JP2011049475A - Substrate treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate treatment apparatus capable of preventing an atmosphere of an exhaust line from flowing back into a treatment chamber. <P>SOLUTION: The substrate treatment apparatus includes the treatment chamber 201 for treating a substrate, the exhaust line 231 connected to the treatment chamber 201, a stop valve 243b provided to the exhaust line 231, an upstream-side pressure sensor 302 for measuring upstream-side pressure of the stop valve 243b in the exhaust line 231, a downstream-side pressure sensor 303 for measuring downstream-side pressure of the stop valve 243b in the exhaust line 231, and a controller 121 which monitors the upstream-side pressure sensor 302 and downstream-side pressure sensor 303, and opens the stop valve 243b and offsets both a pressure value of the upstream-side pressure sensor 302 and a pressure value of the downstream-side pressure sensor 303 when the pressure value of the upstream-side pressure sensor 302 is equal to or larger than that of the downstream-side pressure sensor 303. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a substrate processing apparatus.
For example, in a method for manufacturing a semiconductor integrated circuit device (hereinafter referred to as IC), the present invention relates to a semiconductor wafer that is effective for performing an oxidation process or a nitridation process on a semiconductor wafer (hereinafter referred to as a wafer) in which an IC is formed.

In an IC manufacturing method, an MMT (Modified Magnetron Typed) apparatus is used to perform oxidation treatment or nitridation treatment on a wafer. The MMT apparatus is a substrate processing apparatus that performs plasma processing on a substrate such as a wafer using a modified magnetron type plasma source that can generate high-density plasma by an electric field and a magnetic field. Since the MMT apparatus is excellent in uniformity of oxidation treatment and nitriding treatment, it is used as an oxynitriding apparatus.
In general, in an MMT apparatus, an exhaust line (exhaust system) including a vacuum pump, an exhaust valve, a pressure sensor, a controller for controlling these, and the like is connected to a processing chamber to automatically adjust the pressure in the processing chamber. ,It has been implemented. For example, see Patent Document 1.

JP 2006-5287 A

  In general, when the exhaust line evacuates the processing chamber from the atmospheric state, for example, when an error that stops the vacuum pump occurs, the processing chamber is contained. When the process chamber is contained in a high vacuum state and the error is restored and the vacuum pump resumes evacuation of the process chamber, the pressure in the process chamber is lower than the pressure in the exhaust line. There is a risk that the atmosphere of the exhaust line will flow backward into the processing chamber and the processing chamber will be contaminated.

  An object of the present invention is to provide a substrate processing apparatus that can prevent the atmosphere of an exhaust line from flowing back into a processing chamber.

Typical means for solving the above-described problems are as follows.
A processing chamber for processing the substrate;
An exhaust line connected to the processing chamber;
An on-off valve provided in the exhaust line;
An upstream pressure sensor for measuring an upstream pressure of the on-off valve in the exhaust line;
A downstream pressure sensor for measuring the downstream pressure of the on-off valve in the exhaust line;
The upstream pressure sensor and the downstream pressure sensor are monitored, and when the pressure value of the upstream pressure sensor is greater than or equal to the pressure value of the downstream pressure sensor, the on-off valve is opened, and both pressure values are A controller to offset,
A substrate processing apparatus comprising:

  According to this substrate processing apparatus, it is possible to prevent the atmosphere of the exhaust line from flowing back into the processing chamber.

It is a schematic block diagram of the MMT apparatus with which one Embodiment of this invention is implemented. It is a circuit diagram which shows an exhaust line. It is a flowchart which shows the exhaust method. It is a flowchart which shows an offset program.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

In this embodiment, the substrate processing apparatus according to the present invention is configured as an MMT apparatus that performs plasma processing on a substrate such as a wafer.
In this MMT apparatus, a substrate is installed in a processing chamber that ensures airtightness, a reaction gas is introduced into the processing chamber via a shower head, the processing chamber is maintained at a certain pressure, and high-frequency power is supplied to the discharge electrode. As a result, an electric field and a magnetic field are formed, causing magnetron discharge. Since the electrons emitted from the discharge electrode continue to circulate while continuing the cycloid motion while drifting, the lifetime is increased and the ionization generation rate is increased, so that high-density plasma can be generated. As described above, various plasma treatments are performed on the substrate by exciting and decomposing the reaction gas to subject the substrate surface to diffusion treatment such as oxidation or nitridation, forming a thin film on the substrate surface, etching the substrate surface, etc. be able to.

