JP2006253733A - Plasma processing apparatus and method of cleaning the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus in which efficient cleaning is possible, and a method of cleaning the same. <P>SOLUTION: An exhaust pipe 37 is directly connected to a diffusion section 29a for diffusing process gas, formed inside an upper electrode 26, wherein the upper electrode 26 functions as a shower head. An exhaust line L4 for cleaning, with the exhaust pipe 37 at one end thereof, is connected to an exhaust outlet 36, and is resultantly connected to an exhaust line L3 for exhausting gases inside a chamber 11. Cleaning gas supplied from a cleaning gas line L2 passes through the inside of the chamber 11 and is exhausted through the inside of the upper electrode 26. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a plasma processing apparatus that performs predetermined processing on an object to be processed using plasma, and a cleaning method thereof.

  Various CVD (Chemical Vapor Deposition) apparatuses are used for manufacturing electronic devices such as semiconductor devices and liquid crystal display devices. Among these, a plasma CVD apparatus can form a high-quality film and is widely used.

  A plasma CVD apparatus forms a film on a target object such as a semiconductor wafer by a plasma CVD method in a decompressed chamber. In this film forming process, a film is formed not only on the surface of the object to be processed but also on the surface of the chamber member (such as the inner wall). The film formed in the chamber reduces the yield, for example, causes particles. Therefore, it is necessary to periodically clean the inside of the chamber to remove the deposited film.

  As a method for cleaning the inside of the chamber, so-called remote plasma cleaning is known in which cleaning gas plasma is generated outside the chamber, and the generated plasma is introduced into the chamber for cleaning.

  The remote plasma cleaning will be described below with reference to the drawings. FIG. 12 is a schematic view of a parallel plate type plasma CVD apparatus 101 that can be cleaned using remote plasma cleaning.

  As shown in FIG. 12, a plasma CVD apparatus 101 includes a chamber 102, a workpiece W, a susceptor 103 that functions as a lower electrode, a pump 104 that can evacuate the chamber 102, and many And a shower head 106 that supplies a film forming gas from the gas hole 105 to the entire surface of the workpiece W and functions as an upper electrode. In the shower head 106, fine diffusion paths 107 for diffusing the process gas into the numerous gas holes 105 are formed. In the film formation process, plasma is generated by applying high-frequency power to the upper and lower electrodes while a film formation gas is supplied between the susceptor 103 and the shower head 106. A predetermined film is formed on the surface of the workpiece W by the generated film forming gas plasma.

  A cleaning gas line 108 is connected to the plasma CVD apparatus 101. The cleaning gas line 108 includes a cleaning gas source 109 and a plasma generator 110. The fluorine-based gas supplied from the cleaning gas source 109 is converted into plasma in the plasma generator 110. In the cleaning step, cleaning gas plasma or fluorine radicals in the plasma are selectively introduced into the chamber 102 from the cleaning gas line 108. The film deposited in the chamber 102 is etched and removed by fluorine radicals in the introduced plasma, in particular.

The plasma CVD apparatus 101 as described above has the following problems (1) to (3).
(1) In the cleaning step, cleaning gas plasma (remote plasma) is introduced into the chamber 102 from a dedicated gas inlet 111 provided on the side wall of the chamber 102 or the like. The film deposited on the wall surface of the chamber 102, the surface of the susceptor 103, etc. by the cleaning gas easily comes into contact with the cleaning gas and is removed relatively easily.

  On the other hand, the gas hole 105 and the diffusion path 107 of the shower head 106 function as a process gas path and have a fine structure, so that a film is easily deposited. However, it is difficult for the cleaning gas to enter the fine gas holes 105 and the diffusion path 107, and it takes a long time to perform sufficient cleaning. For this reason, the cleaning of the shower head 106 controls the cleaning process.

  When the cleaning time is long, that is, it takes a long time to clean the shower head 106, not only the throughput is lowered, but other chamber members are deteriorated due to excessive cleaning. However, if the cleaning time is short, the shower head 106 is not sufficiently cleaned, particles increase, and the yield decreases. As described above, the conventional plasma CVD apparatus capable of remote plasma cleaning has a problem that it takes time to clean the shower head and it is difficult to perform efficient cleaning.

  (2) The gas inlet 111 for the cleaning gas is provided with a lid 112 having a slit 112a, and the cleaning gas is introduced into the chamber 102 through the lid 112. The lid 112 covers the gas inlet 111 and is provided to make the wall surface of the chamber 102 as flat as possible. When the lid 112 is not used, plasma formation at the gas inlet 111 becomes unstable and abnormal discharge is likely to occur. Thus, by providing the lid member 112, abnormal discharge can be reduced.

  However, when the cleaning gas is introduced through the lid material 112, radicals that are cleaning active species are lost. As a result, the activity of the cleaning gas decreases, and the cleaning speed decreases. As described above, in the conventional plasma CVD apparatus capable of remote plasma cleaning, the activity of the cleaning gas plasma is lost by providing the lid material, and the cleaning gas activity is not fully utilized, so that efficient cleaning is performed. There was a problem that it was difficult to break.

(3) Further, the cleaning gas inlet 111 is formed with a relatively large diameter in order to increase the supply amount of the cleaning gas. The lid member 112 is provided so as to cover the entire opening.

