JP3548634B2 - Film forming apparatus and method for removing deposited film in the apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a film forming apparatus for forming a thin film or the like on a silicon wafer used for manufacturing a semiconductor device, and more particularly to the removal of a deposited film by a reaction gas in a reaction vessel used in the film forming apparatus.
[0002]
[Prior art]
In a film forming apparatus of this type or a heating apparatus, particularly, a so-called hot wall (CVD) type CVD apparatus, as the film forming reaction progresses in a quartz reaction vessel, a quartz jig surface of the reaction vessel or the like is formed. A film containing a metal halide or the like is deposited. Then, as it is, particles are generated due to degassing or peeling from such a deposited film. In order to prevent this, when the deposition amount of the deposited film reaches a certain level with the quartz jig, the deposited film is removed.
[0003]
Conventionally, for example, by introducing an etching gas (preferably ClF3) into a reaction vessel to remove such a deposited film, it is possible to remove the film deposited in the deposition chamber. . According to this method, compared to the conventional method of disassembling a reaction vessel and immersing it in a chemical solution to perform cleaning, cleaning can be performed in a short time by an amount that makes dismantling of the reaction vessel unnecessary. it can. In this case, the cleaning time by the etching is performed for a predetermined time according to the thickness of the deposited film to be removed.
[0004]
[Problems to be solved by the invention]
However, in such a conventional film forming apparatus, particularly in the method of removing the deposited film, there is a difference between the monitor film thickness and the film thickness actually adhering to the reaction vessel, or the reaction in the reaction vessel is uneven. Due to the nature and the like, it is difficult to accurately grasp the required etching amount before starting the cleaning. In addition, during cleaning, the container is heated to cause an etching reaction, or the container is kept airtight so that the etching gas does not leak to the outside of the container. Therefore, it is impossible to determine the end of the cleaning.
[0005]
As described above, while it is possible to wash the inside of the reaction vessel without dismantling the reaction vessel, it is practically impossible to disassemble the reaction vessel and observe the inside of the vessel. Therefore, in the actual cleaning operation, it is necessary to set the cleaning time by etching longer for safety. Since it is difficult to confirm whether or not the cleaning is sufficiently performed, etching is performed more than necessary. As a result, there are problems such as prolonged downtime of the apparatus or consumption of the quartz reaction tube. Had occurred.
[0006]
Therefore, an object of the present invention is to provide a film forming apparatus capable of efficiently and accurately removing a deposited film in a reaction vessel.
[0007]
[Means for Solving the Problems]
The film forming apparatus according to the present invention is a film forming apparatus that accommodates a substrate on which a film is to be formed in a reaction vessel and forms a film on the substrate, wherein the heating means is disposed around the reaction vessel, Driving means for controlling the heating output of the reaction vessel, temperature detecting means for detecting the temperature in the reaction vessel, gas supply means for supplying a predetermined gas into the reaction vessel, and gas exhaust means for exhausting the reaction vessel After film formation on the film formation target substrate, when removing the deposited film by introducing an etching gas into the reaction vessel, the completion of the deposited film removal is confirmed by observing the heating output of the heating means. It is characterized by doing so.
[0008]
Further, in the film forming apparatus of the present invention, the temperature in the reaction vessel is made constant when an etching gas is introduced into the reaction vessel to remove a deposited film.
Further, in the film forming apparatus of the present invention, when the etching gas is introduced into the reaction vessel to remove the deposited film, the heating output of the heating means becomes constant, thereby removing the deposited film.
Further, the deposited film removing method of the present invention is a method for removing a deposited film in a film forming apparatus for depositing a film-forming substrate in a reaction vessel and forming the film on the substrate. After film formation, a step of heating the reaction container by a heating unit, a step of supplying a predetermined etching gas into the reaction container by a gas supply unit, and a step of detecting a temperature in the reaction container by a temperature detection unit. A step of, when introducing an etching gas into the reaction vessel to remove the deposited film, confirming the completion of the deposited film removal by observing a change in the heating output of the heating means. I do.
[0010]
Further, in the deposited film removing method of the present invention, when removing the deposited film by introducing an etching gas into the reaction vessel, the output of the heating means is controlled so that the temperature in the reaction vessel becomes constant. And a step.
In the method for removing a deposited film of the present invention, when the etching gas is introduced into the reaction vessel to remove the deposited film, the completion of the removal of the deposited film is confirmed by the constant heating output of the heating means. It is characterized by doing so.
