JP2006295058A - Plasma cvd device and method for forming oxide film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma CVD device which can restrain the occurrence of damages to a processing body or an insulating film formed in the processing body, and can form the insulating film excellently on the processing body. <P>SOLUTION: The plasma CVD device comprises a vacuum envelope 10 which has a processing substrate 100 disposable internally, a plasma source antenna 20 for entering evanescent waves into the vacuum envelope 10, an upper gas introduction system 50 having an upper gas introduction pipe 51 for introducing a first gas containing at least one of a noble gas and an oxygen gas into the vacuum envelope 10, and a lower gas introduction system 60 having a lower gas introduction pipe 61 for introducing a second gas containing at least one of an organic silicon compound and an organic metal compound into the vacuum envelope 10. With this arrangement, the first gas and second gas are ionized with the evanescent waves, resulting in forming an insulating film 101 on the processing substrate 100. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma enhanced chemical vapor deposition (CVD) apparatus and an oxide film applied when an insulating film is formed in a manufacturing process of a semiconductor device such as a semiconductor integrated circuit device or a display device such as a liquid crystal display device. It relates to a method of forming.

  In the manufacturing process of semiconductor devices and liquid crystal display devices, conventionally, an insulating film is formed on a substrate to be processed using a parallel plate type high frequency plasma CVD (Plasma Enhanced Chemical Vapor Deposition) apparatus using an organic silicon compound as a process gas. A forming method is known (see, for example, Patent Document 1).

As a plasma processing apparatus and a microwave plasma generation apparatus, one that generates plasma by an evanescent wave that oozes when shielding or cutoff occurs has been proposed (for example, see Patent Documents 2 and 3). Furthermore, as a microwave plasma apparatus, an apparatus provided with a non-evanescent microwave applicator including means for controlling the shielding wavelength has been proposed (for example, see Patent Document 4).
JP-A-5-345831 Japanese Patent Laid-Open No. 10-247598 JP 2004-200113 A Special table 2001-518678 gazette

  By the way, when forming a silicon oxide film on a to-be-processed object, when an organic silicon compound gas is used as a process gas, a silicon oxide film having a good coverage can be obtained more easily than when a silane gas is used. This is because the organic silicon compound has a larger molecular volume than silane. That is, when an organic silicon compound gas is used as a process gas, an intermediate product obtained by decomposing an organic silicon compound by plasma also has a relatively large molecular volume. While migrating above, it adheres relatively uniformly to the surface of this object. Therefore, a silicon oxide film with good coverage is obtained.

  However, since the organosilicon compound contains an alkyl group or the like in its skeleton, carbon atoms contained in the carbon skeleton portion are likely to be mixed as impurities in the silicon oxide film when excessively decomposed. Therefore, there is a need for a plasma CVD apparatus in which the process gas is not excessively decomposed even when a gas such as an organic silicon compound is used as the process gas.

  Further, in the parallel plate type high-frequency plasma CVD apparatus described in Patent Document 1, plasma generated in the vacuum chamber spreads to a region where the object to be processed is disposed. Therefore, there is a problem that ion damage is easily caused on the surface of the object to be processed and the interface between the object to be processed and the insulating film.

  That is, when the plasma spreads to a region where the object to be processed is disposed, the object to be processed comes into contact with high-energy electrons, so that a sheath electric field that tends to increase according to the energy of the electrons increases. As the sheath electric field increases, the energy of ions incident on the object to be processed increases accordingly. As a result, ion damage tends to occur on the surface of the object to be processed and the interface between the object to be processed and the insulating film. End up.

  The present invention has been made based on such circumstances, and it is possible to satisfactorily form an insulating film on a target object while suppressing damage to the target object and the insulating film formed on the target object. It is an object of the present invention to provide a plasma CVD apparatus and an oxide film forming method capable of forming the film.

  The plasma CVD apparatus according to the first embodiment of the present invention has an electromagnetic wave source that generates an electromagnetic wave and an incident surface on which an evanescent wave that is an exuding wave of the electromagnetic wave is incident, and an object to be processed can be disposed therein. A processing container, a plasma source that generates plasma by making an evanescent wave incident on the inside of the processing container, and a first gas that is provided in the processing container and includes at least one of a rare gas and an oxygen gas; A first gas introduction system having a first gas introduction part to be introduced into the interior of the container; and a second gas provided in the processing container and containing at least one of an organosilicon compound and an organometallic compound. And a second gas introduction system having a second gas introduction unit that separates the first gas and introduces the gas into the processing container, and the first and second gases are separated by evanescent waves. And forms an insulating film on the target object by plasma Te.

  According to the plasma CVD apparatus, when a gas containing at least one of an organic silicon compound and an organometallic compound is used as the second gas, a source gas having a relatively low molecular weight such as silane gas is used. As compared with the above, an oxide film having better coverage can be formed.

  Moreover, according to the plasma CVD apparatus, the first gas and the second gas are separated and introduced into the processing container. Therefore, oxygen radicals can be efficiently generated in the processing container by introducing the first gas into the processing container from or near the region where electrons are accelerated by the electric field generated by the evanescent wave. Moreover, excessive decomposition | disassembly of 2nd gas can be suppressed by introduce | transducing 2nd gas into the inside of a processing container from the area | region where there is little seepage of an evanescent wave.

