JPH0691018B2 - Optical excitation processor - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement in a photoexcitation processing apparatus for forming a thin film on a substrate by utilizing a photoexcited chemical reaction or etching the substrate surface.

[Technical background of the invention and its problems]

In recent years, a method has been developed in which a chemical reaction by light energy is used to decompose a raw material gas to form a thin film on a sample substrate such as a semiconductor wafer or glass. This method is called an optical CVD method, and has the advantages of being able to form a film at a low temperature and not being damaged by charged particles, as compared with the ordinary film forming method, and will be important in future thin film forming technology. It is attracting attention as one that occupies a position.

FIG. 4 is a schematic configuration diagram schematically showing a conventional photo-CVD apparatus, in which (a) shows a horizontal section and (b) shows a vertical section.
A low-pressure mercury lamp 44 is arranged in a quartz tube 43, and a substrate 46 is placed on the inner surface of an outer cylinder 45. The space between the quartz tube 43 and the outer cylinder 45 is evacuated to the 10 ^-6 [torr] level, and monosilane (SiH ₄ ) and mercury are introduced into this space. Then, the substrate 46 is heated by resistance heating or the like, the mercury lamp 44 is turned on, and the substrate 46 is irradiated with ultraviolet light.
An amorphous silicon film is deposited and formed on the surface of the.

However, this type of device has the following problems. That is, since the light source exists in the central portion, it is necessary to shorten the distance between the quartz tube 43 and the outer cylinder 45 and increase the ultraviolet light intensity on the substrate 46 in order to increase the deposition rate of the thin film. is there. However, if the distance is reduced, the external cylinder
The number of substrates 46 that can be placed on the substrate is reduced. Therefore, it is difficult to process a large amount of substrates in a short time, and there is a problem that it is not suitable for mass production.

[Object of the Invention]

The present invention has been made in consideration of the above circumstances, and an object thereof is to provide a photoexcitation processing apparatus capable of simultaneously processing a large amount of substrates at a high deposition rate or etching rate and improving throughput. To do.

[Outline of Invention]

The essence of the present invention is to improve throughput by using a plurality of light sources and arranging substrates inside and outside the light sources.

That is, the present invention is a photoexcited film forming apparatus that irradiates the surface of a substrate to be processed placed in a source gas atmosphere with light to perform thin film formation, etching, etc. on the surface of the substrate, and is arranged along a uniaxial direction. A central object on which a plurality of substrates to be processed are placed on its outer peripheral surface, a first transparent cylindrical body made of a light-transmitting material and arranged coaxially with the object outside the central object, and a light-transmitting material. And a second transparent cylinder which is made of a material that is arranged coaxially with the cylinder outside the first cylinder, and is arranged coaxially with the cylinder outside the second transparent cylinder. An outer cylindrical body for mounting a plurality of substrates to be processed on its inner surface, and a plurality of light sources arranged between the first and second transparent cylinders for irradiating each of the substrates to be processed with light. It was done.

〔The invention's effect〕

According to the present invention, since the substrates can be arranged inside and outside the space where the light source is arranged, a large number of substrates can be processed at the same time. Furthermore, even if the distance between the light source and the substrate is reduced, a large amount of substrates can be processed as compared with the conventional device. That is, the deposition rate of the thin film or the etching rate of the substrate surface can be increased, and a large number of substrates can be processed at the same time. Therefore, the throughput can be significantly improved.

Further, the deposition rate of the thin film can be changed between the inner side and the outer side with respect to the light source, and the thin film can be simultaneously formed on a plurality of substrates at two types of deposition rates. Further, if the light source is relatively rotated with respect to the central body and the outer cylindrical body, it is possible to prevent the deposition rate from becoming non-uniform due to the non-uniformity of the light intensity.

Example of Invention

 Hereinafter, details of the present invention will be described with reference to illustrated embodiments.

