KR20110040806A - Plasma processing apparatus - Google Patents

Abstract

PURPOSE: A plasma processing apparatus is provided to include a dielectric object between a mesh member covering an exhaust hole and a conductive wall of a processing container, thereby preventing abnormal discharging between a cathode electrode and the mesh member. CONSTITUTION: A baffle plate(25) is arranged around a cathode electrode(3). An exhaust hole(241) is arranged in the lower part of the baffle plate and exhausts a processing gas. A conductive member(51) includes an opening through which the processing gas is exhausted. A dielectric object is located between the conductive member and the lower inner wall of the processing container. The space surrounded by an upper electrode base(41) and an upper electrode(4) configures a gas spreading space(42) for an etching gas.

Description

PLASMA PROCESSING APPARATUS

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma processing apparatus for converting a processing gas into plasma by high frequency electric power, and performing processing such as etching on the target object by the plasma.

In the manufacturing process of flat panels, such as a semiconductor device and a liquid crystal display device, in order to perform process processes, such as an etching process and a film-forming process, to a to-be-processed substrate like a semiconductor wafer or a glass substrate, such as a plasma etching apparatus, a plasma CVD film-forming apparatus, etc. Plasma processing apparatus is used.

The plasma processing apparatus shown in FIG. 8 shows an example of the configuration of a plasma etching apparatus which performs an etching process on a thin film formed on a glass substrate for an FPD (flat panel display), for example. The plasma etching apparatus is provided with an upper electrode 12 serving as a gas shower head which forms a gas supply part in a grounded processing container 10 made of, for example, aluminum and a substrate so as to face the upper electrode 12. It is comprised as the parallel plate type plasma processing apparatus provided with the lower electrode 11 which serves as the mounting table of (S). The upper electrode 12 is connected to the processing container 10 and is configured as an anode electrode, while the lower electrode 11 is in a state that is sufficiently electrically floating with respect to the processing container 10 by the insulating material 14, and is illustrated. It is a cathode electrode connected to the high frequency power supply 15 via a matching circuit (matching circuit) which is not provided. In addition, the peripheral part and side surface of this lower electrode 11 surface are shown by the shield ring 18 which consists of insulators, such as ceramics, for forming a plasma uniformly above the lower electrode 11, as shown in FIG. It may be covered.

The equivalent circuit of the electrically conductive path of the high frequency current in this plasma etching apparatus is shown in FIG. When the processing gas is supplied into the processing container 10 and the high-frequency power is applied between the upper electrode 12 and the lower electrode 11 by the high frequency power supply 15 to convert the processing gas into plasma, the lower electrode 11 and the upper part Since the capacitive coupling C1 is formed between the electrodes 12, the high frequency current from the high frequency power supply 15 is lower than the lower electrode 11 → plasma → upper electrode 12 → wall of the processing vessel 10 → earth. Through the passage, etching is performed on the substrate S mounted on the lower electrode 11 using the plasma-formed processing gas. In detail, the high frequency current returns to the earth of the high frequency power supply 15 through the housing (matching box) of the matching circuit (not shown) at the wall of the processing container 10.

By the way, the board | substrate S for FPDs which are the process targets of the said apparatus tends to become larger, and the processing container 10 is also enlarged by this. When the processing container 10 becomes large, the inductance component of the processing container 10 becomes large, and the impedance of the path of the said high frequency current becomes large. For this reason, the wall part of the processing container 10 which is closer to the cathode electrode than the anode electrode is seen as the anode electrode when viewed from the cathode electrode, so that both members are easily capacitively coupled. Therefore, a method is known in which the impedance is made relatively small by interposing an impedance adjustment mechanism in the current path between the anode electrode and the processing container (Patent Document 1). However, in the case where the lower electrode 11 is a cathode, for example, as in the above-described plasma etching apparatus, the side or bottom surface of the processing container 10 around the lower electrode 11 and the lower electrode 11 It is still in a state where capacitive coupling is easy.

