JP2010170974A - Plasma source and plasma treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma source and a plasma treatment device wherein the correction of plasma distribution can be carried out easily. <P>SOLUTION: The plasma source 2 is equipped with a micro-wave forming mechanism 30 that forms micro-waves, a plurality of antennae modules 41 that introduce the formed micro-waves into a chamber 1, and a micro-wave synthesis part 70 installed neighboring the chamber 1 to synthesize the micro-waves radiated from the plurality of antennae modules 41. The micro-wave synthesis part 70 has a synthesizing space 74 to space-synthesize the microwaves radiated from the plurality of antennae modules 41, and a dielectric member 72 installed between the synthesizing space 74 and the chamber 1. The micro-waves synthesized in the synthesizing space 74 are introduced into the chamber 1 via the dielectric member 72. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plasma source that introduces electromagnetic waves into a processing vessel for performing plasma processing, and converts the gas supplied into the processing vessel into plasma, and a plasma processing apparatus using such a plasma source.

  Plasma processing is an indispensable technology for the manufacture of semiconductor devices. Recently, the design rules of semiconductor elements constituting LSIs have been increasingly miniaturized due to the demand for higher integration and higher speed of LSIs, and semiconductor wafers Along with this, there is a demand for plasma processing apparatuses that can cope with such miniaturization and enlargement.

  However, in parallel plate type and inductively coupled plasma processing apparatuses that have been widely used in the past, the electron temperature is high, resulting in plasma damage to the microelements, and because the region where the plasma density is high is limited, it is large. It is difficult to uniformly and rapidly plasma-treat the semiconductor wafer.

Therefore, RLSA (Radial Line) that can form a high density and low electron temperature plasma uniformly.
(Slot Antenna) A microwave plasma processing apparatus has attracted attention (for example, Patent Document 1).

  The RLSA microwave plasma processing apparatus is provided with a planar antenna (Radial Line Slot Antenna) in which a number of slots are formed in a predetermined pattern at the upper part of the chamber, and the microwave guided from the microwave generation source is transmitted to the slot of the planar antenna. And radiates into a chamber held in a vacuum through a microwave transmission plate made of a dielectric material provided below, and this microwave electric field converts the gas introduced into the chamber into plasma, An object to be processed such as a semiconductor wafer is processed by the plasma thus formed.

  In such an RLSA microwave plasma apparatus, when adjusting the plasma distribution, it is necessary to prepare a plurality of antennas having different slot shapes, patterns, etc., and to exchange the antennas, which is extremely complicated.

  On the other hand, Patent Document 2 discloses a microwave plasma source that divides microwaves into a plurality of components, radiates the microwaves into the chamber through a plurality of antenna modules, and synthesizes the microwaves in the chamber space. ing.

  Thus, by spatially synthesizing microwaves using a plurality of antenna modules, the plasma distribution can be adjusted by adjusting the phase and intensity of the microwaves radiated from the antennas of the respective antenna modules.

JP 2000-294550 A International Publication No. 2008/013112 Pamphlet

  However, in the technique disclosed in Patent Document 2, when the plasma density in the chamber is high, microwaves (electromagnetic waves) radiated from the antennas of the respective antenna modules cannot pass through the plasma, and the plasma immediately below the antennas is converted. There is a possibility that the microwaves radiated from the respective antennas cannot be sufficiently synthesized and the plasma distribution cannot be sufficiently adjusted.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a plasma source and a plasma processing apparatus capable of easily adjusting a plasma distribution.

  In order to solve the above-mentioned problems, according to a first aspect of the present invention, there is provided a plasma source for introducing an electromagnetic wave into a processing vessel for performing a plasma treatment and converting the gas supplied into the processing vessel into a plasma. An electromagnetic wave generation mechanism for generating the electromagnetic wave, a plurality of antenna modules for introducing the generated electromagnetic wave into the processing container, and an electromagnetic wave provided adjacent to the processing container and combining the electromagnetic waves radiated from the plurality of antenna modules The electromagnetic wave synthesizer has a synthetic space for spatially synthesizing the electromagnetic waves radiated from the plurality of antenna modules, and a dielectric member provided between the synthetic space and the chamber. The plasma source is characterized in that the electromagnetic wave synthesized in the synthesis space is introduced into the processing container through the dielectric member.

  In the first aspect, the composite space is preferably a free space having a dielectric constant of 1.0. In this case, the height of the synthetic space is preferably 1/12 or more of the wavelength of the electromagnetic wave, and the pressure of the synthetic space is 200 Torr (26660 Pa) or more or 0.1 mTorr (0.0133 Pa) or less. It is preferable. The pressure in the synthesis space is more preferably atmospheric pressure.

  According to a second aspect of the present invention, there is provided a plasma source for introducing an electromagnetic wave into a processing vessel for performing plasma processing and converting the gas supplied into the processing vessel into a plasma, and an electromagnetic wave generating mechanism for generating the electromagnetic wave; A plurality of antenna modules for introducing the generated electromagnetic waves into the processing container, and an electromagnetic wave synthesis unit that is provided adjacent to the processing container and synthesizes the electromagnetic waves radiated from the plurality of antenna modules, The electromagnetic wave synthesizing unit has a synthetic dielectric member made of a dielectric that synthesizes electromagnetic waves radiated from the plurality of antenna modules, and introduces the electromagnetic wave synthesized in the synthetic dielectric member into the processing container. A plasma source is provided.

