JP2012216525A - Plasma processing apparatus and plasma generation antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma processing apparatus and a plasma generation antenna, capable of supplying gas and an electromagnetic wave.SOLUTION: A plasma processing apparatus includes: a processing container in which a plasma processing is performed; a wavelength shortening plate 480 configured to transmit an electromagnetic wave supplied thereto; and a plasma generation antenna 200 having a shower head 210 provided adjacent to the wavelength shortening plate 480. The shower head 210 is formed of a conductor, has a plurality of gas holes 215 formed therein and has a plurality of slots 220 through which the electromagnetic wave passes, the slots 220 being provided at positions isolated from the gas holes 215.

Description

  The present invention relates to a plasma processing apparatus and a plasma generating antenna. In particular, the present invention relates to a structure of a plasma generating antenna and a plasma processing apparatus using the same.

  Plasma processing is an essential technology for manufacturing semiconductor devices. In recent years, due to the demand for higher integration and higher speed of LSI, further fine processing of semiconductor elements constituting the LSI is required.

  However, in the capacitively coupled plasma processing apparatus and the inductively coupled plasma processing apparatus, a region where the electron temperature of the generated plasma is high and the plasma density is high is limited. For this reason, it has been difficult to realize plasma processing in response to a request for further microfabrication of a semiconductor element.

  Therefore, in order to realize such fine processing, it is necessary to generate plasma with a low electron temperature and a high plasma density. In order to respond to this, an apparatus has been proposed in which surface wave plasma is generated in a processing vessel by a microwave and thereby a semiconductor wafer is subjected to plasma processing (see, for example, Patent Documents 1 and 2).

  In Patent Documents 1 and 2, a microwave is transmitted to a coaxial tube and radiated into a processing vessel, and a surface wave having a low electron temperature and a high plasma density is obtained by exciting a gas with the electric field energy of the microwave surface wave. A plasma processing apparatus for generating plasma has been proposed.

JP 2003-188103 A JP 2003-234327 A

  However, in the plasma processing apparatus of Patent Document 1, in order to radiate microwaves from the coaxial tube into the processing container, the top plate has a structure in which a surface wave plasma and a slot are sandwiched between dielectric plates such as quartz. Thus, the gas is supplied from the side wall of the processing container into the processing container. Thus, since the gas was supplied from the outside of the top plate, the gas flow could not be controlled, and it was difficult to perform good plasma control. Further, even when the top plate is formed of a conductor, a mechanism that can emit electromagnetic waves from the top plate into the processing container has not been disclosed.

  In view of the above problems, an object of the present invention is to provide a plasma processing apparatus and a plasma generating antenna capable of supplying gas and electromagnetic waves.

  In order to solve the above-described problem, according to an aspect of the present invention, a processing container in which plasma processing is performed, a slow wave plate that transmits a supplied electromagnetic wave, and the slow wave plate are provided adjacent to each other. A plasma generating antenna having a shower head, wherein the shower head is formed of a conductor, has a plurality of gas holes, and has a plurality of slots through which electromagnetic waves pass to positions separated from the gas holes. A plasma processing apparatus is provided.

  The plasma processing apparatus may include a plurality of plasma generating antennas.

  The shower head may propagate a surface wave to a surface exposed to the plasma space side.

  In the shower head, the plurality of gas holes may be formed inside and outside the plurality of slots.

  You may further provide the gas path which supplies the gas to the several gas hole formed inside the said slot through the part which divides | segments the said several slot.

  The gas path may be divided into a plurality of gas paths capable of supplying a plurality of gases separately.

  A mechanism for applying a DC voltage to the shower head may be further provided.

  The mechanism for applying a DC voltage to the shower head may include an insulating member between the coaxial tube and the mechanism.

  The plurality of slots may be filled with a dielectric member.

  The plurality of slots may be formed symmetrically with respect to the central axis of the plasma generating antenna.

  On the surface of the shower head, spraying may be performed or a top plate may be fixed, and openings that communicate with the plurality of slots and the plurality of gas holes may be formed.

  The shower head may be formed of silicon, and the surface of the shower head may be exposed.