Here, the exhaust path 16 for exhausting the gas after processing the board | substrate S is provided in the bottom surface of the processing container 10, and the foreign material in the exhaust path 16 is provided in the exhaust port of the said exhaust path 16. The mesh member 17 for protection which prevents the fall and invasion of the plasma, and suppresses the invasion and generation | occurrence | production of the plasma in the exhaust path 16 is provided. As this mesh member 17, a metal material is used from a viewpoint of workability and strength. In order to form a uniform plasma, the mesh member 17 is in contact with the processing container 10 based on the so-called stereotyped design idea that the periphery thereof is preferable when viewed from the lower electrode 11. It was on the processing container 10 and a coin.

For this reason, the mesh member 17 provided in the position near the lower electrode 11 of the bottom part of the processing container 10 becomes an anode electrode closer than the upper electrode 12 when seen from the lower electrode 11, and the lower electrode A capacitive coupling (indicated by C2 in FIG. 9) is formed between the 11 and the mesh member 17, for example, to easily generate a glow discharge. The inventors of the present invention have shown that a typical condition under which this phenomenon occurs is in the range of 0.67 Pa to 27 Pa (5 mtorr to 200 mtorr) in the processing vessel 11, and the processing gas is halogen-based gas such as chlorine gas or CF _4. Gas, O ₂ A negative gas such as a gas or the like, that is, a molecule constituting the gas is attached to an electron to generate more negative ions, and this negative ion is a gas that generates more plasma than electrons, and one side of the substrate S It was confirmed that the case was a large one exceeding 1 m and the lower electrode 11 was provided in the mounting table as described above.

In addition, although the vicinity of the exhaust port of the exhaust path 16 into which the gas in the processing container 10 flows becomes various pressure atmospheres according to process conditions such as gas flow rate and pressure, the lowest voltage generally required for generating plasma between electrodes Since silver is a function of the pressure of the space formed between the electrodes, in addition to the above-mentioned factors, glow discharge tends to occur between the lower electrode 11 serving as the cathode and the mesh member 17 in particular.

As such, when unnecessary capacitive coupling is formed between the lower electrode 11 and the mesh member 17 and a locally strong glow discharge is generated, the lower electrode 11 and the upper electrode 12 which are original plasma generating spaces are formed. There is a possibility that the plasma in between may become unstable, for example, causing so-called arcing in which arc-like abnormal discharge is generated on the surface of the member or the substrate S in the processing container 10, and these members or the substrate are caused. In-plane uniformity of substrate S processing may deteriorate due to damage of (S) or wear and tear, and generation of deflected plasma.

Patent Document 1: Japanese Patent Laid-Open No. 2005-340760; Paragraph 0027, FIG. 1

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

In the plasma processing apparatus according to the present invention, a plasma processing apparatus is formed by applying a high frequency power between an anode electrode and a cathode electrode provided to face each other in a processing container to convert a processing gas into plasma, and perform a plasma processing on a target object.

 An exhaust port disposed around the cathode electrode to exhaust the processing gas;

 A conductive member covering the exhaust port and having an opening for flowing a process gas exhausted to the exhaust port;

A dielectric provided between the conductive member and the conductive wall portion of the processing container is provided.

In addition, it is preferable that the said conductive member is a metal, for example, and the said dielectric material is ceramics, and it is preferable that the said conductive member is a mesh shape.

And a second conductive member provided to cover the exhaust port, the first conductive member provided at the periphery of the exhaust port, and a space above the first conductive member, and the second conductive member spaced apart from the first conductive member. The conductive member may be configured as the second conductive member. Also in this case, the first conductive member and the second conductive member are metal, and the dielectric is preferably ceramics. The case where 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 is preferable. The second dielectric may be provided between the first conductive member and the conductive wall portion of the processing container.