  In the second aspect, the synthetic dielectric member preferably has a thickness of λg / 12 or more, where λg is the effective wavelength of the microwaves therein. The synthetic dielectric member is preferably made of quartz or ceramics.

  In the first and second aspects, it is preferable to further include plasma ignition means for igniting plasma in the processing container. In this case, the plasma ignition means may include an ignition antenna module that guides electromagnetic waves to the processing container via the dielectric member without passing through the synthetic space. The ignition antenna module preferably induces an electric field in the processing container through a central portion of the dielectric member. The plasma ignition means may include a direct current ignition source provided in the processing container.

  Furthermore, in the first and second aspects, the electromagnetic wave pattern adjusting means for adjusting the plasma distribution by adjusting the pattern of the electromagnetic wave synthesized by the electromagnetic wave synthesizing unit may be further provided. In this case, the electromagnetic wave pattern adjusting means may be provided in each antenna module, and may include a phase shifter that adjusts the phase of the electromagnetic wave radiated from each antenna module, and is provided in each antenna module. Also, an amplifier for adjusting the power of the electromagnetic wave radiated from each antenna module can be provided. These may be used in combination.

  Furthermore, in each of the first and second aspects, each of the antenna modules is provided in a cylindrical main body container and coaxially within the main body container, and an electromagnetic wave transmission path is formed between the main body container and the antenna module. A cylindrical or rod-shaped inner conductor, a tuner for adjusting impedance in the electromagnetic wave transmission path, and an antenna unit having an electromagnetic wave radiation antenna for radiating the electromagnetic wave transmitted through the electromagnetic wave transmission path into the processing container. Further, an electromagnetic wave introduction mechanism can be provided.

  In a third aspect of the present invention, a processing container that accommodates a substrate to be processed, a mounting table on which the substrate to be processed is placed in the processing container, a gas supply mechanism that supplies gas into the processing container, There is provided a plasma processing apparatus comprising: the plasma source according to the first aspect, wherein a processing target substrate in the processing container is processed by plasma.

  In the third aspect, the mounting table may further include a high-frequency bias application mechanism that applies high-frequency bias power for ion attraction.

  According to the present invention, an electromagnetic wave synthesizing unit that synthesizes electromagnetic waves radiated from the plurality of antenna modules is used that has a synthetic space provided separately from the processing container. The synthesized electromagnetic wave is synthesized by spatially synthesizing the radiated electromagnetic wave, and the synthesized electromagnetic wave is introduced into a processing container that forms plasma through the dielectric member, or a synthetic dielectric member made of a dielectric is used as the electromagnetic wave synthesizer. The composite dielectric member is used to synthesize electromagnetic waves radiated from a plurality of antenna modules, and the synthesized electromagnetic waves are introduced into the processing container. It is not disturbed by the plasma inside. Therefore, the synthetic electromagnetic wave pattern can be adjusted in advance by adjusting one or both of the phase and electric power of the electromagnetic wave radiated from each antenna module, and this synthetic electromagnetic wave pattern can be adjusted via the dielectric member. Since it is transferred to the inner plasma, the plasma distribution can be adjusted.

It is sectional drawing which shows schematic structure of the plasma processing apparatus by which the plasma source which concerns on one Embodiment of this invention is mounted. It is a block diagram which shows the structure of the plasma source of FIG. It is a top view which shows typically the antenna unit in the plasma source of FIG. It is a figure which shows the example of the circuit structure of the main amplifier used for the antenna module in the plasma source of FIG. It is sectional drawing which shows the microwave introduction mechanism used for the antenna module in the microwave plasma source of FIG. It is a top view which shows the preferable form of a planar slot antenna. It is a perspective view which shows the antenna part which has a square-shaped top plate. It is sectional drawing which shows the principal part of the microwave plasma source of the plasma processing apparatus of FIG. It is sectional drawing which shows the principal part of the plasma source which concerns on the 2nd Embodiment of this invention. It is a top view which shows typically the antenna unit in the plasma source of FIG. It is sectional drawing which shows schematic structure of the plasma processing apparatus by which the plasma source which concerns on the 3rd Embodiment of this invention is mounted. It is sectional drawing which shows the principal part of the microwave plasma source of the plasma processing apparatus of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, a plasma source and a plasma processing apparatus using microwaves as electromagnetic waves will be described.

<First Embodiment>
(Configuration of plasma processing apparatus equipped with the plasma source according to the first embodiment)
FIG. 1 is a sectional view showing a schematic configuration of a plasma processing apparatus equipped with a plasma source according to a first embodiment of the present invention, FIG. 2 is a configuration diagram showing the configuration of the plasma source of FIG. 1, and FIG. 4 is a plan view schematically showing an antenna unit in one plasma source, FIG. 4 is a diagram showing an example of a circuit configuration of a main amplifier used in the antenna module in the plasma source in FIG. 1, and FIG. 5 is a microwave plasma source in FIG. It is sectional drawing which shows the microwave introduction mechanism used for the antenna module in FIG.