  However, since the opening is large, even if the cleaning gas is supplied at a large flow rate, the supply pressure (supply speed) from the cleaning gas inlet 111 cannot be increased so much. Moreover, since it supplies through the slit of the cover material 112, when the gas flow which passed the adjacent slit interferes, the flow velocity falls further. For this reason, since the supply rate of the cleaning gas to the center of the chamber 102, that is, the shower head 106 is low, the cleaning gas hardly enters the shower head 106, and a sufficiently high cleaning speed of the shower head 106 cannot be obtained.

  Thus, in the conventional plasma CVD apparatus capable of remote plasma cleaning, it is difficult to supply the cleaning gas into the chamber at a high supply pressure (speed), and high-speed and efficient cleaning is difficult to be performed. There was a problem.

  In view of the above circumstances, the present invention relates to a plasma processing apparatus capable of efficient cleaning and a cleaning method thereof.

In order to achieve the above object, a plasma processing apparatus according to the first aspect of the present invention provides:
A chamber;
A cleaning gas line for supplying a cleaning gas for cleaning the inside of the chamber into the chamber;
A gas activation means disposed in the cleaning gas line and activating the cleaning gas;
The cleaning gas that is provided on the wall of the chamber and is activated by the gas activating means passes through a plurality of slits that are densely formed so that interference of gas passing through adjacent slits is suppressed, A gas inlet supplied into the chamber;
It is characterized by comprising.

  In the above-described configuration, the plasma processing apparatus further diffuses the process gas line that supplies a predetermined process gas into the chamber and the process gas that is connected to the process gas line and introduced from the process gas line. A diffusion path, a diffusion electrode connected to the diffusion path, and having a plurality of gas holes for supplying the process gas diffused by the diffusion path into the chamber, to which a high frequency power can be applied, and one end of the process electrode A cleaning gas exhaust line connected to at least one of the gas line and the diffusion path, the other end connected to an exhaust means, and exhausting the cleaning gas from the chamber may be provided.

  The plasma processing apparatus may further include a process gas exhaust line for exhausting the process gas introduced into the chamber from the process gas line, and the process gas exhaust line may be exhausted by an exhaust unit.

  In the plasma processing apparatus, the chamber includes an exhaust port, the process gas exhaust line includes a valve provided between the exhaust unit and the exhaust port, and the other end of the cleaning gas exhaust line is connected to the process. The exhaust unit may be connected between the valve of the gas exhaust line and the exhaust unit, and the exhaust unit may exhaust the interior of the chamber through the cleaning gas exhaust line with the valve closed.

  In the above configuration, the gas activation means may generate plasma of the cleaning gas.

In order to achieve the above object, a plasma processing apparatus cleaning method according to a second aspect of the present invention comprises:
A chamber, a cleaning gas line for supplying a cleaning gas for cleaning the inside of the chamber into the chamber, and a gas activation means disposed in the cleaning gas line and activating the cleaning gas. A plasma processing apparatus cleaning method comprising:
Introducing the cleaning gas activated by the gas activating means into the chamber through a plurality of slits formed densely so as to suppress interference of gas passing through adjacent slits; ,
And an exhaust step of exhausting the cleaning gas introduced into the chamber from the chamber.

  In the above configuration, the plasma processing apparatus includes a process gas exhaust unit for exhausting the process gas introduced into the chamber. In the exhaust process, the process gas exhaust unit may exhaust the process gas. Good.

  In the above configuration, the plasma processing apparatus includes a valve provided between the process gas exhaust unit and an exhaust port of the chamber. In the exhaust process, the valve is closed, The inside of the chamber may be evacuated.

  According to the present invention, a plasma processing apparatus capable of efficient cleaning and a cleaning method thereof are provided.

A plasma processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. Hereinafter, as a plasma processing apparatus, a so-called parallel plate type plasma CVD (Chemical Vapor Deposition) apparatus will be described as an example. This plasma processing apparatus uses a nitrogen trifluoride (NF ₃ ) plasma between a film forming process for forming a silicon fluoride oxide (SiOF) film on a semiconductor wafer (hereinafter referred to as wafer W) and the film forming process. And a cleaning process for performing cleaning.

FIG. 1 shows a configuration of a plasma processing apparatus 10 according to the present embodiment.
As shown in FIG. 1, the plasma processing apparatus 10 includes a chamber 11, a process gas line L1, a cleaning gas line L2, an exhaust line L3, and a system controller 100.

  The chamber 11 is a reaction vessel that can be depressurized to a vacuum. As will be described later, plasma CVD is performed inside the chamber 11 and the wafer W is subjected to surface treatment.

The process gas line L1 supplies process gas to the chamber 11. The process gas is composed of tetrafluorosilane (SiF ₄ ), silane (SiH ₄ ), oxygen (O ₂ ), and argon (Ar) as a carrier gas. The process gas line L 1 connects the SiF ₄ source SA, the SiH ₄ source SB, the O ₂ source SC, and the Ar source SD to the chamber 11. Each of the SiF ₄ source SA, the SiH ₄ source SB, the O ₂ source SC, and the Ar source SD is connected to the chamber 11 via a mass flow controller or the like (not shown). The lines connecting the SiF ₄ source SA, the SiH ₄ source SB, the O ₂ source SC and the Ar source SD and the chamber 11 are converged to one line. Thereby, SiF ₄ , SiH ₄ , O ₂ and Ar are mixed at a predetermined ratio and supplied to the chamber 11. The process gas is turned into plasma inside the chamber 11, whereby a SiOF film is formed on the surface of the wafer W.

