JP2012054491A - Vacuum processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus capable of realizing enlargement of a pressure adjusting area in a processing chamber by making a vacuum container in such a shape that gas is easy to flow and at the same time adding a pressure adjustment mechanism thereto, as well as by using a gate valve as a variable conductance valve in the vacuum container to adjust a gas exhaust.SOLUTION: Etching gas is arranged to flow at the upper part of an electrode part 211 of a processing chamber 210 in a plasma processing apparatus to generate plasma by applying an electric wave introduced by a discharger 200 so as to etch a wafer on the electrode part 211. The gas used for the etching treatment and particles of a product material and the like produced by the etching treatment are exhausted by an exhaust part 220; the gas and the particles of the product material and the like through a chamber 221, a gate valve 222, and a vacuum pump 223. As means to achieve a prescribed pressure at the time of the etching treatment, the chamber 221 with coax and capable of moving in the axial direction and the gate valve 222 capable of opening both left and right ways are used to control the pressure.

Description

  The present invention relates to a plasma processing apparatus in which a plasma is formed inside and a sample such as a semiconductor wafer is processed, and in particular, a pressure within a desired pressure range in the processing chamber by adjusting a variable conductance unit provided in the processing chamber. The present invention relates to a vacuum processing apparatus such as a plasma processing apparatus that performs adjustment.

  In the plasma processing apparatus as described above, in recent years, in order to realize a fine and highly accurate processing of a sample such as a semiconductor wafer, it is required to form a higher density and more uniform plasma.

  In order to stably form such high-density plasma, it is required to more stably realize the pressure in the processing chamber in the vacuum vessel with a higher degree of vacuum (lower pressure). In such a conventional plasma processing apparatus, a vacuum pump for exhausting particles such as gas and plasma inside the processing chamber and products generated by processing in the processing chamber into the processing chamber disposed inside the vacuum vessel. Etc. are connected and connected.

  Furthermore, a device for adjusting the amount of exhaust per unit time is disposed on the exhaust passage communicating from the processing chamber toward the inlet of the vacuum pump, and the gas and particles in the processing chamber by the operation of the adjusting device. By adjusting the amount of exhaust gas, the pressure inside the processing chamber in which plasma is formed is adjusted.

  In the conventional plasma processing apparatus, the resistance of the flow of gas discharged between the exhaust port and the inlet of the passage connecting the exhaust port at the lower part of the processing chamber in the vacuum vessel and the inlet of the vacuum pump and the flowability (conductance) are reduced. A means for adjusting was arranged to adjust the amount of gas discharged from the vacuum vessel, thereby adjusting the pressure inside the vacuum vessel.

  As a means for adjusting the flow resistance and the ease of flow, a valve that changes the size or area of the passage or the opening of the inlet or exhaust port is considered. It is known to adjust the size and area of the opening by moving in a direction across the window.

  An example of such a prior art is disclosed in Patent Document 1, for example. In this prior art, a substantially circular opening that is disposed immediately below a sample stage for placing a wafer as a sample in the processing chamber and from which the gas in the processing chamber is discharged, and a gas that is disposed below the opening and that is provided with gas. It is known that a plurality of rotating plate-like valves are provided between a vacuum pump for evacuation and the area of a passage through which a gas can pass is variably adjusted by the rotation of these valves.

  As another conventional technique, there is known a technique in which a plate-like valve (gate valve) moving in the horizontal direction is used to variably adjust the area of a passage through which gas can pass to adjust the internal pressure of the vacuum vessel. Such a prior art is disclosed in Patent Document 2.

JP 2005-101598 A Japanese Patent Laid-Open No. 2-52428

  However, the above-described prior art has a problem because the following points are not sufficiently considered.

  That is, in the prior art disclosed in Patent Document 1, in order to make the processing chamber into a higher vacuum state, the plate-shaped valve needs to have a large opening (or opening area). At a large opening, the accuracy of adjusting the pressure is lowered.

  That is, in order to realize such a large opening, each valve is rotated to reduce the angle of each valve with respect to the axial direction of the passage (the face of the valve becomes parallel to the axis of the passage), In this state, the pressure in the processing chamber is small, and the change in the gas discharge amount with respect to the change in the angle of each valve is small, so the controllability is reduced and the high degree of vacuum is stabilized with high accuracy. There was a problem that could not be realized.