  The plasma processing apparatus 100 is configured as a plasma etching apparatus that performs, for example, an etching process on a wafer, and is a substantially cylindrical grounded chamber made of a metal material such as aluminum or stainless steel that is hermetically configured. 1 and a microwave plasma source 2 for forming microwave plasma in the chamber 1. An opening 1 a is formed in the upper part of the chamber 1, and the microwave plasma source 2 is provided so as to face the inside of the chamber 1 from the opening 1 a.

  In the chamber 1, a susceptor 11 for horizontally supporting a wafer W as an object to be processed is supported by a cylindrical support member 12 erected at the center of the bottom of the chamber 1 via an insulating member 12 a. Is provided. Examples of the material constituting the susceptor 11 and the support member 12 include aluminum whose surface is anodized (anodized).

  Although not shown, the susceptor 11 includes an electrostatic chuck for electrostatically attracting the wafer W, a temperature control mechanism, a gas flow path for supplying heat transfer gas to the back surface of the wafer W, and the wafer. In order to convey W, elevating pins and the like that elevate and lower are provided. Furthermore, a high frequency bias power supply 14 is electrically connected to the susceptor 11 via a matching unit 13. By supplying high frequency power from the high frequency bias power source 14 to the susceptor 11, ions are attracted to the wafer W side.

  An exhaust pipe 15 is connected to the bottom of the chamber 1, and an exhaust device 16 including a vacuum pump is connected to the exhaust pipe 15. Then, by operating the exhaust device 16, the inside of the chamber 1 is exhausted, and the inside of the chamber 1 can be decompressed at a high speed to a predetermined degree of vacuum. Further, on the side wall of the chamber 1, a loading / unloading port 17 for loading / unloading the wafer W and a gate valve 18 for opening / closing the loading / unloading port 17 are provided.

  A shower plate 20 that discharges a processing gas for plasma etching toward the wafer W is horizontally provided above the susceptor 11 in the chamber 1. The shower plate 20 has a gas flow path 21 formed in a lattice shape and a large number of gas discharge holes 22 formed in the gas flow path 21. It is a space part 23. A pipe 24 extending outside the chamber 1 is connected to the gas flow path 21 of the shower plate 20, and a processing gas supply source 25 is connected to the pipe 24.

  On the other hand, a ring-shaped plasma gas introduction member 26 is provided along the chamber wall above the shower plate 20 of the chamber 1, and the plasma gas introduction member 26 has a number of gas discharge holes on the inner periphery. Is provided. A plasma gas supply source 27 for supplying plasma gas is connected to the plasma gas introduction member 26 via a pipe 28. As the plasma gas, a rare gas such as Ar gas is preferably used.

  The plasma gas introduced into the chamber 1 from the plasma gas introduction member 26 is turned into plasma by the microwave introduced into the chamber 1 from the microwave plasma source 2, and this Ar plasma passes through the space 23 of the shower plate 20. Then, the processing gas discharged from the gas discharge holes 22 of the shower plate 20 is excited to form plasma of the processing gas.

  The microwave plasma source 2 is supported by a support ring 29 provided at the upper portion of the chamber 1, and the space between them is hermetically sealed. As shown in FIG. 2, the microwave plasma source 2 includes a microwave output unit 30 that outputs a microwave distributed to a plurality of paths, and a plurality of microwaves that radiate the microwave output from the microwave output unit 30. The antenna unit 40 includes the antenna modules 41 and the microwave synthesis unit 70 that synthesizes the microwaves radiated from the antenna modules 41.

  The microwave output unit 30 includes a power supply unit 31, a microwave oscillator 32, an amplifier 33 that amplifies the oscillated microwave, and a distributor 34 that distributes the amplified microwave into a plurality of parts.

  The microwave oscillator 32 causes, for example, a PLL oscillation of a microwave having a predetermined frequency (for example, 2.45 GHz). The distributor 34 distributes the microwave amplified by the amplifier 33 while matching the impedance between the input side and the output side so that the loss of the microwave does not occur as much as possible. In addition to the 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz, or the like can be used as the microwave frequency.

The antenna unit 40 includes a plurality of antenna modules 41 that guide the microwaves distributed by the distributor 34. Each antenna module 41 includes an amplifier unit 42 that mainly amplifies the distributed microwave and a microwave introduction mechanism 43. The microwave introduction mechanism 43 includes a tuner 44 for matching impedance and an antenna unit 45 that radiates the amplified microwave into the chamber 1. A microwave is radiated from the antenna portion 45 of the microwave introduction mechanism 43 in each antenna module 41. As shown in FIG. 3, the antenna unit 40 has eight antenna modules 41, and the microwave introduction mechanism 43 of each antenna module 41 is placed on an upper dielectric plate 71 (to be described later) of the microwave synthesizer 70. Are arranged circumferentially at equal intervals.
The number of antenna modules 41 and the arrangement of the microwave introduction mechanisms 43 are not limited to the present embodiment.