  In order to solve the above-mentioned problems, according to another aspect of the present invention, a shower formed of a conductor and having a plurality of gas holes and a plurality of slots through which electromagnetic waves pass to positions separated from the plurality of gas holes. There is provided a plasma generating antenna comprising a head.

  As described above, according to the present invention, it is possible to provide a plasma processing apparatus and a plasma generating antenna capable of supplying gas and electromagnetic waves.

It is a schematic longitudinal cross-sectional view of the plasma processing apparatus which concerns on 1st Embodiment. It is the figure which showed the mechanism of the output side of the microwave which concerns on 1st Embodiment. It is an enlarged view of the antenna for plasma generation concerning a 1st embodiment. It is a bottom view of the shower head concerning a 1st embodiment. It is the figure which showed the modification of slot shape. It is an enlarged view of the antenna for plasma generation concerning 2nd Embodiment. It is an enlarged view of the antenna for plasma generation concerning a modification. It is an enlarged view of the antenna for plasma generation concerning 3rd Embodiment. It is the figure which showed the antenna for plasma generation concerning 4th Embodiment. It is the figure which showed the mechanism of the output side of the microwave which concerns on 4th Embodiment. It is the figure which showed the modification of the antenna for plasma generation which concerns on 4th Embodiment. It is the figure which showed the modification of the antenna for plasma generation which concerns on 4th Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

In addition, embodiment of this invention is described by the following content in order of 1st-4th embodiment.
<First Embodiment>
[Configuration of plasma processing apparatus]
[Configuration of plasma generation antenna]
[Modification of slot]
Second Embodiment
[Configuration of plasma generation antenna]
<Third Embodiment>
[Configuration of plasma generation antenna]
<Fourth embodiment>
[Configuration of plasma generation antenna]
[Operation of plasma generating antenna]

<First Embodiment>
[Configuration of plasma processing apparatus]
First, the overall configuration of the plasma processing apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view schematically showing a plasma processing apparatus.

  In the present embodiment, the plasma processing apparatus 10 will be described using an example of an etching apparatus that performs an etching process as a plasma process on a semiconductor wafer W (hereinafter referred to as a wafer W). The plasma processing apparatus 10 includes a processing container 100 that plasma-processes the wafer W inside an airtightly held interior. The processing container 100 is cylindrical and is made of, for example, a metal such as aluminum and grounded.

  A susceptor 105 on which the wafer W is placed is provided at the bottom of the processing container 100. The susceptor 105 is made of a metal such as aluminum, is supported by a support member 115 via an insulator 110, and is installed at the bottom of the processing vessel 100. Thereby, the susceptor 105 is in an electrically floating state. Examples of the material of the susceptor 105 and the support member 115 include aluminum whose surfaces are anodized (anodized).

  A high frequency power supply 125 for bias is connected to the susceptor 105 via a matching unit 120. The high frequency power supply 125 applies a high frequency power for bias to the susceptor 105, whereby ions in the plasma are attracted to the wafer W side. Although not shown, the susceptor 105 includes an electrostatic chuck for electrostatically attracting the wafer W, a temperature control mechanism, a gas flow path for supplying a heat transfer gas to the back surface of the wafer W, and the wafer. Lift pins or the like that move up and down when transporting W may be provided.

  An exhaust port 130 is provided at the bottom of the processing container 100, and an exhaust device 135 including a vacuum pump (not shown) is connected to the exhaust port 130. When the exhaust device 135 is operated, the inside of the processing container 100 is exhausted and the pressure is reduced to a desired degree of vacuum. A loading / unloading port 140 is formed on the side wall of the processing chamber 100, and the wafer W is loaded / unloaded by opening / closing a gate valve 145 that can open / close the loading / unloading port 140.

  Above the susceptor 105, a plasma generating antenna 200 (hereinafter referred to as the antenna 200) capable of supplying electromagnetic waves (here, microwaves) while supplying gas is mounted. The antenna 200 is provided at the opening of the lid 150. Thereby, a plasma space U is formed between the susceptor 105 and the antenna 200. A microwave transmission mechanism 400 serving as an electromagnetic wave transmission mechanism for transmitting microwaves is connected to the upper part of the antenna 200, and the microwaves output from the microwave output unit 300 are transmitted to the antenna 200.