Or more for each plasma processing apparatus, the cathode electrode and the air outlet is preferably provided on the lower portion of the processing vessel, the plasma treatment apparatus, the object to be processed is a rectangular substrate area of at least 4.0m ^2, the process gas is negative gas The case where the pressure atmosphere in which the plasma processing is performed is within the range of 0.67 Pa or more and 27 Pa or less is suitable.

According to the present invention, in the parallel plate type plasma processing apparatus, a 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 the so-called abnormal path which reaches the processing container from the cathode electrode provided with the mounting table via the mesh member becomes large, and the cathode electrode and the mesh member are difficult to be capacitively coupled, and abnormal discharge is suppressed. For this reason, generation | occurrence | production of arcing can be suppressed and the damage and the damage of the member, a board | substrate in a process container can be suppressed.

1 is a longitudinal sectional view showing a configuration of an etching processing apparatus according to an embodiment of the present invention;
2 is a plan view showing a structure inside a processing vessel of the etching apparatus;
3 is an enlarged longitudinal sectional view showing a structure near an exhaust part of the processing container;
4 is a plan view of a mesh member and its supporting member provided in the processing container;
5 is a plan view showing a modification of the mesh member and its supporting member;
6 is an enlarged longitudinal sectional view showing a second modification of the mesh member;
7 is an explanatory diagram showing an experimental result according to a first experiment;
8 is a longitudinal sectional view showing a configuration of a conventional etching processing apparatus;
9 is a circuit diagram showing an equivalent circuit of the conventional etching processing apparatus.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment which applied the plasma processing apparatus of this invention to the etching processing apparatus 2 of an FPD board | substrate is demonstrated, referring FIGS. This etching processing apparatus 2 is provided with the processing container 20 which is a vacuum chamber for performing an etching process with respect to the to-be-processed object, for example, the board | substrate S which is an FPD board | substrate in this inside, and this processing container ( 20 is, for example, a planar shape formed in a square shape, and the processing container 20 is grounded via a housing 64 of a matching box described later.

The board | substrate S is a square glass substrate with the length of one side exceeding 1m, and the process container 20 respond | corresponds to the shape of this board | substrate S, for example, about 3.5m one side of a horizontal cross section, and about 3.0m other sides. It is composed of a conductive material having a good thermal conductivity, such as aluminum, for example. One sidewall portion 21 of the processing container 20 is provided with a carrying in and out port 22 for carrying the substrate S into the processing container 20, and the carrying in and out port 22 has a gate valve 23. It is comprised so that opening and closing is possible.

Inside the processing container 20, a mounting table 3 for mounting the substrate S on its upper surface is arranged. The mounting table 3 is electrically connected to the first high frequency power supply section 311 for generating plasma and the second high frequency power supply section 312 for introducing ions into the plasma via matching circuits 62 and 63, respectively. Plasma is generated in the vessel 20 to serve as a cathode electrode for introducing ions in the plasma to the substrate S surface. In addition, the matching circuits 62 and 63 are housed in a conductive housing 64 which is a matching box, and the housing 64 is connected to the bottom wall of the processing container 20 via the conductive pipe member 65. have. The housing 64 is connected to the ground side of the 1st, 2nd high frequency power supply parts 311 and 312, Therefore, the processing container 20 is in the state which is earthed via this housing 64. FIG.

The mounting table 3 is disposed on the bottom surface of the processing container 20 via the dielectric 32, whereby the mounting table 3 serving as the lower electrode is in an electrically floating state in the processing container 20. In addition, the periphery and side surfaces of the surface of the mounting table 3 are covered by a shield ring 33 made of a ceramic material for uniformly forming plasma above the mounting table 3.

Moreover, the mounting apparatus 3 is provided with the conveying apparatus which is not shown outside of the etching processing apparatus 2, and the lifting pin 34 for carrying out the board | substrate S between the said mounting apparatus 3. . The lifting pin 34 is configured to be driven from the surface of the mounting table 3 by the elevating mechanism 35 so as to allow the substrate S to be passed between the external transport means and the mounting table ( It is provided in the surface of 3), and the board | substrate S can be raised and lowered between the positions where the board | substrate S is mounted.