The cleaning gas line L2 supplies a cleaning gas to the chamber 11. The cleaning gas is composed of NF ₃ and Ar as a carrier gas. The cleaning gas line L2 connects the NF ₃ source SE and the Ar source SF to the chamber 11. Each of the NF ₃ source SE and the Ar source SF is connected to the chamber 11 via a mass flow controller or the like (not shown). The lines connecting the NF ₃ source SE and the Ar source SF and the chamber 11 are once converged to one line, and then branched into two lines and connected to the chamber 11 again. Accordingly, NF ₃ and Ar are mixed at a predetermined ratio and supplied to the chamber 11 from two lines.

A plasma generator 12 is provided in the cleaning gas line L2. The plasma generator 12 is disposed at a once converged portion of the cleaning gas line L2. The plasma generator 12 includes a plasma generation mechanism therein, and generates plasma of gases (NF ₃ and Ar) supplied to the plasma generator 12. The plasma generator 12 selectively exhausts mainly fluorine radicals in the generated plasma. As a result, the cleaning gas mainly containing fluorine radicals is supplied to the chamber 11 connected to the exhaust side of the plasma generator 12.

  A turbo molecular pump (TMP) 13 is connected to the exhaust line L3. A dry pump (not shown) is provided downstream of the turbo molecular pump 13 so that the inside of the chamber 11 can be decompressed to a vacuum level. An automatic pressure controller (APC) 14 is provided between the turbo molecular pump 13 and the chamber 11. The interior of the chamber 11 is set to a predetermined pressure by the automatic pressure control device 14.

  The system controller 100 controls the entire plasma processing apparatus 10 including a film forming operation and a cleaning operation. The system controller 100 includes a timer, for example, a software timer.

  FIG. 2 is a cross-sectional view of the chamber 11 of the plasma processing apparatus 10 shown in FIG. For easy understanding, various gas sources and the like connected to the process gas line L1 are not shown in FIG.

  The chamber 11 has a substantially cylindrical shape. The chamber 11 is made of, for example, aluminum whose surface is anodized. The chamber 11 is grounded. A gate valve (not shown) is provided on the side wall of the chamber 11. The wafer W is carried into and out of the chamber 11 via the gate valve.

  A substantially cylindrical susceptor support 15 is provided at the center of the bottom of the chamber 11. A susceptor 17 is provided on the susceptor support 15 via an insulator 16 such as ceramic. The susceptor support 15 is connected to an elevating mechanism (not shown) provided below the chamber 11 via a shaft 18 and is configured to be able to elevate together with the susceptor 17.

  A refrigerant chamber 19 is provided inside the susceptor support 15. A refrigerant pipe 20 is connected to the refrigerant chamber 19, and the refrigerant is introduced into the refrigerant chamber 19 through the refrigerant pipe 20. The coolant is controlled to a predetermined temperature, and the coolant circulates in the coolant chamber 19, and the cold heat is transferred to the wafer W through the susceptor 17, whereby the wafer W is controlled to a desired temperature.

  The lower part of the susceptor support 15 is covered with a bellows 21 made of stainless steel or the like. The bellows 21 has an upper end fastened to the lower surface of the susceptor support 15 and a lower end fastened to the bottom surface of the chamber 11 with screws or the like. The bellows 21 separates the normal pressure part below the susceptor support 15 and the vacuum part in the chamber 11. The bellows 21 expands and contracts according to the lifting / lowering operation of the susceptor support 15 and always maintains airtightness.

  The upper center of the susceptor 17 is formed in a convex disk shape, and an electrostatic chuck (not shown) having substantially the same shape as the wafer W is provided thereon. The susceptor 17 is a mounting table for the wafer W, and the wafer W placed on the susceptor 17 is electrostatically attracted by Coulomb force.

  The susceptor 17 also functions as a lower electrode. A first high frequency power supply 22 is connected to the susceptor 17, and a first matching unit 23 is interposed in the power supply line. The first high-frequency power source 22 has a frequency in the range of 0.1 to 13 MHz, and applying a frequency in such a range does not damage the wafer W that is the object to be processed. Appropriate ion action can be provided. The susceptor 17 is grounded via a high pass filter (HPF) 24.

  An annular focus ring 25 is arranged at the upper peripheral edge of the susceptor 17 so as to surround the wafer W placed on the electrostatic chuck. The focus ring 25 is made of silicon or the like. The focus ring 25 effectively collects plasma on the wafer W disposed on the inner side of the focus ring 25 to enable efficient and highly uniform plasma processing.

  The susceptor support 15 and the susceptor 17 are formed such that lift pins (not shown) for transferring the wafer W can pass therethrough. The lift pin can be moved up and down by a cylinder or the like. The lift pins can be lifted through the susceptor 17, and the wafer W is placed on the susceptor 17 by the lifting pins.

  An upper electrode 26 is provided above the susceptor 17 so as to face the susceptor 17 in parallel. The upper electrode 26 is supported on the upper portion of the chamber 11 via an insulating material 27. The upper electrode 26 includes an electrode plate 28 and an electrode support 29.

  The electrode plate 28 forms a surface facing the susceptor 17 or the wafer W. The electrode plate 28 includes a large number of fine gas holes 28a on almost the entire surface thereof. The electrode plate 28 is made of, for example, aluminum, silicon, SiC or amorphous carbon whose surface is anodized. The susceptor 17 and the electrode plate 28 are separated from each other by about 10 to 60 mm, for example.

  An electrode plate 28 is screwed to the electrode support 29. The electrode support 29 is made of a conductive material, for example, aluminum whose surface is anodized. The electrode support 29 has a refrigerant structure (not shown) therein. The cooling structure prevents the upper electrode 26 from being overheated.

