JP2012049065A - Plasma processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal antenna type plasma processing apparatus capable of achieving reduction in the volume of a vacuum container, efficient utilization of high-frequency power, and efficient utilization of supplied gas.SOLUTION: The plasma processing apparatus includes one or more antenna openings 22 formed in a wall surface of a vacuum container 4; a lid 24 for covering an external surface of the vacuum container; antenna conductors 26 provided inside the respective antenna openings 22; and dielectric cups 30 that cover the antenna conductors 26 in the respective antenna openings 22. Each of the dielectric cups 30 has a plurality of small holes in the bottom face. In the respective dielectric cups 30, there are provided fillers 38 made of dielectric, which have gas passages for guiding gas 34 introduced from gas introduction parts 36 to the respective small holes.

Description

  The present invention relates to a plasma processing apparatus that performs processing such as film formation by CVD, etching, ashing, sputtering, etc. on a substrate using plasma, more specifically, an antenna conductor provided in a vacuum vessel has a high frequency. The present invention relates to an inductively coupled and internal antenna type plasma processing apparatus in which a gas is ionized by an induced electric field generated by passing an electric current to generate plasma, and the substrate is processed using the plasma.

  The internal antenna type refers to an antenna having a structure in which an antenna conductor for high-frequency discharge is disposed in a vacuum vessel through a current introduction terminal (feedthrough).

  FIG. 1 shows an example around one antenna constituting a conventional inductively coupled and internal antenna type plasma processing apparatus. Structures similar to this are described in, for example, Patent Documents 1 and 2 and Non-Patent Document 1.

  In this conventional plasma processing apparatus, one or more antennas 70 having a structure in which a U-shaped or U-shaped antenna conductor 66 is covered with a dielectric 68 are attached so as to protrude into the vacuum vessel 64.

  A plurality of antennas 70 are provided in accordance with the dimensions of the substrate 2 to be processed provided in the vacuum vessel 64. A plurality of antennas 70 are arranged on the ceiling surface of the vacuum vessel 64 facing the processing surface of the substrate 2 as in the example shown in FIG. 2 (see, for example, Patent Document 2), and when both are used together (see, for example, Non-Patent Document 1).

  A gas introduction section for introducing a gas necessary for generating the plasma 76 into the vacuum vessel 64 is provided at an appropriate location on the ceiling surface or side surface of the vacuum vessel 64.

  The gas is introduced into the vacuum vessel 64 and a high-frequency current is passed through the antenna 70 (specifically, the antenna conductor 66) to generate a high-frequency magnetic field around the antenna 70, thereby generating an induction electric field. . Electrons are accelerated by the induced electric field to ionize the gas, and plasma 76 is generated around the antenna 70. With this plasma 76, the substrate 2 can be subjected to desired processing such as film formation by CVD, etching, and ashing.

  As an alternative to the internal antenna type, there is an external antenna type having a structure in which an antenna conductor for high-frequency discharge is disposed outside a vacuum container with a dielectric window holding a vacuum interposed (see, for example, Patent Document 3). ).

  Compared with the external antenna type, the internal antenna type employed in the above prior art and the present invention has a pressure (atmospheric pressure) applied to the dielectric covering the antenna conductor (dielectric 68 or dielectric cup 30 described later). Since the thickness of the dielectric can be reduced, high-frequency power can be efficiently supplied to the plasma from the vicinity thereof, and there is an advantage that the power absorption efficiency into the plasma is high. (For example, see paragraph 0005 of Patent Document 1 and page 194, right column of Non-Patent Document 1).

JP2007-220600A (FIGS. 2 and 8) JP 2004-39719 A (FIGS. 1 and 3) Japanese Patent Laying-Open No. 2005-285564 (FIG. 1)

Yuichi Setsuhara, “Plasma generation control technology for next generation meter-class large-area processes using multi-low inductance internal antennas”, J. Plasma Fusion Res. Vol. 84, No. 4 (2008), p. 193 -198

  The conventional plasma processing apparatus has the following problems.

(A) A certain distance L ₁ is secured between the antenna 70 and the substrate 2 in order to make the plasma 76 generated by the plurality of discretely arranged antennas 70 uniform on the substrate 2. In addition to this, since it is necessary to secure a distance L ₂ (for example, about 100 mm) that the antenna 70 protrudes into the vacuum container 64, the vacuum container 64 is equivalent to this distance L _2. The volume of must be increased. Accordingly, the exhaust capacity of the vacuum exhaust device for the vacuum vessel 64 must be increased.

