JP4974318B2 - Microwave plasma processing apparatus and processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a microwave-excited plasma processing apparatus (hereinafter referred to as a microwave plasma processing apparatus) and a plasma processing method using this apparatus, and in particular, 0.5 W / cm.²~ 20W / cm²A microwave plasma processing apparatus having a microwave introduction window with a high power density capable of film formation, etching, improvement / modification of film composition, and ashing on a substrate which is a processing object in semiconductor LSI fabrication The present invention relates to a microwave plasma processing apparatus and a plasma processing method using this apparatus.
[0002]
[Prior art]
In recent years, with the miniaturization of devices in semiconductor LSIs and the increase in diameter of wafers, single wafer processing has become the mainstream for fine processing of wafers. Among them, plasma sources such as DC and high frequency excitation are used in plasma processing such as CVD, etching, and ashing. Further, ECR (electron cyclotron resonance) is used in a plasma source using a microwave.
As described above, in the case of plasma excited by high frequency or ECR, it is necessary to apply a magnetic field in order to generate high-density plasma, and it is difficult to generate uniform plasma with a large diameter. In addition, since the plasma potential is as high as about 20 eV, metal contamination is generated by sputtering the chamber wall. Further, since the ion irradiation energy for the floating substrate is as high as 10 eV or more, the substrate is damaged. It was.
[0003]
Therefore, by using antenna means such as a radial line slot antenna (hereinafter referred to as RLSA), a microwave is introduced into the vacuum atmosphere from the slot via a dielectric, and a strong microwave electric field is generated to generate surface wave plasma. A generation method has been developed. For example, Japanese Patent Laid-Open No. 2000-294548 describes a method in which the thickness of the dielectric window is continuously changed. In this method, circularly polarized microwaves are radiated by the slot pattern of the antenna, so that a uniform plasma can be generated with a large aperture, and because the frequency is high, low temperature and high density plasma can be generated, and high speed is achieved. It is said that high-quality plasma processing can be realized.
[0004]
[Problems to be solved by the invention]
In the prior art described in Japanese Patent Laid-Open No. 2000-294548, the microwave propagates in a specific mode through the waveguide and is radiated from the antenna means to create a microwave electric field in the vacuum vessel, thereby forming a plasma. However, when the plasma becomes dense, energy absorption occurs and at the same time, the microwave is reflected on the plasma surface, and an unspecified number of modes are generated between the antenna surface sandwiching the dielectric and the plasma excitation part. In this way, when the thickness of the dielectric window is continuously changed and the surface on the plasma processing chamber side is conical, there is a problem in mode stability and the like.
[0005]
This reflected wave is divided into a mode that is attenuated as a cavity resonator between the antenna surface and the plasma excitation part, and a mode that is amplified. However, when the reflected wave interferes with the introduced microwave and attenuates, the power supply to the plasma is not stable, and the plasma becomes unstable. As a result, the reflected wave could not be suppressed by the tuner, and the auto-matching always fluctuated greatly and the plasma flickered.
[0006]
In addition, since the microwave has a high frequency, the power tends to concentrate on a part of the plasma as the part of the plasma has a lower impedance.
In addition, a surface wave mode is formed in the radial direction, which is also the most stable state due to the combination of a number of modes. There was a problem that the reproducibility of was not possible. The surface wave mode also greatly depends on the process pressure, and there is a phenomenon that the plasma density distribution is reversed between the central portion and the outer peripheral portion at low pressure (about 5-100 Pa) and high pressure (100 Pa-).
[0007]
An object of the present invention is to solve the above-mentioned problems of the prior art, and it is possible to obtain a uniform plasma density on the substrate surface, and to perform high-efficiency plasma processing with high reliability and stability. A processing apparatus and a processing method using the apparatus are provided.