  On the other hand, in the prior art disclosed in Patent Document 2, by using a gate valve as a variable conductance valve provided in the processing chamber, the gate itself does not become an exhaust resistance, and the area of the entire passage can be varied. Therefore, it is possible to make the processing chamber have a lower pressure.

  However, when adjusting the pressure in the gate valve, the conductance is changed by moving the gate of the gate valve. However, as the exhaust port area is increased, the amount of movement of the gate relative to the exhaust port area (valve The increase in exhaust port area due to the opening degree of the gas does not increase, so that the change in gas discharge becomes smaller and the pressure change decreases. Therefore, there is a problem that only pressure adjustment by the valve opening degree can be used.

  Furthermore, when exhausting particles such as gas and products generated by processing in the processing chamber, the valve passes through the valve. At that time, particles such as gas and product adhere to the valve and periodic cleaning is performed. is necessary. At this time, since the valve is located at a position where the exhaust port in the lower part of the processing chamber in the vacuum vessel communicates with the inlet of the vacuum pump, the cleaning operation becomes difficult and takes a lot of time.

  An object of the present invention is to adjust a gas exhaust by using a gate valve as a variable conductance valve provided in a vacuum vessel and to make the vacuum vessel into a shape in which a gas can easily flow (good conductance) and at the same time pressurize the vacuum vessel. An object of the present invention is to provide a plasma processing apparatus capable of realizing an expansion of a pressure adjustment region in a processing chamber by providing an adjusting mechanism.

  In addition, a gate valve that can be equipped with a heater at the gate part of the gate valve and has a swap structure with a cover reduces foreign substances (gas and reactive products) adhering to the gate valve, and also shortens the cleaning work time. Is to provide.

  In order to achieve the above object, a vacuum processing apparatus of the present invention comprises a vacuum processing chamber, an exhaust means for evacuating the vacuum processing chamber, a valve for controlling the pressure in the vacuum processing chamber, and the vacuum processing. A vacuum processing apparatus provided with a mounting electrode on which a substrate to be processed is mounted, wherein the exhaust means is disposed below the mounting electrode, coaxially exhausts the vacuum processing chamber, and the valve Is a gate valve.

  In the vacuum processing apparatus of the present invention, the vacuum processing chamber further includes a chamber having a two-part structure in which a cylindrical chamber upper portion and a chamber lower portion are fitted and movable in the axial direction, and the gate valve is A gate that can be opened and closed to the left and right is provided around the axis of the vacuum processing chamber that is coaxially evacuated by the cylindrical chamber.

  Further, in the vacuum processing apparatus of the present invention, the cylindrical chamber upper portion and the chamber lower portion are fitted so as to be movable in the axial direction via a plurality of O-ring seal portions, and the cylindrical chamber is It is characterized by comprising a chamber lifting device that is movable in the axial direction.

  In the vacuum processing apparatus according to the present invention, the gate valve includes a maintenance cover.

  In the vacuum processing apparatus of the present invention, the maintenance cover includes a partly removable cover provided on the gate valve and a replaceable cover provided on the surface of the gate. Features.

  In the vacuum processing apparatus of the present invention, a plurality of gates that can be opened and closed left and right about the axis of the vacuum processing chamber are connected to each other, and when the gate valve is 100% open, The gates overlap each other in the vertical direction and are stored in the storage unit. When the gate valve is closed, the movement of the uppermost gate is controlled to close the opening of the gate valve.

  In the vacuum processing apparatus of the present invention, the gate of the gate valve includes a heater.

  The vacuum processing apparatus of the present invention is a plasma processing apparatus, an LCD etching apparatus, or a plasma CVD apparatus.

  According to the present invention, the expansion of the pressure adjustment region in the vacuum processing chamber can be realized, and foreign substances (gas and reactive products) adhering to the gate valve can be reduced, and the cleaning operation time can be shortened. Can do.