[0011]
[Action]
According to the present invention, after a predetermined film forming process is completed in this kind of film forming apparatus, an etching gas is introduced into the reaction container to remove the deposited film in the reaction container. At that time, the output value of the heater controlled so as to keep the reaction vessel at a constant temperature is focused on, and the progress of the removal of the deposited film is detected from the fluctuation of the heater output due to the generation of reaction heat in the reaction vessel.
[0012]
Specifically, when cleaning the reaction vessel of the film forming apparatus with the etching gas, the reaction vessel is first heated by the heater, and the power to be applied to the heater is controlled based on the temperature detection of the thermocouple. Thereby, the temperature inside the reaction vessel is kept constant. Next, when an etching gas that causes an etching reaction due to a thermal reaction is introduced into the reaction vessel, the deposited film deposited in the reaction vessel is etched, and reaction heat is generated at this time. Since the temperature inside the reaction vessel is controlled to be kept constant by the heater, the output of the heater itself changes.
[0013]
As the cleaning by etching progresses, the deposited film is removed at a portion where the reaction proceeds rapidly according to the gas concentration distribution or the temperature distribution in the reaction vessel, and thereafter, the reaction vessel itself starts to be etched. For this reason, a difference occurs in the reaction energy between the case where the deposited film is etched and the case where the reaction vessel is etched, and the heater output value fluctuates as the cleaning proceeds. Then, after the deposited film is completely removed, the reaction vessel itself remains as a reactant to the etching gas, so that the heater output shows a constant value. Therefore, by observing the change in the heater output value during this time, it can be confirmed whether or not the cleaning has been completely completed.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a preferred embodiment of the present invention will be described with reference to FIG.
FIG. 1 shows a schematic overall configuration example of a film forming apparatus according to the present invention. In this embodiment, the present invention is preferably applied to a hot wall type CVD apparatus, in which a silicon wafer (film formation substrate) not shown is accommodated in a reaction vessel 1 made of quartz, and a predetermined film is formed on the silicon wafer. Shall be formed.
[0015]
The film forming apparatus according to the present embodiment includes a heater 2 disposed around a reaction vessel 1, a power supply 3 for controlling the heating output of the heater 2, a heater output monitor 4 for measuring the heating output of the heater 2, A thermocouple 5 for detecting the temperature in the vessel 1, a temperature monitor 6 for measuring and displaying the temperature in the reaction vessel 1 by the thermocouple 5, a gas supply pipe 7 for supplying a predetermined etching gas into the reaction vessel 1, A dry pump 8 capable of evacuating the inside of the reaction vessel 1.
[0016]
In the above case, the heater 2 is preferably constituted by a high-frequency coil or the like. The heating output of the heater 2 is monitored by the heater output monitor 4 as the output of the power supply 3. By arranging a plurality of thermocouples 5 at respective points along the vertical direction of the reaction vessel 1 to constitute a temperature detecting means, the temperature in the reaction vessel 1 is locally and entirely measured. In the temperature monitor 6, the temperature detected by each thermocouple 5 may be monitored individually or an overall temperature based on the detected temperature (for example, an average value of the detected temperatures of the individual thermocouples 5) may be monitored. Good. The power supply 3 has a control circuit for controlling its output so as to keep the temperature inside the reaction vessel 1 constant based on the temperature inside the reaction vessel 1 detected by the thermocouple 5 inside or separately therefrom. It has a control device. In any case, the output state of the power supply 3 can be grasped by the heater output monitor 4.
[0017]
In the film forming apparatus having the above configuration, after a predetermined film forming process is completed, an etching gas is introduced into the reaction container 1 to remove a deposited film in the reaction container 1. When cleaning the reaction vessel 1 with an etching gas, the reaction vessel 1 is first heated by the heater 2. In this case, the temperature detected by the thermocouple 5 is fed back to the power supply 3 via the temperature monitor 6, whereby the power to be supplied from the power supply 3 to the heater 2 is controlled, and the temperature inside the reaction vessel 1 is kept constant. . At this time, the inside of the reaction vessel 1 is evacuated by the dry pump 8 and the output of the power supply 3 is measured by the heater output monitor 4.
