JP2006012962A - Microwave plasma processing apparatus using vacuum ultraviolet light shielding plate with oblique through hole and its processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing apparatus that suppresses irradiation of an ultraviolet light to a substrate 502 to be processed, reduces a damage due to the irradiation of the vacuum ultraviolet light or surface abnormal dispersion, and realizes high-speed and high quality processing. <P>SOLUTION: The plasma processing apparatus is comprised of: a plasma processing chamber wherein a part of partition is formed of a plane microwave transmission window; a means for supporting a substrate to be processed that is arranged in the plasma processing chamber; a means for introducing a process gas into the plasma processing chamber; an exhausting means for evacuating the plasma processing chamber; and a plane microwave introduction means with a plurality of slots for introducing microwaves to the plasma processing chamber through the microwave transmission window. In this case, a plane light shielding plate having a plurality of oblique through holes and made of a material difficult to be transmitted by a vacuum ultraviolet light is provided between the microwave transmission window and the substrate supporting means, so that the microwave transmission window is not seen from the surface of the substrate through the through holes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a microwave plasma processing apparatus. More specifically, the present invention relates to a microwave plasma processing apparatus capable of suppressing substrate irradiation with vacuum ultraviolet light, which is harmful to the process, and capable of high quality processing.

  As a plasma processing apparatus that uses microwaves as an excitation source for generating plasma, a CVD apparatus, an etching apparatus, an ashing apparatus, a surface modification apparatus, and the like are known.

  The substrate to be processed using such a so-called microwave plasma processing apparatus is processed as follows. That is, a processing gas is introduced into a processing chamber of a microwave plasma processing apparatus, and microwave energy is supplied from the microwave supply apparatus provided outside the processing chamber through the microwave transmission window to the processing chamber to generate plasma. Is generated, gas is excited, dissociated, and reacted to treat the surface of the substrate disposed in the processing chamber.

  In microwave plasma processing equipment, microwaves are used as the gas excitation source, so electrons can be accelerated to relatively low energy with high frequency electric fields, and gas molecules can be efficiently ionized and excited. Can be made. Therefore, when microwave plasma processing equipment is used, high ionization efficiency, excitation efficiency and decomposition efficiency of gas, high-density processing at low temperature and high speed, which can form plasma with high density and low electron temperature relatively easily It has the advantage that it can. In addition, since the microwave has a property of transmitting through the dielectric, the plasma processing apparatus can be configured as an electrodeless discharge type, and therefore, there is an advantage that highly clean plasma processing can be performed.

  In order to further increase the speed of such a microwave plasma processing apparatus, a plasma processing apparatus using electron cyclotron resonance (ECR) has been put into practical use. In the ECR, when the magnetic flux density is 87.5 mT, the electron cyclotron frequency at which the electrons rotate around the magnetic field lines matches the general microwave frequency of 2.45 GHz, and the electrons absorb the microwaves resonantly. This is a phenomenon in which high-density plasma is generated by acceleration. In such an ECR plasma processing apparatus, the following four configurations are known as typical configurations of the microwave introduction unit and the magnetic field generation unit.

  That is, (i) a microwave propagating through a waveguide is introduced from a facing surface of a substrate to be processed into a cylindrical plasma generation chamber through a transmission window, and a divergent magnetic field coaxial with the central axis of the plasma generation chamber Is introduced through an electromagnetic coil provided around the plasma generation chamber; (ii) microwaves transmitted through the waveguide are introduced into the bell-shaped plasma generation chamber from the opposite surface of the substrate to be processed. A configuration in which a magnetic field coaxial with the central axis of the plasma generation chamber is introduced through an electromagnetic coil provided around the plasma generation chamber; (iii) microwaves are transmitted through a Rigitano coil, which is a type of cylindrical slot antenna. A configuration in which a magnetic field coaxial with the central axis of the plasma generation chamber is introduced from the periphery through a magnetic coil provided around the plasma generation chamber (Rigitano method); (iv) via a waveguide The microwave transmitted from the opposite surface of the substrate to be processed is introduced into the cylindrical plasma generation chamber via the flat slot antenna, and a loop magnetic field parallel to the antenna plane is provided on the back surface of the planar antenna. It is the structure (planar slot antenna system) introduced through a magnet.

  As an example of a microwave plasma processing apparatus, in recent years, an apparatus using an endless annular waveguide in which a plurality of slots are formed on the H plane has been proposed as a uniform and efficient introduction apparatus for microwaves (Patent No. 1). No. 2,886,752 and Japanese Patent No. 2,925,535). FIG. 5A shows this microwave plasma processing apparatus, and FIG. 5B shows the plasma generation mechanism. 501 is a plasma processing chamber, 502 is a substrate to be processed, 503 is a support for the substrate 502, 504 is a substrate temperature adjusting means, 505 is a plasma processing gas introducing means provided around the plasma processing chamber 501, 506 is exhausted, Reference numeral 507 denotes a flat dielectric window that separates the plasma processing chamber 501 from the atmosphere side. Reference numeral 508 denotes a slotted endless annular waveguide for introducing microwaves into the plasma processing chamber 501 through the dielectric window 507. Is an inlet for introducing microwaves into the annular waveguide, 512 is an annular waveguide, 513 is a standing wave generated in the annular waveguide, 514 is a slot, 515 is a surface wave propagating on the surface of the dielectric window 507, 516 Is a surface standing wave generated by surface waves from adjacent slots interfering with each other, 517 is a generating part plasma generated by the surface wave standing wave, and 518 is a diffusion of the generating part plasma. It is more generated plasma bulk.