FIG. 1 shows a schematic configuration diagram of an MMT apparatus.
The MMT apparatus has a processing container 203. The processing container 203 is formed by a dome-shaped upper container 210 that is a first container and a bowl-shaped lower container 211 that is a second container, and the upper container 210 is placed on the lower container 211. The upper container 210 is made of a non-metallic material such as aluminum oxide or quartz, and the lower container 211 is made of aluminum.
Further, by forming a susceptor 217 which is a heater-integrated substrate holder (substrate holding means), which will be described later, with a non-metallic material such as aluminum nitride, ceramics, or quartz, metal contamination taken into the film during processing. Is reduced.

  The shower head 236 is provided in the upper part of the processing chamber 201, and includes a cap-shaped lid 233, a gas inlet 234, a buffer chamber 237, an opening 238, a shielding plate 240, and a gas outlet 239. . The buffer chamber 237 is provided as a dispersion space for dispersing the gas introduced from the gas introduction port 234.

  A gas supply pipe 232 for supplying gas is connected to the gas inlet 234, and the gas supply pipe 232 is shown in the figure via a valve 243a which is an on-off valve and a mass flow controller 241 which is a flow rate controller (flow rate control means). It is connected to the gas cylinder of the omitted reaction gas 230. The reaction gas 230 is supplied from the shower head 236 to the processing chamber 201, and the gas is exhausted to the side wall of the lower container 211 so that the gas after the substrate processing flows from the periphery of the susceptor 217 toward the bottom of the processing chamber 201. A gas exhaust port 235 is provided. A gas exhaust pipe 231 for exhausting gas is connected to the gas exhaust port 235. The gas exhaust pipe 231 is connected to a vacuum pump 246 which is an exhaust device via an APC 242 which is a pressure regulator and a valve 243b which is an on-off valve. It is connected.

  The MMT apparatus has a cylindrical electrode 215 that is a first electrode formed in a cylindrical shape, for example, a cylindrical shape, as a discharge mechanism (discharge means) that excites the supplied reaction gas 230. The cylindrical electrode 215 is installed on the outer periphery of the processing vessel 203 (upper vessel 210) and surrounds the plasma generation region 224 in the processing chamber 201. The cylindrical electrode 215 is connected to a high frequency power source 273 that applies high frequency power via a matching unit 272 that performs impedance matching.

  Cylindrical magnets 216 are disposed near the upper and lower ends of the outer surface of the cylindrical electrode 215. The cylindrical magnet 216 is a cylindrical permanent magnet formed in a cylindrical shape, for example, a cylindrical shape, and serves as a magnetic field forming mechanism (magnetic field forming means). The upper and lower cylindrical magnets 216 and 216 have magnetic poles at both ends (inner and outer peripheral ends) along the radial direction of the processing chamber 201, and the magnetic poles of the upper and lower cylindrical magnets 216 and 216 are set in opposite directions. Has been. Accordingly, the magnetic poles in the inner peripheral portion are different from each other, and magnetic lines of force are formed in the cylindrical axial direction along the inner peripheral surface of the cylindrical electrode 215.

  A susceptor 217 is disposed in the center of the bottom side of the processing chamber 201 as a substrate holder (substrate holding means) for holding the wafer 200 as a substrate. For example, the susceptor 217 is made of a non-metallic material such as aluminum nitride, ceramics, or quartz, and a heater 217b as a heating mechanism (heating means) is integrally embedded therein so that the wafer 200 can be heated. ing. The heater 217b can heat the wafer 200 to about 500 ° C. by applying electric power.

  The susceptor 217 is also equipped with a second electrode that is an electrode for changing the impedance, and the second electrode is grounded via an impedance variable mechanism 274. The impedance variable mechanism 274 includes a coil and a variable capacitor, and the potential of the wafer 200 can be controlled via the electrode and the susceptor 217 by controlling the number of coil patterns and the capacitance value of the variable capacitor.

  A processing furnace 202 for processing the wafer 200 by magnetron discharge with a magnetron type plasma source includes at least a processing chamber 201, a processing vessel 203, a susceptor 217, a cylindrical electrode 215, a cylindrical magnet 216, a shower head 236, and a gas exhaust port. The wafer 200 can be plasma-processed in the processing chamber 201.

  A shielding plate 223 is provided around the cylindrical electrode 215 and the cylindrical magnet 216. The shielding plate 223 effectively shields the electric field and magnetic field formed by the cylindrical electrode 215 and the cylindrical magnet 216 so as not to adversely affect the external environment and other processing furnaces.

