JP2007250870A - Plasma processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To blow away extraneous matters adhered to parts disposed above a processing chamber for discharging, thereby decreasing extraneous matters in the processing chamber. <P>SOLUTION: This plasma processor comprises a vacuum processing chamber 1, gas introduction means 8, 9 provided above the vacuum processing chamber 1 for introducing a process gas into the vacuum processing chamber 1, stages 2, 3 disposed in the vacuum processing chamber 1 for placing and holding a sample as a processing object, and a plasma generating means 7 provided above the vacuum processing chamber 1 for supplying high frequency electric power into the vacuum processing chamber 1 to generate a plasma. In the plasma processor for performing a plasma processing with respect to the sample with the generated plasma, the stage comprises a heat conduction gas exhaust nozzle 36 for exhausting a heat conduction gas to a heat conduction space formed between the stage and the placed sample, and an extraneous matter removing gas exhaust nozzle 21 for blowing an extraneous matter removing gas to the gas introduction means and the plasma generating means which are provided above the stage to remove the adhered extraneous matters. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus, and more particularly to a plasma processing apparatus that can remove foreign substances in a vacuum processing chamber.

  Plasma processing apparatuses are widely used in manufacturing processes for semiconductor chips and the like. The plasma processing apparatus supplies a high-frequency energy to a processing gas (reactive gas) introduced into the vacuum processing chamber via electromagnetic waves or the like to form plasma, and a silicon wafer or plasma disposed in the vacuum processing chamber by the plasmaized gas. Desired fine processing is performed on an object to be processed such as an LCD substrate.

  In the plasma processing apparatus, it is inevitable that reaction products adhere to the inside of the processing chamber as the processing of the wafer is repeated. For this reason, it is necessary to perform wet cleaning in which the vacuum processing chamber is periodically opened to the atmosphere and the inside of the processing chamber is cleaned with a chemical solution or water.

  After performing the wet cleaning that involves opening to the atmosphere, it is necessary to restore the vacuum processing chamber. In this restoration operation, the vacuum processing chamber must be evacuated to a predetermined ultimate pressure. At the time of evacuation, it is necessary to confirm the ultimate pressure of the vacuum, starting from the start of evacuation, to confirm whether there is a leak.

  In addition, when starting the plasma processing, it is necessary to check the amount of foreign matter generated during wafer transfer or plasma discharge, and check the etching rate or film formation rate.

  Thus, when performing wet cleaning, the non-operation time of the apparatus, which is the time during which semiconductor devices cannot be produced, increases, and the operation rate of the plasma processing apparatus decreases.

  By the way, when the foreign matter generation amount check inspection is performed at the time of discharge after performing the wet clean as described above, the foreign matter amount may exceed a reference value.

  In such a case, it is necessary to reduce the amount of foreign matter by repeating plasma processing (dummy processing) using a dummy wafer. However, the time required for the plasma processing using such a dummy wafer is a non-operation time of the plasma processing apparatus, and reduces the operation rate of the processing apparatus.

  By the way, the cause of foreign matter generated in the processing chamber immediately after wet cleaning is often foreign matter remaining in swap parts (consumable parts) such as a shower plate replaced during wet cleaning. In particular, there is a problem that foreign matter adhering to the swap component located above the processing chamber falls on the wafer.

  The present invention has been made in view of these problems, and provides a plasma processing apparatus capable of effectively removing foreign substances in a vacuum processing chamber.

  In order to solve the above problems, the present invention employs the following means.

  A vacuum processing chamber, a gas introduction means for introducing a processing gas into the vacuum processing chamber, and a stage disposed in the vacuum processing chamber for mounting and holding a sample which is an object to be processed; And a plasma generating device that is provided in the upper part of the vacuum processing chamber and generates plasma by supplying high-frequency power to the vacuum processing chamber, and the stage performs plasma processing on the sample by the generated plasma. , A heat transfer gas outlet for jetting heat transfer gas into a heat transfer space formed between the sample and the sample placed thereon, and a gas for removing foreign matter to the gas introduction means provided at the upper part of the stage. And a foreign substance removal gas ejection port for removing foreign substances adhered by spraying.

  Since the present invention has the above-described configuration, it is possible to effectively remove the foreign matter above the vacuum processing chamber.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram for explaining a plasma processing apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the plasma processing apparatus includes a vacuum processing chamber 1, a yoke 5 surrounding the vacuum processing chamber, a coil 6 attached to the yoke 5, an antenna 7 for supplying high-frequency power into the vacuum processing chamber 1, and a processing chamber. A gas dispersion plate 8 and a shower plate 9 that distribute and supply the processing gas, and a gas supply system 10 that supplies the processing gas to the gas distribution plate 8 and the shower plate 9 are provided.

