JP2010161150A - Gas exhaust line switching mechanism, and gas exhaust line switching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent wrong guidance of an exhaust gas to a gas exhaust line when exhaust gases from a plurality of reaction chambers are switched and exhausted to a plurality of gas exhaust lines corresponding to gas kinds, and to avoid a stop of a gas vacuum pump due to a rise in back pressure of the gas vacuum pump during the switching of the gas exhaust lines. <P>SOLUTION: A gas exhaust line switching mechanism switches and connects a plurality of vacuum pumps configured to exhaust the plurality of reaction chambers respectively to the plurality of gas exhaust lines corresponding to the kinds of gases contained in the exhaust gases discharged from the reaction chambers. A plurality of opening and closing valves are connected between the vacuum pumps and the respective gas exhaust lines, and an inert gas can be freely introduced in the upstream side of an opening and closing valve, the opening and closing valve where the inert gas is introduced being configured to form a pressure gradient such that the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a gas exhaust line switching mechanism and a switching method for switching exhaust gas to a gas exhaust line corresponding to a gas type included in the exhaust gas, and more particularly, exhaust gas is exhausted from a plurality of chambers to the gas exhaust line. This relates to switching of a gas exhaust line having a structure.

As a technique for forming an antireflection film for a solar cell, a CVD apparatus that introduces a gas such as monosilane (SiH ₄ ), ammonia (NH ₃ ), or nitrogen is known. In this CVD apparatus, when a silicon nitride film having a thickness of several tens to several hundreds of nanometers is repeatedly deposited on the substrate to be processed, the silicon nitride film is also formed on the electrode in the reaction chamber (in the chamber), the substrate susceptor, the deposition plate, or the like. It is formed. Since this silicon nitride film is an insulating film, local concentration of charges and abnormal discharge are induced in the reaction chamber, and it is impossible to maintain a film formation having a desired film thickness distribution or film quality, and the reaction occurs every several hundred batches. It is necessary to remove the silicon nitride film deposited in the chamber by a cleaning process. The reaction chamber cleaning process is performed with the reaction chamber open.

  Since the CVD apparatus heats the substrate at a film forming temperature of 400 ° C. or higher, it is necessary to lower the temperature of the reaction chamber to perform a cleaning process, and then raise the temperature of the reaction chamber again. Since it takes time to raise and lower the temperature of the reaction chamber, the cleaning process requires time required to raise and lower the temperature of the reaction chamber in addition to the maintenance time for removing deposits. There is a problem that the operation rate decreases.

Therefore, remote plasma cleaning is known in which the reaction chamber is cleaned by introducing NF ₃ into the reaction chamber without opening the reaction chamber. For example, in a reaction chamber used for a semiconductor film formation apparatus or a liquid crystal apparatus film formation apparatus, it is known to perform plasma cleaning by introducing NF ₃ and performing plasma etching to remove reaction products adhering to the reaction chamber. (See Patent Documents 1 and 2).

Japanese Unexamined Patent Publication No. 9-909 (see paragraphs 0004 to 0006, FIG. 1) Japanese Patent Laid-Open No. 9-184075 JP-A-10-321968

In a CVD apparatus that performs plasma cleaning using NF ₃ , the deposition gas and the cleaning gas are exhausted. In these gas exhausts, it is necessary to perform gas abatement for environmental protection. In order to remove this exhaust gas, the film forming gas exhaust line that guides the film forming gas exhausted from the reaction chamber to the film forming gas abatement device (thermal decomposition method) and the cleaning gas exhausted from the reaction chamber are cleaned. It is necessary to provide a cleaning gas exhaust line that leads to a gas abatement device (heating adsorption method), and to guide each exhaust gas by switching to the respective gas exhaust line.