[0008]
[Means for Solving the Problems]
  The microwave-excited plasma processing apparatus of the present invention includes an exhaust means for depressurizing the inside of the microwave plasma processing container, a gas supply means for supplying a gas for exciting plasma in the processing container, A microwave transmitting dielectric window provided on the wall surface, antenna means provided on the microwave introduction side of the dielectric window, and microwave generating means provided on the upstream side of the antenna means, In the microwave plasma processing apparatus configured such that the substrate is placed in the processing container so as to face the dielectric window, a plasma excitation region is directly provided on an outer peripheral portion of the surface of the dielectric window on the processing container side. A ring-shaped sleeve is provided so as not to contact the metal surface of the processing vessel wall, and the center portion of the dielectric window is provided.Provided with a convex portion projecting to the processing container side or the microwave introduction side,Thickness ofInviteIt is characterized by being about 1/4 of the wavelength of the microwave in the electric body.
  The microwave-excited plasma processing apparatus of the present invention includes an exhaust means for decompressing the inside of the microwave plasma processing container, a gas supply means for supplying a gas for exciting plasma into the processing container, and the processing A microwave transmitting dielectric window provided on a wall surface of the container; an antenna means provided on the microwave introduction side of the dielectric window; and a microwave generating means provided on the upstream side of the antenna means. In the microwave plasma processing apparatus configured such that a substrate is placed in the processing container so as to face the dielectric window, a plasma excitation region is formed on an outer peripheral portion of the surface of the dielectric window on the processing container side. Is provided with a ring-shaped sleeve so that it does not directly contact the metal surface of the processing vessel wall, and the dielectric window has a convex having a thickness of about 1/4 of the wavelength of the microwave in the dielectric. The is characterized in that concentrically arranged.
[0009]
  The microwave-excited plasma processing apparatus of the present invention includes an exhaust means for decompressing the inside of the microwave plasma processing container, a gas supply means for supplying a gas for exciting plasma into the processing container, and the processing A microwave transmitting dielectric window provided on a wall surface of the container; an antenna means provided on the microwave introduction side of the dielectric window; and a microwave generating means provided on the upstream side of the antenna means. In the microwave plasma processing apparatus configured such that a substrate is placed in the processing container so as to face the dielectric window, a plasma excitation region is formed on an outer peripheral portion of the surface of the dielectric window on the processing container side. Is provided with a ring-shaped sleeve so that it does not directly contact the metal surface of the processing vessel wall, and a concentric convex portion is formed on the dielectric window, which is an integral multiple of ½ wavelength in the radial direction of the dielectric window. Characterized by providing discontinuously diameter.in this case,in frontConvexityPartSet the thickness to about 1/4 of the wavelength of microwaves in the dielectric.
[0010]
  BookAccording to the microwave plasma processing apparatus of the invention, a large-diameter dielectric window, for example, a dielectric window having a diameter of 250 mm or more, or an area equal to or larger than a circle having a diameter of 250 mm, is used. Introducing wavesthingIs possible.
[0011]
  The microwave plasma processing method of the present invention supplies a raw material gas for exciting plasma by a gas supply means into a microwave plasma processing vessel, exhausts the raw material and a reaction byproduct gas by an exhaust pump, and depressurizes the inside of the vessel. Then, the microwave oscillated and amplified by the microwave generating means is introduced into the antenna means and radiated through the slot, and the radiated microwave is passed through the microwave transmission window in a vacuum atmosphere.AboveIt is introduced into the processing container, and plasma is generated in the processing container by the electromagnetic field generated by this microwave.AboveMicrowave plasma treatment of the substrate provided facing the dielectric windowIn the microwave plasma processing methodThe plasma processing is performed using the plasma processing apparatus having the dielectric window configured as described above. The gas pressure in the processing container is preferably 0.1 Pa to 1000 Pa, and the frequency of the microwave applied to the electrode is preferably 2 GHz to 10 GHz. When the gas pressure is less than 0.1 Pa and exceeds 1000 Pa, it is difficult to start and maintain the discharge. If the frequency is less than 2 GHz, a desired plasma density cannot be obtained, and if it exceeds 10 GHz, the equipment for power amplification becomes large and the handling is difficult.
[0012]
According to the present invention, in the microwave plasma processing apparatus, as described above, the surface shape and thickness of the dielectric window are adjusted in-plane, and the supplied microwave and reflected wave are amplified in the resonator. By forming a non-region, the power can be efficiently concentrated in the region to be amplified, and the occurrence of mode jumps can be suppressed by limiting the surface wave modes that are stable in space. A highly efficient and efficient process can be performed.
