JPS62115708A - Processing device - Google Patents

Abstract

PURPOSE:To enable an inside of a processing chamber to be rinsed with easy structure and without contamination, by rinsing the inside by plasma etching, in which a heating coil is used as a high frequency coil, at a desirable time while using a low pressure chemical gaseous phase growth technique for manufacturing a semiconductor device. CONSTITUTION:With changeover switches S1 and S2 operated, connection of a heating coil 2 is changed from a heating power source 8 to a high frequency power source 9 so that the heating coil 2 is used as a high frequency coil for induction-coupled plasma etching. Etching gas such as nitrogen fluoride (NF3) is supplied as reaction gas 6 and made plasmic by high frequency power applied on the heating coil 2 so that plasma etching reaction can be performed inside a reaction tube 1. Material such as polycrystal line silicon attached to the wall surface or so inside the reaction tube 1 is removed by etching, to rinse the inside into a clean state. Mechanism for carrying plasma-generating electrodes becomes unnecessary, with this structure simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a technology that is effective when applied to processing technology, particularly low-pressure chemical vapor deposition technology used in the manufacture of semiconductor devices.

[Background Art] For example, in a wafer processing step in the manufacture of semiconductor devices, a low-pressure chemical vapor deposition apparatus is sometimes used to form a thin film made of a predetermined substance on the surface of the wafer.

That is, a wafer is placed in a reaction tube made of quartz or the like, the inside of the reaction tube is heated to a predetermined temperature using a heater installed outside the reaction tube, the inside is evacuated to a predetermined degree of vacuum, and then the inside of the reaction tube is evacuated to a predetermined degree of vacuum. By supplying a reactive gas, a substance precipitated from the reactive gas is deposited on the surface of the wafer to form a predetermined thin film.

In this case, it is unavoidable that substances deposited from the reaction gas adhere to the inner walls of the reaction tube exposed to the reaction gas, and foreign matter generated from the substances adhering to the inside of the reaction tube contaminates the wafer. In order to prevent this, it is necessary to periodically clean the inside of the reaction tube to remove the broken substances.

For this purpose, for example, a plasma generating electrode connected to a high frequency power source is inserted into the open end of the reaction tube, and a predetermined etching gas is supplied to perform reactive plasma etching, thereby causing the etching to adhere to the inside of the reaction tube. It is possible to remove the removed substances by etching.

However, in the above cleaning method, the plasma generation electrode is inserted directly into the reaction tube, so when the reaction tube is at a relatively high temperature, such as immediately after film formation on a wafer, the plasma Contamination of the inside of the reaction tube by metal elements constituting the generation electrode is unavoidable, and furthermore, the open end of the reaction tube is usually equipped with complex mechanisms such as soft landings for inserting and removing wafers. The inventors of the present invention have found that there are various problems, such as not only the connection between the plasma generation electrode and the high frequency power source being technically difficult, but also the need for a complicated mechanism to transport the plasma generation electrode.

A document that describes the low-pressure chemical vapor deposition technology used in the manufacture of semiconductor devices is "RTM Materials J I" published by Kogyo Kenkyukai Co., Ltd. on November 15, 1980.
983 + January issue 1ff) P69-P74.

[Object of the Invention] An object of the present invention is to provide a processing technique that has a simple structure and can perform cleaning without contaminating the inside of the processing chamber.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Summary of the Invention] A brief overview of typical inventions disclosed in this application is as follows.

That is, a high-frequency power source is provided together with a heating power source that energizes a heating coil wound outside the processing chamber, and a switching mechanism switches the connection of the heating power source or the high-frequency power source to the heating coil, so that the heating can be performed at a desired time. The inside of the processing chamber is cleaned by plasma etching using the heating coil as a high frequency coil.
It has a simple structure and allows cleaning to be performed without contaminating the inside of the processing chamber.

[Embodiment] FIG. 1 is an explanatory diagram showing the main parts of a processing device that is an embodiment of the present invention.

In this embodiment, the apparatus is used as a low-pressure chemical vapor deposition apparatus for forming a thin film made of a predetermined substance on a wafer (workpiece) made of a semiconductor or the like.

That is, a heating coil 2 is wound around the outer periphery of a reaction tube l (processing chamber) made of quartz or the like, and by energizing the heating coil 2, the inside of the reaction tube 1 is heated to a predetermined temperature. It is composed of

One end of the reaction tube l is connected to a vacuum pump 3 to evacuate the inside to a desired degree of vacuum, and the other end is provided with a gas injector 4, which is connected to a reaction gas supply source 5. The structure is such that a reaction gas 6 having a desired configuration is supplied.

Further, a lid 7 is detachably provided at the other end of the reaction tube 1, and is configured so that a wafer (not shown) can be inserted into and taken out of the reaction tube 1. ing.

In this case, a high frequency type s9 is provided together with a heating power source 8 that supplies electricity to the heating coil 2, and by appropriately operating the changeover switch 31 (switching mechanism) and the changeover switch S2 (switching mechanism), the heating coil 2 can be heated at a desired time. heating type r
The structure is such that the connection of A8 and the high frequency power source 9 to the heating coil 2 can be switched.