  Furthermore, according to the plasma CVD apparatus, the first gas and the second gas are converted into plasma by the evanescent wave that is a seepage wave of electromagnetic waves. Therefore, plasma can be generated uniformly in the vicinity of the incident surface of the processing container. Therefore, an oxide film can be uniformly formed on the object to be processed.

  In addition, according to the plasma CVD apparatus, a region having high plasma energy can be localized in the vicinity of the region where the evanescent wave has exuded. Therefore, the sheath electric field in the vicinity of the object to be processed can be reduced by setting the object to be processed at a position away from the incident surface. That is, since the energy of ions incident on the object to be processed can be reduced, ion damage given to the object to be processed and the insulating film formed on the object to be processed can be suppressed.

  An insulating film forming method according to a second aspect of the present invention includes an electromagnetic wave source that generates an electromagnetic wave, an incident surface on which an evanescent wave that is a seepage wave of the electromagnetic wave is incident, and an object to be processed is disposed therein An oxide film for forming an oxide film on the object to be processed is formed using a plasma CVD apparatus including a processing container capable of generating a plasma source that generates plasma by causing an evanescent wave to enter the processing container. A forming method, the step of disposing the object to be processed inside the processing container such that the distance from the incident surface is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, and a rare gas and an oxygen gas The first gas containing at least one of the above is introduced into the processing container from a position where the distance from the incident surface is less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source. Both the second gas containing at least one of the organosilicon compound and the organometallic compound is moved from the position where the distance from the incident surface is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source. And introducing the evanescent wave into the processing container from the incident surface, thereby causing plasma generated by the first gas and the second gas to enter the processing container. And depositing an oxide on the object to be processed.

  According to the method for forming an insulating film, since a gas containing at least one of an organosilicon compound and an organometallic compound is used as the second gas, a source gas having a relatively low molecular weight such as silane gas is used. Compared with the case, an oxide film with better coverage can be formed.

  In addition, according to the method for forming the insulating film, the first gas containing at least one of a rare gas and an oxygen gas is used as an electromagnetic wave generated by the electromagnetic wave source at a distance from the incident surface on which the evanescent wave is incident. It introduce | transduces into the inside of a processing container from the position used as less than this wavelength. That is, the first gas is introduced into the processing vessel from a region where electrons are accelerated by an electric field generated by an evanescent wave or in the vicinity thereof. Therefore, oxygen radicals can be efficiently generated in the processing container.

  Further, according to the method for forming the insulating film, the electromagnetic wave source generates a distance from the incident surface on which the evanescent wave is incident on the second gas containing at least one of the organosilicon compound and the organometallic compound. The first gas is separated from the position where the wavelength of the electromagnetic wave is greater than the wavelength of the electromagnetic wave and introduced into the processing container. That is, the second gas is introduced into the processing container from a region where an electric field generated by an evanescent wave is small. Therefore, it is possible to suppress the second gas from being excessively decomposed.

  Moreover, according to the method for forming the insulating film, it is possible to localize a region where the plasma energy is high near the region where the evanescent wave exudes. Accordingly, the sheath electric field in the vicinity of the object to be processed can be reduced by arranging the object to be processed at a position where the distance from the incident surface on which the vanescent wave is incident is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source. it can. Therefore, the energy of ions incident on the object to be processed can be reduced, so that ion damage given to the object to be processed and the insulating film formed on the object to be processed can be suppressed.

  Furthermore, according to the method for forming the insulating film, the first gas and the second gas are converted into plasma by an evanescent wave that is a seepage wave of electromagnetic waves. Therefore, plasma can be generated uniformly in the vicinity of the incident surface of the processing container. Therefore, an oxide film can be uniformly formed on the object to be processed.

  According to the present invention, a plasma CVD apparatus capable of satisfactorily forming an insulating film on a target object while suppressing damage to the target object and the insulating film formed on the target object, and An oxide film forming method is obtained.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In the present embodiment, an embodiment of a plasma enhanced chemical vapor deposition (CVD) apparatus of the present invention will be described. In the present embodiment, an embodiment of the method for forming an oxide film of the present invention will be described.

  As shown in FIGS. 1 and 2, the plasma CVD apparatus 1 includes a vacuum vessel 10 as a processing vessel, a plasma source antenna 20, a waveguide 30, a high-frequency power source 40 as an electromagnetic wave source, and a first gas introduction system. An upper gas introduction system 50, a lower gas introduction system 60 as a second gas introduction system, a gas discharge system 70, and the like are provided.

  The vacuum vessel 10 has an upper wall 11a, a bottom wall 11b as outer walls, and a peripheral wall 11c connecting the peripheral edge of the upper wall 11a and the peripheral edge of the bottom wall 11b, and the inside is decompressed to a vacuum state or the vicinity thereof. It is formed with the strength that can be done. As a material for forming the upper wall 11a, the bottom wall 11b, and the peripheral wall 11c, for example, a metal material such as aluminum can be used.

  The upper wall 11 a has an opening 13. The plasma source antenna 20 is fitted into the opening 13. Although not shown, the vacuum container 10 has a sealing mechanism that seals between the upper wall 11a and the plasma source antenna 20. With this sealing mechanism, the inner surface defining the opening 13 and the plasma source antenna 20 are hermetically sealed.

