JPH07169706A - Vertical heat-treating device and vacuum treating device - Google Patents

Abstract

PURPOSE:To prevent the scattering of particles generated by a rotating mechanism in the reaction tube of a vertical heat-treating device which performs heat treatment on an object to be treated while the holder of the object to be treated is rotated in the reaction tube by means of the rotating mechanism. CONSTITUTION:A rotating mechanism 3 which is rotated by utilizing magnetic coupling is provided in a cap section 22 which airtightly seals a reaction tube 1 when a wafer boat 14 is carried in the tube 1 and an inert gas supply tube 61 and inert gas exhaust tube 62 are provided so that the tubes 61 and 62 can be opened in the bearing space of the mechanism 3. In addition, the outer end side of the tube 62 is connected to a vacuum pump 51. While particles from a ceramic bearing, etc., stay in the bearing space S, scattering of the particles into the tube 1 can be prevented, because the space S is evacuated to a vacuum before the tube 1 is evacuated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical heat treatment apparatus and a vacuum treatment apparatus.

[0002]

2. Description of the Related Art A vertical heat treatment apparatus is generally known as an apparatus for performing heat treatment such as CVD, oxidation or thermal diffusion on a semiconductor wafer. In this device, semiconductor wafers are vertically arranged in a shelf shape on a wafer boat, which is a holder, and held, and are introduced into an upright reaction tube from its lower end opening to seal the opening and perform a predetermined heat treatment. However, the wafer boat may be rotated around the vertical axis in order to make the process uniform.

FIG. 4 is a view showing a conventional vertical heat treatment apparatus for performing oxidation / diffusion. The reaction tube 1 has a double tube structure composed of an inner tube 1a and an outer tube 1b made of, for example, quartz. A large number of gas introduction holes 1 are formed in the ceiling of the inner pipe 1a.
c is formed. A heater 11 is arranged outside the reaction tube 1 so as to surround it, and a boat elevator 2 that is moved up and down by, for example, a ball screw is installed below the reaction tube 1. This boat elevator 2 is provided with a cap portion 22 for sealing the lower end opening of the reaction tube 1 via an O-ring 21, and a rotating shaft 31 extending vertically is rotated at the center of the cap portion 22. A rotating mechanism 3 is attached. A heat retaining cylinder 13 is placed on the upper end of the rotary shaft 31 via a rotary table 12, and a wafer boat 14 which is a holder for vertically arranging and holding wafers in a shelf shape is placed on the heat retaining cylinder 13. There is. A gas supply pipe 15 and an exhaust pipe 4 are connected to the reaction pipe 1.

The rotating mechanism 3 is provided with a pulley 32 rotatable about a vertical axis. When the pulley 32 is rotated by the motor M via the belt 23, the rotating shaft 31 is rotated by magnetic coupling. Has been done. Therefore, when the motor M is driven, the rotation shaft 31 rotates and the wafer boat 14 rotates.

[0005]

Since the rotating mechanism 3 uses the magnetic coupling to transmit the rotating force, the rotating shaft 3
The bearing space of No. 1 is sealed from the outside, but in the bearing space,
A ceramic bearing having an inner ring and an outer ring made of stainless steel and a ceramic rolling element is used so that a lubricating oil that becomes a contamination source of a wafer is not used. However, particles are slightly generated from this ceramic bearing.

A magnet made of a rare earth element having excellent heat resistance and strong magnetic force, which is used for magnetic coupling, is coated because it has brittle characteristics. However, the coating peels off by some kind of impact to generate particles. When the material is exposed, it is corroded by the corrosive process gas that enters the bearing space, and more and more particles are generated.

Here, after the wafer boat 14 is loaded into the reaction tube 1, the inside of the reaction tube 1 is evacuated by the exhaust pipe 4.
At this time, there is a problem that particles accumulated in the rotating mechanism 3 scatter in the reaction tube 1 and contaminate the wafer W.

The present invention has been made under these circumstances, and an object thereof is to provide a vertical heat treatment apparatus capable of preventing particles generated from a rotating mechanism from scattering in a reaction tube. To do.

Another object of the present invention is that in a vacuum processing apparatus having a vacuum chamber in which a drive transmission shaft is arranged and an object to be processed is placed, particles generated from the drive transmission shaft are scattered in a reaction tube. It is to provide a vacuum processing device that can prevent the above.

