Vacuum exhaust system and cleaning method

Abstract

The invention provides a vacuum exhaust system capable of reducing the consumption of CIF-based gas used for cleaning and shortening the cleaning time. A heater (400) is provided in an exhaust pipe (18) from a dry pump (100) to a deinsectization device (19) to heat the exhaust pipe (18), and the temperature of the exhaust pipe (18) is set to a temperature exceeding 180 DEG C. In the exhaust piping (18), both the piping and a gasket as a sealing member are made of metal. In addition, CIF3 gas for cleaning is introduced. The CIF3 gas is activated when the temperature exceeds 180 DEG C, and the cleaning efficiency is remarkably improved. On the other hand, the gasket made of metal is used, so that even if the CIF3 gas is activated, the sealing performance is not easy to generate problems. Therefore, it is not necessary to wait until the exhaust pipe (18) becomes 180 DEG C or less, and the cleaning time can be shortened.

Description

Technical Field

[0001] The invention relates to a vacuum exhaust system and a cleaning method in a semiconductor manufacturing device. Background Art

[0002] Generally speaking, in the semiconductor manufacturing process, semiconductors or insulators, metal films, etc. are deposited on semiconductor wafers, and CVD (Chemical Vapor Deposition) or dry etching treatment using chemical vapor reaction to form a film is performed. In the process chamber, various gases such as silane (SiH4) (4 is a subscript, but in order to prevent erroneous conversion of the text code, the subscripts and subscripts are represented by ordinary characters below) gas are used. In addition, the used gas (exhaust) discharged from the process chamber is sucked by a dry pump, etc., and then introduced into a harm removal device through a gas exhaust pipe, and a harm removal treatment is performed in the harm removal device.

[0003] In such semiconductor manufacturing processes, if the used gas is cooled, it will solidify as a film or powder and adhere to the exhaust pipes outside the process chamber, the dry pump, and the decontamination device, and the accumulation will cause pipe clogging. Therefore, frequent maintenance is required.

[0004] In particular, in the pipe on the exhaust side of the dry pump, the exhaust gas is pressurized to near atmospheric pressure and flows therethrough, so the accumulation of reaction products (hereinafter referred to as products) due to gas components contained in the exhaust gas in the pipe becomes significant.

[0005] Therefore, in order to prevent the accumulation of products and remove the accumulated products, gas is used to clean the pipes. As the gas used, as described in Patent Document 1 and Patent Document 2, ClF-based gases can be cited, for example, ClF3 (chlorine trifluoride) can be cited.

[0006] However, the exhaust piping of conventional dry pumps uses an elastic gasket (a fixed sealing component for maintaining airtightness of the structure), so the cleaning gas must be flowed after the temperature of the piping reaches 180°C or below. This is because ClF-based gases are significantly activated at 180°C or above, and there is a possibility that the elastic gasket will be damaged. In particular, ClF3 gas is highly toxic, and preventing damage to the sealing material is extremely important in terms of safety.

[0007] It is known that if the ClF 3 gas is pure, it is stable up to 180° C. in a glass container, but if the temperature reaches above this, it decomposes due to a free radical mechanism.

[0008] Therefore, the cleaning work has to wait until the temperature of the high-temperature pipes reaches 180° C. or less, which takes extra time. In particular, since the pipes are provided with heat insulating materials, cooling due to heat dissipation takes time.

[0009] Furthermore, when the temperature of the pipe becomes 180° C. or lower, the activity of the ClF-based gas decreases and the reactivity with the product decreases, so a larger amount of gas must be used.

[0010] Patent document 1: Japanese Patent Application Laid-Open No. 2-77579.

[0011] Patent document 2: Japanese Patent No. 2776700.

[0012] Patent document 3: Japanese Patent No. 3047248.

[0013] The invention described in Patent Document 1 relates to a cleaning (washing) method for removing reaction products adhering to a reaction container using ClF3 gas in a deposited film forming apparatus for forming a deposited film.

