JPH06101026A - Gas deposition device - Google Patents

Abstract

PURPOSE:To improve the density of the thick film or green compact deposited on a substrate and the adhesion with the substrate by uniformizing the size of the superfine particles evaporated from a evaporation source. CONSTITUTION:The crucible 3 housing the material to be evaporated 10 in the generation chamber of the superfine particles is disposed in a high-frequency current inductive coil 1. Right above an evaporation source A, the transporting pipe 8 which transports the superfine particles evaporated from the evaporation source A to a film forming chamber 10 is disposed so that a gas inlet 8a is opposite to the evaporating source A. The material to be evaporated 10 is heated in uniform temp. distribution by high-frequency current inductive heating, and evaporated as the superfine particles having uniform particle size, and transported to the film forming chamber 10 with carrier gas in the generation chamber of the superfine particles, and the film which has high density and storing adhesion is formed on the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas deposition apparatus for transporting ultrafine particles together with gas and injecting them at a high speed from a nozzle to form a thick film of ultrafine particles or a green compact on an opposing substrate.

[0002]

2. Description of the Related Art A conventional gas deposition apparatus is shown in its entirety in FIG. In this gas deposition apparatus, first, the evaporation material 14 in the evaporation source 20 is heated and evaporated in the atmosphere of the inert gas introduced by the needle valve 16 into the ultrafine particle generation chamber 18. The vapor that has become ultrafine particles by evaporation (in the form of aerosol) is evacuated by the vacuum pump 12 connected to the film forming chamber 22 via the valve 13, so that the film forming chamber 22
The inert gas as a carrier gas is sucked into the gas inlet 17a of the transfer pipe 17 by the pressure difference between the ultrafine particle generation chamber 18 and the ultrafine particle generation chamber 18, and is transferred to the film forming chamber 22 as indicated by an arrow a in the figure. As a result, the ultra-fine particles are ejected at high speed from the nozzle 19 attached to the tip of the carrier pipe 17 onto the substrate 11 directly below, forming a compact powder compact on the substrate 11, or by moving the substrate 11 to the arrow b. A thick film is formed by moving it as shown in FIG.

In such a gas deposition apparatus, an alumina-coated W basket as shown as the evaporation source 20, Ta boats, W boats, and B boats are also used.
N composite board or the like is used. Since the evaporation source 20 is connected to the AC power source 15 via the lead wire 21, heating of the evaporation material 14 in the evaporation source 20 is performed by energizing the evaporation material 14 to generate heat by the electric resistance. Resistance heating. Therefore, in such a heating method, first, the electrode portion such as the alumina-coated W basket as the evaporation source 20 generates heat, and this heat is generated by the evaporation material 1.
4 from the outside to the inside by evaporation material 14
Is heated.

[0004]

In the conventional gas deposition apparatus as described above, since the evaporation source is heated by resistance heating, the temperature distribution of the evaporated material which has become the molten metal becomes non-uniform. That is, since the electrode portion such as the basket has a high temperature, the evaporation material in the vicinity thereof has a high temperature, but inside the evaporation material distant from the electrode portion, it becomes low. Therefore, the diameter of the ultrafine particles evaporated from the surface of the evaporation material in the high temperature portion is larger than that from the surface of the evaporation material in the low temperature portion, and as a result, the diameters of the ultrafine particles conveyed to the film forming chamber are different, resulting in a particle size distribution. The full width at half maximum of becomes larger. In the gas deposition method, such nonuniformity of the diameter of the ultrafine particles causes a problem because the density of the film deposited on the substrate and the adhesion with the substrate are reduced.

The present invention has been made in view of the above problems, and by heating the substance to be vaporized so that its temperature distribution becomes uniform, the diameter of the ultrafine particles vaporized from the vaporization source is made uniform and the substrate is An object of the present invention is to provide a gas deposition apparatus capable of improving the density and adhesion of a deposited ultrafine particle film or green compact.

[0006]

The above object is to form a film of the evaporation source for storing the substance to be evaporated in the ultrafine particle generation chamber and the substance evaporated from the evaporation source by the carrier gas introduced into the ultrafine particle generation chamber. In a gas deposition apparatus provided with a transport pipe having a gas inlet for transporting into the formation chamber located in the ultrafine particle generation chamber, the vapor deposition source heating means uses high frequency induction heating. Achieved by the device.