FIG. 1 is a graph showing pressure control of a butterfly valve and a gate valve. FIG. 2 is a diagram showing an outline of the configuration of the plasma processing apparatus according to the present invention. FIG. 3 is a diagram showing an outline of the etching chamber of the plasma processing apparatus according to the present invention. FIG. 4 is a view showing the structure of the chamber of the present invention. FIG. 5 shows the structure of the gate valve of the present invention. FIG. 6 is a view showing the structure of a gate valve provided with two O-ring seal portions. FIG. 7 is a view showing a two-divided gate valve structure (one on one gate side) according to the present invention. FIG. 8 is a view showing a two-divided gate valve structure (four pieces on one gate side) of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a graph showing pressure control by a butterfly valve and a gate valve. In the pressure control with a butterfly valve, the pressure change near 0% to 30% of the valve opening is large and moderate at 30% to 60%, and the pressure change with respect to the valve opening is small at 60% to 100%. .

  On the other hand, in the pressure control by the gate valve, the pressure change is large when the valve opening degree is 20% to 40%, and is gentle when the valve opening is 40% to 70%, and the pressure change is small when the pressure is 70% to 100%. When the pressure is controlled, if the pressure change is large with respect to the valve opening, even if fine opening adjustment of the valve is performed, control with a large pressure change cannot be obtained.

  On the other hand, even if the pressure change is too small with respect to the valve opening, it cannot cope with the change in the gas flow rate or the pressure change due to the increase in the flow rate due to the reactive product generated by etching, and the pressure control becomes impossible. Therefore, pressure control during processing is difficult unless the pressure change with respect to the valve opening is gradual. Therefore, by using the gate valve as the variable conductance valve, it is possible to control the pressure in the low pressure region.

  FIG. 2 is a top view schematically showing the configuration of the plasma processing apparatus according to the present invention. The plasma processing apparatus according to the present invention is roughly composed of an atmospheric processing unit and a vacuum processing unit.

  The atmospheric processing unit is composed of a cassette stand 100 and an atmospheric transfer chamber 110. The cassette stands 100 are arranged in parallel and are arranged in front of the atmospheric transfer chamber 100, and have a role of placing a cassette. The atmospheric transfer chamber 110 is provided with an atmospheric robot for moving the wafer, and has a role of moving the wafer from the cassette table 100 to the lock chamber 120.

  The vacuum processing unit includes a lock chamber 120, a vacuum transfer chamber 130, an etching chamber 140, and an ashing chamber 150. The lock chamber 120 is located on the back surface of the atmospheric transfer chamber 110 and has a structure capable of adjusting pressure to move the wafer from the atmospheric transfer chamber 110 to the vacuum transfer chamber 130 or from the vacuum transfer chamber 130 to the atmospheric transfer chamber 110. It has become. The vacuum transfer chamber 130 is provided with the lock chamber 120, the etching chamber 140, and the ashing chamber 150 on the side surface, so that an opening is provided on the side surface, and the opening is opened and closed by a gate valve.

  In addition, a vacuum robot is installed and has a role of moving the wafer to each unit in the vacuum. In the upper part of the vacuum transfer chamber 130, a hexagonal hole is provided for maintenance in the vacuum transfer chamber 130, which is sealed with a lid. The etching chamber 140 is evacuated to perform wafer etching. The ashing chamber 150 removes the resist that is no longer necessary for the wafer etched in the etching chamber 140 in a vacuum.

  FIG. 3 is a cross-sectional view schematically showing the configuration of the etching chamber 140 according to the present invention shown in FIG. The etching chamber 140 is roughly divided into a discharge unit 200, a processing chamber 210, and an exhaust unit 220, which are coaxially positioned.

  In the discharge unit 200, a radio wave source 201 that generates radio waves, an auto tuner 202 that adjusts radio waves, a waveguide 203 through which radio waves pass, and a coil 204 that generates a magnetic field are positioned so that radio waves are introduced into the processing chamber 210. It has become. A gas introduction part (not shown) and an electrode part 211 are located in the processing chamber 210, an etching gas is supplied to the upper part of the electrode, and plasma is generated by applying radio waves introduced from the discharge part 200 to etch the wafer. To do. The gas used for the etching process and the particles such as the product generated by the etching process are exhausted through the chamber 221, the gate valve 222, and the vacuum pump 223 in the exhaust unit 220.

  At this time, control is performed using the chamber 221 and the gate valve 222 as means for obtaining a desired pressure during the etching process.