On the other hand, above the mounting table 3 inside the processing container 20, a flat upper electrode 4, which is an anode electrode, is provided to face the surface of the mounting table 3, and the upper electrode 4 is provided. It is supported by the upper electrode base 41 of the square plate shape. These upper electrodes 4 and the upper electrode base 41 are made of aluminum, for example. In addition, the upper surface of the upper electrode base 41 is fixed to the ceiling of the processing vessel 20 via the dielectric 45, and the upper electrode 4 and its space 41 are formed of the impedance adjusting mechanism 6 and the conductive portion. It is electrically connected to the processing container 20 via the cover body 61.

The impedance adjusting mechanism 6 serves to adjust the impedance from the upper electrode 4 to the processing vessel 20, and a circuit including a capacitor, for example, a variable capacitor, is used, and the capacitance of the plasma is used. The inductance L of the path from (C1) and the upper electrode 4 to the lower part of the processing container 20 is canceled by the capacitance component C of the impedance adjusting mechanism 6. As a result, the impedance adjusting mechanism 6 adjusts the impedance of the path of the mounting table 3 (lower electrode) → plasma → upper electrode 4 → impedance adjustment mechanism 6 → processing vessel 20 → ground. 1 / ωC1 + ωL-1 / ωC), and serves to make it smaller than the impedance of the abnormal path described later.

The space surrounded by the upper electrode base 41 and the upper electrode 4 constitutes the gas diffusion space 42 of the etching gas. Hereinafter, these upper electrodes 4, the upper electrode base 41, and the like are collectively referred to as a gas shower head 40. In addition, a processing gas supply path 43 is provided at the ceiling of the processing container 20 so as to be connected to the gas diffusion space 42, and the other end of the processing gas supply path 43 is processed via the gas diffusion space 42. It is connected with the process gas supply part 44 for supplying etching gas in the container 20.

Here, as shown in FIG. 1 and FIG. 2, in the space between the side surface of the mounting table 3 and the side wall portion 21, a flat baffle plate made of, for example, an aluminum member whose surface is anodized. 25 is arrange | positioned. The baffle plate 25 is arrange | positioned in the outer side area | region of the four sides of the mounting table 3, The exhaust port 241 mentioned later from the space in which the plasma is formed between the mounting table 3 and the gas shower head 40 is formed. It is located at the position blocking the front of the). The baffle plate 25 restricts the flow of the etching gas supplied to the surface of the substrate S on the mounting table 3 directly into the exhaust port 241 to suppress the inclination of the flow of gas, and thus the entire surface of the substrate S. Serves to allow the etching gas to flow uniformly. As shown in FIG. 2, the four holes on the outer side of the baffle plate 25 are provided with a through hole 251 in which the baffle plate 25 is not provided, and the etching gas supplied into the processing container 20 is It flows to the downstream side through this baffle plate 25.

As shown in FIGS. 1-3, the opening part which comprises the horizontally long exhaust port 241 is formed in the bottom wall of the processing container 20. As shown in FIG. The exhaust pipe which forms the exhaust path 24 is connected below this exhaust port, and the upstream end of the said exhaust pipe is extended by the expansion opening 242 in the shape corresponding to the shape of the horizontally long exhaust port 241, and The flange part formed in the opening edge of the expansion opening part 242 is hermetically joined to the lower surface side of the bottom wall of the processing container 20. This exhaust port 241 is provided in eight places, for example, in two places along each side wall part 21 in the bottom wall of the processing container 20 between the mounting table 3 and the side wall part 21, In the exhaust pipe downstream of each of these exhaust ports 241, a pressure regulating mechanism 26 constituted by, for example, a butterfly valve is provided. The exhaust pipe is joined to the downstream side of the pressure regulating mechanism 26 and is connected to the vacuum pump 27 at the downstream end.

