JP2928013B2 - Vapor phase growth apparatus and cleaning method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to a vapor phase growth apparatus and
Respect to its cleaning method, structure and its cleaning side of the reaction chamber of the vapor deposition apparatus to reduce the maintenance frequency due to removal of product in particular attached to the exhaust passage inner wall
It is about the law .

[0002]

2. Description of the Related Art FIG. 3 is a schematic sectional view showing an example of a reaction chamber of a conventional vapor phase growth apparatus. In FIG. 3, reference numeral 1 denotes a reaction chamber for forming a thin film on a semiconductor wafer 2; A wafer stage provided with a heater for mounting and holding the semiconductor wafer 2 and heating the semiconductor wafer 2, a gas head 4 for introducing a reaction gas and a replacement inert gas into the reaction chamber 1, and a wafer head 5. An exhaust path 6 provided on the outer peripheral portion surrounding the stage 3 is provided between the exhaust path 5 and the exhaust port 7 so that the gas in the reaction chamber 1 can smoothly flow through the exhaust path 5 to the exhaust port 7. Evacuated chamber. Here, in the exhaust path 5, the dimension of A is increased to increase the effective area so that the gas in the reaction chamber 1 is smoothly exhausted.

Next, the operation of the conventional vapor phase growth apparatus shown in FIG. 3 will be described. First, after the semiconductor wafer 2 is mounted on the wafer stage 3, the inside of the reaction chamber 1 is evacuated to a high vacuum through an exhaust port 7 by an exhaust device (not shown). Next, the semiconductor wafer 2 is heated to a predetermined temperature by a heater built in the wafer stage 3, and a reaction gas is ejected from the gas head 4 to the main surface of the semiconductor wafer 2 attached to the wafer stage 3. The reaction gas that has reached the main surface of the semiconductor wafer 2 undergoes a chemical reaction by thermal energy, and a reaction product is deposited on the main surface of the semiconductor wafer 2 to form a thin film.

The unreacted reaction gas flows radially in the exhaust path 5 as shown by arrows in FIG. 4, and is exhausted to the outside through the exhaust port 7 through the exhaust chamber 6. At this time,
The reaction gas heated to a high temperature is cooled in the exhaust path 5, and as shown in FIG. 5, flake-like or powder-like products 8 are deposited on the inner walls of the exhaust path 5 and the exhaust chamber 6. Finally, when the formation of the thin film on the semiconductor wafer 2 is completed, an inert gas for replacement, such as nitrogen gas, is spouted from the gas head 4 instead of the reaction gas, and the unreacted reaction gas remaining in the reaction chamber 1 is exhausted. Then, the thin film forming step is completed.

[0005]

Since the conventional vapor phase growth apparatus is configured as described above, the products 8 are deposited on the inner walls of the exhaust path 5 and the exhaust chamber 6 to cause Since the gas flow changes, the uniformity of the film thickness formed on the semiconductor wafer 2 is impaired, or the deposited product 8 is peeled off and affects the film characteristics formed on the semiconductor wafer 2. It is necessary to periodically stop the apparatus, open the reaction chamber 1 to the atmosphere, remove components to which the product 8 is attached, and remove the product 8, which requires labor and increases costs. There was a problem that the operation rate of the system was reduced.

[0006] The present invention has been made to solve the above problems, to remove the product deposited on the inner wall of the exhaust path, the vapor phase growth apparatus of the less costly can be reduced maintenance frequency of the device and The purpose is to obtain the cleaning method .

[0007]

A vapor phase growth apparatus according to the present invention reduces the effective area of an exhaust passage so as to reduce the effective area of the exhaust passage.
Exhaust path around the reaction chamber to increase the gas flow velocity
It is provided with an elevating unit that is provided to be able to move up and down .
Further, a method of cleaning a vapor phase growth apparatus according to the present invention
Indicates that the exhaust path around the reaction chamber
Inert into the reaction chamber from the gas head by reducing the effective area
A flow of the inert gas that introduces gas and flows through the exhaust path
By increasing the speed, it adheres to the inner wall of the exhaust path.
The exhausted product is exhausted to the outside together with the inert gas.
It is something to do.

[0008]

According to the present invention, in the cleaning step, the effective area of the exhaust path is reduced, the gas flow velocity in the exhaust path is increased, and this high-speed gas flow acts to remove the reactant adhering to the inner wall. .

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a schematic sectional view showing one embodiment of a reaction chamber in a vapor phase growth apparatus of the present invention. In the figure, the same or corresponding parts as those of the conventional vapor phase growth apparatus shown in FIG. , The description of which is omitted. Reference numeral 9 denotes an elevating unit provided around the reaction chamber and provided at the bottom of the evacuation path 5. The elevation of the elevating unit 9 reduces the effective area of the evacuation path 5. Although the drive mechanism of the elevating unit is not particularly shown, it is driven by electric power, hydraulic pressure, pneumatic pressure, or the like as a power source, and is moved up and down through screws and racks, or may be a bellows or the like.

Next, the operation of the vapor phase growth apparatus of the present invention shown in FIG. 1 will be described. The step of forming a thin film on the semiconductor wafer 2 is performed in the same manner as in the conventional vapor phase growth apparatus shown in FIG. At this time, the product 8 is also deposited and adhered to the inner wall of the exhaust path 5.