  When connecting a film forming gas exhaust line and a cleaning gas exhaust line to a single CVD apparatus, the connection between each gas exhaust line is switched by switching the open / close valve so that the two gases do not mix with each other. The exhaust gas of the cleaning gas can be switched. However, when a plurality of CVD apparatuses are connected to the film forming gas exhaust line and the cleaning gas exhaust line, the film forming gas exhaust line and the cleaning gas exhaust line draw a pump for scrubber exhaust downstream. Due to the configuration, there is a possibility that the film forming gas is erroneously guided to the cleaning gas exhaust line, or the cleaning gas is erroneously guided to the film forming gas exhaust line.

  If the film forming gas is misguided to the cleaning gas exhaust line, for example, the temperature of the adsorbent of the cleaning gas abatement apparatus is rapidly increased, and the abatement capacity is reduced or the adsorbent is damaged. A problem occurs.

Further, when the cleaning gas is erroneously guided to the film forming gas exhaust line, for example, monosilane and NF ₃ gas react explosively inside the film forming gas abatement apparatus, and the exhaust pipe and the abatement apparatus are damaged. The problem occurs.

  9 to 11 are views for explaining a gas exhaust line switching mechanism when a plurality of CVD apparatuses are connected to the gas exhaust line.

  A gas exhaust line switching mechanism 100 shown in FIGS. 9 and 10 has a film forming gas exhaust line 102 connected to the film forming gas abatement apparatus 103 and a cleaning gas exhaust line 104 connected to the cleaning gas abatement apparatus 105. Then, the film forming gas and the cleaning gas exhausted from the CVD apparatus 111 and the CVD apparatus 121 are switched and exhausted.

  For example, in the configuration in which the exhaust gas from the CVD apparatus 111 is exhausted, an open / close valve A is provided between the vacuum pump 112 that exhausts the reaction chamber 111a of the CVD apparatus 111 and the film forming gas exhaust line 102, and the vacuum pump 112 and the cleaning are performed. An open / close valve B is provided between the gas exhaust line 104 and the open / close valves A and B are switched to open / close to switch the exhaust gas from the reaction chamber 111a to the film forming gas exhaust line 102 or the cleaning gas exhaust line 104. Exhaust. The same applies to the CVD apparatus 121.

  As shown in FIG. 11, when the film forming process is performed in the CVD apparatus 121, the opening / closing valve C is opened and the opening / closing valve D is closed, and the film forming gas exhausted from the reaction chamber is supplied to the film forming gas exhaust line 102. Exhaust. On the other hand, when performing the cleaning process in the CVD apparatus 121, the opening / closing valve C is closed and the opening / closing valve D is opened, and the cleaning gas exhausted from the reaction chamber is exhausted to the cleaning gas exhaust line 104.

  When switching from the film forming process to the cleaning process or from the cleaning process to the film forming process, it is necessary to open both the open / close valves C and D. This is because if both the open / close valves C and D are closed, the back pressure of the vacuum pump increases and the pump may stop.

  In order to avoid the stop of the pump, if a transition process is performed in which both the on-off valves C and D are opened, the pressure gradients at the inlet and outlet sides of the on-off valves C and D may reverse and reverse flow may occur. .

FIG. 9 shows a state when the CVD apparatus 121 is switched from the film forming process to the cleaning process. At this time, when both the opening and closing valves C and D are opened, the cleaning gas (NF ₃ ) exhausted from the CVD apparatus 121 is exhausted to the film forming gas exhaust line 102 (indicated by a broken line a in the figure), or cleaning is performed. When the cleaning gas (NF ₃ ) from the gas exhaust line 104 passes through the opening / closing valve D and the opening / closing valve C and is exhausted to the film forming gas exhaust line 102 (indicated by a broken line b in the figure). Further, there occurs a case in which the film forming gas (SiH ₄ ) from the film forming gas exhaust line 102 is exhausted to the cleaning gas exhaust line 104 through the opening / closing valve C and the opening / closing valve D (indicated by a one-dot chain line c in the figure). .