The operation of this embodiment will be explained below.

Normally, the heating coil 2 is connected to the heating TF1'6fX8 by means of changeover switches Sl and S2.

Then, by energizing the heating coil 2, the reaction tube 1 is heated.
A wafer (not shown) inserted into the tube is heated to a predetermined temperature, and the inside of the reaction tube 1 is evacuated to a predetermined degree of vacuum. Gas 6 is supplied.

Then, polycrystalline silicon is deposited on the surface of the wafer by thermal decomposition of monosilane, etc., and mFI made of polycrystalline silicon is formed.Then, the wafer is taken out of the reaction tube l. The precipitation of polycrystalline silicon and the like due to the thermal decomposition of the reaction gas 6 is...
polycrystalline silicon etc. are deposited on the inner wall surface of the reaction tube 1, and after the film formation process on the wafers as described above is repeated a predetermined number of times, A cleaning operation is required to remove substances attached to the inside.

At that time, in this embodiment, the changeover switches S1 and S2 are operated to change the connection of the heating coil 2 to heating T1. Source 8
to the high frequency power source 9, and the heating coil 2 to 33i
It is used as a high frequency coil for coupled plasma etching, and as a reactive gas 6, for example, nitrogen fluoride (
NF3) or other etching gas is supplied, and the heating coil 2
A plasma etching reaction can be carried out inside the reaction tube 1 by turning it into plasma with the high frequency power applied to it, and materials such as polycrystalline silicon attached to the inner wall of the reaction tube 1 are etched away. and cleaned to a clean condition.

As described above, in this embodiment, the connection to the heating coil 2 is switched from the heating power source 8 to the high frequency power source 9 using the changeover switches S1 and S2, and the heating coil 2 is used as a high frequency coil for inductively coupled plasma etching. Since the inside of the reaction tube 1 can be cleaned by etching, for example, a transport mechanism for the plasma generation electrode is not required, simplifying the structure, and the reaction tube 1 can be cleaned immediately after film formation on a wafer. Even when performing cleaning operations at relatively high temperatures, there is no lη staining caused by metal elements inside the reaction tube 1 due to insertion of the plasma generating electrode, etc. lt
Clean cleaning can be performed.

Furthermore, since it is inductively coupled plasma etching, the plasma density is high in areas where there is a relatively large amount of deposits to be removed, such as the inner wall surface of the reaction tube 1 close to the heating coil 2, and a higher etching rate can be obtained. Therefore, the cleaning process [■■] inside the reaction tube 1 can be carried out quickly and effectively.

[Effects] (1) A processing device that supplies a processing fluid to perform predetermined processing while heating a processing object located inside the processing chamber by energizing a heating coil wound outside the processing chamber. and a heating power source that energizes the heating coil, a high frequency power source, and a switching mechanism that switches the connection of the heating power source or the high frequency power source to the heating coil,
By using the heating coil as a high-frequency coil for inductively coupled plasma etching, the inside of the processing chamber can be cleaned by plasma etching, and the structure is similar to cage 1.
Cleaning can be performed without contaminating the inside of the processing chamber.

(2) As a result of (1) above, the plasma density becomes high in areas where there is a relatively large amount of deposits to be removed, such as the inner wall surface of the processing chamber near the heating coil, and a higher etching rate is obtained. The interior of the room is cleaned quickly and effectively.

(3) As a result of (1) above, contamination of wafers subjected to film formation processing in the processing chamber is prevented, and yields are improved.

(4), above +11. (As a result of 21, the operating rate of a low-pressure chemical vapor deposition apparatus used for film formation processing on wafers in the manufacture of semiconductor devices is improved.

Although the invention made by the present inventor has been specifically explained based on Examples above, the present invention is not limited to the Examples described above, and it is possible to make various changes without departing from the gist thereof. Not even.

For example, it is also possible to provide a plurality of heating coils.

[Field of Application] In the above explanation, the invention made by the present invention H is mainly explained in the case where it is applicable to the low pressure chemical vapor deposition technology which is the field of application which is the background of the invention, but the present invention is not limited to this. Expands to techniques that use qi + [1 reaction (
It can be used.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing the main parts of a processing device 6, which is an embodiment of the present invention.

1... Reaction tube (processing chamber), 2... Heating coil, 3...
...Vacuum pump, 4...Gas injector, 5...
Reaction gas supply source, 6... Reaction gas (processing fluid), 7.
... Lid body, 8 ... Heating power supply, 9 ... High frequency power supply, 3
1. S2... Selector switch (cutting mechanism).

Agent Patent Attorney / J'Jl+ Katsuo, ゛ Haku'
\,・,−1/ Figure 1

Claims (1)

[Claims] 1. A processing device that performs predetermined processing by supplying a processing fluid while heating a processing object located inside the processing chamber by energizing a heating coil wound outside the processing chamber, A processing device comprising: a heating power source that energizes the heating coil; a high frequency power source; and a switching mechanism that switches connection of the heating power source or the high frequency power source to the heating coil. 2. Claim 1, wherein the processing device is a low-pressure chemical vapor deposition device.
Processing equipment described in Section 1.