  The amplifier unit 42 includes a phase shifter 46, a variable gain amplifier 47, a main amplifier 48 constituting a solid state amplifier, and an isolator 49.

  The phase shifter 46 is configured so that the phase of the microwave can be changed by the slag tuner, and the radiation characteristic can be modulated by adjusting this. For example, the plasma distribution can be changed by controlling the directivity by adjusting the phase for each antenna module.

  The variable gain amplifier 47 is an amplifier for adjusting the power level of the microwave input to the main amplifier 48, adjusting the variation of individual antenna modules, or adjusting the plasma intensity. By changing the variable gain amplifier 47 for each antenna module, the generated plasma can be distributed.

  For example, as shown in FIG. 4, the main amplifier 48 constituting the solid-state amplifier has an input matching circuit 61, a semiconductor amplifying element 62, an output matching circuit 63, and a high-Q resonance circuit 64. Can do. As the semiconductor amplifying element 62, GaAs HEMT, GaN HEMT, and LD (Laterally Diffused) -MOS capable of class E operation can be used. In particular, when a GaN HEMT is used as the semiconductor amplifying element 62, the variable gain amplifier 47 has a constant value, the power supply voltage of the class E operation amplifier is variable, and power control is performed.

  The isolator 49 separates the reflected microwaves reflected by the antenna unit 45 and directed to the main amplifier 48, and includes a circulator and a dummy load (coaxial terminator). The circulator guides the microwave reflected by the antenna unit 45 to the dummy load, and the dummy load converts the reflected microwave guided by the circulator into heat.

  In this embodiment, a plurality of antenna modules 41 are provided, and the microwaves radiated from the microwave introduction mechanism 43 of each antenna module are spatially synthesized. Therefore, the isolator 49 may be small and provided adjacent to the main amplifier 48. It is possible.

  The microwave introduction mechanism 43 has a main body container 50 as shown in FIG. The antenna unit 45 is disposed at the distal end portion of the main body container 50, and a portion closer to the base end side than the antenna unit 45 of the main body container 50 is an impedance adjustment range by the tuner 44. The main body container 50 is made of metal and has a cylindrical shape, and constitutes an outer conductor of a coaxial tube. An inner conductor 52 of a coaxial tube extends vertically in the main body container 50. The inner conductor 52 is formed in a rod shape or a cylindrical shape. A microwave transmission path is formed between the main body container 50 and the inner conductor 52.

  The antenna unit 45 has a planar slot antenna 51 that is planar and has a slot 51 a, and the inner conductor 52 is connected to the center of the planar slot antenna 51.

  A power supply conversion unit (not shown) is attached to the base end side of the main body container 50. The power supply conversion unit is connected to the main amplifier 48 via a coaxial cable, and an isolator 49 is interposed in the middle of the coaxial cable. Yes. The main amplifier 48 is a power amplifier and handles high power, so it operates with high efficiency such as class E, but its heat is equivalent to several tens to several hundreds of watts, so it is attached in series to the antenna unit 45 from the viewpoint of heat dissipation. To do.

  The antenna unit 45 includes a slow wave material 55 provided on the upper surface of the planar slot antenna 51. The slow wave material 55 has a dielectric constant larger than that of a vacuum, and is made of a dielectric material such as a fluororesin such as quartz, ceramics, polytetrafluoroethylene, or a polyimide resin, and is in a vacuum. It has a function of adjusting the plasma by making the wavelength shorter than the wavelength of the microwave. The slow wave material 55 can adjust the phase of the microwave depending on the thickness thereof, and the thickness thereof is adjusted so that the planar slot antenna 51 becomes a “wave” of a standing wave. Thereby, reflection can be minimized and the radiation energy of the planar slot antenna 51 can be maximized.

  A dielectric member for vacuum sealing, for example, a top plate 56 made of quartz or ceramics is disposed on the lower surface of the planar slot antenna 51. Then, the microwave amplified by the main amplifier 48 passes between the inner conductor 52 and the peripheral wall of the main body container 50, passes through the top plate 56 from the slot 51 a of the planar slot antenna 51, and further, the upper dielectric of the microwave synthesis unit 70. The light passes through the body plate 71 and is radiated to the composite space 74. The microwave radiated from the planar slot antenna 51 may be directly transmitted through the lower dielectric plate 72 without providing the top plate 56. In this case, a stronger electric field can be induced in the chamber 1.

  For example, as shown in FIG. 6, four slots 51a are equally formed in the shape of a divided arc. As a result, a substantially uniform slot 51a is formed in the circumferential direction, so that the propagated microwave is suppressed from being reflected by the planar slot antenna 51, and the mismatch region is reduced or substantially eliminated. Can do. The slot 51a is preferably fan-shaped because the length of the slot 51a can be reduced and the slot 51a can be made compact. Further, as shown in FIG. 7, the top plate 56 preferably has a square shape (cuboid) or a round shape (column) having a diameter larger than that of the main body container 50. Thereby, a microwave can be efficiently radiated in the TE mode.

