JP3197969B2 - Semiconductor substrate processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a semiconductor substrate which does not cause particles or impurities to adhere to an object to be processed such as a wafer in the processing of the semiconductor substrate .

[0002]

2. Description of the Related Art FIG. 4 is a diagram for explaining an example of a conventional method. In the conventional method, when an object to be processed is processed under reduced pressure in the processing chamber, after the object to be processed is carried into the processing chamber under the supply of the replacement gas, the pressure of the processing chamber is reduced to 76 as shown in FIG.
In 0 Torr (atmospheric pressure), the exhaust without supplying the replacement gas t ₁
Start point, evacuating to a pressure reached P _1. Thereafter, replacement gas t ₂ point, begins to conduct such process gas begins processing an object to be processed, and performs processing such as CVD film produced in the desired pressure P _2.

[0003]

However, in the above-mentioned conventional method, the replacement gas or the like starts flowing at time t ₂ ,
At the beginning of this gas flow, the gas enters the processing chamber,
When the gas flow rate and the pressure suddenly change as indicated by Qa and Pa, there is a problem that particles and impurities adhering to the chamber wall of the processing chamber are wound up and adhere to the surface of the processing object.

[0004]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method for processing an object to be processed under reduced pressure in a processing chamber.
In the method, the pressure in the processing chamber in which the
Exhaust gas with a vacuum pump when replacing gas to atmospheric pressure
The method is characterized in that the gas is returned to the atmospheric pressure while the replacement gas is flowed .

[0005] As described above, when the object to be processed is processed under reduced pressure in the processing chamber or when the processing chamber is returned to the atmospheric pressure, the gas after vacuum evacuation, which is a problem of the prior art, is performed by flowing the replacement gas. Therefore, it is possible to prevent the particles and impurities generated at the beginning of the flow from being rolled up, and it is possible to greatly reduce the amount of particles and impurities adhering to the object to be processed.

[0006]

FIG. 1 is a diagram for explaining the configuration of an embodiment of the method of the present invention . First, the configuration of the present embodiment will be described.
In FIG. 1, reference numeral 1 denotes a processing chamber for processing an object to be processed under reduced pressure;
Reference numerals 2 and 3 denote replacement gas supply pipes and processing gas supply pipes connected to the supply ports of the processing chamber 1, respectively. Reference numerals 4 and 5 denote replacement gas supply valves inserted into the gas supply pipes 2 and 3, respectively. The processing gas supply valves 9 and 10 are flow controllers inserted in series with the gas supply valves 4 and 5, respectively.
Reference numeral 8 denotes an exhaust pipe connected to the exhaust port of the processing chamber 1,
Auxiliary exhaust valves 6 and 7 are connected and inserted in parallel. Reference numeral 11 denotes a vacuum pump connected to the exhaust pipe 8.

Next, the operation of this embodiment in the above configuration will be described. FIG. 2 shows a gas replacement sequence 1 according to the present invention.
FIG. 3 is an explanatory diagram showing an example, and FIG. 3 is an explanatory diagram showing one example of a film forming sequence. As shown in FIG. 3, the replacement gas supply valve 4 is opened in the processing chamber 1 to flow the replacement gas, and the workpiece is loaded into the processing chamber 1 in this state. After a while
As shown in FIGS. 2 and 3, the auxiliary exhaust valve 7 is opened while the replacement gas is flowing, and the exhaust is performed by the vacuum pump 11 to t _1.
At this point, the pressure in the processing chamber 1 is reduced from 760 Torr (atmospheric pressure).

When the pressure in the processing chamber 1 reaches a predetermined pressure at time t ₁₂ , the main exhaust valve 6 is opened, and exhaust is performed until the pressure reaches the ultimate pressure P ₁ . Thereafter, as shown in FIG. 3, at time t ₂ , the processing gas supply valve 5 is opened, and the processing gas is started to flow into the processing chamber 1. _Then , a film is formed on the object to be processed. In the conventional method, as shown in FIG. 4, the replacement gas and the processing gas are started to flow at the film formation start time t ₂ , and the gas does not flow until then, so that the gas enters the processing chamber 1 at the beginning of the gas flow. gas flow rate and pressure Qa, suddenly changes as indicated by Pa Te, but since in the present invention are flowed replacement gas into the film forming start time t ₂ before the gas to flow beginning of the processing gas processing chamber 1 And the gas flow rate and pressure change slowly and suddenly as shown by Qc and Pc, so that particles and impurities adhering to the chamber wall of the processing chamber 1 are hardly rolled up, and The amount of these adhering to the processed material can be greatly reduced.

For example, a large amount of hydrogen gas is used as a replacement gas in an epitaxial growth apparatus or the like, and Si is used as a processing gas.
When H ₄ (monosilane) gas is used, a large amount of silicon polymer adheres to the chamber wall of the processing chamber (reaction chamber).
In the case of the present invention, it is particularly effective in a decompression process, and conventionally,
The number of hundreds adhered to one processing object can be significantly reduced to several. In addition, since a particle generation source of a mechanical mechanism, for example, a semiconductor substrate transfer mechanism exists in a load lock chamber or the like of a semiconductor substrate cassette, the present invention is also applicable to a case where such a vacuum vessel is replaced with a vacuum inert gas. It is suitable, and it is possible to reduce the number of dozens that have conventionally adhered to one processing object to several.

When the inside of the processing chamber 1 is gas-replaced in order to take out the processed object from the processing chamber, the processing gas supply valve 5 is closed and then the main exhaust valve 6 as shown in FIG.
Is closed at time t ₃ , and then at time t ₄ , the auxiliary exhaust valve 7 is closed.
Is closed, and during that time, the pressure is reduced and exhausted while flowing the replacement gas to return to the atmospheric pressure. In this embodiment, as can be seen from FIG. 2, the flow controllers 9, 1 are designed so that the total gas amount of the replacement gas and the processing gas is always constant.
Controlled by 0. The method and apparatus of the present invention can of course be applied to processing chambers such as a reduced-pressure CVD apparatus, an epitaxial growth apparatus, a diffusion apparatus, and a heat treatment apparatus.

[0011]

As described above, according to the present invention, the processing chamber
Treating the workpiece under reduced pressure with
Gas in the processing chamber where
When replacing, replace gas while exhausting with a vacuum pump.
Since the gas is flowed back to the atmospheric pressure, the amount of particles and impurities adhering to the chamber wall of the processing chamber is wound up by flowing the replacement gas, greatly reducing the amount of particles and impurities adhering to the processing object. Can be.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a configuration of an embodiment of a method of the present invention .

FIG. 2 is an explanatory diagram showing an example of a gas replacement sequence according to the present invention.

FIG. 3 is an explanatory diagram showing one example of a film forming sequence.

FIG. 4 is a diagram illustrating an example of a conventional method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 processing chamber 2 replacement gas supply pipe 3 processing gas supply pipe 4 replacement gas supply valve 5 processing gas supply valve 6 main exhaust valve 7 auxiliary exhaust valve 8 exhaust pipe 9 flow controller 10 flow controller 11 vacuum pump

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-285924 (JP, A) JP-A-1-246824 (JP, A) JP-A-62-143419 (JP, A) JP-A 64-64 59912 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/205 H01L 21/22 H01L 21/31 H01L 21/324

Claims (1)

(57) [Claims] 1. A method for processing an object to be processed under reduced pressure in a processing chamber, wherein the processing chamber in which the object to be processed is installed is changed from a reduced pressure state to an atmospheric pressure state.
When replacing with gas, replace while exhausting with a vacuum pump.
A method for treating a semiconductor substrate , comprising flowing a working gas to return to atmospheric pressure.