FIG. 10 shows a state when the CVD apparatus 121 is switched from the cleaning process to the film forming process. At this time, if both the opening and closing valves C and D are opened, the cleaning gas (NF ₃ ) from the cleaning gas exhaust line 104 is exhausted to the film forming gas exhaust line 102 through the opening and closing valve D and the opening and closing valve C ( When the cleaning gas (NF ₃ ) exhausted from the CVD apparatus 121 is exhausted to the film forming gas exhaust line 102 (indicated by a broken line “a” in the figure). Further, there occurs a case where the film forming gas (SiH ₄ ) from the film forming gas exhaust line 102 is exhausted to the cleaning gas exhaust line 102 through the opening / closing valve C and the opening / closing valve D (indicated by a one-dot chain line e in the figure). .

  Patent Document 1 is a configuration example in which exhaust gas exhausted from a plurality of reaction chambers is processed by a single abatement apparatus. In this configuration, a configuration is shown in which a combustible gas at the time of film formation and a combustion-supporting gas at the time of cleaning are prevented from being mixed in the pipe, but the exhaust gas is processed by a single abatement device. For this reason, there are no problems or configurations for the above-described opening / closing valves being simultaneously opened.

  Patent Document 1 discloses a configuration in which an inactive gas is introduced to dilute a combustible gas or a combustion-supporting gas so that the concentration in the exhaust pipe is less than the explosion limit.

  Further, in Patent Document 3, when switching to a specific exhaust path according to the type of gas to be exhausted, the gas type contained in the exhausted gas is detected and switched to the exhaust path according to the detection result. It is shown that the timing is done properly.

  However, in general, since the valve mechanism requires a predetermined time until the switching operation is completed after receiving the switching command, in a configuration in which a plurality of CVD apparatuses are connected to a plurality of gas exhaust lines, the low response of the opening / closing valve causes the above-mentioned As described above, there arises a problem that the film forming gas exhaust line 102 and the cleaning gas exhaust line 104 are connected as a result.

  Therefore, the present invention solves the above-described conventional problems, and when exhaust gas is switched from a plurality of reaction chambers to exhaust a plurality of gas exhaust lines corresponding to the gas type, the exhaust gas to the gas exhaust line is discharged. The purpose is to prevent false induction.

It is another object of the present invention to avoid stopping the pump due to an increase in the back pressure of the gas vacuum pump when switching the gas exhaust line.

  The present invention provides gas exhaust when switching a gas exhaust line for exhausting exhaust gas from a reaction chamber according to the type of exhaust gas in switching from a film forming process to a cleaning process or from a cleaning process to a film forming process. The line is switched while purging with an inert gas from the upstream side.

  This inert gas purge prevents the reversal of the pressure gradient of the on-off valve provided between the vacuum pump on the reaction chamber side and the gas exhaust line, and the gas exhaust line is generated by the backflow of gas through the on-off valve. Prevents erroneous induction of exhaust gas against

  The present invention can be an aspect of a gas exhaust line switching mechanism and an aspect of a gas exhaust line switching method.

[Gas exhaust line switching mechanism]
The aspect of the gas exhaust line switching mechanism of the present invention is that a plurality of vacuum pumps for exhausting each reaction chamber of a plurality of reaction chambers are provided with a plurality of gas exhausts corresponding to gas types contained in the exhaust gas exhausted from the reaction chambers. This is a gas exhaust line switching mechanism that connects to a line.

  In this gas exhaust line switching mechanism, a plurality of on-off valves are connected between the vacuum pump and each gas exhaust line so that an inert gas can be introduced upstream of the on-off valve, and an open / closed state in which an inert gas is introduced. The valve is configured to form a pressure gradient in which the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side.

  By introducing the inert gas upstream of the open / close valve, the pressure gradient of the open / close valve into which the inert gas has been introduced is such that the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side. This pressure gradient prevents the exhaust gas from flowing back through the open / close valve, thereby preventing the deposition gas from flowing from the deposition gas exhaust line toward the cleaning gas exhaust line, and also depositing from the cleaning gas exhaust line. Prevents cleaning gas from flowing into the gas exhaust line.

  As a result, it is possible to avoid a state in which all the on-off valves on the back pressure side of the vacuum pump are closed, and it is possible to prevent the pump from being stopped due to an increase in the back pressure of the vacuum pump.