  The susceptor 217 is insulated from the lower container 211 and is provided with a susceptor elevating mechanism (elevating means) 268 for elevating and lowering the susceptor 217. The susceptor 217 is provided with through-holes 217 a, and at the bottom of the lower container 211, wafer push-up pins 266 for pushing up the wafer 200 are provided at at least three locations. When the susceptor 217 is lowered by the susceptor elevating mechanism 268, the through-hole 217a and the wafer push-up pin 266 are in such a positional relationship that the wafer push-up pin 266 penetrates the through-hole 217a without contacting the susceptor 217. So that each is arranged.

  A gate valve 244 serving as a gate valve is provided on the side wall of the lower container 211. When the gate valve 244 is open, the wafer 200 can be loaded into or unloaded from the processing chamber 201 by a transfer mechanism (transfer means) not shown in the drawing. When the gate valve 244 is closed, the processing chamber 201 is hermetically closed.

  The MMT apparatus has a controller 121 as a control unit (control means). The controller 121 transmits the APC 242, the valve 243b and the vacuum pump 246 through the signal line A, the susceptor lifting mechanism 268 through the signal line B, the gate valve 244 through the signal line C, the matching unit 272 and the high frequency power supply 273 through the signal line D, The mass flow controller 241 and the valve 243a are controlled through the line E, and the heater 217b and the impedance variable mechanism 274 embedded in the susceptor are controlled through a signal line (not shown).

Next, using the MMT apparatus having the above-described configuration, a predetermined plasma treatment is performed on the surface of the wafer 200 or the surface of the base film formed on the wafer 200 as one step of the IC manufacturing method. A method will be described.
In the following description, the operation of each part constituting the substrate processing apparatus is controlled by the controller 121.

The wafer 200 is loaded into the processing chamber 201 by a transfer mechanism (not shown) that transfers the wafer from the outside of the processing chamber 201 constituting the processing furnace 202, and is transferred onto the susceptor 217.
The details of this transport operation are as follows.
The susceptor 217 is lowered to the substrate transfer position, and the tip of the wafer push-up pin 266 passes through the through hole 217a of the susceptor 217. At this time, the wafer push-up pins 266 are protruded by a predetermined height from the surface of the susceptor 217. Next, the gate valve 244 provided in the lower container 211 is opened, and the wafer 200 is placed on the tip of the wafer push-up pin 266 by a transfer mechanism (not shown). When the transfer mechanism is retracted out of the processing chamber 201, the gate valve 244 is closed. When the susceptor 217 is raised by the susceptor elevating mechanism 268, the wafer 200 can be placed on the upper surface of the susceptor 217, and further raised to a position where the wafer 200 is processed.

The heater 217b embedded in the susceptor 217 is preheated, and heats the loaded wafer 200 to a predetermined wafer processing temperature within a range of room temperature to 500 ° C.
The vacuum pump 246 and the APC 242 maintain the pressure in the processing chamber 201 at a predetermined pressure within the range of 0.1 to 100 Pa.

  When the temperature of the wafer 200 reaches the processing temperature and stabilizes, the upper surface (processing surface) of the wafer 200 disposed in the processing chamber 201 from the gas inlet 234 through the gas outlet 239 of the shielding plate 240. Introduce towards. The gas flow rate at this time is set to a predetermined flow rate within a preset range. At the same time, high frequency power is applied to the cylindrical electrode 215 from the high frequency power supply 273 via the matching unit 272. As the power to be applied, a predetermined output value in the range of 150 to 200 W is input. At this time, the impedance variable mechanism 274 is controlled in advance so as to have a desired impedance value.

  Magnetron discharge is generated under the influence of the magnetic field of the cylindrical magnets 216 and 216, charges are trapped in the upper space of the wafer 200, and high-density plasma is generated in the plasma generation region 224. Then, the surface of the wafer 200 on the susceptor 217 is subjected to plasma processing by the generated high density plasma. The wafer 200 that has been subjected to the plasma processing is transferred outside the processing chamber 201 using a transfer mechanism (not shown) in the reverse order of substrate loading.

  The details of the exhaust step (exhaust method), which is a feature of the present invention, will be described below with reference to FIGS.

