JP2008276984A - Plasma processing apparatus and dielectric window - Google Patents

Abstract

PROBLEM TO BE SOLVED: To damage a dielectric window conventionally used in an electrodeless discharge apparatus, not only the loss of the dielectric window but also the entire processing apparatus when the damage is caused in a state where the inside of the apparatus is decompressed. The present invention solves such a problem and provides a dielectric window capable of reducing the influence on the entire processing apparatus even if the dielectric window is broken.
The dielectric window has a structure in which two or more dielectric plates (110, 111) and a resin layer (112) sandwiched between the dielectric plates are laminated and laminated.
[Selection] Figure 2

Description

  The present invention relates to a plasma processing apparatus using a dielectric window for performing electrodeless discharge, and a dielectric window for the plasma processing apparatus.

  Currently, many processes using plasma generated by high-frequency discharge are employed in the manufacturing process of semiconductor elements such as etching, ashing, and CVD. Various methods such as capacitive coupling method, magnetron method, inductive coupling method, electron cyclotron resonance method, helicon wave method, microwave method, and surface wave method are known as plasma generation methods for performing these plasma processes. Yes. As described above, various plasma generation methods are broadly classified according to positions at which means for supplying high-frequency power such as electrodes, coils, waveguides, and antennas are arranged. That is, electroded discharge in which the means for supplying high-frequency power is arranged at a position directly facing the space for generating plasma, and no means for arranging the means for supplying high-frequency power in a position not directly facing the space for generating plasma. Electrode discharge.

  In the electrodeless discharge, high-frequency power supply means is provided outside the processing container, and the high-frequency power supplied from the high-frequency power supply means is introduced into the processing container through a dielectric window through which high-frequency power can pass. The dielectric window is a part of a wall separating the inside and outside of the processing container, and the high-frequency power supply means is not directly exposed to the plasma generated in the processing container. Therefore, electrodeless discharge does not cause damage to the high-frequency power supply means due to plasma particle bombardment, and there is no possibility of causing metal contamination associated therewith. Therefore, it is suitable for a process that requires a clean process such as film formation, etching, and ashing in a semiconductor manufacturing front end.

  An example of a plasma processing apparatus using electrodeless discharge is shown in FIG. The plasma processing apparatus of FIG. 7 has a processing container 101 whose inside can be depressurized by an exhaust means (not shown) through an exhaust unit 106, and a support for placing a processing substrate 103 inside the processing container 101. 104 is provided. The substrate is, for example, a semiconductor wafer, a glass substrate for a liquid crystal display panel, or a glass substrate for a color filter of a liquid crystal display panel. A gas introduction part 105 for introducing a processing gas is provided on the inner side surface of the processing container. A dielectric window 109 for introducing high-frequency power radiated from the high-frequency power supply means 107 installed outside the processing container is provided in a part of the processing container wall while the inside of the processing container is hermetically sealed. As a material for the dielectric window 109, ceramics such as quartz, silicon nitride, alumina, and aluminum nitride that have high resistance to plasma and low high-frequency power loss are used.

  The high frequency power radiated from the high frequency power supply means passes through the dielectric window 109 and is introduced into the processing container 101. The processing gas in the processing container is excited by the high frequency power introduced into the processing container, and plasma is generated.

Since the dielectric window 109 separates the reduced pressure inside the processing container from the atmospheric pressure outside the processing container, a load due to a pressure difference between the inside and outside of the processing container is applied. Further, when plasma is further generated, high energy electrons and ions flow into the dielectric window, so that the dielectric window 109 may be heated and thermal stress may be generated. For this reason, a structure of an apparatus is known in which the coolant 108 is circulated between the dielectric window 109 and the waveguide to reduce the thermal stress, thereby preventing the dielectric window from being damaged by the thermal stress. ing.
The dielectric window 109 is designed with a structure that can sufficiently withstand these loads and stresses.
JP-A-6-275395

