JP4585288B2 - Solid raw material vaporizer and solid raw material vaporization method - Google Patents

Description

  The present invention relates to a solid raw material vaporizer and a solid raw material vaporization method, and more particularly to a solid raw material vaporizer and a solid raw material vaporization method in which a heater is provided in a raw material container apart from a solid raw material.

In recent years, it is often required to deposit thin films (several nm to several μm) of various materials such as W, Al, Cu, Ta, TaN, TiN, SiO ₂ , SiOC, and SiN with good coverage. For example, in recent years, Cu (copper) wiring is being adopted for semiconductor devices. In forming Cu wiring, deterioration of element characteristics due to diffusion of Cu into Si (silicon), deterioration of workability due to poor adhesion to the insulating film, oxidation inside without forming a passive oxide film It is necessary to solve problems such as deterioration of wiring characteristics due to progressing to the above. The barrier metal is provided at the interface between Cu and the wiring interlayer film as one means for solving these problems. As the barrier metal, a single layer film or a multilayer film of Ta (tantalum) or TaN (tantalum nitride) is used, and a sputtering method is conventionally used as the film formation method.

  The barrier metal is indispensable for forming the Cu wiring as described above, and there is a minimum film thickness required for solving the above-described problems. On the other hand, a barrier metal with a high specific resistance increases the resistance of the Cu wiring, so it is necessary to make the thickness of the barrier metal as thin as possible from the viewpoint of speeding up the device, and it is uniformly deposited on the pattern with the minimum film thickness It is desirable to do.

  A chemical vapor deposition (CVD) method is known as a method suitable for such a requirement. In the chemical vapor deposition method, when a solid material having a low vapor pressure is used, it is common to increase the vapor pressure by heating in order to ensure a sufficient amount for film growth.

  In the conventional solid raw material vaporizer, the solid raw material in the container is heated and vaporized by providing a heater outside the raw material container. The present inventor conducted an experiment on the course of consumption of a solid material in a conventional solid material vaporizer.

  Fig.5 (a) is a schematic diagram which illustrates the middle course in which the solid raw material with a low vapor pressure is consumed in the conventional solid raw material vaporizer. As shown in the figure, a conventional solid raw material vaporizer 1000 includes a raw material container 110 for storing a solid raw material 100, a heater 200 provided outside the raw material container 110, and a pipe for supplying gas into the raw material container 110. 120 and a pipe 130 for supplying vaporized gas generated in the raw material container 110 to a heat treatment apparatus (not shown). According to this conventional solid material vaporizer 1000, it was found that the solid material 100 having a low vapor pressure is preferentially consumed from the vicinity of the side wall of the material container 110. That is, it has been found that a temperature gradient occurs between the portion of the solid material 100 in the vicinity of the heater 200 and the center portion of the solid material 100 in terms of heat conduction. In the case of a solid raw material having a low vapor pressure, the raw material partial pressure in the container is originally low, so that it is not easily affected by the lowering of the raw material partial pressure caused by the carrier gas.

  As a result, when the solid raw material 100 is further consumed and does not come into contact with the raw material container 110, the solid raw material 100 becomes difficult to be heated and is not vaporized, and there is a problem that generation of vaporized gas becomes unstable.

  FIG. 5B is a schematic view illustrating the course of the consumption of the solid material having a high vapor pressure in the conventional solid material vaporizer. As shown in the figure, it was found that the solid raw material 100 having a high vapor pressure is preferentially consumed in the portion where the carrier gas hits. That is, it was found that the solid raw material 100 having a high vapor pressure is vaporized even at a relatively low temperature, and thus is not significantly affected by the temperature gradient in the solid raw material 100 and depends on the partial pressure of the solid raw material. Therefore, it is preferentially consumed from the portion where the raw material partial pressure is lowered by the carrier gas.

  Thus, the conventional solid material vaporizer 1000 has a problem that generation of vaporized gas becomes unstable particularly in a solid material having a low vapor pressure.

