obtain the conductor paste with the viscosity suitable for screen printing. It is coated on an alumina board and baked in the nitrogen atmosphere at 900 deg.C for 10min. Dimethylsiloxane 100ppm or above is generated in the baking atmosphere, thus adequate coagulation among metal grains is suppressed, no worm-eaten hole-shaped defect is generated on a conducting layer with the thickness 5mum or below, and the dense and uniform layer can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a conductive composition suitable for forming a conductive layer on ceramics and a method for manufacturing a conductive circuit.

[Conventional technology]

One of the methods for manufacturing high-definition hybrid integrated circuits is to form a circuit pattern by etching using photolithography [Toshio Ogawa et al.
Microelectronics conference
ce) 1988 Proceedings, 194~
200 pages].

This method can be roughly divided into the following four steps.

■ The process of applying conductive paste onto a ceramic substrate and drying it to form a conductive layer.

(2) A step of forming a desired pattern on the conductive layer using a photosensitive resist.

(2) A step of removing unnecessary portions of the conductive layer by etching.

■ A step of removing the resist.

In order to form a high-definition pattern using the above method, it is required to form a thin, dense, and homogeneous conductor layer.

For example, in order to obtain a pattern with both line width and line spacing of 40 μm, the thickness of the conductor layer is required to be 5 μm or less and a dense film is required. If a dense film can be obtained, the film thickness can be reduced and a highly precise pattern can be obtained.

[Problem to be solved by the invention]

When attempting to form a conductive layer of metal such as copper with a thickness of 5 μm or less on a ceramic substrate, the metal particles locally agglomerate during the firing process, leaving the formed conductive layer as if eaten by insects. There is a problem in that so-called "worm-eaten defects" are generated, making it impossible to form a dense and homogeneous conductive layer.

In addition, as a means to suppress such excessive agglomeration of the metal particles, it may be possible to lower the firing temperature, but in this case, the reaction between the ceramic substrate and the binder in the conductive layer would be insufficient, making it practical for practical use. There was a problem that sufficient adhesive strength could not be obtained.The purpose of the present invention is to provide a conductive composition and a method for manufacturing a conductive circuit that can form a dense and homogeneous conductive layer even with a film thickness of 5 μm or less. .

[Means to solve the problem]

The present invention involves adding 11% dimethylsiloxane to a composition containing metal powder, a binder, and an organic solvent in the firing atmosphere by heating during firing.
00pp or more (more preferably 200 to 101000p
A conductive composition characterized by containing a substance that generates p,
In addition, in the method for manufacturing a conductive circuit in which a circuit pattern is formed using a conductive paste on a ceramic substrate and fired in a firing furnace, the atmosphere in the firing furnace contains dimethylsiloxane of 1100 pp or more (more preferably 200 to 101000 pp). A method for manufacturing a conductive circuit characterized by:

It is in.

The dimethylsiloxane achieves the object of the present invention by directly adding a substance that generates dimethylsiloxane to the conductive composition during firing of the conductive composition, or by introducing dimethylsiloxane into the atmosphere of the firing furnace. be able to.

As a result, even in a conductive layer with a thickness of 5 μm or less, the above-mentioned moth-eaten defects are not generated and the conductive layer is dense.

A homogeneous conductive layer can be formed.

By patterning the conductive layer using the photolithography method, a conductive circuit can be formed with a pattern accuracy of 40 μm or less in both line width and line spacing.

As the substance that generates dimethylsiloxane, dimethylsiloxane itself may be used, or silicone resin or the like may be used.

For example, in the case of silicone resin, the conductive composition 10
This is achieved by adding 0.2 to 4 parts by weight to 0 parts by weight.

Furthermore, by heating the silicone resin at the firing temperature of the conductive composition, it can be easily included in the firing atmosphere.

[Effect]

In the present invention, the reason why a dense and homogeneous conductive layer is obtained is that the added dimethylsiloxane acts on the surface of the metal particles forming the conductive layer and suppresses excessive aggregation of the metal particles with each other during firing. I think this is because there is.

Next, the present invention will be specifically explained using examples.

[Example 1] For 100 parts by weight (hereinafter simply referred to as parts) of three types of spherical mixed copper powders (weight ratio 1:1:1) with average particle diameters of 0.3 and 0.5.1 μm, Average particle size mainly composed of acid lead 1
．． A powder composition was prepared by blending 5 parts of 4 μm glass powder and mixing with a lysate machine.

