JP2013033979A - Microwave plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microwave plasma processing apparatus which controls ion distribution thereby realizing plasma processing achieving high in-plane uniformity with microplasma containing ions.SOLUTION: In a microwave plasma processing apparatus, a placement stand 2, on which a workpiece W is placed, is provided in a chamber 1 where a top wall is formed by a microwave transmission plate 28 made of a dielectric substance. Plasma is formed by the microwaves penetrating through the microwave transmission plate 28 and plasma processing is performed on the workpiece W, placed on the placement stand 2, with the plasma. In the microwave plasma processing apparatus, the microwave transmission plate 28 is provided so as to face the placement stand 2 and has an irregular shape part 42 at a portion on a microwave transmission surface which corresponds to at least a region reaching an edge of the workpiece W in a peripheral part of the workpiece W placed on the placement stand 2. A portion of the microwave transmission surface, which corresponds to a center part of the workpiece W, serves as a flat part 43.

Description

  The present invention relates to a microwave plasma processing apparatus.

  Plasma processing is an indispensable technology for the manufacture of semiconductor devices. Recently, the design rules of semiconductor elements constituting LSIs have been increasingly miniaturized due to the demand for higher integration and higher speed of LSIs, and semiconductor wafers Along with this, there is a demand for plasma processing apparatuses that can cope with such miniaturization and enlargement.

  However, in parallel plate type and inductively coupled plasma processing apparatuses that have been widely used in the past, the electron temperature is high, resulting in plasma damage to fine elements, and because the region where the plasma density is high is limited, it is large. It is difficult to uniformly and rapidly plasma-treat the semiconductor wafer.

  Therefore, an RLSA (Radial Line Slot Antenna) microwave plasma processing apparatus that can uniformly form a plasma with a high density and a low electron temperature has attracted attention (for example, Patent Document 1).

  The RLSA microwave plasma processing apparatus is provided with a planar antenna (Radial Line Slot Antenna) in which a number of slots are formed in a predetermined pattern at the upper part of a chamber, and the microwave guided from the microwave generation source is transmitted to the slot of the planar antenna And is radiated into a chamber held in a vacuum through a microwave transmission plate made of a dielectric material provided below, and the gas introduced into the chamber is converted into plasma by this microwave electric field. An object to be processed such as a semiconductor wafer is processed by the plasma thus formed.

  In this RLSA microwave plasma processing apparatus, a high plasma density can be realized over a wide region directly under the antenna, and uniform plasma processing can be performed in a short time. Further, since the low electron temperature plasma is formed, damage to the element is small.

  Taking advantage of such low damage and high uniformity, application to oxidation treatment is attracting attention. When a silicon substrate is directly oxidized such as formation of a gate oxide film, Si-Si bond energy is obtained. Is about 2.3 eV, so that an oxidation treatment with relatively high in-plane uniformity is realized in a relatively high pressure region where radicals are dominant.

  On the other hand, in recent years, a three-layer structure (ONO structure) in which a nitride film is formed on an oxide film and an oxide film is further formed thereon as an insulating film between a floating gate and a control gate of a nonvolatile memory element. In many cases, it has been attempted to perform RLSA microwave plasma treatment on the final oxide film on the silicon nitride (SiN) film. In that case, since the binding energy of SiN is 3.5 eV, Not only radicals but also ions with higher energy are required.

International Publication No. 2004/008519 Pamphlet JP 2006-40638 A

  However, when the plasma is formed under the condition that there are relatively many ions in the plasma, the ion distribution control cannot be performed sufficiently, and the oxide film formed on the SiN film has a convex non-uniformity. It becomes distribution.

  The present invention has been made in view of such circumstances, and provides a microwave plasma processing apparatus capable of realizing plasma processing with high in-plane uniformity by using microwave plasma containing ions by controlling ion distribution. For the purpose.