  As shown in FIG. 5, the tuner 44 has two slags 58 in a portion closer to the base end side than the antenna portion 45 of the main body container 50, and constitutes a slag tuner. The slug 58 is configured as a plate-like body made of a dielectric, and is provided in an annular shape between the inner conductor 52 and the outer wall of the main body container 50. The impedance is adjusted by moving the slugs 58 up and down by an actuator 59 based on a command from the controller 60. The controller 60 performs impedance adjustment so that the termination is, for example, 50Ω. If only one of the two slugs 58 that is closer to the top plate 56 is moved, a circular locus passing through the origin of the Smith chart is drawn, and if both are moved simultaneously, only the phase of the reflection coefficient is rotated.

  In the present embodiment, the main amplifier 48, the tuner 44, and the planar slot antenna 51 are arranged close to each other. The tuner 44 and the planar slot antenna 51 constitute a lumped constant circuit existing within a half wavelength, and these function as a resonator.

  As shown in FIG. 8, the microwave synthesis unit 70 includes a disk-shaped upper dielectric plate 71 that supports the antenna units 45 of the plurality of microwave introduction mechanisms 43, and an upper dielectric plate 71 below the upper dielectric plate 71. A lower dielectric plate 72 in the form of a disk provided facing the dielectric plate 71 at an appropriate distance and a metal provided along the outer periphery between the upper dielectric plate 71 and the lower dielectric plate 72 The upper dielectric plate 71, the lower dielectric plate 72, and the spacer member 73 define a synthetic space 74 that is a free space (a space having a relative dielectric constant of 1.0). Yes. Microwaves radiated from the antenna portions 45 of the plurality of microwave introduction mechanisms 43 are introduced into the synthesis space 74 through the upper dielectric plate 71, and these microwaves are synthesized and synthesized in the synthesis space 74. The microwave is radiated into the chamber 1 from the opening 1a through the lower dielectric plate 73. A seal ring 29 a is interposed between the lower dielectric plate 73 and the support ring 29.

As the upper dielectric plate 71 and the lower dielectric plate 72, for example, a dielectric such as quartz, ceramics, or resin is used. The upper dielectric plate 71 does not need to have plasma resistance because it is not exposed to plasma. However, since the lower dielectric plate 72 is exposed to plasma in the chamber 1, a material having plasma resistance such as quartz is used. It is preferable to use Y ₂ O ₃ ceramics.

  The height of the synthesis space 74 needs to be high enough to synthesize microwaves radiated from the antenna portions 45 of the plurality of microwave introduction mechanisms 43, and is preferably 1/12 wavelength or more. . Further, the synthesis space 74 needs to have a pressure that does not cause an abnormal discharge that hinders the microwave synthesis. Based on Paschen's law, the synthesis space 74 has a high pressure of 200 Torr (26660 Pa) or higher. A low pressure of 1 mTorr (0.0133 Pa) or less is preferable. From the viewpoint of simplicity, atmospheric pressure is preferable.

  Each component in the plasma processing apparatus 100 is controlled by a control unit 80 including a microprocessor. The control unit 80 includes a storage unit that stores a process recipe, an input unit, a display, and the like, and controls the plasma processing apparatus in accordance with the selected recipe.

(Operation, action, and effect of plasma processing apparatus equipped with plasma source according to first embodiment)
Next, the operation of the plasma processing apparatus configured as described above will be described.
First, the wafer W is loaded into the chamber 1 and placed on the susceptor 11. Then, a microwave is introduced into the chamber 1 from the microwave plasma source 2 while a plasma gas, for example, Ar gas, is introduced into the chamber 1 from the plasma gas supply source 27 through the pipe 28 and the plasma gas introduction member 26. A plasma is formed.

Next, a processing gas, for example, an etching gas such as Cl ₂ gas is discharged from the processing gas supply source 25 into the chamber 1 through the pipe 24 and the shower plate 20. The discharged processing gas is excited and converted into plasma by the plasma passing through the space 23 of the shower plate 20, and plasma processing, for example, etching processing is performed on the wafer W by the plasma of the processing gas thus formed. .

  Here, in the microwave plasma source 2, the microwave oscillated from the microwave oscillator 32 of the microwave output unit 30 is amplified by the amplifier 33 and then distributed into a plurality of parts by the distributor 34. The antenna unit 40 guides the plurality of antenna modules 41. In the antenna module 41, the microwaves distributed in this way are individually amplified by the main amplifier 48 constituting the solid-state amplifier, passed through the microwave transmission path 53 of the microwave introduction mechanism 43, and the planar slot antenna. 51 individually radiated, transmitted through the upper dielectric plate 71 of the microwave synthesizer 70 and introduced into the synthesis space 74, in which these microwaves are synthesized. The microwave after being synthesized in the synthesis space 74 passes through the lower dielectric plate 72 and is introduced into the chamber 1.

