JP2012104488A - Plasma processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly exhaust air from a plasma processing space.SOLUTION: The plasma processing device comprises: a vacuum chamber 2 surrounding a plasma processing space; a vacuum pump 50 having a suction port 51a communicated and connected with an opening 2a penetrating through a wall from outside; and a substrate support body 12 which is faced to the plasma processing space and on which the substrate can be located. The substrate support body 12 is fastened to the vacuum chamber via the vacuum pump 50. Also, its supporting leg 12a passes through a center of the opening 2a, and serves as a spindle 52 of the vacuum pump 50 as well. Furthermore, the spindle 52 is made into a hollow lever body. Thereby, an exhaust path from the plasma processing space to the opening is identical around the substrate support body, and identity is maintained at the opening, so that the air is exhausted uniformly. The device is made compact.

Description

  The present invention relates to a plasma processing apparatus (plasma reactor) such as a plasma film forming apparatus or a plasma etching apparatus, and in a high-precision manufacturing process such as an IC (semiconductor device), an LCD (liquid crystal display panel), or a PDP (plasma display panel). The present invention relates to a plasma processing apparatus suitable for performing plasma processing, that is, processing based on a plasma reaction, on a substrate or the like as a processing target.

  A plasma processing apparatus for a substrate such as a silicon wafer generates or introduces plasma into a plasma processing space formed in a vacuum chamber and introduces a predetermined processing gas into the plasma processing space. A plasma reaction is performed in the processing space, and thereby a surface treatment such as film formation or etching is performed on the substrate in the plasma processing space. 5A is a typical example of such a plasma reactor, and the parallel plate apparatus shown in FIG. 5B is a parallel plate apparatus. This is an improved example.

  The apparatus shown in FIG. 5A includes a vacuum chamber in which a vacuum chamber lid 3 is attached on a vacuum chamber main body 2 so as to be openable and closable. Therefore, a horizontally placed cathode portion 12 is provided in the center of the vacuum chamber main body 2, and the upper surface of the cathode portion 12 is formed flat and an insulating film is stretched thereon to mount the substrate 1. It is possible to keep it. Such a cathode portion 12 serves as a lower electrode to which high frequency power is applied from an RF power source 31 and a substrate support on which the substrate 1 can be mounted facing the plasma processing space 13 surrounded by a vacuum chamber. It has become. A cylindrical lower support 12a is provided in the center of the inner bottom of the vacuum chamber main body 2 so as to penetrate therethrough, and the cathode portion 12 is fixedly supported on the upper end of the lower support 12a. In addition, an anode portion 11 as an upper electrode is suspended from the vacuum chamber lid portion 3 by a cylindrical upper support 11a at approximately the center of the vacuum chamber lid portion 3 and above the cathode portion 12. Further, the processing gas A necessary for the plasma processing is supplied to the plasma processing space 13 through the anode portion 11 and the like.

  In the vacuum chamber main body 2, an opening 2a is formed through the chamber wall so as to suck out the gas in the vacuum chamber and maintain an appropriate degree of vacuum. In addition, a variable valve 4 and a vacuum pump 5 such as a turbo pump are connected to an outer wall surface of the chamber surrounding the opening 2a through a suitable seal ring in order. As a result, the vacuum pump 5 has the suction port indirectly connected to the opening 2a from the outside. The variable valve 4 in between is provided with a motor or the like that variably drives the valve opening, and functions as a variable throttle of the passing fluid that can be remotely controlled by controlling this with an electric signal. Then, the vacuum pressure in the vacuum chamber is detected by the vacuum pressure gauge 4b attached to the pressure introducing hole 2b formed through the vacuum chamber, and PID control is performed based on the difference between the detected value and a predetermined set target value. When the control signal is generated and output by the circuit 4c, the throttle amount by the variable valve 4 is variably driven according to the control signal. Such a vacuum pressure gauge 4b is used as a pressure detector, a PID control circuit 4c is used as a pressure control circuit, and a variable valve 4 is used as a pressure control mechanism to automatically control the vacuum pressure in the vacuum chamber to a set pressure. The

  In order to improve the pressure uniformity of plasma and gas in such a vacuum chamber, it is common to provide a labyrinth or baffle plate between the plasma processing space 13 and the suction / exhaust through-opening 2a. On the other hand, the apparatus of FIG. 5B is provided with a movable wall 6 that vertically surrounds the periphery of the cathode portion 12 instead of the variable valve 4 in order to achieve improvement in pressure controllability and uniformity. Along with the movable wall 6, a groove 6 a or a bowl-shaped stop 6 b is also formed (see Japanese Patent Application Laid-Open No. 2000-58298).