  The control device 500 controls a DC voltage or the like applied to the antenna 200 as will be described later. The control device 500 includes a control unit 505 and a storage unit 510. The control unit 505 controls the DC voltage applied to the antenna 200 for each process according to the recipe stored in the storage unit 510. The command to the control device 500 is executed by a dedicated control device or a CPU (not shown) that executes a program. Recipes for which process conditions are set are stored in advance in a ROM or a non-volatile memory (both not shown), and the CPU reads the recipe conditions from these memories and executes them.

  The configuration of the microwave output unit 300 and the microwave transmission mechanism 400 will be described with reference to FIG. The left side of FIG. 2 shows the internal configuration of the microwave output unit 300. The right side of FIG. 2 shows the internal configuration of the microwave transmission mechanism 400.

  The microwave output unit 300 includes a microwave power source 305, a microwave oscillator 310, and an amplifier 315. The microwave power source 305 outputs microwaves having frequencies such as 2.45 GHz, 8.35 GHz, 5.8 GHz, and 1.98 GHz. The microwave power source 305 is an example of an electromagnetic wave source, and outputs a microwave band electromagnetic wave. The electromagnetic wave source is not limited to a microwave but a power source that outputs an electromagnetic wave from a 100 MHz RF band to a 3 GHz microwave band. The microwave oscillator 310 performs PLL oscillation of microwaves having a predetermined frequency of 2.45 GHz, for example. The amplifier 315 amplifies the oscillated microwave.

  The microwave transmission mechanism 400 includes an antenna module 410 and a microwave introduction mechanism 450. The antenna module 410 includes a phase shifter 412, a variable gain amplifier 414, a main amplifier 416, and an isolator 418, and transmits the microwave output from the microwave output unit 300 to the microwave introduction mechanism 450.

  The phase shifter 412 is configured to change the phase of the microwave by the slag tuner, and by adjusting this, the radiation characteristic can be modulated. According to this, the plasma distribution can be changed by controlling the directivity. Note that the phase shifter 412 does not need to be provided when such modulation of radiation characteristics is unnecessary.

  The variable gain amplifier 414 adjusts the power level of the microwave input to the main amplifier 416 and adjusts the plasma intensity. The main amplifier 416 constitutes a solid state amplifier. The solid state amplifier can be configured to include an input matching circuit, a semiconductor amplifying element, an output matching circuit, and a high Q resonance circuit which are not shown.

  The isolator 418 separates the reflected wave of the microwave reflected by the antenna 200 and returning to the main amplifier 416, and has a circulator and a dummy load (coaxial terminator). The circulator guides the microwave reflected by the antenna 200 to the dummy load, and the dummy load converts the microwave reflected wave guided by the circulator into heat.

[Configuration of plasma generation antenna]
Next, configurations of the microwave introduction mechanism 450 and the plasma generating antenna 200 according to the first embodiment will be described with reference to FIG. FIG. 3 is an enlarged view (left half) of the microwave introduction mechanism 450 and the antenna 200 according to the first embodiment.

  The microwave introduction mechanism 450 includes a coaxial tube 455 and a slow wave plate 480. The coaxial tube 455 has a coaxial waveguide composed of a cylindrical outer conductor 455a and a rod-shaped inner conductor 455b provided at the center thereof. An antenna 200 is provided at the lower end of the coaxial tube 455 via a slow wave plate 480. The coaxial tube 455 has an inner conductor 455b on the power supply side and an outer conductor 455a on the ground side. The coaxial tube 455 is provided with a tuner 470. The tuner 470 includes two slags 470a and constitutes a slag tuner. The slug 470a is configured as a dielectric plate, and is provided in an annular shape between the inner conductor 455b and the outer conductor 455a of the coaxial tube 455. The tuner 470 adjusts the impedance by moving the slug 470a up and down by an actuator (not shown) based on a command from the control unit 505. For example, the control unit 505 adjusts the impedance so that the characteristic impedance is 50Ω at the end of the coaxial tube 455.

