JP5324026B2 - Plasma processing apparatus and plasma processing apparatus control method - Google Patents

Abstract

A method for fabricating a semiconductor device is provided to improve the production yield of the semiconductor device by allowing a moving speed of an etchant nozzle to be dependent on a film thickness distribution. An insulating film(11) for forming sidewall insulating films of a gate electrode is deposited on a main surface of a semiconductor wafer(1). Then, the treatment for equalizing the film thickness distribution of the insulating film is performed. In this treatment, the semiconductor wafer is fixed onto a spin stage(32) of an etching apparatus(31) and rotated. An etchant(37) is supplied from an etchant nozzle(36) onto the main surface of the rotated semiconductor wafer while the etchant nozzle is moved from the peripheral side of the main surface of the semiconductor wafer to its central side. The moving speed of the etchant nozzle is controlled depending on the film thickness distribution of the insulating film so that the moving speed in a region with a larger rate of film thickness of the insulating film in a radial direction of the semiconductor wafer is smaller than that in a region with a smaller rate of film thickness.

Description

  The present invention relates to a plasma processing apparatus for plasma processing an object to be processed and a control method for the plasma processing apparatus. In particular, the present invention relates to the formation of a coating on the inner wall of the chamber.

  2. Description of the Related Art Various plasma processing apparatuses have been developed in which a processing gas supplied into a chamber is turned into plasma and a substrate is plasma processed. Among these, the microwave plasma CVD apparatus ionizes and dissociates the processing gas with the power of the microwave, thereby converting the processing gas into plasma and forming a film on the substrate.

In this plasma process, for example, when a SiO _x film such as SiO ₂ is formed, SiH ₄ gas is generally used as a processing gas. When SiH ₄ gas is used for film formation, a SiO _x film adheres to the inner wall of the chamber. This SiO _x film is heated when the substrate is formed, and cooled when being transferred to / from the load lock chamber. When heating and cooling are repeated in this manner, distortion occurs between the deposit and the chamber wall due to the difference in thermal expansion coefficient between the deposit on the inner wall of the chamber and the member constituting the chamber. As a result, when the deposit reaches a certain thickness, the deposit peels off from the chamber wall, falls as particles on the substrate, and mixes with the thin film during film formation to deteriorate the film quality.

In order to suppress the generation of such particles, it is necessary to clean the chamber when the deposit reaches a predetermined thickness, and to remove the SiO _x film adhering to the inner wall of the chamber. For this reason, the microwave plasma CVD apparatus supplies a fluorine (F) -based gas (for example, CF ₄ ), which is a cleaning gas, instead of a processing gas at the time of cleaning and generates plasma. F radicals in the generated plasma attack the SiOx film attached to the inner wall of the chamber. As a result, Si in the SiOx film is discharged out of the chamber as SiFx (SiF ₁ , SiF ₂ , SiF ₃ , SiF ₄ ) gas. The remaining Ox in the SiOx film reacts with C and is discharged out of the chamber as CO or CO ₂ gas.

However, as described above, plasma of an F-based gas is used for cleaning the plasma CVD apparatus, and the chamber body is made of Al and the ceiling portion is made of Al ₂ O ₃ . In such a situation, when F ions in the chamber attack Al ₂ O ₃ , the bond between Al—O is broken and a film of Al—F or the like is partially generated. Here, the binding energy of Al—F is 159 kcal / mol, and the binding state is stable as in Al ₂ O ₃ where the binding energy of Al—O is 120 kcal / mol. As a result, during cleaning, Al in the chamber body and Al ₂ O _{3 in the} ceiling portion may be fluorinated, and the chamber inner wall and ceiling portion may partially become AlF. In addition, since the combined state of SiF ₄ and F ₂ generated during cleaning is stable, some of them may not be discharged out of the chamber and may be physically adsorbed on the inner wall of the chamber.

Partially fluorinated AlF may be released into the chamber as F due to the breakage of the Al-F bond by the action of ions during film formation. In addition, SiF ₄ and F ₂ adsorbed on the inner wall of the chamber are easily desorbed because the adsorption energy is small. As a result, there arises a problem that the F-based residue existing in the chamber is desorbed and mixed into the thin film being formed.

  In addition, in order to increase the yield of products during film formation and to manufacture products stably, the supply of radicals into the processing chamber, the formation of thin films in the processing chamber, and the exhaust of gases outside the processing chamber are usually performed. It is necessary to make a series of circulations in a steady state before depositing the object to be processed. That is, by setting the process conditions to be the same as those at the time of film formation before film formation, it is necessary to perform stable film formation without causing radicals generated during the process to be consumed on the inner wall of the chamber.

As described above, the problem that F desorption from Al-F and the like existing on the inner wall of the chamber and desorption of SiF ₄ and F ₂ from the inner wall of the chamber cause the deterioration of the film quality is solved. From the viewpoint of setting the process conditions to the same as those at the time of film formation before film formation, the same gas as that supplied at the time of film formation after cleaning and before film formation (that is, at the time of so-called precoat film formation) is plasma. Thus, a technique for coating the inner wall surface of the chamber with the plasma (that is, forming a so-called precoat film) has been widely known (see, for example, Patent Document 1).
JP-A-11-340149

  Incidentally, a baffle plate is generally provided in a plasma processing apparatus in order to adjust the flow of radicals (hereinafter referred to as deposition radicals) that contribute to film formation in a chamber to a preferable state. The conductance of the baffle plate is set to be small (that is, it is difficult for gas to flow) in order to perform good plasma processing on the substrate during film formation. Therefore, at the time of film formation, the processing chamber and the exhaust chamber are partitioned by the baffle plate, and the pressure difference between the chambers is large (see (A: no gap) in FIG. 4). Thereby, even when the precoat film is formed, the pressure difference between the processing chamber and the exhaust chamber remains large.

On the other hand, the deposition rate DR (Deposition Rate) of the film formed on the inner wall of the chamber is expressed by the following equation (1).
DR = k × P (1)
Here, k is a proportionality constant and P is a pressure.

  According to FIG. 4A, since the processing chamber pressure P1 is higher than the exhaust chamber pressure P2, the deposition rate DR1 of the processing chamber is faster than the deposition rate DR2 of the exhaust chamber. As a result, the precoat film formed on the inner wall surface of the processing chamber is thicker than the precoat film formed on the inner wall surface of the exhaust chamber.

  Further, in practice, the gas is supplied to the processing chamber and preferentially used in the processing chamber to form the precoat film, so that the residual amount of gas (radical) flowing to the exhaust chamber side is reduced. Considering this, the difference in the precoat film between the processing chamber and the exhaust chamber is considered to be larger than the theoretical value derived from the equation (1).

  As a result, when the precoat film is formed on the inner wall surface of the processing chamber to a thickness that does not cause desorption of F-based residues that cause film quality deterioration, the precoat film formed on the inner wall surface of the exhaust chamber is formed. Since the membrane is still thin, it is not possible to suppress detachment of F-based residues existing on the inner wall surface of the exhaust chamber. As a result, there has been a problem that the F-based residue desorbed in the exhaust chamber during the process treatment rises to the treatment chamber and degrades the film quality.

  On the other hand, when the precoat film is formed on the inner wall surface of the exhaust chamber to such a thickness that F-based residues are not desorbed, the precoat film on the inner wall surface of the processing chamber becomes thicker than necessary. As a result, the thickness of the deposit that accumulates on the inner wall of the chamber during the process quickly reaches the thickness of the film peeling, resulting in a shorter cycle (interval) for cleaning the chamber, lowering the throughput and lowering the productivity. There was a problem.

  In order to solve the above problems, the present invention provides a plasma processing apparatus and a plasma processing apparatus control method for coating the inner wall of the chamber with a more uniform thickness.

In order to solve the above problems, according to an aspect of the present invention, a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas. A plasma processing apparatus having a control device for controlling the mounting table, and when forming a precoat film on the inner wall surface of the chamber, the pressure of the processing chamber and the pressure of the exhaust chamber are close to each other. By changing the position of the mounting table relative to the baffle plate with the control device, a plasma processing apparatus is provided that changes the aperture ratio between the mounting table and the chamber side wall.