  However, in such a conventional plasma processing apparatus, the shape and length differ depending on where the exhaust path from the plasma processing space to the suction exhaust through-opening passes around the substrate support passes through the side of the substrate support. Therefore, the difference in the degree of influence on the uniformity is mitigated by the above-mentioned method, and the pressure uniformity is improved as it is, but the complete non-uniformity cannot be eliminated. . Therefore, in order to further improve the pressure uniformity and to achieve this by a relatively simple method, the exhaust path from the plasma processing space to the suction exhaust through-opening is the same everywhere around the substrate support. Thus, it is a technical subject to devise the structure of the vacuum chamber including the vacuum pump.

  The present invention has been made to solve such a problem, and an object thereof is to realize a plasma processing apparatus that uniformly exhausts air from a plasma processing space.

  About the 1st thru | or 4th solution means invented in order to solve such a subject, the structure and effect are demonstrated below.

  [First Solution] The plasma processing apparatus according to the first solution is sucked from the outside with respect to the vacuum chamber surrounding the plasma processing space and the opening penetrating the wall, as described in claim 1 at the beginning of the application. A plasma processing apparatus comprising: a vacuum pump having a mouth connected to the substrate; and a substrate support capable of mounting a substrate facing the plasma processing space, wherein the substrate support is connected to the vacuum chamber via the vacuum pump. It has been fixed to.

  In such a plasma processing apparatus of the first solving means, since the plasma processing space, the substrate support, and the suction exhaust through-openings are arranged in series, the exhaust path from the plasma processing space to the suction exhaust through-opening Will be the same everywhere around the substrate support. Moreover, since it is not restricted by the presence or absence of a movable wall body or a baffle, there are almost no restrictions on the exhaust path, and the structure can be easily simplified. Therefore, according to the present invention, it is possible to realize a plasma processing apparatus that uniformly exhausts air from the plasma processing space.

  [Second Solution] The plasma processing apparatus of the second solution is the plasma processing apparatus of the first solution, as described in claim 2 at the beginning of the application, and supports the substrate support. The supporting legs extend from the vacuum pump and pass through the center of the opening to reach the substrate support.

  In such a plasma processing apparatus of the second solution, the support leg necessary for supporting the substrate support passes through the center of the suction exhaust through opening. Thus, the exhaust path from the plasma processing space to the suction exhaust through-opening is the same for the entire periphery of the support leg at the opening. Therefore, according to the present invention, it is possible to realize a plasma processing apparatus that exhausts air from the plasma processing space more uniformly.

  [Third Solving Means] The plasma processing apparatus of the third solving means is the plasma processing apparatus of the second solving means, as described in claim 3 at the beginning of the application, wherein the support legs It also serves as a support shaft that rotatably supports the exhaust rotary member in the vacuum pump.

  In such a plasma processing apparatus of the third solving means, since the support leg and the support shaft are integrated, the apparatus is simplified and reduced in size. Therefore, according to the present invention, it is possible to realize a compact plasma processing apparatus that exhausts air from the plasma processing space more uniformly.

  [Fourth Solution] The plasma processing apparatus of the fourth solution is the plasma processing apparatus of the third solution, as described in claim 4 at the beginning of the application, wherein the support shaft is hollow. It is made of a box.

  In such a plasma processing apparatus of the fourth solution, it is possible to break the vacuum of the plasma processing space by attaching wiring and piping from the outside to the substrate support by passing through the support shaft. It can be done easily. Therefore, according to the present invention, it is possible to easily realize a compact plasma processing apparatus that more uniformly exhausts air from the plasma processing space.

  As is clear from the above description, in the plasma processing apparatus of the first solving means of the present invention, the plasma processing space, the substrate support, and the suction exhaust through openings are arranged in series. There is an advantageous effect that a plasma processing apparatus that uniformly exhausts air from the plasma processing space can be realized.