  The electrode support 29 includes a gas introduction pipe 30. The gas introduction pipe 30 constitutes one end of the process gas line L <b> 1, and the process gas is supplied into the chamber 11 through the gas introduction pipe 30. The gas introduction pipe 30 is connected to the process gas line L1 via the valve V1.

  The electrode support 29 includes a hollow diffusion portion 29a connected to the plurality of gas holes 28a of the electrode plate 28 therein. The diffusion portion 29a is patterned into a predetermined shape to constitute a fine diffusion path. The gas supplied from the gas introduction pipe 30 is planarly diffused by the diffusion part 29a and supplied to the gas hole 28a. Thereby, the process gas is evenly supplied to the entire surface of the wafer W from the plurality of gas holes 28a. Thus, the upper electrode 26 has a so-called shower head structure.

  The upper electrode 26 is connected to the second high frequency power supply 32 via the second matching unit 31. The second high frequency power supply 32 applies a frequency in the range of 13 to 150 MHz, for example. By applying high-frequency power (RF power), high-density plasma is generated between the lower electrode and the susceptor 17. The upper electrode 26 is grounded via a low-pass filter (LPF) 33.

  A cleaning gas inlet 34 is provided on the side wall of the chamber 11. As shown in FIG. 3, for example, two cleaning gas inlets 34 are provided so as to face each other. The cleaning gas inlet 34 is connected to the cleaning gas line L <b> 2, and a cleaning gas (plasma gas) is supplied into the chamber 11 through the cleaning gas inlet 34. As shown in FIG. 4, the cleaning gas inlet 34 is provided with a lid member 35 having a plurality of slits 35a, and the cleaning gas is introduced through the slits 35a. The lid member 35 is made of the same material as the chamber 11 such as aluminum. The lid member 35 flattens the wall surface of the chamber 11 and reduces the occurrence of abnormal discharge when plasma is generated.

  An exhaust port 36 is provided at the bottom of the chamber 11. The exhaust port 36 is connected to the exhaust line L3 via the valve V2. As described above, the TMP 13 and the APC 14 are provided in the exhaust line L3. By these operations, the chamber 11 is evacuated to a predetermined pressure atmosphere, for example, a pressure of 0.01 Pa or less.

  One end of the cleaning exhaust line L4 is connected between the exhaust side of the valve V2 and the intake side of the APC 14 in the exhaust line L3. The other end of the cleaning exhaust line L4 is configured as an exhaust pipe 37 provided in the upper electrode 26. The exhaust pipe 37 is connected to a diffusion portion 29a inside the upper electrode 26 (electrode support 29). That is, the cleaning exhaust line L4 has one end connected to the diffusion path inside the upper electrode 26 and the other end connected to the exhaust line L3. A valve V3 is provided on the exhaust side of the exhaust pipe 37. As will be described later, the cleaning exhaust line L4 is particularly provided for cleaning the upper electrode.

  Hereinafter, the operations of the plasma processing apparatus 10 during the film forming process and the cleaning process will be described with reference to FIG. The operation shown below is an example, and any operation may be used as long as the same effect can be obtained.

First, the wafer W is loaded into the chamber 11 and placed on the susceptor 17. The wafer W is fixed by an electrostatic chuck. Thereafter, the system controller 100 opens the valve VC and starts supplying O ₂ , and activates the second high-frequency power source 32 to apply RF power to the upper electrode 26. Subsequently, the valves VA, VB, and VD are opened, and SiF ₄ , SiH ₄ , and Ar are supplied into the chamber 11. Subsequently, the first high-frequency power source 22 is activated to apply power to the lower electrode (susceptor 17). Thereby, plasma of a process gas is generated, and a SiOF film is formed on the surface of the wafer W.

The system controller 100 turns off the application of RF power to the lower electrode after a predetermined time, and stops the supply of SiF ₄ , SiH ₄ and Ar to the chamber 11. Thereafter, the electrostatic chuck is released. The system controller 100 stops the supply of O ₂ and turns off the application of RF power to the upper electrode 26. Finally, the wafer W is unloaded from the chamber 11 and the film forming process is completed.

  The system controller 100 starts the cleaning process after the film forming process as described above is performed on the predetermined number of wafers W.

  First, a cleaning dummy wafer W is carried into the chamber 11 and placed on the susceptor 17. The dummy wafer W on the susceptor 17 is fixed by an electrostatic chuck. At this time, the system controller 100 closes the valve V1 connected to the process gas line L1 and the valve V2 connected to the exhaust line L3, while opening the valve V3 connected to the cleaning exhaust line L4. To do. As a result, an air supply / exhaust system including the cleaning gas line L2, the inside of the chamber 11, the cleaning exhaust line L4, and the TMP 13 is formed.

Subsequently, the system controller 100 starts supplying NF ₃ and Ar, and then turns on the plasma generator 12. The plasma generator 12 forms NF ₃ plasma, and selectively introduces fluorine radicals in the plasma into the chamber 11 from the cleaning gas inlet 34. The film made of SiOF or the like deposited and attached to the wall surface of the chamber 11, the susceptor 17 or the like is decomposed and removed by the cleaning gas.

  Here, the exhaust pipe 37 is connected to the diffusion portion 29 a inside the electrode support 29. That is, the cleaning exhaust line L4 is connected to the diffusion path (diffusion part 29a) in the upper electrode 26. The gas exhausted from the chamber 11 includes an unreacted cleaning gas in addition to the decomposition product. When such unreacted cleaning gas passes through the diffusion portion 29a and is exhausted from the exhaust pipe 37, it is exhausted while decomposing and removing the impurity film deposited on the gas holes 28a, the diffusion portion 29a and the like. It becomes.