  (B) Although the plasma 76 is generated around the antenna 70, in detail, since a strong induction electric field is generated inside the U-shaped or U-shaped antenna 70, the plasma 76 is generated around that area. To do. This generates plasma 76 at a position far from the substrate 2. The substrate 2 is processed by utilizing the diffusion of the plasma 76 to the substrate 2. Since the plasma density is approximately inversely proportional to the square of the distance, if the generation position of the plasma 76 is far as described above, The plasma 76 cannot be efficiently used for processing the substrate 2. In the end, this means that high-frequency power, which is an energy source for plasma generation, cannot be used efficiently.

  (C) In the prior art, gas is introduced into the vacuum vessel 64 from a gas introduction portion provided at an appropriate location on the ceiling surface or side surface of the vacuum vessel 64, and the entire vacuum vessel 64 has a substantially uniform gas pressure. Thus, since the plasma 76 is generated, the gas is supplied in the same way to a place where it is not necessary for plasma generation, and therefore the supply gas cannot be used efficiently.

  Accordingly, the main object of the present invention is to enable a reduction in volume of a vacuum vessel, efficient use of high-frequency power, and efficient use of supply gas in an internal antenna type plasma processing apparatus.

  The plasma processing apparatus according to the present invention generates a plasma by ionizing a gas by an induced electric field generated by flowing a high-frequency current through an antenna conductor provided in a vacuum vessel, and processes the substrate using the plasma. An inductively coupled and internal antenna type plasma processing apparatus, wherein the holder is provided in the vacuum vessel and holds the substrate, one or more antenna openings provided on the wall of the vacuum vessel, A lid that covers the surface of each antenna opening outside the vacuum container; the antenna conductor provided in each antenna opening; a bottom surface located on the holder side; a side surface connected to the bottom surface; and a bottom surface A plurality of small holes provided, the antenna openings covering the antenna conductors in the antenna openings, and the side surfaces of the antenna openings. Each of the dielectric cups provided so as to be close to the wall surface of the opening for the tenor, a gas introduction portion for introducing the gas into each of the dielectric cups, and each of the dielectric cups are filled, And a dielectric filling having a gas flow path for guiding the gas introduced from the gas introduction part to each small hole on the bottom surface of the dielectric cup, and high frequency power to each antenna conductor. And a high-frequency power source for supplying the high-frequency current to each antenna conductor.

  In this plasma processing apparatus, the gas introduced into each dielectric cup is guided to each small hole of the dielectric cup through the gas flow path of the filling in the dielectric cup. And is supplied near the outside of the bottom surface of each dielectric cup.

  In addition, a high-frequency magnetic field is generated around each antenna conductor by supplying a high-frequency current to each antenna conductor, but each dielectric cup is filled with a filler, and the side surface of each dielectric cup is used for the antenna. Since it is close to the wall of the opening and electrons cannot sufficiently travel in the space inside each dielectric cup and outside the side surface, plasma generation is prevented, and plasma is generated only near the outside of the bottom surface of each dielectric cup. This is the plasma generation region.

  In this way, plasma can be generated only in the plasma generation region near the outside of the bottom surface of each dielectric cup, and gas is supplied to the plasma generation region from its immediate vicinity, so that the gas in the plasma generation region can be supplied. The pressure can be increased locally.

  The distance between the side surface of the dielectric cup and the wall surface of the antenna opening in which the dielectric cup is housed is preferably 0 mm to 5 mm.

  The filler is, for example, a large number of dielectric grains or a large number of dielectric short tubes.

  The present invention has the following effects.

  (A) Since each dielectric cup is filled with a filler and the side surface of the dielectric cup is close to the wall surface of the antenna opening, the plasma in the inner space of each dielectric cup and the outer space of the side surface Generation can be prevented and plasma can be generated only in the plasma generation region near the outside of the bottom surface of each dielectric cup. Therefore, the high frequency power for plasma generation can be efficiently supplied to the plasma generated in the plasma generation region, so that the high frequency power can be used efficiently.

  (A) Since each plasma generation region is located closer to the substrate than each antenna conductor, the plasma generated in each plasma generation region can be efficiently used for processing the substrate. Therefore, for this reason as well, high-frequency power can be used efficiently.