  According to this, at the time of forming the precoat film on the inner wall surface of the chamber, at least one of the mounting table and the baffle plate is controlled so that the pressure in the processing chamber and the pressure in the exhaust chamber are close to each other. When the pressure difference between the processing chamber and the exhaust chamber is reduced, the difference between the deposition rate DR1 of the processing chamber and the deposition rate DR2 of the exhaust chamber obtained from the equation (1) is reduced. As a result, the deposit radical in the processing chamber can be brought into substantially the same state as the deposit radical in the exhaust chamber. As a result, the film thickness of the precoat film formed in the processing chamber and the film thickness of the precoat film formed in the exhaust chamber can be made more equal, and the film quality can be uniformly formed. Thereby, not only can the precoat film formation time be greatly shortened, but also the cycle until the inside of the chamber is cleaned can be lengthened. As a result, throughput can be improved and productivity can be increased.

As an example of controlling the mounting table so as to reduce the pressure difference between the processing chamber and the exhaust chamber in this way, an elevating mechanism for raising and lowering the mounting table is provided, a baffle plate is fixed to the inner wall of the chamber, and a precoat film There is a method of raising and lowering the mounting table by the control device so that the opening ratio between the mounting table and the chamber side wall at the time of formation is larger than the opening ratio at the time of the process.

  According to this, the distance between the mounting table and the baffle plate is adjusted to be different between the precoat film formation and the process. That is, during the process, the mounting table is moved up and down so that the distance between the mounting table and the baffle plate is reduced. As a result, the processing chamber is maintained at a pressure that matches the process conditions. As a result, deposition radicals are confined in the processing chamber, so that the film forming speed is high and the film can be formed with high uniformity. On the other hand, when the precoat film is formed, the mounting table is moved up and down so as to leave a space between the mounting table and the baffle plate. As a result, gas easily flows from the processing chamber to the exhaust chamber, and the pressure difference between the processing chamber and the exhaust chamber is reduced. As a result, the deposition radicals in the processing chamber can be brought into substantially the same state as the deposition radicals in the exhaust chamber. As a result, the film thicknesses of the precoat film in the processing chamber and the precoat film in the exhaust chamber can be made equal, and the film quality can be uniformly formed.

In addition, as another example of controlling the mounting table so that the pressure difference between the processing chamber and the exhaust chamber is reduced, the mounting table is provided with a lifting mechanism for moving the mounting table up and down , and the baffle plate is attached to either the chamber or the mounting table. forming a pre-coating film to removably fixed, when the plasma processing a workpiece is fixed to the baffle plate to the mounting table while make lifting the mounting table in the control device, the inner wall surface of the chamber by fixing the baffle plate while causing lifting the mounting table in the chamber in the control device when the plasma the aperture ratio is the object to be processed in forming the pre-coat layer on the inner wall surface of the chamber The method of adjusting the space | interval of the said mounting base and the said baffle board so that it may become larger than the said aperture ratio at the time of processing is mentioned.

  According to this, in consideration of the fact that the positional relationship between the mounting table and the baffle plate affects the accuracy of the plasma processing, the baffle plate is fixed to the mounting table side and raised together with the mounting table during the process. The baffle plate can be moved to the optimum position for processing. That is, by effectively confining radicals in the processing chamber by the baffle plate, it is possible to increase the deposition rate on the object to be processed and to form a uniform film on the object to be processed. On the other hand, when the precoat film is formed, the baffle plate is fixed to the chamber side and the space between the mounting table and the baffle plate is kept, so that the depot radicals in the processing chamber are almost the same as the depo radicals in the exhaust chamber. The difference in film formation rate between the chamber and the exhaust chamber can be reduced, so that the film thicknesses of the precoat films in the processing chamber and the exhaust chamber can be made equal and the film quality can be uniformly formed.

According to another aspect of the present invention, a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas. The baffle plate has one or more through holes and an opening / closing mechanism for adjusting the opening degree of the through holes, and includes a control device for controlling the opening / closing mechanism, and is provided on the inner wall surface of the chamber. The precoat film is formed on the inner wall surface of the chamber by controlling the opening / closing mechanism of the baffle plate with the control device so that the pressure in the processing chamber and the pressure in the exhaust chamber approach each other when forming the precoat film. There is provided a plasma processing apparatus that adjusts the opening degree of the one or more through holes so that the aperture ratio of the through holes when performing the treatment is larger than the aperture ratio when performing plasma processing on the workpiece.

  According to this, during the process, the opening / closing mechanism is controlled so that the opening degree of the through hole of the baffle plate is reduced. As a result, the processing chamber is maintained at a pressure that matches the process conditions, and the deposition radicals are confined in the processing chamber, whereby a uniform film can be formed at a high film formation speed. On the other hand, when the precoat film is formed, the opening / closing mechanism is controlled so that the opening degree of the through hole provided in the baffle plate is increased. As a result, the pressure difference between the processing chamber and the exhaust chamber is reduced, and the deposit radicals in the processing chamber can be brought into substantially the same state as the deposit radicals in the exhaust chamber. As a result, the difference in film formation rate between the processing chamber and the exhaust chamber is reduced, the film thicknesses of the precoat films in the processing chamber and the exhaust chamber can be made equal, and the film quality can be uniformly formed.

According to another aspect of the present invention, a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas. And the outside of the chamber is provided with a radical generator for generating radicals that promote the formation of a precoat film on the inner wall surface of the chamber, and a transport pipe for connecting the exhaust chamber and the radical generator is provided, A plasma processing apparatus comprising: a control device that controls the radical to be supplied to the exhaust chamber through the transfer pipe after the chamber is cleaned.

  In general, a gas for forming a precoat film is supplied to a processing chamber, and the generated deposit radicals in the plasma are preferentially used for forming the precoat film in the processing chamber. As a result, the amount of gas (depot radical) remaining in the exhaust chamber is reduced. However, in the present invention, after the cleaning, the deposit radical is separately supplied to the exhaust chamber. This promotes the formation of the precoat film in the exhaust chamber. As a result, the precoat films in the processing chamber and the exhaust chamber can be formed with substantially the same film thickness and more uniform film quality.

Also, the radical generator is a remote plasma comprising a processing chamber formed by a dielectric, by the control device, so that the radicals are produced by plasma gas supplied to the processing container It may be controlled . Further, by the control device may be controlled such that the radicals are produced by the same gas and gas supplied when performing the plasma treatment to the object to be processed is supplied to the remote plasma.

  According to this, for example, when the process is a CVD (Chemical Vapor Deposition) process, the gas supplied when forming the precoat film is the same as the gas supplied during the process. Thereby, the precoat film becomes the same film as the film formed on the substrate. According to this, the process conditions can be set to the same conditions as during film formation before film formation. As a result, radicals generated during the process are not consumed on the inner wall of the chamber, so that stable and high-quality film formation is possible.

The plasma processing apparatus, the control apparatus, the microwaves transmitted through the dielectric through a slot by plasma processing gas supplied into the said chamber, is controlled to perform a plasma process on a target object A microwave plasma processing apparatus may be used.

Further, the dielectric of the microwave plasma processing apparatus is composed of a plurality of dielectric parts, and each dielectric part is provided with one or two or more slots, and the control device is provided with the one or two or more slots. The processing gas supplied into the chamber may be turned into plasma by microwaves that have passed through the slots and passed through the dielectric parts, and the object to be processed may be controlled to be subjected to plasma processing .

  According to this, each dielectric part is provided with a slot, and the area of each dielectric part is significantly smaller than in the prior art. Therefore, by transmitting microwaves to each dielectric part, Surface waves can be propagated uniformly on the surface of the part. As a result, the process window can be widened and plasma processing can be performed accurately and stably. In addition, because the dielectric window can be configured with each dielectric part reduced in size and weight, a microwave plasma processing apparatus can be manufactured easily and at low cost, and the area to be processed can be increased. On the other hand, it can respond flexibly.