  FIG. 4 is a diagram showing the structure of the chamber 221 used for pressure control. The chamber 221 is cylindrical and has a two-part structure. Further, a part of the chamber upper part 300 and the chamber lower part 310 are fitted to each other and can be moved in the axial direction. In addition, each of the upper chamber portion 300 and the lower chamber portion 310 is supported by a base.

  The shape of the chamber upper portion 300 is such that a lid capable of holding a vacuum is attached, and an opening serving as a wafer entrance is provided on the side surface so that a coil raising / lowering device 320 for raising and lowering the coil 204 is attached. It has become.

  In addition, the chamber upper portion 300 and the chamber lower portion 310 are shaped to fit with each other. The chamber lower portion 310 is shaped to fit the chamber upper portion 300, and a chamber lifting / lowering device 330 that can move the chamber in the axial direction is attached to the side surface.

  In FIG. 4, only one chamber lifting device 330 is provided, but a plurality of chamber lifting devices 330 may be provided. However, in the case of providing a plurality, it is necessary to provide a mechanism for tuning.

  As a vacuum seal means for the chamber upper part 300 and the chamber lower part 310, an O-ring groove is provided in the circumferential direction, and a means using a shaft seal is taken. When the shaft seal is used, the O-ring collapses due to an influence of a gap or the like of the fitting portion where the O-ring seal portion 340 exists. The greater the deviation of the collapse of the O-ring, the higher the number of leaks that cannot be maintained.

  Therefore, by instructing mechanical and geometrical tolerances to the fitting portions of the chamber upper portion 300 and the chamber lower portion 310, the influence due to the gaps of the fitting portions is reduced and the bias of the O-ring seal is reduced.

  Further, as shown in FIG. 5, by providing two or more O-ring seal portions 340 at a certain distance, the inclination of the fitting portion can be suppressed and the O-ring can be prevented from collapsing. A reliable vacuum seal can be obtained.

  In the chamber control, the pressure characteristics at each chamber position are stored in advance in the apparatus, and by inputting or setting a desired pressure, the chamber lifting / lowering apparatus 330 moves to the chamber position corresponding to the pressure and conductance is performed. To change. By providing a variable conductance portion that moves the chamber in the axial direction, the base pressure can be adjusted even if the pressure controllable range is determined by the gate valve 222. Therefore, the usable range from high pressure to low pressure can be expanded.

  FIG. 6 is a view showing the structure of the gate valve 222. The gate valve 222 is a variable conductance valve in which the gate 410 can move in the horizontal direction, and the gate 410 is a plate having a substantially circular shape and a size that matches the chamber shape. A heater 440 is provided inside the gate 410, and when the gate valve is used, the gate can be heated to increase the surface temperature of the gate. The gate valve container 450 is provided with a partly removable cover 420 and a replaceable cover 430 on the gate surface.

  When cleaning the gate valve 222, the gate 410 is fully closed, and the cover 420 that can be partially removed is removed, and then the replaceable cover 430 is replaced.

  The gate valve 222 is controlled by detecting the pressure in the processing chamber and driving a driving device (for example, an electric cylinder) by a microprocessor (not shown) based on this detection signal, moving the gate 410, and changing the opening area of the gate valve 222. Do it.

  In FIG. 6, the gate 410 is stored in one place. However, the gates 601, 602, 604, and 605 may be stored in two places as shown in FIGS.

  FIG. 7 is a diagram showing a gate valve that opens and closes by one gate on each side. The gate valve 600 is a variable conductance valve that can move the gate 601 and the gate 602 in the horizontal direction. The valve 100% is closed when the gate 601 and the gate 602 move to the center of the gate opening. A driving device (for example, an electric cylinder) is installed at each gate, and each gate can move independently.

  The gate valve 600 has a feature that does not require an uneven mounting space because the gate is divided into two. In addition, since the gate can be opened and closed from the center of the axis of the opening to the left and right, it is possible to reduce the eccentricity of the exhaust gas around the axis of the chamber.

  FIG. 8 is a view showing a gate valve 603 that is opened and closed by four gates 604 on one side. The gate valve 603 is a variable conductance valve that can move the gate 604 in the horizontal direction. The gate 604 is composed of four gates on one side (a total of eight gates on both sides). When the gate is 100% open, the four gates overlap each other in the vertical direction.