  In order to solve the above-described problems, the present invention provides a mounting table for mounting an object to be processed in a chamber made of a dielectric material and having a top wall formed of a microwave transmitting plate whose lower surface is a microwave transmitting surface. A microwave plasma processing apparatus is provided that forms plasma by microwaves transmitted through the microwave transmission plate and applies plasma processing to the object to be processed placed on the mounting table by the plasma. The plate is provided opposite to the mounting table, and at least a portion of the microwave transmitting surface corresponding to a region corresponding to a region up to the edge of the processing object at a peripheral portion of the processing object placed on the mounting table. There is provided a microwave plasma processing apparatus having a shape portion, and a portion corresponding to a central portion of an object to be processed is a flat portion.

  In the above configuration, the uneven portion can suppress the standing wave in the radial direction in the microwave transmission plate and increase the ion density of the portion corresponding to the peripheral portion of the object to be processed.

  According to the present invention, the microwave transmitting plate is provided with a concavo-convex portion at a portion corresponding to a region up to the edge of the object to be processed in at least a peripheral part of the object to be processed mounted on the mounting table of the microwave transmitting surface. Since the portion corresponding to the central portion of the object to be processed is a flat portion, the uneven portion of the peripheral portion suppresses the standing wave in the radial direction and the portion corresponding to the peripheral portion of the target object By increasing the ion density, an ion distribution with high in-plane uniformity can be obtained, and plasma processing with high in-plane uniformity can be realized by microwave plasma containing ions.

1 is a schematic cross-sectional view showing a microwave plasma processing apparatus according to an embodiment of the present invention. The drawing which shows the structure of the planar antenna member of the microwave plasma processing apparatus of FIG. The side view and bottom view which show the structure of the microwave permeation | transmission board of the microwave plasma processing apparatus of FIG. The figure for demonstrating the preferable range between the flat part diameter and wafer diameter of the microwave permeation | transmission board of the microwave plasma processing apparatus of FIG. Sectional drawing for demonstrating the application example of the apparatus of this invention. The figure for demonstrating the ion density distribution in a comparison apparatus and this invention apparatus.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view schematically showing a microwave plasma processing apparatus according to an embodiment of the present invention. This plasma processing apparatus introduces microwaves into a processing chamber using a planar antenna having a plurality of slots, particularly an RLSA (Radial Line Slot Antenna) to generate plasma, thereby achieving high density and low electron density. The apparatus is configured as an RLSA microwave plasma processing apparatus capable of generating microwave plasma at a temperature, and is suitably used for, for example, a plasma oxidation process. In this embodiment, an example applied to an oxidation process of a nitride film will be described.

  The plasma processing apparatus 100 has a substantially cylindrical chamber 1 that is airtight and grounded. A circular opening 10 is formed at a substantially central portion of the bottom wall 1a of the chamber 1, and an exhaust chamber 11 that communicates with the opening 10 and protrudes downward is provided on the bottom wall 1a. .

  A susceptor 2 made of ceramics such as AlN for horizontally supporting a semiconductor wafer (hereinafter referred to as “wafer”) W, which is a substrate to be processed, is provided in the chamber 1. The susceptor 2 is supported by a support member 3 made of ceramic such as cylindrical AlN that extends upward from the center of the bottom of the exhaust chamber 11. A guide ring 4 for guiding the wafer W is provided on the outer edge of the susceptor 2. A resistance heating type heater 5 is embedded in the susceptor 2. The heater 5 is supplied with power from a heater power source 6 to heat the susceptor 2 and heats the wafer W as a processing object. To do. At this time, for example, the processing temperature can be controlled in a range from room temperature to 800 ° C. A cylindrical liner 7 made of quartz is provided on the inner periphery of the chamber 1. This liner 7 can prevent contamination such as metal and form a clean environment. In addition, a quartz baffle plate 8 having a large number of exhaust holes 8 a is provided in an annular shape on the outer peripheral side of the susceptor 2 to uniformly exhaust the inside of the chamber 1, and this baffle plate 8 is supported by a plurality of support columns 9. Has been.

  The susceptor 2 is provided with wafer support pins (not shown) for supporting the wafer W and moving it up and down so as to protrude and retract with respect to the surface of the susceptor 2.