The plasma treatment is performed as follows. The inside of the plasma processing chamber 501 is evacuated through an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 501 at a predetermined flow rate through a gas introduction means 505 provided around the plasma processing chamber 501. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the plasma processing chamber 501 at a predetermined pressure. A desired power is supplied from a microwave power source (not shown) into the plasma processing chamber 501 through the endless annular waveguide 508. At this time, the microwave introduced into the endless annular waveguide 508 is divided into two at the left and right at the E branch of the introduction port 511, interferes within the endless annular waveguide 512, and every 1/2 of the guide wavelength. This causes an “antinode” of the standing wave 513 in the tube. Plasma is generated by the microwave introduced through the dielectric window 507 through the slot 514 provided at the position where the surface current between the antinodes of the standing wave becomes maximum, and introduced into the plasma processing chamber 501. The plasma electron density is a cut-off density (7.5 × 10 ¹⁰ cm ^{−3 in} the case of microwaves having a frequency of 2.45 GHz), more specifically, the threshold density for generating a surface wave mode (in the case of using a quartz window, 3. If it exceeds 4 × 10 ¹¹ cm ⁻³ ), the microwave incident on the interface between the dielectric window 507 and the plasma cannot propagate into the plasma and propagates as a surface wave 515 on the surface of the dielectric window 507. The surface waves 515 introduced from adjacent slots interfere with each other, and a surface standing wave 516 having an antinode every ½ of the wavelength of the surface wave 515 is generated. Ultra high density plasma 517 is generated near the dielectric window 507 by the surface standing wave 516 localized near the surface of the dielectric window 507. The ultra high density plasma 517 is purely diffused and relaxed in the direction of the substrate to be processed 502, and a high density and low electron temperature plasma bulk 518 is generated in the vicinity of the substrate to be processed 502. The processing gas is excited by the generated high density plasma and processes the surface of the substrate to be processed 502 placed on the support 503.

By using such a microwave plasma processing apparatus, an electron density of 10 ¹² cm ⁻³ or more and an electron temperature of 3 eV or less with a microwave power of 1 kW or more and a uniformity within ± 3% in a large-diameter space having a diameter of about 300 mm. High density and low electron temperature plasma with a plasma potential of 20 V or less can be generated, so that the gas can be sufficiently reacted and supplied to the substrate in an active state, and the substrate surface damage due to incident ions is reduced, so that high quality and uniform even at low temperatures In addition, high-speed processing becomes possible.
Japanese Patent No. 2886752 Japanese Patent No. 2925535

  However, when processing the substrate to be processed 502 using the microwave plasma processing apparatus as described above, a strong vacuum is generated from the ultra-high density plasma 517 region generated by the surface standing wave 516 localized near the dielectric window 507. Ultraviolet light is generated and irradiated on the substrate to be processed 502, which may cause bonding defects and abnormal surface diffusion.

  The main object of the present invention is to solve the deficiencies in the conventional microwave plasma processing apparatus described above, and to suppress vacuum ultraviolet light irradiation to the substrate to be processed 502 to reduce vacuum ultraviolet light irradiation damage and surface abnormal diffusion. Another object of the present invention is to provide a plasma processing apparatus capable of high-quality processing at high speed.

  The present invention relates to a plasma processing chamber in which a part of a partition wall is constituted by a flat plate-shaped microwave transmission window, a substrate support means installed in the plasma processing chamber, and a processing gas introduction means into the plasma processing chamber And a flat plate microwave introducing means having a plurality of slots for introducing microwaves into the plasma processing chamber through the microwave transmission window. A processing apparatus, wherein a plurality of through holes are formed obliquely between the microwave transmitting window and the substrate supporting means so that the microwave transmitting window cannot be seen from the surface of the substrate through the through hole. A flat light-shielding plate made of a material that does not transmit ultraviolet light is provided.

  According to the present invention, it is possible to provide a plasma processing apparatus capable of suppressing vacuum ultraviolet light irradiation to a substrate to be processed to reduce vacuum ultraviolet light irradiation damage and surface abnormal diffusion, and capable of high-quality processing at high speed.

  The microwave plasma processing apparatus of this invention is demonstrated using FIG. 101 is a plasma processing chamber, 102 is a substrate to be processed, 103 is a support for the substrate 102, 104 is a substrate temperature adjusting means, 105 is a gas introduction means for plasma processing provided around the plasma processing chamber 101, 106 is exhausted, 107 is a dielectric window, 108 is a plate-like microwave supply means with slots for introducing microwaves into the plasma processing chamber 101 through the dielectric window 107, and 109 is a vacuum ultraviolet light shielding plate with oblique through holes. .