  The vacuum pump includes a nitrogen gas introduction unit that introduces nitrogen gas, and introduces an inert gas upstream of the open / close valve by introduction of the nitrogen gas.

  The gas exhaust line includes a film forming gas exhaust line connected to a film forming gas abatement apparatus that removes the film forming gas and a cleaning gas exhaust line connected to a cleaning gas abatement apparatus that removes the cleaning gas. The inert gas introduced from the nitrogen gas introduction section is exhausted to at least one of the film forming gas exhaust line and the cleaning gas exhaust line.

The reaction chamber may be configured to include a gas introduction unit that switches between monosilane gas for depositing a silicon nitride film on the substrate to be processed and NF ₃ for plasma cleaning the silicon nitride film deposited in the reaction chamber. The film forming gas abatement device removes monosilane gas, and the cleaning gas abatement device removes NF ₃ and discharges it to the scrubber.

[Gas exhaust line switching method]
According to the aspect of the gas exhaust line switching method of the present invention, a plurality of vacuum pumps for exhausting each reaction chamber of a plurality of reaction chambers are provided, and a plurality of gas exhausts corresponding to gas types contained in the exhaust gas exhausted from the reaction chambers. This is a gas exhaust line switching method for switching to a line and connecting.

  In this aspect of the gas exhaust line switching method, when switching the type of exhaust gas to be exhausted, a plurality of on-off valves provided between the vacuum pump and each gas exhaust line are opened to open the vacuum pump and each gas exhaust line. And an inert gas is introduced upstream of the open / close valve. By introducing the inert gas, a pressure gradient is formed in the open / close valve into which the inert gas is introduced so that the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side.

  The vacuum pump includes a nitrogen gas introduction unit that introduces nitrogen gas, and introduces an inert gas upstream of the open / close valve by introduction of the nitrogen gas.

  The gas exhaust line includes a film forming gas exhaust line connected to a film forming gas abatement apparatus that removes the film forming gas and a cleaning gas exhaust line connected to a cleaning gas abatement apparatus that removes the cleaning gas. The inert gas introduced from the nitrogen gas introduction unit is exhausted to at least one of the film forming gas exhaust line and the cleaning gas exhaust line when switching the type of exhaust gas to be exhausted.

A monosilane gas for depositing a silicon nitride film on the substrate to be processed and NF ₃ for plasma cleaning the silicon nitride film deposited in the reaction chamber are switched and introduced into the reaction chamber, and the monosilane gas exhausted from the reaction chamber is formed into a film forming gas. The film forming gas abatement apparatus is exhausted through the exhaust line, and NF ₃ exhausted from the reaction chamber is exhausted through the cleaning gas exhaust line to the cleaning gas abatement apparatus.

According to the aspect of the present invention, when monosilane gas is exhausted, it is necessary to prevent the monosilane gas from flowing back to the cleaning gas exhaust line that exhausts NF ₃ to the cleaning gas abatement device, while exhausting NF ₃ . In the same way, it is necessary to prevent NF ₃ from flowing back into the film forming gas exhaust line for exhausting the monosilane gas to the film forming gas abatement apparatus. At the timing of switching between the monosilane gas and the NF ₃ exhaust gas, a nitrogen gas is continuously flowed from the upstream side to each gas exhaust line, thereby forming a pressure gradient with a low pressure on the gas exhaust line side. As a result, the exhaust gas can be prevented from flowing back from one gas exhaust line to the other gas exhaust line.

  Further, according to the aspect of the present invention, when switching the gas exhaust line while flowing down the nitrogen gas, the open / close valve provided between the vacuum pump and each gas exhaust line is opened / closed at the same time. By controlling, it is possible to avoid a situation where the pump stops due to an increase in the back pressure of the pump.

  According to the aspect of the present invention, the gas exhaust line can be switched without affecting the operating conditions of other film forming apparatuses.

