JP2003332246A - Sensor protective mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for preventing a product, which is generated by reactive gas, from being accumulated on a sensor used in a process such as a semiconductor manufacturing process of applying reaction product gas, and preventing a contact made by a detection part of the sensor with the reactive gas from causing corrosion. <P>SOLUTION: For the sensor for measuring a pressure and so on of a vacuum system device and equipment for applying reactive gas, a passage is provided between the sensor and a space chamber filled with the reactive gas, and a means for applying inert gas through the passage. A flow channel is formed which connects the sensor and the space chamber filled with reactive gas and inert gas is applied through the flow channel to generate a flow of the inert gas from the sensor to the space chamber filled with the reactive gas, so that it is possible to prevent the reactive gas from flowing into the sensor. Thus, it is possible to prevent the detection part of the sensor from making contact with the reactive gas and causing corrosion and prevent the product, which is generated by the reactive gas, from adhering to the detection part of the sensor. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to the accumulation of products of a reactive gas in a sensor used in a process of flowing a reaction product gas such as a semiconductor manufacturing process, and the detection of a sensor. The present invention relates to a sensor protection mechanism for preventing a portion from being corroded by contact with a reaction gas. [0002] A typical example of a semiconductor surface treatment method is a plasma CVD method. The plasma CVD method is a general method for manufacturing an amorphous semiconductor thin film or a microcrystalline semiconductor thin film. In this plasma CVD method, a reactive gas is introduced into a chamber and exhausted from the chamber by an exhaust pump at the same time. [0003] In recent years, various sensors have been attached to a semiconductor manufacturing apparatus for flowing gas as described above. For example, there are sensors for measuring the pressure in a chamber, measuring the flow rate of a reactive gas, and measuring the pressure of a vacuum pump attached to a semiconductor manufacturing apparatus for exhausting the gas in the chamber. These sensors are used for various control of the device and play an important role. As the pressure sensor used for the purpose of contacting with the reactive gas, an expensive material having high corrosion resistance is used as a material, and the pressure is measured such that the detecting portion of the sensor is in direct contact with the reactive gas. Was. [0005] However, in the case of an apparatus for flowing a reactive gas such as the above-mentioned semiconductor manufacturing apparatus, as shown in FIG. Since the sensor is arranged at a position where the detection unit 302 of the sensor for the reaction product gas and the pressure or the like is in direct contact, products made of the reactive gas are deposited on the detection unit, and accurate detection cannot be performed. There was something. Further, in order to prevent the sensor from being damaged and becoming inoperable due to corrosion by the reactive gas, an extremely expensive material having high corrosion resistance must be used, and the cost for the sensor part is reduced. There was such a problem. SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a method for measuring a pressure or the like of a vacuum gauge for flowing a reactive gas and a sensor filled with the reactive gas. A passage is provided between the space chambers, and a means for flowing an inert gas into the passage is provided. In this manner, a flow passage is formed between the sensor and the space chamber filled with the reactive gas, and an inlet for injecting an inert gas into the flow passage is provided. By creating a flow of the inert gas into the filled space, the reactive gas can be prevented from flowing to the sensor side, so that deposits generated by the reactive gas do not adhere to the sensor part. it can. Even if the reactive gas slightly enters the pressure sensor side, the concentration of the reactive gas can be diluted by the inert gas, and deposits are hardly formed. An embodiment of a pressure sensor according to the present invention will be described below with reference to FIG. This embodiment shows a case where the present invention is applied to a pressure sensor for measuring a pressure in a space 101 such as a chamber of a semiconductor manufacturing apparatus filled with a reactive gas. The reactive gas is injected into the space 101 from the inlet 102 and is discharged out of the space 101 from the outlet 103 connected to a vacuum pump or the like (not shown).
The sensor protection mechanism 104 and the pressure sensor 105 of the present invention are attached to the wall of the space room. The sensor protection mechanism includes a relatively narrow passage 106 connecting the space chamber 101 and the pressure sensor 105, and an injection passage 107 for flowing an inert gas through the passage 106. By flowing a small amount of inert gas through the injection path 107, the pressure sensor 10
The inert gas flows from the 5 side to the space 101 side,
The reactive gas in the space chamber 101 can be prevented from flowing into the passage 106, and the pressure sensor can be protected from failure due to adhesion of a product caused by the inert gas or corrosion of the detection unit. Therefore, even if an expensive material pressure sensor is not used so that the detection portion of the sensor is not corroded by contact with the reactive gas, the detection portion of the pressure sensor can be prevented from contacting the reactive gas by the technique of the present invention without using a pressure sensor of an expensive material. Therefore, an inexpensive pressure sensor can be used. Next, an example in which the sensor protection device of the present invention is applied to a screw type vacuum pump will be described with reference to FIG. First, the configuration of the screw vacuum pump 200 according to the present embodiment will be described. The screw type vacuum pump 200 has screw rotors 201 and 202. The screw rotors 201 and 202 are provided in a housing 203 as an exhaust-side rotor storage chamber formed inside the housing 203.