  Further, in the plasma processing apparatus of the second solving means of the present invention, the exhaust path from the plasma processing space to the through-exhaust opening for suction and exhaust is maintained even at the opening. There is an advantageous effect that a plasma processing apparatus that exhausts air from the plasma processing space more uniformly can be realized.

  Further, in the plasma processing apparatus according to the third solving means of the present invention, the support leg and the support shaft are integrated so that the plasma processing space can be more uniformly exhausted from the plasma processing space. There is an advantageous effect that the apparatus can be realized compactly.

  Further, in the plasma processing apparatus of the fourth solving means of the present invention, in such a plasma processing apparatus of the fourth solving means, wiring and piping can be performed through the support shaft. Thus, there is an advantageous effect that a compact plasma processing apparatus that more uniformly exhausts air from the plasma processing space can be easily realized.

About the 1st Example of the plasma processing apparatus of this invention, the detailed structure of the lower electrode and vacuum pump which are the principal parts is shown, (a) is an external appearance perspective view, (b) is a longitudinal cross-sectional view. It is a longitudinal cross-sectional schematic diagram containing the whole chamber. It is a longitudinal cross-sectional view of the principal part about 2nd Example of the plasma processing apparatus of this invention. FIG. 6 is a longitudinal sectional view of the main part of a third embodiment of the plasma processing apparatus of the present invention, in which (a) and (b) are both; About the conventional plasma processing apparatus, (a), (b) is a longitudinal cross-sectional schematic diagram.

  Specific embodiments for implementing the plasma processing apparatus of the present invention achieved by such a solution will be described with reference to the following first and second embodiments. The first embodiment shown in FIGS. 1 and 2 embodies all of the above-described solving means. The second embodiment shown in FIG. 3 and the third embodiment shown in FIG. This is a modified example. In the drawings, the same reference numerals are given to the same components as those in the prior art, and therefore, repeated explanations are omitted. Hereinafter, the differences from the prior art will be mainly described.

First embodiment

  A specific configuration of the plasma processing apparatus according to the first embodiment of the present invention will be described with reference to the drawings. 1A and 1B show the detailed structure of a lower electrode and a vacuum pump as main parts, where FIG. 1A is an external perspective view, and FIG. 1B is a longitudinal sectional view. FIG. 2 is a schematic longitudinal sectional view including the entire chamber, and corresponds to FIG. 5A of the conventional example.

  This plasma processing apparatus is different from the conventional apparatus of FIG. 5A in that the suction / exhaust through-opening 2a is located immediately below the cathode portion 12 (substrate support) in the bottom wall of the vacuum chamber main body 2. The turbo pump 50 described later is adopted for the vacuum pump 5 and the suction port 51a is directly connected to the opening 2a. The support shaft 52 and the lower support 12a ( (Supporting legs) is an integral part. Thereby, the plasma processing space 13, the cathode portion 12, the opening 2a, and the turbo pump 50 are arranged in a vertical row and are rotationally symmetric with respect to the vertical axis.

  The turbo pump 50 is different from a general turbo pump in that a hollow housing is employed for a support shaft 52 that rotatably supports a sleeve 53 and a fin 54 that are exhaust rotary members, and its support. The shaft 52 extends upward from the inner bottom of the pump main body 51 and further reaches the cathode portion 12 through the center of the opening 2a. As a result, the support shaft 52 also serves as the lower support 12a, and the cathode portion 12 is fixed to the vacuum chamber main body 2 via the turbo pump 50.

  The hole 52a penetrating the shaft core of the support shaft 52 passes through the protective member 12b of the cathode portion 12 at the upper end portion and passes through the bottom wall of the pump body 51 at the lower end portion and communicates with the atmosphere. The through hole 52 a is also used for the wiring of the RF cable 32. That is, the RF cable 32 extending from the external RF power source 31 reaches the cathode portion 12 through the through hole 52a and is connected to the electrode member 12c. Although illustration is omitted, if necessary, the piping for feeding the refrigerant is also easily installed using the through hole 52a.