Each exhaust port 241 is covered by a mesh member 51 made of metal such as aluminum, which is a conductive member, as shown in Figs. 3 and 4 (a), and the mesh member 51 as described in the background art. Plays a role of suppressing the falling and invasion of foreign matter into the exhaust passage 24 and 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 Figs. 3 and 4 (b), the mesh member 51 is a bolt 511 made of a dielectric made of ceramic, for example, through a small-piece dielectric 52 made of ceramic, for example, alumina or the like. It is fastened to the bottom wall surface of the processing container 20, etc., and is fixed to the bottom wall surface through the clearance gap of 5 mm-20 mm, for example. The dielectric material 52 locally supports the mesh member 51 at eight locations around the exhaust port 241, and the dielectric material 52 is disposed between the metal processing container 20 and the mesh member 51. For example, as shown in FIG. ) Is intervened.

As shown in FIG. 1, the etching apparatus 2 is connected to the control unit 7. The control part 7 consists of a computer which is equipped with the CPU which is not shown in figure, and a memory | storage part, for example, the operation | movement of the said etching processing apparatus 2, ie, the board | substrate S is carried in the process container 20, A program is recorded in which a group of steps (commands) related to control and the like related to the operation from the etching process to the carrying out of the substrate S mounted on the mounting table 3 is combined. This program is stored in a storage medium such as a hard disk, a compact disk, a magnet optical disk, a memory card, for example, and is installed in a computer there.

Hereinafter, the operation of the etching processing apparatus 2 according to the present embodiment will be described. When the user selects the process recipe of the desired etching process with respect to the control part 7 via the operation part which is not shown initially, the control part 7 outputs a control signal to each part of the etching process apparatus 2 based on this process recipe. Thus, a predetermined etching process is performed on the substrate S in this way.

Specifically, first, the gate valve 23 is opened, and the substrate S having an Al film formed thereon is brought into the processing container 20 by an external conveying means (not shown) to mount the mounting area of the mounting table 3. It is conveyed to the picking position on the upper side of. Then, the lifting pin 34 is raised, the substrate S is received from the conveying means from the conveying means at the lifting pin 34, and the lifting pin 34 is lowered to mount the substrate S on the mounting table 3. Mount on the mounting area of the top. In the meantime, the conveying means which received the board | substrate S exits the process container 20, and closes the loading-in / out port 22 by the gate valve 23. As shown in FIG.

Next, the process gas supply part 44 discharges the etching gas for etching process, for example, halogen-type negative gas, such as chlorine gas, toward the board | substrate S, and simultaneously makes the internal space of the process container 20 predetermined pressure. Adjust with The high frequency power of 13.56 MHz, for example, is 5.5 kW from the first high frequency power supply section 311 for plasma generation, and the high frequency power of 3.2 MHz, for example, is received from the second high frequency power supply 312 for ion implantation in the plasma. 1.0 kW is applied to the mounting table 3, respectively, and the etching process is performed on the substrate S based on the main reaction shown in the following formula (1) using a plasma formed in the space above the substrate S. .

3Cl ^* + Al → AlCl ₃ ‥ (1)

Referring to the flow of the etching gas in the processing vessel 20 at this time, the etching gas supplied from the gas shower head 40 is converted into plasma while falling between the upper and lower electrodes 4 and 3 and the substrate S ), Flows through the surface of the board | substrate S and on the baffle plate 25, and flows into the flow-through port 251. FIG. And it exhausts to the exhaust path 24 through each exhaust port 241 in the space below the baffle board 25. As shown in FIG.

