JPH02234308A - Composition for conductive film formation - 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 [Field of Industrial Application] The present invention mainly relates to a composition for forming a conductive film used for forming conductive circuits and electrodes on an electronic component insulating substrate, particularly an AIN substrate.

[Conventional technology]

Alumina substrates with conductive films formed on them are often used in electronic component circuits.

To form a conductive film on such an insulating substrate, generally conductive powder such as Ag, Pd, or Pt, lead borosilicate glass powder to provide adhesion to the substrate, and bismuth oxide are used. A paste-like composition is prepared by dispersing the solid powder mixture contained in an organic vehicle, and this paste-like composition is applied onto a substrate by a screen printing method or a transfer method,
It is fired to form a conductive film.

With the miniaturization of electronic circuits, klH substrates with good thermal conductivity are being used in place of alumina substrates. There are problems such as not adhering to the IN board or not adhering solder.

[Issues that Hatsurou tries to solve]

The main object of the present invention is to provide a composition for forming a conductive film that has good adhesion to an IN substrate and good solder wettability.

[Means to solve the problem]

The present invention provides a conductive film forming composition comprising a solid powder mixture containing noble metal powder and glass powder dispersed in an organic vehicle, in which vanadium oxide is added as the glass powder component to vanadium pentoxide in the solid powder mixture. A means for solving the problem is a composition for forming a conductive film characterized by containing 0.5 to 6% by weight of glass powder and 2 to 7% by weight of glass powder.

The noble metal powder used in the present invention includes Ag, Pd, and Pd.
tSAu etc. can be used, and these may be used alone or in a mixture, or as an alloy powder.

The amount of precious metal powder in the solid powder mixture is generally about 73
~98% by weight.

The glass powder is present in the solid powder mixture in an amount of 2-7% by weight, 4-7% by weight.
A blending amount of 6% by weight is good. Glass powder is obtained by melting a mixture of vanadium oxide, silicon dioxide, boron oxide, zinc oxide, aluminum oxide, barium oxide, strontium oxide, calcium oxide, lead oxide, etc., cooling it, vitrifying it, and pulverizing it. I can do it.

In addition to the noble metal powder and glass powder, an inert filler can also be blended. Examples of the inert filler include pigments such as bismuth oxide, manganese oxide, steel oxide, cobalt oxide, molybdenum oxide, zinc oxide, and chromium oxide, which may be used alone or in combination. Inert fillers may be absent from the solid powder mixture, but can be incorporated up to as much as 20% by weight.

The particle size of the solid powder mixture is preferably 10 μm or less, preferably 2 μm or less.

As the organic vehicle, conventionally used organic vehicles in which ethyl cellulose, methacrylate resin, etc. are dissolved in a solvent such as terpineol, butyl carbitol, or toluene can be used.

The composition of the present invention is prepared by adding 100 parts by weight of a solid powder mixture and 11 to 10 parts of an organic vehicle using a three-roll mill as in the past.
35 parts by weight.

The substrate to which the composition of the present invention is applied is not limited to A7N, but substrates having a thermal conductivity of 100 to 260 W/mK and a thermal expansion coefficient of 35 to 45×10 /σ are suitable.

[Effect]

In the present invention, the acid content in the solid powder mixture of glass powder is set to 2 to 7% by weight, because if it is less than 2% by weight, it will not work as an adhesive to the substrate and the adhesive strength will be low. This is because if it exceeds 7% by weight, solder wettability will deteriorate.

Furthermore, the reason why vanadium oxide is contained as the glass powder in the solid powder mixture is 0.5 to 6% by weight in terms of vanadium pentoxide because if it is less than 0.5% by weight, the adhesive strength to the substrate will be insufficient. This is because if it exceeds %, the edges of the spread film will bleed when fired to form a film, making it easy to cause short circuits.

〔Example〕

As glass powder, V O , SiO , ZnO, E
O, 2B 2
After blending 23Pk+O, klOs BaO, etc. in the proportions shown in Table 1 and melting at 900 to 1500σ,
The precious metal powders include Ag powder with a particle size of 1.2 μm and P(L powder with a particle size of 0.1/jm). , M as an inert filler
nO s Bi O and OuO were prepared.

Turbineol containing 8% by weight of ethyl cellulose was prepared as an organic vehicle.

Noble metal powder, glass powder, and inert filler powder were mixed in the proportions shown in Table 2 to prepare 19 types of solid powder mixtures.

100 parts by weight of the solid powder mixture and 20 parts by weight of the organic vehicle were kneaded in a three-roll mill to form a paste.

Commercially available pastes for alumina substrates as shown in Table 3 were also tested.

Paste each of the above onto a ktN board (25X25X
0. After screen printing a predetermined pattern on the surface of 625 ms), the peak temperature was 850
C', firing was performed in an air atmosphere with a peak time of 8 minutes and a total firing time of 60 minutes.

The obtained conductive film was measured for solder wettability, adhesive strength, aging strength, and oozing. The respective measurement methods are as follows.

(1) Solder wettability 7 lux was applied on a conductive film pattern of 1Qms square, and after removing the oxide film on the surface, the pattern was
Pb-Sn kept at σ (Pb/Sn = 37
/6.3) Immerse it in a solder bath for 5 seconds, pull it out, and after cooling, determine the solder wet area ratio on the pattern.

(2) S with a diameter of 0.65 on a pattern of conductive backing with an adhesive strength of 2 and an angle of 2.
An n-plated copper wire is soldered with Pb-Sn solder, the copper wire is pulled in the vertical direction, and the tensile force at the time of peeling is determined.

(3) S with a diameter of 0.65 on a conductive film pattern with an aging strength of 2 cod angles
Solder the n-plated @ wire with Pb-Sn solder, 150σ
After being left in a constant temperature bath for 300 hours, the tensile force similar to the adhesive strength was determined.

(4) Observation of oozing When the glass component in the conductive coating leaches from the patterned area to the area where the conductive coating is not attached, a brownish coloration occurs on the substrate, so this condition is observed with the naked eye.

The above measurement results are shown in Table 4.

Solder wettability is 80% or more, adhesive strength is 4.Qlcg or more, and aging strength is 2. Since the product is required to have an OJC of 9 or higher, the passing values are marked with a circle, and the failing values are marked with an x.

Test blacks 1 to 13 of the present invention passed all of the above characteristics, but comparative examples AI4 to 19 failed in any of the characteristics, and commercially available base products for alumina substrates A, B, and O products Although no oozing was observed, all characteristics failed.

Table 1 (wt%) Table 2 (wt%) [Effects of the Invention] According to the present invention, it is possible to provide a composition for forming a conductive film suitable for an AIN substrate or a substrate having physical properties similar thereto.

Out wish Man Sumitomo Metal Mining Co., Ltd. hand control Supplementary Positive book (spontaneous) (I.J. 3 lines from the bottom of page 4 of the specification, 6 lines from the bottom of page 5, 7 lines from the bottom of page 6, 7 pages, 4 lines, 6 from below line in each row "C゜" of lfJ I am corrected.

l. Display of incidents Heisei Year Special permission wish No. issue name of invention Composition for forming conductive film λ Person who makes corrections Relationship with the incident

Claims (1)

[Claims] (1) In a conductive film forming composition comprising a solid powder mixture containing noble metal powder and glass powder dispersed in an organic vehicle, vanadium oxide is added as the glass powder component to vanadium pentoxide in the solid powder mixture. A composition for forming a conductive film, characterized in that it contains 0.5 to 6% by weight of glass powder and 2 to 7% by weight of glass powder.