JPH04192521A - Plasma reactor - Google Patents

Abstract

PURPOSE:To achieve high heat efficiency by placing a pipe path which is cutoff from the internal space along one side of a cylindrical reaction container and inserting a pipe-shaped heater into this pipe path. CONSTITUTION:Along one side of a cylindrical reaction container 5, a pipe path 6 is added which is cutoff from the internal space and a pipe-shaped heater 7 is inserted into the pipe path 6 to form an internal heater. The pipe path 6 is normally made of quartz glass and the placement direction is parallel to the line of wafers A so that each wafer receives a uniform amount of heat when there are a plurality of wafers A in the reaction container 5. The pipe- shaped heater is not particularly limited in its shape and can be a standard type. In this way, a high heat efficiency is achieved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a plasma reactor. This invention relates to a plasma reactor that has been improved to achieve thermal efficiency.

[Conventional technology]

As is well known, plasma reactors are capable of performing plasma low-temperature etching processing, plasma low-temperature ashing processing, plasma C
This is a reactor used for VD, etc., and is mainly composed of a cylindrical reaction vessel equipped with a gas inlet pipe, a gas exhaust pipe connected to a vacuum system, and equipped with electrodes. Then, in a vacuum state, plasma is generated between the electrodes, thereby performing each of the above-mentioned processes.

The object to be processed, such as a wafer, is placed on a suitable support and housed in a cylindrical reaction vessel, and is subjected to a predetermined process using the plasma described above. Things need to be heated.

[Problem to be solved by the invention]

In conventional plasma reactors, heating of the object to be processed is performed by a heating means (photothermal heater such as infrared or far infrared or electric heater) installed outside the cylindrical reaction vessel. Externally installed heating means have the disadvantage of poor thermal efficiency.

The present invention was made in view of the above circumstances, and its purpose is to provide a plasma reactor that is improved so as to obtain high thermal efficiency.

[Means to solve the problem]

The above-mentioned object of the present invention is to provide a plasma reactor mainly composed of a cylindrical reaction vessel equipped with a gas inlet pipe and a gas exhaust pipe connected to a vacuum system, and in which an electrode is installed. This can be easily achieved by using a plasma reactor characterized in that a pipe line is provided in one direction, which is isolated from the internal space, and a rod-shaped heater is inserted into the pipe line.

[Effect]

The duct line in the cylindrical reaction vessel, which is isolated from its interior space in one direction, prevents the rod-shaped heater inserted therein from being exposed to the reaction gas under high vacuum.

The rod heater constitutes an internal heater to achieve high thermal efficiency.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, but the present invention is not limited to the following embodiments unless it exceeds the gist thereof.

Plasma reactors come in various types depending on their electrode structure, such as a cylindrical coaxial type, a counter electrode type, a capacitively coupled type, an inductively coupled type, and a parallel plate type. It mainly consists of a cylindrical reaction vessel equipped with a gas exhaust pipe connected to a vacuum system and an electrode. And the cylindrical reaction vessel is usually
Composed of quartz glass.

The plasma reactor of the present invention is characterized in that a duct line is provided in one direction inside the cylindrical reaction vessel and is isolated from the internal space of the cylindrical reaction vessel, and a rod-shaped heater is inserted into the cylindrical reaction vessel to constitute an internal heater.

Therefore, in the plasma reactor of the present invention, the electrode structure may be any of the above.

First, a cylindrical coaxial plasma reactor will be explained.

1 and 2 are explanatory diagrams schematically showing an example of a cylindrical coaxial plasma reactor configured vertically,
FIG. 1 is an explanatory overall cross-sectional view taken along the line XX in FIG. 2, and FIG. 2 is an explanatory cross-sectional view of important parts.

A cylindrical coaxial plasma reactor has a gas introduction pipe (1)
and a cylindrical reaction vessel (5) equipped with a gas exhaust pipe (2) connected to a vacuum system, an external electrode (3) closely disposed around the outer periphery of the reaction vessel, and a predetermined electrode inside the reaction vessel. It mainly consists of a cylindrical internal electrode (4) that is coaxially arranged at intervals and has a large number of small holes in the side wall, and the object to be treated is housed inside the cylindrical internal electrode (4) to generate plasma. It is processed.

In a cylindrical coaxial type plasma reactor, the plasma generation area is between the inner wall of the cylindrical reaction vessel (5) and the outer wall of the cylindrical internal electrode (4), and the plasma processing area is between the cylindrical internal electrode (4). It's inside.

An external electrode (4) is arranged in close contact around the cylindrical reaction vessel (5), and the external electrode is connected to a high frequency power source (10).

Inside the cylindrical reaction vessel (5), cylindrical internal electrodes (4) are coaxially arranged at predetermined intervals. The cylindrical internal electrode (4) is made of aluminum or alumite-treated metal, and has many small holes in its side wall. The diameter of the small hole is usually 0.5 to 1 Om
m, and are provided at intervals of 0.5 to 20 mm. The cylindrical internal electrode (4) is normally grounded as is.