  As shown in FIGS. 1 and 2, the plasma source antenna 20 includes an upper plate 22a, a lower plate 22b, and a peripheral plate 22c that connects the three sides of the upper plate 22a and the three sides of the lower plate 22b. It is formed in a flat box shape with one peripheral part opened. As a material for forming the upper plate 22a, the lower plate 22b, and the peripheral plate 22c, for example, a metal material such as aluminum can be used.

  A region surrounded by the upper plate 22 a, the lower plate 22 b, and the peripheral plate 22 c is filled with a dielectric member (for example, synthetic quartz) 23. Therefore, the dielectric member 23 becomes a waveguide. The lower plate 22 b is a perforated plate having a plurality of holes 21. One open peripheral portion communicates with the high-frequency power source 40 through the waveguide 30.

  Each of the plurality of holes 21 is set to a size that causes a cutoff in the electromagnetic wave generated by the high frequency power supply 40. Therefore, these holes 21 may be less than half the wavelength of the electromagnetic wave generated by the high frequency power supply 40. However, since the state of attenuation of the evanescent wave is related to the diameter of the hole 21, it is excited by the evanescent wave. In order to effectively localize the plasma, it is preferable to set the hole diameter to a small diameter, for example, a diameter of about 2 mm.

  In Japan, 2.45 GHz, 5.8 GHz and 22.125 GHz electromagnetic wave sources (high frequency power supplies) are the maximum allowable value as a special example of the allowable value of electric field strength due to fundamental wave or spurious emission because of the use of electromagnetic waves for industrial purposes. (Radio equipment regulations Article 65 and Ministry of Posts and Telecommunications Notification No. 257). Therefore, it is easy to use an electromagnetic wave source of 2.45 GHz, 5.8 GHz, and 22.125 GHz as the high frequency power source 40.

  In the plasma CVD apparatus 1 of the present embodiment, for example, a 2.45 GHz power supply is used as the high frequency power supply 40. An electromagnetic wave of 2.45 GHz is cut off with a hole having a diameter of about 60 mm or less. Therefore, in the plasma CVD apparatus 1 of this embodiment, the diameter of the hole 21 is set to 10 mm or less, that is, 2 mm in order to localize plasma more effectively.

  With such a configuration, an evanescent wave, which is a seepage wave of the electromagnetic wave generated by the high frequency power supply 40, seeps out of the hole 21 of the plasma source antenna 20 inside the vacuum vessel 10. Therefore, in the plasma CVD apparatus 1 having the above-described configuration, the lower surface (inner surface) of the lower plate 22b becomes the incident surface F on which the evanescent wave is incident. When the plasma is generated by the evanescent wave, the propagation wave in the plasma source antenna 20 and the absorption wave of the plasma in the vacuum vessel 10 can be separated, so that the influence of the plasma on the propagation wave mode can be suppressed. .

  Inside the vacuum vessel 10 is provided a substrate support 14 for supporting a rectangular target substrate 100 as a target object. In the present embodiment, the substrate to be processed 100 can be disposed at a position where the distance between the upper surface F3 of the substrate to be processed 100 and the incident surface F is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source. The position of the support base 14 is set.

  The upper gas introduction system 50 uses, for example, a first gas containing at least one of at least one of a rare gas and oxygen of helium, neon, argon, krypton, or xenon in the vacuum vessel 10. It is for introduction inside. As shown in FIGS. 2 and 3, in the plasma CVD apparatus 1 of the present embodiment, the upper gas introduction system 50 includes, for example, an upper gas introduction pipe 51 as a first gas introduction part.

  The upper gas introduction pipe 51 is formed of a metal such as aluminum, stainless steel, or titanium, or a dielectric such as silicon oxide, aluminum oxide, or aluminum nitride. In consideration of the influence of the upper gas introduction pipe 51 on the electromagnetic field and plasma, the upper gas introduction pipe 51 is preferably formed of a dielectric material. However, considering the processing when forming the tube, it is cheaper and easier to form the upper gas introduction tube 51 from a metal material. Therefore, when the upper gas introduction pipe 51 is formed of a metal material, an insulating film may be formed on the outer surface of the upper gas introduction pipe 51.

  As shown in FIG. 3, the upper gas introduction pipe 51 has a plurality of piping parts 51a and one extending part 51b. The plurality of pipe portions 51a are piped in parallel with each other. Each of the piping parts 51a is provided with a plurality of gas outlets 52 downward at substantially equal intervals. Accordingly, the plurality of gas ejection ports 52 are located on substantially the same horizontal plane. In the present embodiment, the distance L1 between the imaginary plane F1 where the gas jet ports 52 are arranged and the incident surface F is set to be less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, for example, 10 mm. Yes.

  The extending part 51b is piped so as to be orthogonal to the plurality of pipe parts 51a, and the pipe parts 51a communicate with each other. Both ends of the extending portion 51 b extend through the peripheral wall 11 c of the vacuum vessel 10 and extend outward from the vacuum vessel 10. A first gas source cylinder (not shown) for supplying and storing the first gas can be detachably attached to both ends or one end of the extending portion 51b.