  As described above, according to the gas exhaust line switching mechanism and the gas exhaust line switching method of the present invention, when the exhaust gas is switched from a plurality of reaction chambers to the plurality of gas exhaust lines corresponding to the gas type and exhausted. In addition, erroneous induction of exhaust gas to the gas exhaust line can be prevented. In addition, when switching the gas exhaust line, it is possible to avoid stopping the pump due to an increase in the back pressure of the gas vacuum pump.

It is a figure for demonstrating the structural example of the gas exhaust line switching mechanism of this invention. It is a flowchart for demonstrating the operation | movement at the time of switching from a film-forming process to a cleaning process. It is an operation | movement diagram for demonstrating operation | movement at the time of switching from a film-forming process to a cleaning process. It is an operation | movement diagram for demonstrating the operation | movement at the time of switching from a film-forming process to a cleaning process. It is a flowchart for demonstrating the operation | movement at the time of switching from a cleaning process to a film-forming process. It is an operation | movement diagram for demonstrating the operation | movement at the time of switching from a cleaning process to the film-forming process. It is an operation | movement diagram for demonstrating the operation | movement at the time of switching from a cleaning process to the film-forming process. It is a figure for demonstrating the pressure gradient of an on-off valve. It is a figure for demonstrating the gas exhaust line switching mechanism in case a some CVD apparatus is connected to a gas exhaust line. It is a figure which shows the state at the time of switching from a film-forming process to a cleaning process in a CVD apparatus. It is a figure for demonstrating the pressure gradient of an on-off valve.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a configuration example of the gas exhaust line switching mechanism of the present invention will be described with reference to FIG. 1, and an operation example will be described with reference to FIGS. FIG. 2 is a flowchart for explaining the operation when switching from the film forming process to the cleaning process, and FIGS. 3 and 4 are operation diagrams for explaining the operation when switching from the film forming process to the cleaning process. 5 is a flowchart for explaining the operation when switching from the cleaning process to the film forming process, and FIGS. 6 and 7 are operation diagrams for explaining the operation when switching from the cleaning process to the film forming process. These are the figures for demonstrating the pressure gradient of an on-off valve.

[Configuration example of gas exhaust line switching mechanism]
First, a configuration example of the gas exhaust line switching mechanism of the present invention will be described with reference to FIG.

  In FIG. 1, the gas exhaust line switching mechanism 1 has a film forming gas exhaust line 2 connected to a film forming gas abatement apparatus 3 and a cleaning gas exhaust line 4 connected to a cleaning gas abatement apparatus 5. The film forming gas and the cleaning gas exhausted from the CVD apparatus 11 and the CVD apparatus 21 are switched and exhausted.

  In the configuration in which the exhaust gas from the CVD apparatus 11 is exhausted, an open / close valve A is provided between the vacuum pump 12 for exhausting the reaction chamber 11a of the CVD apparatus 11 and the film forming gas exhaust line 2, and the vacuum pump 12 and the cleaning gas exhaust are exhausted. An open / close valve B is provided between the line 4 and the open / close valves A and B are switched to open / close, whereby the exhaust gas from the reaction chamber 11a is switched to the film forming gas exhaust line 2 or the cleaning gas exhaust line 4 and exhausted. .

  Similarly, in the CVD apparatus 21, an opening / closing valve C is provided between the vacuum pump 22 for exhausting the reaction chamber 21 a of the CVD apparatus 21 and the film forming gas exhaust line 2, and between the vacuum pump 22 and the cleaning gas exhaust line 4. Is provided with an open / close valve D, and the open / close valves C and D are switched to open / close, whereby the exhaust gas from the reaction chamber 21a is switched to the film forming gas exhaust line 2 or the cleaning gas exhaust line 4 and exhausted.

  A film-forming gas abatement device 3 is provided at the tip of the film-forming gas exhaust line 2, and a cleaning-gas abatement device 5 is provided at the tip of the cleaning gas exhaust line 4. .