  (C) The gas introduced into each dielectric cup can be supplied from the immediate vicinity to each plasma generation region near the outside of the bottom surface through each small hole on the bottom surface of each dielectric cup. Therefore, the gas pressure in each plasma generation region can be locally increased. Therefore, high-density plasma can be generated by each plasma generation region, and the supply gas can be used efficiently.

  (D) Since the antenna conductor is provided in the antenna opening provided on the wall surface of the vacuum vessel, the antenna conductor protrudes into the vacuum vessel when the distance between the antenna conductor and the substrate is substantially the same. The volume of the vacuum vessel can be reduced as compared with the related art. Therefore, the exhaust capacity of the vacuum exhaust device for the vacuum vessel can be reduced.

It is the schematic which shows an example of one antenna periphery which comprises the conventional inductively coupled type | mold and internal antenna type plasma processing apparatus. It is sectional drawing which shows one Embodiment of the plasma processing apparatus which concerns on this invention. FIG. 3 is an enlarged front view showing the periphery of one antenna in FIG. 2. FIG. 3 is a right side view around the antenna of FIG. 2. FIG. 3 is a bottom view around the antenna of FIG. 2, and illustration of a filler is omitted. It is a figure which shows the example which changed the position of the gas introduction part of FIG. It is a figure which shows the modification of FIG. It is a figure which expands and partially shows the example in case a filler is many dielectric short tubes. It is a figure which shows the other example of a coil-shaped antenna conductor with a dielectric cup, and illustration of the filler is abbreviate | omitted. It is a top view which shows an example of a spiral antenna conductor. It is a top view which shows an example of two rod-shaped antenna conductors. It is a top view which shows an example of a planar antenna conductor.

  An embodiment of the plasma processing apparatus according to the present invention is shown in FIG. 2, and the periphery of one antenna is enlarged and shown in FIGS.

  This plasma processing apparatus generates a plasma 46 by ionizing a gas 34 by an induced electric field generated by flowing a high-frequency current through an antenna conductor 26 provided in the vacuum vessel 4, and uses the plasma 46 to form a substrate 2. It is an inductively coupled and internal antenna type plasma processing apparatus for performing processing.

  The substrate 2 is, for example, a flat panel display (FPD) substrate such as a liquid crystal display or an organic EL display, a flexible substrate for a flexible display, or the like, but is not limited thereto.

  The processing applied to the substrate 2 is, for example, film formation by a CVD method, etching, ashing, sputtering, or the like.

  This plasma processing apparatus is also called a plasma CVD apparatus when a film is formed by CVD, a plasma etching apparatus when etching is performed, a plasma ashing apparatus when ashing is performed, and a plasma sputtering apparatus when sputtering is performed.

  The plasma processing apparatus will be described in detail. The vacuum vessel 4 is made of, for example, metal, and the inside thereof is evacuated by the evacuation apparatus 8.

  A holder 10 that holds the substrate 2 is provided in the vacuum container 4. In this example, the holder 10 is supported by the shaft 11. A bearing portion 12 having an electrical insulation function and a vacuum sealing function is provided at a portion where the shaft 11 penetrates the vacuum vessel 4. As in this example, a negative bias voltage may be applied to the holder 10 from the bias power supply 14 via the shaft 11. The bias voltage may be a negative pulse voltage. With such a bias voltage, for example, the energy when positive ions in the plasma 46 are incident on the substrate 2 can be controlled to control the crystallinity of the film formed on the surface of the substrate 2.

  One or more antenna openings 22 are provided on the wall surface of the vacuum vessel 4 so as to face the substrate 2 on the holder 10. More specifically, a plurality of antenna openings 22 are provided on the ceiling surface 6 of the vacuum vessel 4 so as to face the substrate 2 on the holder 10. Each antenna opening 20 is provided in each antenna opening 22. Each antenna unit 20 includes a lid 24, an antenna conductor 26, a dielectric cup 30, a gas introduction unit 36, and a filling 38, respectively. These are described in detail below.

  What is necessary is just to determine the planar shape of each antenna opening 22 and the antenna part 20, a number, arrangement | positioning, etc. according to the dimension, shape, etc. of the board | substrate 2 to process. In the example shown in FIG. 2, a plurality of antenna openings 22 are provided on the ceiling surface 6 facing the substrate 2 at substantially equal intervals in a range wider than the substrate 2, and the antenna portions 20 are provided in the respective antenna openings 22. ing.

  An example of the structure of each antenna unit 20 will be described in detail mainly with reference to FIGS.