[0010]

According to a first aspect of the present invention, a holder for an object to be processed is supported by a rotating mechanism via a rotating shaft,
In a vertical heat treatment apparatus for performing heat treatment on an object to be processed while rotating a holder in a reaction tube, in order to evacuate a bearing space in a rotation mechanism communicating with the reaction tube,
Vacuum evacuation means having an exhaust port opened in the bearing space,
Before evacuating the inside of the reaction tube, a control unit that controls the bearing space to be evacuated by the evacuation means,
It is characterized by having.

According to a second aspect of the present invention, in the first aspect of the present invention, the rotating mechanism magnetically couples the driven-side magnet provided on the rotating shaft to the driven-side magnet outside the bearing space. It is characterized in that it is provided with a drive side magnet to be rotated.

According to a third aspect of the present invention, there is provided a vacuum processing apparatus in which a transfer means is provided in a vacuum chamber in which an object to be processed is placed,
A cover for covering the drive transmission portion of the transfer means, a vacuum exhaust means for vacuum exhausting the space inside the cover, and a vacuum exhaust means for exhausting the space inside the cover before exhausting the vacuum chamber. And a control unit for controlling the above.

[0013]

[Function] A large number of objects to be processed are mounted on the holder and loaded into the reaction tube. After that, the inside of the reaction tube is evacuated, but before that, the bearing space in the rotating mechanism, for example, the rotating mechanism utilizing magnetic coupling is evacuated. Particles generated from the bearings, magnets, etc. are accumulated in the bearing space, but the particles are discharged to the outside by first evacuating the bearing space. Therefore, when the inside of the reaction tube is evacuated, scattering of particles from the bearing space can be suppressed, and contamination of the object to be processed can be prevented.

In the vacuum apparatus according to the third aspect of the present invention, the particles generated from the drive transmission portion of the transfer means are retained in the cover, the inside of the cover is evacuated to discharge the particles, and then the vacuum chamber is evacuated. Since the gas is exhausted, scattering of particles into the vacuum chamber can be suppressed.

[0015]

1 and 2 are views showing an embodiment of the present invention and its main portion, respectively, and the same portions as those in FIG. 4 are designated by the same reference numerals. The reaction tube 1 is configured as a double tube structure composed of an inner tube 1a and an outer tube 1b made of, for example, quartz, and the inner tube 1a
A large number of gas introduction holes 1c are formed in the ceiling portion of the.
A heater 11 is arranged outside the reaction tube 1 so as to surround it, and below the reaction tube 1, a boat elevator 2 is installed which is moved up and down by, for example, a ball screw.

The boat elevator 2 is provided with a cap portion 22 for sealing the lower end opening of the reaction tube 1 through an O-ring 21, and a rotary shaft extending vertically is provided at the center of the cap portion 22. A rotation mechanism 3 for rotating 31 is attached. A heat retaining cylinder 13 is placed on the upper end of the rotary shaft 31 via a rotary table 12, and a wafer boat 14 which is a holder for vertically arranging and holding the wafers in a shelf shape is placed on the heat retaining cylinder 13. There is.

The reaction tube 1 includes an inner tube 1a and an outer tube 1b.
One end of a gas supply pipe 15 for supplying a processing gas is connected therebetween, and the other end side of the gas supply pipe 15 is connected to a gas supply source (not shown) via a valve V1.
Further, one end of an exhaust pipe 4 for exhausting from the inside of the inner pipe 1a is connected to the reaction pipe 1, and the other end side of the exhaust pipe 4 is connected to a vacuum pump 51 via a main valve V2. There is. The exhaust pipe 4 is provided with a sub-valve V3 in parallel with the main valve V2 in order to avoid rapid exhaust at the initial stage of vacuum exhaust.

The rotating mechanism 3 has a rotating shaft 31 rotatable about a vertical axis, while the wafer boat 14 is provided with a motor M, and a belt 23 is provided between the pulley 32 and the motor M. ing. The structure of the rotating mechanism 3 will be briefly described with reference to FIG.
The inner casing 51 fixed to the cap portion 22 is rotatably supported via ceramic bearings 5A and 5B, and the ceramic bearing 5 is provided outside the inner casing 51.
The outer casing 52 is rotatably supported via C and 5D. A driven side permanent magnet 53 and a drive side permanent magnet 54 are provided between the rotating shaft 31, and the inner casing 51 and the outer casing 52, respectively. Therefore, when the pulley 32 provided at the lower end of the outer casing 52 rotates. The rotating shaft 31 rotates due to the magnetic coupling.