The powder composition is coated with an acrylic resin (saniolated rli, 2C).
B-1)/Butyl carpitol acetate (1/3 part) of the vehicle and an appropriate amount of silicone resin (Shin-Etsu Chemical: X-62-7411) were added and kneaded at room temperature using three rolls. did.

Butylcarpitol acetate was further added to this to prepare a conductive paste with a viscosity of about 2000 cps suitable for screen printing.

The viscosity was measured using a Brookfield rotational viscometer at a rotational speed of 10 rpm and a temperature of 25°C.

Next, the conductor paste was applied by flexographic printing onto an alumina substrate provided with a glaze layer having a surface roughness of 0.2 μm or less, and dried at 120° C. for 10 minutes.

After repeating the printing process twice, it was fired at 900° C. for 10 minutes in a nitrogen atmosphere using a continuous belt firing furnace.

After baking, the surface was observed using a SEM microscope, and the wettability of the solder was evaluated by immersion in a solder bath (230° C., 5 seconds).

Note that the thickness of the conductive layer of this example after firing was about 4 μm.

Table 1 shows the results of the "presence or absence of moth-eaten defects" and "solder wettability" determined by the surface a test.

Table 1 As is clear from Table 1, when the amount of silicone resin added was 0.1 part or less, occurrence of moth-eaten defects was observed.

Furthermore, if 4.0 parts or more is added, the solder wettability is poor.

In addition, No. 3 has no occurrence of moth-eaten defects and has excellent solder wettability. No, 4 and No,
It was found that each of the samples in Example 5 had good adhesion strength between the ceramic substrate and the copper conductive layer. [Example 2] A photosensitive resist (Spray Fiber) was applied to the surface of the copper conductive layer of sample N004 of Example 1. East Company: S+1IPLE
Y FAREST Co.: AZ-1300
-31) was applied by a spin coating method and dried at 90°C for 30 minutes.

Next, a photomask was placed on the resist, patterned by irradiation with ultraviolet light, and developed for 2 minutes (Spree Far East: MF-TM312). washing with water,
120℃ after drying.

The resist was hardened by baking for 20 minutes, ion milling with an argon ion beam, and iodine/
By chemical etching with potassium iodide aqueous solution,
A conductive circuit was formed by removing the copper conductor from unnecessary parts of the circuit.

Next, through a series of steps of removing the resist with acetone, a copper conductive circuit having a minimum line width and line spacing of 40 μm was obtained.

No defects such as disconnection were observed in the circuit conductor. [Example 3] Using the conductor paste of sample No. 1 of Example 1,
A conductor 11M was formed under the same conditions as in Example 1.

However, during firing, by placing a ceramic substrate on which an appropriate amount of silicone resin is placed in a firing furnace and heating it together with the ceramic substrate forming the conductive 'U-', dimethylsiloxane is heated to about 50,100°200.400°. An atmosphere containing 1,000 and 2,000 ppm was created and fired in the atmosphere to form a conductive layer with a thickness of about 4 μm.

Note that the content of the dimethylsiloxane and the content in the atmosphere VB was measured by gas mass spectrometry and gas chromatography.

In the above, the above-mentioned defects were not observed in those having a concentration of 100 to 11,000 pp. On the other hand, those fired in an atmosphere containing about 50 ppm and 2000 ppm (7) dimethylsiloxane had the above-mentioned moth-eaten defects in the conductive layer.

In addition, the amount of dimethylsiloxane in the above atmosphere is 2
A range of 00 to 11,000 pp is more preferable [Effects of the Invention] The conductive composition of the present invention has the effect of suppressing excessive aggregation of metal particles during firing, and can easily form a high-definition conductor circuit. can. Further, by using the circuit board, it is possible to miniaturize and increase the density of electronic components.

Claims (3)

[Claims] 1. A composition containing a metal powder, a binder, and an organic solvent,
A conductive composition comprising a substance that generates 100 ppm or more of dimethylsiloxane in a firing atmosphere when heated during firing. 2. Composition 10 containing metal powder, binder, and organic solvent
An electrically conductive composition comprising 0.2 to 4 parts by weight of silicone resin per 0 parts by weight. 3. A method for manufacturing a conductive circuit, comprising forming a circuit pattern using a conductive paste on a ceramic substrate and firing it in a firing furnace, wherein the atmosphere in the firing furnace contains 100 ppm or more of dimethylsiloxane.