JP2009246172A - Plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parallel flat plate type plasma treatment device that suppresses abnormal discharge between a cathode electrode and a mesh member that covers an exhaust port. <P>SOLUTION: In the plasma treatment device 2, which applies high-frequency electric power between an anode electrode (gas shower head 40) and the cathode electrode (placement table 3), which are provided oppositely in a treatment container 20 to change a processing gas into plasma, and performs plasma treatment on a workpiece S; a conductive member (mesh member 51) having an opening is disposed at a periphery of the cathode electrode and covers the exhaust port for discharging the treatment gas; and a dielectric 52 is interposed between the conductive member and a conductive wall portion of the treatment container 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus that converts a processing gas into plasma using high-frequency power and performs processing such as etching on an object to be processed using the plasma.

  In the manufacturing process of a flat panel such as a semiconductor device or a liquid crystal display device, a plasma etching apparatus or a plasma CVD film forming apparatus is used to perform a process such as an etching process or a film forming process on a substrate to be processed such as a semiconductor wafer or a glass substrate. Or the like is used.

  The plasma processing apparatus shown in FIG. 8 shows a configuration example of a plasma etching apparatus that performs an etching process on a thin film formed on a glass substrate for an FPD (Flat Panel Display), for example. In this plasma etching apparatus, an upper electrode 12 that also serves as a gas shower head serving as a gas supply unit is provided in a grounded processing vessel 10 made of, for example, aluminum, and the substrate S is opposed to the upper electrode 12. It is comprised as a parallel plate type plasma processing apparatus provided with the lower electrode 11 which also serves as a mounting table. The upper electrode 12 is connected to the processing vessel 10 and configured as an anode electrode, while the lower electrode 11 is in a state of being sufficiently electrically floated with respect to the processing vessel 10 by the insulating material 14, and a matching circuit (not shown). The cathode electrode is connected to the high-frequency power supply 15 via the (matching circuit). Further, as shown in FIG. 8, the periphery and side surfaces of the surface of the lower electrode 11 are covered with a shield ring 18 made of an insulator such as ceramics for uniformly forming plasma above the lower electrode 11. There is also.

  FIG. 9 shows an equivalent circuit of a conductive path for high-frequency current in this plasma etching apparatus. When processing gas is supplied into the processing vessel 10 and high-frequency power is applied between the upper electrode 12 and the lower electrode 11 by the high-frequency power source 15 to convert the processing gas into plasma, the lower electrode 11 and the upper electrode 12 are Since the capacitive coupling C1 is formed, the high-frequency current from the high-frequency power source 15 flows through the path of the lower electrode 11 → plasma → the upper electrode 12 → the wall of the processing vessel 10 → the ground, and uses this plasmaized processing gas. Then, the substrate S placed on the lower electrode 11 is etched. More specifically, the high-frequency current returns from the wall of the processing vessel 10 to the ground of the high-frequency power supply 15 through a matching circuit housing (matching box) (not shown).

  By the way, for example, the substrate S for FPD, which is a processing target of the apparatus, tends to increase in size, and accordingly, the processing container 10 also increases in size. When the processing container 10 is enlarged, the inductance component of the processing container 10 is increased, and the impedance of the high-frequency current path is increased. For this reason, the wall portion of the processing vessel 10 that is closer to the cathode electrode than the anode electrode looks like the anode electrode when viewed from the cathode electrode, and the two members are easily capacitively coupled. Therefore, a technique is known in which an impedance adjustment mechanism is interposed in the current path between the anode electrode and the processing container to relatively reduce the impedance (Patent Document 1). However, when the lower electrode 11 is a cathode electrode as in the above-described plasma etching apparatus, capacitive coupling is still likely to occur between the side and bottom surfaces of the processing vessel 10 around the lower electrode 11 and the lower electrode 11. It is in a state.