[0014] The invention described in Patent Document 2 relates to a cleaning method for the following compound, characterized in that a compound containing generated ammonium silicofluoride as a main component is brought into contact with ClF3 gas or F2 gas for reaction.

[0015] The invention described in Patent Document 3 relates to a cleaning method, characterized in that, while maintaining the processing temperature in the processing container at 450°C or above, a cleaning gas containing diluted ClF3 is supplied into the processing container and the polysilicon film attached to the processing container is removed. In addition, in the column (Problems to be Solved by the Invention), it is recorded that "it has been reported that cleaning can be performed even without setting it to a plasma state, especially when ClF3 is used. However, ClF3 is highly reactive, so it is not considered to be used above 400°C, and cleaning is usually performed below 400°C. Therefore, in the process of forming a film at above 400°C, especially above 600°C, the temperature in the device has to be lowered to below 400°C in order to perform ClF3 cleaning, resulting in long-term cleaning."

[0016] However, the exhaust piping of the above-mentioned processing container (especially from the dry pump to the harm removal device) needs to have improved conductivity from the perspective of exhaust efficiency, and the diameter has to be enlarged. The corresponding metal (metal) gasket is difficult to develop and manufacture, so it is basically not supplied to the market within the known range.

[0017] In addition, there is a significant tendency for metal gaskets that are compatible with flanges that are not in the shape of ultra-high vacuum flanges (ConFlat Flange) but are in the general ISO standard or KF standard (NW standard) and can be reused.

[0018] In recent years, metal (metal) gaskets have been developed that can be used for pipes with flanges of general ISO standards or KF standards (NW standards) as described above. Therefore, by using such metal gaskets, even if the temperature of the exhaust pipe with the flange exceeds 180°C, sufficient sealing properties can be maintained. Therefore, ClF-based gas such as ClF3 can be activated and used, and its consumption can be reduced, shortening the cleaning time. Summary of the invention

[0019] Therefore, an object of the present invention is to provide a vacuum exhaust system and a cleaning method capable of reducing the consumption of ClF-based gas and shortening the cleaning time by heating the exhaust pipe to a temperature exceeding 180°C.

[0020] In the invention described in technical solution 1, a vacuum exhaust system is provided, the vacuum exhaust system includes an exhaust pipe connected to a semiconductor manufacturing device and exhausting air to a harm removal device via a vacuum pump. The vacuum exhaust system is characterized in that a sealing component used in the exhaust pipe is made of metal, and a heating mechanism for heating the exhaust pipe is provided at a portion of the exhaust pipe from the vacuum pump to the harm removal device. When a cleaning gas containing a ClF-based gas or a NF-based gas is introduced, the temperature of the exhaust pipe is heated to a temperature exceeding 180°C by the heating mechanism.

[0021] In the invention described in claim 2, there is provided the vacuum exhaust system described in claim 1, characterized in that the sealing member is made of a metal material having high corrosion resistance to the clean gas.

[0022] In the invention described in claim 3, there is provided a vacuum exhaust system described in claim 1 or 2, characterized in that the exhaust pipe is made of a metal material having high corrosion resistance to the clean gas.

[0023] In the invention described in technical solution 4, a cleaning method is provided, in which, in a vacuum exhaust system including an exhaust pipe connected to a semiconductor manufacturing device and exhausting air to a harm removal device via a vacuum pump, the product attached to the exhaust pipe is removed by a cleaning gas including a ClF-based gas or a NF-based gas, and the cleaning method is characterized in that when the cleaning gas is introduced, the temperature of the portion of the exhaust pipe from the vacuum pump to the harm removal device is heated to a temperature exceeding 180°C.

[0024] Effects of the Invention

[0025] According to the vacuum exhaust system of the present invention, the exhaust pipe and the sealing member used in the exhaust pipe are made of metal, and ClF-based gas or NF-based gas can be used at high temperature, so the consumption can be reduced and the cleaning time can be shortened.

[0026] According to the cleaning method of the present invention, cooling time of the exhaust pipe is not required, so the cleaning time can be shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a block diagram showing a schematic overall configuration of an exhaust gas treatment device in a semiconductor manufacturing process of a vacuum exhaust system in a semiconductor manufacturing apparatus according to an embodiment of the present invention.

