JP2509817B2 - Processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a processing apparatus.

(Prior Art) Conventionally, as a mounting table for mounting and heating an object to be processed, such as a semiconductor wafer, in a processing apparatus such as a vapor phase growth apparatus or an annealing apparatus, the heat resistance is high and the thermal conductivity is large. A mounting table made of a material such as carbon is used. JP-A-60-136221, JP-A-61-220420, and JP-A-61-229320
JP-A-61-247685, JP-A-62-73621 and the like.

In general, since the temperature distribution of the mounting surface of the mounting table is unlikely to be uniform, the temperature distribution of the mounted semiconductor wafer substrate is non-uniform, and the non-uniform heat distribution results from the non-uniform temperature distribution. Causes internal stress in the semiconductor wafer substrate, causing warpage of the semiconductor wafer substrate, generation of crystal defects due to dislocations called slip lines, and nonuniform film thickness during processing such as vapor phase growth.

Therefore, in order to improve the uniformity of the temperature distribution of the mounting table,
A material having a high thermal conductivity such as carbon is used for the mounting table, and a heat insulating cover for preventing radiation is attached to the side surface of the mounting table so as to prevent heat from escaping due to radiation from the lateral direction of the mounting table.

(Problems to be Solved by the Invention) However, the use of a material having a high thermal conductivity for the mounting table cannot prevent the escape of heat due to radiation, which causes a problem that the temperature distribution of the mounting table becomes uneven. It was

Also, even if a heat insulating cover for preventing radiation is attached to the side of the mounting table, it is not possible to prevent the escape of heat due to radiation from the mounting surface, so the mounted body is replaced when processing the mounted body continuously. If the temperature of the mounting table drops significantly below the desired temperature,
There is also a problem in that the temperature distribution of the mounting table is greatly nonuniform depending on whether the mounted body is mounted or not mounted.

The present invention has been made in consideration of the above points, and prevents the heat from escaping from the mounting table and improves the temperature uniformity, so that the object to be processed placed on the mounting table is maintained at a uniform temperature. It is to provide a processing device for processing at.

[Structure of Invention]

(Means for Solving Problems) The present invention relates to a processing apparatus for processing an object to be processed placed on a mounting table in a processing chamber, exposing a surface of the mounting table facing the object to be processed. The heat insulating portion covers the mounting surface of the mounting table other than the surface facing the object and the side surface of the mounting table.

The heat insulating portion has a heat emissivity of a portion that covers the other mounting surface of the mounting table is equal to that of the target object, and a heat emissivity of the portion that covers the side surface of the mounting table is smaller than that of the target object. It is preferable to configure so that

Further, the present processing apparatus is particularly suitably applied to a processing apparatus configured to heat the mounting table from the exposed back surface side by a plurality of light irradiation means. In that case, it is particularly preferable that the mounting table is made of a material having a crystallographic direction parallel to the mounting surface of the object to be processed and having an anisotropic crystal structure.

(Operation) In the processing apparatus according to the present invention, the processing object facing surface of the mounting surface of the mounting table is exposed, and the mounting surface of the mounting table other than the processing object facing surface and the mounting table. Since the side surface of the mounting table is covered with a heat insulating part, the escape of heat due to radiation can be prevented to a minimum, and in particular, the temperature of the mounting table can be prevented from lowering when the object to be processed is replaced, and it can be mounted on the mounting table. It is possible to improve the temperature distribution uniformity of the object to be processed.

In addition, for example, the heat emissivity of the portion of the mounting surface of the mounting table that covers the mounting surface other than the surface facing the object to be processed is made equal to that of the object to be processed, and covers the side surface of the table. If the heat emissivity of the part is configured to be smaller than that of the object to be processed, in particular, when the object to be processed is placed on the mounting table, the rate of escape of heat from the mounting surface is made constant, and the escape of heat from the side surface is prevented. Since it can be minimized, the temperature distribution uniformity of the object to be processed placed on the mounting table can be improved.

The present invention particularly heats the mounting table from the exposed rear surface side thereof by a plurality of light irradiation means such as an infrared lamp,
If the back surface of the mounting table is uniformly heated and applied to a processing apparatus that processes the object by heat transfer, the temperature distribution uniformity of the object can be further improved. In that case,
If the mounting table is made of a material such as carbon having a crystallographic direction parallel to the mounting surface of the object to be processed and having an anisotropic crystal structure, the heat from the back surface, which is uniformly heated, can be transferred from the side surface. It is possible to transmit the object to the object to be processed uniformly and with good responsiveness while suppressing the escape to the minimum.

(Example) Hereinafter, the processing apparatus of the present invention will be used in a CVD (Che
An embodiment applied to a mical vapor deposition apparatus will be described with reference to the drawings.

A window (2) made of quartz is sandwiched by a pressing plate (3) in the chamber (1) above the airtight chamber (1) made of cylindrical Al so as to keep the chamber (1) airtight. . A plurality of infrared ray lamps (infrared ray lamps) (4) that can be heated by infrared rays are provided below the chamber (1) so as to intensively heat the same plane by a reflecting mirror (5).