  In addition, when the gate 604 is moved, the gate 605 located at the top is moved by a driving device, and a shape like a protrusion is provided on each gate so as to be caught by the gate installed above. It is possible to connect four gates.

  Since the four gates are connected, the driving device can open and close the gate 604 one by one on each side. Moreover, since the gates 604 and 604 are stored in two places, an uneven mounting space is not required. In addition, by mounting the gates on four sides on one side, the mounting space for storing the gates 604 and 604 can be reduced.

  In addition, if the gate valve opening / closing port is substantially circular, there is a difference in opening area depending on the gate opening / closing position. Therefore, as the gate valve opening increases, the increase in opening due to the opening / closing position decreases. (Ease of gas flow) is promoted, but by making the opening rectangular and rectangular, only the change of the area due to the movement of the gate is made, so the decrease of the open conductance change by the open / close position is promoted. It can also be prevented.

  The present invention has been described with reference to the case where the present invention is applied to a plasma processing apparatus. However, the present invention is not limited to the above-described embodiment, and the present invention is not limited to the above-described embodiments. Also effective.

DESCRIPTION OF SYMBOLS 100 Cassette stand 110 Atmospheric transfer chamber 120 Lock chamber 130 Vacuum transfer chamber 140 Etching chamber 150 Ashing chamber 200 Discharge unit 201 Radio wave source 202 Auto tuner 203 Waveguide 204 Coil 210 Processing chamber 211 Electrode unit 220 Exhaust unit 221 Chamber 222 Gate valve 223 Vacuum pump 300 Upper chamber 310 Lower chamber 320 Coil lifting device 330 Chamber lifting device 340 O-ring seal part 410 Gate 420 Partially removable cover 430 Replaceable cover 440 Heater 450 Gate valve container 600 Gate valve (one on one gate side)
601 Gate 1
602 Gate 2
603 Gate valve (4 on each side of gate)
604 gate 605 gate (top)

Claims (10)

A vacuum processing chamber; an exhaust means for evacuating the vacuum processing chamber; a valve for controlling the pressure in the vacuum processing chamber; a mounting electrode in the vacuum processing chamber for mounting a substrate to be processed; In a vacuum processing apparatus comprising:
The exhaust means is disposed below the mounting electrode, and coaxially exhausts the vacuum processing chamber,
The vacuum processing apparatus, wherein the valve is a gate valve. The vacuum processing apparatus according to claim 1, wherein
The vacuum processing chamber includes a chamber having a two-part structure in which a cylindrical chamber upper portion and a chamber lower portion are fitted and movable in the axial direction.
The vacuum processing apparatus, wherein the gate valve includes a gate that can be opened and closed left and right about an axis of the vacuum processing chamber that is coaxially exhausted by the cylindrical chamber. The vacuum processing apparatus according to claim 2, wherein
The upper part and the lower part of the cylindrical chamber are fitted through a plurality of O-ring seals so as to be movable in the axial direction. A vacuum processing apparatus comprising: The vacuum processing apparatus according to claim 2, wherein
The vacuum processing apparatus, wherein the gate valve includes a maintenance cover. The vacuum processing apparatus according to claim 4, wherein
The vacuum processing apparatus, wherein the maintenance cover includes a partially removable cover provided on the gate valve and a replaceable cover provided on a surface of the gate. The vacuum processing apparatus according to claim 2, wherein
A gate that can be opened and closed to the left and right about the axis of the vacuum processing chamber is formed by connecting a plurality of gates, and when the gate valve is 100% open, the plurality of gates overlap each other in the vertical direction. The vacuum processing apparatus is characterized in that when the gate valve is closed, the opening of the gate valve is closed by controlling the movement of the uppermost gate. The vacuum processing apparatus according to claim 2, wherein
The vacuum processing apparatus, wherein the gate of the gate valve includes a heater. The vacuum processing apparatus according to any one of claims 1 to 7,
The vacuum processing apparatus is a plasma processing apparatus. The vacuum processing apparatus according to any one of claims 1 to 7,
The vacuum processing apparatus is an LCD etching apparatus. The vacuum processing apparatus according to any one of claims 1 to 7,
The vacuum processing apparatus is a plasma CVD apparatus.

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