  However, ceramics such as quartz, alumina, and aluminum nitride, which are generally used as a dielectric window material, are brittle materials. When a fine scratch or the like is generated on the surface of the dielectric window made of such a material, there is a possibility that brittle fracture is caused even if the force is smaller than the force that can be naturally withstood. For this reason, for example, if the surface is damaged due to contact with other parts while the dielectric window is repeatedly used, the strength is significantly reduced, and the processing container may be destroyed when the pressure is reduced. When the dielectric window is broken while the inside of the processing container is depressurized, there is a possibility that the fragments pushed by the atmospheric pressure are scattered at once in the processing container and damage the stage supporting the substrate and the inner wall of the processing container. Further, since a large amount of fine dielectric pieces are generated, there is a problem that the apparatus must be stopped for a long time to remove them.

As described above, conventionally, when the dielectric window, which is a consumable part, is damaged, not only the loss of the dielectric window but also the entire processing apparatus is adversely affected. Therefore, various countermeasures have been desired. .
It is an object of the present invention to solve such problems and to provide a plasma processing apparatus and a dielectric window that can reduce the influence on the entire processing apparatus even if the dielectric window is broken.

  In order to solve the above problems, a plasma processing apparatus of the present invention includes a processing container having a dielectric window, means for reducing the pressure inside the processing container, and high-frequency power in the processing container through the dielectric window. A plasma processing apparatus having high-frequency power supply means to be introduced, wherein the dielectric window has a structure in which two or more dielectric plates and a resin layer sandwiched between the dielectric plates are laminated and laminated. Features.

  According to the present invention, in a device that generates plasma using a dielectric window that transmits high-frequency power and processes the substrate, damage to processing device parts other than the dielectric window when the dielectric window is destroyed is suppressed. Is possible.

Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.
Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS.
Here, FIG. 1 is a cross-sectional view of a plasma processing apparatus according to an embodiment of the present invention. In FIG. 1, 101 is a processing container, 102 is a processing chamber, 103 is a base, 104 is a support, 105 is a gas introduction unit, 106 is a gas exhaust unit, 107 is a high-frequency power supply means, and 108 is a dielectric window. A refrigerant 109 is a dielectric window.

  FIG. 2 is a sectional view showing the structure of the dielectric window 109 in the apparatus of FIG. Here, 110 is a dielectric plate facing the outside of the processing vessel, 111 is a dielectric plate facing the inside of the processing vessel, and 112 is a resin film constituting the resin layer. In this processing apparatus, plasma is generated by introducing high-frequency power into the processing container through a dielectric window 109 through which high-frequency power can pass through the processing container decompressed by an exhaust means (not shown).

  As shown in FIG. 2, the dielectric window 109 of the present embodiment has a structure in which a resin film 112 is sandwiched between a dielectric plate 110 and a dielectric plate 111, and they are laminated to be laminated. In the present invention, the dielectric window may have any structure in which at least two or more dielectric plates and a resin film sandwiched between the dielectric plates are laminated and bonded together. For example, as shown in FIG. 3, two resin films 112 may be sandwiched between three dielectric plates 110 and 111 and bonded together. The resin film 112 is bonded to the dielectric plate 110 and the dielectric plate 111 using an adhesive. Alternatively, the resin film 112 may be bonded by a so-called heat sealing method in which the resin film 112 is pressed and heated while being sandwiched between the dielectric plates 110 and 111. In the case of bonding using an adhesive, for example, an acrylic adhesive or a silicon adhesive can be used. In particular, a silicon-based adhesive is excellent in heat resistance and has a low dielectric loss tangent, and thus is suitable for bonding a dielectric plate that transmits high-frequency power and a resin film. The dielectric plates 110 and 111 are preferably made of materials and shapes having sufficient strength to withstand the atmospheric pressure load applied from the outside of the processing vessel and thermal stress. The dielectric plate 110 and the dielectric plate 111 may be made of the same material or different materials. For example, even if the dielectric window is made of a material with a significantly different coefficient of thermal expansion, it is possible to suppress stress peeling caused by the difference in coefficient of thermal expansion by being sandwiched by sandwiching a ductile resin film. It is.