According to another aspect of the present invention, a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas. a control method, when performing plasma processing on a processing target, and lifting the on the mounting table to the first position, when the pre-coating film formed on the inner wall surface of the cleaning time and the chambers of the chamber, forming a pre-coating film The upper table is moved up and down to a second position for making the interval between the upper table and the baffle plate larger than the distance between the upper table and the baffle plate when the object to be processed is plasma-treated. A method for controlling a plasma processing apparatus is provided.

  According to this, at the time of the process, by raising and lowering the mounting table to a predetermined position, the processing chamber is maintained at a pressure that matches the process conditions, and the deposition radicals are confined in the processing chamber. , A uniform film can be formed. On the other hand, when the chamber is cleaned or after cleaning, the pressure difference between the processing chamber and the exhaust chamber can be reduced by raising and lowering the mounting table to provide a space between the mounting table and the baffle plate. As a result, the film thickness of the precoat film in the processing chamber and the exhaust chamber is reduced by making the deposition radical in the processing chamber substantially the same as the state of the deposition radical in the exhaust chamber and reducing the difference in film formation rate between the processing chamber and the exhaust chamber. More uniform and uniform film quality can be formed. As a result, not only can the precoat film formation time be significantly shortened, but also the cycle until the chamber is cleaned can be lengthened. As a result, throughput can be improved and productivity can be increased.

According to another aspect of the present invention, there is provided a processing chamber for performing plasma processing on an object to be processed by a baffle plate having one or more through holes and an opening / closing mechanism for opening and closing the through holes and a mounting table; a method for controlling a plasma processing apparatus having a chamber which is partitioned into an exhaust chamber for exhausting gas, when plasma processing a workpiece, and sliding the opening and closing mechanism to the first position, the cleaning of the chamber When the precoat film is formed on the inner wall surface of the chamber and when the precoat film is formed, the opening of the through hole is larger than the opening of the through hole when the object to be processed is plasma-treated . A method of controlling a plasma processing apparatus that slides the opening / closing mechanism to position 2 is provided.

  According to this, during the process, the opening and closing mechanism is controlled so that the opening of the through hole of the baffle plate is reduced, so that the processing chamber is maintained at a pressure that matches the process conditions, and the depot radicals are confined in the processing chamber. Therefore, a uniform film can be formed with a high film formation speed. On the other hand, when the precoat film is formed, the opening / closing mechanism is controlled so that the opening of the through hole provided in the baffle plate is increased, thereby reducing the pressure difference between the processing chamber and the exhaust chamber and exhausting the depot radicals in the processing chamber. The film thickness of the precoat film in the processing chamber and the exhaust chamber can be made equal and the film quality can be made uniform by reducing the difference in the film formation rate between the chambers and reducing the difference in the film formation rate between the chambers. Can do.

According to another aspect of the present invention, a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas. And a control method for a plasma processing apparatus for supplying radicals for promoting the formation of a precoat film on the inner wall surface of the chamber to the exhaust chamber after the chamber is cleaned.

  According to this, formation of a precoat film in the exhaust chamber is promoted by radicals supplied to the exhaust chamber after cleaning. As a result, the precoat films of the processing chamber and the exhaust chamber can be formed with a more uniform film quality and substantially the same thickness.

  As described above, according to the present invention, it is possible to provide a plasma processing apparatus that coats the inner wall surface of the chamber with a more uniform thickness and a control method for the plasma processing apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

In this specification, 1 mTorr is (10 ⁻³ × 101325/760) Pa, and 1 sccm is (10 ⁻⁶ / 60) m ³ / sec.

(First embodiment)
(Configuration of microwave plasma processing equipment)
First, regarding the configuration of the microwave plasma processing apparatus according to the first embodiment of the present invention, FIG. 1, which is a cross-sectional view of the apparatus cut in the longitudinal direction (direction perpendicular to the y-axis), and the processing chamber of the apparatus 2 will be described with reference to FIG. In the following description, a gate oxide film forming process using the microwave plasma processing apparatus according to the present embodiment will be described as an example.

  The microwave plasma processing apparatus 100 has a housing composed of a chamber 10 and a lid 20. The chamber 10 has a bottomed cubic rectangular parallelepiped shape whose upper part is opened, and is grounded. The chamber 10 is made of, for example, a metal such as aluminum (Al).

  Inside the chamber 10, a susceptor 11 (mounting table) on which an object to be processed such as a substrate G is mounted is provided at substantially the center. The susceptor 11 is made of aluminum nitride, for example.

  Inside the susceptor 11, a power feeding unit 11a and a heater 11b are provided. A high frequency power supply 12b is connected to the power supply unit 11a via a matching unit 12a (for example, a capacitor). In addition, a high-voltage DC power supply 13b is connected to the power supply unit 11a via a coil 13a. The matching unit 12a, the high frequency power source 12b, the coil 13a, and the high voltage DC power source 13b are provided outside the chamber 10, and the high frequency power source 12b and the high voltage DC power source 13b are grounded.

  The power feeding unit 11a applies a predetermined bias voltage to the inside of the chamber 10 by the high frequency power output from the high frequency power source 12b. The power feeding unit 11a electrostatically attracts the substrate G with a DC voltage output from the high-voltage DC power supply 13b.

  An AC power supply 14 provided outside the chamber 10 is connected to the heater 11b, and the substrate G is held at a predetermined temperature by an AC voltage output from the AC power supply 14.

  The bottom surface of the chamber 10 is opened in a cylindrical shape, and one end of the bellows 15 is attached to the outer wall surface of the chamber 10 in the vicinity of the opened outer periphery. A lifting plate 16 is fixed to the other end of the bellows 15. In this way, the opening at the bottom of the chamber 10 is sealed by the bellows 15 and the lifting plate 16.

  The susceptor 11 is supported by a cylinder 17 disposed on the elevating plate 16 and moves up and down integrally with the elevating plate 16 and the cylinder 17 by a driving force output from the electric motor 16a. In this manner, the electric motor 16a adjusts the susceptor 11 to a desired height.

  A baffle plate 18 is provided around the susceptor 11 to control the gas flow in the chamber 10 to a preferable state. The interior of the chamber 10 is partitioned by a susceptor 11 and a baffle plate 18 into a processing chamber 10u for plasma processing the substrate G and an exhaust chamber 10d for exhausting gas. Further, on the inner wall side portion of the chamber 10, a receiving tool 18 a that protrudes toward the susceptor 11 at a substantially center is provided. The baffle plate 18 is fixed to the inner wall side portion of the chamber 10 by being supported by the receiving member 18a at the outer peripheral edge of the lower surface thereof.

  The chamber 10 is provided with a dry pump 19a, an APC (Automatic Pressure Control) 19b, and a TMP (Turbo Molecular Pump) 19c as the exhaust mechanism 19.

  The dry pump 19a opens and closes a predetermined valve to roughen the gas until the inside of the chamber 10 reaches a predetermined reduced pressure state, and then switches between opening and closing the valve to reduce the back pressure of the TMP 19c. The APC 19b is provided with a valve body that controls the communication state between the exhaust chamber 10d and the TMP 19c. By sliding the valve body of the APC 19b in accordance with the change in the pressure P1 in the processing chamber 10u, the APC 19b The communication portion with the TMP 19c has a desired opening. Thereby, the atmosphere in the chamber 10 is depressurized to a predetermined degree of vacuum according to the opening degree of the valve body of the APC 19b.

  The lid 20 is disposed so as to seal the upper part of the chamber 10. Similar to the chamber 10, the lid 20 is made of a metal that is a nonmagnetic material such as aluminum (Al). The lid 20 is provided with a lid main body 21, a waveguide 22a to a waveguide 22f, a slot antenna 23a to a slot antenna 23f, a dielectric composed of a dielectric part 24a to a dielectric part 24f, and a beam 25. It has been.