A quartz heating window (6) is provided under the chamber (1) facing the IR lamp (4) and the chamber (1) so that infrared rays are introduced into the airtight chamber (1). And is sandwiched in the chamber (1).

Inside the chamber (1), there is provided a column-shaped mounting table (9) on which the semiconductor wafer (8) which is the object to be processed is mounted. The mounting table (9) is made of a material having high thermal conductivity and good heat resistance, for example, carbon, and the crystal structure of the material is anisotropic, and the crystal structure is parallel to the mounting surface (10). Have. Here, the cylindrical heat insulating part (12) is provided so as to expose the surface of the mounting surface (10) facing the mounted body and cover the other mounting surface (10) and the side surface (11). The stand (9) is supported in the chamber (1) and is placed so that it can be heated by the IR lamp (4) through the heating window (6). In this heat insulating part (12), for example, the heat emissivity of the portion that covers the mounting surface (10) other than the object-opposing surface is the same as that of the object, and the heat of the part that covers the side surface (11) is the same. Has a lower emissivity than that of the object to be processed.

Further, a gas introduction hole (13) for outflowing a reaction gas for processing is provided in the upper part of the side wall of the chamber (1), and a vacuum state is formed in the chamber (1) at the lower part of the side wall of the chamber (1). As described above, the exhaust hole (14) is provided. Moreover,
The chamber (1) is provided with an opening / closing mechanism (not shown) capable of carrying in and out the semiconductor wafer (8) which is the object to be processed,
The semiconductor wafer (8) can be transferred by a transfer mechanism (not shown).

Then, the CVD apparatus having the above configuration is controlled in operation and setting by a controller (not shown).

Next, processing of the semiconductor wafer (8) by the above-mentioned CVD device will be described.

First, the opening / closing mechanism (not shown) is opened, and the semiconductor wafer (8) is loaded into the chamber (1) by a transfer mechanism (not shown) and placed on the mounting table (8). At this time, centering and orientation flat alignment of the wafer (8) are performed in advance by a mechanism (not shown) inside or outside the chamber (1) and the wafer (8) is placed at a predetermined position.
Is placed.

Then, the opening / closing mechanism (not shown) is closed to make the chamber (1) airtight, and the chamber (1) is evacuated to a desired vacuum state by exhausting air from the exhaust hole (14).

Then, by the IR lamp (4) through the heating window (6),
From the bottom surface of the mounting table (9) to a desired temperature, for example 500 ° C to 1200
Heat to about ℃.

Here, in the heating using the plurality of IR lamps (4) and the reflecting mirror (5), the back surface of the mounting table (9) can be heated fairly uniformly, but it cannot be heated completely evenly. A temperature gradient occurs on the back surface of the stand (9). Therefore, when a material having uniform heat conductivity in the parallel and vertical directions to the mounting surface (10), such as isotropic carbon, is used for the mounting table (9), the thickness of the mounting table (9) is The temperature distribution on the mounting surface (10) was not uniform unless the thickness was made thicker. However, in the mounting table (9) of this example, the crystal structure of the material was made anisotropic so that the thermal conductivity of Since the anisotropy was used, the mounting table (9) which is thin and has good temperature uniformity is realized.

For example, carbon with high thermal conductivity generally has a thermal conductivity in the direction parallel to the crystal axis of 108 to 180 (Kcal / mh ° C) and a thermal conductivity in the direction perpendicular to the crystal axis of 72 to 108 (Kcal / mh ° C). ) Therefore, the heat applied to the lower surface of the mounting table (9) is changed by the anisotropic crystal structure having the crystal direction parallel to the mounting surface (10) direction of the mounting table (9). Side) than transmitted to () (11)
Since the heat is quickly transferred in the direction, when the heat is transferred to the mounting surface (10), the temperature becomes uniform on the entire mounting surface (10). As a result, the temperature distribution of the semiconductor wafer (8) is made uniform, and the film thickness of the grown crystal on the surface of the wafer (8) is improved. Further, it is not necessary to make the mounting table (9) thick, and a thin and compact mounting table (9) is possible, and the wafer (8) can be heated quickly and uniformly. Moreover, since the mounting table (9) can be made thin, the temperature of the mounting surface (10) can be made uniform when the amount of heat from the IR lamp (4) is changed, such as when the temperature of the wafer (8) is changed depending on the processing content. The thermal responsiveness that secures the property is also improved. Also, heat escape from the side surface (11) can be reduced.