  The surface of each antenna opening 22 outside the vacuum container 4 (specifically, its ceiling surface 6) is closed by a lid 24. Between both 4 and 24, a packing 40 for vacuum sealing is provided. More specifically, the lid 24 is a metal flange in this example.

  An antenna conductor 26 is provided in each antenna opening 22. In this example, each antenna conductor 26 has a coil shape (more precisely, a spiral coil shape, and so on). Current feed terminals (feedthroughs) 42 having a vacuum sealing function and an electrical insulation function are provided at portions where the feeding portions 28 and 29 at both ends of the antenna conductor 26 penetrate the lid 24, respectively.

  The planar shape of the antenna conductor 26 may be determined according to the shape of the substrate 2 to be processed. In the example shown in FIGS. 3 to 5 and the like, the planar shape of the antenna conductor 26 is an oval (in other words, a racetrack shape; the same applies hereinafter) (see FIG. 5).

  The number of turns of the coiled antenna conductor 26 is 1.5 turns in this example, but is not limited to this.

  Each antenna conductor 26 may be cooled by flowing a coolant such as cooling water through each antenna conductor 26. The same applies to other examples described later.

  The lid 24 may be an insulating flange as in the example shown in FIG. 7, and the current introduction terminal 42 may be omitted. In that case, for example, a vacuum seal packing 41 may be provided in a portion where the power feeding portions 28 and 29 of the antenna conductor 26 penetrate the lid 24. The material of the insulator is, for example, quartz or alumina, but is not limited thereto.

  A dielectric cup 30 is provided in each antenna opening 22 so as to cover each antenna conductor 26. Each dielectric cup 30 has a cup shape (in other words, a bottomed cylindrical shape) having a bottom surface 31 located on the holder 10 (see FIG. 2) side and a side surface 32 connected to the bottom surface 31.

  The planar shape of the dielectric cup 30 may correspond to the planar shape of the antenna conductor 26, and the planar shape of the antenna opening 22 may correspond to the planar shape of the dielectric cup 30. In this example, since the planar shape of the antenna conductor 26 is oval as described above, the planar shapes of the dielectric cup 30 and the antenna opening 22 are also oval (see FIG. 5).

  Each dielectric cup 30 is provided in the antenna opening 22 such that its side surface 32 is close to the wall surface of the antenna opening 22. In other words, the antenna opening 22 is slightly larger than the dielectric cup 30. Both of them may have substantially the same dimensions, and the side surface 32 of the dielectric cup 30 may be in contact with the wall surface of the antenna opening 22.

  A plurality of small holes 33 are provided on the bottom surface 31 of the dielectric cup 30. By making the holes small, the gas 34 introduced into the dielectric cup 30 from the gas introduction portion 36 can be passed through the small holes 33, but plasma 46 described later enters the dielectric cup 30. Can be prevented. From this point of view, each small hole 33 is preferably a small hole whose diameter is sufficiently smaller than the thickness of the bottom surface 31 (for example, about 1/5 to 1/10). By providing the plurality of small holes 33, more specifically, by providing the plurality of small holes 33 in a dispersed manner, the gas 34 can be uniformly supplied to the plasma generation region 44 described later.

  The dielectric cup 30 may be attached to the lid 24 and supported from the lid 24 as in the example shown in FIG. 3 or the like, or the holding plate 48 or the like as in the example shown in FIG. You may support from the vacuum vessel 4 around the opening 22. FIG. The pressing plate 48 may be a plurality of partial ones or a ring-like one.

  The bottom surface 31 of the dielectric cup 30 may be configured to be substantially in the same plane as the surface of the surrounding vacuum vessel 4 as in the example shown in FIG. It can be part of it, or it can be protruding somewhat.

  The material of each dielectric cup 30 is, for example, quartz glass, alumina, silicon carbide, silicon nitride, silicon, or other ceramics.

  A gas introduction part 36 for introducing a gas 34 into each dielectric cup 30 is provided. The gas introduction portion 36 may be provided in the portion of the lid 24 as in the example shown in FIG. 3 or the like, or may be provided in the portion of the side surface 32 of the dielectric cup 30 as in the example shown in FIG. good.