  The chamber 10 and the lid body 20 are fixed by an O-ring 26 disposed between the lower surface outer peripheral portion of the lid main body 21 and the upper surface outer peripheral portion of the chamber 10, thereby maintaining the airtightness in the chamber. .

  As shown in FIG. 2, the waveguides 22a to 22f formed on the lower surface of the lid main body 21 are arranged in parallel with each other in the y-axis direction. The waveguide 22a and the waveguide 22b, the waveguide 22c and the waveguide 22d, the waveguide 22e and the waveguide 22f include a branched waveguide 27a having a V-shape in plan view at the ends thereof. A branch waveguide 27b and a branch waveguide 27c are connected to each other. A microwave generator 28 is connected to each branch waveguide 27.

Each waveguide 22 is formed of a rectangular waveguide whose cross section perpendicular to the axial direction is rectangular. For example, in the TE10 mode (TE wave: transverse electric wave), the long-side tube wall of the cross section perpendicular to the axial direction of each waveguide 22 is parallel to the magnetic field. The tube wall in the short side direction becomes an E surface parallel to the electric field. The arrangement of the long side direction and the short side direction of each waveguide varies depending on the mode (electromagnetic field distribution in the waveguide). The inside of each waveguide 22 and each branch waveguide 27 is filled with a dielectric member such as alumina (aluminum oxide: Al ₂ O ₃ ), quartz, fluorine resin, or the like. The dielectric member controls the in-tube wavelength λg ₁ of each waveguide 22 according to the formula λg ₁ = λc / (εε ₁ ) ^1/2 . Here, λc is the wavelength in free space, and ε ₁ is the dielectric constant of the dielectric member.

  As shown in FIG. 1, the slot antenna 23a to the slot antenna 23f are provided on the bottom surfaces of the waveguides 22a to 22f, respectively. Each slot antenna 23 is provided with thirteen slots 23a as through holes, as shown in FIG.

  The slots 23a of the slot antennas 23 are arranged at equal intervals of λg / 2, for example. In this way, 78 (= 13 × 6) slots 23 a are arranged on the ceiling of the chamber 10.

On the lower surface of the slot antenna 23, 39 dielectric parts 24 having a rectangular flat plate shape are arranged. Each dielectric part 24 is made of, for example, quartz glass, aluminum nitride (AlN), alumina (aluminum oxide: Al ₂ O ₃ ), sapphire, SiN, ceramics, or the like so as to transmit microwaves.

  As shown in FIG. 2, the beam 25 is formed in a lattice shape and supports 39 dielectric parts 24 on the lower surface of the slot antenna 23. The beam 25 is a conductor made of a metal that is a non-magnetic material such as aluminum, and is grounded via the slot antenna 23, the lid body 21, and the chamber 10 shown in FIG. 1. A plurality of gas introduction pipes 29 penetrate each beam 25, and the processing gas is injected from the injection hole 30 (see FIG. 2) at the tip of the gas introduction pipe 29.

1 includes a valve (valve 31a1, valve 31a3, valve 31b1, valve 31b3, valve 31b5, valve 31b7, valve 31c1, valve 31c3), mass flow controller (mass flow controller 31a2, mass flow controller 31b2, mass flow controller). 31b6, mass flow controller 31c2) and gas supply sources (O ₂ gas supply source 31a4, SiH ₄ and gas supply source 31b4, Ar gas supply source 31b8, CF ₄ gas supply source 31c4).

  The processing gas supply source 31 selectively supplies each processing gas into the chamber 10 by controlling opening and closing of each valve. Each mass flow controller adjusts the processing gas to a desired concentration by controlling the flow rate of the processing gas supplied by each mass flow controller.

For example, during the process, O ₂ gas is supplied from the O ₂ gas supply source 31a4 and injected into the processing chamber 10u through the gas flow path 32a. Further, SiH ₄ gas and Ar gas are respectively supplied from the SiH ₄ gas supply source 31b4 and the Ar gas supply source 31b8, and are injected into the processing chamber 10u through the gas flow path 32b.

Further, for example, during cleaning, O ₂ gas and CF ₄ gas are supplied from the O ₂ gas supply source 31a4 and the CF ₄ gas supply source 31c4, respectively, and are injected into the processing chamber 10u through the gas flow path 32a.

  A remote plasma 35 is installed outside the microwave plasma processing apparatus 100. The remote plasma 35 has a processing vessel 35a, a coil 35b, a high frequency power source 35c, a capacity C, and a transfer pipe 35d, and is used when the inside of the chamber 10 is cleaned.

  The processing container 35a is composed of a hollow tubular member and is formed of a dielectric. A coil 35b is spirally wound around the outer periphery of the processing container 35a. A high frequency power source 35c is connected to the coil 35b at one end, and the other end is grounded. A capacitor C for insulating the DC component is connected to the high frequency power supply 35c.

For example, CF ₄ gas, O ₂ gas, and Ar gas are supplied from the processing gas supply source 31 to the processing container 35 a as the cleaning gas. As another example of the cleaning gas, NF ₃ gas and Ar gas may be supplied. When the high frequency power output from the high frequency power supply 35c is applied to the coil 35b, a high frequency magnetic field is generated around the coil 35b. The cleaning gas is turned into plasma in the processing container 35a by the induced electric field induced by the temporal change of the magnetic field. The lifetime of radicals is long in the inductively coupled plasma (ICP) thus generated. As a result, only active F radicals are supplied to the processing chamber 10u through the transfer pipe 35d.

  A cooling water supply source 33 is disposed outside the microwave plasma processing apparatus 100. The cooling water supply source 33 cools the inside of the lid body 21 by circulating and supplying cooling water to a water channel 34 provided inside the lid body 21.

  Furthermore, a controller 40 is provided outside the microwave plasma processing apparatus 100. The controller 40 outputs drive signals to the electric motor 16a and the APC 19b at predetermined timings. The first pressure sensor 41 connected to the controller 40 is provided in the processing chamber 10u and detects the pressure P1 in the processing chamber 10u. Similarly, a second pressure sensor 42 connected to the controller 40 is provided in the exhaust chamber 10d and detects the pressure P2 in the exhaust chamber 10d.

  With such a configuration, the microwave output from the microwave generator 28 shown in FIG. 2 propagates through each waveguide 22, passes through each dielectric part 24 through each slot, and passes through each dielectric part 24. Is incident on the inside. In this way, the film forming gas supplied from the processing gas supply source 31 is turned into plasma by the electric field energy of the microwave incident into the processing chamber 10 u, and a gate oxide film is formed on the substrate G. When the reaction product deposited on the inner wall surface of the chamber reaches a predetermined thickness by performing the film forming process on the plurality of substrates G, the processing gas supply source 31 and the remote plasma 35 are connected to the F system. Gas is supplied as a cleaning gas, and the inner wall of the chamber is cleaned by the action of F radicals in the plasma generated from the cleaning gas. After cleaning, the film forming gas is supplied again from the processing gas supply source 31, and the same precoat film as the gate oxide film is formed on the inner wall of the chamber under the same process conditions as in the film formation. When the precoat film reaches a certain thickness, the substrate G is loaded again, and the film forming process is resumed.

(Raising and lowering of susceptor 11)
Next, the susceptor shown in FIG. 3 in each step of (1) film formation (gate oxide film formation), (2) cleaning, and (3) F-based gas reduction film formation (precoat film formation) described above. 11 will be described with reference to the results of actual experiments by the inventors.

The process conditions set by the inventors in each step during the experiment are as follows.
(1) Process conditions at the time of film formation (gate oxide film formation) The process conditions at this time are as follows: the pressure in the processing chamber 10u is 200 mTorr, the power of the microwave is 2.55 kW × 3 (three microwave generators 28 are used) )Met. Further, Ar gas, SiH ₄ gas, and O ₂ gas were used as gas types, and the gas amounts were Ar gas 1500 sccm, SiH ₄ gas 150 sccm, and O ₂ gas 950 sccm. The temperature of the substrate G was 300 ° C. The distance between the substrate G and the dielectric part 24 was 166 mm.

