JPH03241730A - Film forming device - Google Patents

Abstract

PURPOSE:To decrease the area of the inner wall face of an inner tube thereby reducing the quantity of the film grown on the inner wall face of the inner tube to prevent the adhesion of foreign matter to a board by providing the wall face of the inner tube with many holes. CONSTITUTION:In an inner tube 11, which consists of quartz tube and is provided inside an outer tube 2, many round holes 11a are provided at the whole wall face. And the inside of the inner tube 11 becomes the reaction chamber for growing a film, and a reaction product grows as a film on the wafer being a substrate within this reaction chamber. But in this case, since many ports 11a are provided at the wall face of the inner tube 11, the area of the inwall of the inner tube 11 is much smaller than the conventional case. For this reason, the quantity of reaction products filming on the inner wall face of the inner tube by the long-term use also becomes small. Hereby, the quantity of foreign matter by the separation of the reaction products on the inner wall face of this inner tube 11 becomes small.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a thin film forming apparatus, for example, a thin film forming apparatus having a double tube structure such as a CVD (chemical vapor deposition) apparatus. It is.

[Prior Art] FIG. 2 is a sectional view of a main part of a low pressure CVD apparatus, which is a diffusion furnace forming film apparatus, as an example of a conventional thin film forming apparatus.

In the figure, code (1) is an inner tube made of quartz tube,
The inside of this inner tube (1) becomes a reaction chamber for film formation. (2)
(3) is a flange ring provided on the outer periphery of one end of the outer tube (2), (4) is a flange ring ( 3
), and this door (4) is provided at a distance from the ends of the inner tube (1) and the outer tube (2). (5) is the inner tube (1) and outer tube (2)
To keep the inside airtight, use the outer tube (2) and flange ring (3).
> between the door (4) and the Francil ring (3), and the O-ring (6) is an exhaust pipe that penetrates the inside and outside of the door (4). An exhaust device (not shown) is connected to the end. (7) is the exhaust pipe (6
) is an exhaust valve installed in the middle.

In the conventional reduced pressure CVD apparatus configured as described above, the interior of the inner tube (1) and the outer tube (2) are simultaneously evacuated by the exhaust device to a vacuum state.

As a step in semiconductor manufacturing, a reaction product is formed into a film on a wafer, which is a substrate, in the reaction chamber of the inner tube (1).

[Problems to be Solved by the Invention] In the conventional thin film forming apparatus configured as described above, reaction products are also formed on the inner wall surface of the inner tube (1) due to long-term use. This reaction product on the inner wall surface peels off and becomes foreign matter, which is present in large numbers inside the inner tube (2), which poses a problem in that it may adhere to the wafer and cause pattern defects in the chip.

This invention was made with the aim of solving the above-mentioned problems, and it is possible to reduce the amount of reaction product film formed on the inner wall surface of the inner tube, thereby preventing foreign matter from forming. An object of the present invention is to obtain a thin film forming apparatus that can prevent the film from adhering to a substrate.

"Means for Solving the Problems" A thin film forming apparatus according to the present invention has a large number of holes provided in the wall surface of an inner tube in which a thin film is formed on a substrate.

[Operation] In the present invention, by providing a large number of holes in the wall surface of the inner tube, the area of the inner wall surface of the inner tube is reduced, and the amount of film formed on the inner wall surface of the inner tube is reduced.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of essential parts of a reduced pressure CVD apparatus showing an embodiment of the present invention, and the same or equivalent parts as in FIG.

In the figure, the code (11) is a quartz tube, and the outer tube (2)
This inner tube (11) is provided inside the
A large number of circular holes (1la) are provided throughout the wall surface. (12) is the O ring (5) attached to the flange ring (3).
), and this door (
12) is also in close contact with the end of the inner tube (11), thereby closing the ends of the outer tube (2) and the inner tube (11) separately.

(13) is the exhaust pipe for the inner pipe drawn out from inside the inner pipe (11) to the outside of the door (12), and (14) is the exhaust pipe for the inner pipe drawn out from the inside of the outer pipe (2) to the outside of the door (12). This is an exhaust pipe for the outer pipe, and these exhaust pipes for the inner pipe and the outer pipe (13),
(14) are combined into one exhaust pipe (20) at one end and connected to an exhaust system (not shown). (15) is an exhaust valve for the inner pipe installed in the middle of the exhaust pipe for the inner pipe (13), and (16) is an exhaust valve for the outer pipe installed in the middle of the two exhaust pipes for the outer pipe (14). be.

In the low pressure CVD apparatus as described above, the inside of the inner tube (11) serves as a reaction chamber for film formation, and a reaction product is formed into a film on a wafer as a substrate in this reaction chamber, as in the conventional case. However, in the case of the device of this embodiment, since a large number of holes (1la) are provided on the wall surface of the inner tube (11), the inner tube (11) has many holes (1la).
The area of the inner wall surface of 11) is considerably smaller than that of the conventional example. Therefore, after long-term use, the inner tube (11
) The amount of reaction products formed as a film on the inner wall surface of the inner tube (11) is also smaller than before, and the amount of foreign matter due to peeling of the reaction products on the inner wall surface of the inner tube (11) is also reduced.

In addition, in the apparatus of this example, the reaction product passes through the hole (1la) and forms a film on the inner wall surface of the outer tube (2).
If the reaction product of this outer tube (2) is peeled off, the inner tube (
1]) acts as a barrier to a certain extent, so that the peeled off reaction products are prevented from entering the reaction chamber as foreign matter.

For these reasons, the apparatus of this embodiment can prevent chip pattern defects due to foreign matter adhering to the wafer, thereby improving device yield.

In addition, in this embodiment, with the inner pipe exhaust valve (15) closed and the outer pipe exhaust valve (16) open, the outer pipe (
2) By exhausting the inside and the inside of the inner tube (11), foreign substances can easily come out from inside the inner tube (11) into the outer tube (2), and the outer tube (
2) Since it is difficult for foreign matter to enter the inner tube (11) from inside, adhesion of foreign matter to the wafer is more reliably prevented.

In the above embodiment, the outer tube (2) and the inner tube (11) are made of quartz tubes, but they are not limited to this, and may be made of other materials.

Further, the shape of the hole (1la) is not limited to a circle, and may be other shapes such as a polygon.

Further, in the above embodiment, the size of the hole (lla) is made smaller as it approaches the end of the inner tube (11), but the size of the hole (lla) may be the same, or They may be different individually and are not particularly limited. In addition, the hole (I
Needless to say, the number of la) is not particularly limited either.

Furthermore, the method of connecting the exhaust device may be conventional.

Further, although the above embodiments have shown a low pressure CVD apparatus for semiconductor manufacturing using a wafer as a substrate, the present invention can also be applied to other FBI film forming apparatuses other than semiconductor manufacturing.

Furthermore, although a horizontal device is shown in the above embodiment, a vertical device may also be used.

[Advantageous Effects of the Invention 1] As explained above, the thin film forming apparatus of the present invention has a large number of holes on the wall surface of the inner tube to reduce the area of the inner wall surface of the inner tube. It is possible to reduce the amount of the reaction product formed into a film, and as a result, it is possible to prevent the reaction product formed into a film on the inner tube from peeling off and adhering to the substrate as foreign matter.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention, and FIG. 2 is a sectional view of a main part of a conventional example. In the figure, (2) is the outer tube, (11) is the inner tube, (1la
) is a hole. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] The inner tube has a wall surface with a large number of holes, and the outer tube surrounds the inner tube. A thin film forming apparatus characterized in that a thin film is formed.