  A temperature-adjusted refrigerant is supplied to the electrode plate constituting the antenna 7 via an antenna temperature adjustment (temperature adjustment) unit 31. Further, the antenna 7 is supplied with high frequencies from the first high frequency power source 11 and the third high frequency power source 16 via the first matching unit 12, the third matching unit 17 and the filter circuit 15, and plasma is generated in the processing chamber 1. Is generated. A second high frequency power supply 13 is connected to the stage 2 for wafer placement via a second matching unit 14 to supply a wafer bias voltage to the stage 2. The third high frequency power supply 16 and the second high frequency power supply 13 are power supplies having the same frequency, and the phase difference between them is adjusted by the phase difference adjustment unit 19.

  An antenna outer ring 20 and a silicon plate support ring 22 are provided on the outer periphery of the antenna 7, and the antenna 7 is accommodated in the antenna lid 23.

  The wafer stage 2 includes a temperature control unit 18 and supplies the temperature-adjusted refrigerant through the temperature adjustment unit into a refrigerant groove formed in the stage 2. The stage 2 includes a focus ring 4, a heat transfer gas supply source 28, a heat transfer gas supply path 28 a that supplies the heat transfer gas from the supply source 28 to the heat transfer gas outlet 36, and a heat transfer gas outlet 36. A heat transfer gas (for example, He) supplied from the gas source 28 is supplied between the surface of the stage 2 and the wafer placed on the surface via the heat transfer gas jet port 36, and the temperature of the wafer is increased. The temperature is adjusted to the temperature of the stage 2 adjusted by the adjustment unit.

  The wafer stage 2 further includes a foreign substance removal gas jet port 21 and a foreign substance removal gas introduction passage 29 for introducing the foreign substance removal gas into the foreign substance removal gas jet port 21. Further, the gas from the gas cylinder 33 in which the foreign substance removing gas (for example, an inert gas such as Ar (argon)) is accumulated is supplied to the foreign substance removing gas introduction path 29 via the mass flow controller 30 and the gas valve 32.

  The heat transfer gas supply system supplies He gas having a small mass and good thermal conductivity in order to cool the wafer. Usually, He gas is supplied at a flow rate of 5 sccm to 15 sccm. A plurality of heat transfer gas jets 36 are arranged concentrically on the surface of the stage 2.

  Next, a method for removing foreign matter will be described. First, after evacuating the vacuum processing chamber to a high vacuum (for example, 0.5 to 10 Pa), the gas valve 32 is opened to supply Ar gas. Here, the reason for using argon gas is that the mass is heavy, it is easy to blow off foreign matter, and it is relatively inexpensive.

  The Ar gas is discharged from the foreign substance removal gas jet 28 after the mass flow controller 30 adjusts a constant flow rate of 500 sccm to 3000 sccm.

  FIG. 2 is a diagram showing the flow of Ar gas, which is a foreign substance removal gas. As shown in the figure, the gas ejected from the foreign substance removal gas jet nozzle 21 flows while blowing the foreign substance through the gap formed between the shower plate 9 and the stage 2 from the center of the stage toward the outer peripheral part. By this method, foreign substances adhering to the shower plate can be reduced or removed. Note that the effect of removing foreign matter increases in proportion to the flow rate of Ar gas.

  At this time, the distance between the shower plate 9 and the stage 2 is fixed at a distance of 30 mm. At this time, the antenna temperature control unit 36 may be used to heat the antenna 7. When the antenna 7 is heated, the shower plate 9 and the silicon plate support ring 22 are heated by heat conduction. At this time, the foreign matter adhering to the shower plate 9 and the silicon plate support ring 22 is also heated by heat conduction, and the internal energy of the foreign matter is increased. As a result, the adhered foreign matter is easily peeled off.

  Further, the flow rate of the gas ejected from the foreign substance gas removal gas ejection port 21 may not be constant. For example, the gas valve 32 may be intermittently opened for several seconds at intervals of 5 to 60 seconds to flow the gas in a pulsed manner. When the gas is flowed in a pulse manner as described above, it is not necessary to adjust the flow rate by the mass flow controller 9.