  When the dielectric window according to the present embodiment is used as a window of a decompressed processing container, the entire window composed of a resin film and a dielectric plate laminated with the resin film sandwiched can withstand at least stress caused by atmospheric pressure or the like. What is necessary is just to have thickness. However, it is preferable that the individual dielectric plates constituting the dielectric window alone have a thickness that can withstand stress. For example, when a window having a structure in which two flat dielectric plates are bonded with a resin film (resin layer) is used, even if one dielectric plate is damaged, the other dielectric plate is not affected. For this reason, the vacuum in a processing container is not broken and scattering of a window etc. can be suppressed. Also, even if two dielectric plates are damaged at the same time, it is possible to suppress scattering compared to the conventional dielectric window.

  In the present invention, the thickness of the resin film (resin layer) is not particularly limited as long as the dielectric plates can be bonded to each other and the adhesion can be maintained. For example, a resin film having a thickness in the range of 0.1 mm to 1 mm is used. Is possible.

  The dielectric window of the present invention has a structure in which a resin layer is sandwiched between dielectric plates and they are laminated and laminated, and each dielectric plate is held in close contact with the resin layer. In a conventional dielectric window, for example, when a dielectric window that has been cracked in part is bent to atmospheric pressure or thermal stress, it is brittlely destroyed by atmospheric pressure, and fragments of the dielectric window are scattered in the processing vessel. In some cases, the processing container wall or the support means for the substrate may be damaged. However, the dielectric window of the present invention comprises a dielectric window comprising a plurality of dielectric plates and a resin layer in close contact with them. Even if a portion of the dielectric plate is damaged, other dielectric plates Supports atmospheric pressure, so there is no risk of brittle fracture throughout the dielectric window. In addition, since the dielectric plate is in close contact with the resin layer, it is possible to suppress scattering of fragments that may be caused by cracks. For this reason, it becomes possible to reduce significantly the damage in the processing container by the fragment like the past, and the cleaning load of a fragment.

  Examples of the material of the resin film 112 constituting the resin layer of the present invention include polyethylene terephthalate, polycarbonate, polyamide, polyimide, and polyacetal. Moreover, polyvinyl chloride, polyvinylidene chloride, polyvinyl butyral, and ethylene vinyl acetate copolymer can be used. Furthermore, polytetrafluoroethylene (PTFE) and tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA) can be mentioned. However, after the plasma is generated by the high frequency discharge, the dielectric facing the processing container may be heated by high energy electrons or ions flowing into the surface. When the temperature of the dielectric rises above the melting heat temperature of the resin film 112, the resin film 112 is greatly thermally deformed or melted, and there is a possibility that the adhesiveness with the dielectric is lost. For this reason, it is preferable that the resin film 112 has a high heat resistance temperature, and it is preferable to use a fluorine resin film (heat-resistant resin film containing fluorine) having high heat resistance such as PTFE or PFA.

In order to prevent the temperature of the resin film from rising, a dielectric material that does not directly face plasma is at least 20 W / m · K or more, more preferably 100 W / m · K or more, and a refrigerant or the like. It is preferable to cool the dielectric using
For example, when both the dielectric plate facing the inside of the processing container and the dielectric material facing the outside of the processing container are made of quartz, the thermal conductivity of quartz is about 1.6 W / m · K, which is extremely high. It is easy to store heat because it is low. For this reason, it is difficult to lower the temperature of the resin film sandwiched between the dielectric plates even if the dielectric window is cooled by the refrigerant from the outside of the processing container. However, when the dielectric plate other than the dielectric plate facing the plasma is made of a material having a thermal conductivity of at least 20 W / m · K, more preferably 100 W / m · K, the heat generated by the inflow of plasma is reduced. Heat can be removed quickly. For this reason, it is possible to prevent the temperature of the resin film from rising.