  Here, an exhaust path 16 for exhausting the gas after processing the substrate S is provided on the bottom surface of the processing container 10, and foreign substances fall into the exhaust path 16 at the exhaust port of the exhaust path 16. A protective mesh member 17 is provided for preventing intrusion and suppressing intrusion and generation of plasma into the exhaust passage 16. As the mesh member 17, a metal material is used from the viewpoint of workability and strength. In order to form a uniform plasma, the mesh member 17 is in contact with the processing vessel 10 based on a preconceived design philosophy that it is preferable that the surroundings have the same potential as viewed from the lower electrode 11. However, it was at the same potential as the processing container 10.

For this reason, the mesh member 17 provided at a position near the lower electrode 11 at the bottom of the processing vessel 10 is an anode electrode closer to the upper electrode 12 when viewed from the lower electrode 11, and the lower electrode 11 and the mesh member 17. Capacitive coupling (indicated as C2 in FIG. 9) is formed between the two and, for example, glow discharge is likely to occur. The inventors of the present invention have typical conditions for the occurrence of this phenomenon in which the pressure in the processing container 11 is in the range of 0.67 Pa to 27 Pa (5 mtorr to 200 mtorr), and the processing gas is a halogen such as chlorine gas. A negative gas typified by a system gas, CF ₄ gas, O ₂ gas, etc., that is, a plasma in which molecules constituting the gas adhere to electrons to generate many negative ions, and these negative ions are more than electrons. In addition, it is confirmed that the substrate S is large in size with one side of the substrate S exceeding 1 m and the lower electrode 11 is provided on the mounting table as described above.

  In addition, the vicinity of the exhaust port of the exhaust passage 16 through which the gas in the processing vessel 10 flows is in various pressure atmospheres depending on the process conditions such as the gas flow rate and pressure, but in general, the minimum required for generating plasma between the electrodes. Since the voltage is a function of the pressure in the space formed between the electrodes, in combination with the above-described factors, glow discharge occurs between the lower electrode 11 serving as the cathode electrode and particularly the mesh member 17. Cheap.

  In this way, when unnecessary capacitive coupling is formed between the lower electrode 11 and the mesh member 17 and a strong glow discharge is locally generated, the lower electrode 11 and the upper electrode 12, which are the original plasma generation spaces, are formed. For example, so-called arcing in which an arc-like abnormal discharge is generated on the surface of the member in the processing vessel 10 or the substrate S is induced to damage or wear these members or the substrate S. There is a possibility that the in-plane uniformity of the processing of the substrate S is deteriorated due to the generation of a biased plasma.

JP 2005-340760; paragraph 0027, FIG.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress the occurrence of abnormal discharge between the cathode electrode and the mesh member covering the exhaust port in the parallel plate type plasma processing apparatus. It is to provide a plasma processing apparatus.

The plasma processing apparatus according to the present invention is a plasma for applying a high-frequency power between an anode electrode and a cathode electrode provided opposite to each other in a processing container to convert the processing gas into plasma and performing plasma processing on the object to be processed. In the processing device,
An exhaust port disposed around the cathode electrode and exhausting the processing gas;
A conductive member that covers the exhaust port and has an opening through which the processing gas exhausted to the exhaust port flows;
And a dielectric provided between the conductive member and the conductive wall portion of the processing container.
The conductive member is preferably a metal, for example, and the dielectric is preferably ceramic, and the conductive member is preferably mesh-shaped.

  Further, the first conductive member that covers the exhaust port, is provided in the peripheral portion of the exhaust port, and covers the upper space of the first conductive member, and the first conductive member, And a second conductive member provided apart from each other, and the conductive member may be configured as the second conductive member. Also in this case, it is preferable that the first conductive member and the second conductive member are metal, and the dielectric is ceramic. When the first conductive member and the second conductive member have a mesh shape, the first conductive member has a mesh shape, and the second conductive member has a flat plate shape. Some cases are preferred. Furthermore, a second dielectric provided between the first conductive member and the conductive wall portion of the processing container may be provided.

In each of the plasma processing apparatuses described above, the cathode electrode and the exhaust port are preferably provided in a lower part of the processing container, and the plasma processing apparatus has a corner having an area of 4.0 m ² or more. It is suitable when the mold substrate and the processing gas are a negative gas, and the pressure atmosphere in which the plasma processing is performed is in the range of 0.67 Pa to 27 Pa.