[0018]
Next, an etching gas is introduced into the reaction vessel 1 from the gas supply pipe 7. At this time, the output of the power supply 3 is controlled so as to keep the temperature inside the reaction vessel 1 constant. In the reaction vessel 1, the polycrystalline silicon deposited in the reaction vessel 1 reacts with the etching gas at the set temperature at this time. In the course of this etching reaction, polycrystalline silicon is decomposed, and reaction heat is generated. The output of the power supply 3 measured by the heater output monitor 4 changes as compared to before the etching reaction (in vacuum). That is, since the heater 2 is controlled so that the temperature inside the reaction vessel 1 becomes constant, the output of the power supply 3 decreases by the amount of the reaction heat at this time.
[0019]
Further, as the cleaning with the etching gas proceeds, the polycrystalline silicon in the reaction vessel 1 is partially removed and disappears, and the reaction vessel 1 itself in that portion starts to be etched. For this reason, a difference occurs in the reaction energy between the case where the deposited film is etched and the case where the reaction vessel 1 is etched, and the heater output value fluctuates with the progress of the cleaning according to the difference in the reaction energy. After all the polycrystalline silicon has finally reacted and the deposited film has been completely removed, only the reaction vessel 1 reacts as a reactant to the etching gas, and the output of the heater 2 becomes a constant value. Is shown. By observing such a change in the heater output value on the heater output monitor 4, it is possible to reliably grasp whether or not the cleaning has been completed.
[0020]
As described above, the progress of the removal of the deposited film can be accurately grasped from the fluctuation of the output value of the heater 2 causing the etching reaction in the reaction vessel 1 without disassembling the reaction vessel 1. In this case, the cleaning, that is, the introduction of the etching is stopped at the end of the removal of the deposited film, thereby preventing the reaction vessel 1 from being unnecessarily consumed.
[0021]
【The invention's effect】
As described above, according to the present invention, when an etching gas is introduced into a reaction vessel to remove a deposited film in this type of film forming apparatus, an output value of a heater for causing an etching reaction is monitored, The progress of the removal of the deposited film can be accurately grasped from the fluctuation of the heater output. In the conventional apparatus, it has been difficult to confirm the completion of the cleaning, so that there have been problems such as prolonged downtime of the apparatus or exhaustion of the quartz reaction tube. In addition, removal of the deposited film can be confirmed accurately. As a result, there are advantages that the operation rate can be improved and the consumption of parts can be remarkably suppressed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a schematic overall configuration of a film forming apparatus according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reaction vessel 2 Heater 3 Power supply 4 Heater output monitor 5 Thermocouple 6 Temperature monitor 7 Gas supply pipe 8 Dry pump

Claims (6)

A film formation apparatus for housing a film formation substrate in a reaction vessel and forming a film on the substrate,
Heating means disposed around the reaction vessel, driving means for controlling the heating output of the heating means, temperature detection means for detecting the temperature in the reaction vessel, and supplying a predetermined gas into the reaction vessel Gas supply means, and gas exhaust means for exhausting the reaction vessel,
After removing the deposited film by introducing an etching gas into the reaction vessel after the deposition on the deposition target substrate, the completion of the deposited film removal is confirmed by observing the heating output of the heating unit. A film forming apparatus characterized by the above-mentioned. The film forming apparatus according to claim 1,
A film forming apparatus, wherein the temperature in the reaction vessel is kept constant when removing the deposited film by introducing an etching gas into the reaction vessel. The film forming apparatus according to claim 2,
A film forming apparatus, wherein when the etching gas is introduced into the reaction vessel to remove the deposited film, the completion of the removal of the deposited film is confirmed by the constant heating output of the heating means. . A method for removing a deposited film in a film forming apparatus that accommodates a film formation substrate in a reaction vessel and forms a film on the substrate,
After film formation on the film formation substrate, heating the reaction vessel by heating means,
Supplying a predetermined etching gas into the reaction container by gas supply means,
Detecting the temperature in the reaction vessel by temperature detecting means,
Confirming the completion of the deposition film removal by observing a change in the heating output of the heating means when removing the deposition film by introducing an etching gas into the reaction vessel. A method for removing a deposited film in a film forming apparatus. The method for removing a deposited film according to claim 4,
Controlling the output of the heating means so that the temperature in the reaction vessel becomes constant when introducing the etching gas into the reaction vessel to remove the deposited film. A method for removing a deposited film in a film forming apparatus. The method for removing a deposited film according to claim 5,
When removing the deposited film by introducing an etching gas into the reaction vessel, the heating output of the heating means is made constant to confirm the completion of the deposited film removal. Method.

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