Further, since the mounting table (9) is covered with the heat insulating portion (12) on the mounting surface (10) and the side surface (11) other than the surface of the mounting surface (10) facing the object to be processed, The escape of heat due to the radiation of the mounting table (9) can be prevented to a minimum, the temperature drop of the mounting table (9) can be prevented, and the temperature distribution uniformity can be improved. In particular, when the wafers (8) are exchanged when the semiconductor wafers (8) are continuously processed, the temperature of the mounting table (9) can be prevented from lowering. Further, by making the emissivity of heat of the portion covering the mounting surface (10) other than the object-opposing surface constituting the heat insulating part (12) equal to that of the semiconductor wafer (8) which is the object to be processed. Since the heat is uniformly dissipated from the entire mounting surface (10) and the temperature distribution on the mounting surface (10) during processing is uniform, the film uniformity of the grown crystal on the surface of the semiconductor wafer (8) is uniform. Is improved, and stable crystal growth can be performed. Moreover, since the heat emissivity of the portion covering the side surface (11) of the heat insulating portion (12) is smaller than that of the semiconductor wafer (8) which is the mounted body, the heat from the side surface (11) is reduced. Of the mounting table (9) and the temperature of the mounting table (9) can be prevented from decreasing. For example,
In this embodiment, the object to be processed is a semiconductor wafer (8),
When the processing temperature is about 600 ° C., the emissivity of the wafer (8) is about 0.1. Therefore, the heat insulating material (12) is composed of SUS or tantalum, which is a base material having heat resistance and low thermal conductivity, Mounting surface (1
The front and back of the 0) side are coated with platinum, etc., which has an emissivity of about 0.1 at 600 ℃, and the front and back of the side (11) side are coated with silver etc.
It is advisable to coat the coating with emissivity lower than 0.1 at 0 ° C.

Next, a reaction gas such as disilane is introduced into the surface of the semiconductor wafer (8) heated to a desired processing temperature through the gas introduction hole (13),
A polysilicon crystal film or the like is grown on the wafer (8). Here, UV (Vltraviolet) light may be introduced through the window (2) to promote the reaction on the wafer (8).

Then, the processed semiconductor wafer (8) is unloaded from the chamber (1) by an opening / closing mechanism (not shown) and a transfer mechanism (not shown), and the processing is completed.

Further, although the material of the semiconductor wafer mounting table (9) of the above-described embodiment is described as carbon, it is sufficient if the material has the anisotropic crystal structure and the thermal conductivity is anisotropic. It is needless to say that the crystal structure may be parallel or perpendicular to the mounting surface (10) depending on the anisotropic direction of thermal conductivity.

The heat insulating part (12) of the above-described embodiment has been described in the case where the object to be processed is the semiconductor wafer (8) and the processing temperature is 600 ° C. However, other than the surface of the mounting surface (10) facing the object to be processed. Anything can be used as long as it can insulate the mounting surface (10) and side surface (11) of
The invention is not limited to the above embodiment. Further, it goes without saying that the emissivity of the heat insulating section (12) also differs depending on the processing set temperature and the material of the mounted body.

Further, in the above-mentioned embodiment, the CVD device in the semiconductor manufacturing process is explained, but any process for mounting and heating a semiconductor wafer to grow a crystal on the semiconductor wafer can be applied, such as an epitaxial device, an annealing device, an oxide film. It goes without saying that anything such as a forming device can be applied.

As described above, according to this embodiment, the semiconductor wafer (8) is mounted on the mounting table (9) in the airtight chamber (1) and the crystal is grown on the surface of the semiconductor wafer (8). At that time, since the heat insulating portion (12) for covering the mounting surface (10) and the side surface (11) other than the surface of the mounting surface (10) of the mounting table (9) facing the object to be processed is provided, It is possible to prevent heat from escaping due to the radiation of the mounting table (9), prevent the temperature of the mounting table (9) from decreasing, and achieve uniform temperature distribution. Also, multiple IRs
The back surface of the mounting table (9) is uniformly heated by the lamp (4), and the material of the mounting table (9) is set to the object mounting surface (1
(0) has a crystal direction parallel to that of (1) and is made of a material having an anisotropic crystal structure.
The temperature uniformity and thermal response of 0) can be further improved.

[Effects of the Invention] According to the present invention as described above, it is possible to prevent heat from escaping from the mounting table on which the object to be processed is placed, and to improve the temperature uniformity of the object to be processed. The object to be processed can be stably processed, and the yield of the object to be processed due to the processing can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment in which the processing apparatus of the present invention is applied to a CVD apparatus. In the figure, 1 ... Chamber, 4 ... IR lamp, 8 ... Semiconductor wafer, 9 ... Mounting table, 10 ... Mounting surface, 11 ... Side surface, 12 ... Insulation section

Claims (3)

(57) [Claims] 1. A processing apparatus for processing an object to be processed placed on a mounting table in a processing chamber, wherein a surface of the mounting table facing the object to be processed is exposed to expose the mounting surface of the mounting table. A processing device, wherein a mounting surface other than the surface facing the object to be processed and the side surface of the mounting table are covered with a heat insulating portion. 2. The heat insulating portion has a heat emissivity of a portion covering the other mounting surface is equal to that of the object to be processed, and a heat emissivity of a portion covering the side surface is smaller than that of the object to be processed. The processing device according to claim 1, wherein 3. The mounting table is heated from the exposed back surface side by a plurality of light irradiation means, and the mounting table has a crystallographic direction parallel to a mounting surface of the object to be processed. The processing apparatus according to claim 2, wherein the processing apparatus is formed of a material having an anisotropic crystal structure.