Further, the plasma is excited in a region that is only a few millimeters away from the surface of the dielectric window, and reaches the opposing substrate by diffusion. The attenuation of the plasma density due to this diffusion is approximately proportional to the square of the distance. A uniform plasma density can be obtained on the substrate surface by providing a step in the shape of the dielectric window so that the dielectric portion corresponding to the low plasma density region approaches the substrate side.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a microwave plasma processing apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a schematic configuration of a microwave plasma processing apparatus for a semiconductor substrate using RLSA having a microwave transmission window having a ring-shaped sleeve on the outer peripheral portion as a first embodiment of the present invention. It is sectional drawing.
[0014]
In FIG. 1, 101 is a processing container for performing plasma processing, 102 is a coaxial waveguide converter and antenna means, 103 is a slot for radiating microwaves, 104 is a dielectric window for transmitting microwaves, and 105 is for etching or formation. Plasma formed by a microwave electric field above the substrate to form a film, 106 is a magnetron that oscillates microwaves, 107 is an isolator, 108 is a 4E tuner, 109 is a waveguide, and 110 is a plasma forming gas supply means , 111 is an exhaust pump, 112 is a pressure adjusting valve for adjusting the pressure in the container 101, 113 is a substrate to be plasma-treated, 114 is an electrode for holding the substrate, and 115 is for the substrate electrode 114 and the substrate 113 as required. A high frequency power source for applying a high frequency, and a matching unit 116 for adjusting a high frequency impedance A. A ring-shaped sleeve 117 is formed on the outer peripheral portion of the dielectric window 104, that is, a portion away from the center portion so that the plasma excitation region does not directly contact the metal surface of the processing vessel wall.
[0015]
Hereinafter, an outline of a plasma processing method performed using the apparatus shown in FIG. 1 will be described.
A gas for exciting the plasma 105 is supplied into the processing container 101 by the gas supply means 110, the exhaust pump 111 is operated, the raw material and the reaction byproduct gas are exhausted to reduce the pressure in the processing container 101, and the processing container 101 The internal process pressure is adjusted by the pressure regulating valve 112. The microwave oscillated and amplified by the magnetron 106 is introduced into the antenna 102 through the 4E tuner 108 and radiated from the slot 103. At this time, the reflected wave is returned to the processing container 101 side by the 4E tuner 108, but the reflected wave that cannot be adjusted is absorbed by the isolator 107 and prevented from returning to the magnetron 106. The microwave radiated from the slot 103 is introduced into the processing container 101 in a vacuum atmosphere through the dielectric window 104, and a plasma 105 is formed in the processing container 101 by the electromagnetic field generated by the microwave.
[0016]
When the density of the formed plasma 105 exceeds the cutoff frequency of the microwave near the dielectric window 104, the penetration depth of the microwave is several millimeters, and some energy is in the range of several millimeters in the plasma. It is absorbed by 105 and the rest is reflected. The density distribution of the generated plasma 105 can be uniformly adjusted on a plane depending on the slot pattern, but greatly depends on the pressure in the processing vessel 101 and the shape of the dielectric window 104 at that time. The plasma 105 generated in this manner reaches the substrate 113 by diffusion, and a desired plasma treatment can be performed on the substrate 113.
[0017]
FIG. 2 shows an outline of an apparatus provided with a microwave transmission window provided with a convex portion on a surface on the antenna means side in a configuration of a microwave plasma processing apparatus for a semiconductor substrate using RLSA as a second embodiment of the present invention. It is sectional drawing which shows this structure.
In this apparatus, the dielectric window 204 constituting the microwave introduction window is a concentric area, that is, an area on the atmosphere side (microwave introduction side) in a predetermined distance from the center of the circular dielectric window. A dielectric window in which a convex portion (diameter: D2) is provided on the surface and the thickness of the portion is changed is used. Other configurations are the same as those shown in FIG. 1, and the same reference numerals in FIG. 1 denote the same configurations unless otherwise specified.