  The upper electrode 26 includes fine gas holes 28 a and a diffusion portion 29 a, and the process gas tends to stay therein, so that deposits are most easily formed in the chamber 11.

  However, according to the configuration in which the cleaning exhaust line L4 leading to the diffusion path in the upper electrode 26 is provided and the cleaning gas is exhausted through the upper electrode 26 as in the present embodiment, the cleaning gas can be easily The electrode 26 can enter the inside of the electrode 26 and is exhausted out of the chamber 11 as it is. Therefore, it is possible to quickly and sufficiently clean the inside of the upper electrode 26 that is provided with a fine diffusion path or the like and in which deposits are most easily formed. Accordingly, the time required for the entire cleaning process is shortened, and the deterioration of other chamber members is reduced, so that a high yield and a high throughput are possible.

During the cleaning process, the system controller 100 monitors the progress of cleaning based on a predetermined end point detection method using pressure, optical data, and the like. When detecting the end point of cleaning, the system controller 100 turns off the plasma generator 12 and further stops the supply of the cleaning gas. Thereafter, O ₂ and Ar are supplied into the chamber 11. Subsequently, after the electrostatic chuck is released, the supply of O ₂ and Ar is stopped. Finally, the dummy wafer W is unloaded from the chamber 11 and the cleaning process ends.

  As described above, according to the present embodiment, by providing the cleaning exhaust line L4 connected to the diffusion path in the upper electrode 26, the deposit is most easily formed and is the most difficult to be cleaned. The inside of the electrode 26 can be cleaned in a short time and with high cleanliness. Thereby, it is possible to perform processing with high yield and high throughput while suppressing deterioration of other chamber members.

  The present invention is not limited to the above embodiment, and various modifications and applications are possible. Hereinafter, modifications of the above-described embodiment applicable to the present invention will be described.

  In the above embodiment, the cleaning is performed with the valve V2 leading to the exhaust line L3 closed. However, cleaning may be performed with the valve V2 opened. At this time, the cleaning gas introduced into the chamber 11 is exhausted from the exhaust line L3 connected to the exhaust port 36 and the cleaning exhaust line L4 connected to the exhaust pipe 37, thereby the upper electrode 26. In addition, the lower cleaning of the chamber 11 can be performed.

  Further, the system controller 100 may be configured to perform cleaning by combining cleaning using only the cleaning exhaust line L4 and cleaning using the exhaust line L3 and the cleaning exhaust line L4. For example, the system controller 100 may include a counter and perform cleaning using the exhaust line L3 each time cleaning is performed using only the cleaning exhaust line L4 several times.

  In the above example, the exhaust pipe 37 is connected to the diffusion portion 29a in the upper electrode 26, that is, the cleaning exhaust line L4 is connected to the diffusion portion 29a in the upper electrode 26. However, the position where the exhaust pipe 37 is provided is not limited to this. For example, the gas introduction pipe 30 for introducing the process gas may be connected so as to be branched. In this case, the cleaning exhaust line L4 may be connected to the exhaust side of the valve V1. As described above, the cleaning exhaust line L4 may be connected to the process gas line L1. Furthermore, the number of exhaust pipes 37 connected to the upper electrode 26 is not limited to one, and a plurality of exhaust pipes 37 may be provided.

  Furthermore, modifications as shown in the following (1) and (2) are also possible.

(1)
In the above embodiment, the lid 35 is provided at the remote plasma inlet in order to reduce abnormal discharge. However, instead of using the lid member 35 as described above, the cleaning gas inlet 34 and the vicinity thereof may have a structure using a valve body as shown in FIGS. 5 and 6, for example. 5 and 6 show a closed state and an open state of the cleaning gas inlet 34, respectively.

  As shown in FIG. 5, the cleaning gas inlet 34 is provided so as to penetrate the side wall of the chamber 11, and opens toward the outside of the chamber 11 and a first opening 34 a that opens toward the inside of the chamber 11. A second opening 34b. In the vicinity of the first opening 34a, a step is formed so as to surround it.

  In the side wall of the chamber 11 in the vicinity of the cleaning gas introduction port 34, a side tube 40 connected to the cleaning gas introduction port 34 substantially vertically is embedded. The side tube 40 is provided so as to be substantially parallel to the side wall of the chamber 11. Further, the side tube 40 bends substantially vertically in the middle and protrudes from the wall of the chamber 11, and is connected to a cleaning gas line L <b> 2 provided outside the chamber 11. The side tube 40 is made of a material having good plasma resistance such as resin or metal or the same material as the chamber 11. Instead of providing the side tube 40, a similar tubular hole may be formed in the side wall of the chamber 11.

  The cleaning gas inlet 34 is provided with a valve body 41 so as to embed the second opening 34b. The valve body 41 includes a lid body 42, a stem 43 that supports the lid body 42, a drive mechanism 44 connected to the stem 43, and a fixture 45.