  The plasma treatment is performed as follows. The plasma processing chamber 101 is evacuated through an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 101 at a predetermined flow rate through a gas introduction means 105 provided around the plasma processing chamber 101. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the plasma processing chamber 101 at a predetermined pressure. A microwave having a desired power is introduced from a microwave power source (not shown) through the dielectric window 107 into the plasma processing chamber 101 through the slotted flat plate microwave supply means 108 to generate high-density plasma. The processing gas introduced from the periphery is activated by being excited, ionized, and reacted by the generated high-density plasma, and processes the surface of the substrate to be processed 102 placed on the support 103.

  At this time, strong vacuum ultraviolet light is generated from the high-density plasma generation region, but is absorbed by the vacuum ultraviolet light shielding plate 109 with oblique through holes, and thus does not reach the surface of the substrate to be processed 102, and damage due to irradiation with vacuum ultraviolet light. And abnormal surface diffusion can be suppressed.

  The wavelength of the vacuum ultraviolet light to be shielded by the microwave plasma processing apparatus of the present invention is a wavelength at which each layer in the substrate to be processed 102 can absorb and cause a bonding defect. For example, in the case of a silicon layer, all wavelengths of 200 nm or less are targeted, and in the case of a silicon oxide layer, wavelengths of 165 nm or less are targeted.

The material of the vacuum ultraviolet light shielding plate 109 with oblique through-holes used in the microwave plasma processing apparatus of the present invention can be applied as long as it can absorb the target vacuum ultraviolet light, for example, all vacuum ultraviolet of 200 nm or less. If light is a target, Si, Si ₃ N ₄ , carbon, etc. can be applied, and if vacuum ultraviolet light of 165 nm or less is a target, SiO ₂ , Al ₂ O ₃ , AlN, etc. are applicable.

  The shape of the through hole used in the microwave plasma processing apparatus of the present invention will be described with reference to FIG. The shape of the through hole can be applied as long as the surface of the dielectric window 107 is not visible from the surface of the substrate to be processed 102 through the through hole. As shown in FIG. 3, even if it can be seen with one light shielding plate 109, it may be made invisible with a two-stage structure.

  An example of a method for producing a vacuum ultraviolet light shielding plate with oblique holes used in the microwave plasma processing apparatus of the present invention will be described with reference to FIG. (A) is a perforated type, and perforates the vacuum ultraviolet light shielding disk obliquely. This is easy when the drilling angle is close to vertical, but when the drilling angle is close to parallel, the cutting tool and the light-shielding disk interfere spatially and become difficult. (B) is a tube bundle sintering type used when the perforation angle is nearly parallel. Bundling a number of tubes in a fan-shaped frame and sintering; 2. Diagonally cut from the center of the fan in the direction of the back. The resulting fan-shaped portion is fitted into a circular frame and re-sintered.

  The slotted flat plate microwave supply means 108 used in the microwave plasma processing apparatus of the present invention is a slotless endless annular waveguide or a coaxially introduced flat plate multi-slot antenna. Any device that can be supplied is applicable.

  The material of the slotted flat plate microwave supply means 108 used in the microwave plasma processing apparatus of the present invention can be any conductive material. However, in order to suppress the propagation loss of the microwave as much as possible, Al having high conductivity is used. SUS, Cu, Ag / Cu plated SUS, etc. are optimal.

  The microwave frequency used in the microwave plasma processing apparatus and the processing method of the present invention can be appropriately selected from the range of 0.8 GHz to 20 GHz.

  In the microwave plasma processing apparatus and processing method of the present invention, a magnetic field generating means may be used for processing at a lower pressure. As the magnetic field used in the plasma processing apparatus and the processing method of the present invention, any magnetic field perpendicular to the electric field generated in the slot width direction is applicable. As the magnetic field generating means, a permanent magnet can be used in addition to the coil. When using a coil, other cooling means such as a water cooling mechanism or air cooling may be used to prevent overheating.

  In the microwave plasma processing method of the present invention, the pressure in the plasma processing chamber is in the range of 0.1 mTorr to 10 Torr, and more preferably in the range of 5 mTorr to 5 Torr.

Formation of the deposited film by the microwave plasma processing method of the present invention is performed by appropriately selecting a gas to be used, and thereby Si ₃ N ₄ , SiO ₂ , SiOF, Ta ₂ O ₅ , TiO ₂ , TiN, Al ₂ O ₃ , AlN. Various deposited films such as insulating films such as MgF ₂ , semiconductor films such as a-Si, poly-Si, SiC, and GaAs, and metal films such as Al, W, Mo, Ti, and Ta can be efficiently formed. Is possible.

  The substrate to be processed 102 to be processed by the plasma processing method of the present invention may be a semiconductor, a conductive one, or an electrically insulating one.

  Examples of the conductive substrate include metals such as Fe, Ni, Cr, Al, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb, or alloys thereof, such as brass and stainless steel.