[0018]
The dielectric window 204 that is a microwave introduction window can be made of the same material as the dielectric window 104. When a quartz plate having a thickness of 50 mm is used, for example, in the region (D2) up to φ = 95 mm, the atmosphere side of the dielectric window 204 is convex, and the thickness of the convex portion is 60 mm. For example, the thickness of the dielectric window immediately above a silicon substrate having a diameter (Dw) of 200 mm is the thickness of the region located immediately above the region in which the radius of the substrate ranges from 0 mm to 47.5 mm (D2X1 / 2). Becomes 60 mm, and the thickness in other regions becomes 50 mm.
[0019]
FIG. 5 shows a configuration of a microwave plasma processing apparatus for a semiconductor substrate using RLSA as a third embodiment of the present invention, which includes a microwave transmission window provided with a convex portion on the surface on the processing container 101 side. It is sectional drawing which shows a schematic structure.
In this apparatus, the dielectric window 504 constituting the microwave introduction window is a concentric region, that is, a region on the vacuum side in the region from the center of the dielectric window to a predetermined equidistant distance as opposed to the case of FIG. A dielectric window is used in which a convex portion (diameter: D5) is provided on the surface and the thickness of the portion is changed. Other configurations are the same as those shown in FIG. 1, and the same reference numerals in FIG. 1 denote the same configurations unless otherwise specified.
[0020]
The dielectric window 504 which is a microwave introduction window can be made of the same material as the dielectric window 104. When a quartz plate having a thickness of 44 mm is used, for example, the vacuum side of the dielectric window 504 is convex in the region (D5) up to φ = 60 mm, and the thickness of the convex portion is 60 mm. For example, the thickness of the dielectric window immediately above a silicon substrate having a diameter (Dw) of 200 mm is such that the thickness of the region located immediately above in the region where the radius of the substrate is in the range from 0 mm to 30 mm (D5X1 / 2). 60 mm, and the thickness in other regions is 44 mm. Further, in the region (D5X1 / 2) where the radius of the substrate is 0 mm to 30 mm, the distance (L52) from the substrate to the dielectric plate is 40 mm, and in the other regions, the distance (L51) is 56 mm.
[0021]
  FIG. 6 shows a configuration of a microwave plasma processing apparatus for a semiconductor substrate using RLSA as a fourth embodiment of the present invention.Antenna means sideProtrusion on the surface of theOneCorresponds to the convex partOn the processing container 101 sideIt is sectional drawing which shows the schematic structure of the apparatus provided with the microwave permeation | transmission window which provided the recessed part in the area | region.
  In this apparatus, as the dielectric window 604 constituting the microwave introduction window, a convex portion on the surface on the microwave introduction side, a vacuum side in a concentric region, that is, a region from the center of the dielectric window to a predetermined equal distance A dielectric window is used which is processed so as to be provided with a recess on the surface thereof, and the thickness of the dielectric window itself is the same in any region. Other configurations are the same as those shown in FIG. 1, and the same reference numerals in FIG. 1 denote the same configurations unless otherwise specified.
[0022]
The dielectric window 604 that is a microwave introduction window can be made of the same material as the dielectric window 104. When a quartz plate having a thickness of 50 mm is used, for example, the dielectric window 604 has a vacuum side in the region up to φ = 60 mm (D6), and the dielectric directly above the substrate having a diameter (Dw) of 200 mm from the substrate 613. Regarding the distance to the body window, the distance (L62) is 65 mm in the region (D6) where the radius of the substrate is 0 mm to 30 mm, and the distance (L61) is 60 mm in the other regions.
Although the pressure in the said plasma processing container changes with process conditions, generally a desired effect can be acquired in the range of 5 Pa-1000 Pa. The distance (L11, L21, L51, L52, L61, L62) between the lower surface of the dielectric window and the upper surface of the substrate is generally in the range of 30 mm to 120 mm depending on the relationship of plasma density, oxidation rate, film thickness distribution uniformity, etc. It is preferable to make it.