  In this case, since the synthesis space 74 is provided separately from the chamber 1, no plasma is formed in the synthesis space 74. Therefore, the microwave (electromagnetic wave) radiated from the planar slot antenna 51 of each microwave introduction mechanism 43 is spatially synthesized without being disturbed by the plasma (regardless of the plasma state). Therefore, the synthesized microwave (electromagnetic wave) pattern is adjusted in advance by adjusting one or both of the phase and power of the microwave (electromagnetic wave) radiated from the planar slot antenna 51 of each microwave introducing mechanism 43. Since this synthetic microwave (electromagnetic wave) pattern is transferred to the plasma in the chamber 1 through the lower dielectric plate 72, the plasma distribution can be adjusted.

  The adjustment of the synthesized microwave (electromagnetic wave) pattern at this time can be performed by controlling the directivity by adjusting the phase for each antenna module by the phase shifter 46 of each antenna module 41. Further, it can be performed by adjusting the power power for each antenna module by the variable gain amplifier 47 or the main amplifier 48 of each antenna module 41. These may be used in combination. By doing in this way, a microwave pattern can be adjusted according to a use, and thereby plasma distribution can be adjusted and desired plasma distribution can be obtained. For example, the plasma distribution can be made uniform, whereby uniform plasma processing, for example, plasma etching can be performed.

<Second Embodiment>
(Configuration of Plasma Source According to Second Embodiment)
Next, a second embodiment of the present invention will be described.
In the above embodiment, since the microwave (electromagnetic wave) synthesized in the synthesis space is introduced into the chamber 1 that is the plasma generation space via the lower dielectric plate 72, an electric field having a sufficient strength for ignition of plasma in the chamber 1. May not be supplied. Therefore, in order to eliminate such inconvenience, in another embodiment of the present invention, an ignition antenna module is provided.

  FIG. 9 is a cross-sectional view showing the main part of the microwave plasma source according to the second embodiment of the present invention, and FIG. 10 is a plan view showing the arrangement of the antenna module.

  In these drawings, the same components as those in the previous embodiment are denoted by the same reference numerals and description thereof is omitted.

  As shown in these drawings, unlike the first embodiment, this embodiment includes an antenna unit 40 ′ having a plurality (eight in the figure) of antenna modules 41 and an ignition antenna module 41 ′. ing. The ignition antenna module 41 ′ is provided at the center of the upper dielectric plate 71 of the microwave synthesizer 70. The amplifier unit 42 having the same configuration as the antenna module 41 and the microwave introduction mechanism of the antenna module 41 are provided. 43 has a microwave introduction mechanism 43 ′ having a different configuration.

  As shown in FIG. 9, the microwave introduction mechanism 43 ′ of the ignition antenna module 41 ′ has an antenna portion 45 ′ disposed at the distal end portion of the main body container 50, and is proximal to the antenna portion 45 ′ of the main body container 50. Is the tuner 44 '. The tuner 44 ′ is configured similarly to the tuner 44.

  Like the antenna unit 45, the antenna unit 45 'includes a planar slot antenna 51 and a slow wave member 55, but the top plate 56 is omitted. The microwave introduction mechanism 43 ′ is provided so as to penetrate downward through the upper dielectric plate 71 of the microwave synthesizer 70, and the planar slot antenna 51 of the antenna unit 45 ′ is the lower dielectric of the microwave synthesizer 70. It is provided in direct contact with the center of the plate 72.

(Operation / Effect of Plasma Source According to Second Embodiment)
Thus, in the antenna portion 45 ′ of the ignition antenna module 41 ′, the microwave radiated from the planar slot antenna 51 is introduced into the chamber 1 through the lower dielectric plate 72 without passing through the synthesis space 74. Therefore, a strong electric field can be induced in the chamber 1, and plasma can be formed by microwaves (electromagnetic waves) radiated from the antenna module 41 on the outer periphery using the strong electric field as a seed. At this time, the ignition antenna module 41 ′ penetrates the central portion of the upper dielectric plate 71 and reaches the central portion of the lower dielectric plate 72, so that a strong electric field can be induced in the central portion of the chamber 1. .

  The position of the ignition antenna module 41 'is not limited to the central portion, but by providing it in the central portion, plasma ignition can be performed more easily.

  When the ignition antenna module 41 ′ is used, it is preferable to turn on the ignition antenna module 41 ′ during ignition and to turn it off during plasma processing. The antenna module 41 used for plasma processing may be ON or OFF when ignited.

  Further, instead of the ignition antenna module 41 ', other plasma ignition means may be provided. For example, a DC ignition source may be provided in the chamber 1 and plasma may be ignited in the chamber 1 by applying a voltage to the DC ignition source.

<Third Embodiment>
(Configuration of plasma processing apparatus equipped with a plasma source according to the third embodiment)
FIG. 11 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus equipped with a plasma source according to a third embodiment of the present invention, and FIG. 12 is a cross-sectional view showing a main part of the plasma source according to the third embodiment of the present invention. FIG.

  As shown in these drawings, in the present embodiment, instead of the microwave synthesizer 70 in the first embodiment, the microwave synthesis includes a synthetic dielectric member 76 having a thickness capable of microwave synthesis inside. It differs from the first embodiment only in that it includes a portion 70 '.