FIG. 1 is a schematic configuration diagram schematically showing a photoexcitation film forming apparatus according to a first embodiment of the present invention, in which (a) shows a cross section and (b) shows a cross section. Reference numeral 11 in the figure denotes a central cylindrical body, and the substrate 16 to be processed is placed on the outer surface of the cylindrical body 11. On the outside of the cylindrical body 11, a first synthetic quartz tube is provided.
The transparent cylinder 12 and the second transparent cylinder 13 having a diameter larger than that of the cylinder 12 are arranged coaxially with the cylinder 11.
A plurality of ultraviolet light sources 14, which are, for example, low-pressure mercury lamps, are arranged between the transparent cylinders 12 and 13. That is, the cylindrical body 12, 13
In between, a plurality of rod-shaped light sources 14 are arranged at equal intervals along the axial direction. An outer cylindrical body 15 is arranged outside the second transparent cylindrical body 13. And this external cylinder
The substrate 16 to be processed is placed on the inner surface of 15.

Next, the operation of the present apparatus configured as described above will be described by taking the formation of amorphous silicon (a-Si) as an example.

First, the space between the central cylindrical body 11 and the first transparent cylindrical body 12
Space between 17 and second transparent cylinder 13 and outer cylinder 15
Evacuate 18 to 10 ^-6 [torr] units each, and these spaces
Monosilane containing 17 and 18 as source gas with mercury (Si
H ₄ ) Gas is introduced at a flow rate of 100 [sccm] and a pressure of 1 [torr]. Then, the substrate 16 is heated to 250 [° C.] by resistance heating or the like, the low-pressure mercury lamp 14 is turned on, and the wavelength is 254 [nm], 185.
The surface of the substrate 16 is irradiated with ultraviolet light of [nm].

As a result, an a-Si film was formed on the substrate 16 with a deposition rate of 3 [μm / h] and a uniformity of ± 10 [%] or less. In this case, the deposition rate is higher than that of the conventional apparatus, so that a desired film thickness can be obtained in a short time, and a large number of substrates can be processed at the same time.

As described above, according to this embodiment, a large number of substrates can be processed at the same time, and a thin film can be formed at a high deposition rate. Therefore, the throughput can be significantly improved. In addition, the distance from the light source 14 of the substrate 16 to the space 17,1
It is also possible to change the deposition rate of the thin film in the spaces 17 and 18 by making them different in 8 or by making the amount of gas introduced into the spaces 17 and 18 different.

FIG. 2 is a vertical sectional view showing the schematic structure of the second embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The difference between this embodiment and the first embodiment described above is that
This is because the transparent cylindrical bodies 12 and 13 to which the light source 14 is attached are rotated. That is, the first and second transparent cylindrical bodies 12, 13
Is a plate body 21, 2 to which the central cylinder body 11 and the outer cylinder body 15 are fixed.
2 is supported via a bearing 23. The structure is rotatable about the axis of the central cylindrical body 11. Since the bearing 23 does not have a vacuum,
Used in combination with O-ring seals. Further, the bottom portions of the transparent cylindrical bodies 12 and 13 are fixed to the disc body 24. The disc body 24 is rotated by the motor 25 as the axis of the central cylindrical body 11.

With such a configuration, the first and second transparent cylindrical bodies 1
By rotating 2, 13, the light source 14 can be rotated. Therefore, even if the light source 14 has uneven emission intensity, the integrated value of the amount of light with which the surface of the substrate 15 is irradiated can be made uniform. Therefore, not only the same effects as those of the first embodiment described above can be obtained, but also there are advantages such that the thin film formation rate can be made more uniform.

FIG. 3 is a vertical sectional view schematically showing the schematic structure of the third embodiment. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

The difference between this embodiment and the first embodiment described above is that
This is because a sealed tube structure was adopted at one end of each cylinder. That is, the bottom opening of the outer cylindrical body 15 is closed by the disc body 31. Similarly for the bottom opening of the central cylindrical body 11,
It is closed by the disc body 32. Furthermore, the first and second
The bottoms of the transparent cylinders 12 and 13 are connected by a hollow disc body 33, and the bottom side of the annular space between the first and second transparent cylinders 12 and 13 is closed.

With such a structure, the raw material gas is introduced from the space 18 between the outer cylindrical body 15 and the second transparent cylindrical body 13, and the space between the first transparent cylindrical body 12 and the central cylindrical body 11 is introduced. Gas can be vented from 17.

With this device, a thin film was formed with a source gas flow rate of 100 [sccm] as in the previous case, a substrate placed on the outer cylindrical body 15 had a deposition rate of 3 [μm / h], uniformity of ± 10 [%] or less, Central cylinder 1
Deposition rate of 2.5 [μm / h] and uniformity of 10 on the substrate placed on 1
[%] Or less a-Si was obtained. At this time, the flow path area of the gas is half that of the first embodiment, so that the amount of gas used can be half even at the same flow rate.