[0028] Figure 2 It is a schematic side cross-sectional view schematically showing the internal structure of the dry pump according to the present embodiment.

[0029] Figure 3 This is a diagram for explaining the introduction of a cleaning gas into a vacuum exhaust system in the semiconductor manufacturing apparatus according to the present embodiment. DETAILED DESCRIPTION

[0030] Below, refer to Figures 1 to 3 , the preferred embodiments of the present invention are described in detail.

[0031] (1) Overview of Implementation

[0032] exist Figure 3 In the embodiment, a heater 400 (heating means) is provided in the exhaust pipe 18 from the dry pump 100 to the detoxification device 19 to heat the exhaust pipe 18. The temperature of the exhaust pipe 18 is set to a temperature exceeding 180° C., for example, 300° C. The exhaust pipe 18 is made of metal, and the gasket as a sealing member.

[0033] Furthermore, in order to perform cleaning for removing the product, ClF3 gas is introduced from the process chamber. The ClF3 gas is activated when the temperature exceeds 180°C, and the cleaning efficiency is significantly increased. On the other hand, since the exhaust pipe 18 uses a metal gasket, it is not easy to cause problems in terms of sealing performance even if the ClF3 gas is activated.

[0034] Therefore, there is no need to wait until the exhaust pipe 18 reaches 180° C. or lower, and the time required for cleaning can be shortened. In addition, since activated ClF 3 gas can be used, safety can be ensured and the amount used can be reduced.

[0035] In addition, the present embodiment also includes a case where the exhaust pipe 18 is heated to a temperature exceeding 180° C., for example, 300° C. before cleaning, and is continuously heated and maintained at this temperature during cleaning.

[0036] (2) Details of implementation methods

[0037] Figure 1 This is a block diagram showing a schematic overall configuration of an exhaust treatment device in a vacuum exhaust system in a semiconductor manufacturing apparatus according to an embodiment of the present invention.

[0038] Refer to this Figure 1 , the overall structure of the exhaust gas treatment device is briefly described.

[0039] The exhaust treatment device is controlled according to a sequence predetermined by a program in the control device 10. A semiconductor wafer 12 is accommodated in the process chamber 11, and a process gas for process treatment and a cleaning gas for cleaning treatment (for example, a gas containing ClF3 gas or NF-based gas (nitrogen trifluoride)) are supplied through a gas supply pipe 13.

[0040] Furthermore, a dry pump 100 is connected to the process chamber 11 through a gas exhaust pipe 14 , and the process chamber 11 is depressurized to a high vacuum by driving the dry pump 100 .

[0041] That is, process gases such as silane (SiH4) gas and cleaning gases such as ClF3 (chlorine trifluoride), NF3 (nitrogen trifluoride), and HCl (hydrogen chloride) that have been processed inside the process chamber 11 (hereinafter, these process gases and cleaning gases are collectively referred to as "used gas G1") are introduced into the downstream dry pump 100 via the gas exhaust pipe 14.

[0042] In the dry pump 100 , the used gas G1 from the process chamber 11 is sucked from the gas inlet port 117 a and drawn into the dry pump 100 , and the used gas G1 is gradually pressurized in the dry pump 100 , for example, in six stages.

[0043] Furthermore, the used gas G1 pressurized to near atmospheric pressure in the dry pump 100 is discharged from the gas outlet 117b into the exhaust pipe 18, and is sent from the exhaust pipe 18 to the detoxification device 19, where it is rendered harmless and then discharged into the atmosphere.

[0044] Therefore, one end side of the exhaust pipe 18 is connected to the gas exhaust port 117 b of the dry pump 100 , and the other end side is connected to the gas introduction port 19 a of the detoxification device 19 .

[0045] In addition, an inert gas (for example, hot N 2 ) is introduced from the introduction pipe 17 , and the flow is appropriately controlled by an MFC (mass flow controller) 200 .