Examples of the insulating substrate include SiO ₂ -based quartz and various glasses, Si ₃ N ₄ , NaCl, KCl, LiF, CaF ₂ , BaF ₂ , Al ₂ O ₃ , AlN, MgO, and other inorganic materials, polyethylene, polyester, polycarbonate, Examples thereof include organic acetate films such as cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide, and windows.

  The direction of the gas introducing means 105 used in the plasma processing apparatus of the present invention is such that the gas is sufficiently supplied to the vicinity of the center after passing through the plasma region generated in the vicinity of the dielectric window 108 and then the substrate surface is moved from the center to the periphery. It is optimal to have a structure in which a gas can be blown toward the dielectric window 108 so as to flow.

  As a gas used when forming a thin film on a substrate by a CVD method, generally known gases can be used.

The source gas containing Si atoms introduced into the plasma processing chamber 101 via the processing gas introduction means 105 when forming a Si-based semiconductor thin film such as a-Si, poly-Si, or SiC is SiH ₄ , Si. Inorganic silanes such as ₂ H ₆ , organic silanes such as tetraethylsilane (TES), tetramethylsilane (TMS), dimethylsilane (DMS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), SiF ₄ , Si ₂ F ₆ , Si ₃ F ₈ , SiHF ₃ , SiH ₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl, SiCl ₂ F ₂ , etc. And those which are in a gas state at normal temperature and pressure or can be easily gasified. In this case, H ₂ , He, Ne, Ar, Kr, Xe, and Rn are listed as additive gas or carrier gas that may be introduced by mixing with Si source gas.

Examples of raw materials containing Si atoms introduced through the processing gas introduction means 105 when forming a Si compound-based thin film such as Si ₃ N ₄ or SiO ₂ include inorganic silanes such as SiH ₄ and Si ₂ H _6. , Organic silanes such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), octamethylcyclotetrasilane (OMCTS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), SiF ₄ , Si ₂ F ₆ , halogenated silanes such as Si ₃ F ₈ , SiHF ₃ , SiH ₂ F ₂ , SiCl ₄ , Si ₂ Cl ₆ , SiHCl ₃ , SiH ₂ Cl ₂ , SiH ₃ Cl, SiCl ₂ F _2, etc. And those which are in a gas state or can be easily gasified. In this case, the nitrogen source gas or the oxygen source gas introduced simultaneously includes N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS), O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO _{2 and the} like can be mentioned.

As raw materials containing metal atoms introduced through the processing gas introduction means 105 when forming a metal thin film such as Al, W, Mo, Ti, Ta, etc., trimethylaluminum (TMAl), triethylaluminum (TEAl), Organic metals such as triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa), triethylgallium (TEGa), Examples thereof include metal halides such as AlCl ₃ , WF ₆ , TiCl ₃ , and TaCl ₅ . In this case, H ₂ , He, Ne, Ar, Kr, Xe, and Rn are listed as additive gas or carrier gas that may be introduced by mixing with Si source gas.

As a raw material containing a metal atom introduced through the processing gas introduction means 105 in the case of forming a metal compound thin film such as Al ₂ O ₃ , AlN, Ta ₂ O ₅ , TiO ₂ , TiN, WO ₃ , trimethyl is used. Aluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), tungsten carbonyl (W (CO) ₆ ), molybdenum carbonyl (Mo (CO) ₆ ), trimethylgallium (TMGa) And organic metals such as triethylgallium (TEGa), and metal halides such as AlCl ₃ , WF ₆ , TiCl ₃ , and TaCl ₅ . Further, in this case, oxygen source gas or nitrogen source gas to be introduced at the same time includes O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , N ₂ , NH ₃ , N ₂ H ₄ , hexamethyl A disilazane (HMDS) etc. are mentioned.

The etching gas introduced from the processing gas inlet 105 when etching the substrate surface is F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₈ , CF _2. Cl ₂ , SF ₆ , NF ₃ , Cl ₂ , CCl ₄ , CH ₂ Cl ₂ , C ₂ Cl _{6 and the} like can be mentioned.

As ashing gas introduced from the processing gas inlet 105 when ashing and removing organic components on the substrate surface such as photoresist, O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , H ₂ etc. are mentioned.

  In addition, when the microwave plasma processing apparatus and the processing method of the present invention are applied to surface modification, for example, Si, Al, Ti, Zn, Ta or the like is used as a substrate or a surface layer by appropriately selecting a gas to be used. Then, oxidation treatment or nitridation treatment of these substrates or surface layers, doping treatment of B, As, P, etc. can be performed. Furthermore, the film forming technique employed in the present invention can also be applied to a cleaning method. In that case, it can also be used for cleaning oxides, organic substances, heavy metals, and the like.

Examples of the oxidizing gas introduced through the processing gas inlet 105 when the substrate is subjected to the oxidation surface treatment include O ₂ , O ₃ , H ₂ O, NO, N ₂ O, and NO ₂ . Further, examples of the nitriding gas introduced through the processing gas inlet 115 when the substrate is nitrided include N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS), and the like.