  The lower gas introduction system 60 is, for example, for introducing a second gas containing a source gas composed of at least one of an organic silicon compound and an organometallic compound into the vacuum vessel 10. As shown in FIGS. 2 and 4, in the plasma CVD apparatus 1 of the present embodiment, the lower gas introduction system 60 has, for example, a lower gas introduction pipe 61 as a second gas introduction part.

  Similar to the upper gas introduction pipe 51, the lower gas introduction pipe 61 is formed of a metal such as aluminum, stainless steel, or titanium, or a dielectric such as silicon oxide, aluminum oxide, or aluminum nitride.

  Considering the influence on the electromagnetic field and plasma, the lower gas introduction tube 61 is preferably formed of a dielectric material. When the lower gas introduction pipe 61 is formed of a metal material, it is preferable to form an insulating film on the outer surface of the lower gas introduction pipe 61.

  As shown in FIG. 4, the lower gas introduction pipe 61 has an annular portion 61a and a pair of extending portions 61b. The annular portion 61 a is formed to be slightly larger than the outer periphery of the substrate 100 to be processed. A plurality of gas outlets 62 are provided in the annular portion 61a downward at substantially equal intervals. Therefore, the plurality of gas ejection ports 62 are located on substantially the same horizontal plane. In the present embodiment, the distance L2 between the virtual plane F2 where the gas jet ports 62 are disposed and the incident surface F is set to be equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, for example, 200 mm. ing.

  Each extending portion 61b communicates with the annular portion 61a. One end of each extending portion 61 b extends through the peripheral wall 11 c of the vacuum vessel 10 and extends outward from the vacuum vessel 10. A second gas source cylinder (not shown) for supplying and storing the second gas can be detachably attached to one end of at least one extending portion 61b.

  By the way, the organosilicon compound gas and the organometallic compound gas used as the second gas are easily liquefied because they have a higher boiling point than monosilane and the like. Therefore, when an organic silicon compound gas or an organometallic compound gas is used as the second gas, the lower gas introduction system 60 is set to an appropriate temperature in order to stably introduce the second gas into the vacuum vessel 10. That is, it is desirable to keep the temperature at 80 to 200 ° C. Therefore, in the plasma CVD apparatus 1 of the present embodiment, the heating means 80 is provided in the lower gas introduction system 60. The heating means 80 has a heater, for example.

  A heater can be provided in the outer periphery of each extension part 61b. In this way, heat can be transmitted to the entire lower gas introduction system 60 by heat conduction of the material constituting the lower gas introduction pipe 61. Moreover, by doing in this way, compared with the case where the heating means 80 is installed in the vacuum vessel 10, the lower gas introduction system 60 can be maintained at an appropriate temperature with a simple configuration. In the case where the lower gas introduction pipe 61 is configured to transmit heat to the entire lower gas introduction system 60 by heat conduction of the material constituting the lower gas introduction pipe 61 as in this embodiment, the lower gas introduction pipe 61 is made of aluminum nitride. As described above, it is desirable to use a material having a large thermal conductivity coefficient.

  As shown in FIG. 2, the gas exhaust system 70 includes a gas exhaust unit 71 provided in the vacuum container 10 so as to communicate with the inside of the vacuum container 10, a vacuum exhaust system 72, and the like. As the vacuum exhaust system 72, for example, a turbo molecular pump can be used. By operating the evacuation system 72, the gas inside the vacuum vessel 10 can be discharged outside until a predetermined degree of vacuum is reached.

  Next, an example of a method for forming an oxide film using the plasma CVD apparatus 1 described above will be described. In the present embodiment, oxygen gas is used as the first gas, and tetraethoxysilane, which is a kind of tetraalkoxysilane, is used as the second gas, and an oxide film that forms the insulating film 101 on the substrate to be processed 100 is used. A forming method will be described.

  First, the substrate 100 to be processed is placed on the substrate support 14, the gas exhaust system 70 is operated, and the inside of the vacuum vessel 10 is substantially evacuated. Oxygen gas is supplied from the upper gas introduction system 50 into the vacuum container 10 at a flow rate of 400 SCCM so that the gas pressure inside the vacuum container 10 becomes 80 Pa, and from the lower gas introduction system 60 to the inside of the vacuum container 10. Tetraethoxysilane gas is supplied at a flow rate of 12 SCCM. At this time, the lower gas introduction system 60 is kept at an appropriate temperature (about 80 ° C. to 200 ° C.) by the heating means 80.

  The high frequency power supply 40 is turned on. As a result, the 2.45 GHz electromagnetic wave is guided to the plasma source 20 through the waveguide 30. The electromagnetic wave guided to the plasma source 20 oozes out from the hole 21 into the vacuum vessel 10 as an evanescent wave. The first and second gases are excited by the evanescent wave, and plasma is uniformly generated in the vicinity of the incident surface F. The first gas is introduced into the vacuum vessel 10 from a position where the distance L1 to the incident surface F is less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, for example, 10 mm. Molecules are excited and oxygen radicals are efficiently generated.