(2) Process conditions at the time of cleaning In the above description, CF ₄ gas, O ₂ gas, and Ar gas are given as examples of the cleaning gas, but NF ₃ gas and Ar gas were used as the F-based gas during the experiment. The gas amounts were 1000 sccm for Ar gas and 1000 sccm for NF ₃ gas. The pressure in the processing chamber 10u was 2 Torr, and the output from the high frequency power supply 35c was 10.8 kW. The distance between the substrate G and the dielectric part 24 was 194 mm.

  (3) The process conditions for forming the precoat film were the same as those for forming the film.

(1) Film Formation Before the process for forming the gate oxide film is started, the controller 40 transmits a drive signal for raising and lowering the susceptor 11 to a predetermined height defined in the process conditions to the electric motor 16a. . The susceptor 11 is raised to a predetermined height by the power output from the electric motor 16a in response to the drive signal (upper side in FIG. 3).

In this state, the controller 40 transmits a driving signal to the processing gas supply source 31 to supply the film forming gas, so that the processing gas supply source 31 supplies Ar gas, SiH ₄ gas, and O ₂ gas to the processing chamber. Supply in 10u. These film-forming gases are turned into plasma by microwaves.

  When the susceptor 11 is raised to a predetermined height, there is almost no gap between the susceptor 11 and the baffle plate 18. The APC 19b is controlled so as to open its valve body. Thereby, the processing chamber 10u can be maintained at a pressure (about 50 mTorr to about 500 mTorr) that matches the process conditions. As a result, the deposition radicals generated from the film forming gas are confined in the processing chamber 10u, so that the film forming speed is high and film formation with high uniformity can be performed on the substrate G.

(2) Cleaning When the reaction product deposited on the inner wall of the chamber reaches a predetermined thickness by repeating the process of forming gate oxide films on a large number of substrates G, the inside of the chamber is cleaned. At that time, the controller 40 transmits a drive signal for separating the susceptor 11 and the baffle plate 18 to the electric motor 16a. The susceptor 11 is lowered to a predetermined height by the power output from the electric motor 16a in response to the drive signal (lower side in FIG. 3). In this state, a predetermined interval (gap S) is generated between the susceptor 11 and the baffle plate 18. For this reason, the gas easily flows from the processing chamber 10u to the exhaust chamber 10d, and the difference between the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d becomes small.

  For example, during film formation, as shown by the line (A) in FIG. 4, when the pressure P1 in the processing chamber 10u is 500 mTorr, the pressure P2 in the exhaust chamber 10d is 250 mTorr, and the pressure P1 in the processing chamber 10u is It can be seen that the pressure is higher than the pressure P2 in the exhaust chamber 10d.

  On the other hand, at the time of cleaning, when the susceptor 11 is lowered so that the gap S becomes 1 cm, as shown by the line (B) in FIG. 4, when the pressure P1 in the processing chamber 10u is 500 mTorr, The pressure P2 is 480 mTorr, and it can be seen that the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d are very small.

In this state, the controller 40 transmits a drive signal to the processing gas supply source 31 to supply the cleaning gas, so that the processing gas supply source 31 supplies NF ₃ gas and Ar gas into the processing chamber 10u. . These cleaning gases are turned into plasma by microwaves.

Further, the processing gas supply source 31 supplies NF ₃ gas and Ar gas to the remote plasma 35 by the drive signal. The remote plasma 35 converts these cleaning gases into plasma and supplies F radicals into the exhaust chamber 10d. Specifically, the cleaning gas (NF ₃ , Ar) is supplied to the processing container 35a, and the high frequency power of the high frequency power source 35c is applied to the coil 35b. As a result, the gas is turned into a plasma by a high-frequency electric field derived from a high-frequency magnetic field generated around the coil 35b, and only the F radicals in the plasma are transmitted through the transport pipe 35d from the length of the lifetime to the end. Supplied into the chamber. The supplied F radicals attack the SiOx film attached to the inner wall of the chamber and are discharged out of the chamber as SiFx (SiF ₁ , SiF ₂ , SiF ₃ , SiF ₄ ) gas. Further, the remaining Ox reacts with N of the NF ₃ gas supplied to the processing chamber 10u to become a gas such as NO or NO ₂ and is discharged out of the chamber.

As described above, during cleaning, the susceptor 11 is positioned below, so that gas easily flows from the processing chamber 10u to the exhaust chamber 10d, and the difference between the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d is small. It has become. According to the above formula (1), the difference in cleaning speed between the chambers is eliminated by reducing the pressure difference between the chambers and making the F radicals in the processing chamber 10u substantially the same as the F radicals in the exhaust chamber 10d. Can do. As a result, the generation rates of gases such as SiFx gas, NO, and NO ₂ are substantially equal in the processing chamber 10u and the exhaust chamber 10d. As a result, the inner walls of the processing chamber 10u and the exhaust chamber 10d are more evenly cleaned and the cleaning time can be greatly shortened.

However, as described above, the plasma of the F-based gas is used for cleaning the microwave plasma processing apparatus 100, and the chamber body is made of Al and the ceiling is made of Al ₂ O ₃ . In such a situation, when F ions attack Al ₂ O ₃ , the bond between Al—O is broken and a film of Al—F or the like is partially generated. Further, the binding state of Al—F is 159 kcal / mol, and the binding state of Al—O is stable like Al ₂ O ₃ whose binding energy is 120 kcal / mol. As a result, during cleaning, Al in the chamber body and Al ₂ O _{3 in the} ceiling portion may be fluorinated, and the chamber inner wall and ceiling portion may partially become AlF.

Further, since the combined state of SiF ₄ and F ₂ generated at the time of cleaning is stable, some of them may not be discharged out of the chamber and physically adsorbed on the inner wall of the chamber. SiF ₄ and F ₂ adsorbed in this way are easily desorbed because of their low adsorption energy. Further, as described above, AlF partially fluorinated on the inner wall of the chamber becomes F when the Al—F bond is broken by ions during film formation, and is released into the chamber. In this way, there arises a problem that the F residue remaining in the chamber is desorbed and mixed into the thin film being formed.

  In addition to this, in order to increase the yield of the product during film formation and to manufacture the product stably, the supply of radicals into the chamber 10 before the film is formed, A series of circulations of forming a thin film and exhausting gas out of the chamber 10 needs to be in a steady state. That is, by setting the process conditions in the chamber to the same conditions as during film formation before film formation, it is necessary to perform stable film formation without radicals generated during the process being consumed on the inner wall of the chamber.

As described above, the problem that F desorption from Al-F and the like existing on the inner wall of the chamber and desorption of SiF ₄ and F ₂ from the inner wall of the chamber cause the deterioration of the film quality is solved. From the viewpoint of setting the process conditions to the same as those at the time of film formation before film formation, the same gas as that supplied at the time of film formation is converted to plasma after cleaning and before film formation (at the time of precoat film formation). Then, the surface of the inner wall of the chamber is coated with the plasma (that is, a so-called precoat film is formed). Next, the raising / lowering operation of the susceptor 11 during the formation of the precoat film will be described.

(3) Precoat film formation When the precoat film is formed, the inner wall surface of the chamber is coated with the same SiO ₂ film (gate oxide film) as in the process. At this time, a predetermined interval (gap S) remains between the susceptor 11 and the baffle plate 18. For this reason, in the chamber, the state where the gas easily flows from the processing chamber 10u to the exhaust chamber 10d is maintained, and the difference between the pressure P1 of the processing chamber 10u and the pressure P2 of the exhaust chamber 10d remains small. .

In this state, the controller 40 transmits a drive signal to the processing gas supply source 31 in order to supply a gas for forming the precoat film, so that the processing gas supply source 31 again uses the same gas as the film forming gas. Ar gas, SiH ₄ gas, and O ₂ gas are supplied into the processing chamber 10u. These film-forming gases are turned into plasma by microwaves.