  The lid 42 is made of the same material as the chamber 11, for example, aluminum. The lid 42 is formed in a convex disk shape and has a step on the periphery of the planar convex portion. The convex portion has an area substantially the same as or slightly smaller than that of the first opening 34a. The height of the convex portion is substantially the same as the distance between the side wall of the chamber 11 and the bottom surface of the step parallel to the side wall, and the lid 42 is fitted to the first opening 34a and the step surrounding the same. It is said that. That is, the lid 42 is formed in a state in which the main surface of the convex portion is substantially the same as the side wall of the surrounding chamber 11 in a state where the lid 42 is fitted in the first opening 34a (the cleaning gas inlet 34 is closed). It is formed to do. Further, the main surface of the lid body 42 including the convex portions is anodized.

  A first O-ring 46 is provided on one surface of the peripheral edge of the lid 42 so as to surround the convex portion. As shown in FIG. 5, the first O-ring 46 hermetically seals the first opening 34 a in a state where the lid 42 is fitted to the cleaning gas inlet 34. A second O-ring 47 is provided on the other surface of the lid 42 so as to face the first O-ring 46.

  The stem 43 is made of the same material as the chamber 11, for example, aluminum. A lid body 42 is provided at one end of the stem 43. The stem 43 is configured, for example, as a molded product integrated with the lid body 42. A disc-shaped bellows attachment portion 48 is formed in the middle of the stem 43 so as to surround the stem 43. Further, a connector portion 49 is provided on a portion of the stem 43 existing outside the chamber 11. The connector part 49 is comprised from the hollow cylindrical member which has a bottom face with a L-shaped cross section. A plate-like contact portion 49 a made of a general electrode member is provided on the inner wall of the cylindrical portion of the connector portion 49.

  The drive mechanism 44 is connected to the other end of the stem 43. The drive mechanism 44 is driven by an air cylinder, a motor, or the like, so that the lid body 42 and the stem 43 can advance and retract in the extending direction of the cleaning gas introduction port 34. The drive mechanism 44 is connected to the controller 100 and performs an opening / closing operation in accordance with an instruction from the controller 100.

  The fixture 45 is made of the same material as the chamber 11, for example, aluminum. The fixture 45 is formed of a hollow cylindrical member having a T-shaped cross section with a portion protruding outward. The fixing tool 45 is fitted into the second opening 34b of the cleaning gas inlet 34, and is fixed to the outer wall of the chamber 11 with a screw or the like at a portion protruding outward (center portion of the T shape).

  One end of the bellows 50 is attached to the end of the fixture 45 that is not fitted in the second opening 34b, and the other end of the bellows 50 is attached to the bellows attachment 48 of the stem 43. The bellows 50 is made of stainless steel or the like. The inner diameter of the cylindrical fixture 45 is set to be larger than the bellows attachment portion 48 of the stem 43. Thereby, the stem 43 and the bellows attachment portion 48 can advance and retreat inside the fixture 45 by the drive mechanism 44.

  The bellows 50 is provided so as to surround the stem 43 from the bellows attachment portion 48 of the stem 43 to the end of the fixture 45. By providing the bellows 50 in this manner, the airtightness inside and outside the chamber 11 is always maintained when the lid body 42 moves back and forth.

  A plate-like contact portion 45a made of a general electrode member is provided on the outer periphery of the end portion of the fixture 45 that is not fitted in the second opening 34b. The contact portion 49a of the fixture 45 is provided so as to contact the contact portion 45a of the connector portion 49 in the state shown in FIG. Thereby, in the closed state of the cleaning gas introduction port 34, the entire valve body 41 including the lid body 42 is set to a common potential (ground potential) with the chamber 11. Therefore, the generation of an unstable electric field in the vicinity of the lid 42 can be avoided, and the occurrence of abnormal discharge or the like can be prevented.

  As described above, the lid 42 can be advanced and retracted in the extending direction of the cleaning gas inlet 34 by the drive mechanism 44. By this advance / retreat operation, the valve body 41 opens and closes the cleaning gas introduction port 34 (first opening 34a). More specifically, the lid 42 opens and closes the cleaning gas inlet 34 between the first opening 34 a and the side tube 40.

  Here, in the opened state of the cleaning gas inlet 34 shown in FIG. 6, the lid 42 is in contact with the end of the fixture 45 on the inside of the chamber 11. At this time, the space between the lid 42 and the end of the fixture 45 is hermetically sealed by the second O-ring 47.

  From the cleaning gas line L2, the cleaning gas is introduced into the chamber 11 through the side tube 40 and the first opening 34a. At this time, the cleaning gas is introduced directly into the chamber 11, not through the slit 35 a or the like. For this reason, a decrease in the supply rate of the cleaning gas is reduced. In particular, a high cleaning gas supply rate into the upper electrode 26 is obtained, and a high cleaning rate is obtained. Further, the loss of radicals in the cleaning gas due to the passage of the slit 35a and the like can be avoided, and the cleaning gas activity is kept high, so that a higher cleaning speed can be obtained.

  At this time, the second O-ring 47 prevents the cleaning gas from entering the fixture 45 and prevents the bellows from being deteriorated by the cleaning gas.

  As described above, according to the configuration in which the so-called angle valve type valve element 41 is provided, the cleaning gas can be supplied into the chamber 11 without passing through the slit 35a or the like. The lid body 42 of the valve body 41 is provided so that its internal exposed surface forms substantially the same plane as the side wall of the chamber 11 in a state of being fitted to the first opening 34 a. As a result, abnormal discharge during plasma processing can be reduced, and the cleaning gas supply port 34 can be made larger to increase the supply rate of the cleaning gas.

  The supplied cleaning gas is supplied into the chamber 11 without passing through the slit 35a or the like. For this reason, a high cleaning gas supply rate can be obtained, and radical loss can be reduced. Thereby, a high cleaning speed and efficiency can be obtained, and the cleaning process can be shortened and the throughput can be improved.