  Examples of the dielectric material used for the dielectric window of the present invention include quartz, alumina, zirconia, silicon nitride, and aluminum nitride. Of these, alumina has a high thermal conductivity of about 30 W / m · K, and aluminum nitride has a high thermal conductivity of about 160 W / m · K. The dielectric plate made of such a material is suitable for suppressing the temperature rise of the resin film sandwiched between the dielectric plates.

  As another structure of the dielectric window of the present invention, as shown in FIG. 4, in addition to the dielectric window structure shown in FIG. 2, a resin film 113 is further adhered to the surface of the dielectric plate on one side. There may be. The surface to which the resin film 113 is in close contact is the side facing the outside of the processing container. As a result, it becomes possible to further increase the holding force when the dielectric plate is broken, and to suppress the consumption such as generation of minute scratches on the dielectric surface, thereby extending the life of the dielectric window. It becomes possible. The resin film 112 sandwiched between the dielectric plates and the resin film 113 adhered to the dielectric surface may be the same material or different materials.

Next, a plasma processing apparatus and a plasma processing method to which a dielectric window, which is a feature of the present invention, is described.
In FIG. 1, a processing chamber 102 accommodates a substrate 103 and performs a plasma treatment on the substrate to be processed 103 under reduced pressure. In FIG. 1, a gate valve and the like for transferring the base 103 to and from a load lock chamber (not shown) are omitted.

The substrate to be processed 103 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 substances. In addition, examples thereof include organic films and sheets such as polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide.
The base 103 is placed on the support 104. If necessary, the support 104 may be configured to be height adjustable. Further, the support 104 may incorporate a temperature control means to adjust the substrate temperature during the plasma processing.

  The gas introduction unit 105 is provided on the side wall of the processing vessel 101 and supplies a plasma processing gas into the processing chamber. The gas introduction part 105 is a part of gas supply means. The gas supply means includes a gas supply source, a valve, a mass flow controller, and a gas introduction pipe connecting them, and supplies a processing gas and a discharge gas for obtaining a predetermined plasma when excited by microwaves. A rare gas such as Xe, Ar, or He may be added at least during ignition for rapid ignition of plasma. Since the rare gas is not reactive, it does not adversely affect the substrate 103 and is easily ionized, so that the plasma ignition speed can be increased.

As a gas used when a thin film is formed on the substrate 103 by the CVD method, generally known gases can be used.
The raw material of the gas for forming a Si-based semiconductor thin film such as a-Si, poly-Si, or SiC is a compound that is in a gas state at normal temperature and pressure or can be easily gasified. For example, inorganic silanes such as SiH ₄ and Si ₂ H ₆ , tetraethylsilane (TES), tetramethylsilane (TMS), dimethylsilane (DMS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), etc. Organosilanes. Alternatively, halogens such as 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. Silanes. 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 for forming a Si compound-based thin film such as Si ₃ N ₄ or SiO ₂ , a compound that is in a gas state at normal temperature and pressure or can be easily gasified can be used. Such compounds include inorganic silanes such as SiH ₄ and Si ₂ H ₆ . In addition, there are organic silanes such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), octamethylcyclotetrasilane (OMCTS), dimethyldifluorosilane (DMDFS), and dimethyldichlorosilane (DMDCS). Further, halogens such as 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. There are silanes. In this case, the nitrogen source gas or the oxygen source gas introduced at the same time includes N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS), O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ can be mentioned.

Examples of the raw material for forming a metal thin film such as Al, W, Mo, Ti, and Ta include the following organic metals and metal halides. Examples of the organic metal include trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), and tungsten carbonyl (W (CO) ₆ ). In addition, there are molybdenum carbonyl (Mo (CO) ₆ ), trimethyl gallium (TMGa), and triethyl gallium (TEGa). Examples of the metal halide include 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 raw materials for forming a metal compound thin film such as Al ₂ O ₃ , AlN, Ta ₂ O ₅ , TiO ₂ , TiN, and WO ₃ , the following organic metals or metal halides can be exemplified. Examples of the organic metal include trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), and tungsten carbonyl (W (CO) ₆ ). In addition, there are molybdenum carbonyl (Mo (CO) ₆ ), trimethyl gallium (TMGa), and triethyl gallium (TEGa). Examples of the metal halide include 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 Disilazane (HMDS) is mentioned.