[0046] Figure 2 It is a schematic side cross-sectional view schematically showing the internal structure of the dry pump 100 according to the present embodiment.

[0047] Should Figure 2 The dry pump 100 shown in the figure comprises: a pump housing 123 having a plurality of (six in the present embodiment) pump chambers 122a, 122b, 122c, 122d, 122e, and 122f; rotors 124a, 124b, 124c, 124d, 124e, and 124f respectively disposed in the pump chambers 122a to 122f; and a pair of rotating shafts 125a and 125b respectively integrally fixed with the rotors 124a to 124f. , so that these rotors 124a~124f rotate integrally respectively; a pair of gears 126a, 126b, used to make the pair of rotating shafts 125a, 125b rotate synchronously; a motor 127 as a rotation drive mechanism, used to rotate the rotating shafts 125a, 125b via the pair of gears 126a, 126b; bearings 128a, 128a, 128b, 128b, respectively hold the rotating shafts 125a, 125b on the pump housing 123.

[0048] Next, the operation of the exhaust gas treatment device configured in this manner will be described.

[0049] First, when the dry pump 100 is operated under the control of the control device 10, the motor 127 is also driven, and the rotating shaft 125a is rotated by the motor 127. At this time, the rotating shaft 125b arranged parallel to the rotating shaft 125a rotates synchronously due to the meshing of the gears 126a and 126b, and the rotating shaft 125b rotates in the opposite direction to the rotating shaft 125a.

[0050] In addition, by the rotation of these rotating shafts 125a, 125b, the rotors 124a~124f integrally fixed to the rotating shaft 125a and the rotors 124a~124f integrally fixed to the rotating shaft 125b rotate in opposite directions in the pump chambers 122a~122f. In addition, although not shown in the figure, the rotors 124a~124f respectively mounted on the rotating shafts 125a, 125b in this embodiment are cocoon-shaped Roots rotors, which rotate synchronously with a phase difference of 90° while maintaining a small gap without contact with each other.

[0051] Thus, the used gas G1 is sucked from the gas inlet 117a connected to the vacuum target space to the first stage pump chamber 122a. Thereafter, the used gas G1 is sucked from the first stage pump chamber 122a to the second stage pump chamber 122b, the third stage pump chamber 122c, the fourth stage pump chamber 122d, and the fifth stage pump chamber 122e in sequence, and finally to the exhaust pipe 18 (refer to FIG. 1 ) connected to the gas exhaust port 117b of the sixth stage pump chamber 122f. Figure 1 ) is discharged from the dry pump 100, and the vacuum target space becomes a vacuum state.

[0052] At this time, the used gas G1 is discharged while being compressed in each pump chamber 122a, 122b, 122c, 122d, 122e, and 122f, so the temperature of the used gas G1 rises, and the temperature of the pump housing 123 also rises. In addition, the temperature of the used gas G1 becomes the highest on the discharge side of the sixth stage pump chamber 122f where the pressure difference of the used gas G1 between the suction side and the discharge side among the pump chambers 122a, 122b, 122c, 122d, 122e, and 122f is large. The temperature of the used gas G1 here is a relatively high temperature of, for example, about 150 to 200°C.

[0053] The used gas G1 exhausted from the sixth-stage pump chamber 122f is sent to a detoxification device 19 located several meters away via an exhaust pipe 18. Then, the detoxification device 19 performs a predetermined process.

[0054] Figure 3 This is a diagram for explaining the introduction of a cleaning gas into a vacuum exhaust system in the semiconductor manufacturing apparatus according to the present embodiment.

[0055] A heater 400 is provided on the exhaust pipe 18 connecting the dry pump 100 and the detoxification device 19 to heat the exhaust pipe 18. The exhaust pipe 18 is made of metal, and the pipe and the gasket as a sealing member are both made of metal, so that the sealing performance can be fully maintained even if the ClF3 gas is activated at high temperature.