Thus, according to this embodiment, not only the same effects as those of the first embodiment can be obtained, but also the amount of raw material gas used can be halved and the utilization efficiency of raw material gas is improved. There are advantages.

The present invention is not limited to the above-mentioned embodiments. For example, the central object is not limited to a cylinder, but may be a rectangular cylinder, or may not be a cylinder.
However, in order to heat the substrate, the tubular body is preferable because it is easier to provide the heating mechanism. Further, the substrate placed on the central object may be a cylindrical Al substrate or the like. Further, the light source is not limited to the low pressure mercury lamp, but may be a deuterium lamp or the like. Furthermore, conditions such as pressure, gas flow rate and substrate temperature may be appropriately determined depending on the required film thickness and film quality.

The source gas is not limited to monosilane (SiH ₄ ), but other high-order silanes {eg disilane (Si ₂ H ₆ ), trisilane (Si ₃ H ₈ )}, methylsilane-based gas {eg dimethylsilane (SiH _2). (CH ₃ ) ₂ )} or germane type gas {eg germane (GeH ₄ )}. Further, the thin film to be formed is not limited to a-Si, but may be a silicon oxide film, a silicon nitride film, or the like. When forming a silicon oxide film, a silicon nitride film, or the like, nitrous oxide (N ₂ O), ammonia (NH ₃ ) or the like may be mixed with monosilane or the like as a source gas. Alternatively, direct excitation that does not include mercury may be used.

Further, although the thin film formation by the photo CVD method is described in the embodiment, the present invention can be applied to the photoexcitation etching. For example, in a phosphorus-doped poly-Si film grown on a thermally oxidized SiO ₂ film on a Si wafer, a gas containing F and Cl (for example, Cl
₂ ) In, the result of irradiating the ultraviolet light from the Hg-Xe lamp,
Etching rate 0.2 [μm / min], etching uniformity ±
A value of 10% or less was obtained.

In short, the present invention can be variously modified and carried out without departing from the scope of the invention.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram schematically showing a photoexcitation film forming apparatus according to the first embodiment of the present invention, FIG. 2 is a vertical sectional view showing a schematic configuration of the second embodiment, and FIG. 3 is a schematic configuration diagram schematically showing the third embodiment, and FIG. 4 is a schematic configuration diagram schematically showing a conventional device. 11 ... central cylinder (central object), 12 ... first transparent cylinder, 13 ... second transparent cylinder, 14 ... light source, 15 ... external cylinder, 16 ... substrate to be processed, 17,18 …… Space, 21,22 ……
Plate, 23 …… Bearing, 24 …… Disc, 25 …… Motor.

Claims (7)

[Claims] 1. A photo-excitation processing apparatus for irradiating a surface of a substrate to be processed, which is placed in a source gas atmosphere, with light to form a thin film or etch the substrate surface. A central object on which a plurality of substrates to be processed are placed on the outer peripheral surface, a first transparent cylindrical body made of a light-transmitting material and arranged coaxially with the object outside the central object, and transmitting light. A second transparent cylinder made of a material and arranged coaxially with the first cylinder outside the first cylinder;
An external cylinder, which is coaxially arranged with the cylindrical body outside the second transparent cylinder and has a plurality of substrates to be processed mounted on its inner surface, and the first and second transparent cylinders. And a plurality of light sources for irradiating each of the substrates to be processed with light. 2. The optical excitation processing device according to claim 1, wherein the central object is a cylindrical body. 3. The optical excitation processing device according to claim 1, wherein the light source emits ultraviolet light. 4. The light source is arranged in parallel with the central object, and is arranged at equal intervals between the first and second transparent cylinders. The optical excitation processing device according to the item. 5. The claim 1, wherein at least one of the central object and the outer cylindrical body and the light source is rotated about an axis of the central object. Optical excitation processor. 6. The outer cylindrical body is closed at one end, and one of the annular spaces surrounded by the first and second transparent cylindrical bodies is closed. The optical excitation processing device according to claim 1. 7. A source gas is introduced between the outer cylindrical body and the second transparent cylindrical body, and the gas is exhausted between the central body and the first transparent cylindrical body. The optical excitation processing device according to claim 6.