  According to the present invention, in the parallel plate type plasma processing apparatus, the dielectric is provided between the mesh member covering the exhaust port provided in the processing container and the conductive wall portion of the processing container. As a result, the impedance of an abnormal path from the cathode electrode provided with the mounting table to the processing vessel via the mesh member increases, so that the capacitive coupling between the cathode electrode and the mesh member becomes difficult, and abnormal discharge is suppressed. For this reason, generation | occurrence | production of arcing is suppressed and the damage and wear of the member in a processing container and a board | substrate can be suppressed.

  Hereinafter, an embodiment in which a plasma processing apparatus of the present invention is applied to an FPD substrate etching processing apparatus 2 will be described with reference to FIGS. The etching processing apparatus 2 includes a processing container 20 which is a vacuum chamber for performing an etching process on an object to be processed, for example, a substrate S which is an FPD substrate. The processing container 20 is grounded via a matching box casing 64 which will be described later.

  The substrate S is a square glass substrate having a side length of more than 1 m, and the processing container 20 has a horizontal cross section of, for example, one side of 3.5 m and the other side of about 3.0 m corresponding to the shape of the substrate S. It is comprised by the magnitude | size and is comprised by the electroconductive material with favorable heat conductivity, such as aluminum, for example. A loading / unloading port 22 for loading the substrate S into the processing chamber 20 is formed in one side wall portion 21 of the processing chamber 20, and the loading / unloading port 22 is configured to be opened and closed by a gate valve 23.

  Inside the processing container 20, a mounting table 3 for mounting the substrate S is disposed on the upper surface thereof. The mounting table 3 is electrically connected to the first high-frequency power supply unit 311 for generating plasma and the second high-frequency power supply unit 312 for drawing ions in the plasma via matching circuits 62 and 63, respectively. It serves as a cathode electrode that generates plasma in the container 20 and draws ions in the plasma to the surface of the substrate S. The matching circuits 62 and 63 are housed in a conductive casing 64 which is a matching box, and the casing 64 is connected to the bottom wall of the processing vessel 20 via a conductive conduit member 65. . The casing 64 is connected to the ground side of the first and second high-frequency power supply units 311 and 312, so that the processing container 20 is grounded via the casing 64.

  The mounting table 3 is disposed on the bottom surface of the processing container 20 via a dielectric 32, whereby the mounting table 3, which is a lower electrode, is in an electrically floating state from the processing container 20. Further, the peripheral edge and the side surface of the surface of the mounting table 3 are covered with a shield ring 33 made of a ceramic material for forming plasma uniformly above the mounting table 3.

  Further, the mounting table 3 is provided with lifting / lowering pins 34 for transferring the substrate S between the transfer device (not shown) outside the etching processing apparatus 2 and the mounting table 3. The elevating pins 34 are configured so as to protrude and retract from the surface of the mounting table 3 by the elevating mechanism 35, and are provided on the surface of the mounting table 3 and the position where the substrate S is transferred to and from the external transfer means. The board | substrate S can be raised / lowered between the positions where S is mounted.

  On the other hand, a flat plate-like upper electrode 4 that is an anode electrode is provided above the mounting table 3 inside the processing container 20 so as to face the surface of the mounting table 3. The upper electrode 4 is a square plate. It is supported by the upper electrode base 41 having a shape. The upper electrode 4 and the upper electrode base 41 are made of, for example, aluminum. The upper surface of the upper electrode base 41 is fixed to the ceiling portion of the processing container 20 via a dielectric 45, and the upper electrode 4 and its base 41 are connected to the processing container via the impedance adjusting mechanism 6 and the conductive cover body 61. 20 is electrically connected.

  The impedance adjustment mechanism 6 plays a role of adjusting the impedance from the upper electrode 4 to the processing container 20, and a circuit including a capacitor, for example, a variable capacitance capacitor is used, and the plasma capacitance (C 1) and the processing from the upper electrode 4 are performed. The inductance (L) of the path to the lower part of the container 20 is canceled by the capacitance component (C) of the impedance adjustment mechanism 6. Thereby, the impedance adjustment mechanism 6 makes the impedance of the path of the mounting table 3 (lower electrode) → plasma → upper electrode 4 → impedance adjustment mechanism 6 → processing vessel 20 → ground as j (−1 / ωC1 + ωL−1 / ωC), It plays the role of making it smaller than the impedance of the abnormal path described later.