[0056] like Figure 1 As shown in the exhaust treatment device in the vacuum exhaust system, the clean gas introduced is sucked from the process chamber 11 to the dry pump 100, and then subjected to a predetermined treatment in the detoxification device 19 to be rendered harmless. In addition, the detoxification device 19 is also connected to the emergency exhaust device 500 of the factory via the bypass line 300.

[0057] Here, the sealing member is made of a metal material having high corrosion resistance to ClF-based gas and NF-based gas (especially highly corrosive ClF3 gas) contained in the introduced cleaning gas, specifically nickel, titanium, SUS316, SUS316L, etc.

[0058] Furthermore, the exhaust pipe 18 is preferably made of a metal material having higher corrosion resistance to ClF-based gas and NF-based gas contained in the introduced clean gas than general stainless steel (eg, SUS304), specifically, SUS316, SUS316L, and Inconel.

[0059] Furthermore, when cleaning is performed, the exhaust pipe 18 connecting the dry pump 100 and the detoxification device 19 is heated by the heater 400. The target temperature is a temperature exceeding 180°C, for example, 300°C.

[0060] The ClF3 gas has the property of being stable until reaching 180° C. and being activated at a temperature exceeding 180° C. The activated ClF3 gas has an improved ability to remove products, and the cleaning efficiency is improved.

[0061] On the other hand, since the exhaust pipe 18 uses a metal (non-resin) gasket, even if the ClF 3 gas is activated, problems are unlikely to occur in terms of sealing performance.

[0062] Therefore, cleaning can be started immediately after the semiconductor manufacturing process is completed without waiting for the exhaust pipe 18 to reach 180° C., thereby shortening the time required for cleaning. In addition, time control related to temperature is no longer necessary.

[0063] Furthermore, since ClF 3 gas activated at a temperature exceeding 180° C. can be used, it is possible to save the amount of ClF 3 gas used while ensuring safety.

[0064] Description of Reference Numerals

[0065] 10: Control device

[0066] 11: Process chamber

[0067] 12: Semiconductor wafer

[0068] 13: Gas supply piping

[0069] 14: Gas exhaust piping

[0070] 17:Introduction tube

[0071] 18: Exhaust pipe

[0072] 19: Pest control device

[0073] 19a: Gas inlet

[0074] 100:Dry pump

[0075] 117a: Gas inlet

[0076] 117b: Gas exhaust port

[0077] 122a~122f: Pump room

[0078] 123: Pump housing

[0079] 124a~124f: Rotor

[0080] 125a, 125b: Rotation axis

[0081] 126a,126b: Gear

[0082] 127: Motor (rotation drive mechanism)

[0083] 128a,128b: Bearing

[0084] 200:MFC (Mass Flow Controller)

[0085] 300: Bypass pipeline

[0086] 400: Heater

[0087] 500: Emergency exhaust device

[0088] G1: Gas used.

Claims

1. A vacuum exhaust system, comprising an exhaust pipe connected to a semiconductor manufacturing device and exhausting the exhaust to a decontamination device via a vacuum pump, wherein the vacuum exhaust system is characterized in that: The sealing member used in the exhaust pipe is made of metal. A heating mechanism for heating the exhaust pipe is provided at a portion of the exhaust pipe from the vacuum pump to the detoxification device. When the cleaning gas including the ClF-based gas or the NF-based gas is introduced, the exhaust pipe is heated to a temperature exceeding 180° C. by the heating mechanism.

2. The vacuum exhaust system according to claim 1, characterized in that: The sealing member is formed of a metal material having high corrosion resistance to the clean gas.

3. The vacuum exhaust system according to claim 1 or 2, characterized in that: The exhaust pipe is formed of a metal material having high corrosion resistance to the clean gas.

4. A cleaning method, in a vacuum exhaust system including an exhaust pipe connected to a semiconductor manufacturing device and exhausting to a detoxification device via a vacuum pump, removing a product attached to the exhaust pipe by a cleaning gas including a ClF-based gas and a NF-based gas, The above cleaning method is characterized in that When the cleaning gas is introduced, the temperature of the portion of the exhaust pipe from the vacuum pump to the abatement device is heated to a temperature exceeding 180°C.

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