The gas 34 may be made in accordance with the processing content applied to the substrate 2. For example, when film formation is performed on the substrate 2 by plasma CVD, the gas 34 is a gas obtained by diluting a source gas with a diluent gas (for example, H ₂ ). More specifically, an Si film is formed on the surface of the substrate 2 when the source gas is SiH _4, an SiN film is formed when SiH ₄ + NH ₃ is used, and an SiO ₂ film is formed when SiH ₄ + O ₂ is used. be able to.

  Each dielectric cup 30 is filled with a dielectric filling 38. That is, the antenna conductor 26 is buried in the filling 38 in the dielectric cup 30. The filling 38 has a gas flow path that guides the gas 34 introduced from the gas introduction part 36 to each small hole 33 on the bottom surface 31 of the dielectric cup 30. This filler 38 is discharged in the space between the antenna conductor 26 and the dielectric cup 30 by electron acceleration by an induced electric field while ensuring the flow path of the gas 34, and plasma is not generated in the dielectric cup 30. It fills closely to the extent. The filler 38 is preferably filled almost completely in the dielectric cup 30. By doing so, it is possible to more reliably prevent plasma from being generated in the dielectric cup 30.

  More specifically, the filling 38 in the examples of FIGS. 3 to 7 is a large number of dielectric grains. In this case, there are small gaps between adjacent dielectric grains, and a plurality of such gaps are connected while being bent to form the gas flow path. The dielectric particles are spherical in the examples of FIGS. 3 to 7, but may be elliptical spheres. In addition, all of the same size of dielectric particles may be used, or two or more types of different sizes of dielectric particles may be used to fill the gaps smaller.

  The filler 38 may be other than a large number of dielectric grains. For example, the filler 38 may be a number of dielectric short tubes as shown in an enlarged view in FIG. In this case, there is a small gap between adjacent dielectric short tubes, and there is also a space in each dielectric short tube, and such a plurality of gaps and spaces are connected to each other while being bent to each other. Forming a road. Two or more different types of dielectric short tubes may be used.

  The filling 38 may be a cotton-like dielectric material such as glass wool. This may be packed in the dielectric cup 30. In this case, a small space exists between adjacent short fiber-like dielectrics, and such a plurality of spaces are connected while being bent to form the gas flow path.

  The material of the filling 38 is the same as that exemplified above as the material of the dielectric cup 30, for example.

  Although the antenna conductor 26 in each antenna opening 22 is covered with the dielectric cup 30 and the dielectric cup 30 is filled with the filler 38, each dielectric cup 30 is Since the plurality of small holes 33 are provided and the filling 38 has the gas flow path as described above and each antenna conductor 26 is not vacuum-sealed from the inside of the vacuum vessel 4, The antenna conductor 26 exists in the vacuum atmosphere in the vacuum vessel 4. Therefore, each antenna conductor 26 basically has a structure arranged in the vacuum vessel 4 and is therefore an internal antenna type.

  Referring again to FIG. 2, the plasma processing apparatus includes a high frequency power supply 50 that supplies high frequency power to each antenna conductor 26 and flows high frequency current to each antenna conductor 26. In this example, the same number of high-frequency power sources 50 as the antenna conductors 26 are provided, and high-frequency power from each high-frequency power source 50 is supplied to one feeding portion 28 (see FIG. 3 and the like) of each antenna conductor 26 via a matching circuit 52. ). The other feeding portion 29 (see FIG. 3 and the like) of each antenna conductor 26 is grounded via the termination capacitor 54 in this example, but may be directly grounded.

  Instead of providing the same number of high-frequency power sources 50 as the antenna conductors 26, one high-frequency power source 50 and a power distributor are provided, and high-frequency power from this power distributor is supplied to each antenna conductor 26 via each matching circuit 52. You may do it.

  The frequency of the high-frequency power output from the high-frequency power supply 50 is, for example, a general 13.56 MHz, but is not limited to this.

  The operation of this plasma processing apparatus will be described. When the gas 34 is introduced into each dielectric cup 30 from the gas introduction portion 36, the gas 34 passes through the gas flow path of the filling 38 in the dielectric cup 30 and is guided to each small hole 33 of the dielectric cup 30. Then, it passes through the small holes 33 and is supplied to the vicinity of the outside of the bottom surface 31 of each dielectric cup 30 (inside the vacuum vessel 4).

  Further, by supplying high frequency power from the high frequency power supply 50 to each antenna conductor 26 and causing a high frequency current to flow, a high frequency magnetic field is generated around each antenna conductor 26, thereby generating an induction electric field around each antenna conductor 26. To do. The high-frequency magnetic field and the induction electric field are also generated near the outside of the bottom surface 31 of the dielectric cup 30 through the dielectric cup 30.