The gas exhaust line switching mechanism 1 of the present invention allows nitrogen gas (N ₂ ) to be freely introduced into the vacuum pumps 12 and 22, and the open / close valves A to D are controlled to open and close by a control circuit (not shown). Each open / close valve A to D is provided with a sensor for detecting an open / close state, and a sensor signal is transmitted to the control circuit.

Here, SiH ₄ (monosilane gas), ammonia (NH ₃ ), and nitrogen (N ₂ ) are used as the film forming gas. NH ₃ is a characteristic improving gas for changing the band gap width of the deposited film.

Hereinafter, the operation of the gas exhaust line switching mechanism 1 of the present invention will be described.
First, an operation example when switching from the film forming process to the cleaning process will be described with reference to the flowchart of FIG. 2 and the operation diagrams of FIGS. Here, the operation of the on-off valves C and D for exhausting the reaction chamber 21a of the CVD apparatus 21 will be described as an example.

In FIG. 3, when the CVD apparatus 21 is in the film forming process, the opening / closing valve C is open, the opening / closing valve D is closed, and SiH ₄ (monosilane gas) or ammonia exhausted from the reaction chamber 21a. (NH ₃ ) is exhausted to the film forming gas exhaust line 2 through the opening / closing valve C. When the cleaning process for cleaning the reaction chamber 21a is started in this film forming process state (S1), the control device (not shown) stops the supply of the film forming gas to the reaction chamber 21a (S2). Then, supply of nitrogen gas (N ₂ ) to the upstream side of the open / close valves C and D is started. The supply of the nitrogen gas (N ₂₎ can be carried out by introducing nitrogen gas (N ₂₎ to a vacuum pump 22 (S3).

Next, the control device (not shown) starts the opening operation of the opening / closing valve D. When the opening / closing valve D is opened, the reaction chamber 21a and the film forming gas exhaust line 2 are in communication with each other through the opening / closing valve C, and nitrogen gas (N ₂ ) is exhausted to the film forming gas exhaust line 2 to react. The chamber 21 a and the cleaning gas exhaust line 4 are in communication with each other through the opening / closing valve D, and nitrogen gas (N ₂ ) is exhausted to the cleaning gas exhaust line 4.

FIG. 8A shows the pressure gradient of the on-off valves C and D at this time. The pressure gradient of the open / close valves C and D is such that the pressure on the inlet side (reaction chamber 21a side) is greater than that on the outlet side (film forming gas exhaust line side and cleaning gas exhaust line side) as nitrogen gas (N ₂ ) flows down. Due to this high pressure gradient, the on-off valves C and D can prevent backflow from the film forming gas exhaust line side to the cleaning gas exhaust line side (indicated by a one-dot chain line in FIG. 3). Backflow from the gas exhaust line side to the film forming gas exhaust line side can be prevented (indicated by a broken line in FIG. 3) (S4).

  In FIG. 4, when the sensor provided in the on-off valve D detects the open state of the on-off valve D (S5), the control device starts the closing operation of the on-off valve C. As a result, it is possible to prevent the open / close valves C and D from being closed at the same time, and to prevent the vacuum pump from being stopped due to an increase in the back pressure of the vacuum pump 22 (S6).

When the sensor provided in the on-off valve C detects the closed state of the on-off valve C (S7), the control device (not shown) stops supplying nitrogen gas (N ₂ ) to the reaction chamber 21a (S8), Supply of the cleaning gas (NF ₃ ) to the reaction chamber 21a is started. The cleaning gas (NF ₃ ) is exhausted through the opening / closing valve D to the cleaning gas exhaust line 4. At this time, since the opening / closing valve C is in the closed state, the cleaning gas (NF ₃ ) is exhausted to the film forming gas exhaust line 2 or from the film forming gas exhaust line 2 through the opening / closing valves C, D. It does not flow back to 4 (S9).

  First, an operation example when switching from the cleaning process to the film forming process will be described with reference to the flowchart of FIG. 5 and the operation diagrams of FIGS. Here, the operation of the on-off valves C and D for exhausting the reaction chamber 21a of the CVD apparatus 21 will be described as an example.