The cleaning / ashing gas introduced from the processing gas inlet 105 when the organic substance on the substrate surface is cleaned or when the organic component such as a photoresist on the substrate surface is removed by ashing is used as O ₂ , O ₃ , H _{2. O, NO, N 2 O,} NO 2, such as _{H 2} and the like. The cleaning gas introduced from the processing gas inlet 105 when cleaning the inorganic substance on the substrate surface includes F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , C ₄ F ₈ , and CF ₂ Cl. ₂ , SF ₆ , NF _{3 and the} like.

[Example of plasma processing equipment]
Hereinafter, the microwave plasma processing apparatus of the present invention will be described more specifically with examples of the apparatus, but the present invention is not limited to these apparatus examples.

(Device Example 1)
As an example of the microwave plasma processing apparatus of the present invention, an example using a quartz vacuum ultraviolet light shielding plate and a slotted endless annular waveguide will be described with reference to FIG. 301 is a cylindrical plasma processing chamber, 302 is a substrate to be processed, 303 is a support for the substrate 302, 304 is a substrate temperature adjusting means, 305 is a gas introduction means for plasma processing provided around the plasma processing chamber 301, 306 Is an exhaust, 307 is a dielectric window, 308 is a slotless endless annular waveguide for introducing microwaves into the plasma processing chamber 301 through the dielectric window 307, and 309 is a vacuum ultraviolet light shielding plate with an oblique hole. It is.

  The dielectric window 307 is made of anhydrous fused quartz and has a thickness of 16 mm.

  The slotted endless annular waveguide 308 is in TE10 mode, has an inner wall cross-sectional dimension of 27 mm × 96 mm (inner wavelength of 158.8 mm), and the center diameter of the waveguide is 151.6 mm (one circumference is three times the inner wavelength) ) Was used. The slotted endless annular waveguide 308 is made of Al alloy in order to suppress microwave propagation loss. A slot for introducing a microwave into the plasma processing chamber 301 is formed on the H surface of the slotted endless annular waveguide 308. The slot is a rectangle having a length of 40 mm and a width of 4 mm, and six slots are radially formed at intervals of 60 ° at a center diameter of 151.6 mm. The slotted endless annular waveguide 308 is connected in turn with a 4E tuner, a directional coupler, an isolator, and a microwave power source (not shown) having a frequency of 2.45 GHz.

  As a material of the vacuum ultraviolet light shielding plate 309 with oblique through holes, fused quartz (thickness 8 mm) was used in consideration of suppression of damage to the vacuum ultraviolet light generated in the gate oxide film. The oblique through-holes were formed in a radial shape with a hole diameter of 5 mm and a pitch of 10 mm, and radially with an angle of 30 ° with respect to the light shielding plate 309.

  The plasma treatment is performed as follows. The inside of the plasma processing chamber 301 is evacuated through an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 301 at a predetermined flow rate through a gas introduction unit 305 provided around the plasma processing chamber 301. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the plasma processing chamber 301 at a predetermined pressure. A desired power is supplied from a microwave power source (not shown) to the plasma processing chamber 301 through the dielectric window 307 through the slotted endless annular waveguide 308.

  At this time, high-density plasma is generated by the surface wave electric field generated in the vicinity of the dielectric window 307 and radiates vacuum ultraviolet light, but is absorbed by the vacuum ultraviolet light shielding plate 309 with oblique through holes, and is applied to the surface of the substrate 302 to be processed. Will not reach.

  The processing gas introduced from the periphery is activated by being excited, ionized and reacted by the generated high-density plasma, and the surface of the substrate 302 to be processed placed on the support 303 is processed at high speed and with high quality.

(Device example 2)
As another example of the microwave plasma processing apparatus of the present invention, an example in which a coaxially introduced multi-slot antenna and a silicon light shielding plate are used will be described with reference to FIG. 401 is a cylindrical plasma processing chamber, 402 is a substrate to be processed, 403 is a support for the substrate 402, 404 is a substrate temperature adjusting unit, 405 is a plasma processing gas introducing unit provided around the plasma processing chamber 401, and 406. 407 is a dielectric window, 408 is a coaxial multi-slot antenna for introducing microwaves into the plasma processing chamber 401 through the dielectric window 407, and 409 is a vacuum ultraviolet light shielding plate with oblique through holes made of silicon. It is.

  The dielectric window 407 is made of anhydrous fused quartz and has a thickness of 16 mm. The coaxial introduction slot antenna 408 includes a central axis for supplying microwave power and a large number of slots arranged on the antenna disk. The coaxial multi-slot antenna 408 is made of Cu for the central axis and Al for the antenna disk in order to suppress microwave propagation loss. As for the shape of the slot, a rectangular shape having a length of 12 mm and a width of 1 mm is formed innumerably in the tangential direction of the circle in a concentric shape with an interval of 12 mm. A 4E tuner, a directional coupler, an isolator, and a microwave power source (not shown) having a frequency of 2.45 GHz are sequentially connected to the coaxially introduced multi-slot antenna 408.