An annular gas introduction member 15 is provided on the side wall of the chamber 1, and gas emission holes are evenly formed. A gas supply system 16 is connected to the gas introduction member 15. The gas introduction member may be arranged in a shower shape. The gas supply system 16 includes, for example, an Ar gas supply source 17, an O ₂ gas supply source 18, and an H ₂ gas supply source 19, and these gases are respectively supplied to the gas introduction member 15 via the gas line 20. Thus, the gas is introduced uniformly from the gas radiation hole of the gas introduction member 15 into the chamber 1. Each of the gas lines 20 is provided with a mass flow controller 21 and front and rear opening / closing valves 22. Note that other rare gases such as Kr, He, Ne, and Xe may be used in place of the Ar gas, and no rare gas may be included as will be described later.

  An exhaust pipe 23 is connected to the side surface of the exhaust chamber 11, and an exhaust device 24 including a high-speed vacuum pump is connected to the exhaust pipe 23. Then, by operating the exhaust device 24, the gas in the chamber 1 is uniformly discharged into the space 11 a of the exhaust chamber 11 and exhausted through the exhaust pipe 23. Thereby, the inside of the chamber 1 can be depressurized at a high speed to a predetermined degree of vacuum, for example, 0.133 Pa.

  On the side wall of the chamber 1, there are a loading / unloading port 25 for loading / unloading the wafer W to / from a transfer chamber (not shown) adjacent to the plasma processing apparatus 100, and a gate valve 26 for opening / closing the loading / unloading port 25. Is provided.

The upper portion of the chamber 1 is an opening, and a ring-shaped support portion 27 is provided along the peripheral edge of the opening. A microwave transmitting plate 28 made of a dielectric material such as quartz or Al ₂ O ₃ and transmitting microwaves is airtightly provided on the support portion 27 via a seal member 29. Therefore, the inside of the chamber 1 is kept airtight. The microwave transmitting plate 28 has an uneven portion 42 in which unevenness is formed on the lower surface thereof, that is, the peripheral portion of the wafer W (wafer W on the susceptor 2) on the microwave transmitting surface. A portion corresponding to the portion is a flat portion 43. Details of the microwave transmission plate 28 will be described later.

  A disk-shaped planar antenna member 31 is provided above the microwave transmission plate 28 so as to face the susceptor 2. The planar antenna member 31 is locked to the upper end of the side wall of the chamber 1. The planar antenna member 31 is a disk made of a conductive material having a diameter of 300 to 400 mm and a thickness of 0.1 to several mm (for example, 1 mm), for example, when it corresponds to an 8-inch wafer W. Specifically, for example, the surface is made of a copper plate or aluminum plate plated with silver or gold, and a large number of microwave radiation holes 32 (slots) are formed in pairs to penetrate in a predetermined pattern. . As shown in FIG. 2, for example, the microwave radiation holes 32 form a pair, and the pair of microwave radiation holes 32 are typically arranged in a “T” shape. A plurality of pairs are arranged concentrically. The length and arrangement interval of the microwave radiation holes 32 are determined in accordance with the wavelength (λg) of the microwave. For example, the distance between the microwave radiation holes 32 is λg / 4, λg / 2, or λg. The In FIG. 2, the interval between adjacent microwave radiation holes 32 formed concentrically is indicated by Δr.

  Further, the microwave radiation hole 32 may have another shape such as a circular shape or an arc shape. Furthermore, the arrangement | positioning form of the microwave radiation hole 32 is not specifically limited, For example, it can also arrange | position in spiral shape and radial form other than concentric form.

  On the upper surface of the planar antenna member 31, a slow wave material 33 made of a resin such as quartz, polytetrafluoroethylene, or polyimide having a dielectric constant larger than that of a vacuum is provided. The slow wave material 33 has a function of adjusting the plasma by shortening the wavelength of the microwave because the wavelength of the microwave becomes longer in vacuum. The planar antenna member 31 and the microwave transmission plate 28 and the slow wave member 33 and the planar antenna member 31 are arranged in close contact with each other, but may be arranged apart from each other. Good.