FIG. 3 is a diagram illustrating an example in which an air storage tank is attached to the foreign substance removal gas supply path. In the figure, the same parts as those shown in FIG. As shown in FIG. 3, an air storage tank 34 is attached instead of the mass flow controller 30 shown in FIG. When supplying the foreign substance removal gas, first, the high pressure gas is supplied from the cylinder 33 and stored in the storage tank 34 with the valve 32 closed. Next, the valve 32 is opened, and the high-pressure gas stored in the air storage tank 34 is released. The released gas flows through the gap between the shower plate 9 and the stage 2 while blowing off foreign matter from the center of the stage toward the outer periphery. According to this method, it is possible to supply a large amount of foreign substance removal gas in a short time.
FIG. 4 is a diagram for explaining an example of ejecting the foreign substance removal gas through the heat transfer gas supply system. In the figure, the same parts as those shown in FIG. As shown in FIG. 4, the foreign substance removal gas introduction system including the gas cylinder 33 in which the foreign substance removal gas is accumulated, the mass flow controller 30, the gas valve 32, and the foreign substance gas introduction path is connected to the heat transfer gas jet through the heat transfer gas supply path 28a. Connect to the exit. When supplying the foreign matter removal gas, the valve 32 that connects the heat transfer gas supply source 28 and the heat transfer gas supply path 28a is closed, the valve 32 is opened, and the Ar from the gas cylinder 33 in which the foreign matter removal gas is accumulated. Gas is supplied to the heat transfer gas outlet 36 through the mass flow controller 30 at a flow rate of 500 sccm to 3000 sccm, and Ar gas is jetted from the heat transfer gas outlet 36. The ejected gas flows through the gap between the shower plate 9 and the stage 2 while blowing off foreign matters from the center of the stage toward the outer periphery. According to this method, it is possible to supply the foreign substance removal gas evenly from a plurality of locations to the shower plate.

  As shown in FIG. 3, a gas storage tank 34 is attached instead of the mass flow controller 30, and when supplying the foreign substance removal gas, first, the high pressure gas is supplied from the cylinder 33 to the gas storage tank 34 with the valve 32 closed. And accumulate. Next, the valve 32 may be opened so that the high-pressure gas stored in the gas storage tank 34 is ejected from the heat transfer gas ejection port. In this case, the jetted gas flows through the gap between the shower plate 9 and the stage 2 while blowing away foreign substances from the center of the stage toward the outer periphery. According to this method, it is possible to supply a large amount of foreign substance removal gas in a short time.

  FIG. 5 is a view for explaining a plasma processing apparatus according to the second embodiment of the present invention. In the second embodiment, the stage 2 (fixed stage) in the first embodiment is changed to a movable stage 3. Except for the changes associated with this change, the description is omitted because it overlaps with the first embodiment.

  As shown in FIG. 5, as the stage 2 is changed to the movable stage 3, the bellows 24 that hermetically separates the stage driving unit 27 and the vacuum processing chamber 1, the stage upper cover 25 that covers the lower part of the stage 2, and the stage A lower cover 26 is provided. The stage drive unit 27 is disposed on the atmosphere side of the apparatus, and drives the operation stage 3 in the vertical direction (direction approaching and moving away from the shower plate 9).

  When removing the foreign matter, first, the vacuum processing chamber is evacuated to a high vacuum (for example, 0.5 to 10 Pa), and then the stage driving unit 27 is operated to raise the movable stage 3 to the upper limit position. For example, the distance between the shower plate 9 and the movable stage 3 is made to approach 1 mm. Note that the closer this distance is, the greater the effect of blowing off foreign matter (which increases in inverse proportion to the distance). Therefore, since the distance between the shower plate 9 and the movable stage 3 is shorter than that in the first embodiment, more foreign matters can be reduced.

  Next, the gas valve 32 is opened to supply Ar gas. Ar gas is discharged from the foreign substance removal gas jet port 21 after the mass flow controller 30 adjusts a constant flow rate of 500 sccm to 3000 sccm. It should be noted that the effect of blowing off foreign matters increases in proportion to the flow rate of Ar gas.

  FIG. 6 is a diagram showing the flow of Ar gas, which is a foreign substance removal gas. As shown in the figure, the gas ejected from the foreign substance removal gas jet nozzle 21 flows while blowing the foreign substance through the gap formed between the shower plate 9 and the stage 2 from the center of the stage toward the outer peripheral part. By this method, foreign substances adhering to the shower plate can be reduced or removed. Note that the effect of removing foreign matter increases in proportion to the flow rate of Ar gas.