FIG. 2 is a circuit diagram schematically showing an exhaust line of the MMT apparatus.
As shown in FIG. 2, a slow exhaust valve 301 that constitutes an open / close valve together with a valve 243b is connected to a gas exhaust pipe 231 as an exhaust line so as to bypass the valve 243b as a main exhaust valve. Yes. An upstream pressure sensor 302 that measures the upstream pressure of the on-off valve in the exhaust line is connected to the processing chamber 201. The upstream pressure sensor 302 may be provided between the processing chamber 201 and the valve 243b as long as it can measure the pressure in the processing chamber 201 upstream of the on-off valve. A downstream pressure sensor 303 for measuring the downstream pressure of the on-off valve in the exhaust line is connected to the gas exhaust pipe 231 downstream of the valve 243b.
The controller 121 monitors the upstream pressure sensor 302 and the downstream pressure sensor 303, performs sequence control as shown in FIG. 3, and as shown in FIG. And the downstream pressure sensor 303 are both offset controlled.

FIG. 3 is a flowchart showing an exhaust sequence.
In the first step A1, the controller 121 activates the vacuum pump 246 to evacuate the processing chamber 201.
In the second step A2, the controller 121 determines the pressure state based on the value detected by the downstream pressure sensor 303 in order to open the slow exhaust valve 301. When the vacuum pump 246 is activated and the pressure downstream from the slow exhaust valve 301 becomes equal to or lower than a preset pressure (for example, 2000 Pa or less) (YES), the controller 121 opens with respect to the slow exhaust valve 301. It determines with permission, opens the slow exhaust valve 301, and progresses to 3rd step A3.
In a third step A3, the controller 121 acquires the pressure value P ₂ of the current upstream pressure sensor 302 and a pressure value P ₃ of the current downstream pressure sensor 303, the process proceeds to the fourth step A4.

In the fourth step A4, the controller 121 determines the pressure state based on the values detected by the upstream pressure sensor 302 and the downstream pressure sensor 303, respectively. When the pressure value P ₂ of the upstream pressure sensor 302 is equal to or higher than the pressure value P ₃ of the downstream pressure sensor 303 (P ₂ ≧ P ₃ ) (YES), the controller 121 permits opening of the slow exhaust valve 301. Determine and proceed to the fifth step A5.
When P ₂ ≧ P ₃ is not established, that is, when the pressure value P ₂ of the upstream pressure sensor 302 is lower than the pressure value P ₃ of the downstream pressure sensor 303 (P ₂ <P ₃ ) (NO), the controller 121 proceeds to the eighth step A8. The eighth step A8 is an exhaust time monitoring step for monitoring the time until the condition of P ₂ ≧ P ₃ is satisfied, and when the monitoring time exceeds a certain time (YES), the process proceeds to the ninth step A9. . If the valve is released in a state where P ₂ <P ₃ , there is a possibility that the gas to be exhausted will flow backward into the processing chamber 201 and contaminate the processing chamber 201.
The ninth step A9 is an error message output step for notifying the operator that an abnormal state has occurred due to a reduction in the capacity of the vacuum pump 246 or a leak in the gas exhaust pipe 231. After executing this step, the controller 121 ends (ends) the exhaust sequence.

The fifth step A5 is a step of opening the slow exhaust valve 301. After the slow exhaust valve is opened, the controller 121 proceeds to the sixth step A6.
The sixth step A6 is a pressure value determination step of the upstream pressure sensor 302 that monitors the pressure state based on the value detected by the processing chamber 201 for opening the valve 243b as the main exhaust valve. Controller 121 if it becomes less than the pressure value is the pressure value P ₂ set in advance (e.g. 2000Pa hereinafter) (YES), the flow proceeds to the seventh step A7, opening the valve 243b.
When (NO) the pressure value P ₂ of the upstream pressure sensor 302 exceeds the set value, the controller 121 repeats the sixth step A6. That is, the process waits until the pressure in the processing chamber 201 becomes equal to or lower than the set value. When a certain time has passed, an error may be output to stop the exhaust sequence.

FIG. 4 is a flowchart showing an offset program for the upstream pressure sensor 302 and the downstream pressure sensor 303.
In the first step B1, the controller 121 determines whether or not an instruction to apply an offset to the pressure values acquired from the upstream pressure sensor 302 and the downstream pressure sensor 303 has been issued. If an instruction to offset the acquired pressure value is issued (YES), the process proceeds to the second step B2, and if not issued (NO), the offset process is terminated.
The second step B2 is an exhaust state determination step for monitoring the exhaust state of the processing chamber 201. In the activated state of the vacuum pump 246 and the open state of the main exhaust valve 243b, the pressure value of the upstream pressure sensor 302 is If the ultimate pressure has been reached (YES), the controller 121 proceeds to the third step B3, and if not reached (NO), the controller 121 proceeds to the fourth step B4.
In the third step B3, the controller 121 acquires the current pressure values of the upstream pressure sensor 302 and the downstream pressure sensor 303, and proceeds to the fifth step B5.