As the etching gas for etching the substrate surface, 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.
Examples of the ashing gas used for ashing and removing organic components on the substrate surface such as a photoresist include O ₂ , O ₃ , H ₂ O, NO, N ₂ O, NO ₂ , and H ₂ .

  When the plasma processing apparatus according to this embodiment is also applied to surface modification, various types of processing can be performed by appropriately selecting a gas to be used. For example, by using Si, Al, Ti, Zn, Ta or the like as a substrate or a surface layer, oxidation treatment or nitridation treatment of these substrates or surface layers, doping treatment of B, As, P or the like can be performed. Furthermore, the film forming technique employed in this embodiment 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 for oxidizing the surface of the substrate to be processed 103 include O ₂ , O ₃ , H ₂ O, NO, N ₂ O, and NO ₂ . Examples of the nitriding gas for nitriding the substrate to be processed 103 include N ₂ , NH ₃ , N ₂ H ₄ , hexamethyldisilazane (HMDS), and the like.
As cleaning / ashing gases for cleaning organic substances on the surface of the substrate or ashing and removing organic components on the surface of the substrate to be processed 103 such as photoresist, O ₂ , O ₃ , H ₂ O, NO, N _{2 O,} such as NO 2, _{H 2} and the like. In addition, as a cleaning gas for cleaning the inorganic substance on the surface of the substrate, F ₂ , CF ₄ , CH ₂ F ₂ , C ₂ F ₆ , C ₄ F ₈ , CF ₂ Cl ₂ , SF ₆ , NF _{3 and the} like can be used. Can be mentioned.

  The exhaust unit 106 is provided on the gas downstream side of the processing chamber, and constitutes a pressure adjustment mechanism together with a pressure adjustment valve, a pressure gauge, a vacuum pump, and a control unit (not shown). That is, a control unit (not shown) adjusts the pressure in the processing chamber 102 by the degree of opening of the valve so that the pressure gauge that detects the pressure in the processing chamber 102 has a predetermined value while operating the vacuum pump. Adjust by controlling. As a result, the internal pressure of the processing chamber 102 is controlled to a pressure suitable for processing through the exhaust unit 106. The pressure is preferably in the range of 13 mPa to 1330 Pa, more preferably in the range of 665 mPa to 665 Pa. The pressure adjustment valve is, for example, a gate valve with a pressure adjustment function made by VAT or an exhaust slot valve made by MKS. The vacuum pump is composed of, for example, a dry pump, a turbo molecular pump (TMP), or the like, and is connected to the exhaust unit 106 via a pressure adjustment valve such as a conductance valve (not shown).

The high frequency power supply means 107 is a means for oscillating a high frequency, and dissociates the processing gas in the processing chamber decompressed through the dielectric window to generate plasma.
The plasma excitation method in the present embodiment may be any method as long as high-frequency power is supplied into the processing vessel through the dielectric window to perform electrodeless discharge. For example, there are plasma excitation methods in various modes such as electron cyclotron resonance, inductive coupling, and surface wave. Examples of high-frequency power supply means for exciting such a mode of plasma include a coil, a waveguide, and a slotted antenna. The high frequency oscillated from the high frequency power supply means is appropriately selected from, for example, frequencies between several tens of kHz to several tens of GHz.

  In order to prevent the temperature rise of the dielectric window during discharge, it is preferable to circulate the coolant 108 on the outer surface of the dielectric window 109 and cool the surface of the dielectric window. As the refrigerant 108, any material can be selected as long as it does not impede permeation of high-frequency power, such as a gas such as dry air or a liquid such as water or oil.