  On the other hand, the tetraethoxysilane gas that is the second gas is introduced into the vacuum chamber 10 from a position where the distance L2 from the incident surface F is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, for example, 200 mm. The evanescent wave hardly reaches the region where the tetraethoxysilane gas is introduced into the vacuum vessel 10. Therefore, excessive decomposition of tetraethoxysilane by the evanescent wave is suppressed. Further, even when the distance L2 from the incident surface F is 200 mm, oxygen radicals reach as a diffusion flow, so that tetraethoxysilane and oxygen radicals react efficiently, and the decomposition of tetraethoxysilane is promoted. The Accordingly, silicon oxide is deposited on the substrate to be processed 100 (the surface of the substrate to be processed 100).

  Since tetraethoxysilane is a compound having a larger molecular volume than monosilane or the like, it migrates on the surface of the substrate to be processed 100 due to its steric effect and adheres relatively uniformly to the surface of the substrate to be processed 100. Therefore, an insulating film (silicon oxide film) 101 with good film quality is formed on the substrate 100 to be processed.

  As described above, according to the plasma CVD apparatus of the present embodiment, a gas containing at least one of an organic silicon compound and an organometallic compound is used as the second gas. Compared to the case where a source gas having a relatively low molecular weight such as silane gas is used, the oxide film 101 having better coverage can be formed.

  Moreover, according to the plasma CVD apparatus 1, the first gas and the second gas are separated and introduced into the vacuum vessel 10. Specifically, the upper gas introduction pipe 51 for introducing the first gas is provided closer to the incident surface F than the lower gas introduction pipe 61 for introducing the second gas. More specifically, the upper gas introduction pipe 51 is provided at a position where the distance L1 between the upper surface and the incident surface F is less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, and the lower gas introduction pipe 61 is The distance L2 from the incident surface F is provided at a position where the distance is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source.

  Therefore, the first gas can be introduced into the vacuum vessel 10 from the region where the electrons are accelerated by the electric field generated by the evanescent wave or in the vicinity thereof, and oxygen radicals can be efficiently generated inside the vacuum vessel 10. Moreover, excessive decomposition | disassembly of 2nd gas can be suppressed by introduce | transducing 2nd gas into the inside of the vacuum vessel 10 from the area | region where there is little seepage of an evanescent wave.

  Furthermore, according to the plasma CVD apparatus 1 of the present embodiment, the first gas and the second gas are converted into plasma by an evanescent wave that is a seepage wave of electromagnetic waves. Therefore, plasma can be generated uniformly in the vicinity of the incident surface F. Therefore, the oxide film 101 can be uniformly formed on the substrate 100 to be processed.

  Moreover, according to the plasma CVD apparatus 1 of the present embodiment, a region where the plasma energy is high can be localized in the vicinity of the region where the evanescent wave exudes. Therefore, by setting the substrate to be processed 100 away from the incident surface F, the sheath electric field in the vicinity of the substrate to be processed 100 can be reduced. That is, since the energy of ions incident on the substrate to be processed 100 can be reduced, ion damage given to the substrate to be processed 100 and the insulating film 101 formed on the substrate to be processed 100 can be suppressed.

  In addition, according to the method for forming an insulating film of this embodiment, a gas containing at least one of an organic silicon compound and an organometallic compound is used as the second gas. Thus, the oxide film 101 with better coverage can be formed as compared with the case where a source gas having a relatively low molecular weight is used.

  Moreover, according to the method for forming an insulating film of the present embodiment, the electromagnetic wave source generates the first gas containing at least one of the rare gas and the oxygen gas from the incident surface on which the evanescent wave is incident. The inside of the vacuum vessel 10 is introduced from a position that is less than the wavelength of the electromagnetic wave. Therefore, oxygen radicals can be efficiently generated in the vacuum vessel 10.

  Furthermore, according to the method for forming an insulating film of the present embodiment, the second gas containing at least one of the organic silicon compound and the organometallic compound is separated from the incident surface on which the evanescent wave is incident by the electromagnetic wave source. Is separated from the first gas and introduced into the vacuum vessel 10 from a position where the wavelength of the electromagnetic wave generated by is increased. That is, the second gas is introduced into the vacuum vessel 10 from a region where the electric field generated by the evanescent wave is small. Therefore, it is possible to suppress the second gas from being excessively decomposed.

  Moreover, according to the method for forming an insulating film of the present embodiment, a region having high plasma energy can be localized in the vicinity of a region where the evanescent wave is exuding. Therefore, by disposing the substrate to be processed 100 at a position where the distance L3 from the incident surface F on which the vanescent wave is incident is greater than or equal to the wavelength of the electromagnetic wave generated by the electromagnetic wave source, the sheath electric field in the vicinity of the substrate to be processed 100 is generated. Can be small. Therefore, since the energy of ions incident on the substrate to be processed 100 can be reduced, ion damage given to the substrate to be processed 100 and the insulating film 101 formed on the substrate to be processed 100 can be suppressed.

  Further, in the case of performing plasma treatment such as forming the insulating film 101 on the substrate 100 to be processed as in the oxide film formation method of this embodiment, the first gas is at least one of a rare gas and an oxygen gas. Gas containing one side is adopted. As the first gas, oxygen and at least one rare gas and mixed gas of helium, neon, argon, krypton, and xenon can be used. Helium, neon, argon, krypton, and xenon can be added to oxygen at a wide addition ratio from 10% to 99%, and the formation rate of the insulating film can be increased by the addition ratio.