The structure of the valve body 41 is not limited to the above structure, and abnormal discharge is prevented, a large opening of the cleaning gas inlet 34 is obtained, and the cleaning gas has a high activity without using the slit 35a or the like. Any structure that can be supplied into the chamber 11 may be used.
In the above example, the side tube 40 is provided inside the wall of the chamber 11. However, the side tube 40 is provided outside the chamber 11, and the side tube 40 and the valve body 41 are connected outside the chamber 11. It is good also as a structure.

  Furthermore, the sealing structure may be another sealing structure such as a labyrinth seal in addition to the O-ring.

(2)
In the above embodiment, as shown in FIG. 3, two cleaning gas inlets 34 are provided so as to face each other, and a lid member 35 having a large number of slits 35a as shown in FIG. 4 is provided. However, as shown in FIG. 7, the cleaning gas inlet 34 is divided into a plurality of parts so as to have the same opening area as a whole, and the slits 35a ′ of the lid member 35 ′ provided in each cleaning gas inlet 34 ′ are densely arranged. An arrangement may be adopted.

  In FIG. 7, the chamber 11 includes three or more, for example, six cleaning gas inlets 34 connected to the cleaning gas line L2. The cleaning gas inlet 34 is provided at substantially the same height (slightly above the susceptor 17). Each cleaning gas inlet 34 is provided with a lid member 35 as shown in FIG. 8, and the cleaning gas is supplied into the chamber 11 through the lid member 35.

  In FIG. 7, three cleaning gas inlets 34 ′ are formed so as to face each other, a total of six. Here, the opening area of the entire cleaning gas introduction port 34 ′ is configured to be substantially the same as the configuration in which the two cleaning gas introduction ports 34 shown in FIG. 3 are provided.

  Further, the lid member 35 ′ provided in the cleaning gas inlet 34 ′ shown in FIG. 7 is formed so as to have substantially the same number of slits 35 a ′ as the whole lid member 35 shown in FIG. 3. In other words, in the configuration shown in FIG. 7, the slit 35 a ′ is densely integrated and formed in the lid member 35 ′ than in the configuration shown in FIG. 3. As described above, the configuration in which the slits 35 a ′ are integrated makes it possible to suppress interference between the gases that have passed through the adjacent slits 35 a ′, and the cleaning gas supply speed is maintained high even in the central portion of the chamber 11.

  9 (a) and 9 (b) are the same in the configuration in which two cleaning gas introduction ports 34 shown in FIG. 3 are provided and the configuration in which six cleaning gas introduction ports 34 ′ are provided as shown in FIG. The flow velocity distribution at the time of introducing the cleaning gas at a flow rate is schematically shown. 9 (a) and 9 (b), the flow velocity distribution is shown in three stages with a one-dot chain line, and each stage is assumed to have substantially the same flow velocity in FIGS. 9 (a) and 9 (b).

  As shown in FIG. 9A, in the configuration using the cleaning gas inlet 34 provided with the slits 35a relatively sparsely, the flow velocity distribution of the cleaning gas is relatively gentle over the entire cleaning gas inlet 34. It has become a thing. On the other hand, as shown in FIG. 9B, in the configuration using the cleaning gas inlet 34 ′ in which the slits 35a ′ are relatively densely distributed, the flow velocity distribution becomes relatively steep, and a region having a high flow velocity is present. The center of the chamber 11 can be reached.

  That is, in the configuration in which the slits 35a are distributed over a relatively wide range, the gas that has passed through the slits 35a is likely to diffuse. For this reason, as shown to Fig.10 (a), the resistance (interference) by the collision of diffusion components is comparatively large. On the other hand, in the configuration in which the slits 35a 'are distributed relatively densely, as shown in FIG. 10B, the resistance (interference) due to collision between the diffusion components is relatively small.

  Therefore, when comparing the flow velocity P0 of the gas immediately after passage with the flow velocity P1 at a predetermined point after passage, in the configuration shown in FIG. 10A in which the slits 35a are provided relatively sparsely, P1 is more than P0. A relatively large decrease (P0 >> P1). On the other hand, in the configuration shown in FIG. 10B in which the slits 35a 'are provided relatively sparsely, the decrease in P1 is relatively small (P0 ≧ P1).

  As described above, by providing the slits 35 a ′ relatively densely, a decrease in the flow rate due to interference between adjacent gas flows is suppressed, and a high gas supply rate can be obtained even in the central portion of the chamber 11. As a result, the cleaning gas can easily enter the upper electrode 26, the cleaning speed of the upper electrode 26 can be improved, and shortened and highly efficient cleaning can be performed.

  The cleaning gas inlet 34 having a relatively small diameter may be provided with a predetermined inclination so as to face the lower surface of the upper electrode 26 (electrode plate 28). As a result, the cleaning gas can easily enter the upper electrode 26, and more efficient cleaning can be performed. Further, the cleaning gas inlets 34 do not have to be arranged at the same height, and a plurality of cleaning gas inlets directed toward the upper electrode 26 or toward the susceptor 17 may be provided.

  Further, the number of cleaning gas inlets 34 is not limited to the above example, and any number may be provided as long as efficient cleaning is possible. Further, the shape and the number of the slits 35 a included in the lid member 35 are not limited to the above example, and may be set as desired according to the shape, the number, and the like of the cleaning gas inlet 34. Moreover, it is good also as a round hole etc. instead of the slit 35a. Furthermore, the slit 35a of the lid member 35 may be formed in a tapered shape as shown in FIG.