Plasma processing using the present plasma processing apparatus is performed as follows.
First, the base 103 is set on the support 104. Next, the inside of the processing vessel 101 of the plasma processing apparatus is sufficiently exhausted through the gas exhaust unit 106 by exhaust means (not shown). Next, a gas having a predetermined flow rate is introduced into the processing chamber 102 via a gas introduction unit 105 by a gas introduction unit (not shown), and a desired pressure is obtained by a conductance valve (not shown) provided in the exhaust unit. Hold. Subsequently, a high frequency is oscillated from the high frequency power supply means 107 and supplied into the processing chamber via the dielectric window 109. The processing gas is dissociated by the high frequency discharge, and plasma is generated in the processing chamber 102. Various plasma treatments of the substrate are performed by the plasma thus generated.

  During the discharge, a coolant for cooling the dielectric window 109 is circulated on the atmosphere side surface of the dielectric window 109 to suppress the temperature rise of the dielectric window. As a result, it is possible to suppress thermal deformation of the resin film in close contact with each dielectric of the dielectric window 109 and to maintain adhesion with the dielectric. However, a refrigerant for cooling the dielectric window is not necessarily required when there is no risk of heating the dielectric window, such as when there is little inflow of plasma particles into the dielectric window or there is little loss heating due to high frequency power. .

Hereinafter, specific examples of application of the plasma processing apparatus using the dielectric window, which is a feature of the present invention, will be described by way of examples. However, the present invention is not limited to these examples.
[Example 1]
A processing apparatus according to Embodiment 1 of the present invention will be described with reference to FIG.
The processing apparatus of this embodiment is a processing apparatus that generates surface wave interference plasma and processes a substrate. Here, 101 is a processing container, 102 is a processing chamber, 103 is a substrate, 104 is a stage, 105 is a gas introduction part, and 106 is a gas exhaust part. Reference numeral 107 denotes a slotless endless annular waveguide for supplying microwaves to the processing chamber, 109 denotes a dielectric window for introducing microwaves, and 108 denotes a refrigerant for cooling the dielectric window 109. .

  The processing container 101 is made of an aluminum alloy and has an inner diameter of 350 mm. The dielectric window 109 has the structure shown in FIG. 2, and is formed by bonding a quartz flat plate 111, a PTFE resin film 112, and an alumina ceramic flat plate 110 with a silicon adhesive. Thicknesses of 9 mm for the quartz flat plate 111, 0.35 mm for the PTFE resin film 112, and 7 mm for the alumina ceramic flat plate 110 were used. The slotted endless annular waveguide 107 is in TE10 mode, the inner wall cross-sectional dimension is 27 mm × 96 mm (inner wavelength 158.8 mm), and the waveguide center diameter is 151.6 mm (one circumference is three times the inner wavelength) ) Was used. A slot for introducing microwaves into the processing chamber 102 is formed on the H surface of the slotted endless annular waveguide 107. 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.

First, the inside of the processing vessel 101 was evacuated through the exhaust unit 106 and the pressure was reduced to a value of 1 × 10 ⁻² Pa. Subsequently, oxygen gas was introduced into the processing chamber 102 through the gas introduction unit 105 at a flow rate of 100 sccm. Subsequently, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to keep the processing chamber 102 at 400 Pa. Next, 1 kW of electric power was supplied from a 2.45 GHz microwave power source (not shown) through the slotted endless annular waveguide 107 to generate surface wave plasma. In order to suppress the temperature rise of the dielectric window during discharge, cooling was performed by applying dry air kept at room temperature to the surface of the dielectric window. Dummy running was repeated by the above method, but no abnormality was found in the dielectric window 109.

  Next, similar dummy running was performed using a dielectric window in which a minute scratch was intentionally made on the surface of the alumina ceramic plate constituting the dielectric window. As a result, during dummy running, cracks originating from the minute scratches occurred in the alumina ceramic flat plate. However, such a crack stayed in the alumina ceramic flat plate, the quartz flat plate portion was not damaged, and the vacuum in the processing vessel was not broken.

