JPH0730442B2 - Deposition filament - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition filament used as an evaporation source heater during vapor deposition.

[0002]

2. Description of the Related Art In general, this type of vapor deposition filament is used for thermal vapor deposition of aluminum to vapor-deposit aluminum on an object to be vapor-deposited, for example, when manufacturing a semiconductor device. In this case, the vapor deposition filament is formed of a refractory metal such as tungsten, molybdenum, or tantalum. The vapor deposition filament types include the straight rod type shown in FIG. 3, the horizontal coil type shown in FIG. 4, the basket type shown in FIG. 5, and the hanging coil type shown in FIGS.

However, in both cases, when the amount of aluminum is large, the contact time with the molten aluminum becomes long. Corrosion generally occurs at the portion where the molten aluminum and the filament for vapor deposition are in contact with each other, and therefore the corrosion increases as the contact time between the molten aluminum and the filament increases. Therefore, few conventional filaments for vapor deposition can withstand repeated use in which the amount of vapor deposition is 0.5 g or more, and the number of repeated use is limited to 3 to 4 times.

Further, when the coil is energized to heat and evaporate the vapor deposition material loaded in the coil for a long time, the coil hangs down, and this hang-up does not return even after the coil is cooled. It was observed that the amount of sag increased further.

If the amount of sag as described above becomes too large, the evaporation of aluminum becomes nonuniform, and as a result, the vapor deposition on the object to be vaporized becomes nonuniform, which makes it unusable.
Further, when the coil is deformed, it becomes difficult to load the evaporation material. From this point as well, a coil that hangs as little as possible is desired.

From the above points, it has been attempted to add various additives to the heat-resistant alloy to reduce the sagging of the coil for the vapor deposition coil, and Japanese Patent Publication No. 54-15257.
By coarsening the crystal grains as shown in, it is recognized that the repeated use can be extended to a minimum of 5 times, a maximum of 18 times, and an average of 11 times.

Further, as shown in FIG. 2, a core metal (tungsten twisted wire) 3 is closely wound with an evaporation metal wire (Ni or the like) 4 and a partition metal wire 5 (Mo or the like), and a guard is further provided thereon. There is also one in which a wire (tungsten etc.) 6 is wound.

[0008]

When vaporized metal is attached to the vapor deposition coil shown in FIG. 2, the vaporized metal is filled in the gap between the two twisted wires 3 due to a capillary phenomenon, so that more vaporized metal is retained. You can Therefore, it is possible to increase the amount of evaporated metal vaporized per shot. For these reasons, the core body 3 often uses two or more stranded wires.

However, the stranded wire type filament is
There is a problem that twisting deformation and drooping phenomenon occur during energization of the filament due to processing strain generated in the twisted wire processing, and the life is remarkably reduced.

On the other hand, an attempt has been made to use a single wire type vapor deposition coil 7 as shown in FIG. 3 in order to eliminate processing distortion and the like. However, no matter how much evaporated metal is hung, there is no space to hold it. There is a problem in that most of it hangs down due to melting, and evaporation efficiency drops.

Further, the above-mentioned Japanese Patent Publication No. 54-15257,
It is described that the material in which the crystal is coarsened to remove the processing strain has an effect on the life.
Since the high temperature treatment of 500 ° C. or higher increases the running cost, there is a problem that deformation occurs when the strain is released.

Further, a horizontal coil type shown in FIG.
When the method described in the above-mentioned publication is applied to the basket type shown in Fig. 6 and the hanging coil type vapor deposition coil shown in Fig. 6 and Fig. 7, when the high temperature treatment is performed, the refractory metal which is the filament material is regenerated. Even if it crystallizes, it becomes brittle and becomes an irregular shape.

An object of the present invention is to increase the loading of aluminum by reducing the amount of aluminum that spontaneously drops due to vapor deposition, and to extend the life of the vapor deposition filament by eliminating sagging of the vapor deposition filament.

[0014]

According to the present invention, in a filament for vapor deposition using a refractory metallic core wire, a refractory metallic auxiliary coil wire is spirally wound on the outer peripheral surface of the core wire. The filament for vapor deposition characterized by being obtained is obtained.

Further, according to the present invention, there is provided a vapor deposition filament characterized in that the wire diameter of the auxiliary coil wire is 0.1 mm to 1.5 mm and the coil pitch of the auxiliary coil wire is 5 mm or less. can get.

[0016]

EXAMPLE A vapor deposition filament according to an example of the present invention will be described with reference to FIG. The illustrated vapor deposition filament is formed on the outer peripheral surface of a cylindrical tungsten single wire 1.
The auxiliary coil wire 2 made of tungsten is spirally wound.

Here, the linear shape of the tungsten single wire 1 is 2 mm.
Below, on the other hand, the wire diameter of the auxiliary coil wire 2 is from 0.1 mm to
1.5mm is desirable. The upper limit of the wire diameter of the auxiliary coil wire 2 is set to 1.5 mm because it is difficult to process if the upper limit is set to more than 0.1 mm. Is significantly reduced. Further, the auxiliary coil wire 2 is wound around the outer peripheral surface of the tungsten single wire 1 with a coil pitch of 5 mm or less, and by setting the coil pitch to 5 mm or less, the amount of retained evaporated metal can be increased.

Next, when the vapor deposition filament of the present invention was used, the number of times the filament could be used repeatedly until it melted and the number of times it was used, and the amount of sagging after repeating 10 times were measured. The measurement procedure will be specifically described below.