  As described above, according to the above formula (1), the pressure difference between the chambers is reduced, and the deposition radicals in the processing chamber 10u are made substantially the same as the deposition radicals in the exhaust chamber 10d. The difference can be eliminated. As a result, the film thicknesses of the precoat films in the processing chamber 10u and the exhaust chamber 10d can be made equal and the film quality can be uniformly formed, and the time for forming the precoat film to a predetermined thickness is greatly reduced. can do.

  Thus, in the present embodiment, the gap S is provided between the susceptor 11 and the baffle plate 18 during cleaning and precoat film formation. As a result, the inner wall of the chamber can be cleaned more evenly, the film thickness of the precoat film can be made equal, and the film quality can be formed uniformly. As a result, the cleaning time and the precoat film forming time can be greatly shortened, the throughput can be improved, and the productivity can be increased.

  Further, at the time of film formation, the baffle plate 18 is raised so that there is almost no gap between the baffle plate 18 and the susceptor 11. As a result, since the distribution of the deposit radicals in the processing chamber 10u can be made uniform, a high-quality gate oxide film can be formed on the substrate G.

(Modification 1 of the first embodiment)
Next, the configuration and operation of the microwave plasma processing apparatus 100 according to Modification 1 of the first embodiment will be described with reference to FIG. In this apparatus, a support for supporting the baffle plate 18 is also disposed on the side wall portion of the susceptor 11, and the baffle plate 18 is detachably fixed to either the inner wall side portion of the chamber 10 or the side wall portion of the susceptor. This is different from the microwave plasma processing apparatus of the first embodiment in which the baffle plate 18 is fixed to the inner wall side portion of the chamber 10. Therefore, this difference will be mainly described.

  On the inner wall side portion of the chamber 10, a receiving tool 18a that protrudes toward the susceptor 11 at a substantially central position is attached. In addition, a support 18 b that protrudes toward the side wall of the chamber 10 is also attached to substantially the center of the side surface of the susceptor 11. The baffle plate 18 is detachably fixed to either the chamber 10 or the susceptor 11 depending on the height of the susceptor 11.

Next, the raising / lowering operation of the susceptor 11 in the case of this modification will be described.
(1) Film Formation During film formation, the controller 40 transmits a drive signal to the electric motor 16a, and the susceptor 11 is raised to a predetermined height by the operation of the electric motor 16a according to the drive signal. While rising, the baffle plate 18 is fixed to the side wall of the susceptor 11 by being supported by the receiving member 18b at the inner peripheral edge of the lower surface, and rises to a predetermined height together with the susceptor 11 (upper side in FIG. 5).

In this state, there is almost no gap between the susceptor 11 and the baffle plate 18. Therefore, the pressure P1 in the processing chamber 10u is maintained in a state that matches the process conditions. As a result, since the deposition radical is confined in the processing chamber, a highly uniform SiO ₂ film is formed on the substrate G at a high deposition rate.

(2) Cleaning When the reaction product deposited on the inner wall of the chamber reaches a predetermined thickness, the controller 40 transmits a drive signal to the electric motor 16a, and the electric motor 16a operates in accordance with this drive signal, whereby the susceptor 11 Descends to a predetermined height (bottom of FIG. 5). When the baffle plate 18 fixed to the susceptor 11 is lowered to the height at which the receiving device 18a on the chamber 10 side is provided while descending, the baffle plate 18 is engaged with the receiving device 18a at the outer peripheral edge of the lower surface. Match. Thereafter, when the susceptor 11 is further lowered, the baffle plate 18 leaves the support 18b on the susceptor 11 side, is fixed to the support 18a on the inner wall side portion of the chamber 10, and only the susceptor 11 is lowered to a predetermined height.

In this state, when the cleaning gas is supplied, a predetermined interval (gap S) is generated between the susceptor 11 and the baffle plate 18, so that the pressure P1 in the processing chamber 10 u and the pressure P2 in the exhaust chamber 10 d are reduced. The difference is reduced, and the difference in cleaning speed between the chambers can be eliminated by making the deposition radicals in the processing chamber 10u substantially the same as the deposition radicals in the exhaust chamber 10d. As a result, the generation rates of gases such as SiFx gas, NO, and NO ₂ are substantially equal in the processing chamber 10u and the exhaust chamber 10d. As a result, as in the case of the first embodiment, the inner walls of the processing chamber 10u and the exhaust chamber 10d are more evenly cleaned, and the cleaning time can be greatly shortened.

(3) Precoat film formation Since the height of the susceptor 11 remains unchanged when the precoat film is formed, the difference between the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d remains small. In this state, as in the case of the first embodiment, when the gas for forming the precoat film is supplied, the generated deposit radicals are substantially the same in the processing chamber 10u and the exhaust chamber 10d, and the film formation in each chamber is performed. Almost no difference in speed. As a result, the film thicknesses of the precoat films in the processing chamber 10u and the exhaust chamber 10d can be made equal and the film quality can be uniformly formed, and the time for forming the precoat film to a predetermined thickness is greatly reduced. can do.

  As described above, in this modification, the baffle plate 18 is fixed to the chamber wall surface side during cleaning and precoat film formation. In this way, by providing the gap S between the susceptor 11 and the baffle plate 18 and making the state of the deposition radicals substantially the same, the inner wall of the chamber can be more evenly cleaned and the film thickness of the precoat film can be reduced. More uniform and uniform film quality can be formed. As a result, the cleaning time and the precoat film formation time can be greatly shortened. As a result, throughput can be improved and productivity can be increased.

On the other hand, in this modification, the baffle plate 18 is fixed to the susceptor 11 side during film formation. Thereby, the baffle plate 18 can be raised together with the susceptor 11. The positional relationship between the stage on which the substrate G is placed and the baffle plate 18 greatly affects the quality of the SiO ₂ film. Therefore, a high-quality gate oxide film can be formed on the substrate G by moving the baffle plate 18 to the optimum position together with the susceptor 11 as in this modification.

(Modification 2 of the first embodiment)
Next, the configuration and operation of the microwave plasma processing apparatus 100 according to the second modification of the first embodiment will be described with reference to FIG. The baffle plate 18 according to this modification is provided with one or more through-holes and an opening / closing mechanism for opening / closing the through-holes. This is different from the microwave plasma processing apparatus 100 of the first embodiment that adjusts the gap S between the susceptor 11 and the baffle plate 18 by raising and lowering 11. Therefore, this difference will be mainly described.

  As shown in FIG. 7, which is an enlarged view of the portion indicated by XP in FIG. 6, the baffle plate 18 includes a baffle plate body 18c having one or more through holes (only the through hole 18c1 is shown in the drawing). An opening / closing mechanism 18d for opening / closing the through hole 18c1 is provided.

  The baffle plate main body 18c is fixed to the approximate center of the side wall of the susceptor 11 at the inner peripheral edge of the lower surface thereof by being supported by a receiver 18b attached to the approximate center of the side surface of the susceptor 11. The opening / closing mechanism 18d has the same shape as the baffle plate main body 18c, has a through hole of the same shape at the same position as the through hole of the baffle plate main body 18c, and is provided in close contact with the upper surface of the baffle plate main body 18c. ing. The opening / closing mechanism 18d is threaded into the power transmission member 50 at the outer peripheral side wall thereof. The power transmission member 50 passes through the side wall of the chamber 10 and is connected to the electric motor 51. A boundary between the outer wall of the chamber 10 and the power transmission member 50 is sealed by an O-ring 52, thereby maintaining airtightness in the chamber 10.

  The power of the electric motor 51 is transmitted to the opening / closing mechanism 18d through the power transmission member 50, whereby the opening / closing mechanism 18d slides in the left-right direction. When the opening / closing mechanism 18d slides in this manner, the positions of the through hole 18c1 of the baffle plate body 18c and the through hole 18d1 of the opening / closing mechanism 18d are shifted. In this way, the opening ratio between the susceptor 11 and the side wall of the chamber 10 is controlled by adjusting the gap (opening area S between the through hole 18c1 and the through hole 18d1).