[0023]
As described above, when the thickness of the dielectric window is changed within a predetermined range, it is desirable to set the thickness to about λg / 4 of the wavelength (λg) of the microwave in the dielectric. Since the electric field strength of the microwaves is sown according to the standing wave condition existing there, if the central part is the optimum thickness, the plasma density will be low at the thin outer peripheral part. This is because the electric field strength does not always increase in the thin portion simply by reducing the thickness of the dielectric window. Therefore, as in the present invention, it is effective to define the thickness of the central portion and provide a step of λg / 4 of the microwave wavelength in the dielectric. The range in which the thickness of the dielectric window is changed or the stepped range may be arranged in a concentric ring shape, or may be arranged in an appropriately distributed manner.
[0024]
In order to generate a high-density plasma, the frequency of the microwave to be input is generally appropriately selected from the range of 2 GHz to 10 GHz, and the plasma density directly below the dielectric window is the microwave cut-off density. In order to achieve this, the input power is preferably 1 W / cm relative to the area of the lower surface of the dielectric window.²~ 5W / cm²It is preferable to carry out the process by appropriately selecting from the above range. Process gases include deposition films (insulating films, semiconductor films, metal films, etc.), thin film formation by CVD (silicon-based semiconductor thin films, silicon compound-based thin films, metal thin films, metal compound thin films, etc.), substrate surface Various known gases can be appropriately selected and used depending on the processes such as etching, ashing removal of organic components on the substrate surface, oxidation treatment on the substrate surface, and cleaning of organic substances on the substrate surface. For example, one or more known gases may be added during the process to a total of at least 8.5 × 10^-2Pa · m³/ Sec or more may be introduced.
[0025]
The substrate support stage temperature varies depending on each process such as etching and film formation, but in general, it may be appropriately selected from the range of −40 ° C. to 600 ° C.
The substrate to be processed is not particularly limited. For example, a glass substrate, a plastic substrate, an AlTiC substrate, or the like can be used without being limited to a semiconductor substrate.
The dielectric constituting the microwave introduction window is not particularly limited as long as the material has a sufficient mechanical strength and a very low dielectric loss so that the microwave transmittance is sufficiently high. For example, quartz, Alumina (sapphire), aluminum nitride, silicon nitride, fluorocarbon polymer, or the like can be used.
[0026]
【Example】
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
Example 1
Using the apparatus of the present invention shown in FIGS. 1 and 2, Kr / O₂The measurement of the thickness of the oxide film on the processed wafer after the plasma is generated and the silicon substrate is directly oxidized will be described.
First, the oxidation treatment of the silicon substrate performed using the apparatus shown in FIG. 1 will be described. After the dielectric window 104 is installed in the microwave introduction window and the silicon substrate 113 is set in the vacuum processing vessel 101, the microwave is output from the magnetron 106 to generate plasma under the following conditions. The thickness of the oxide film on the silicon substrate 113 was measured with an ellipsometer.
[0027]
As the dielectric window 104, a quartz plate having a diameter of 380 mm (vacuum container side: 350 mm) and a thickness of 50 mm (dielectric constant 3.8, dielectric loss <1.0 × 10^-4@ 2.45 GHz). Microwave frequency: 2.45 GHz, output: 2.5 kW (about 2.6 W / cm²), The hot plate temperature is maintained at 400 ° C., the distance (L11) between the upper surface of the silicon substrate 113 and the lower surface of the dielectric window 104 is 60 mm, and the silicon substrate 113 on the substrate electrode 114 has a high frequency bias. The plasma treatment was performed without applying. As a plasma excitation gas, Kr is 0.5 Pa · m.³/ Sec, O₂1.7X10^-2Pa · m³/ Sec, and the pressure in the processing vessel 101 was adjusted to 133 Pa by the pressure adjustment valve 112, and the wafer was subjected to plasma oxidation treatment by discharging for 10 minutes.
Further, the plasma treatment was performed under the same conditions as described above except that the pressure in the processing vessel 101 was adjusted to 80 Pa by the pressure regulating valve 112.