On the other hand, by turning the etching gas into plasma, the high frequency electric power is mounted on the mounting table (lower electrode) 3 → plasma → upper electrode 4 (gas shower head 40) → impedance adjustment mechanism 6 → processing vessel 20 →. The so-called normal path | route of the ground of the housing 64 which is a matching box → the 1st, 2nd high frequency power supply 311, 312 side flows. At this time, the mesh member 51 which covers the exhaust port 241 of the exhaust path 24 is provided in the vicinity of the mounting table 3 which is a lower electrode, and the atmosphere around this mesh member 51 is the same as the background art demonstrated. As the gas discharged in the same flows toward the exhaust port 241, various pressure atmospheres are formed according to the process recipe. For this reason, although the mesh member 51 may become the pressure atmosphere which is easy to generate | occur | produce glow discharge between the mounting tables 3, the mesh member 51 which is a conductor seen from the mounting board 3 is the dielectric material 52. By being supported by the structure, the dielectric material 3 is placed through the so-called abnormal path of the mounting table 3, the plasma mesh member 51, the processing container 20, and the ground, including the shield ring 33. The capacitance formed between the mesh member 51 and the processing container 20 is applied, and the impedance of the abnormal path increases. As a result, the mesh member 51 becomes invisible to the immediately adjacent anode electrode when viewed from the mounting table 3 which is the cathode electrode, thereby suppressing the occurrence of glow discharge between the mounting table 3 and the mesh member 51, Moreover, even if discharge generate | occur | produces, the extent can be suppressed small.

According to the etching apparatus 2 which concerns on this embodiment, there exist the following effects. In the etching processing apparatus 2 which is a parallel plate type plasma processing apparatus, the dielectric material 52 is provided between the mesh member 51 which covers the exhaust port 241 provided in the processing container 20, and the conductive processing container 20. It is in a state prepared. As a result, the impedance of the so-called abnormal path from the cathode electrode provided with the mounting table 3 to the processing vessel 20 through the mesh member 51 becomes large, and the cathode electrode and the mesh member 51 become difficult to be capacitively coupled. Abnormal discharge can be suppressed. For this reason, generation | occurrence | production of arcing can be suppressed and the damage and the loss of the member, the board | substrate S in the processing container 20 can be suppressed. In addition, it is possible to suppress the inclination of the plasma due to destabilization of the capacitive coupling between the mounting table 3 and the upper electrode 4, and to perform the substrate S processing with high in-plane uniformity.

Furthermore, when detailed information with respect to this effect, in the case of a large-sized substrate (S) of the substrate area to or more than 1m ^2, particularly at least 4m ^2, the capacitive coupling between the cathode and the process container 20 or the surrounding member Since it is easy to carry out, interposing the impedance adjustment mechanism 6 between the anode electrode and the processing container 20 is performed. However, the vicinity of the exhaust port 241 of this processing container 20 becomes various pressure atmospheres by a process recipe, and it is easy to produce a glow discharge especially in the pressure range of 0.67 Pa-27 Pa (5 mtorr-200 mtorr). When a negative gas is used as the processing gas, such as halogen-based gas such as chlorine gas, the dissociation degree of the gas is large, so that the glow discharge is more likely to occur, and the mesh member 51 is provided in the etching processing apparatus 2 having such conditions. The structure which electrically floated with respect to the processing container 20 performs extremely high in-plane uniformity process with respect to the large sized substrate S, and is extremely effective.

In addition, in the above-mentioned embodiment, although the plasma processing apparatus 2 of the type provided with the impedance adjustment mechanism 6 was illustrated, the present invention also applies to the plasma processing apparatus of the type which is not equipped with such an impedance adjustment mechanism 6. By applying this, the impedance of the abnormal path mentioned above can be enlarged and generation | occurrence | production of abnormal discharge can be suppressed. However, the provision of the impedance adjusting mechanism 6 facilitates the adjustment of reducing the impedance of the path normal to the impedance of the abnormal path, and the dielectric material 52 between the mesh member 51 and the processing container 20. The effect of increasing the effectiveness of the present invention by disposing) is obtained.