  A space surrounded by the upper electrode base 41 and the upper electrode 4 constitutes a gas diffusion space 42 for the etching gas. Hereinafter, the upper electrode 4 and the upper electrode base 41 are collectively referred to as a gas shower head 40. A processing gas supply path 43 is provided on the ceiling of the processing container 20 so as to be connected to the gas diffusion space 42, and the other end side of the processing gas supply path 43 is interposed via the gas diffusion space 42. And a processing gas supply unit 44 for supplying an etching gas into the processing container 20.

  Here, as shown in FIGS. 1 and 2, a flat baffle plate 25 made of, for example, an aluminum member whose surface is anodized is disposed in the space between the side surface of the mounting table 3 and the side wall portion 21. It is installed. The baffle plate 25 is disposed in a region on the outer side of the four sides of the mounting table 3, and is viewed from a space where plasma is formed between the mounting table 3 and the gas shower head 40. It is arranged at a position that blocks the front. The baffle plate 25 prevents the etching gas supplied to the surface of the substrate S on the mounting table 3 from flowing directly into the exhaust port 241 to suppress the gas flow unevenness, and the etching gas is uniformly distributed over the entire surface of the substrate S. It plays the role of making it flow. As shown in FIG. 2, at the four corners on the outer side of the baffle plate 25, flow holes 251 that are not provided with the baffle plate 25 are opened, and the etching gas supplied into the processing container 20 is It flows to the downstream side through the baffle plate 25.

  As shown in FIGS. 1 to 3, an opening that forms a horizontally long exhaust port 241 is formed on the bottom wall of the processing vessel 20. An exhaust pipe forming the exhaust path 24 is connected to the lower side of the exhaust port, and the upstream end of the exhaust pipe is expanded by the expanding portion 242 to a shape corresponding to the shape of the horizontally long exhaust port 241. In addition, a flange portion formed at the opening edge of the expanded portion 242 is airtightly joined to the lower surface side of the bottom wall of the processing vessel 20. The exhaust ports 241 are provided at a total of eight locations, for example, two locations along the side wall portions 21 on the bottom wall of the processing container 20 between the mounting table 3 and the side wall portions 21. A pressure adjusting mechanism 26 composed of, for example, a butterfly valve is interposed in the downstream exhaust pipe. The exhaust pipe joins on the downstream side of the pressure adjusting mechanism 26 and is connected to the vacuum pump 27 at the downstream end.

  Each exhaust port 241 is covered with a mesh member 51 made of metal such as aluminum, which is a conductive member, as shown in FIGS. 3 and 4A, and as described in the background art, this mesh member. 51 plays a role in suppressing the fall and intrusion of foreign matter into the exhaust passage 24 and further the intrusion and generation of plasma into the exhaust passage 24. In this example, the mesh of the mesh member 51 corresponds to the opening of the conductive member.

  As shown in FIG. 3 and FIG. 4B, the mesh member 51 is connected to the processing container 20 by, for example, a bolt 511 made of a dielectric material made of ceramic, for example, via a small piece of dielectric material 52 made of ceramic, eg, alumina. It is fastened to the bottom wall surface, and is fixed from the bottom wall surface through a gap of, for example, 5 mm to 20 mm. For example, the dielectric member 52 locally supports the mesh member 51 at eight locations around the exhaust port 241, and the dielectric member 52 is interposed between the metal processing vessel 20 and the mesh member 51. It has become.

  As shown in FIG. 1, the etching processing apparatus 2 is connected to a control unit 7. The control unit 7 includes, for example, a computer including a CPU and a storage unit (not shown). The operation of the etching processing apparatus 2, that is, the substrate S is carried into the processing container 20 and loaded on the mounting table 3. A program in which a group of steps (commands) regarding control and the like related to operations from when the placed substrate S is subjected to an etching process to when it is carried out is recorded. This program is stored in a storage medium such as a hard disk, a compact disk, a magnetic optical disk, or a memory card, and installed in the computer therefrom.