  The slow wave plate 480 is provided adjacent to the lower surface of the coaxial tube 455. The slow wave plate 480 is formed from a disk-shaped dielectric member. The slow wave plate 480 transmits the microwave transmitted through the coaxial tube 455 and guides it to the antenna 200.

  The antenna 200 has a shower head (gas shower head) 210 and a mechanism for applying a DC voltage to the shower head 210 (hereinafter referred to as a DC application mechanism 250). The shower head 210 is provided adjacent to the lower surface of the slow wave plate 480. The shower head 210 has a disk shape whose diameter is larger than that of the slow wave plate 480, and is formed of a conductor having high electrical conductivity such as aluminum or copper. The shower head 210 is exposed to the plasma space U side, and propagates surface waves to the exposed lower surface. Here, the metal surface of the shower head 210 is exposed to the plasma space U side. Hereinafter, the surface wave propagating to the exposed lower surface is referred to as a metal surface wave.

The shower head 210 has a plurality of gas holes 215 and a plurality of slots 220 through which microwaves pass at positions separated from the gas holes 215. A gas path 225 is formed in the shower head 210 in a radial direction of the shower head 210 through the side surface. Gas is supplied from a gas supply source 600 (see FIG. 1), passes through a gas supply pipe 605, enters a plurality of gas holes 215 from a gas path 225, and is introduced into the processing container from each gas hole 215. The surface exposed to the plasma side of the shower head 210 is covered with a coating 290 of alumina (Al ₂ O ₃ ) or yttria (Y ₂ O ₃ ) by thermal spraying so that the conductor surface is not exposed to the plasma space side. The coating 290 is formed with openings that communicate with the plurality of slots 220 and the plurality of gas holes 215.

  The shower head 210 is provided with a cooling path (not shown) so as to cool the shower head 210. Since the shower head 210 is a conductor having high electrical conductivity, heat from the slot 220 which is a microwave transmission path can be efficiently released to the processing container main body side.

  The plurality of slots 220 are provided at positions separated from the gas passages 225 and the plurality of gas holes 215 that are gas supply passages, and pass through in a direction perpendicular to the radial direction of the shower head 210. One end of the slot 220 is adjacent to the slow wave plate 480 and the other end is opened to the plasma space U side. The microwave is transmitted through the coaxial tube 455, passes through the slow wave plate 480, passes through the plurality of slots 220, and is radiated to the plasma space U.

  FIG. 4 is a view showing a surface (lower surface) exposed to the plasma space U of the shower head 210. A plurality of gas holes 215 are arranged substantially evenly. The gas holes 215 are provided on the outer peripheral side and the inner peripheral side of the substantially ring-shaped slot 220. The slot 220 is not formed in a complete ring shape, but has a fan shape divided into four. In the portion A where the slot 220 is partitioned, the gas path 225 is formed so as not to communicate with the slot 220, and gas is supplied to the gas hole 215 provided on the inner peripheral side of the slot 220. Therefore, at least one partition for passing the gas path 225 is necessary for the slot 220. Therefore, in the present embodiment, there are four slots 220, but the present invention is not limited to this, and it is only necessary to have at least one delimiter.

  The plurality of slots 220 are formed symmetrically with respect to the central axis of the antenna 200 (the central axis O in FIG. 3). As a result, microwaves can be emitted more uniformly from the slots 220.

  The gas hole 215 is a thin hole so that the microwave radiated into the plasma space U does not enter the gas hole 215. Further, the slot 220 and the gas hole 215 are completely separated in the shower head 210. Thereby, abnormal discharge in the gas path 225 or the gas hole 215 can be prevented.

  Returning to FIG. 3 again, an O-ring 485 and an O-ring 495 are provided on the contact surface between the slow wave plate 480 and the shower head 210, and the shower head 210 and the processing space from the microwave transmission mechanism 400 provided on the atmosphere side. The inside of 100 is vacuum-sealed. Thereby, the inside of the plasma space U, the slot 220, the gas path 225, and the gas hole 215 can be made into a vacuum state.