Moreover, in order to solve such a problem, a solid material vaporization apparatus in which a heating unit and a heat conduction member are provided in a solid material has also been proposed (see, for example, Patent Document 1). In this proposal, the entire region of the solid material is uniformly heated by the effect of heat conduction.
JP 2002-359238 A

  However, in the solid raw material vaporizer in which the heating unit and the heat conducting member are provided in the solid raw material, the entire area of the solid raw material is always kept at a high temperature, so that a very large heat source is required and the efficiency is low.

  Further, if the solid raw material is heated too much, problems such as decomposition of the solid raw material occur, so there is an upper limit on the heating temperature, and there is a problem that the solid raw material cannot be supplied sufficiently.

  The present invention has been made on the basis of recognition of such problems, and an object of the present invention is to provide a solid raw material vaporization apparatus and a solid raw material vaporization method that can efficiently and stably supply vaporized gas in a solid raw material having a low vapor pressure. It is something to try.

In order to achieve the above object, according to one aspect of the present invention,
A raw material container for containing a solid raw material;
Piping for introducing gas into the raw material container;
Piping for discharging gas out of the raw material container;
A heater provided on the upper part in the raw material container, which can be set apart from the solid raw material accommodated in the raw material container, and a heater,
There is provided a solid raw material vaporizer characterized by comprising:

Here, the heater may be movable in the vertical direction.
The heater may have a plurality of through holes.
In addition, the lower surface of the heater may be a downwardly convex curved surface.

  According to another aspect of the present invention, the solid material stored in the raw material container is heated and vaporized by a heater provided in the raw material container so as to be separated from the solid raw material. A featured solid raw material vaporization method is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the solid raw material vaporization apparatus and solid raw material vaporization method which can vaporize the solid raw material with a low vapor pressure efficiently, and can supply vaporization gas stably can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view illustrating a cross-sectional structure of a solid material vaporizer according to an embodiment of the present invention.
As shown in the figure, a solid raw material vaporizer 1 according to an embodiment of the present invention includes a raw material container 11 for storing a solid raw material 10, an inlet 12 for a carrier gas supplied into the raw material container 11, and a vaporized gas. The outlet 13 is provided. Further, a disk-shaped heater 14 is provided near the center in the raw material container 11. The heater 14 is supported by a columnar support portion 15 installed in the upper center of the raw material container 11.

FIG. 2 is a schematic view illustrating the planar structure of the main part of the solid raw material vaporizer according to the embodiment of the invention.
That is, FIG. 2 is a schematic view illustrating the planar structure of the heater 14. As shown in the figure, a large number of small holes (heater heater openings 16) are provided on the bottom surface of the disk-shaped heater 14. The carrier gas introduced into the container is supplied to the surface of the solid raw material 10 through these heater openings 16 as appropriate.

  The heater 14 is provided on the solid raw material 10 away from the solid raw material 10. Further, since the bottom area of the heater 14 is smaller than the bottom area of the raw material container 11, it does not contact the side surface of the raw material container 11. Therefore, most of the heat of the heater 14 is not transmitted to the side surfaces of the solid raw material 10 and the raw material container 11 by heat conduction by contact.

  In the solid raw material vaporizer according to the embodiment of the present invention, the heater 14, the raw material container 11, and the support 15 are heated by separate heaters to vaporize the solid raw material 10. For example, when the solid raw material is PDMAT (Pentakis Dimethyl Amino Tantalum) used as a raw material of tantalum (Ta), the heater 14 is heated to 70 to 130 degrees Celsius, and the raw material container 11 and the support portion 15 are 20 degrees Celsius. Heat to 80-80 degrees. Examples of the heating method include a method of energizing an electric heater accommodated in the heater 14.

  The solid raw material 10 is vaporized by heating and reacted with the carrier gas supplied from the inlet 12 of the carrier gas. The vaporized gas is supplied from a vaporized gas outlet 13 into a heat treatment apparatus (not shown).

