JP2892980B2 - Dry process treatment method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a dry processing method for a dry etching apparatus or the like. 2. Description of the Related Art Conventionally, a pressure control mechanism of a dry processing apparatus is configured as shown in FIG. That is, the pressure control mechanism is configured to keep both the flow rate of the processing gas and the pressure of the processing chamber constant. The gas flow control unit 2 for keeping the gas flow constant comprises a gas source 9, an opening / closing valve 8, a gas flow sensor 5, a control valve 3, a control valve driving unit 4, a servo amplifier 6, and a flow setting unit 7. I have. The gas flow rate is detected by the flow rate sensor 5, and the difference between the flow rate and the value set by the flow rate setting section 7 is amplified by the servo amplifier 6 and the control valve 3 is controlled via the control valve driving section 4.
Is moved to maintain a constant gas flow rate. The pressure control section 10 of the processing chamber 1 comprises a pressure sensor 11, an exhaust conductance control valve 12, a valve driving section 13, a servo amplifier 14, a pressure setting section 15, and a vacuum exhaust device 16. In controlling the pressure, the pressure in the processing chamber 1 is detected by the pressure sensor 11, and the difference from the value set in the pressure setting unit 15 is amplified by the servo amplifier 14.
The exhaust capacity of the exhaust device 16 is changed by changing the conductance of the control valve 12 via the control valve 12. In the exhaust control section 10, when the control valve 12 is changed, the pressure gradually changes due to the relationship between the volume of the processing chamber 1, the amount of gas flowing in, and the amount of exhaust. Therefore, if the valve is opened and closed according to the difference between the measured pressure and the set pressure, the pressure control system vibrates, and the pressure cannot be controlled stably. Therefore, the response of the servo amplifier 14 is delayed so that the pressure can be controlled stably. [0007] In the dry process apparatus, in order to perform the process with good reproducibility, it is necessary to perform the process under a constant process condition, that is, a constant gas flow rate and gas pressure. However, in the conventional pressure control method, it takes time until the pressure becomes constant, which has been a bottleneck in improving the processing capability of the dry process apparatus. In particular, in the conventional pressure control method, it takes about one minute to reach the set pressure, and the ratio to the entire processing time also increases with the speeding up of the dry process.
20% to 30% of the time. Therefore, shortening the gas pressure control time has become indispensable for improving the processing capacity. An object of the present invention is to provide a dry process processing method capable of improving the control response of the dry process pressure and improving the processing capability. [0011] In order to achieve the above object, the present invention provides a dry processing method for processing a sample in a processing chamber maintained at a predetermined pressure by introducing a gas from the outside. By fully opening the exhaust valve of the processing chamber in which the sample is placed, the interior of the processing chamber is evacuated to a high vacuum, and then closing the exhaust valve of the processing chamber and introducing gas into the processing chamber. The dry process is performed by controlling the opening degree of the exhaust valve based on the pressure inside the processing chamber in a state where the gas is introduced and the pressure inside the processing chamber falls within a predetermined pressure range. Further, the present invention provides a dry process processing method for processing a sample in a processing chamber maintained at a predetermined pressure by introducing a gas from the outside, by fully opening an exhaust valve of a processing chamber in which a sample is disposed. The inside of the processing chamber is evacuated to a high vacuum, then the exhaust valve of the processing chamber is closed, and gas is introduced into the processing chamber at a larger flow rate than when the sample is dry-processed in the processing chamber. Then, in a state where the pressure inside the processing chamber is within a predetermined pressure range, the opening degree of the exhaust valve and the flow rate of the gas are controlled based on the pressure inside the processing chamber to perform the dry process. FIG. 2 shows an embodiment according to the present invention, which will be described below. The processing chamber 20 for performing the dry process processing is provided with a gas supply pipe 22 for supplying a processing gas and an exhaust pipe 32 for exhausting the processing chamber. The gas supply unit includes a gas source 31, an on-off valve 3,
0, a flow sensor 27, and a control valve 23. The signal from the flow sensor 27 is supplied to an A / D converter 28
Through the microcomputer 21. The control valve 23 is moved by a drive motor 24,
An encoder 25 is connected to the motor, and a signal from the encoder 25 is sent to the microcomputer 21. The drive motor 24 is connected to the microcomputer 2
It is moved by the driver 26 controlled to 1. To set the gas flow rate, a setting signal is sent from the flow rate setting section 29 to the microcomputer 21. The exhaust section comprises a control valve 33 for conductance and a vacuum exhaust device 40. The control valve 33 has a drive motor 34
The encoder 35 is connected to the motor, and its signal is sent to the microcomputer 21. The drive motor 34 is connected to the microcomputer 2
It is moved by the driver 36 controlled to 1. The signal from the pressure sensor 37 attached to the processing chamber 20 is sent to the microcomputer 2 via an A / D converter 38.
Sent to 1. The gas pressure is set by sending a setting signal from the pressure setting unit 39 to the microcomputer 21. The operation of each part during the pressure control in the above configuration will be described below. The processing chamber 20 exhausts the processing chamber to a low pressure by fully opening the control valve 33. A workpiece (not shown) is carried into the processing chamber 20 by a transport system (not shown). When the completion of loading is detected, the pressure control valve 33 is closed and the gas flow control valve 23 for gas supply is fully opened as shown in FIG. When the processing gas is a gas obtained by mixing two or more types of raw material gases, the mixing ratio of each raw material gas to be supplied does not change, and one of the mixed gases is set to the maximum supply amount of the control valve of the gas supply unit. The control is performed by the microcomputer 21 as shown in FIG. At this time, the pressure approaches the set pressure in a few seconds, though it varies depending on the processing conditions. In the microcomputer 21, the rotation angles of the valve drive motors 24 and 34 corresponding to the set conditions at the time of the previous processing are stored in the memory by the signals from the encoders 25 and 35. The pressure in the processing chamber is checked by the pressure sensor 37, and when the pressure falls within a range of ± 20% of the set pressure, the driver 2 is instructed by the microcomputer 21.
The pressure and the open / close ratio of the gas flow control valve are fixed to the state stored in the memory via the ports 6 and 36. Further, the pressure in the processing chamber is set to ± 10 of the set pressure.
%, Control of the control valves 23 and 33 is performed by a conventional method of controlling according to a set pressure and a pressure difference in the processing chamber. Next, when the processing chamber enters a pressure of ± 3% of the set pressure for 1 minute, the opening / closing ratio of the control valve is read from the encoders 25 and 35, the memory storing the valve opening / closing ratio in the microcomputer is cleared, and new data is stored. Write. As described above, in the pressure control method according to the present invention, since the inflow gas amount is first maximized and the exhaust valve is closed, the pressure rises again in a short time, and when the pressure approaches the set pressure, the opening / closing ratio of the valve valve is increased. Since the pressure is maintained at the set pressure, there is no problem that the pressure overshoots and vibrates as in the conventional method. In this embodiment described above, the set pressure can be reached in about 10 seconds, and the time can be reduced to about 1/6 of the conventional one. In this embodiment, the pressure control method up to the start of the processing has been described. However, the same can be applied to the case where the processing conditions such as the gas flow rate, the gas line, and the gas pressure are changed in the middle. Even in that case, the control valve opening / closing ratio under the processing conditions after the halfway change is stored,
If the pressure condition after the change is high, perform the method described in the present embodiment.If the pressure condition after the change is low, on the contrary, stop the gas supply, open the exhaust valve fully, and similarly approach the set pressure. it can. In this embodiment, an example in which pressure control is performed by opening and closing a control valve has been described.
It is apparent that basically the same method can be used as long as the exhaust method can change the exhaust amount. For example, evacuating with a mechanical vacuum pump,
When controlling the pressure by changing the exhaust amount according to the number of revolutions of the vacuum pump, the number of revolutions under each processing condition can be stored and controlled. As described above, according to the present invention,
Since the time from supplying the processing object into the processing chamber to setting the processing chamber to a predetermined pressure for processing can be shortened as compared with a method using a conventional apparatus, a dry process apparatus is used. Can improve the processing capacity of
The effect is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a pressure control system in a conventional dry process device. FIG. 2 is a diagram showing one embodiment of a pressure control system in the dry process device of the present invention. FIG. 3 is a diagram showing a pressure control flow in the dry process device of the present invention. [Description of Signs] 20 processing chamber, 21 microcomputer, 23 control valve, 25 encoder, 27 flow rate sensor, 33 control valve, 35 encoder, 37 pressure sensor, 40 vacuum exhaust device.