  As the material of the vacuum ultraviolet light shielding plate 209 with oblique through holes, silicon (thickness 8 mm) was used in consideration of suppression of vacuum ultraviolet light irradiation damage generated in the channel portion. The diagonal through-holes were formed with a diameter of 4 mm and a pitch of 12 mm, and 500 radial holes were formed at an angle of 30 ° with respect to the light shielding plate 209.

  The plasma treatment is performed as follows. The plasma processing chamber 401 is evacuated through an exhaust system (not shown). Subsequently, a processing gas is introduced into the plasma processing chamber 401 at a predetermined flow rate through a gas introduction means 405 provided around the plasma processing chamber 401. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the plasma processing chamber 401 at a predetermined pressure. A desired power is supplied from a microwave power source (not shown) into the plasma processing chamber 401 via the endless annular waveguide 408.

  At this time, high-density plasma is generated by the surface wave electric field generated in the vicinity of the dielectric window 407 and radiates vacuum ultraviolet light. However, the high-density plasma is absorbed by the vacuum ultraviolet light shielding plate 409 with oblique through holes and Will not reach.

  The processing gas introduced from the periphery is activated by being excited, ionized and reacted by the generated high-density plasma, and the surface of the substrate to be processed 402 placed on the support 403 is processed at high speed and with high quality.

  Hereinafter, the microwave plasma processing apparatus and the processing method of the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

  Using the microwave plasma processing apparatus shown in FIG. 3, the surface nitridation of the semiconductor element gate oxide film was performed.

As the substrate 302, a φ8 ″ P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) with a 1.4 nm oxide film was used. First, after the silicon substrate 302 was placed on the substrate support base 303, The inside of the plasma processing chamber 301 was evacuated through an exhaust system (not shown), and the pressure was reduced to a value of 10 ⁻⁷ Torr. Subsequently, the heater 304 was energized, and the silicon substrate 302 was heated to 300 ° C. At this temperature, nitrogen gas was introduced into the processing chamber 301 at a flow rate of 300 sccm through the plasma processing gas inlet 305. Next, a conductance valve (not shown) provided in the exhaust system (not shown). The inside of the processing chamber 301 was maintained at 0.1 Torr, and then 1.0 kW of power was supplied from a 2.45 GHz microwave power source (not shown) to the slotless end. In this way, plasma was generated in the plasma processing chamber 301. At this time, nitrogen gas introduced through the plasma processing gas inlet 305 was generated in the plasma processing chamber 301. Excited and decomposed to become active species such as N + ions and N radicals, transported in the direction of the silicon substrate 302, and nitrided the surface of the silicon oxide film to a depth of about 0.8 nm.

After the treatment, the film quality such as nitriding profile, breakdown voltage, and leakage current was evaluated. The peak depth of the nitriding profile was 0.3 nm, which was shallower by about 1/3 than when the vacuum ultraviolet light shielding plate 309 was not used (0.8 nm). The withstand voltage was 9.6 MV / cm, and the leakage current was 2.2 μA / cm ² , which was good.

  Using the microwave plasma processing apparatus shown in FIG. 4, a silicon oxide film for insulating a semiconductor element gate was formed by direct oxidation of a silicon substrate.

A φ8 ″ P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) was used as the substrate 402. First, the silicon substrate 402 was placed on the substrate support 403. An exhaust system (not shown) was used. Then, the inside of the plasma processing chamber 401 was evacuated and depressurized to a value of 10 ⁻⁷ Torr, and then the heater 404 was energized to heat the silicon substrate 402 to 450 ° C. and maintain the substrate at this temperature. Oxygen gas was introduced into the plasma processing chamber 401 through the plasma processing gas inlet 405 at a flow rate of 200 sccm, and then a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to provide the plasma processing chamber. The inside of 401 was kept at 50 mTorr, and then 1.0 kW of power was supplied from a 2.45 GHz microwave power source to the coaxially introduced multi-slot antenna 40. Was supplied into the plasma processing chamber 401. Thus, plasma was generated in the plasma processing chamber 401. Oxygen gas introduced through the plasma processing gas inlet 405 was excited in the plasma processing chamber 401. It was decomposed into active species and transported in the direction of the silicon substrate 402, and the surface of the silicon substrate 402 was oxidized by about 1.4 nm.

After the treatment, the withstand voltage, leakage current, and flat band shift were evaluated. The breakdown voltage was as good as 9.3 MV / cm, the leakage current was 3.1 μA / cm ² , and ΔVfb was 0.2 V.

  A microwave plasma processing apparatus shown in FIG. 4 was used to form a tantalum oxide film for semiconductor element gate insulation.