[0028]
As a result, the thickness distribution of the silicon oxide film formed on the substrate was almost concentric. FIG. 3 shows the average thickness in the radial direction. From FIG. 3, it can be seen that the outer peripheral part on the substrate is thicker than the central part and the oxidation rate is faster at 80 Pa, whereas the oxidation rate at the central part is faster at 133 Pa. .
[0029]
Next, using the apparatus shown in FIG. 2, the silicon substrate 213 was subjected to plasma oxidation under the same conditions as in the apparatus shown in FIG. 1, and the thickness of the oxide film (silicon oxide film) was measured using an ellipsometer.
As a result, the thickness distribution of the silicon oxide film formed on the substrate became substantially concentric and uniform. FIG. 4 shows the average thickness in the radial direction. Comparing this result with FIG. 3, from the film thickness distribution of the oxide film at 80 Pa, the outer peripheral portion is still faster than the central portion, but the difference is small, and the distribution uniformity is improved. You can see that Also, the overall oxide film formation rate is increased. From this, it can be seen that by changing the shape of the dielectric window, the power of the microwave can be efficiently supplied to the plasma, and the distribution uniformity is improved. In the case of 133 Pa, the oxidation rate is generally faster, and the same can be said as in the case of 80 Pa.
[0030]
(Example 2)
Using the apparatus shown in FIG. 5, Kr / O₂The measurement of the thickness of the oxide film on the processed wafer after the plasma is generated and the silicon substrate is directly oxidized will be described.
The silicon substrate 513 was subjected to plasma oxidation under the same conditions as in the case of the apparatus shown in FIG. 1 described in Example 1, and the thickness of the oxide film was measured using an ellipsometer.
[0031]
As a result, the thickness distribution of the silicon oxide film formed on the substrate became substantially concentric and uniform. FIG. 7 shows the average thickness in the radial direction. Comparing this result with FIG. 3, it can be seen from the film thickness distribution of the oxide film at 80 Pa that the oxidation rate is faster in the central portion than in the outer peripheral portion, contrary to the case of FIG. This is because when the radius of the silicon substrate is in the range from 0 mm to 30 mm, the distance (L52) to the dielectric window (plasma generation region) is short, so the density of plasma reaching the substrate is in another range (distance: L51). This is because it is higher.
Therefore, by increasing the distance from the bottom surface of the dielectric window on the vacuum side to the substrate for each region, the film formation speed in that region increases, and by adjusting the distance, the film thickness distribution uniformity is improved. I can do it.
[0032]
(Example 3)
Using the apparatus shown in FIG. 6, Kr / O₂The measurement of the thickness of the oxide film on the processed wafer after the plasma is generated and the silicon substrate is directly oxidized will be described.
The silicon substrate 613 was subjected to plasma oxidation under the same conditions as in the case of the apparatus shown in FIG. 1 described in Example 1, and the thickness of the oxide film was measured with an ellipsometer.
[0033]
As a result, the thickness distribution of the silicon oxide film formed on the substrate became substantially concentric and uniform. FIG. 8 shows the average thickness in the radial direction. Comparing this result with FIG. 3, it can be seen from the film thickness distribution of the oxide film at 80 Pa that the oxidation rate in the central portion is improved and the uniformity is improved. On the other hand, at 133 Pa, on the contrary, the oxidation rate at the outer peripheral portion is improved and the uniformity is improved. At first glance, this contradicts the results of the above-described embodiment, but plasma tends to concentrate at the center even when the planar dielectric window 104 (FIG. 1) is used under a high pressure condition of 133 Pa. However, since the distance (L62) to the dielectric window (plasma generation region) is 5 mm far from the other region (distance: L61) in the central portion of the substrate as in the result in Example 2, the plasma reaching the substrate It is thought that the density became thinner than other ranges and the distribution was improved. Conversely, at a low pressure of 80 Pa, the plasma density tends to spread because the plasma density is thin, but by making a part of the surface where the surface wave is generated concave, plasma generation in the concave region increases, This is probably because the stable coupling mode is less affected by pressure conditions. For this reason, the spread of plasma is suppressed, and a distribution close to that in the case of high pressure conditions can be obtained.