[0007]

The substance to be evaporated is heated with a uniform temperature distribution by high frequency induction heating. As a result, the substance to be vaporized is evaporated from the evaporation source into ultrafine particles having a uniform diameter, which is sucked into the gas inlet of the transport pipe and transported to the film forming chamber. Therefore, a thick film or a green compact having high density and adhesion is formed on the substrate in the film forming chamber.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A gas deposition apparatus according to an embodiment of the present invention will be described below with reference to the drawings. The same components as those in the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a perspective view showing the details of the evaporation source A in the ultrafine particle generation chamber 18 (see FIG. 4) of the gas deposition apparatus of this embodiment. The structure other than the evaporation source A is shown. Although not provided, it is similar to the conventional example shown in FIG. In this embodiment, the evaporation material 10 has a cylindrical shape (outer diameter 21
mm Φ, inner diameter 15 mm Φ, height 15 mmH) crucible 3
The crucible 3 is housed in the high frequency induction coil 1 and placed on a cylindrical support base 4 made of alumina. The support base 4 is fixed to the water-cooled copper plate 6 fixed to the bottom wall portion of the ultrafine particle generation chamber 18 (FIG. 4) by the support portion 6a. The high frequency induction coil 1 and the crucible 3 are arranged concentrically with each other, and the inner diameter (40 mmΦ) of the high frequency induction coil 1 is sufficiently larger than the outer diameter of the crucible 3, so that they are not in contact with each other and are equally spaced all around. ing. Further, as is well known, the high frequency induction coil 1 is composed of a water cooling pipe and a conductive wire portion, and the water cooling pipe prevents heat generated by the conductive wire from being conducted to the crucible 3 or a space in the vicinity thereof. The conducting wire is connected to a high frequency power source (maximum output 5 kW, frequency 150 kHz) not shown. The evaporation source A is these crucible 3 and high frequency induction coil 1.
The conventional crucible 3 is heated by so-called high-frequency induction heating by the high-frequency induction coil 1.

Above the evaporation source A, a double pipe 7 for sucking vapor rising from the evaporation source A is arranged as shown in the figure. The double pipe 7 is composed of a small-diameter carrier pipe 8 and a large-diameter suction pipe 9, and the extra particle suction port 9a, which is a gap between the gas inlet 8a and the carrier pipe 8 and the suction pipe 9, is used as the evaporation source A. Is facing. The double pipe 7 is fixed to the side wall of the ultrafine particle generation chamber 18 like the transfer pipe 17 of FIG. 4, but unlike the conventional case, the suction pipe and the suction pipe 8 are provided outside the ultrafine particle generation chamber 18. The pipe 9 is branched, and only the transfer pipe 8 extends into the film forming chamber 10 like the transfer pipe 17 in FIG. 4, and the suction pipe 9 is connected to a vacuum pump (not shown).

A W-Re thermocouple 5 for measuring the temperature of the evaporation material 10 is attached to the bottom of the crucible 3 so as to penetrate the upper wall of the support 4, and the conductor 5 is as shown in FIG. Further, it passes through the notches of the support base 4 and the water-cooled copper plate 6, further extends to the outside of the ultrafine particle generation chamber 18, and is connected to a temperature controller (not shown). This temperature controller is also connected to the above-mentioned high frequency power source, and automatically controls the output of the high frequency power source according to the temperature measured by the thermocouple 5.

The gas deposition apparatus according to the embodiment of the present invention is constructed as described above, and its operation will be described below.

First, the gas inlet 8a of the double pipe 7 is connected to the evaporation source A.
Set in the flow path position of the ultrafine gas flow rising from
An inert gas (helium gas) is introduced into the ultrafine particle generation chamber 18 and at the same time, the film forming chamber 10 is evacuated to generate a predetermined differential pressure between the two chambers (2 atm for the ultrafine particle generating chamber 18 and 2 atm for the film forming chamber 10). 0.02 torr). Next, while the output is automatically controlled by the temperature controller (not shown) described above, a current is applied to the high frequency induction coil 1 from the above high frequency power source to penetrate the graphite crucible 3 and the evaporation material 10 in the crucible 3 and to pass the time. Crucible 3 by electromagnetic induction given a changing magnetic field
An eddy current is generated in the crucible evaporation material 10. Therefore, the evaporation material 10 generates heat from the inside due to the eddy current loss, and the temperature rises and melts with a uniform temperature distribution. In this heating process, since the high frequency induction coil 1 is cooled by the water cooling pipe as described above, there is no heat conduction from the outside of the evaporation source A. The vapor of Au, which has become ultrafine particles, rises from the evaporation material 10 that has become a molten metal, and thereafter this evaporation temperature is maintained at a predetermined temperature by the above-mentioned temperature controller (not shown).
Further, since the eddy current generated in the evaporation material 10 flows in the magnetic field generated by the high frequency induction coil 1 described above, the evaporation material 10 itself is agitated by the interaction with the magnetic flux due to the eddy current. As a result, the temperature distribution of the evaporation material 10 becomes more uniform, and a gas of ultrafine particles having a uniform particle diameter rises from the evaporation source A. The ultrafine particle gas having a uniform particle diameter is used for the ultrafine particle generating chamber 18 and the film forming chamber 1
The carrier pipe 8 is entrained in the inert gas by the pressure difference between 0 and
Is sucked into the gas inlet 8a and is conveyed to the film forming chamber 10. The extra particles existing on the outer periphery of the gas flow of the ultrafine particles rising from the evaporation source A are sucked into the extra particle suction pipe 9a, and the generation of aggregates in the ultrafine particle generation chamber 18 is prevented.