A φ8 ″ P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) was used as the substrate 402. First, the silicon substrate 402 was placed on the substrate support 403. An exhaust system (not shown) was used. Then, the inside of the plasma processing chamber 401 was evacuated and depressurized to a value of 10 ⁻⁷ Torr, and then the heater 404 was energized to heat the silicon substrate 402 to 300 ° C., and the substrate was maintained at this temperature. Through the plasma processing gas inlet 405, oxygen gas was introduced into the processing chamber 401 at a flow rate of 200 sccm and TEOT gas at a flow rate of 10 sccm, and then a conductance valve (not shown) provided in an exhaust system (not shown). (Not shown) was adjusted, and the inside of the plasma processing chamber 401 was maintained at 50 mTorr, and then 2.0 kW of power from a 2.45 GHz microwave power source. The plasma was supplied into the plasma processing chamber 401 through the coaxially introduced multi-slot antenna 403. Thus, plasma was generated in the plasma processing chamber 401. The oxygen gas introduced through the plasma processing gas inlet 405 was plasma processed. Excited and decomposed in the chamber 401 to become active species, transported in the direction of the silicon substrate 402, reacted with TEOT gas, and a tantalum oxide film was formed on the silicon substrate 402 to a thickness of 5 nm.

After the treatment, the withstand voltage, leakage current, and flat band shift were evaluated. The breakdown voltage was as good as 7.3 MV / cm, the leakage current was 4.6 μA / cm ² , and ΔVfb was 0.1 V.

  The microwave plasma processing apparatus shown in FIG. 3 was used to etch the low dielectric constant organic film for semiconductor element interlayer insulation.

As the substrate 302, a φ8 ″ P-type single crystal silicon substrate (plane orientation <100>, which is formed by forming a MOS capacitor and a first-layer wiring and a polyaryl ether film having a thickness of 0.4 μm as an organic film having a low dielectric constant) First, after the silicon substrate 302 is placed on the substrate support base 303, the etching chamber 301 is evacuated through an exhaust system (not shown), and the pressure is reduced to a value of 10 ⁻⁷ Torr. NH ₃ was introduced into the plasma processing chamber 301 through the plasma processing gas inlet 305 at a flow rate of 100 sccm, and then a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted. Then, the inside of the plasma processing chamber 301 was maintained at a pressure of 5 mTorr, and then 100 W of electric power was supplied to the substrate support 302 via the 400 kHz high frequency applying means. In addition, 2.0 kW of power was supplied from the 2.45 GHz microwave power source into the plasma processing chamber 301 via the slotted endless annular waveguide 303. Thus, plasma was generated in the plasma processing chamber 301. The NH ₃ gas introduced through the plasma processing gas inlet 305 is excited and decomposed in the plasma processing chamber 301 to become active species, transported in the direction of the silicon substrate 302, and accelerated by self-bias. The polyaryl ether film was etched by the ions, and the substrate temperature rose only to 10 ° C. by the cooler 307.

  After the etching, the etching rate, the selection ratio, and the etching shape were evaluated. It was confirmed that the etching rate and the selectivity to polysilicon were good at 330 nm / min, 12, the etching shape was almost vertical, and the microloading effect was small.

Thereafter, a second-layer wiring was formed and the IV characteristics of the MOS capacitor were measured. As a result, the breakdown voltage was 10.6 MV / cm and the leakage current was 3.1 A / cm ² .

  Using the microwave plasma processing apparatus shown in FIG. 3, the polysilicon film between the gate electrodes of the semiconductor element was etched.

As the substrate 302, a φ8 ″ P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) having a polysilicon film formed on the top is used. First, the silicon substrate 302 is placed on the substrate support base 303. After the installation, the inside of the plasma processing chamber 301 was evacuated through an exhaust system (not shown), and the pressure was reduced to a value of 10 ⁻⁷ Torr, 300 sccm of CF ₄ gas was supplied through the plasma processing gas inlet 305. Oxygen was introduced into the plasma processing chamber 301 at a flow rate of 20 sccm, and then a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to maintain the inside of the plasma processing chamber 301 at a pressure of 2 mTorr. Next, a high frequency power of 300 W from a high frequency power supply (not shown) of 400 kHz is applied to the substrate support 303 and a 2.45 GHz my power is supplied. A 2.0 kW electric power was supplied from the chrominance power source into the plasma processing chamber 301 via the slotted endless annular waveguide 303. Thus, plasma was generated in the plasma processing chamber 301. Plasma processing gas introduction CF ₄ gas and oxygen introduced through the port 305 are excited and decomposed in the plasma processing chamber 301 to become active species, transported in the direction of the silicon substrate 302, and the polysilicon film is formed by ions accelerated by self-bias. Etched, the cooler 304 only increased the substrate temperature to 80 ° C.

After the etching, the etching rate, the selection ratio, and the etching shape were evaluated. The etched shape was evaluated by observing a cross section of the etched polysilicon film with a scanning electron microscope (SEM). It was confirmed that the etching rate and the selectivity with respect to SiO ₂ were 850 nm / min and 24, respectively, the etching shape was vertical, and the microloading effect was small.

Thereafter, a MOS capacitor was formed and the IV characteristics were measured. As a result, the breakdown voltage was 10.6 MV / cm and the leakage current was 2.7 μA / cm ² .

  Photoresist ashing was performed using the microwave plasma processing apparatus shown in FIG.