  Further, by adjusting the size of the opening of the cleaning gas inlet, the number of slits 35a formed in the lid member 35, the opening area of the slit 35a, the distance to the flow direction of the slit 35a (the thickness of the lid member 35), etc. Of course, a high cleaning gas supply rate can be obtained.

  In the above embodiment, the cleaning gas is activated so as to generate plasma, particularly radicals in the plasma. However, cleaning may be performed by generating active species other than radicals by activating the cleaning gas.

In the above embodiment, the parallel plate type plasma CVD apparatus is used to form the SiOF film on the wafer W and perform cleaning with NF ₃ gas. However, the film to be formed is not limited to SiOF, and may be a silicon-based film such as SiO ₂ , SiC, SiN, SiCN, SiCH, or SiOCH. The cleaning gas is not limited to NF ₃ , and fluorine-based gases such as CF ₄ , C ₂ F ₆ , and SF ₆ , and chlorine-based gases such as Cl ₂ and BCl ₄ can be used. Further, the object to be processed is not limited to a semiconductor wafer but may be a liquid crystal display device or the like.

  Furthermore, the present invention is not limited to the parallel plate type, but can be applied to other plasma processing apparatuses such as an ECR (Electron Cyclotron Resonance) type, an ICP (Inductive Coupled Plasma) type, and a helicon type. Further, the present invention is not limited to the plasma CVD apparatus, and can be applied to other apparatuses using plasma such as an etching apparatus, a sputtering apparatus, and an annealing apparatus.

It is a figure which shows the structure of the plasma processing apparatus concerning embodiment of this invention. It is a figure which shows the cross-sectional structure of the plasma processing apparatus shown in FIG. It is a figure which shows the cross-sectional structure of the chamber shown in FIG. It is a figure which shows the cover material concerning this Embodiment. It is a figure which shows the structure of the valve body concerning other embodiment of this invention. It is a figure which shows the structure of the valve body concerning other embodiment of this invention. It is a figure which shows the cross-sectional structure of the chamber concerning other embodiment of this invention. It is a figure which shows the structure of the cover material concerning other embodiment of this invention. It is the schematic which shows the flow-velocity distribution at the time of using the cover material concerning other embodiment of this invention. It is a figure which shows the change of the flow rate typically. It is a figure which shows the structure of the cover material concerning other embodiment of this invention. It is a figure which shows the cross-sectional structure of the conventional plasma CVD apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Plasma processing apparatus 11 Chamber 12 Plasma generator 17 Susceptor 26 Upper electrode 28 Electrode plate 29 Electrode support body 29a Diffusion part 34 Cleaning gas inlet 35 Cover material 37 Exhaust pipe 100 System controller L1 Process gas line L2 Cleaning gas line L3 Exhaust line L4 Cleaning exhaust line

Claims (8)

A chamber;
A cleaning gas line for supplying a cleaning gas for cleaning the inside of the chamber into the chamber;
A gas activation means disposed in the cleaning gas line and activating the cleaning gas;
The cleaning gas that is provided on the wall of the chamber and is activated by the gas activating means passes through a plurality of slits that are densely formed so that interference of gas passing through adjacent slits is suppressed, A gas inlet supplied into the chamber;
A plasma processing apparatus comprising: A process gas line for supplying a predetermined process gas into the chamber;
A diffusion path connected to the process gas line for diffusing the process gas introduced from the process gas line, and the process gas connected to the diffusion path and diffused by the diffusion path are supplied into the chamber. A diffusion electrode having a plurality of gas holes and capable of applying high-frequency power;
A cleaning gas exhaust line that has one end connected to at least one of the process gas line and the diffusion path, the other end connected to an exhaust means, and exhausts the cleaning gas from within the chamber. The plasma processing apparatus according to claim 1.   The process gas exhaust line for exhausting the process gas introduced into the chamber from the process gas line is provided, and the process gas exhaust line is exhausted by exhaust means. Plasma processing equipment.   The chamber includes an exhaust port, the process gas exhaust line includes a valve provided between the exhaust unit and the exhaust port, and the other end of the cleaning gas exhaust line is the valve of the process gas exhaust line. 4. The apparatus according to claim 3, wherein the exhaust unit exhausts the chamber through the cleaning gas exhaust line in a state where the exhaust unit is connected to the exhaust unit and the valve is closed. Plasma processing equipment.   The plasma processing apparatus according to claim 1, wherein the gas activation unit generates plasma of the cleaning gas. A chamber, a cleaning gas line for supplying a cleaning gas for cleaning the inside of the chamber into the chamber, and a gas activation means disposed in the cleaning gas line and activating the cleaning gas. A plasma processing apparatus cleaning method comprising:
Introducing the cleaning gas activated by the gas activating means into the chamber through a plurality of slits formed densely so as to suppress interference of gas passing through adjacent slits; ,
And a evacuation step of exhausting the cleaning gas introduced into the chamber from the chamber.   The plasma processing apparatus is provided with a process gas exhaust means for exhausting the process gas introduced into the chamber, and in the exhaust process, the process gas exhaust means exhausts the process gas. The method for cleaning a plasma processing apparatus according to claim 6.   The plasma processing apparatus includes a valve provided between the process gas exhaust means and the exhaust port of the chamber. In the exhaust process, the chamber is exhausted with the valve closed. The method for cleaning a plasma processing apparatus according to claim 6 or 7, wherein:

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