Next, the lifting / lowering operation of the susceptor 11 according to this modification will be described with reference to FIG.
(1) Film formation During film formation, the controller 40 transmits a drive signal to the electric motor 16a. In the electric motor 16a, the opening / closing mechanism 18d slides by a predetermined amount by the power output from the electric motor 16a in response to this drive signal (upper side in FIG. 6). Thereby, the opening area S of the through-hole 18c1 and the through-hole 18d1 which penetrates the baffle board 18 becomes small. As a result, the pressure P1 in the processing chamber 10u is maintained at a value that matches the process conditions. As a result, since the deposition radical is confined in the processing chamber, the film formation speed on the substrate G is high, and film formation with high uniformity can be performed.

(2) Cleaning When the reaction product deposited on the inner wall of the chamber reaches a predetermined thickness, the controller 40 transmits a drive signal to the electric motor 16a. The electric motor 16a slides in a direction opposite to that during film formation by a predetermined amount by the power output from the electric motor 16a in response to this drive signal (lower side in FIG. 6). Thereby, the opening area S of the through-hole 18c1 and the through-hole 18d1 which penetrates the baffle board 18 becomes large. Thus, by increasing the aperture ratio between the susceptor 11 and the baffle plate 18 during cleaning, the difference between the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d can be reduced. In this state, cleaning gas is supplied into the chamber, and the inner wall of the chamber is cleaned. As a result, the inner walls of the processing chamber 10u and the exhaust chamber 10d are more evenly cleaned and the cleaning time can be greatly shortened.

(3) Precoat film formation During the formation of the precoat film, the film forming gas is supplied with the position of the opening / closing mechanism 18d as it is. Thereby, the state of the deposit radical can be made substantially the same in the processing chamber 10u and the exhaust chamber 10d. As a result, the film thicknesses of the precoat films in the processing chamber 10u and the exhaust chamber 10d can be made more equal and the film quality can be uniformly formed. As a result, the time for forming the precoat film to a predetermined thickness can be greatly shortened.

  As described above, in this modification, the opening / closing mechanism 18d of the baffle plate 18 is controlled so that the aperture ratio during cleaning and precoat film formation is 1 or 2 so that the aperture ratio during film formation is larger than that during film formation. The opening degree of the above through holes is adjusted. As a result, the difference between the pressure P1 in the processing chamber 10u and the pressure P2 in the exhaust chamber 10d can be reduced. As a result, it is possible to eliminate the difference in the deposition rate between the chambers by making the state of the deposit radicals substantially the same in the processing chamber 10u and the exhaust chamber 10d. Thereby, the film thicknesses of the precoat films in the processing chamber 10u and the exhaust chamber 10d can be made equal and the film quality can be uniformly formed. On the other hand, at the time of film formation, by reducing the opening area S of the through hole 18c1 and the through hole 18d1 penetrating the baffle plate 18, the deposition rate is confined in the processing chamber, so that the film formation speed is high and uniform. A film can be applied to the substrate G.

(Second Embodiment)
Next, the configuration and operation of the microwave plasma processing apparatus 100 according to the second embodiment will be described with reference to FIG. In this apparatus, in addition to a processing gas supply source 31 for supplying a film forming processing gas and a remote plasma 35 for supplying a cleaning gas (both omitted in FIG. 8, refer to FIG. 1), a precoat film is formed on the exhaust chamber 10d side. It differs from the microwave plasma processing apparatus of the first embodiment that does not have the remote plasma 60 on the exhaust chamber 10d side in that it has the remote plasma 60 that supplies the gas for use. Further, the present embodiment is different from the first embodiment in which the susceptor 11 does not move up and down in that the susceptor 11 does not move up and down. Therefore, this difference will be mainly described.

  The remote plasma 60 provided outside the microwave plasma processing apparatus 100 has a processing vessel 60a, a coil 60b, a high frequency power source 60c, a capacity C, and a transfer pipe 60d, and forms a precoat film in the chamber 10. Used for.

The processing vessel 60a is supplied with a processing gas from the gas supply source as a gas for forming a precoat film, which is the same as the processing gas used for plasma processing of the substrate G (here, SiH ₄ gas, O ₂ gas, Ar gas). Supplied from source 31. When the high frequency power output from the high frequency power supply 60c is applied to the coil 60b, a high frequency magnetic field is generated around the coil 60b. The gas is turned into plasma in the processing chamber 60a by the induced electric field induced by the temporal change of the magnetic field. The lifetime of radicals in the inductively coupled plasma generated in this way is long. As a result, only active deposit radicals are supplied to the exhaust chamber 10d through the transfer pipe 60d.

Next, the operation of the remote plasma 60 according to the present embodiment will be described with reference to FIG.
(1) During film formation and cleaning At the time of film formation and cleaning, the controller 40 does not transmit a drive signal to the remote plasma 60. Therefore, the remote plasma 60 does not operate during film formation and cleaning (upper part of FIG. 8). Therefore, at the time of film formation, the film formation gas is supplied from the processing gas supply source 31 shown in FIG. At the time of cleaning, a cleaning gas is supplied from the processing gas supply source 31 and the remote plasma 35 to the processing chamber 10u, and the inside of the chamber 10 is cleaned.

(2) At the time of precoat film formation When the precoat film is formed, SiH ₄ gas, O ₂ gas, and Ar gas are supplied to the process chamber 10 u from the process gas supply source 31. The supplied gas is turned into plasma by the electric field energy of the microwave transmitted through the dielectric part 24, thereby forming a gate oxide film as a precoat film inside the chamber 10.

  Normally, since the gas supplied to the processing chamber 10u is preferentially used for film formation in the processing chamber 10u, the residual amount of gas (depot radical) flowing into the exhaust chamber 10d is reduced. Further, there is almost no gap S between the baffle plate 18 and the susceptor 11. As a result, the pressure difference between the processing chamber 10u and the exhaust chamber 10d partitioned by the baffle plate 18 is increased, and depot radicals are confined in the processing chamber 10u, so that very few depot radicals flow into the exhaust chamber 10d from the processing chamber 10u. Become. As a result, the precoat film in the exhaust chamber 10d is very thin compared to the precoat film in the processing chamber 10u.

  However, in this embodiment, the remote plasma 60 supplies the deposit radical to the exhaust chamber 10d. Specifically, first, the controller 40 transmits a drive signal to the high frequency power supply 60c. The high frequency power supply 60c supplies high frequency power to the coil 60b in accordance with this drive signal (bottom in FIG. 8).

When the high frequency power is applied to the coil 60b, a high frequency magnetic field is generated around the coil 60b, and the gas in the processing container 60a is turned into plasma by the energy of the high frequency electric field induced by this magnetic field. The lifetime of radicals in the inductively coupled plasma generated in this way is long. As a result, only active deposit radicals are supplied to the exhaust chamber 10d through the transfer pipe 60d.

  According to this, even if the residual amount of deposit radicals flowing from the processing chamber 10u to the exhaust chamber 10d is small, the formation of the precoat film on the inner wall surface of the exhaust chamber 10d is promoted by the deposit radicals supplied from the remote plasma 60. As a result, even if the susceptor 11 is not moved up and down, the precoat film in the processing chamber 10u and the precoat film in the exhaust chamber 10d can be made more uniform and the film quality can be uniformly formed.

  As described above, according to each embodiment, a precoat film having a uniform film quality and a substantially equal film thickness can be formed in a shorter time by the inner wall of the processing chamber 10u and the inner wall of the exhaust chamber 10d. . As a result, the time required for the thickness of the deposit deposited on the inner wall of the chamber during the process to reach the thickness of film peeling increases, so that the cycle for cleaning the inside of the chamber can be lengthened. As a result, throughput can be improved and productivity can be increased.

  In each embodiment, the aperture ratio between the susceptor 11 and the inner wall of the chamber 10 is preferably 1.4%.

  In the first embodiment and the first modification of the first embodiment, the drive signal for lowering the susceptor 11 to a predetermined position is output during cleaning. However, the controller 40 may output a drive signal when forming the precoat film instead of during cleaning. According to this, the susceptor 11 is lowered to a predetermined position when the precoat film is formed.