In FIG. 6, when the CVD apparatus 21 is in the cleaning gas process state, the opening / closing valve C is closed, the opening / closing valve D is open, and the cleaning gas (NF ₃ ) exhausted from the reaction chamber 21a is The gas is exhausted to the cleaning gas exhaust line 4 through the opening / closing valve D. In the state of the cleaning gas process, when a film forming process for forming a film in the reaction chamber 21a is started (S11), the control device (not shown) supplies the cleaning gas (NF ₃ ) to the reaction chamber 21a. (S12), and supply of nitrogen gas (N ₂ ) to the upstream side of the opening / closing valves C and D is started. This nitrogen gas (N ₂ ) can be supplied by introducing nitrogen gas (N ₂ ) into the vacuum pump 22 (S13).

Next, the control device (not shown) starts the opening operation of the opening / closing valve C. When the opening / closing valve C is opened, the reaction chamber 21a and the film forming gas exhaust line 2 are in communication with each other through the opening / closing valve C, and nitrogen gas (N ₂ ) is exhausted to the film forming gas exhaust line 2 to react. The chamber 21 a and the cleaning gas exhaust line 4 are in communication with each other through the opening / closing valve D, and nitrogen gas (N ₂ ) is exhausted to the cleaning gas exhaust line 4.

FIG. 8B shows the pressure gradient of the open / close valves C and D at this time. The pressure gradient of the open / close valves C and D is such that the pressure on the inlet side (reaction chamber 21a side) is greater than that on the outlet side (film forming gas exhaust line side and cleaning gas exhaust line side) as nitrogen gas (N ₂ ) flows down. Due to this high pressure gradient, the on-off valves C and D can prevent backflow from the film forming gas exhaust line side to the cleaning gas exhaust line side (indicated by a one-dot chain line in FIG. 6). Backflow from the gas exhaust line side to the film forming gas exhaust line side can be prevented (indicated by a broken line in FIG. 6) (S14).

  In FIG. 7, when the sensor provided in the on-off valve C detects the open state of the on-off valve C (S15), the control device starts the closing operation of the on-off valve D. As a result, it is possible to prevent the open / close valves C and D from being simultaneously closed, and to prevent the vacuum pump from being stopped due to the back pressure increase of the vacuum pump 22 (S16).

When the sensor provided on the opening / closing valve D detects the closed state of the opening / closing valve D (S17), the control device (not shown) stops supplying nitrogen gas (N ₂ ) to the reaction chamber 21a (S18), Supply of the film forming gas to the reaction chamber 21a is started. The film forming gas is exhausted to the film forming gas exhaust line 2 through the opening / closing valve C. At this time, since the opening / closing valve D is in the closed state, the film forming gas is exhausted to the cleaning gas exhaust line 4 or flows back from the cleaning gas exhaust line 4 to the film forming gas exhaust line 2 through the opening / closing valves C and D. There is nothing (S19).

  According to the embodiment of the present invention, the film forming gas and the cleaning gas exhaust gas can be introduced into the respective exhaust gas abatement apparatuses without being mixed with each other.

  According to the embodiment of the present invention, an exhaust gas treatment is performed by one set of film forming gas exhaust line and cleaning gas exhaust line without providing a plurality of exhaust lines for the film forming gas and the cleaning gas for each of the plurality of CVD apparatuses. It can be performed.

  According to the embodiment of the present invention, the exhaust gas can be switched without providing a mutual interlock between the respective CVD apparatuses, and the influence of the mutual gas exhaust can be avoided.

  The present invention is not limited to the embodiments described above. Various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

  The gas exhaust line switching mechanism and method of the present invention can be applied to the manufacture of semiconductor films and liquid crystal layers as well as solar cell antireflection films.

