JPS61114403A - Composition for metalization - 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 (Industrial Field of Application) The present invention relates to a metallizing composition for forming a metallized metal layer on a ceramic body, and more specifically, to a metallizing composition for forming a metallized metal layer on a ceramic body, and more specifically to a metallizing composition for forming a metallized metal layer on a ceramic body. The present invention relates to a metallizing composition used for forming a metallized metal layer.

(Conventional technology) Conventionally, ceramics have excellent properties such as electrical insulation and chemical stability, so they have been widely used in electronic components such as puff cages that house semiconductor devices and circuit boards with circuit wiring. A metal rice layer to which external lead terminals are brazed is formed on the surface of the ceramic body.

The metallized metal layer on the surface of such a ceramic body is usually
An organic binder and an organic solvent are added to high-melting point metal powder such as tungsten (W) and manganese (Mn), and a paste is formed onto the surface of the raw ceramic body by screen printing, and then the raw ceramic body is coated. The metallized metal layer is manufactured by sintering it in a recessed atmosphere and sintering and integrating the high-melting point metal and the ceramic body. (Ni) plating is applied.

(Problem to be solved by the invention) However, the surface of this conventional metallized metal layer using tungsten (W) or the like is plated with nickel (N1) to improve wettability with the brazing material. In this case, the ceramic body cannot be plated directly and the circulation of the plating solution is poor, so the side surface of the metallized metal layer is
The nickel plating layer cannot be deposited in the vicinity of the ceramic body surface, and a slight gap is formed between the nickel plating layer and the ceramic body surface. Therefore, when moisture, etc. contained in the atmosphere adheres to a part of this gap, the moisture comes into contact with the metallized metal layer and the nickel plating layer and acts as an electrolyte. Due to the difference in energy levels, a current flows, causing a S:pool action, and as a result, the metallized metal layer with a low energy level is gradually eluted by 1ζ due to this battery action, which may discolor the surface of the metal layer. In addition, in electronic components where a large number of external lead terminals are brazed in close proximity, adjacent external lead terminals may short-circuit or the metallized metal layer may be disconnected due to elution of the pre-formed metallized metal layer. This causes a serious drawback in that it interferes with the function of the electronic component.

(Object of the Invention) In view of the above-mentioned drawbacks, the present inventor has conducted various experiments and found that molybdenum (M
When o) is contained in an amount of 50% by weight or more, the metallized metal layer formed by the metallizing composition has an energy level similar to that of the plated metal layer, and the metallized metal layer and the plated metal layer are free from moisture. It has been found that even if the metallized metal layer adheres, it is effectively prevented from being eluted by the action of the battery.

Based on the above findings, the present invention has been developed to firmly braze external lead terminals, etc., without any elution of the metallized metal layer that would cause discoloration or impede the function of electronic components even if moisture contained in the atmosphere adheres. The object of the present invention is to provide a metallizing composition capable of forming a metallized metal layer.

The metallizing composition of the present invention is an electronic component having an external lead terminal, specifically tζ is a wiring board for a hybrid IC,
It is suitably used for forming a metallized metal layer to which external lead terminals of IC packages and the like are brazed.

(Means for Solving the Problems) The metallizing composition of the present invention is composed of tungsten and molybdenum, and is characterized in that the content of molybdenum is 50% by weight or more.

(Example) Next, the present invention will be explained based on examples.

Tungsten (W) with particle size 1~5Bms as starting material
and molybdenum (MO) were weighed as shown in the table below, an organic binder and a solvent were added thereto, and the mixture was kneaded for 10 hours using a mixer to obtain a metallizing paste sample.

Note that sample number 9 is a comparative sample for comparison with the product of the present invention, and is a metallizing paste that has been conventionally used for transportation.

Using the thus obtained metallizing paste sample, 50 patterns of length LOa, width 1.3a+, and thickness 2Q pry were printed at intervals of 1.4 al on the surface of a raw ceramic body made of alumina, and then these were printed. was fired at a temperature of about 1600° C. in a reducing atmosphere (nitrogen-hydrogen atmosphere) to deposit a metallized metal layer on the surface of the ceramic body, and the surface of the metallized metal layer was plated with nickel to a thickness of L5 μm. And the next one is 8 fl in length, 1 ff in width,
One end of the external lead terminal made of 0.25 Al (D 42 A11oy) was soldered with silver solder (Ag 72%, Ou
28%), and while applying a voltage of 17 (1+') between each external lead terminal,
-24 temperature and humidity cycle tests specified in 883-1004
After 0 hours (10 cycles), the surface of the nickel plating layer was observed using a microscope to determine the number of discolored surfaces.

At the same time, measure the insulation resistance between each external lead terminal,
The average value was calculated.

The initial value of the insulation resistance between the external lead terminals is 5X1.
It was set to 0 (Ω).

The above results are shown in the table below.

Items marked with an O are outside the scope of the present invention.

(Effects of the Invention) As can be seen from the above experimental results, 1) the metallized metal layer using the conventional metallizing composition has a discoloration rate of 94% due to elution of the metallized metal layer, and an insulation resistance between external lead terminals. In contrast, in many cases, the metalla tungsten surface of the present invention decreases to 10 to 30% by weight and molybdenum (MO) 70 to 90% by weight.
A metallized metal layer using a metallized composition consisting of the following is suitable as a metallized composition for forming a metallized metal layer, as there is no discoloration due to elution of the metallized metal layer, and there is little deterioration in insulation resistance.

Therefore, the metallizing composition of the present invention is suitable for electronic components 1.
It is extremely useful for forming metallized metal layers to which external lead terminals are brazed.

Claims (2)

[Claims] (1) A metallizing composition comprising tungsten and molybdenum and having a molybdenum content of 50% (wt%) or more. (2) The metallizing composition according to claim 1, comprising 10 to 30 (wt%) tungsten and 70 to 90 (wt%) molybdenum.