  In addition, most of organic silicon compounds and organometallic compounds contain oxygen in the constituent elements. Therefore, the first gas does not necessarily include oxygen gas, and by containing at least one kind of rare gas of helium, neon, argon, krypton, or xenon, By generating oxygen radicals, the insulating film 101 can be formed on the substrate 100 to be processed.

  However, as the first gas, it is more preferable to use a gas containing at least one rare gas of helium, neon, argon, krypton, or xenon and oxygen gas. By doing so, it is possible to generate a large amount of oxygen radicals in the vacuum chamber 10 and form the insulating film 101 with few oxygen vacancies on the substrate 100 to be processed.

  In order to generate oxygen radicals in the vacuum vessel 10 more efficiently, it is desirable to supply a first gas containing oxygen gas in the vicinity of the incident surface.

  Further, when the first gas contains oxygen gas, the flow rate when supplying the oxygen gas into the vacuum vessel 10 is larger than the flow rate when supplying the second gas into the vacuum vessel 10. It is preferable to set so that By doing in this way, oxygen radicals can exist more than the second gas below the position where the second gas is introduced. Therefore, since the oxidation of silicon atoms in the organic silicon compound and metal atoms in the organometallic oxide is promoted, the high-quality oxide film 101 with fewer oxygen vacancies can be formed.

  The second gas has a relatively large molecular weight, such as an organic silicon compound or an organic metal oxide, rather than using a gas containing a compound having a relatively small molecular weight, such as monosilane, and migrates on the substrate to be processed. It is preferable to employ a gas containing a compound that is easily generated. Thus, the insulating film 101 can be formed more uniformly on the substrate 100 to be processed.

  As the second gas, for example, tetraalkoxysilane, vinylalkoxysilane, alkyltrialkoxysilane, phenyltrialkoxysilane, polymethyldisiloxane, polymethylcyclotetrasiloxane, and the like can be used. Furthermore, as the second gas, for example, trimethylaluminum, triethylaluminum, tetrapropoxyzirconium, pentaethoxytantalum, tetrapropoxyhafnium, or the like can be used. By selecting trimethylaluminum or triethylaluminum, an aluminum oxide film can be formed on the substrate 100 to be processed. By selecting tetrapropoxyzirconium, a zirconium oxide film can be formed on the substrate 100 to be processed. By selecting pentaethoxytantalum, a tantalum oxide film can be formed on the substrate 100 to be processed. By selecting tetrapropoxy hafnium, a hafnium oxide film can be formed on the substrate to be processed. Further, hafnium oxide and zirconium oxide have a dielectric constant higher than that of silicon oxide. Therefore, by selecting tetrapropoxy hafnium or tetrapropoxy zirconium, the insulating film 101 having better insulating properties than the silicon oxide film can be formed.

  Hereinafter, a second embodiment of the present invention will be described with reference to FIGS. In this embodiment, another embodiment of the plasma CVD apparatus of the present invention will be described.

  The plasma CVD apparatus 1 of this embodiment is different from the plasma CVD apparatus 1 described in the first embodiment in the lower gas introduction system 60 and the heating means 80. Since the other configuration is the same as that of the plasma CVD apparatus 1 of the first embodiment described above, the overlapping description will be omitted by attaching the same reference numerals to the drawings.

  The lower gas introduction system 60 is formed of a metal such as aluminum, stainless steel, or titanium, or a dielectric such as silicon oxide, aluminum oxide, or aluminum nitride. Note that it is desirable to use a dielectric as the material of the lower gas introduction system 60, as in the plasma CVD apparatus 1 of the first embodiment.

  As shown in FIGS. 5 and 6, the lower gas introduction system 60 has a shower plate 63 as a second gas introduction part (lower gas introduction part). The shower plate 63 has a pair of plate members 63a and 63b facing each other and is formed in a flat box shape, and the second gas is circulated into the internal space S. The shower plate 63 has a planar shape and is larger than the substrate to be processed 100 that divides the vacuum vessel 10 into an upper chamber and a lower chamber, and covers the substrate support 4 from above. Further, it is fixed to the peripheral wall 11 c of the vacuum vessel 10. An extension portion on one end side of the shower plate 63 is opened to the outside of the vacuum vessel 10 through an opening 65 provided in the peripheral wall 11 c of the vacuum vessel 10. A second gas source cylinder (not shown) for supplying and storing the second gas can be detachably attached to the extending portion extending from the shower plate 63.

  The shower plate 63 is provided with a plurality of through portions 66 for allowing the second gas and oxygen radicals to flow between the upper and lower sides of the shower plate 63 in the upper and lower rooms. Further, the shower plate 63 is provided with a number of gas outlets 67 on the wall of the lower plate 63b.

  Further, the shower plate 63 is provided with heating means 68 having a high-temperature medium circulator 69. The high-temperature medium circulator 69 includes a pump 69a, a circulation path 69b, a heater (not shown), a high-temperature fluid (not shown), and the like. Examples of the high-temperature fluid include air, gases such as nitrogen, argon, krypton, and xenon, or water, ethylene glycol, mineral oil, alkylbenzene, diarylalkane, triaryldialkane, diphenyl-diphenylether mixture, alkylbiphenyl, and alkyl. It can be selected from liquids such as naphthalene.