The structure of the mesh member or the dielectric is not limited to those illustrated in Figs. 4A and 4B. For example, as shown in FIG. 5 (a) and FIG. 5 (b), the dielectric 52a which surrounds the whole periphery of the exhaust port 241 of the exhaust path 24 is provided, for example, the said dielectric 52a The mesh member 51a which has the flange part 512 suitable for the shape of () 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, foreign matters can fall and enter the exhaust path 24 through this gap.

In addition, as shown in FIG. 6, in the state which made the metal mesh member 53 contact the peripheral part of the exhaust port 241, it fixed with the metal bolt, for example, and the space above the said mesh member 53 is shown. The second mesh member 51b is formed in a convex shape covering the gap and spaced apart from the mesh member 53, 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 of the claims, and the mesh member 53 corresponds to the first conductive member of the claims. In this case, it is possible to cope by adding the second mesh member 51b into the processing container 20 provided with the existing mesh member 53 provided in contact with the periphery of the exhaust port 241, thereby remodeling the apparatus. There is an advantage that it is easy. It goes without saying that the second dielectric may be interposed between the mesh member 53 and the processing container 20 in this example.

In addition, as another example of providing the first conductive member and the second conductive member, for example, the baffle plate 25 is used as the second conductive member, and the baffle plate is formed on the sidewall surface of the processing container 20 via a dielectric material. It is good also as a structure which fixes (25). In this case, although the through holes 251 provided at four corners around the mounting table 3 correspond to the openings of the conductive member, the openings are provided in the baffle plate 25 itself without providing the through holes 251. In addition to the flow passage 251, the opening may be provided in the baffle plate 25 itself.

In addition, the cathode of this invention is not limited to the case where it is equipped in the mounting table 3 like the plasma processing apparatus 2 mentioned above. For example, the high frequency power supply for plasma generation is connected to the upper electrode 4, and the exhaust port 241 is provided at a position where capacitive coupling can be generated between the upper electrodes, for example, in the side wall of the processing container. The present invention can also be applied to the plasma processing apparatus of the upper and lower two-frequency type and the side exhaust type.

The cathode electrode to which the present invention can be applied is not limited to the mounting table 3 exemplified in the embodiments. For example, a sheet-shaped electrode embedded in a ceramic mounting table may be used as a cathode electrode, and a plasma processing apparatus for applying a high frequency only to an upper electrode, or an upper and lower two-frequency type for applying 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. In addition, the material of the conductive member is not limited to metal, for example, conductive resin, conductive ceramics, or the like may be used.

In addition, the plasma processing apparatus of the present invention is applied not only to etching processing of an aluminum film but also to etching of metal films, insulating films, semiconductor films, and laminated films thereof, such as aluminum alloys, titanium and titanium alloys. Moreover, it can apply to the plasma process which performs a process with respect to a to-be-processed object using other process gas, such as ashing and plasma CVD (Chemical Vapor Deposition) other than an etching process. The object to be processed is not limited to the rectangular substrate, but may be a semiconductor wafer or the like in addition to the FPD substrate.

Example

(Experiment 1)

In the case where the model machine of the etching processing apparatus 2 shown in embodiment is produced, and when the dielectric body 52 is provided between the processing container 20 and the mesh member, and not provided, the mounting table 3 has a high frequency. The state between the mounting table 3 and the mesh member when electric power was applied was observed. A convex second mesh member 51b (made of aluminum, hereinafter simply referred to as "mesh member 51b") provided in the exhaust port 241 of the exhaust path 24 is provided with a processing gas. As an oxygen gas, 6000 sccm was supplied. The pressure in the processing vessel 20 was set to 13 Pa (100 mtorr), and high frequency powers of 13.56 MHz and 10 kW were applied from the first high frequency power supply section 311 and 3.2 MHz and 10 kW from the second high frequency power supply section 312.

A. Experimental Conditions

(Example 1)

An alumina dielectric 52 was provided between the mesh member 51b 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 made electrically connected.