[0034]
As described above, unevenness processing is performed on both sides of the dielectric window for each region, so that the microwave power can be intentionally concentrated in this region, making it possible to generate plasma with less pressure dependence and good uniformity. became.
In the above embodiment, the silicon substrate was subjected to plasma oxidation processing and an oxide film was formed using the microwave plasma processing apparatus shown in FIGS. 1, 2, 5 and 6, but the same plasma processing apparatus was used to fabricate the semiconductor LSI. It was possible to perform processes such as film formation, etching, film composition improvement / modification, ashing, etc. using a known thin film forming gas, etchant gas, ashing gas, etc. .
[0035]
【The invention's effect】
As described above in detail, according to the present invention, in the microwave plasma processing apparatus, the surface shape of the dielectric window and the thickness of the dielectric window are adjusted in-plane, and the supplied microwave and reflected wave are resonators. By forming a region that is amplified and a region that is not so, the power can be efficiently concentrated in the region that is amplified, and the mode jump can be achieved by limiting the surface wave mode that is stable in space. Therefore, a highly efficient process with high reliability and stability can be performed.
Further, the plasma is excited in a region within a few millimeters from the dielectric window, and reaches the opposing substrate by diffusion. The attenuation of the plasma density due to this diffusion is approximately proportional to the square of the distance. A uniform plasma density can be obtained on the substrate surface by providing a step so that the dielectric window in the low density region approaches the substrate side.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a microwave plasma processing apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of a microwave plasma processing apparatus according to a second embodiment of the present invention.
FIG. 3 is a graph showing an average radial thickness of a silicon oxide film formed using the apparatus shown in FIG. 1;
FIG. 4 is a graph showing an average radial thickness of a silicon oxide film formed using the apparatus shown in FIG.
FIG. 5 is a schematic cross-sectional view showing a schematic configuration of a microwave plasma processing apparatus according to a third embodiment of the present invention.
FIG. 6 is a schematic cross-sectional view showing a schematic configuration of a microwave plasma processing apparatus according to a fourth embodiment of the present invention.
7 is a graph showing an average thickness in the radial direction of a silicon oxide film formed using the apparatus shown in FIG.
8 is a graph showing the average thickness in the radial direction of a silicon oxide film formed using the apparatus shown in FIG.
[Explanation of symbols]
101 Plasma processing vessel 102 Coaxial waveguide converter and antenna
103 slot 104 dielectric plate
105 plasma 106 magnetron
107 Isolator 108 4E Tuner
109 Waveguide 110 Gas supply means
111 Exhaust pump 112 Pressure control valve
113 substrate 114 substrate electrode
115 High frequency power supply for substrate electrode 116 Matching device for substrate electrode
117 sleeve 204 dielectric plate
213 Substrate L21 Distance between dielectric plate and substrate
Dw Substrate range D2 Dielectric plate thickness change range
504 Dielectric plate 513 Substrate
L51 Distance between dielectric plate and substrate L52 Distance between dielectric plate and substrate (thickness changing portion) D5 Dielectric plate thickness change range
604 dielectric plate 613 substrate
L61 Distance between dielectric plate and substrate L62 Distance between dielectric plate and substrate (shape changing part) D6 Dielectric thickness change range

Claims (8)

Exhaust means for depressurizing the inside of the microwave plasma processing vessel, gas supply means for supplying a gas for exciting the plasma into the processing vessel, and a microwave transmitting dielectric provided on the wall of the processing vessel A window, antenna means provided on the microwave introduction side of the dielectric window, and microwave generation means provided on the upstream side of the antenna means, and facing the dielectric window in the processing container In the microwave plasma processing apparatus configured to be installed on the substrate,
A ring-shaped sleeve is provided on the outer peripheral portion of the surface of the dielectric window on the processing container side so that the plasma excitation region does not directly contact the metal surface of the processing container wall,
Providing a convex portion projecting to the processing container side or microwave introduction side at the center of the dielectric window ,