A bearing space S communicating with the inside of the reaction tube 1 is formed between the rotary shaft 31 and the inner casing 51, and the inner casing 51 has, for example, an upper region of the bearing space S. An inert gas supply pipe 61 and an inert gas exhaust pipe 62 are connected so as to open respectively. A valve V4 is provided in the inert gas supply pipe 61, while the inert gas exhaust pipe 62 is connected to the vacuum pump 51 side of the valve V2 in the exhaust pipe 5 via the valve V5.
In this embodiment, the inert gas exhaust pipe 62 and the vacuum pump 51 constitute vacuum exhaust means.

In this example, a cover 55 is provided on the rotary shaft 31 to cover the permanent magnet 54 so that particles generated from the driven permanent magnet 54 do not scatter in the bearing space S. However, in the present invention, the cover 55 may be omitted. Further, inside the rotary shaft 31, a communication pipe 56 that communicates an upper region and a lower region of the bearing space S is formed so that exhaust can be exhausted to every corner of the bearing space S. A water cooling mechanism may be incorporated in the rotating mechanism 3 for cooling.

The vertical heat treatment apparatus is provided with a control unit 10 for controlling the opening / closing sequence of each of the valves V1 to V5 described above.

Next, the operation of the above embodiment will be described. First, a wafer boat 14 on which a large number of wafers W to be processed are mounted is lifted by the boat elevator 2 and loaded into the reaction tube 1, and the cap portion 21 hermetically seals the lower end opening of the reaction tube 1. . The inside of the reaction tube 1 is previously heated to, for example, about 600 ° C. by the heater 11, and after the wafer boat 14 is loaded, the temperature is raised to a heat treatment temperature of, for example, 900 to 1200 ° C.

On the other hand, an inert gas such as nitrogen gas is supplied to the reaction tube 1 from a gas supply pipe (not shown), and after the wafer boat 14 is loaded into the reaction tube 1, the controller 10 is operated.
Then, the supply of nitrogen gas is stopped based on a predetermined sequence program, the valve V5 is subsequently opened, and the rotating mechanism 3 is driven by the vacuum pump 51 through the inert gas exhaust pipe 62.
The bearing space S therein is evacuated for 10 seconds, for example.

Next, the valve V5 is closed, and the sub valve V3
And the inside of the reaction tube 1 is evacuated for 30 seconds, and then the main valve V2 is opened. Then, after the pressure in the reaction tube 1 reaches, for example, 1 × 10 ⁻³ Torr, the valve V2 is closed,
The valve V1 is opened to introduce a processing gas required for oxidation or thermal diffusion into the reaction tube 1 through the gas supply pipe 15, and the inside of the reaction pipe 1 is maintained at normal pressure through an exhaust pipe 4 by an exhaust pump (not shown). A predetermined heat treatment is performed on the wafer W.

Further, for example, the valve V1 and the valve V5 are opened at the same time when the valve V1 is opened, and nitrogen gas is supplied to the bearing space S of the rotating mechanism 3 from the inert gas supply pipe 61 at a flow rate of 0.5 liters per minute. However, the inside of the bearing space S is exhausted through the inert gas exhaust pipe 62, and thus the processing gas in the reaction tube 1 is prevented from entering the bearing space S and corrosion of the bearing and the like is prevented. Then, the pulley 32 of the rotating mechanism 3 is rotated by the motor M via the belt 23, and as described above, the rotating shaft 31 is rotated by the magnetic coupling and the wafer boat 14 is rotated.

By rotating the rotating shaft 31, particles are generated from the ceramic bearings of the rotating mechanism 3 and nitrogen gas is flowing in the bearing space S, so that some of the particles are discharged to the outside, but the remaining particles. Are adhered and retained on the ceramic bearings 5A, 5B and corners. Therefore, if the bearing space S is first evacuated after loading the wafer W into the reaction tube 1 as in the above-described embodiment, the particles in the bearing space S are discharged to the outside. Therefore, even if the inside of the reaction tube 1 is evacuated, no particles are scattered from the bearing space S into the reaction tube 1 at all, or the wafer W is prevented from being contaminated. When the cover 55 is not used in the rotating mechanism 3, the driven permanent magnet 54 also becomes a source of generation of particles, and in this case, the particles from here are similarly exhausted to the outside beforehand through the inert gas exhaust pipe 62.