  The synthetic dielectric member 76 of the microwave synthesis unit 70 ′ has a disk shape, and the antenna units 45 of the plurality of microwave introduction mechanisms 43 are supported by the synthetic dielectric member 76. Then, the microwaves radiated from the antenna unit 45 are introduced into the synthetic dielectric member 76, and the microwaves are synthesized in the synthetic dielectric member 76, and the synthesized microwaves are passed through the opening 1a into the chamber 1. Is supposed to be emitted.

The dielectric constant of the synthetic dielectric member 76 is not limited, but since it is exposed to the plasma in the chamber, it is preferable to use a plasma-resistant material, for example, a ceramic such as quartz or Y ₂ O _3. .

The synthetic dielectric member 76 needs to have a thickness capable of synthesizing the microwaves radiated from the antenna portions 45 of the plurality of microwave introduction mechanisms 43, and the effective microwaves in the synthetic dielectric member 76 are required. When the wavelength is λg, the thickness of the synthetic dielectric member 76 is preferably λg / 12 or more. When the free space wavelength of the microwave is λ and the dielectric constant of the synthetic dielectric member 76 is ε, λg is
λg = λ / ε ^1/2
It is represented by When the material of the synthetic dielectric member 76 is quartz (dielectric constant = 3.88), since λg is 12 cm, the value of λg / 12 is 13.3 mm.

(Operation and Effect of Plasma Source According to Third Embodiment)
In the microwave plasma source of the present embodiment, the microwave oscillated from the microwave oscillator 32 of the microwave output unit 30 is amplified by the amplifier 33 and then distributed to a plurality of parts by the distributor 34. Are guided to a plurality of antenna modules 41 in the antenna unit 40. In the antenna module 41, the microwaves distributed in this way are individually amplified by the main amplifier 48 constituting the solid-state amplifier, passed through the microwave transmission path 53 of the microwave introduction mechanism 43, and the planar slot antenna. The microwaves are individually radiated from 51 and synthesized in the composite dielectric member 76 constituting the microwave synthesis unit 70 ′. The microwaves synthesized in the synthetic dielectric member 76 are introduced into the chamber 1 from the synthetic dielectric member 76.

  Also in this embodiment, the microwaves radiated from the planar slot antenna 51 of each microwave introduction mechanism 43 are not synthesized in the chamber 1 where the plasma is formed, but are synthesized in the synthetic dielectric member 76. (Electromagnetic wave) is synthesized without being disturbed by plasma (regardless of plasma state). Therefore, similarly to the first embodiment, the synthesized microwave is adjusted in advance by adjusting one or both of the phase and power of the microwave (electromagnetic wave) radiated from the planar slot antenna 51 of each microwave introduction mechanism 43. The (electromagnetic wave) pattern can be adjusted, and this synthetic microwave (electromagnetic wave) pattern is transferred to the plasma in the chamber 1 via the synthetic dielectric member 76, so that the plasma distribution can be adjusted.

  The adjustment of the synthetic microwave (electromagnetic wave) pattern at this time is performed by adjusting the phase for each antenna module and controlling the directivity by the phase shifter 46 of each antenna module 41 as in the first embodiment. Alternatively, the power gain can be adjusted for each antenna module by the variable gain amplifier 47 or the main amplifier 48 of each antenna module 41, or these can be used in combination. As in the first embodiment, this makes it possible to adjust the plasma pattern by adjusting the microwave pattern according to the application, and obtain a desired plasma distribution.

  Further, in the present embodiment, since it is only necessary to provide the plate-shaped synthetic dielectric member 76 in the microwave synthesizing unit, the apparatus configuration can be simplified as compared with the first embodiment.

  In this embodiment, the ignition antenna module 41 ′ of the second embodiment can also be used.

<Other applications of the present invention>
The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the idea of the present invention. For example, the circuit configuration of the microwave output unit 30 and the circuit configurations of the antenna unit 40 and the main amplifier 48 are not limited to the above embodiment.

  Moreover, although the case where the four slots 51a of the antenna 51 were provided equally was shown in the said embodiment, five or more may be provided equally, and although efficiency falls a little, 1-3 may be sufficient. . In addition, the slot formed in the planar slot antenna 51 is preferably a fan shape because the length of the slot itself can be reduced and the size can be reduced, but the present invention is not limited to this.

  Furthermore, in the above-described embodiment, the etching processing apparatus is exemplified as the plasma processing apparatus. However, the present invention is not limited to this, and the plasma processing apparatus can be used for other plasma processing such as film formation processing, oxynitride film processing, and ashing processing. Furthermore, in the above-described embodiment, plasma processing using microwaves as electromagnetic waves has been described. However, the present invention is not limited to microwaves but can be applied to plasma processing using other electromagnetic waves.

  Furthermore, the substrate to be processed is not limited to the semiconductor wafer W, and may be another substrate such as an FPD (flat panel display) substrate typified by an LCD (liquid crystal display) substrate or a ceramic substrate.