  Since the heater 14 is provided apart from the solid material 10, the heat of the heater 14 is transmitted to the upper surface side of the solid material 10 by radiation. It is also transmitted by heat conduction through the carrier gas. Therefore, the upper surface of the solid raw material 10 becomes high temperature, and the vapor pressure in the space above the upper surface increases. That is, the solid raw material 10 is vaporized in order from the upper surface. When the uppermost surface of the solid raw material 10 is vaporized, a sublimation reaction in which the lower surface is exposed and the exposed new surface is heated and vaporized is continuously repeated. The solid raw material 10 is continuously consumed from the upper layer toward the lower layer. Therefore, vaporized gas is generated stably. The vaporized solid raw material is carried out from the outlet 13 on the carrier gas.

  Therefore, according to the embodiment of the present invention, the solid raw material 10 can be continuously and efficiently consumed from the upper surface side to the lower surface.

  In the solid raw material vaporizer according to the embodiment of the present invention, the heater 14 is provided at the center of the raw material container 11, so that the center of the upper surface of the solid raw material 10 has the highest temperature. That is, since the heater 14 is heated to a higher temperature than the raw material container 11, the influence of the vicinity of the side wall of the raw material container 11 in the solid raw material 10 due to the heating of the raw material container 11 can be eliminated.

  Further, the heater 14 does not always need to heat the entire area of the solid raw material 10, and at least the vicinity of the center of the uppermost surface of the solid raw material 10 may be heated. Therefore, the heat source of the heater 14 may be smaller than conventional solid material vaporizers.

  Furthermore, as illustrated by the arrows in FIG. 1, the heater 14 may be movable in the vertical direction. If it does in this way, the distance of the uppermost surface of the solid raw material 10 which becomes low as it is consumed, and the heater 14 can always be kept constant, and the solid raw material 10 can always be heated at a fixed temperature.

  Furthermore, by providing the heater 14 in the space in the container, the temperature of the wall surface in contact with the space in the container can be raised, and reattachment of the evaporated solid raw material 10 can be prevented.

  Thus, according to the solid raw material vaporizer according to the embodiment of the present invention, by providing the heater 14 in the raw material container 11 apart from the solid raw material 10, the solid raw material 10 is continuously and efficiently formed from the upper surface side. Can be vaporized. As a result, the vaporized gas can be stably supplied into the heat treatment apparatus, and a uniform thin film can be deposited on the semiconductor substrate or the like with good coverage.

  As a result, for example, element characteristics are deteriorated due to diffusion of Cu into Si, workability is deteriorated due to poor adhesion to the insulating film, and oxidation proceeds to the inside without forming a passive oxide film. A highly reliable barrier metal capable of preventing the deterioration of wiring characteristics due to the above can be formed with a uniform film thickness.

Next, a modified example of the present embodiment will be described.
FIG. 3 is a schematic view illustrating the cross-sectional structure of a solid material vaporizer according to a modification of the present embodiment.
The heater 14 in this modification has a downwardly convex hemispherical shape. Also in the heater 14 in this modification, a large number of small holes (heater heater openings 16) are provided, and the carrier gas is appropriately heated through these heater heater openings 16 to promote heat conduction. .

  Since the heater 14 in this modification is hemispherical, the distance between the heater 14 and the solid material 10 is the smallest at the center of the upper surface of the solid material 10. That is, the center of the surface of the solid raw material 10 is closest to the heater 14. As a result, the center of the upper surface of the solid material 10 can be set to the highest temperature, and the influence of the vicinity of the side wall of the material container 11 in the solid material 10 being heated by the heating of the material container 11 can be reduced.

  According to this modification, by providing the downwardly convex hemispherical heater 14 in the raw material container 11, the solid raw material 10 can be continuously and efficiently vaporized from the center of the upper surface. Also in this modified example, the same effect as that obtained in the above-described embodiment can be obtained.