  At this time, the antenna temperature control unit 36 may be used to heat the antenna 7. When the antenna 7 is heated, the shower plate 9 and the silicon plate support ring 22 are heated by heat conduction. At this time, the foreign matter adhering to the shower plate 9 and the silicon plate support ring 22 is also heated by heat conduction, and the internal energy of the foreign matter is increased. As a result, the adhered foreign matter is easily peeled off.

  Further, the flow rate of the gas ejected from the foreign substance gas removal gas ejection port 21 may not be constant. For example, the gas valve 32 may be intermittently opened for several seconds at intervals of 5 to 60 seconds to flow the gas in a pulsed manner. When the gas is flowed in a pulse manner as described above, it is not necessary to adjust the flow rate by the mass flow controller 9.

FIG. 7 is a diagram illustrating an example in which an air storage tank is attached to the foreign substance removal gas supply path. In the figure, the same parts as those shown in FIG. As shown in FIG. 7, an air storage tank 34 is attached in place of the mass flow controller 30 shown in FIG. When supplying the foreign substance removal gas, first, the high pressure gas is supplied from the cylinder 33 and stored in the storage tank 34 with the valve 32 closed. Next, the valve 32 is opened, and the high-pressure gas stored in the air storage tank 34 is released. The released gas flows through the gap between the shower plate 9 and the stage 2 while blowing off foreign matter from the center of the stage toward the outer periphery. According to this method, it is possible to supply a large amount of foreign substance removal gas in a short time.
FIG. 8 is a diagram for explaining an example of ejecting the foreign substance removal gas through the heat transfer gas supply system. In the figure, the same parts as those shown in FIG. As shown in FIG. 8, the foreign matter removal gas introduction system including the gas cylinder 33 in which the foreign matter removal gas is accumulated, the mass flow controller 30, the gas valve 32, and the foreign matter gas introduction passage, Connect to the exit. When supplying the foreign matter removal gas, the valve 32 that connects the heat transfer gas supply source 28 and the heat transfer gas supply path 28a is closed, the valve 32 is opened, and the Ar from the gas cylinder 33 in which the foreign matter removal gas is accumulated. Gas is supplied to the heat transfer gas outlet 36 through the mass flow controller 30 at a flow rate of 500 sccm to 3000 sccm, and Ar gas is jetted from the heat transfer gas outlet 36. The ejected gas flows through the gap between the shower plate 9 and the stage 2 while blowing off foreign matters from the center of the stage toward the outer periphery. According to this method, it is possible to supply the foreign substance removal gas evenly from a plurality of locations to the shower plate.

As shown in FIG. 7, a gas storage tank 34 is attached instead of the mass flow controller 30. When supplying the foreign substance removal gas, first, the high pressure gas is supplied from the cylinder 33 to the gas storage tank 34 with the valve 32 closed. And accumulate. Next, the valve 32 may be opened so that the high-pressure gas stored in the gas storage tank 34 is ejected from the heat transfer gas ejection port. In this case, the jetted gas flows through the gap between the shower plate 9 and the stage 2 while blowing away foreign substances from the center of the stage toward the outer periphery. According to this method, it is possible to supply a large amount of foreign substance removing gas in a short time. In the above, an example using a magnetic field parallel plate type plasma source as a plasma processing apparatus has been described. However, according to the present invention, the foreign matter removal gas is blown upward from the lower side of the processing chamber, so that the foreign matter after wet cleaning adhering to the parts arranged above the processing chamber, for example, the shower plate, is blown off to reduce the foreign matter. It is something to be made. Therefore, there is no limitation on the type of plasma source. Therefore, the present invention can be similarly applied to a plasma processing apparatus using a magneticless parallel plate plasma source, an inductively coupled plasma source, a microwave ECR plasma source, or the like.

  As described above, according to the present embodiment, the foreign matter in the processing chamber is reduced by blowing away and exhausting the foreign matter after wet cleaning adhering to the parts arranged above the processing chamber, for example, the shower plate. Can be made. For this reason, the time required for the dummy process can be reduced or the dummy process can be omitted. Thereby, the number of dummy wafers to be used can be reduced, and the operating rate of the plasma processing apparatus can be improved.