  Since the suction port 51a of the turbo pump 50 is directly connected to the opening 2a, a gate valve 40 is introduced in place of the variable valve 4, which is connected to the discharge port 51b of the turbo pump 50 and is connected to the pump body 51. By controlling the speed of the fin rotation driving electric motor including the fixed stator 55 and the rotor 56 mounted on the sleeve 53 by the inverter 57, the pressure control by the PID control circuit 4c is performed. Yes. In addition, the operation of the PID control circuit 4c and the inverter 57 and the opening and closing of the gate valve 40 are sequence-controlled according to the recipe set in the controller 41 together with the output of the RF power supply 31 and the flow rate of the processing gas A. Yes.

  The use mode and operation of the plasma processing apparatus of the first embodiment will be described. The general operation and the like of the plasma processing apparatus are disclosed in JP-A-10-335315 and JP-A-2000-58298. Therefore, here, the description will focus on vacuuming (suction / exhaust operation) and pressure control, which are the main differences from the prior art.

  Under the sequence control of the controller 41, the horizontal substrate 1 is carried into the vacuum chamber (2 + 3) from the side, and the substrate 1 is placed on the upper surface of the cathode portion 12. Then, at the same time as the substrate loading port (not shown) is closed, the gate valve 40 is opened, and then the vacuum pumping is performed by the turbo pump 50. At this time, since the variable valve 4 does not exist, the vacuum chamber is quickly evacuated.

  That is, although the target value of the vacuum pressure is set in the PID control circuit 4c, initially, the measured value of the vacuum pressure gauge 4b is far from the measured value, so that the motor 55 + 56 and the fin 54 are rotated at high speed by the inverter 57 so as to reduce the difference. As a result, exhaust is rapidly performed from the discharge port 51b of the turbo pump 50. Accordingly, the gas in the vacuum chamber is also sucked out from the suction port 51a of the turbo pump 50 and the suction / exhaust through opening 2a of the vacuum chamber.

  At that time, the gas in the plasma processing space 13 turns downward from the side periphery of the cathode portion 12, then turns downward along the support shaft 52, passes through the opening 2 a, and is discharged by the turbo pump 50. In the middle of the flow path, there is no variable valve 4 for narrowing the flow path, and there is nothing that extends directly from the cathode portion 12 to the vacuum chamber main body 2 and tears the flow path. Since the 13 gases are decompressed almost uniformly from anywhere on the edge, the uniformity of the pressure distribution is improved accordingly.

  When the pressure in the plasma processing space 13 reaches or sufficiently approaches the target pressure, the rotational speeds of the motors 55 + 56 and the fins 54 are reduced by the control of the PID control circuit 4c and the inverter 57, and thereafter the target pressure is maintained. The rotational speed is increased or decreased. Since there is nothing that obstructs the flow in the discharge path from the plasma processing space 13 to the turbo pump 50, pressure control is excellent in both responsiveness and stability even if the motor rotation speed is variable.

  In this state, plasma is formed or introduced into the plasma processing space 13, and the processing gas A is supplied. Further, if necessary for exciting the plasma or imparting anisotropy, a high frequency is also applied from the RF power source 31. Then, the substrate 1 is subjected to the plasma treatment. Even in this state, the plasma and the by-product gas are discharged with good uniformity. Thus, in this plasma processing apparatus, the pressure in the plasma processing space 13 can be quickly changed when variably controlled. In addition, the uniformity of the pressure can be increased.

Second embodiment

  The plasma processing apparatus of the present invention, whose longitudinal sectional view is shown in FIG. 3, is different from that of the first embodiment described above in that the installation location of the electric motor 55 + 56 is changed. Specifically, the mounting location of the stator 55 is moved from the inner surface of the pump body 51 to the outer peripheral surface of the support shaft 52, and the mounting location of the rotor 56 is transferred from the outer peripheral surface of the sleeve 53 to the inner peripheral surface. .

  In this case, if the height of the turbo pump 50, that is, the length in the axial direction is the same, the number of stages of the fins 54 can be increased, and if the number of stages of the fins 54 is kept the same, the height of the turbo pump 50 is decreased. can do.

Third embodiment

  The difference between the plasma processing apparatus of the present invention whose longitudinal section is shown in FIG. 4 and that of the first embodiment described above corresponds to the variable valve 4 shown in FIG. The variable valve mechanisms 61 to 46 are provided in the vacuum chamber 2. Specifically, a ring-shaped / perforated disk-shaped movable valve body 61 is connected between the inner wall of the vacuum chamber main body 2 and the lower surface of the cathode portion 12, and one end is connected to the other, and the other end is the vacuum chamber main body. A bellows 62 connected to the inner wall of the two is provided so as to surround the support shaft 52 that extends into the vacuum chamber 2 through the opening 2a, that is, the lower support 12a. A rod 64 extending from the movable valve body 61 is connected to a rod 64 that is driven forward and backward by an electric motor 65 outside the chamber, so that the movable valve body 61 can move up and down.