[Example 2]
A processing apparatus according to Embodiment 2 of the present invention will be described with reference to FIG.
The processing apparatus of this embodiment is a processing apparatus that generates inductively coupled plasma and processes a substrate. Here, 101 is a processing container, 102 is a processing chamber, 103 is a substrate, 104 is a stage, 105 is a gas introduction part, and 106 is a gas exhaust part. Reference numeral 107 denotes a spiral coil that oscillates RF high frequency, 109 denotes a dielectric window for introducing the RF high frequency, and 108 denotes a refrigerant for cooling the dielectric window 109.

  The processing container 101 is made of an aluminum alloy and has an inner diameter of 350 mm. The dielectric window 109 has the structure shown in FIG. 2, and is formed by bonding a quartz flat plate, a PTFE resin film, and an aluminum nitride flat plate with a silicon-based adhesive. Thicknesses of 8 mm for the quartz flat plate 111, 0.6 mm for the PTFE resin film 112, and 5 mm for the aluminum nitride ceramic flat plate 110 were used.

First, an 8-inch P-type Si wafer was placed on the stage (support) 104 as the substrate 103, and then the inside of the processing vessel 101 was evacuated through the exhaust unit 106, and the pressure was reduced to a value of 1 × 10 ⁻² Pa. . Subsequently, oxygen gas was introduced into the processing chamber 102 through the gas introduction unit 105 at a flow rate of 50 sccm. Subsequently, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted, and the processing chamber 102 was maintained at 2.6 Pa. Next, 500 W of electric power was supplied from a 13.56 MHz RF power source (not shown) to the spiral coil to generate inductively coupled plasma. In order to suppress the temperature rise of the dielectric window during discharge, the dielectric window surface was cooled by applying dry air kept at room temperature. Dummy running was repeated by the above method, but no abnormality was found in the dielectric window 109.

  Next, similar dummy running was performed using dielectric windows in which minute scratches were intentionally made on the surfaces of the quartz flat plate and the aluminum nitride ceramic flat plate constituting the dielectric window. As a result, during the dummy running, cracks originating from the minute scratches occurred on both the quartz flat plate and the aluminum nitride ceramic flat plate. As a result, although the vacuum inside the processing vessel was broken, there was very little scattering of quartz and aluminum nitride ceramics into the processing vessel, and the stage and the processing vessel wall were not significantly damaged by the fragments.

[Example 3]
Using the plasma processing apparatus shown in FIG. 6, ashing of the photoresist was performed. However, in this embodiment, a dielectric window having a structure as shown in FIG. That is, the dielectric window 109 is formed by bonding a quartz flat plate, a PTFE resin film, and an aluminum nitride ceramic flat plate with a silicon-based adhesive, and further bonding a PTFE resin film on the surface of the aluminum nitride ceramic flat plate. Thicknesses of 8 mm for the quartz flat plate 111, 0.35 mm for the PTFE resin film 112, and 5 mm for the aluminum nitride ceramic flat plate 110 were used. The substrate 103 was a φ12 ″ P-type single crystal silicon wafer, and the surface thereof was coated with a photoresist and further ion-implanted.

First, a silicon wafer was placed on the stage 104, and then the inside of the processing vessel 101 was evacuated through the exhaust unit 106, and the pressure was reduced to a value of 1 × 10 ⁻² Pa. Subsequently, oxygen gas was introduced into the processing chamber 102 through the gas introduction unit 105 at a flow rate of 50 sccm. Subsequently, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted, and the processing chamber 102 was maintained at 2.6 Pa. Next, 500 W of electric power was supplied from a 13.56 MHz RF power source (not shown) to the spiral coil to generate inductively coupled plasma. In order to suppress the temperature rise of the dielectric window during discharge, the dielectric window surface was cooled by applying dry air kept at room temperature.

  An ashing process using the oxygen plasma thus generated was performed. As a result, the resist on the silicon substrate 103 was completely removed by ashing, and no residue was found. Even after repeating the work of removing the dielectric window and cleaning the inside of the device after performing a certain number of ashing processes, the surface of the dielectric window is less likely to be damaged by contact, etc. Compared to conventional dielectric windows The service life was greatly extended.