  Hereinafter, the operation of the etching processing apparatus 2 according to the present embodiment will be described. First, when the user selects a process recipe for a target etching process with respect to the control unit 7 via an operation unit (not shown), the control unit 7 outputs a control signal to each unit of the etching processing apparatus 2 based on the process recipe. Thus, a predetermined etching process is performed on the substrate S.

  Specifically, first, the gate valve 23 is opened, and the substrate S on which the Al film is formed is carried into the processing container 20 by an external transfer means (not shown), and above the mounting area of the mounting table 3. To the delivery position. Then, the lift pins 34 are raised, the substrate S is transferred from the transfer means to the lift pins 34 at this transfer position, and the lift pins 34 are lowered to place the substrate S on the placement region on the placement table 3. During this time, the transfer means that delivered the substrate S moves out of the processing container 20 and closes the loading / unloading port 22 by the gate valve 23.

Next, an etching gas for etching processing, for example, a halogen-based negative gas such as chlorine gas is discharged from the processing gas supply unit 44 toward the substrate S, and the internal space of the processing container 20 is adjusted to a predetermined pressure. Then, a high frequency power of, for example, 13.56 MHz is supplied from the first high frequency power supply unit 311 for generating plasma to 5.5 kW, and a high frequency power of, for example, 3.2 MHz is supplied from the second high frequency power supply unit 312 for drawing ions into the plasma. An etching process is performed on the substrate S based on the main reaction expressed by the following equation (1) by applying 0.0 kW to the mounting table 3 and using plasma formed in the space above the substrate S.
3Cl ^* + Al → AlCl ₃ (1)

  The flow of the etching gas in the processing container 20 at this time will be described. The etching gas supplied from the gas shower head 40 is converted into plasma while descending between the upper and lower electrodes 4 and 3 and reaches the substrate S. It flows on the surface of the substrate S and the baffle plate 25 and flows into the flow port 251. Then, the air is exhausted from the space below the baffle plate 25 to the exhaust path 24 via each exhaust port 241.

  On the other hand, by converting the etching gas into plasma, the high frequency power is changed from the mounting table (lower electrode) 3 to plasma → the upper electrode 4 (gas shower head 40) → the impedance adjusting mechanism 6 → the processing vessel 20 → the casing 64 which is a matching box. → The first and second high-frequency power supplies 311 and 312 are grounded so to speak. At this time, a mesh member 51 that covers the exhaust port 241 of the exhaust path 24 is provided in the vicinity of the mounting table 3 that is the lower electrode, and the atmosphere around the mesh member 51 is exhausted as described in the background art. As the gas flows toward the exhaust port 241, various pressure atmospheres are formed according to the process recipe. For this reason, there is a possibility that the mesh member 51 may be in a pressure atmosphere in which glow discharge is easily generated between the mesh member 51 and the mounting table 3, but the mesh member 51 that is a conductor visible from the mounting table 3 is supported by the dielectric 52. As a result, the mounting table 3 including the shield ring 33 → plasma → the mesh member 51 → the processing container 20 → the ground between the mesh member 51 and the processing container 20 via the dielectric 52 in an abnormal path. As a result, the capacitance of the abnormal path is increased. As a result, the mesh member 51 is difficult to see on the anode electrode closest to the mounting table 3 that is the cathode electrode, suppresses the occurrence of glow discharge between the mounting table 3 and the mesh member 51, and discharge occurs. However, the degree can be kept small.

  The etching processing apparatus 2 according to the present embodiment has the following effects. In the etching processing apparatus 2 which is a parallel plate type plasma processing apparatus, a dielectric 52 is provided between the mesh member 51 covering the exhaust port 241 provided in the processing container 20 and the conductive processing container 20. . As a result, the impedance of a so-called abnormal path from the cathode electrode provided with the mounting table 3 to the processing vessel 20 via the mesh member 51 becomes large, and the cathode electrode and the mesh member 51 are difficult to capacitively couple, and abnormal discharge is caused. It can be suppressed. For this reason, generation | occurrence | production of arcing is suppressed and the damage and wear of the member in the processing container 20 and the board | substrate S can be suppressed. In addition, it is possible to suppress the plasma bias due to destabilization of capacitive coupling between the mounting table 3 and the upper electrode 4 and perform the substrate S processing with high in-plane uniformity.