  A shield lid 34 made of a metal material such as aluminum, stainless steel, or copper is provided on the upper surface of the chamber 1 so as to cover the planar antenna member 31 and the slow wave material 33. The upper surface of the chamber 1 and the shield lid 34 are sealed by a seal member 35. A cooling water flow path 34 a is formed in the shield lid 34, and the cooling lid 34, the slow wave material 33, the planar antenna member 31, and the microwave transmission plate 28 are cooled by flowing cooling water therethrough. It is supposed to be. The shield lid 34 is grounded.

  An opening 36 is formed at the center of the upper wall of the shield lid 34, and a waveguide 37 is connected to the opening. A microwave generator 39 is connected to the end of the waveguide 37 via a matching circuit 38. Thereby, for example, a microwave having a frequency of 2.45 GHz generated by the microwave generator 39 is propagated to the planar antenna member 31 through the waveguide 37. Note that the microwave frequency may be 8.35 GHz, 1.98 GHz, or the like.

  The waveguide 37 is connected to a coaxial waveguide 37a having a circular cross section extending upward from the opening 36 of the shield lid 34, and an upper end portion of the coaxial waveguide 37a via a mode converter 40. And a rectangular waveguide 37b extending in the horizontal direction. The mode converter 40 between the rectangular waveguide 37b and the coaxial waveguide 37a has a function of converting the microwave propagating in the TE mode in the rectangular waveguide 37b into the TEM mode. An inner conductor 41 extends in the center of the coaxial waveguide 37 a, and a lower end portion of the inner conductor 41 is connected and fixed to the center of the planar antenna member 31. Thereby, the microwave is uniformly and efficiently propagated to the planar antenna member 31 through the inner conductor 41 of the coaxial waveguide 37a.

  Each component of the microwave plasma processing apparatus 100 is connected to and controlled by a process controller 50 having a microprocessor (computer). The process controller 50 includes a user interface 51 including a keyboard that allows an operator to input commands to manage the plasma processing apparatus 100, a display that visualizes and displays the operating status of the plasma processing apparatus 100, and the like. A control program for realizing various processes executed by the processing apparatus 100 under the control of the process controller 50 and a program for causing each component of the plasma processing apparatus 100 to execute processes according to the processing conditions, that is, a recipe are stored. The storage unit 52 is connected. The recipe is stored in a storage medium in the storage unit 52. The storage medium may be a hard disk or semiconductor memory, or may be portable such as a CDROM, DVD, flash memory or the like. Moreover, you may make it transmit a recipe suitably from another apparatus via a dedicated line, for example.

  Then, if necessary, an arbitrary recipe is called from the storage unit 52 by an instruction from the user interface 51 and is executed by the process controller 50, so that a desired process in the plasma processing apparatus 100 can be performed under the control of the process controller 50. Is performed.

Next, the microwave transmission plate 28 will be described in detail.
As shown in FIG. 3A, the microwave transmitting plate 28 has an uneven shape in which convex portions 42a and concave portions 42b are alternately formed in a region including a portion corresponding to the peripheral portion of the wafer W on the microwave transmitting surface. A portion having the portion 42 and corresponding to the central portion of the wafer W is a flat portion 43. And the convex part 42a and the recessed part 42b of the uneven | corrugated-shaped part 42 have comprised the concentric form as shown in FIG.3 (b). The concavo-convex portion 42 functions to suppress the formation of standing waves formed in the radial direction in the microwave transmission plate 28, increase the plasma density, and make the plasma distribution uniform. Therefore, the plasma density (ion density) of the portion corresponding to the peripheral portion of the wafer W on which the uneven portion 42 is formed is higher than that of the flat portion 43.