As the substrate 302, a φ8 ″ silicon substrate immediately after etching the gate electrode was used. First, after the silicon substrate 302 was placed on the substrate support 303, it was heated to 200 ° C. using a heater 304 and an exhaust system ( The plasma processing chamber 301 was evacuated to 10 ⁻⁴ Torr through a plasma processing gas inlet 305 and oxygen gas was introduced into the plasma processing chamber 301 at a flow rate of 2 slm. Next, a conductance valve (not shown) provided in an exhaust system (not shown) was adjusted to maintain the inside of the processing chamber 301 at 1 Torr.2. In the plasma processing chamber 301, a 2.45 GHz microwave power source was used. 5 kW of power was supplied through the slotted endless annular waveguide 308. Thus, plasma was generated in the plasma processing chamber 301. At this time, the oxygen gas introduced through the plasma processing gas inlet 305 is excited, decomposed, and reacted in the plasma processing chamber 301 to become ozone, which is transported in the direction of the silicon substrate 302, and photo on the substrate 302. The resist was oxidized, vaporized and removed.

After ashing, ashing speed and substrate surface charge density were evaluated. The uniformity of the obtained ashing speed was as extremely large as ± 4.2% (7.5 μm / min), and the surface charge density was as low as 0.5 × 10 ¹¹ cm ⁻² .

Thereafter, a MOS capacitor was formed and the IV characteristics were measured. As a result, the breakdown voltage was 11.0 MV / cm and the leakage current was 3.4 μA / cm ² .

(A) is a schematic diagram of the microwave plasma processing apparatus using the vacuum ultraviolet light shielding plate with oblique holes of the present invention, and (b) is a cross-sectional view of the vacuum ultraviolet light shielding plate with oblique holes. It is process drawing explaining the manufacturing process of the vacuum ultraviolet-light-shielding board with an oblique hole used for this invention, (a) is a perforation type and (b) is a tube bundle sintering type. 1 is a schematic diagram of a microwave plasma processing apparatus using a coaxially introduced multi-slot antenna and a silicon vacuum ultraviolet light shielding plate, which is an example of the present invention. FIG. It is a schematic diagram of a microwave plasma processing apparatus using a slotted endless annular waveguide and a quartz vacuum ultraviolet light shielding plate, which is an example of the present invention. (A) is the schematic diagram of the microwave plasma processing apparatus which is a prior art example, (b) is the figure used in order to demonstrate the generation | occurrence | production principle of plasma.

Explanation of symbols

101, 301, 401, 501 Plasma processing chambers 102, 302, 402, 502 Substrates to be processed 303, 403, 503 Supports 104, 304, 404, 504 Substrate temperature adjusting means 105, 305, 405, 505 Processing gas introducing means 106, 306, 406, 506 Exhaust 307, 407, 507 Dielectric window 308, 407, 508 Flat plate microwave introduction means with slots 109, 309, 409 Vacuum ultraviolet light shielding plate with oblique holes 201 Vacuum ultraviolet light shielding disk 202 Drilling means such as a drill 203 Tube bundle 204 Fan-shaped sintering frame 205 Fan core 206 Fan back 207 Cut surface 208 Circular sintering frame 511 Microwave inlet 512 Circular waveguide 513 Standing wave in pipe 514 Slot 515 Surface wave 516 Surface fixing Standing wave 517 Generating part plasma 518 Plasma valve The

Claims (8)

  A plasma processing chamber in which a part of the partition wall is constituted by a flat plate-shaped microwave transmission window; a substrate support means installed in the plasma processing chamber; a processing gas introduction means into the plasma processing chamber; and the plasma A plasma processing apparatus comprising: exhaust means for evacuating a processing chamber; and flat plate microwave introduction means having a plurality of slots for introducing microwaves into the plasma processing chamber through the microwave transmission window. In addition, a plurality of through holes are formed obliquely between the microwave transmitting window and the substrate supporting means so that the microwave transmitting window cannot be seen through the through holes from the surface of the substrate, and transmits vacuum ultraviolet light. A microwave plasma processing apparatus, characterized in that a flat light-shielding plate made of a non-performing material is provided.   2. The microwave plasma processing apparatus according to claim 1, wherein the vacuum ultraviolet light is vacuum ultraviolet light having a wavelength of 165 nm or less.   The plasma processing apparatus according to claim 1, wherein the shape of the through hole is linear.   The plasma processing apparatus according to claim 1, wherein the shape of the through hole is an elbow shape.   The microwave plasma processing apparatus according to any one of claims 1 to 4, wherein the vacuum ultraviolet light shielding plate with oblique through-holes has two stages of light shielding plates with through-holes.   6. The plasma processing apparatus according to claim 1, wherein the microwave introduction means is a slotted endless annular waveguide.   The plasma processing apparatus according to claim 1, wherein the microwave introduction means is a coaxial introduction flat plate multi-slot antenna.   The material for the vacuum ultraviolet light shielding plate is any one of silica such as quartz, alumina, silicon nitride, aluminum nitride, silicon, aluminum and carbon, or a composite material. The plasma processing apparatus as described.

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