  However, each dielectric cup 30 is filled with a filling 38, and the side surface 32 of each dielectric cup 30 is brought close to the wall surface of the antenna opening 22, and the inside of each dielectric cup 30 and its side Since electrons cannot sufficiently travel in the outer space of the side surface 32, plasma is prevented from being generated, and plasma 46 is generated only near the outer side of the bottom surface 31 of each dielectric cup 30, which becomes a plasma generation region 44.

  That is, the filling 38 in each dielectric cup 30 prevents the electrons from traveling a sufficient distance so that the gas 34 can pass but can maintain the discharge, so that plasma is generated in each dielectric cup 30. Can be prevented.

  Furthermore, the side surface 32 of each dielectric cup 30 is brought close to the wall surface of the antenna opening 22, and electrons travel a sufficient distance to maintain discharge in the space between the wall surface of the antenna opening 22 and the side surface 32. Therefore, it is possible to prevent plasma from being generated in the space.

  Due to the above-described action, plasma generation is prevented in the inner space of each dielectric cup 30 and in the outer space of the side surface 32, and the plasma 46 is generated only in the plasma generation region 44 near the outer side of the bottom surface 31 of each dielectric cup 30. Can be generated. Therefore, the high frequency power for plasma generation can be efficiently supplied to the plasma generated in the plasma generation region 44, so that the high frequency power can be used efficiently.

  The plasma 46 generated in the plasma generation region 44 diffuses and reaches the vicinity of the substrate 2. With this plasma 46, the substrate 2 can be subjected to desired processing such as film formation by CVD, etching, and ashing.

  Moreover, since each plasma generation region 44 is located closer to the substrate 2 than each antenna conductor 26, the plasma 46 generated in each plasma generation region 44 can be efficiently used for processing the substrate 2. . Therefore, for this reason as well, high-frequency power can be used efficiently.

  Further, the gas 34 introduced into each dielectric cup 30 passes through each small hole 33 on the bottom surface 31 of each dielectric cup 30 and is immediately adjacent to each plasma generation region 44 near the outside of the bottom surface 31. Therefore, the gas pressure in each plasma generation region 44 can be locally increased. Therefore, high-density plasma can be generated by each plasma generation region 44, and the supply gas 34 can be used efficiently.

  In addition, since the antenna conductor 26 is provided in the antenna opening 22 provided on the wall surface of the vacuum container 4, when the distance between the antenna conductor and the substrate 2 is made substantially the same, the comparison is made in the vacuum container 64. Compared to the prior art (see FIG. 1) in which the antenna conductor 66 protrudes, the volume of the vacuum vessel 4 can be reduced. Therefore, the exhaust capacity of the vacuum exhaust device 8 for the vacuum vessel 4 can be reduced.

That is, when the distance L ₁ shown in FIG. 1 and the distance L ₃ shown in FIG. 2 are made substantially the same and compared, in the present invention, the wall surface of the vacuum vessel 4 is a distance corresponding to the antenna protruding distance L ₂ in FIG. Can be arranged inside (see FIG. 2), the volume of the vacuum vessel 4 can be reduced by an amount equivalent to the distance L ₂ converted into a volume.

More specifically, the distance L ₁ in the prior art shown in FIG. 1 is about 200 mm to about 300 mm, whereas the distance L ₂ is about 100 mm. According to the present invention, the distance L ₁ is Since the corresponding distance can be eliminated, the distance between the substrate 2 and the inner wall of the vacuum vessel 4 can be shortened to about 2/3 to about 3/4 of the prior art, and the vacuum vessel accordingly. The volume of 4 can be reduced. As a result, the exhaust capacity of the vacuum exhaust device 8 can be reduced.

  Further, when a film is formed using plasma as in plasma CVD, unnecessary film deposition occurs on the surface of the antenna 70 protruding into the vacuum container 64 in the conventional technique as shown in FIG. While it may contaminate the substrate 2 as a dust generation source, in the present invention, since the antenna does not protrude into the vacuum container 4, unnecessary film deposition and accompanying dust generation can be reduced. it can. As a result, the maintenance frequency of the apparatus can be reduced.