  Further, even if the heater 14 is formed of a metal wire such as a filament and is deformed downwardly, the same effect as in this embodiment can be obtained.

Next, a second variation of this embodiment will be described.
FIG. 4 is a schematic view illustrating the cross-sectional structure of the solid material vaporizer according to this modification.
In this modification, the position of either the carrier gas inlet 12 or the vaporized gas outlet 13 is changed.

  FIG. 4A shows an example in which the position of the inlet 12 for the carrier gas is changed. In this specific example, as shown in the figure, the carrier gas passes through the support portion 15 and is supplied into the container from the center of the heater 14. That is, the support portion 15 not only serves to hold the heater 14 but also serves as an inlet for the carrier gas. The vaporized gas outlet 13 is provided at the same position as in the above-described embodiment.

  In this way, by supplying the carrier gas from the center of the heater 14, the heated carrier gas is supplied to the center of the upper surface of the solid material 10, so that the center of the upper surface of the solid material 10 has the highest temperature. Therefore, the influence of the vicinity of the side wall of the raw material container 11 in the solid raw material 10 being heated by the heating of the raw material container 11 can be reduced.

Therefore, also in this specific example, as illustrated in FIG. 3, the solid raw material 10 can be continuously and efficiently vaporized from the center of the upper surface by providing the hemispherical heater 14 in the raw material container 11. .
Also in this specific example, the same effect as that obtained in the above-described embodiment can be obtained.

On the other hand, FIG. 4B shows a specific example in which the position of the vaporized gas outlet 13 is changed.
That is, the structure is such that the vaporized gas is discharged from the center of the heater 14 through the support portion 15 without changing the position of the inlet 12 of the carrier gas. Even in this case, since the center of the upper surface of the solid raw material 10 becomes a part of the gas passage, it is heated to a high temperature, and the above-described effects can be obtained.

The embodiments of the present invention have been described above with reference to specific examples.
However, the present invention is not limited to these specific examples. For example, specific structures, materials, types of feedstocks, and the like of the solid raw material vaporizer according to the present invention are appropriately selected from those known by those skilled in the art within the scope of the present invention.

It is a schematic diagram which illustrates the cross-sectional structure of the solid raw material vaporization apparatus concerning embodiment of this invention. It is a schematic diagram which illustrates the planar structure of the principal part of the solid raw material vaporization apparatus concerning embodiment of this invention. It is a schematic diagram which illustrates the cross-sectional structure of the solid raw material vaporization apparatus concerning the 1st Example of this invention. It is a schematic diagram which illustrates the cross-section of the solid raw material vaporization apparatus concerning the 2nd Example of this invention. In the conventional solid raw material vaporizer, it is a schematic diagram which illustrates the middle course in which a solid raw material is consumed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid raw material vaporizer 10 Solid raw material 11 Raw material container 12 Carrying gas inlet 13 Evaporated gas outlet 14 Heating heater 15 Support part 16 Heating heater opening part 100 Solid raw material 110 Raw material container 120 Gas inlet 130 Gas outlet 200 Heater 1000 Solid Raw material vaporizer

Claims (5)

A raw material container for containing a solid raw material;
Piping for introducing gas into the raw material container;
Piping for discharging gas out of the raw material container;
A heater provided on the upper part in the raw material container, which can be set apart from the solid raw material accommodated in the raw material container, and a heater,
A solid material vaporizer characterized by comprising:   2. The solid material vaporizer according to claim 1, wherein the heater is movable in a vertical direction.   The solid material vaporizer according to claim 1, wherein the heater has a plurality of through holes.   The solid raw material vaporizer according to any one of claims 1 to 3, wherein a lower surface of the heater is a curved surface convex downward. A solid raw material vaporization method comprising heating a solid raw material stored in a raw material container by a heater provided inside the raw material container so as to be spaced apart from the solid raw material.

Images