B. Experimental Results

The state between the mounting table 3 and the mesh member 51b in (Example 1) is shown in FIG. 7 (a), and the result of (comparative example 1) is shown in FIG. 7 (b). According to Fig. 7A, no significant 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. Can be. On the other hand, according to FIG. 7 (b), light emission with high luminance is confirmed on the upper surface of the mesh member 51b, and in the experiment of (Comparative Example 1), relatively strong between the mounting table 3 and the mesh member 51b. It was found that glow discharge was occurring. From the above experimental results, when the dielectric 52 is provided between the mesh member 51b and the processing container 20, the discharge between the mounting table 3 and the mesh member 51b is compared with the case where the dielectric member 52 is not provided. It was confirmed that it can suppress.

(Experiment 2)

Under the same conditions as in (Experiment 1), when a small piece of silicon wafer was placed on the mesh member 51b, high frequency power was applied to the mounting table 3 for 7 minutes, and when the dielectric 52 was not provided. The amount of wear of the piece during the corresponding period was measured.

A. Experimental Conditions

(Example 2)

The dielectric 52 was provided between the mesh member 51b 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 made electrically connected.

B. Experimental Results

According to the results of (Example 2) and (Comparative Example 2), the wear amount 741A of the small piece in (Example 2) in which the dielectric 52 was provided (Comparative Example 2) It was about 40% less than the wear rate of 1,186 Å. This can be said to be the result of the occurrence of the discharge between the mounting table 3 and the mesh member 51b being suppressed by providing the dielectric 52 to reduce damage and wear and tear on the surrounding members. Here, arcing in the etching processing apparatus 2 was not confirmed within a relatively short time which the experiment of (Example 2) and (Comparative Example 2) was performed. However, as described in the background art, in the etching process of the actual substrate S, since the etching processing apparatus 2 is continuously operated for a long time, when the dielectric 52 is not provided, the mounting table 3 is used during this period. Capacitive coupling between the upper electrodes 4 becomes unstable, and the probability of arcing increases. When arcing has occurred, the damage and loss of the generated site are expected to be particularly large compared to the amount of wear shown in (Comparative Example 2) described above, and even if arcing does not occur, light emission as shown in FIG. Even in this state, since the consumption of the surface of the mesh member is promoted, the effect of providing the dielectric 52 is also great in this respect.

S: FPD substrate (substrate) 2: etching processing apparatus
3: mounting table 4: upper electrode
7: control unit 20: processing container
21: side wall portion 22: carrying in and out
23: gate valve 24: exhaust passage
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 passage
44: process gas supply part 51, 51a, 51b: mesh member
52, 52a: dielectric 53: second mesh member
241: exhaust port 242: exhaust path connecting portion
251: through hole 311: first high frequency power supply
312: second high frequency power supply unit 511: volt
512: flange

Claims (6)

In the plasma processing apparatus which applies a high frequency electric power between the anode electrode and the cathode electrode which oppose each other in the processing container, plasmaizes a process gas, and performs a plasma process with respect to a to-be-processed object,
A baffle plate disposed around the cathode electrode;
An exhaust port disposed below the baffle plate around the cathode electrode to exhaust the processing gas;
A conductive member covering the exhaust port and having an opening for flowing a process gas exhausted to the exhaust port;
And a dielectric provided interposed between the conductive member and the bottom inner wall of the processing container.
Plasma processing apparatus. The method of claim 1,
The conductive member is a metal, and the dielectric is ceramics.
Plasma processing apparatus. The method according to claim 1 or 2,
The conductive member has a mesh shape
Plasma processing apparatus. The method of claim 1,
A second conductive member provided to cover the exhaust port, a first conductive member provided at a periphery of the exhaust port, and an upper space of the first conductive member and spaced apart from the first conductive member; The conductive member is a second conductive member
Plasma processing apparatus. The method of claim 4, wherein
The first conductive member and the second conductive member are metal, and the dielectric is ceramics.
Plasma processing apparatus. The method according to claim 4 or 5,
The first conductive member and the second conductive member is characterized in that the mesh shape
Plasma processing apparatus.

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