The fifth step B5 is a pressure value offset step in which the pressure value of the upstream pressure sensor 302 and the pressure value of the downstream pressure sensor 303 acquired in the third step B3 (pressure value acquisition step) are set to zero (Pa). is there.
The offset value is obtained as follows.
Offset value of pressure value of upstream pressure sensor 302 = 0−pressure value (P ₂ ) acquired in the fifth step B5 (pressure value acquisition step) (1)
Offset value of the downstream pressure value P ₃ of the pressure sensor 303 = 0 acquired pressure value in the fifth step B5 (pressure value acquiring _{step) (P 3) ··· (2} )
Further, the pressure value of the upstream pressure sensor 302 and the pressure value of the downstream pressure sensor 303 used in the determination after the offset are obtained by the following equations.
Determination pressure value = acquired pressure value (P ₂ , P ₃ ) + offset value (3)

  The fourth step B4 is an exhaust state determination step that is executed when the determination is NG (defective). When the offset process cannot be executed, an error message for notifying the operator is output.

  By executing the above offset program, variations in the pressure values of the upstream pressure sensor 302 and the downstream pressure sensor 303 can be absorbed, so that the usability can be improved.

By the way, there is no problem when the processing chamber 201 is evacuated from the atmospheric state. However, when a trouble that stops the exhaust sequence occurs, the main exhaust valve 243b and the slow exhaust valve 301 are closed, the processing chamber 201 is in a containment state, and the vacuuming is resumed in the containment state. When the pressure value P ₂ of the exhaust valve 301 or the main exhaust opening when the valve 243b of the upstream pressure sensor 302 is lower (P ₂ <P ₃₎ than the pressure value P ₃ of the downstream pressure sensor 303, the processing chamber A phenomenon occurs in which the atmosphere in the gas exhaust pipe 231 flows backward in 201.

However, in this embodiment, the slow exhaust valve 301 is opened only when the pressure value P ₂ of the upstream pressure sensor 302 is equal to or greater than the pressure value P ₃ of the downstream pressure sensor 303 (P ₂ ≧ P ₃ ). Therefore, a phenomenon in which the atmosphere in the gas exhaust pipe 231 flows back into the processing chamber 201 can be prevented. Therefore, contamination in the processing chamber 201 caused by a phenomenon in which the atmosphere in the gas exhaust pipe 231 flows back into the processing chamber 201 can be prevented.

  Further, by executing the offset program of the upstream pressure sensor 302 and the downstream pressure sensor 303, the usability of the backflow prevention exhaust sequence at the time of restart can be improved and the exhaust sequence can be stabilized.

  Needless to say, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  In the above embodiment, the MMT apparatus has been described. However, the present invention can be applied to all other substrate processing apparatuses.

Preferred embodiments of the present invention will be additionally described.
(1) a processing chamber for processing a substrate;
An exhaust line connected to the processing chamber;
An on-off valve provided in the exhaust line;
An upstream pressure sensor for measuring an upstream pressure of the on-off valve in the exhaust line;
A downstream pressure sensor for measuring the downstream pressure of the on-off valve in the exhaust line;
The upstream pressure sensor and the downstream pressure sensor are monitored, and when the pressure value of the upstream pressure sensor is equal to or higher than the pressure value of the downstream pressure sensor, the on-off valve is opened and both pressure values are offset together. A controller to
A substrate processing apparatus comprising:
(2) The substrate processing apparatus according to (1), wherein the upstream pressure sensor is connected to the processing chamber.
(3) The substrate processing apparatus according to (1), wherein the on-off valve includes a main exhaust valve and a slow exhaust valve.

121 controller 200 wafer (substrate)
201 processing chamber 235 gas exhaust port 243b valve (open / close valve)
246 Vacuum pump 301 Slow exhaust valve 302 Upstream pressure sensor 303 Downstream pressure sensor

Claims (1)

A processing chamber for processing the substrate;
An exhaust line connected to the processing chamber;
An on-off valve provided in the exhaust line;
An upstream pressure sensor for measuring an upstream pressure of the on-off valve in the exhaust line;
A downstream pressure sensor for measuring the downstream pressure of the on-off valve in the exhaust line;
The upstream pressure sensor and the downstream pressure sensor are monitored, and when the pressure value of the upstream pressure sensor is equal to or higher than the pressure value of the downstream pressure sensor, the on-off valve is opened and both pressure values are offset together. A controller to
A substrate processing apparatus comprising:

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