[Example 4]
The silicon wafer was oxidized using the plasma processing apparatus shown in FIG. However, in this embodiment, a dielectric window having a structure as shown in FIG. 3 was used as the dielectric window. That is, the dielectric window 109 is formed by bonding five layers of a quartz flat plate, a PTFE resin film, an aluminum nitride ceramic flat plate, a PTFE resin film, and an aluminum nitride ceramic flat plate with a silicon-based adhesive. Thicknesses of 8 mm for the quartz flat plate 111, 0.35 mm for the PTFE resin film 112, and 5 mm for the aluminum nitride ceramic flat plate 110 were used. As the substrate 103, a φ12 ″ P-type single crystal silicon wafer was used.

First, a silicon wafer whose surface was cleaned by a known RCA cleaning method was placed on the stage 104, and then the inside of the processing vessel 101 was evacuated through the exhaust unit 106, and the pressure was reduced to a value of 1 × 10 ⁻² Pa. . Subsequently, oxygen gas was introduced into the processing chamber 102 through the gas introduction unit 105 at a flow rate of 100 sccm. Subsequently, a conductance valve (not shown) provided in the exhaust system (not shown) was adjusted to keep the processing chamber 102 at 400 Pa. Subsequently, 1 kW of electric power was supplied from a 2.45 GHz microwave power source (not shown) via the slotted endless annular waveguide 107 to generate surface wave plasma. In order to suppress the temperature rise of the dielectric window during discharge, the dielectric window surface was cooled by applying dry air kept at room temperature.

  The silicon wafer was oxidized by the oxygen plasma thus generated. As a result, the silicon wafer 103 was oxidized to form a silicon oxide film having a thickness of 10 nm. When the electrical characteristics of the silicon oxide film thus formed were examined, it was found that the breakdown voltage was as good as about 13 MV / cm.

It is a schematic diagram of the microwave plasma processing apparatus which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the dielectric material window structure of the apparatus of FIG. It is a general | schematic fragmentary enlarged view which shows another form of the dielectric material window which concerns on this invention. It is a general | schematic fragmentary enlarged view which shows another form of the dielectric material window which concerns on this invention. It is a schematic sectional drawing which shows the surface wave interference plasma processing apparatus to which the dielectric material window based on this invention is applied. It is a schematic sectional drawing which shows the inductively coupled plasma processing apparatus to which the dielectric window which concerns on this invention is applied. It is a schematic sectional drawing of the electrodeless discharge plasma processing apparatus which is a prior art example and is also an example of the application object of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Processing container 102 Processing chamber 103 Base 104 Support means 105 Gas introduction part 106 Exhaust part 107 High frequency electric power supply means 108 Refrigerant 109 Dielectric window 110, 111 Dielectric plate 112 Resin film (resin layer)
113 Resin film

Claims (6)

A plasma processing apparatus having a processing container having a dielectric window, means for reducing the pressure inside the processing container, and high-frequency power supply means for introducing high-frequency power into the processing container through the dielectric window,
The plasma processing apparatus, wherein the dielectric window has a structure in which two or more dielectric plates and a resin layer sandwiched between the dielectric plates are laminated together.   A dielectric plate other than the dielectric plate facing the inside of the processing container of the dielectric window has a thermal conductivity of 20 W / m · K or more, and the surface of the dielectric plate facing the outside of the processing container is liquid or gas. The plasma processing apparatus according to claim 1, further comprising means for cooling with the refrigerant.   3. The plasma processing apparatus according to claim 1, wherein the dielectric plates other than the dielectric plate facing the processing container are made of aluminum nitride.   The plasma processing apparatus according to claim 1, wherein the resin layer is made of a heat-resistant resin film containing fluorine.   The plasma processing apparatus according to claim 1, wherein a resin film is further bonded to a surface of a dielectric plate facing the outside of the processing container of the dielectric window.   The dielectric window according to any one of claims 1 to 5.

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