Continuation of front page    (72) Inventor Teru Fujii               292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa               Hitachi, Ltd. Production Technology Laboratory (72) Inventor Takashi Uemura               292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa               Hitachi, Ltd. Production Technology Laboratory (72) Inventor Susumu Aiuchi               292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa               Hitachi, Ltd. Production Technology Laboratory                (56) References JP-A-58-140127 (JP, A)                 JP-A-57-174465 (JP, A)                 JP-A-58-115812 (JP, A)                 JP-A-58-9320 (JP, A)                 Takuo Sugano "Semiconductor Plasma Processing Technology               Syutsu ”(Showa 55-7-10) Sangyo Tosho p.               183-189

Claims (1)

(57) [Claims] A dry processing method for processing a sample in a processing chamber maintained at a predetermined pressure by introducing a gas from the outside, wherein the exhaust valve of the processing chamber in which the sample is disposed is fully opened. The inside of the processing chamber is evacuated to a high vacuum, and then the exhaust valve of the processing chamber is closed and the gas is introduced into the processing chamber. Wherein the opening degree of the exhaust valve is controlled based on the pressure inside the processing chamber in a state where the pressure falls within the range of the pressure. 2. A dry processing method for processing a sample in a processing chamber maintained at a predetermined pressure by introducing a gas from the outside, wherein the exhaust valve of the processing chamber in which the sample is disposed is fully opened. The inside of the processing chamber is evacuated to a high vacuum, and then the exhaust valve of the processing chamber is closed and the gas is introduced into the processing chamber at a larger flow rate than when the sample is dry-processed in the processing chamber. And
The opening degree of the exhaust valve and the flow rate of the gas are controlled based on the pressure inside the processing chamber in a state where the gas is introduced and the pressure inside the processing chamber is within a predetermined pressure range. A dry process treatment method.