It is a figure explaining the plasma processing apparatus concerning 1st Embodiment. It is a figure which shows the flow of Ar gas which is a foreign material removal gas. It is a figure explaining the example which attached the air storage tank to the foreign material removal gas supply path. It is a figure explaining the example which ejects foreign material removal gas via a heat transfer gas supply system. It is a figure explaining the plasma processing apparatus concerning 2nd Embodiment. It is a figure which shows the flow of Ar gas which is a foreign material removal gas. It is a figure explaining the example which attached the air storage tank to the foreign material removal gas supply path. It is a figure explaining the example which ejects foreign material removal gas via a heat transfer gas supply system.

Explanation of symbols

1 Vacuum processing chamber 2 Stage (fixed)
3 movable stage 4 focus ring 5 yoke 6 coil 7 antenna 8 gas dispersion plate 9 shower plate 10 processing gas supply system 11 first high frequency power source 12 first matching unit 13 second high frequency power source 14 second matching unit 15 filter circuit 16 third High-frequency power supply 17 Third matching unit 18 Temperature control unit 19 Phase adjustment unit 20 Antenna outer ring 21 Foreign matter removal gas jet port 22 Silicon plate support ring 23 Antenna lid part 24 Bellows 25 Stage upper cover 26 Stage lower cover 27 Stage drive part 28 Heat gas supply source 28a Heat transfer gas supply path 29 Foreign matter removal gas supply path 30 Mass flow controller 31 Antenna temperature control unit 32, 35 Gas valve 33 Gas cylinder 34 Air storage tank 36 Heat transfer gas outlet

Claims (6)

A vacuum processing chamber;
A gas introduction means provided at an upper portion of the vacuum processing chamber, for introducing a processing gas into the vacuum processing chamber;
A stage placed and held in the vacuum processing chamber for placing and holding a sample to be processed;
In the plasma processing apparatus provided at the upper part of the vacuum processing chamber, comprising plasma generating means for generating plasma by supplying high-frequency power to the vacuum processing chamber, and performing plasma processing on the sample by the generated plasma,
The stage has a heat transfer gas jet port for jetting heat transfer gas into a heat transfer space formed between the placed sample and the stage,
A plasma processing apparatus, comprising: a foreign substance removal gas jet port for removing foreign substances adhering to the gas introduction means provided on the stage by blowing a foreign substance removal gas. A vacuum processing chamber;
A gas introduction means provided at an upper portion of the vacuum processing chamber, for introducing a processing gas into the vacuum processing chamber;
A stage placed and held in the vacuum processing chamber for placing and holding a sample to be processed;
Stage driving means for raising and lowering the stage in the vacuum processing chamber;
In the plasma processing apparatus provided at the upper part of the vacuum processing chamber, comprising plasma generating means for generating plasma by supplying high-frequency power to the vacuum processing chamber, and performing plasma processing on the sample by the generated plasma,
The stage has a heat transfer gas jet port for jetting heat transfer gas into a heat transfer space formed between the placed sample and the stage,
A plasma processing apparatus, comprising: a foreign substance removal gas jet port for removing foreign substances adhering to the gas introduction means provided on the stage by blowing a foreign substance removal gas. The plasma processing apparatus according to claim 1 or 2,
The plasma processing apparatus, wherein the heat transfer gas ejection port and the foreign substance removal gas ejection port are connected to a common gas supply path. The plasma processing apparatus according to claim 1 or 2,
A plasma processing apparatus, wherein a gas supply path for supplying gas to the foreign matter removal gas jetting port includes a gas storage tank, and the foreign substance removal gas is intermittently supplied through the gas storage tank. The plasma processing apparatus according to claim 2, wherein
A plasma processing apparatus, wherein a foreign substance removing gas is ejected from the foreign substance removing gas jet outlet at a position where the stage is raised to the uppermost position. A vacuum processing chamber;
A gas introduction means provided at an upper portion of the vacuum processing chamber, for introducing a processing gas into the vacuum processing chamber;
A stage placed and held in the vacuum processing chamber for placing and holding a sample to be processed;
In the plasma processing apparatus provided at the upper part of the vacuum processing chamber, comprising plasma generating means for generating plasma by supplying high-frequency power to the vacuum processing chamber, and performing plasma processing on the sample by the generated plasma,
The stage has a heat transfer gas outlet for jetting heat transfer gas into a heat transfer space formed between the placed sample and a supply for supplying a foreign substance removal gas to the heat transfer gas outlet. With a road,
A plasma processing apparatus for removing foreign matter adhering by spraying a foreign matter removing gas from the heat transfer gas outlet to the gas introducing means provided on the upper part of the stage.

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