The microwave plasma processing apparatus, wherein the thickness of the convex portion is about 1/4 of the wavelength of the microwave in the dielectric. Exhaust means for depressurizing the inside of the microwave plasma processing vessel, gas supply means for supplying a gas for exciting the plasma into the processing vessel, and a microwave transmitting dielectric provided on the wall of the processing vessel A window, antenna means provided on the microwave introduction side of the dielectric window, and microwave generation means provided on the upstream side of the antenna means, and facing the dielectric window in the processing container In the microwave plasma processing apparatus configured to be installed on the substrate,
A ring-shaped sleeve is provided on the outer peripheral portion of the surface of the dielectric window on the processing container side so that the plasma excitation region does not directly contact the metal surface of the processing container wall,
The dielectric window, a microwave plasma processing apparatus, wherein a convex portion having approximately 1/4 of the thickness of the wavelength of the microwaves of the dielectric disposed concentrically Exhaust means for depressurizing the inside of the microwave plasma processing vessel, gas supply means for supplying a gas for exciting the plasma into the processing vessel, and a microwave transmitting dielectric provided on the wall of the processing vessel A window, antenna means provided on the microwave introduction side of the dielectric window, and microwave generation means provided on the upstream side of the antenna means, and facing the dielectric window in the processing container In the microwave plasma processing apparatus configured to be installed on the substrate,
A ring-shaped sleeve is provided on the outer peripheral portion of the surface of the dielectric window on the processing container side so that the plasma excitation region does not directly contact the metal surface of the processing container wall,
The concentric convex portions in the dielectric window, a microwave plasma processing apparatus characterized by comprising discontinuously said dielectric radially integer multiple of a half wavelength in diameter of the window. 4. The microwave plasma processing apparatus according to claim 3, wherein the thickness of the convex portion is about 1/4 of the wavelength of the microwave in the dielectric. The source gas for exciting the plasma is supplied into the microwave plasma processing vessel by the gas supply means, the source and reaction by-product gas are exhausted by the exhaust pump, the inside of the vessel is decompressed, and the microwave generation means oscillates and amplifies. Introduced microwaves into the antenna means and radiates through the slot, and the radiated microwaves are introduced into the processing vessel in a vacuum atmosphere through the microwave transmission window and processed by the electromagnetic field generated by the microwaves. In a microwave plasma processing method for generating plasma in a container and performing microwave plasma processing on a substrate provided facing the dielectric window,
As the dielectric window, an outer peripheral portion of the surface of the processing container side, such that the plasma excitation region is not in direct contact with the metal surface of the processing container wall has a ring-shaped sleeve, further said dielectric window the convex portion is provided which projects into the processing chamber side or microwave introducing side to the central portion, and includes a dielectric window that is about 1/4 of the microwave wavelength in the dielectric thickness of the front Kitotsu portion A microwave plasma processing method comprising performing plasma processing using a plasma processing apparatus. The source gas for exciting the plasma is supplied into the microwave plasma processing vessel by the gas supply means, the source and reaction by-product gas are exhausted by the exhaust pump, the inside of the vessel is decompressed, and the microwave generation means oscillates and amplifies. Introduced microwaves into the antenna means and radiates through the slot, and the radiated microwaves are introduced into the processing vessel in a vacuum atmosphere through the microwave transmission window and processed by the electromagnetic field generated by the microwaves. In a microwave plasma processing method for generating plasma in a container and performing microwave plasma processing on a substrate provided facing the dielectric window,
As the dielectric window, an outer peripheral portion of the surface of the processing container side, such that the plasma excitation region is not in direct contact with the metal surface of the processing container wall has a ring-shaped sleeve, further concentric convex the microwave plasma processing, characterized in that to perform plasma processing using a plasma processing apparatus having a discontinuously arranged dielectric window at an integer multiple of the diameter of the half wavelength in the radial direction of the dielectric window and parts Method. 7. The microwave plasma processing method according to claim 6 , wherein the thickness of the convex portion of the dielectric window is set to about 1/4 of the wavelength of the microwave in the dielectric. The micro gas according to any one of claims 5 to 7 , wherein the gas pressure in the processing container is 0.1 Pa to 1000 Pa, and the frequency of the microwave applied to the electrode is 2 GHz to 10 GHz. Wave plasma treatment method.

Images