DESCRIPTION OF SYMBOLS 1 ... Gas exhaust line switching mechanism 2 ... Film forming gas exhaust line 3 ... Film forming gas abatement device 4 ... Cleaning gas exhaust line 5 ... Cleaning gas abatement device 11 ... CVD apparatus 11a ... Reaction chamber 12 ... Vacuum pump 11 ... CVD Equipment 21 ... CVD equipment 21a ... reaction chamber 22 ... vacuum pump 100 ... gas exhaust line switching mechanism 102 ... deposition gas exhaust line 103 ... deposition gas removal apparatus 104 ... cleaning gas exhaust line 105 ... cleaning gas removal apparatus 111 ... CVD apparatus 111a ... reaction chamber 112 ... vacuum pump 121 ... CVD apparatus 122 ... vacuum pump A to D ... open / close valve

Claims (8)

Gas exhaust line switching mechanism for switching and connecting a plurality of vacuum pumps for exhausting each reaction chamber of a plurality of reaction chambers to a plurality of gas exhaust lines corresponding to the gas types contained in the exhaust gas exhausted from the reaction chamber Because
A plurality of on-off valves are connected between the vacuum pump and each gas exhaust line;
An inert gas can be freely introduced upstream of the opening / closing valve,
A gas exhaust line switching mechanism characterized in that, in the open / close valve introduced with the inert gas, a pressure gradient is formed such that the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side. The vacuum pump includes a nitrogen gas introduction part for introducing nitrogen gas,
The gas exhaust line switching mechanism according to claim 1, wherein an inert gas is introduced upstream of the open / close valve by introducing nitrogen gas. The gas exhaust line includes a film formation gas exhaust line connected to a film formation gas removal apparatus that removes the film formation gas, and a cleaning gas exhaust line connected to a cleaning gas removal apparatus that removes the cleaning gas. Have
The gas exhaust line switching according to claim 1 or 2, wherein the inert gas introduced from the nitrogen gas introduction unit is exhausted to at least one of a film forming gas exhaust line and a cleaning gas exhaust line. mechanism. The reaction chamber includes a gas introduction unit for switching and introducing monosilane gas for depositing a silicon nitride film on the substrate to be processed and NF ₃ for plasma cleaning the silicon nitride film deposited in the reaction chamber.
4. The film forming gas abatement apparatus detoxifies monosilane gas, and the cleaning gas abatement apparatus detoxifies NF ₃ and discharges it to a scrubber. 5. Gas exhaust line switching mechanism. Gas exhaust line switching method for switching a plurality of vacuum pumps for exhausting each reaction chamber of a plurality of reaction chambers to a plurality of gas exhaust lines corresponding to gas types contained in the exhaust gas exhausted from the reaction chamber Because
When switching the type of exhaust gas to be exhausted, a plurality of on-off valves provided between the vacuum pump and each gas exhaust line are opened to connect the vacuum pump and each gas exhaust line, and the on-off valve Introducing an inert gas upstream of
A gas exhaust line switching method characterized by forming a pressure gradient in which the pressure on the vacuum pump side is higher than the pressure on the gas exhaust line side in the open / close valve into which the inert gas is introduced. The vacuum pump includes a nitrogen gas introduction part for introducing nitrogen gas,
6. The gas exhaust line switching method according to claim 5, wherein an inert gas is introduced upstream of the open / close valve by introducing nitrogen gas. The gas exhaust line includes a film formation gas exhaust line connected to a film formation gas removal apparatus that removes the film formation gas, and a cleaning gas exhaust line connected to a cleaning gas removal apparatus that removes the cleaning gas. Have
The inert gas introduced from the nitrogen gas introduction unit is exhausted to at least one of a film forming gas exhaust line and a cleaning gas exhaust line when switching the type of exhaust gas to be exhausted. 5. The gas exhaust line switching method according to 5 or 6. Into the reaction chamber, a monosilane gas for depositing a silicon nitride film on the substrate to be processed and NF ₃ for plasma cleaning the silicon nitride film deposited in the reaction chamber are switched and introduced,
The monosilane gas exhausted from the reaction chamber is exhausted to the film formation gas abatement device through the film formation gas exhaust line,
8. The gas exhaust line switching method according to claim 5, wherein NF ₃ exhausted from the reaction chamber is exhausted to a cleaning gas abatement device through a cleaning gas exhaust line.

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