The distance L ₄ (see FIGS. 3 and 4) between the side surface 32 of each dielectric cup 30 and the wall surface of the antenna opening 22 is preferably in the range of 0 mm to 5 mm. This is because the gas pressure in the space during operation of the plasma processing apparatus is, for example, about 0.7 Pa to 133 Pa, and considering the mean free path of electrons in such a gas pressure atmosphere, 5 mm is the average. This is because, since it is sufficiently smaller than the free stroke, electrons cannot travel a sufficient distance to ionize the gas in the space, and thus no plasma is generated.

  The antenna conductor 26 has a coil shape as in the above example, for example. In this case, by increasing the number of turns, an induced electric field can be generated more strongly, so that a plasma 46 with a higher density can be generated. However, when the number of turns of the antenna conductor 26 is increased, the impedance is increased, so that a large potential is generated on the power feeding side. From this point of view, the number of turns of the coiled antenna conductor 26 is preferably about 1 to 2 turns, for example. The examples shown in FIGS. 2 to 7 and 9 are examples of 1.5 turns.

  The coiled antenna conductor 26 may be wound such that the front surface portion 27 is substantially parallel to the bottom surface 31 of the dielectric cup 30, as in the example shown in FIG. 9, for example. By doing so, it is expected that the plasma generation region 44 can generate an induced electric field more uniformly than the antenna conductor 26 shown in FIG.

  The antenna conductor 26 may have a spiral shape as in the example shown in FIG. In this case, since the antenna conductor 26 can be wound widely and uniformly, it is possible to generate plasma with better in-plane spread and uniformity compared to the coil shape. Further, by increasing the number of turns, an induced electric field can be generated more strongly, and a higher density plasma can be generated.

  The antenna conductor 26 may have a rod shape (straight bar shape) as in the example shown in FIG. As a result, linear plasma can be generated. FIG. 11 shows an example in which two lines are arranged in parallel. Alternatively, the antenna conductor 26 may be planar as in the example shown in FIG. Thereby, planar plasma can be generated. Further, since the rod-like or planar antenna conductor 26 has low impedance, the plasma potential can be lowered.

  FIG. 1 shows an example in which a plurality of antenna openings 22 and antenna portions 20 are arranged on the ceiling surface 6 of the vacuum vessel 4 facing the processing surface of the substrate 2, but the present invention is not limited thereto. For example, the plurality of antenna openings 22 and the antenna unit 20 may be arranged so as to surround the substrate 2 on the side surface of the vacuum vessel 4, or both (the ceiling surface arrangement and the side arrangement) may be used in combination. Further, one antenna opening 22 and one antenna unit 20 may be provided according to the dimensions of the substrate 2 and the like.

DESCRIPTION OF SYMBOLS 2 Substrate 4 Vacuum container 10 Holder 20 Antenna part 22 Antenna opening 24 Lid 26 Antenna conductor 30 Dielectric cup 31 Bottom face 32 Side face 33 Small hole 34 Gas 36 Gas introduction part 38 Filling 44 Plasma generation area 46 Plasma 50 High frequency power supply

Claims (4)

An inductively coupled and internal antenna type plasma in which a plasma is generated by ionizing a gas by an induced electric field generated by flowing a high frequency current through an antenna conductor provided in a vacuum vessel, and the substrate is processed using the plasma. A processing device comprising:
A holder that is provided in the vacuum vessel and holds the substrate;
One or more antenna openings provided on the wall of the vacuum vessel;
A lid that covers the outer surface of the vacuum container of each antenna opening;
The antenna conductor provided in each antenna opening;
A bottom surface located on the holder side, a side surface connected to the bottom surface, and a plurality of small holes provided in the bottom surface, covering each antenna conductor in each antenna opening; and Dielectric cups provided so that side surfaces are close to the wall surface of the antenna opening,
A gas introduction part for introducing the gas into each dielectric cup;
Filling each dielectric cup and having a gas flow path for guiding the gas introduced from the gas introduction part to each small hole on the bottom surface of the dielectric cup. Things,
A plasma processing apparatus, comprising: a high-frequency power source that supplies high-frequency power to each antenna conductor and causes the high-frequency current to flow through each antenna conductor.   The plasma processing apparatus according to claim 1, wherein a distance between a side surface of the dielectric cup and a wall surface of the antenna opening in which the dielectric cup is accommodated is set to 0 mm to 5 mm.   The plasma processing apparatus according to claim 1, wherein the filler is a large number of dielectric particles.   The plasma processing apparatus according to claim 1, wherein the filling is a plurality of dielectric short tubes.

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