It is stored in. In detail, the screw rotor 20
1 is rotatably supported by the housing 203 by bearings 204 and 205, and the screw rotor 202 is
The housing 203 is rotatably supported by 06 and 207. Also, seals 208, 209, 210
And 211 isolate the bearings 204, 205, 206 and 207 from the exhaust chamber 210 e in the housing 203, prevent the lubricant of the bearings 204, 205, 206 and 207 from leaking into the housing 203, and From the exhaust chamber 210e of the bearings 204, 205,
It is possible to prevent a reactive gas or a product of the reactive gas from entering the 206 and 207. One end of each of the screw rotor 201 and the screw rotor 202 has a screw rotor 20.
Timing gears 212 and 213 for rotating the other of the screw rotor 201 and the screw rotor 202 with the rotation of one of the screw rotor 202 and the screw rotor 202 are fixed so as to mesh with each other. Further, a motor 214 is integrally connected to one end of the screw rotor 202. A gear chamber 215 in which the timing gears 212 and 213 are stored has a lubricating oil 216 stored at the bottom. The gear chamber 215 and the motor 214 are sealed by oil seals 217 and 218 so that the lubricating oil 216 in the gear chamber 215 does not leak to the motor side. In this embodiment, a pressure sensor 219 for dealing with a case in which deposits generated from a reactive gas are deposited on the exhaust port 224 and completely block the exhaust port 224 is taken as an example. When the exhaust port 224 is clogged, the pressure after the exhaust port 224 increases, and this is detected by the pressure sensor 219, and the vacuum pump is stopped. Therefore, it is necessary to operate the pressure sensor 219 stably for a long period of time.
The exhaust processing device 22 in the exhaust path 223 connected to
The sensor protection mechanism of the present invention was applied to a portion close to 1 (a portion easily clogged). A relatively narrow passage 220 connecting the exhaust passage 223 and the pressure sensor 219 and the passage 22
By providing an injection path 222 for flowing an inert gas at 0 and flowing a small amount of inert gas, an inert gas can flow from the pressure sensor 219 side to the exhaust path 223 side. It is possible to prevent the volatile gas from flowing into the passage 220, and to protect the pressure sensor 219 from failure due to adhesion of a product caused by the inert gas or corrosion of the detection unit. Also, the sensor 219 is
By arranging it at right angles to the direction in which the inert gas flows, it is possible to reduce the influence of dynamic pressure. The present invention is applicable not only to the vertical screw type vacuum pump in the above embodiment, but also to all vacuum pumps such as a horizontal type screw vacuum pump, a roots type vacuum pump and a claw type vacuum pump. Needless to say, this is possible. As described above, a passage is provided between a sensor for measuring the pressure or the like of a vacuum system or equipment for flowing a reactive gas and a space chamber filled with the reactive gas. By providing a means for flowing the inert gas into the passage, a flow passage is formed between the sensor and the space chamber filled with the reactive gas, and a note for injecting the inert gas into the flow passage. An inlet is provided to create a flow of the inert gas from the sensor side to the space filled with the reactive gas, thereby preventing the reactive gas from flowing into the sensor side. Therefore, it is possible to prevent the sensor portion from being corroded by the reactive gas and from deposits generated by the reactive gas.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment in which the sensor protection mechanism of the present invention is applied by a pressure sensor. FIG. 2 is an embodiment in which the sensor protection mechanism of the present invention is applied to a pressure sensor of a vacuum pump. FIG. 3 shows an example in which measurement is performed with a conventional pressure sensor. DESCRIPTION OF SYMBOLS 101 Space chamber 102 Inlet 103 Outlet 104 Sensor protection mechanism 105, 219 Pressure sensor 106, 220 Passage 107 Injection paths 201, 202 for flowing inert gas Screw rotor 203 Housings 204, 205, 206, 207 Bearing 208, 209, 210, 211 seal 210e Exhaust chamber 212, 213 Timing gear 214 Motor 224 Exhaust port 221 Exhaust processing device 223 Exhaust path

Claims (1)

Claims: 1. A passage is provided between a sensor for measuring a pressure or the like of a vacuum system / equipment for flowing a reactive gas and a space chamber filled with the reactive gas, A sensor protection mechanism provided with means for flowing an inert gas into the passage.