Further, this effect will be described in detail. In the case of a large substrate S having a substrate area of 1 m ² or more, particularly 4 m ² or more, it is easy to perform capacitive coupling between the cathode electrode and the processing vessel 20 and surrounding members. An impedance adjusting mechanism 6 is interposed between the anode electrode and the processing container 20. However, the vicinity of the exhaust port 241 of such a processing vessel 20 has various pressure atmospheres depending on the process recipe. In particular, glow discharge is likely to occur in a pressure range of 0.67 Pa to 27 Pa (5 mtorr to 200 mtorr). When a negative gas such as a halogen-based gas such as chlorine gas is used as a processing gas, the gas dissociation is large, so that a glow discharge is more likely to occur. In the etching processing apparatus 2 that satisfies these conditions, The structure in which the mesh member 51 is electrically floated with respect to the processing container 20 is extremely effective in performing processing with high in-plane uniformity on the large substrate S.

  In addition, in the above-described embodiment, the plasma processing apparatus 2 of the type provided with the impedance adjustment mechanism 6 is exemplified. However, the present invention is also applied to a plasma processing apparatus of a type not provided with such an impedance adjustment mechanism 6. By doing so, it is possible to suppress the occurrence of abnormal discharge by increasing the impedance of the abnormal path described above. However, the provision of the impedance adjustment mechanism 6 facilitates adjustment to reduce the impedance of the normal path relative to the impedance of the abnormal path, and the dielectric 52 is disposed between the mesh member 51 and the processing container 20. As a result, the effect of increasing the effectiveness of the present invention can be obtained.

  Here, the configurations of the mesh member and the dielectric are not limited to those illustrated in FIGS. 4A and 4B. For example, as shown in FIGS. 5 (a) and 5 (b), a dielectric 52a surrounding the entire circumference of the exhaust port 241 of the exhaust path 24 is provided, and for example, a flange portion 512 adapted to the shape of the dielectric 52a is provided. The mesh member 51a may be supported. Since the gap between the bottom wall surface of the processing container 20 and the mesh member 51a is filled with the dielectric 52a, it is possible to prevent foreign matter from falling into and entering the exhaust path 24 through this gap.

  Further, as shown in FIG. 6, in a state where the metal mesh member 53 is in contact with the peripheral portion of the exhaust port 241, the metal mesh member 53 is fixed with, for example, a metal bolt and further protruded so as to cover the space above the mesh member 53. A second mesh member 51b formed in a shape and spaced apart from the mesh member 53 may be provided, and the second mesh member 51b may be fixed on the dielectric 52. In this example, the second mesh member 51b corresponds to the second conductive member in the claims, and the mesh member 53 corresponds to the first conductive member in the claims. In this case, since the second mesh member 51b is added to the processing container 20 including the existing mesh member 53 that is installed in contact with the peripheral portion of the exhaust port 241, the apparatus can be used. There is an advantage that remodeling is easy. In this example, it is needless to say that a second dielectric may be interposed between the mesh member 53 and the processing container 20.

  In addition, as another example in which the first conductive member and the second conductive member are provided, for example, the baffle plate 25 is a second conductive member, and the baffle plate is formed on the side wall surface of the processing vessel 20 via a dielectric. 25 may be fixed. In this case, for example, the flow openings 251 provided at the four corners around the mounting table 3 correspond to the openings of the conductive member, but the baffle plate 25 itself is provided with openings without providing the flow openings 251. Alternatively, an opening may be provided in the baffle plate 25 itself in addition to the flow opening 251.

  Furthermore, the cathode electrode of the present invention is not limited to the case where the mounting table 3 is provided as in the plasma processing apparatus 2 described above. For example, a high frequency power source for plasma generation is connected to the upper electrode 4 and a position where capacitive coupling can occur with the upper electrode, for example, an upper and lower two frequency type in which an exhaust port 241 is provided on the side wall of the processing vessel, side The present invention can also be applied to an exhaust type plasma processing apparatus.