The ultrafine particles transferred to the film forming chamber 10 are transferred to the substrate 1 by the nozzle 19 (inner diameter 0.1 mm) as in the conventional case.
Although it is sprayed on 1, a thick film or green compact is formed, but the particle size of these ultrafine particles is different from conventional ones,
That is, since the half-width of the particle size distribution is small, the density is high and the adhesion is strong.

FIG. 2 shows a Ni substrate (200) which moves at 7.5 mm / min, using Au as the evaporation material 10 under the above-mentioned apparatus and setting conditions, the melt temperature being 1440 ° C.
It is a SEM photograph of an Au film when an Au film is formed on (heated to ° C). That is, A of FIG. 2 is a SEM photograph in which the Au film is magnified 50 times, B is 400 times, and C is 50,000.
It is a double SEM photograph. The ultrafine particles deposited in A and B of FIG. 2 are in the form of small particles when the movement of the Ni substrate is stopped for a predetermined time. For comparison, as shown in FIG. 4, an alumina-coated W basket is used as an evaporation source, and Au is evaporated by resistance heating to form an Au film, and an SEM photograph is shown in FIG. A is 400 times, B is 5
It is an enlargement of 0000 times. However, in this case, Au
Other setting conditions such as the molten metal temperature are the same as those in the case of high frequency induction heating in FIG. From the comparison with FIGS. 2 and 3 (particularly, comparison between C of FIG. 2 and B of FIG. 3), it is apparent that the film formed by high frequency induction heating has a particle diameter smaller than that of the film formed by conventional resistance heating. It can be seen that it is uniform. That is, in FIG. 3, the deposited particle size of the substrate is from 10 nm to 100 nm.
It can be seen from FIG. 2 that such aggregates are not observed although there are variations of about 1 nm and aggregates of about 1 μm.

Next, the results of measuring the adhesion of the Au film as shown in FIG. 2 are shown in Table 1 below. The measured values and shear strengths shown in Table 1 are the results obtained by forming films on seven substrates heated to 200 ° C., peeling the films off from each of the substrates, and measuring all of them, and all the films were broken in the Au film.

[0017]

[Table 1]

From the above measurement results, the shear strength of the film formed by the gas deposition apparatus according to this embodiment is 2
It is 0 ± 5 kgf, which is much larger than the conventional 10 ± 5 kgf.

Although the embodiments of the present invention have been described above, needless to say, the present invention is not limited to these, and various modifications can be made based on the technical idea of the present invention.

For example, in the above embodiments, the high frequency induction coil 1 was used as the heating source of the evaporation source A, but if it can heat the evaporation material 10 with a uniform temperature distribution, for example, a flat plate shape. Induction coil wound on a crucible 3
Other high-frequency induction heating sources may be used, such as facing each other and heating by electromagnetic induction thereby.

Further, although Au which is a conductor is used as the substance to be vaporized in the above embodiments, other conductor substances may be used, and further an insulating substance may be used. However, in this case, the insulating material generates heat due to dielectric loss and also evaporates with a uniform temperature distribution.

[0022]

As described above, according to the present invention, the diameters of the ultrafine particles evaporated from the evaporation source are made uniform, the thick film of the ultrafine particles or the density of the green compact deposited on the substrate, and the adhesion force with the substrate. Can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing details of an evaporation source of a gas deposition apparatus according to an embodiment of the present invention.

2A, 2B and 2C are SEM photographs at various magnifications showing the structure of a film formed by the same apparatus.

3A and 3B are SEM photographs at various magnifications showing the structure of a film formed by resistance heating.

FIG. 4 is a schematic view showing an entire gas deposition apparatus according to a conventional example.

[Explanation of symbols]

 1 high-frequency induction coil 3 crucible 8 carrier pipe 8a gas inlet 10 evaporation material 18 ultrafine particle generation chamber 22 film formation chamber A evaporation source

Claims (1)

[Claims] 1. An evaporation source for storing a substance to be evaporated in an ultrafine particle generation chamber, and a gas inlet for conveying a substance evaporated from the evaporation source into a film forming chamber by a carrier gas introduced into the ultrafine particle generation chamber. In the gas deposition apparatus, which comprises a transfer pipe located in the ultrafine particle generation chamber, the heating means of the evaporation source is high-frequency induction heating.