  When the shower head 210 is a conductor as in the present embodiment, a DC voltage (direct current voltage) can be applied to the shower head 210. Specifically, the DC voltage output from the DC power supply 255 is supplied to the DC application mechanism 250 in accordance with a command from the control unit 505. The DC application mechanism 250 includes a DC electrode 260, an insulating member 265, and an insulating sheet 270. The DC electrode 260 has a cylindrical conductor 260 a and is connected to the shower head 210 via the cylindrical conductor 260 a, thereby applying a DC voltage to the shower head 210. The DC electrode 260 is screwed to the shower head 210 by an insulating socket (not shown) provided at the lower end of the cylindrical conductor 260a.

  The DC electrode 260 is close to the outer conductor 455a of the coaxial tube 455 and the lid 150. Therefore, in order to insulate the DC electrode 260 and the coaxial tube 455 and the DC electrode 260 and the lid 150 in a DC manner, the DC electrode 260 is covered with an insulating member 265, and the DC electrode 260, the coaxial tube 455, the DC electrode 260 and the lid 150 are covered. Insulate. Further, in order to insulate the shower head 210 and the coaxial tube 455 and the shower head 210 and the lid 150 in a DC manner, the insulation is provided between the shower head 210 and the coaxial tube 455 and between the shower head 210 and the lid 150. The sheet 270 is sandwiched. In this way, by insulating the processing vessel 100 in a DC manner, a DC voltage is applied only to the shower head 210, and the number of members to which the DC voltage is applied can be reduced as much as possible. Note that when the shower head 210 is formed of an insulator, a DC voltage cannot be applied to the shower head 210. However, in that case, the same effect can be expected if an RF voltage is applied.

  As described above, according to the plasma processing apparatus 10 according to the present embodiment, the microwave introduced from the coaxial tube 455 passes through the slow wave plate 480 and passes through the shower head 210. Radiated to the plasma space U through the slot 220. At that time, a standing wave (metal surface wave) having a wavelength characterized by a dispersion relation with a plasma sheath as a boundary condition is generated on the surface of the shower head 210 and absorbed by the surface wave plasma. The gas supplied from the gas supply source 600 is also introduced into the plasma space U through the shower head 210. The introduced gas is excited by surface wave plasma. As a result, plasma having a low electron temperature and a high plasma density is generated in the plasma space U in the processing container 100. The generated plasma is used for etching the wafer W. Since the plasma has a low electron temperature, the wafer W is not easily damaged, and since it has a high plasma density, the wafer W can be finely processed at high speed. Further, by forming the shower head 210 with a conductor, a process such as reactive etching can be performed.

  In the case of a general surface wave plasma source, a dielectric is installed under the antenna slot, and when a showerhead structure is made in the dielectric, electromagnetic waves pass through the dielectric, causing abnormal discharge inside it. Therefore, it is extremely difficult to adopt a showerhead structure with a general surface wave plasma source. For example, in argon plasma, when a space of 10 mm is vacant in the shower head space, if a voltage of about 120 volts is generated in the shower head along the distance, abnormal discharge occurs in the shower head at a pressure of 1 Torr. The possibility increases.

  On the other hand, in the plasma processing apparatus 10 according to the present embodiment, the shower head 210 is made of a conductor such as metal, so that electromagnetic waves do not enter the shower head 210 and there is no electric field inside the shower head 210. be equivalent to. Therefore, abnormal discharge does not occur. The electromagnetic wave and the gas are isolated inside the shower head 210, and contact with each other only after entering the processing container 100. Therefore, by using the plasma processing apparatus 10 according to the present embodiment, it is possible to generate surface wave plasma without abnormal discharge while uniformly discharging gas with the shower head 210.

  In addition, according to the plasma processing apparatus 10 according to the present embodiment, it is possible to apply a microwave to the same shower head 210 while applying a DC voltage to the shower head 210. Thereby, the plasma processing apparatus 10 can be applied to various processes. For example, when a microwave is applied, a surface wave propagates to the surface of the shower head 210. At this time, a sheath region is generated on the surface of the shower head 210, and surface waves propagate through the sheath. The DC voltage controls the thickness of the sheath. For example, when a DC voltage is applied to the shower head 210, the sheath can be controlled to be thick, and as a result, the propagation distance of the surface wave propagating on the surface of the shower head 210 can be increased. Thus, by manipulating the plasma sheath voltage by controlling the DC voltage, the propagation distance of the surface wave can be controlled, and the electron density and radical density of the plasma can be optimized.