DESCRIPTION OF SYMBOLS 1; Chamber 2; Microwave plasma source 11; Susceptor 12; Support member 15; Exhaust pipe 16; Exhaust device 17; Carry-in / out port 20; Shower plate 21; Supply source 26; Plasma gas introducing member 27; Plasma gas supply source 30; Microwave output unit 32; Microwave oscillator 34; Distributor 40; Antenna unit 41; Antenna module 41 '; Antenna module for ignition 42; Microwave introduction mechanism 44; tuner 45; antenna section 46; phase shifter 47; variable gain amplifier 48; main amplifier 49; isolator 50; main body container 51; planar slot antenna 51a; Top plate 58; Slag 59; Actuator 60; Controller 70, 70 '; microwave synthesizer unit 71; the upper dielectric plate 72; the lower the dielectric plate 74; Synthesis space 80; the control unit 100; the plasma processing apparatus W; semiconductor wafer

Claims (18)

A plasma source that introduces electromagnetic waves into a processing vessel for performing plasma processing and turns the gas supplied into the processing vessel into plasma,
An electromagnetic wave generating mechanism for generating an electromagnetic wave;
A plurality of antenna modules for introducing the generated electromagnetic waves into the processing container;
An electromagnetic wave synthesizing unit that is provided adjacent to the processing container and synthesizes electromagnetic waves radiated from the plurality of antenna modules;
The electromagnetic wave synthesis unit includes a synthetic space that spatially synthesizes electromagnetic waves radiated from the plurality of antenna modules, and a dielectric member provided between the synthetic space and the chamber,
The plasma source, wherein the electromagnetic wave synthesized in the synthetic space is introduced into the processing container through the dielectric member.   The plasma source according to claim 1, wherein the synthetic space is a free space having a dielectric constant of 1.0.   The plasma source according to claim 2, wherein the height of the synthetic space is 1/12 or more of the wavelength of electromagnetic waves.   4. The plasma source according to claim 2, wherein the pressure in the synthesis space is 200 Torr (26660 Pa) or more or 0.1 mTorr (0.0133 Pa) or less.   The plasma source according to claim 4, wherein the pressure in the synthesis space is atmospheric pressure. A plasma source that introduces electromagnetic waves into a processing vessel for performing plasma processing and turns the gas supplied into the processing vessel into plasma,
An electromagnetic wave generating mechanism for generating an electromagnetic wave;
A plurality of antenna modules for introducing the generated electromagnetic waves into the processing container;
An electromagnetic wave synthesizing unit that is provided adjacent to the processing container and synthesizes electromagnetic waves radiated from the plurality of antenna modules;
The electromagnetic wave synthesis unit includes a synthetic dielectric member made of a dielectric material that synthesizes electromagnetic waves radiated from the plurality of antenna modules,
A plasma source, wherein an electromagnetic wave synthesized in the synthetic dielectric member is introduced into the processing container.   The plasma source according to claim 6, wherein the synthetic dielectric member has a thickness of λg / 12 or more when an effective wavelength of microwaves in the synthetic dielectric member is λg.   The plasma source according to claim 6 or 7, wherein the synthetic dielectric member is made of quartz or ceramics.   The plasma source according to any one of claims 1 to 8, further comprising plasma ignition means for igniting plasma in the processing vessel.   10. The plasma source according to claim 9, wherein the plasma ignition means includes an ignition antenna module that guides electromagnetic waves to the processing container via the dielectric member without passing through the synthetic space.   11. The plasma source according to claim 10, wherein the ignition antenna module induces an electric field in the processing container through a central portion of the dielectric member.   The plasma source according to claim 9, wherein the plasma ignition means includes a direct current ignition source provided in the processing container.   The plasma source according to any one of claims 1 to 12, further comprising an electromagnetic wave pattern adjusting unit that adjusts a plasma distribution by adjusting a pattern of the electromagnetic wave synthesized by the electromagnetic wave synthesizing unit. .   14. The plasma source according to claim 13, wherein the electromagnetic wave pattern adjusting unit includes a phase shifter provided in each antenna module and configured to adjust a phase of an electromagnetic wave radiated from each antenna module.   The plasma source according to claim 13 or 14, wherein the electromagnetic wave pattern adjusting means includes an amplifier that is provided in each antenna module and adjusts the power of an electromagnetic wave radiated from each antenna module. Each antenna module is
A cylindrical container,
An inner conductor that is coaxially provided in the main body container and forms an electromagnetic wave transmission path between the main body container and a cylindrical shape or a rod shape,
A tuner for adjusting impedance in the electromagnetic wave transmission path;
16. The electromagnetic wave introduction mechanism comprising an antenna unit having an electromagnetic wave radiation antenna that radiates an electromagnetic wave transmitted through the electromagnetic wave transmission path into the processing container. The plasma source described in 1. A processing container for storing a substrate to be processed;
A mounting table on which a substrate to be processed is mounted in the processing container;
A gas supply mechanism for supplying gas into the processing container;
A plasma source according to any one of claims 1 to 16,
A plasma processing apparatus for processing a substrate to be processed in the processing container by plasma.   18. The plasma processing apparatus according to claim 17, further comprising a high-frequency bias applying mechanism that applies a high-frequency bias power for ion attraction to the mounting table.

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