In the above, the inert gas supplied to the bearing space S may be argon gas, neon gas or the like in addition to nitrogen gas. The vacuum pump for evacuating the bearing space S may be different from the vacuum pump for evacuating the reaction tube 1, or when the reaction tube 1 is evacuated. The bearing space S may be evacuated. Further, the vertical heat treatment apparatus of the present invention is not limited to the oxidation and diffusion treatment, and may be one that performs CVD, etching, ashing, or the like.

Another invention will now be described with reference to FIG. 3. FIG. 3 shows a vacuum load lock chamber 71 which is a part of a vacuum processing apparatus for performing vacuum processing such as etching, CVD or ion implantation. The load lock chamber 71 includes the gate valves G1 and G2 and the wafer transfer mechanism 8
Is equipped with. Further, the exhaust pipe 72 is provided in the load lock chamber 71.
Is connected, and the exhaust pipe 72 is connected to a vacuum pump 74 via a valve 73.

The transfer mechanism 8 includes, for example, three arms 81.
Drive transmission parts 81a and 82a such as pulleys on which belts are hung in joints between the arms are provided with covers 81b and 82b so as to cover them, and drive for driving the arm 83. The cover 8 covers the mechanism 84 and the drive transmission portion 83a of the drive mechanism 84.
3b is provided. And each cover 81b, 82
arms 8 so that the spaces in b and 83b communicate with each other.
A communication passage 80 is formed in each of the parts 2, 83.

An exhaust pipe 75 is connected to the cover 83b, and the exhaust pipe 75 is connected to the vacuum pump 74 via a valve 76. The valves 73 and 76 are the control unit 9
Is controlled as follows. That is, after the wafer W is loaded into the load lock chamber 71 by the transfer mechanism 8, the valve 76 is opened before opening the valve 73, and the space surrounding the drive transmission parts 81a, 82a, 83a of the transfer mechanism 8 is evacuated. Then, open the valve 73 and load lock chamber 71.
The inside is evacuated. Therefore, the drive transmission units 81a, 82
It is possible to prevent particles generated from a and 83a from scattering in the reaction tube 1.

[0031]

According to the inventions of claim 1 and claim 2,
Since the bearing space of the rotating mechanism, for example, the rotating mechanism utilizing magnetic coupling, is evacuated before the inside of the reaction tube is evacuated,
When the reaction tube is evacuated, scattering of particles from the bearing space is suppressed, and contamination of the object to be processed can be prevented.

According to the third aspect of the present invention, the particles generated from the drive transmission section of the conveying means stay in the cover,
Since the inside of the cover is evacuated to discharge particles and then the inside of the vacuum chamber is evacuated, the scattering of particles into the vacuum chamber can be suppressed.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a vertical heat treatment apparatus of the present invention.

FIG. 2 is a cross-sectional view showing a rotating mechanism according to an embodiment of the vertical heat treatment apparatus of the present invention.

FIG. 3 is a vertical sectional side view showing an embodiment of a vacuum device of the present invention.

FIG. 4 is a sectional view showing a conventional vertical heat treatment apparatus.

[Explanation of symbols]

 1 Reaction Pipe 14 Wafer Boat 15 Gas Supply Pipe 4 Exhaust Pipe 3 Rotation Mechanism 31 Rotation Shaft 5A to 5D Ceramic Bearings 51, 74 Vacuum Pump 61 Inert Gas Supply Pipe 62 Inert Gas Exhaust Pipe 9, 10 Control Unit

Claims (3)

[Claims] 1. A vertical heat treatment apparatus for supporting a holder of an object to be processed by a rotating mechanism via a rotary shaft and performing heat treatment on the object to be processed while rotating the holder in a reaction tube, wherein the reaction In order to evacuate the bearing space in the rotating mechanism that communicates with the inside of the tube, a vacuum evacuation unit having an exhaust port opened in the bearing space, and before the inside of the reaction tube is evacuated, the bearing space is evacuated by the vacuum evacuation unit. A vertical heat treatment apparatus, comprising: a control unit that controls to evacuate. 2. The rotating mechanism is provided with a driven magnet provided on the rotating shaft and a driving magnet for rotating the driven magnet while being magnetically coupled to the driven magnet outside the bearing space. The vertical heat treatment apparatus according to claim 1, wherein: 3. A vacuum processing apparatus in which a transfer means is provided in a vacuum chamber in which an object to be processed is placed, a cover covering a drive transmission part of the transfer means, and a vacuum exhaust for exhausting a space in the cover. A vacuum processing apparatus comprising: a means; and a control unit that controls the space in the cover to be evacuated by the vacuum evacuation means before evacuating the vacuum chamber.