[Modification of slot]
A modification of the slot formed in the antenna 200 will be described with reference to FIG. The slots 220 having different shapes are illustrated on the upper side, the center, and the lower side of FIG. The upper slot in FIG. 5 is divided into six slots 220. Each slot 220 has the same shape that is thick at the center and thin at both ends. Both ends of the adjacent slots 220 are opposed to each other.

  The central slot in FIG. 5 is divided into six slots 220. The center of each slot 220 is as thin as both ends. Each slot 220 has the same shape that is slightly curved and inclined in an oblique direction. Both ends of the adjacent slots 220 are opposed to each other.

  The bottom slot in FIG. 5 has a two-stage slot structure in which the outer peripheral side is divided into four slots 220 and the inner peripheral side is also divided into four slots 220. Each slot 220 has an arc shape with the same thickness and the same shape. The partition between the outer peripheral slots 220 is positioned at the center of the inner peripheral slot 220, and the partition between the inner peripheral slots 220 is positioned at the center of the outer peripheral slot 220.

  In any of the modifications, the plurality of slots 220 are formed symmetrically with respect to the central axis of the antenna 200. Thereby, a microwave can be uniformly emitted into the processing container 100. Further, the plurality of slots 220 have at least one delimiter. Thereby, gas can be supplied from the gas hole 215 (not shown) formed in the outer peripheral side and inner peripheral side of the slot 220.

Second Embodiment
[Configuration of plasma generation antenna]
Next, the configuration of the plasma generating antenna according to the second embodiment will be described with reference to FIG. FIG. 6 is an enlarged view (left half) of the plasma generating antenna 200 according to the second embodiment. The plasma generating antenna 200 according to the second embodiment can be applied to the antenna portion of the plasma processing apparatus 10 of FIG. 1 instead of the antenna according to the first embodiment.

  The plurality of slots 220 according to the second embodiment are filled with a dielectric member 220a. Quartz or the like may be used as the dielectric member 220a. Thereby, it is possible to prevent the plasma from entering the slot 220.

  In the second embodiment, a silicon top plate 700 is fixed to an exposed surface on the plasma space side of a shower head 210 made of, for example, aluminum. Thereby, the top plate 700 damaged by the plasma can be replaced, and the life of the shower head 210 can be extended. The top plate 700 is formed with openings that communicate with the plurality of slots 220 and the plurality of gas holes 215. An opening communicating with the slot 220 is filled with a dielectric member 220 a in the same manner as the slot 220.

<Modification>
As a modification of the above embodiment, a case where the shower head 210 is made of silicon will be described. In that case, the silicon surface of the shower head 210 is exposed as it is, as shown in FIG. 7, without spraying the shower head 210 or providing the top plate 700.

  Also in the case of the second embodiment and the modification, it is possible to apply a microwave to the same shower head 210 while applying a DC voltage to the shower head 210. Thereby, the plasma processing apparatus 10 can be applied to various processes. For example, when a microwave is applied, a surface wave propagates to the surface of the shower head 210. At this time, a sheath region is generated on the surface of the shower head 210, and surface waves propagate through the sheath. The DC voltage controls the thickness of the sheath. For example, when a DC voltage is applied to the shower head 210, the sheath can be controlled to be thick, and as a result, the propagation distance of the surface wave propagating on the surface of the shower head 210 can be increased. Thus, by manipulating the plasma sheath voltage by controlling the DC voltage, the propagation distance of the surface wave can be controlled, and the electron temperature of the plasma can be optimized. Further, in the case of the modification, when a DC voltage is applied to the shower head 210, silicon can be knocked out from the shower head 210, thereby increasing the etching selectivity.

  Depending on the gas type, pressure, and high-frequency power at the time of plasma generation, the plasma may be excessively concentrated in the vicinity of the slot 220, and the plasma uniformity may be disturbed. However, as described above, according to the plasma processing apparatus 10 according to the present embodiment, the slot 220 is filled with the dielectric member 220a. For this reason, it is possible to prevent plasma from entering the slot 220. Thereby, the uniformity of plasma can be improved. Further, the effective wavelength of the microwave passing through the slot can be shortened by the dielectric member 220a in the slot 220. Thereby, the thickness of the shower head 210 can be made thin.