  Similarly, in Modification 2 of the first embodiment, a drive signal for sliding the opening / closing mechanism 18d to a predetermined position is output during cleaning. However, the controller 40 may output a drive signal when the precoat film is formed. According to this, the aperture ratio is controlled to be large when the precoat film is formed.

In each of the above embodiments, as the cleaning gas, not only F-based cleaning gases such as NF ₃ , SF ₆ , and CF _4, but also chlorine-based cleaning gases such as Cl and Cl ₂ may be used.

  In each of the above embodiments, a method of generating plasma by remote plasma is used for generation of F radicals at the time of cleaning and generation of deposit radicals at the time of forming the precoat film. However, the method of generating each radical is not limited to this, and can be generated by supplying energy such as heat, light, and radiation.

  Further, at the time of cleaning, the processing gas supply source 31 and the remote plasma 35 may be used in combination, or only the remote plasma 35 may be used, or only the processing gas supply source 31 may be used.

  In the above embodiment, the operations of the respective units are related to each other, and can be replaced as a series of operations in consideration of the relationship between each other. And by replacing in this way, the embodiment of the microwave plasma processing apparatus 100 can be made an embodiment of a method for controlling the microwave plasma processing apparatus 100.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, the plasma processing apparatus according to the present invention is not limited to the microwave plasma processing apparatus, and may be an inductively coupled plasma processing apparatus or a capacitively coupled plasma processing apparatus.

  Further, the plasma processing apparatus according to the present invention may be a microwave plasma processing apparatus having a plurality of tile-shaped dielectrics, and a microwave plasma processing apparatus having a large-area dielectric that is not divided into tiles. It may be.

  Further, the plasma processing apparatus according to the present invention is not limited to the CVD process, and can perform any process that can be performed by the generated plasma, such as an ashing process or an etching process.

  The present invention is applicable to a plasma processing apparatus that coats the inner wall of a chamber to a more uniform thickness and a method for controlling the plasma processing apparatus.

It is a longitudinal cross-sectional view of the microwave plasma processing apparatus concerning one Embodiment. It is the figure which showed the chamber ceiling part concerning one Embodiment. It is a figure for demonstrating the relationship between each process in 1st Embodiment, and the position of a susceptor. It is the graph which showed the relationship between the pressure P1 of a process chamber, and the pressure P2 of an exhaust chamber according to the clearance gap between a susceptor and a baffle board. The figure for demonstrating the relationship between the position of a susceptor and each process in the modification 1 of 1st Embodiment about the relationship between the waveguide for electric power feeding and the thickness of the dielectric material required in order to shift the phase of a microwave by a half cycle It is. It is a figure for demonstrating the relationship between each process and the position of a susceptor in the modification 2 of 1st Embodiment. It is an enlarged view of the baffle board vicinity in the modification 2 of 1st Embodiment. It is a figure for demonstrating the relationship between each process in 2nd Embodiment, and the position of a susceptor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Chamber 11 Susceptor 18 Baffle plate 18a, 18b Receiver 31 Processing gas supply source 35, 60 Remote plasma 40 Controller 100 Microwave plasma processing apparatus 10u Processing chamber 10d Exhaust chamber

Claims (12)

A plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas,
A control device for controlling the mounting table is provided,
When the precoat film is formed on the inner wall surface of the chamber, the control device changes the position of the mounting table with respect to the baffle plate so that the pressure of the processing chamber and the pressure of the exhaust chamber approach each other. A plasma processing apparatus for changing an aperture ratio between a mounting table and the chamber side wall. Equipped with an elevating mechanism for elevating the mounting table,
The baffle plate is fixed to the inner wall of the chamber;
The mounting table is moved up and down by the control device so that the aperture ratio when the precoat film is formed on the inner wall surface of the chamber is larger than the aperture ratio when the object to be processed is plasma-treated. The plasma processing apparatus according to claim 1, wherein a distance between the baffle plate and the baffle plate is adjusted. Equipped with an elevating mechanism for elevating the mounting table,
The baffle plate is detachably fixed to either the chamber or the mounting table.
When plasma processing is performed on an object to be processed, the control device fixes the baffle plate to the mounting table while raising or lowering the mounting table, and the control device forms a precoat film on the inner wall surface of the chamber. By fixing the baffle plate to the chamber while raising and lowering the mounting table in the above, the aperture ratio when forming the precoat film on the inner wall surface of the chamber is the aperture ratio when plasma processing is performed on the object to be processed The plasma processing apparatus according to claim 1, wherein an interval between the mounting table and the baffle plate is adjusted to be larger. A plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas,
The baffle plate has one or more through holes and an opening / closing mechanism for adjusting the opening degree of the through holes,
A control device for controlling the opening and closing mechanism;
By controlling the opening / closing mechanism of the baffle plate with the control device so that the pressure of the processing chamber and the pressure of the exhaust chamber approach when forming a precoat film on the inner wall surface of the chamber, the inner wall of the chamber A plasma processing apparatus for adjusting an opening degree of the one or more through holes so that an opening ratio of the through holes when forming the precoat film on the surface is larger than the opening ratio when the object to be processed is plasma processed . A plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas,
Provided outside the chamber is a radical generator that generates radicals that promote the formation of a precoat film on the inner wall surface of the chamber;
A transport pipe connecting the exhaust chamber and the radical generator is provided;
A plasma processing apparatus comprising: a control device that controls the radical to be supplied to the exhaust chamber through the transfer pipe after the chamber is cleaned. The radical generator is remote plasma,
The remote plasma includes a processing vessel formed of a dielectric material,
The plasma processing apparatus according to claim 5, wherein the radical is generated by converting the gas supplied to the processing container into plasma by the control device. By the control device, according to claim 6, wherein the radicals are controlled to be generated by supplying the same gas and gas supplied when performing a plasma process on a target object in the remote plasma Plasma processing equipment. In the microwave plasma processing apparatus, the control device controls the processing target to be plasma-treated by converting the processing gas supplied into the chamber into plasma by microwaves passing through the slot and passing through the dielectric. The plasma processing apparatus according to any one of claims 1 to 7. The dielectric is composed of a plurality of dielectric parts,
Each dielectric part is provided with one or more slots,
Wherein the controller, the one or more processing gas supplied into the chamber by the microwave slot through to the respective dielectric parts were transmitted respectively by plasma, to perform a plasma process on a target object The plasma processing apparatus according to claim 8 to be controlled . A control method of a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas,
When plasma processing the object to be processed, the mounting table is moved up and down to the first position,
When the chamber is cleaned and when the precoat film is formed on the inner wall surface of the chamber, the distance between the mounting table when forming the precoat film and the baffle plate, and the mounting table when plasma processing is performed on the workpiece A control method for a plasma processing apparatus, wherein the mounting table is moved up and down to a second position to be larger than a distance from the baffle plate. A chamber partitioned by a baffle plate having one or two or more through-holes and an opening / closing mechanism for opening and closing the through-holes and a mounting table into a processing chamber for performing plasma processing on the object to be processed and an exhaust chamber for exhausting gas A method of controlling a plasma processing apparatus comprising:
When the object to be processed is plasma-treated, the opening / closing mechanism is slid to the first position,
When the chamber is cleaned and when the precoat film is formed on the inner wall surface of the chamber, the opening degree of the through hole when forming the precoat film is larger than the opening degree of the through hole when the object to be processed is plasma-treated. A control method of a plasma processing apparatus for sliding the opening / closing mechanism to a second position for the purpose. A control method of a plasma processing apparatus having a chamber partitioned by a mounting table and a baffle plate into a processing chamber for performing plasma processing on an object to be processed and an exhaust chamber for exhausting gas,
A method for controlling a plasma processing apparatus, wherein after the chamber is cleaned, radicals that promote the formation of a precoat film on the inner wall surface of the chamber are supplied to the exhaust chamber.

Images