In a cylindrical coaxial plasma reactor,
Since the cylindrical internal electrode (4) is grounded and maintained at ground potential, ions in the plasma are captured by the cylindrical internal electrode (4).

Therefore, in a cylindrical coaxial plasma reactor,
It is said that damage caused by charge-up due to plasma potential is relatively small.

The gas introduction pipe (1) is arranged externally to the cylindrical reaction vessel (5). The gas introduction pipe (1) is provided with a large number of gas ejection holes (not shown) in the longitudinal direction, and the plasma gas in the cylinder (20) is passed through the piping from the ejection holes into a cylindrical shape. introduced into the reaction vessel (5).

The gas exhaust pipe (2) is arranged externally to the cylindrical container (5). The gas exhaust pipe (2) is provided with a large number of gas suction holes (not shown) in the longitudinal direction, and the reaction exhaust gas inside the cylindrical reaction vessel (5) is driven by the vacuum system (30). , and is exhausted to the outside of the system from the suction hole via piping.

The object to be processed, such as a wafer (A), is supported by a wafer support made of, for example, several pillars (40) provided with notched grooves fixed with an appropriate number of rings (50), and a cylindrical internal electrode (4). is housed inside and subjected to plasma treatment. The above-mentioned wafer support is usually made of quartz, and is inserted into the cylindrical reaction vessel (5) from the lower part thereof by releasing the fixture (70) and lowering the pedestal (60). Ru.

The plasma reactor of the present invention is a cylindrical coaxial type plasma reactor as described above.
) is provided with a conduit (6) in one direction that is isolated from the internal space, and a rod-shaped heater (7) is inserted into the conduit to constitute an internal heater.

The conduit (6) is usually made of quartz glass, and its arrangement direction is such that when a plurality of wafers (A) are housed in the cylindrical reaction vessel (5), each wafer is heated uniformly. In order to achieve this, the direction is parallel to the direction in which Ueno 1-(A) is arranged.

The length of the pipe line (6) is determined by the length between the cylindrical reaction vessel (5) and the line, since uniform heating is achieved by heating the entire inside of the cylindrical reaction vessel (5). It is better to do so.

In the example shown in FIG. 2, the length of the pipe line (6) is made shorter than the length of the cylindrical reaction vessel (5), and by closing its tip, the inside of the cylindrical reaction vessel (5) is It is a structure that is separated from the space.

However, depending on the structure of the cylindrical reaction vessel (5), the length of the conduit (6) may be longer than that of the cylindrical reaction vessel (5) and may be passed through it. The tip of (6) does not need to be closed.

Of course, the contact area between the pipe line (6) and the cylindrical reaction vessel (5) is
It is a matter of course that the pipe line (6) of any of the above structures is sufficiently sealed and that the inside of the cylindrical reaction vessel (5) is maintained at a high vacuum.

The rod-shaped heater (7) inserted into the pipe (6) is not particularly limited, and any known heater can be used as is.

The cylindrical coaxial plasma reactor shown in FIGS. 1 and 2 differs from conventional cylindrical coaxial plasma reactors in that it has a plurality of cylindrical internal electrodes (4) inside a cylindrical reaction vessel (5). This is a cylindrical coaxial type plasma reactor improved by the present inventor, which has a multi-layered structure in which the small holes are arranged so that they do not substantially overlap.

In the example shown in FIGS. 1 and 2, two cylindrical internal electrodes (5) are arranged, but three or more can also be arranged.

The distance between the cylindrical internal electrodes (4) is not particularly limited, but is usually in the range of 5 to 50 mm.

In the above-mentioned improved cylindrical coaxial type plasma reactor, the conduit (6) is preferably disposed between the cylindrical internal electrodes, as shown in FIG.

As described above, when a plurality of wafers (A) are housed in the cylindrical reaction container (5), the wafers (
It is preferable to arrange them in the same direction parallel to the arrangement direction of A) (in a direction parallel to the cylindrical internal electrodes).

As described above, when the pipe (6) is arranged between the cylindrical internal electrodes, the pipe (6) is isolated from the plasma generation region and the plasma processing region, so the presence of the pipe (6) causes plasma Disturbances in generation and reaction are prevented.

Further, the radiant heat of the rod-shaped heater (7) inserted into the pipe (6) does not directly hit the wafer (A), so that more uniform heating of the entire wafer is achieved.

The above-mentioned improved cylindrical coaxial type plasma reactor in which the cylindrical internal electrodes (4) have a multilayer structure exhibits the following remarkable effects in addition to the above-mentioned effects, due to the characteristics of its electrode structure.

In other words, in a conventional cylindrical coaxial plasma reactor with a single internal electrode, plasma is generated between the internal electrode and the external electrode, so mainly due to electron collisions.
The temperature of the cylindrical reaction vessel (5) and the internal electrode rises with the processing time, and the temperature of the object to be processed also rises accordingly.