  In this case, when the motor 65 is operated to raise the movable valve body 61 to the upper limit, that is, the lower surface of the cathode portion 12, in that state (see FIG. 4A), the opening 2a is closed. Then, when the movable valve body 61 is lowered by operating the motor 65 (see FIG. 4B), an annular gap 66 is formed between the cathode portion 12 and the movable valve body 61. By variably controlling the gap 66 according to the detected pressure in the vacuum chamber, the pressure can be controlled without the inverter 57. Moreover, various pressure controls can be performed by using the inverter 57 together. In this case, the movable valve body 61 may move on the inner wall side of the vacuum chamber main body 2 to adjust the gap with the movable valve body 61, and the rod 64 may be disposed inside the bellows 62. Thus, the rod 63 may be omitted.

Other

  In each of the above embodiments, the parallel plate type plasma processing apparatus has been described, but the application of the present invention is not limited to the parallel plate type. The cathode part 12 and the anode part 11 may not be electrodes. It is sufficient that the substrate 1 can be mounted facing the plasma processing space 13. Further, the substrate 1 is not limited to a disk-like and hard one like a silicon wafer, but may be a square plate like an LCD panel, or may be soft like a plastic film. Further, if necessary for taking them in and out, an appropriate open / close gate, a lifter and the like are also attached to the vacuum chamber.

1 Substrate (plate-like workpiece, film, wafer)
2 Vacuum chamber body (vacuum chamber)
2a Opening (Vacuum pump attachment port, suction exhaust through opening, exhaust passage)
2b Induction hole (Induction path)
3 Vacuum chamber lid (vacuum chamber)
4 Variable valves (flow control, variable throttle, pressure control mechanism, pressure control means)
4b Vacuum pressure gauge (pressure detector, pressure control means)
4c PID control circuit (pressure control circuit, pressure control means)
5 Vacuum pump (exhaust pump)
6 Movable wall (flow control, variable throttle)
6a Groove (pressure buffer space, leak pressure buffer means, equal pressure space)
6b Wrinkle-shaped drawing (thin ring, overhanging part, drawing part, hook-shaped member)
11 Anode (plasma space formation mechanism, upper electrode)
11a Upper support 12 Cathode part (plasma space formation mechanism, lower electrode part, substrate support)
12a Lower support (support leg, lower electrode support)
12b Protection member (insulator)
12c Electrode member (good conductor)
13 Plasma processing space (plasma formation space, plasma introduction space)
31 RF power supply (high frequency application circuit)
32 RF cable (high frequency application circuit)
40 Gate valve (open / close valve)
41 Controller (Sequence control means)
50 Turbo pump (turbo molecular pump, vacuum pump)
51 Pump body (outer cylinder)
51a Suction port 51b Discharge port 52 Support shaft (fixed member, hollow rod, lower electrode supporting leg combined member)
52a Through hole (hollow part)
53 Sleeve (Rotating cylinder, exhaust rotating member)
54 Fins (blade member, wing member, exhaust rotary member)
55 Stator (coil part, fixed part, electric motor)
56 Rotor (magnet part, rotating part, electric motor)
57 Inverter (frequency conversion, rotation speed control, pressure control means)

Claims (4)

  A vacuum chamber surrounding the plasma processing space; a vacuum pump having a suction port communicating with the opening through the wall; and a substrate support capable of mounting the substrate facing the plasma processing space. In the plasma processing apparatus, the substrate support is fixed to the vacuum chamber via the vacuum pump.   The plasma processing apparatus according to claim 1, wherein a support leg that supports the substrate support extends from the vacuum pump, passes through a center of the opening, and reaches the substrate support.   The plasma processing apparatus according to claim 2, wherein the support leg is a support shaft that rotatably supports an exhaust rotary member in the vacuum pump.   The plasma processing apparatus according to claim 3, wherein the support shaft is a hollow casing.

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