Sample 1 was prepared as an example of the conventional evaporation filament, and Sample 2 was prepared as an example of the evaporation filament according to the present invention. Of these, sample 1 has a wire diameter of 1.0 mm
3 is a filament (see Fig. 3) in which the tungsten wire of Fig. 3 is made into three strands. It is a spirally wound coil with a pitch of 2 mm (see Fig. 1). Here, the wire diameter of the sample 2 was set to 1.732 mm in order to set the wire diameter of the sample 2 so as to have the same cross-sectional area as the total cross-sectional area of the twisted wire of the sample 1 for the comparative experiment. That is, the wire diameter of the sample 2, which is equal to three times the cross-sectional area of the wire diameter of 1.0 mm, is 1.732 mm.

Both ends of the filaments of Sample 1 and Sample 2 were clamped to electrode portions (not shown), and the temperature was set to 1300 ° C.
The operation of holding for 60 seconds was counted once, and this was repeated, and the number of times the filament melted was measured. This measurement was performed several times, the number of times until each fusing was measured, and the minimum value, maximum value, and average value of the number of times were determined.

Next, after repeating the above operation 10 times for both the sample 1 and the sample 2, the amount of sag of each sample was measured.
In the measurement, the minimum value, the maximum value, and the average value of the sagging amount are obtained. The above measurement is the first measurement.

Further, a second measurement different from the above measurement is performed. As Sample 3, a horizontal coil type vapor deposition filament shown in FIG. 4 was used in place of the above-mentioned single-line vapor deposition filament. In this case, as the vapor deposition filament, a tungsten wire having a coil pitch of 2 mm and a wire diameter of 1.0 mm was made into three stranded wires. As in the case of the first measurement, as sample 4, a single tungsten wire having a wire diameter of 1.732 mm was used as a core wire, and an auxiliary coil wire of tungsten having a wire diameter of 0.5 mm was spirally wound at a pitch of 2 mm (not shown). No)
Was used. For these samples 3 and 4, the number of times until fusing and the amount of sag were measured by the same method as in the first measurement. Hereinafter, the results of the first measurement are shown in Table 1 and the results of the second measurement are shown in Table 2.

[0023]

[Table 1]

[0024]

[Table 2]

As can be seen from Tables 1 and 2, the tungsten single wire wound with the auxiliary coil wire (Sample 2, Sample 4) is the conventional evaporation filament (Sample 1, Sample 3).
As compared with the above, it can be seen that the minimum value, the maximum value, and the average value of the number of times until fusing are all about 3 to 4 times, and the drooping amount is also significantly reduced. Therefore, the loading of aluminum can be increased.

That is, in the conventional case, particularly when a stranded wire is used (see FIGS. 3 and 4), aluminum corrodes tungsten due to processing strain of the stranded wire, so that the life of the vapor deposition coil is shortened. On the other hand, even in the case of a single wire, since there is no gap for holding aluminum, a large amount of aluminum falls naturally and the evaporation amount becomes small.

In the case of the present invention, Sample 2 and Sample 4 have the same cross-sectional area as the total cross-sectional area of the twisted wires of Sample 1 and Sample 3.
In this case, since the wire diameters of the samples 2 and 4 are naturally larger than the wire diameters of the samples 1 and 3 per sample, the sample 2 and the sample 4 are It can be seen that it is stronger against deformation than Samples 1 and 3. or,
In Sample 2 and Sample 4, since the auxiliary coil wire is wound around the tungsten single wire, the retention and wettability of aluminum are the same as those of the stranded wire.

In the present invention, the auxiliary coil wire is simply a straight rod type (see FIG. 1) or a horizontal coil type (see FIG. 4).
However, it may be wound around a core wire of a type as shown in FIGS.

Further, although only tungsten is used as the material of the wound core wire used in the embodiments of the present invention, the material is not limited to tungsten, but may be a refractory metal material such as molybdenum, tantalum, niobium, or titanium. The same effect can be obtained.

[0030]

According to the present invention, by spirally winding an auxiliary coil wire around a core wire, it is possible to reduce the amount of aluminum that naturally drops due to vapor deposition. In this way, by reducing the amount of spontaneous fall, the loading of the vapor deposition metal can be increased, the sagging of the vapor deposition filament can be eliminated, and the life of the vapor deposition filament can be extended.

[Brief description of drawings]

FIG. 1 is a diagram showing the structure of a vapor deposition filament used in the present invention.

FIG. 2 is a view showing a structure of a conventional vapor deposition filament.

FIG. 3 is a view showing the structure of another conventional filament for vapor deposition.

FIG. 4 is a view showing the structure of another conventional evaporation filament.

FIG. 5 is a view showing the structure of another conventional evaporation filament.

FIG. 6 is a view showing the structure of another conventional evaporation filament.

FIG. 7 is a view showing the structure of another conventional evaporation filament.

[Explanation of symbols]

 1 core wire 2 auxiliary coil wire

Claims (2)

[Claims] 1. A vapor deposition filament using a refractory metal core wire, wherein a refractory metal auxiliary coil wire is spirally wound around the outer peripheral surface of the core wire. filament. 2. The filament for vapor deposition according to claim 1, wherein the auxiliary coil wire has a diameter of 0.1 mm to 1.5 mm.
The filament for vapor deposition is characterized in that the coil pitch of the auxiliary coil wire is 5 mm or less.