As a result, accurate temperature control of the object to be processed is difficult. On the other hand, in the cylindrical coaxial plasma reactor of the present invention, the internal electrodes have a multilayer structure, so that the second and subsequent internal electrodes are not heated by electron collisions, and therefore the internal electrodes are prevented from increasing in temperature. There is almost no accompanying temperature rise of the object to be processed.

As a result, the temperature of the object to be processed can be accurately controlled by the rod-shaped heater (7).

In addition, due to the multiple structure of the cylindrical internal electrodes, plasma ions collide with the walls of the cylindrical internal electrodes and are captured, thereby preventing them from flowing into the plasma processing region.

Further, since the cylindrical internal electrodes with the multilayer structure are arranged so that the small holes do not substantially overlap, ultraviolet rays emitted from the glow discharge region are effectively blocked.

Therefore, plasma damage to the object to be treated is further reduced compared to a conventional cylindrical coaxial type plasma reactor.

Although the cylindrical coaxial plasma reactor shown in FIGS. 1 and 2 is configured vertically, it can also be configured horizontally by using an appropriate wafer support.

Next, a counter electrode type plasma reactor will be explained.

FIG. 3 is an explanatory diagram schematically showing an example of a facing electrode type plasma reactor.

In the present invention, the opposed electrode type plasma reactor is
Basically, it can be configured exactly the same as the conventional one.

That is, in a facing electrode type plasma reactor, electrodes (3) and (4) together constitute external electrodes. The picture electrode is arranged in close contact with the outer periphery of the cylindrical reaction vessel (5).

Note that in FIG. 3, the gas introduction pipe and the gas exhaust pipe connected to the vacuum system are not shown.

Then, a pipe line (6) into which a rod-shaped heater (7) is inserted.
) As described above, when there are multiple wafers housed in the cylindrical reaction vessel (5), in order to achieve uniform heating for each wafer, as shown in FIG. Same direction parallel to the array direction (parallel to the wafer support)
It is best to place it in

A feature of the present invention is that the heater for heating the wafer is configured as an internal heater as described above. Therefore, the present invention can be applied to various plasma reactors other than those described above as long as it has such an internal heater. Also includes.

Further, the number of installed internal heaters can be increased to a plurality as required.

The plasma reactor of the present invention is operated and used in the same manner as a conventional plasma reactor.

The degree of vacuum in the cylindrical reaction vessel (5) is usually in the range of 0.1-10 Torr, and the plasma gas may be oxygen, nitrogen or nitrogen depending on the purpose of the treatment. , hydrogen, argon, ammonia, water, etc., and in the case of etching treatment, fluorine, oxygen, ozone, etc. are used.

〔Effect of the invention〕

According to the present invention described above, an improved plasma reactor is provided so that high thermal efficiency is achieved, and therefore, the industrial value of the present invention is significant.

[Brief Description of the Drawings] Figures 1 and 2 are explanatory diagrams schematically showing an example of a cylindrical coaxial plasma reactor configured vertically.
FIG. 1 is an explanatory overall cross-sectional view taken along the line XX in FIG. 2, and FIG. 2 is an explanatory cross-sectional view of important parts. FIG. 3 is an explanatory diagram schematically showing an example of a facing electrode type plasma reactor. In the figure, (1) is the gas inlet pipe, (2) is the gas discharge pipe, and (3) is the gas inlet pipe.
), (4) represents an electrode, (5) represents a cylindrical reaction vessel, (6) represents a pipe, and (7) represents a rod-shaped heater. Applicant Ramco Co., Ltd.

Claims (2)

[Claims] (1) In a plasma reactor mainly consisting of a cylindrical reaction vessel equipped with a gas inlet pipe and a gas exhaust pipe connected to a vacuum system, and in which an electrode is installed, a 1. A plasma reactor comprising a pipe line that is isolated from an internal space, and a rod-shaped heater inserted into the pipe line. (2) A cylindrical reaction vessel equipped with a gas inlet pipe and a gas exhaust pipe connected to a vacuum system, an external electrode closely disposed around the outer periphery of the reaction vessel, and a predetermined space between the external electrode and the external electrode arranged in close contact with the outer periphery of the reaction vessel. In a cylindrical coaxial type plasma reactor that is mainly composed of a cylindrical internal electrode that is arranged coaxially and has a large number of small holes in the side wall, a plurality of cylindrical internal electrodes are arranged in a cylindrical reaction vessel and each small hole is substantially The cylindrical internal electrodes are arranged so that they do not overlap, and a conduit is provided between the cylindrical internal electrodes in parallel with the cylindrical internal electrodes and is isolated from the internal space of the cylindrical reaction vessel. A plasma reactor characterized by inserting a rod-shaped heater into a plasma reactor.