  A circulation path 69 b for circulating a high-temperature fluid (a high-temperature gas or a high-temperature liquid) is provided inside the shower plate 63. The circulation path 69b is isolated from the internal space S through which the second gas flows. In this high-temperature medium circulator 69, the lower gas introduction system 60 is heated to 80 ° C. to 200 ° C. by heating the fluid with a heater and operating the pump 69a to circulate the heated high-temperature fluid inside the shower plate 63. It is configured to keep the temperature at a certain level.

  Thus, when the lower gas introduction system 60 is heated by circulation of a high-temperature medium, thermal energy is quickly transmitted to the lower gas introduction system 60 and the lower gas introduction system 60 can be heated evenly. For this reason, it is suitable for plasma processing in which an insulating film is formed using a gas containing an organosilicon compound gas or an organometallic compound gas, and fluctuations in the gas supply amount due to liquefaction of the organosilicon compound gas or the organometallic compound gas are achieved. Can be deterred. Therefore, when the insulating film 101 is formed over the substrate to be processed 100, good film thickness controllability and film thickness uniformity can be realized.

  As described above, if the plasma CVD apparatus 1 of the present embodiment is used, fluctuations in the gas supply amount due to liquefaction of the organosilicon compound gas or the organometallic compound gas can be suppressed. Therefore, the plasma CVD apparatus 1 of the present embodiment is suitable for plasma processing using a gas that is relatively easy to liquefy, such as an organic silicon compound gas or an organometallic compound gas.

A plasma CVD apparatus according to the third embodiment of the present invention will be described below with reference to FIG.
In the plasma CVD apparatus 1 of this embodiment, the plasma source 20 is different from that of the plasma CVD apparatus 1 described in the first embodiment. Since other configurations are the same as those of the first embodiment described above, overlapping descriptions are omitted by attaching the same reference numerals to the drawings.

  The plasma source 20 includes one or more, for example, five waveguides 25. These waveguides 25 are arranged side by side so that their longitudinal directions are parallel to each other. The number of waveguides 25 is arbitrary. Further, the waveguides 25 adjacent to each other may be in contact with each other, or may be provided at a desired interval.

  The lower wall of each waveguide 25 is a perforated plate having a plurality of holes 21. The plurality of holes 21 are provided on the lower wall of each waveguide 25 in a state of being arranged in one or more rows, for example, two rows. The diameter of the hole 21 may be less than half the wavelength of the electromagnetic wave generated by the high-frequency power source 40. To effectively localize the plasma excited by the evanescent wave, the hole diameter may be reduced. What is preferable is the same as in the first embodiment. In the present embodiment, the diameter of each hole 21 is set to about 2 mm. Although not shown, the inside of the waveguide 25 is filled with a dielectric member (for example, synthetic quartz). Therefore, this dielectric member becomes a waveguide as in the first embodiment.

  The upper wall 11 a has five elongated openings 13 so as to correspond to the number of the waveguides 25. Each waveguide 25 is fitted in each opening 13. Although not shown, the vacuum container 10 has a sealing mechanism that seals between the upper wall 11a and the waveguide 25. By this sealing mechanism, the space between the inner surface defining each opening 13 and each waveguide 25 is hermetically sealed.

  One end of each waveguide 25 is communicated with the high frequency power supply 40 via the waveguide 30 having a function as a power distributor. As a result, the electromagnetic waves generated by the high frequency power supply 40 are guided to the respective waveguides 25 through the waveguides 30. The electromagnetic wave guided to each waveguide 25 oozes out of each vacuum vessel 10 as an evanescent wave from each hole 21.

As in the plasma CVD apparatus of this embodiment, the plasma CVD apparatus 1 provided with the plasma source antenna 20 in which the waveguides 25 having a plurality of perforated plates are arranged side by side is provided for each plasma in order to make the plasma uniform. It is possible to change the ratio of power distribution to the waveguide 25, which is suitable when an insulating film is formed on a square substrate having a large area used for a large liquid crystal display device or the like.
The plasma CVD apparatus and the oxide film forming method of the present invention are not limited to the above-described embodiments, and can be implemented in various ways without departing from the gist thereof.

  In the first to third embodiments, the plasma source antenna including a perforated plate having a plurality of holes 21 set to a diameter less than ½ of the wavelength of the electromagnetic wave generated by the high-frequency power source 40 as the electromagnetic wave source. By providing 20, an evanescent wave is incident on the inside of the vacuum vessel 10, but the evanescent wave can be incident on the inside of the vacuum vessel 10 even by a difference in refractive index, for example. Further, the wave leaking through the hole 21 (evanescent wave) becomes a completely attenuated wave in free space. Therefore, if the thickness of the lower plate 22 b is sufficiently thin with respect to the diameter of the hole 21, the distance that the evanescent wave oozes out is proportional to the diameter of the hole 21. That is, in order to allow the evanescent wave to enter the vacuum vessel 10 with a desired intensity, the diameter of the hole 21 or the inside of the plasma source antenna 20 (the dielectric member filling the inside of the plasma source antenna 20). 23) and the difference in refractive index between the inside of the vacuum vessel 10 (the gas introduced into the inside of the vacuum vessel 10) may be set to a predetermined value.