Here, the step of cleaning the product 8 will be described. As shown in FIG. 2, the elevating section 9 is raised to reduce the effective area of the exhaust path 5, and the same amount of inert gas for replacement as when exhausting the residual reaction gas in the reaction chamber 1 in the thin film forming step is supplied to the gas head. 4 to the reaction chamber 1.
Then, the replacement inert gas in the reaction chamber 1 is exhausted through the exhaust port 7 by the exhaust device. Since the exhaust path 5 has a smaller effective area, the flow velocity of the gas flow in the exhaust path 5 increases, and the high-speed gas flow blows off the products 8 attached to the inner wall of the exhaust path 4, The air is exhausted from the exhaust port 7 to the outside.

For example, if the diameter of the gas head 4 is 150 m
When m and A are 10 mm, the effective area of the exhaust path 5 is 4
700 mm ² (150 × 10 × π). In this state, the thin film forming step is performed, and the elevating unit 9 is raised to set A to 0.5 mm.
mm and the effective area of the exhaust path 5 is 230 mm ² (15
When the cleaning step was performed with a reduction of 0 × 0.5 × π), the product 8 was effectively removed.

As described above, by periodically performing the cleaning step, the cleaning process is stopped, the reaction chamber 1 is opened, and the product 8 is removed. Product 8 can be removed, and a thin film can be formed on the semiconductor wafer 2 with good reproducibility.

In the above embodiment, the wafer stage 3
Is described using a wafer face-down structure in which the gas head 4 is disposed on the upper side and the wafer stage 3 is disposed on the lower side, and the wafer face-up structure in which the gas head 4 is disposed on the upper side. The same effect can be obtained.

In the above embodiment, the flow rate of the inert gas for replacement in the cleaning step, for example, the nitrogen gas is described as the same as the flow rate at the time of evacuation. However, the flow rate of the inert gas for replacement in the cleaning step is further increased. Then, the product 8 can be more effectively removed.

Further, in the above-described embodiment, the same inert gas for replacement, for example, nitrogen gas is used in the thin-film forming process when the residual reaction gas in the reaction chamber 1 is exhausted and in the cleaning process. The active gas may be different.

Further, in the above embodiment, the process of forming a thin film on the semiconductor wafer 2 and the cleaning process are described as separate processes.
The same effect can be obtained even if the cleaning step is performed when the residual reaction gas in the inside is exhausted.

[0018]

As described above, according to the present invention, the effective area of the exhaust path is reduced in the cleaning step so that the gas flow velocity in the exhaust path is increased, so that the deposition adheres to the inner wall of the exhaust path. Automatically removes the product
A low-cost vapor-phase growth apparatus and a low-cost apparatus that can form thin films on semiconductor wafers with good reproducibility and reduce equipment maintenance frequency.
And its cleaning method can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a reaction chamber by a vapor phase growth apparatus of the present invention.

FIG. 2 is a schematic sectional view illustrating a cleaning operation of the vapor phase growth apparatus of the present invention shown in FIG.

FIG. 3 is a schematic sectional view showing an example of a reaction chamber of a conventional vapor phase growth apparatus.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

5 is a schematic cross-sectional view showing a state of attachment of a reactant by the conventional vapor phase growth apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction chamber 2 Semiconductor wafer 3 Wafer stage 4 Gas head 5 Exhaust path 9 Lifting part

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 21/205 H01L 21/31

Claims (2)

(57) [Claims] 1. A reaction chamber, a wafer stage disposed in the reaction chamber for mounting and holding a semiconductor wafer, and disposed in the reaction chamber opposite to a main surface of the semiconductor wafer mounted on the wafer stage. Gas head,
An exhaust path for replacing a reaction gas in the reaction chamber with an inert gas provided on an outer peripheral portion surrounding the wafer stage; introducing a reaction gas from the gas head into the reaction chamber; In a vapor phase growth apparatus for forming a thin film, the effective area of the exhaust path is reduced.
In order to increase the gas flow rate in the exhaust path, the reaction
Vapor deposition apparatus characterized by comprising said lifting portion provided vertically movable within the exhaust path around the chamber. 2. A reaction chamber, wherein said reaction chamber is provided in said reaction chamber,
A wafer stage for mounting and holding a conductive wafer;
The main part of the semiconductor wafer attached to the wafer stage
A gas head disposed in the reaction chamber facing the surface,
The reaction device is provided on an outer peripheral portion surrounding the wafer stage.
Exhaust path to replace indoor reaction gas with inert gas
And reacting gas from the gas head into the reaction chamber.
To form a thin film on the semiconductor wafer.
Cleaning method for cleaning long equipment
Sometimes, the effective cross-sectional area of the exhaust path around the reaction chamber is reduced.
Inert gas from the gas head into the reaction chamber
And reduce the flow rate of the inert gas flowing in the exhaust path.
By increasing the speed, the air adhering to the inner wall of the exhaust path
To the outside together with the inert gas.
Cleaning method for vapor phase epitaxy apparatus
Law.