  The uneven portion 42 may be provided in a portion including a region from the portion where the ion distribution at the peripheral portion of the wafer W starts to become lower than the central portion of the wafer W to the edge of the wafer W. That is, the tendency of the ion distribution to be convex is made uniform by raising the ion density at the peripheral portion, and the portion of the wafer W that does not need to increase the ion density is made to correspond to the flat portion 43. From such a viewpoint, as shown in FIG. 4, it is preferable that b / a be 50 to 80%, where a is the diameter of the wafer W and b is the diameter of the flat portion 43. In other words, by making the width of the concavo-convex portion 42 at the peripheral portion 20 to 50% of the radius of the wafer W, the ion distribution can be effectively made uniform. Further, from the viewpoint of efficiently eliminating the standing wave, the width of the convex portion 42a is preferably 4 to 23 mm, the width of the concave portion 42b is preferably 3 to 22 mm, and the height of the convex portion 42a is preferably 1 to 10 mm. More preferably, the width of the convex portion 42a is 6 to 14 mm, the width of the concave portion 42b is 5 to 13 mm, and the height of the convex portion 42a is 3 to 8 mm. Further, the uneven portion 42 of the microwave transmitting plate 28 is preferably formed to the end of the microwave transmitting surface excluding the attachment margin of the microwave 28, and the area of the uneven portion 42 is 100%. In this case, the area of the flat portion 43 is preferably 20 to 40%.

The microwave plasma processing apparatus 100 is suitable for a plasma oxidation process, and particularly suitable for an oxidation process of a silicon nitride (SiN) film that requires a relatively high energy plasma process by ion assist in addition to radicals. As a preferable example of such an oxidation treatment of the silicon nitride film, an oxidation treatment of the nitride film between the floating gate and the control gate of the nonvolatile memory element as shown in FIG. 5 can be mentioned. That is, in this memory element, a tunnel oxide film 102 is formed on the main surface of the Si substrate 101, and a floating gate 104 made of polysilicon is formed thereon. On the floating gate 104, for example, an oxide film 105 is formed. An ONO insulating film 108 made of a nitride film 106 and an oxide film 107 is formed, and a control gate 109 made of polysilicon or a laminated film of polysilicon and tungsten silicide is formed on the insulating film 108. An insulating layer 110 such as SiN or SiO ₂ is formed on the control gate 109, and a sidewall oxide film 111 is formed on the sidewalls of the floating gate 104 and the control gate 109 by oxidation treatment. The oxide film 105 of such a nonvolatile memory element is formed by thermal CVD, plasma CVD, plasma oxidation treatment, or the like, and the nitride film 106 is formed by thermal CVD or plasma CVD. In forming the oxide film 107 on the nitride film 106, the microwave plasma processing apparatus 100 of this embodiment can be suitably used.

  When an oxide film is formed by performing plasma oxidation treatment on such a silicon nitride (SiN) film, first, the gate valve 26 is opened and the wafer W on which the nitride film to be oxidized is formed from the loading / unloading port 25 is chambered. It is carried into 1 and placed on the susceptor 2.

Then, Ar gas and O ₂ gas are introduced from the Ar gas supply source 17 and the O ₂ gas supply source 18 of the gas supply system 16 into the chamber 1 through the gas introduction member 15 at a predetermined flow rate, and a predetermined processing pressure is obtained. To maintain. At this time, since the binding energy of SiN is 3.5 eV, which is higher than 2.3 eV of Si—Si bond, in a relatively high pressure region where radicals such as the direct oxidation process of the Si substrate are dominant. Oxidation does not proceed easily in the process. Therefore, in order to utilize ion energy, it is preferable to perform the oxidation treatment under a low pressure / low oxygen concentration condition in which the treatment pressure is relatively low and the O ₂ gas concentration is low.

Specifically, the processing pressure in the chamber is preferably 1.3 to 665 Pa, more preferably 1.3 to 266.6 Pa, and desirably 1.3 to 133.3 Pa. Moreover, the ratio (flow rate ratio, ie, volume ratio) of oxygen in the processing gas is preferably 0.5% or more and less than 20%, more preferably 0.5 to 5%, and preferably 0.5 to 2.5%. The flow rate of the processing gas is Ar gas: 0 to 5000 mL / min, preferably 0 to 1500 mL / min (sccm), O ₂ gas: 1 to 500 mL / min, preferably 1 to 50 mL / min (sccm), The ratio of oxygen to the total gas flow rate can be selected to be the above value.