  And the cathode electrode which can apply this invention is not limited to the mounting base 3 illustrated in embodiment. For example, a sheet-like electrode embedded in a ceramic mounting table may be used as a cathode electrode, a plasma processing apparatus that applies a high frequency only to the upper electrode, or an upper and lower two-frequency type that applies a high frequency to both the upper electrode and the lower electrode. In the plasma processing apparatus, the upper electrode may be a cathode electrode. The material of the conductive member is not limited to metal, and may be, for example, a conductive resin or conductive ceramics.

  The plasma processing apparatus of the present invention is applicable not only to etching an aluminum film, but also to etching a metal film such as an aluminum alloy, titanium, or titanium alloy, an insulating film, a semiconductor film, or a laminated film thereof. Further, the present invention can be applied to plasma processing for processing a target object using other processing gases such as ashing and plasma CVD (Chemical Vapor Deposition) other than etching processing. Furthermore, the object to be processed is not limited to a square substrate, and may be a semiconductor wafer in addition to an FPD substrate.

(Experiment 1)
The model machine of the etching processing apparatus 2 shown in the embodiment is manufactured, and the high frequency power is applied to the mounting table 3 in the case where the dielectric 52 is provided between the processing container 20 and the mesh member. The state between the mounting table 3 and the mesh member when applied was observed. A convex second mesh member 51b (made of aluminum, hereinafter simply referred to as “mesh member 51b”) shown in FIG. 6 is provided at the exhaust port 241 of the exhaust path 24, and oxygen gas is 6000 sccm as a processing gas. Supplied with. The pressure in the processing container 20 was 13 Pa (100 mtorr), and 13.56 MHz and 10 kW were applied from the first high frequency power supply unit 311 and 3.2 MHz and 10 kW were applied from the second high frequency power supply unit 312.
A. Experimental conditions
Example 1
A dielectric 52 made of alumina was provided between the mesh member 51 b and the bottom wall surface of the processing container 20.
(Comparative Example 1)
The mesh member 51b was directly fixed to the bottom wall surface of the processing container 20, and both members were in an electrically conductive state.

B. Experimental result
FIG. 7A shows the result of photographing the state between the mounting table 3 and the mesh member 51b in (Example 1), and FIG. 7B shows the result of (Comparative Example 1). According to the image shown in FIG. 7A, no remarkable light emission is observed in the vicinity of the mesh member 51b, and in the experiment of (Example 1), the discharge between the mounting table 3 and the mesh member 51b is suppressed. I understand that. On the other hand, according to the image shown in FIG. 7B, light emission with high luminance is confirmed on the upper surface of the mesh member 51b, and in the experiment of (Comparative Example 1), the mounting table 3 is relatively strong between the mesh member 51b. It was found that glow discharge occurred. From the above experimental results, when the dielectric 52 is provided between the mesh member 51b and the processing container 20, it is possible to suppress the discharge between the mounting table 3 and the mesh member 51b as compared with the case where this is not provided. It could be confirmed.

(Experiment 2)
Under the same conditions as in (Experiment 1), a small piece of silicon wafer was placed on the mesh member 51b and high frequency power was applied to the mounting table 3 for 7 minutes. The amount of shaving of each small piece was measured.
A. Experimental conditions
(Example 2)
A dielectric 52 is provided between the mesh member 51 b and the processing container 20.
(Comparative Example 2)
The mesh member 51b was directly fixed to the bottom wall surface of the processing container 20, and both members were in an electrically conductive state.