  Furthermore, as a to-be-processed object, substrates, such as a glass substrate, a quartz glass substrate, a ceramic substrate, a resin substrate, or a silicon wafer, can be used, for example. As the object to be processed, a semiconductor layer such as single crystal silicon, polycrystalline silicon, microcrystalline silicon, or amorphous silicon formed by laser crystallization or solid phase crystallization is formed on the substrate as described above. You may use what was done. Further, as the object to be processed, the semiconductor layer and the insulating film are stacked in any order on the substrate as described above, or the semiconductor layer and the insulating film are stacked in any order on the substrate as described above. Alternatively, a circuit element having a portion or a part of the circuit element may be used.

1 is a top view showing a plasma CVD apparatus according to a first embodiment of the present invention. Sectional drawing of the plasma CVD apparatus shown in FIG. Sectional drawing of the apparatus which shows the upper gas introduction system (1st gas introduction system) of the plasma CVD apparatus shown in FIG. FIG. 2 is a schematic cross-sectional view of an apparatus showing a lower gas introduction system (second gas introduction system) of the plasma CVD apparatus shown in FIG. 1. Sectional drawing which shows the plasma CVD apparatus which concerns on the 2nd Embodiment of this invention. FIG. 6 is a schematic cross-sectional view of an apparatus showing a lower gas introduction system (second gas introduction system) of the plasma CVD apparatus shown in FIG. 5. The top view which shows roughly the plasma CVD apparatus concerning the 3rd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Plasma CVD apparatus, 10 ... Vacuum container (processing container), 20 ... Plasma source, 21 ... Hole, 50 ... Upper gas introduction system (first gas introduction system), 51 ... Upper gas introduction pipe (first gas) Introduction part), 60 ... lower gas introduction system (second gas introduction system), 61 ... lower gas introduction pipe (second gas introduction part), 63 ... shower plate (second gas introduction part), 100 ... covered Processing substrate (object to be processed), 101 ... oxide film

Claims (8)

An electromagnetic wave source that generates electromagnetic waves;
A treatment container having an incident surface on which an evanescent wave, which is a seeping wave of electromagnetic waves, is incident;
A plasma source for generating plasma by injecting an evanescent wave into the processing vessel;
A first gas introduction system having a first gas introduction part provided in the processing container and introducing a first gas containing at least one of a rare gas and an oxygen gas into the processing container;
A second gas introduction unit provided in the processing container and configured to separate a second gas containing at least one of an organic silicon compound and an organometallic compound from the first gas and introduce the second gas into the processing container; A second gas introduction system having
A plasma CVD apparatus, wherein the first and second gases are converted into plasma by an evanescent wave to form an insulating film on the object to be processed.   2. The plasma CVD according to claim 1, wherein the plasma source includes a perforated plate having a plurality of holes set to a diameter less than ½ of a wavelength of an electromagnetic wave generated by the electromagnetic wave source. apparatus.   The plasma CVD apparatus according to claim 2, wherein the plasma source includes at least one waveguide having the perforated plate. The plasma source includes a plurality of waveguides having the perforated plate,
3. The plasma CVD apparatus according to claim 2, wherein the plasma CVD apparatus includes at least one power distributor that distributes power to the plurality of waveguides and is arranged so that the longitudinal directions thereof are parallel to each other. .   The said processing container is formed so that the said to-be-processed object can be arrange | positioned in the position where the distance with the said incident surface becomes more than the wavelength of the electromagnetic waves generated by the said electromagnetic wave source. The plasma CVD apparatus according to any one of the above.   6. The plasma CVD apparatus according to claim 1, wherein the first gas introduction part is provided closer to the incident surface than the second gas introduction part.   The distance between the first gas introduction part and the incident surface is set to be less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source, and the second gas introduction part is connected to the incident surface. The plasma CVD apparatus according to claim 6, wherein a distance therebetween is set to be equal to or greater than a wavelength of an electromagnetic wave generated by the electromagnetic wave source. An electromagnetic wave source that generates an electromagnetic wave, a processing container having an incident surface on which an evanescent wave that is a seepage wave of the electromagnetic wave is incident, and an object to be processed can be disposed therein, and the evanescent wave is incident on the inside of the processing container An oxide film forming method for forming an oxide film on the object to be processed using a plasma CVD apparatus including a plasma source that generates plasma.
Placing the object to be processed inside the processing container so that the distance from the incident surface is equal to or greater than the wavelength of the electromagnetic wave generated by the electromagnetic wave source;
A first gas containing at least one of a rare gas and an oxygen gas is introduced into the processing container from a position where the distance from the incident surface is less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source; A second gas containing at least one of an organosilicon compound and an organometallic compound is separated from the first gas from a position where the distance from the incident surface is not less than the wavelength of the electromagnetic wave generated by the electromagnetic wave source. And introducing into the processing container;
By making an evanescent wave incident on the inside of the processing container from the incident surface, plasma is generated by the first gas and the second gas inside the processing container, and oxide is deposited on the object to be processed. And a step of forming an oxide film.

Images