In addition to Ar gas and _{O 2} gas from the Ar gas supply source 17 and the _{O 2} gas supply source 18 may be a _{H 2} gas supply source 19 for introducing a _{H 2} gas at a predetermined ratio. By supplying H ₂ gas, the oxidation rate in the plasma oxidation process can be improved. This is because OH radicals are generated by supplying H ₂ gas, which contributes to the improvement of the oxidation rate. In this case, the ratio of H ₂ is preferably 0.1 to 10% with respect to the total amount of the processing gas, more preferably 0.1 to 5%, and preferably 0.1 to 2%. . The flow rate of H ₂ gas is preferably 0.5 to 650 mL / min (sccm), more preferably 0.5 to 20 mL / min (sccm).

  In addition, process temperature can be made into the range of 200-800 degreeC, and 400-600 degreeC is preferable.

  Next, the microwave from the microwave generator 39 is guided to the waveguide 37 through the matching circuit 38. The microwave is supplied to the planar antenna member 31 through the rectangular waveguide 37b, the mode converter 40, and the coaxial waveguide 37a sequentially. The microwave propagates in the rectangular waveguide 37b in the TE mode, and the TE mode microwave is converted into the TEM mode by the mode converter 40, and the coaxial waveguide 37a is directed toward the planar antenna member 31. Propagated and radiated from the planar antenna member 31 to the space above the wafer W in the chamber 1 through the microwave transmitting plate 28. At this time, the power of the microwave generator 39 is preferably 0.5 to 5 kW.

  When a high-energy plasma containing ions as described above is formed by using such a microwave, if a conventional flat microwave transmission plate is used, the ion density at the center of the wafer W is high and the ion density at the periphery is high. Tend to be lower. On the other hand, in plasma dominated by radicals, concentric concavities and convexities are formed on the microwave transmission plate to prevent the formation of standing waves in the in-plane direction of the microwave transmission plate. It is known that high-density plasma can be formed, and as shown in FIG. 6A, an attempt is made to form an uneven portion 42 on almost the entire transmission surface of the microwave transmission plate 28. However, when a high-energy plasma containing ions is formed using a microwave plasma processing apparatus using such a microwave transmission plate, as shown in FIG. Although it is uniform, the ion tends to have a distribution in which the ion density is high in the central portion and the ion density is low in the peripheral portion, and it is difficult to perform uniform oxidation treatment.

  On the other hand, as in the present embodiment, the concavo-convex portion 42 is formed in the portion of the microwave transmitting plate 28 corresponding to the peripheral portion of the wafer W on the microwave transmitting surface, and the portion corresponding to the central portion of the wafer W. As shown in FIG. 6 (b), the ion density can be increased only in the portion corresponding to the peripheral portion of the wafer W where the ion density is desired to be increased. The nitride film can be subjected to uniform oxidation treatment. For this reason, the uniformity of the formed oxide film can be increased.

Next, a description will be given of the result of an actual oxidation process using the microwave plasma processing apparatus of the present invention.
First, using the apparatus of FIG. 1, a plasma oxidation process was performed on the SiN film formed by CVD under the following conditions, and the surface of the SiN film was oxidized to form an oxide film.
・ Processing pressure: 80Pa
Gas flow rate: Ar / O ₂ / H ₂ = 500/5 / 1.5 (mL / min (sccm))
・ Processing time: 180 sec
・ Microwave power: 4000W
・ Temperature: 600 ℃

  For comparison, an oxide film was formed by oxidizing the surface of the SiN film under the same conditions using an apparatus (comparative apparatus) provided with a concavo-convex portion on substantially the entire transmission surface of the microwave transmission plate.