B. Experimental result
According to the results of (Example 2) and (Comparative Example 2), the amount of chipping (741 mm) of the small piece in (Example 2) provided with the dielectric 52 did not provide the dielectric 52 (Comparative Example 2). Was about 40% less than the amount of shaving (1,186 mm). This can be said to be a result of the occurrence of electric discharge between the mounting table 3 and the mesh member 51b is suppressed by providing the dielectric 52, and damage and wear on the surrounding members can be reduced. Here, arcing in the etching processing apparatus 2 was not confirmed within a relatively short time when the experiments of (Example 2) and (Comparative Example 2) were performed. However, as described in the background art, in the actual etching process of the substrate S, the etching apparatus 2 is continuously operated for a long period of time. Therefore, when the dielectric 52 is not provided, the mounting table 3-the upper electrode during this period. The probability that arc coupling will occur due to destabilization of the capacitive coupling between 4 increases. When arcing occurs, the damage and wear of the generated site are expected to be much larger than the amount of wear shown in the above (Comparative Example 2), and even if arcing does not occur, Even in the state where light emission such as the image shown in FIG. 7B occurs, the consumption of the surface of the mesh member is promoted, so that the effect of providing the dielectric 52 is great also in these respects.

It is a longitudinal cross-sectional view which shows the structure of the etching processing apparatus concerning embodiment of this invention. It is a top view which shows the structure inside the processing container of the said etching processing apparatus. It is an enlarged vertical sectional view showing the structure near the exhaust part of the processing container. It is a top view of the mesh member provided in the said processing container, and its support member. It is a top view which shows the modification of a mesh member and its supporting member. It is an expanded longitudinal cross-sectional view which shows the 2nd modification of a mesh member. It is explanatory drawing which shows the experimental result regarding a 1st experiment. It is a longitudinal cross-sectional view which shows the structure of the conventional etching processing apparatus. It is a circuit diagram which shows the equivalent circuit of the said conventional etching processing apparatus.

Explanation of symbols

S FPD substrate (substrate)
DESCRIPTION OF SYMBOLS 2 Etching apparatus 3 Mounting base 4 Upper electrode 7 Control part 20 Processing container 21 Side wall part 22 Carry-in / out port 23 Gate valve 24 Exhaust path 25 Baffle plate 32 Dielectric 34 Lifting pin 35 Lifting mechanism 40 Gas shower head 41 Upper electrode base 42 Gas Diffusion space 43 Process gas supply path 44 Process gas supply parts 51, 51a, 51b
Mesh members 52, 52a
Dielectric 53 Second mesh member 241 Exhaust port 242 Exhaust path connection unit 251 Flow port 311 First high frequency power supply unit 312 Second high frequency power supply unit 511 Bolt 512 Flange

Claims (12)

In a plasma processing apparatus that applies high frequency power between an anode electrode and a cathode electrode that are provided to face each other in a processing container to convert a processing gas into plasma and perform plasma processing on an object to be processed,
An exhaust port disposed around the cathode electrode and exhausting the processing gas;
A conductive member that covers the exhaust port and has an opening through which the processing gas exhausted to the exhaust port flows;
A plasma processing apparatus comprising: a conductive material provided between the conductive member and a conductive wall of the processing container.   The plasma processing apparatus according to claim 1, wherein the conductive member is a metal, and the dielectric is ceramic.   The plasma processing apparatus according to claim 1, wherein the conductive member has a mesh shape.   What is the first conductive member that covers the exhaust port and that is provided in the periphery of the exhaust port, and covers the upper space of the first conductive member, and the first conductive member 2. The plasma processing apparatus according to claim 1, further comprising a second conductive member provided to be spaced apart, wherein the conductive member is a second conductive member.   The plasma processing apparatus according to claim 4, wherein the first conductive member and the second conductive member are metal, and the dielectric is ceramic.   6. The plasma processing apparatus according to claim 4, wherein the first conductive member and the second conductive member have a mesh shape.   The plasma processing apparatus according to claim 4, wherein the first conductive member has a mesh shape, and the second conductive member has a flat plate shape.   The second dielectric material provided between the first conductive member and a conductive wall portion of the processing container. Plasma processing equipment.   The plasma processing apparatus according to claim 1, wherein the cathode electrode and the exhaust port are provided in a lower portion of the processing container. The plasma processing apparatus according to claim 1, wherein the object to be processed is a square substrate having an area of 4.0 m ² or more.   The plasma processing apparatus according to claim 1, wherein the gas is a negative gas.   The plasma processing apparatus according to claim 1, wherein the plasma processing is performed in a pressure atmosphere in a range of 0.67 Pa to 27 Pa.