As a result, the following results were obtained.
<Invention Device>
-Average thickness of oxide film: 8.72 nm
-Film thickness fluctuation range: 1.34 nm
-Film thickness variation (range / 2 x average): 7.7%
<Comparison device>
-Average thickness of oxide film: 9.26 nm
-Film thickness fluctuation range: 3.88nm
-Film thickness variation (range / 2 x average): 21.5%

Next, as a result of forming an oxide film on the surface of the bare Si wafer under the same conditions using the apparatus of the present invention and the apparatus (comparative apparatus) in which the concavo-convex portion was formed on the entire transmission surface of the microwave transmission plate, the following results were obtained. It became so.
<Invention Device>
-Average thickness of oxide film: 11.26 nm
-Film thickness fluctuation range: 0.85nm
-Film thickness variation (range / 2 x average): 3.8%
<Comparison device>
-Average thickness of oxide film: 12.48 nm
-Film thickness variation range: 1.12 nm
・ Thickness variation (range / 2 × average): 4.5%

  From the above results, when an oxide film is formed by oxidizing the surface of a bare Si wafer, sufficient film thickness uniformity can be obtained even if a comparative apparatus is used, whereas an oxide film is formed on the surface of the SiN film. In the case of forming, the variation in the oxide film thickness becomes extremely large in the comparison device, but it was confirmed that the film thickness uniformity was remarkably improved by using the device of the present invention.

As a result of further examination of conditions using the apparatus of the present invention, it was confirmed that the following conditions were the best.
・ Processing pressure: 80Pa
Gas flow rate: Ar / O ₂ / H ₂ = 500/5 / 0.7 (mL / min (sccm))
・ Processing time: 180 sec
・ Microwave power: 3600W
・ Temperature: 600 ℃

The oxide film at this time was as follows.
-Average thickness of oxide film: 7.16 nm
-Film thickness fluctuation range: 0.94 nm
-Film thickness variation (range / 2 x average): 6.6%

When an oxide film was formed by subjecting a bare Si wafer to oxidation under the same conditions, the following results were obtained.
-Average thickness of oxide film: 9.37 nm
-Film thickness fluctuation range: 0.72 nm
・ Thickness variation (range / 2 × average): 3.9%

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. For example, in the above-described embodiment, the case where the present invention is applied when forming the ONO insulating film of the nonvolatile memory element as the oxidation treatment of the silicon nitride (SiN) film is illustrated, but the present invention is not limited to this. In addition, although the case where the apparatus of the present invention is applied to the oxidation treatment of the nitride film has been shown, it can be applied to the oxidation treatment of other films as long as the oxidation treatment is performed using the RLSA type microwave plasma processing apparatus. It is.

1; chamber (processing room)
2; susceptor 3; support member 5; heater 15; gas introduction member 16; gas supply system 17; Ar gas supply source 18; O ₂ gas supply source 19; H ₂ gas supply source 23; exhaust pipe 24; Loading / unloading port 26; Gate valve 28; Microwave transmission plate 29; Seal member 31; Planar antenna member 32; Microwave radiation hole 37; Waveguide 37a; Coaxial waveguide 37b; Rectangular waveguide 39; 40; Mode converter 42; Uneven portion 42a; Convex portion 42b; Concavity 43; Flat portion 106; Nitride film 107; Oxide film W ... Wafer (substrate)

Claims (2)

A mounting table for mounting the object to be processed is provided in a chamber having a ceiling wall made of a microwave transmitting plate made of a dielectric and having a lower surface serving as a microwave transmitting surface. A microwave plasma processing apparatus that forms plasma by waves and performs plasma processing on an object to be processed placed on the mounting table by the plasma,
The microwave transmitting plate is provided to face the mounting table, and corresponds to a region from the microwave transmitting surface to the edge of the processing object at the periphery of the processing object placed on the mounting table. The microwave plasma processing apparatus characterized by having a concavo-convex portion in a portion to be processed, and a portion corresponding to the central portion of the object to be processed being a flat portion.   2. The micro of claim 1, wherein the concave and convex portions suppress a standing wave in a radial direction in the microwave transmission plate to increase an ion density in a portion corresponding to a peripheral portion of the object to be processed. Wave plasma processing equipment.

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