<Third Embodiment>
[Configuration of plasma generation antenna]
Next, the configuration of the plasma generating antenna according to the third embodiment will be described with reference to FIG. FIG. 8 is an enlarged view (left half) of the plasma generating antenna according to the third embodiment. The plasma generating antenna 200 according to the third embodiment can be applied to the antenna portion of the plasma processing apparatus 10 of FIG. 1 instead of the antenna according to the first embodiment.

  The gas path of the shower head 200 according to the third embodiment is divided into a first gas path 225a and a second gas path 225b. The first gas path 225a and the second gas path 225b are completely separated. The first gas path 225a is connected to the gas supply pipe 605a. The second gas path 225b is connected to the gas supply pipe 605b. A desired gas 1 is supplied from a gas supply source 600 (see FIG. 1), passes through a gas supply pipe 605a, enters a plurality of gas holes 215 from a gas path 225a, and is introduced into the processing vessel from each gas hole 215. . The desired gas 2 is supplied from a gas supply source 600 (see FIG. 1), passes through a gas supply pipe 605b, enters another gas hole 215 from a gas path 225b, and is introduced into the processing container from each gas hole 215. Is done. Thereby, different types of gases can be alternately introduced from adjacent gas holes.

  As described above, according to the plasma processing apparatus 10 according to the present embodiment, two independent shower head spaces (matrix showers) are provided in the shower head 200, thereby controlling the flow of gas in two systems. To do. The gas is supplied from each shower head to the processing container 100 and mixed in the space in the processing container, so that two or more gases can be reacted (postmix). According to this, the gas introduction position can be optimized depending on the gas type, and a desired plasma can be generated. The gas path is not limited to two systems, and may be divided into three or more gas paths that can be supplied separately without mixing three or more kinds of gases.

<Fourth embodiment>
[Configuration of plasma generation antenna]
Next, the configuration of the plasma generating antenna according to the fourth embodiment will be described with reference to FIGS. FIG. 9 is a view showing an antenna portion of the plasma processing apparatus according to the fourth embodiment. In FIG. 9, the portion below the antenna 200 is omitted, but the plasma processing apparatus 10 according to the fourth embodiment has the same configuration as the plasma processing apparatus according to the first embodiment. FIG. 10 is a diagram illustrating the configuration of the microwave output unit 300 and the microwave transmission mechanism 400.

  In the plasma processing apparatus 10 according to the fourth embodiment, three antennas 200 are provided on the lid 150. Since the basic structure of each antenna 200 has been described in the first embodiment, a description thereof is omitted here.

  In the plasma processing apparatus 10 according to the fourth embodiment, the microwave is output from the microwave power source 305 shown in the microwave output unit 300 of FIG. 10, and is distributed via the microwave oscillator 310 and the amplifier 315. Distributed at.

  Specifically, the microwave oscillator 310 performs PLL oscillation of a microwave having a predetermined frequency of 2.45 GHz, for example. The amplifier 315 amplifies the oscillated microwave. The distributor 320 distributes the amplified microwave into a plurality of parts. The distributor 320 distributes the microwave amplified by the amplifier 315 while matching the impedance between the input side and the output side so that the microwave is not lost as much as possible. The distributed microwaves are transmitted to each antenna module 410.

  In the present embodiment, the microwave transmission mechanism 400 includes three antenna modules 410 that transmit the microwaves distributed by the distributor 320. Each antenna module 410 radiates microwaves into the processing container 100 from the coaxial tube 455 connected to each antenna module 410, and spatially synthesizes the microwaves therein. Therefore, the isolator 418 may be small and can be provided adjacent to the main amplifier 416.

  The phase shifter 412 of each antenna module 410 is configured to change the phase of the microwave by the slag tuner, and by adjusting this, the radiation characteristic can be modulated. For example, by adjusting the phase for each antenna module 410, the directivity can be controlled to change the plasma distribution, or circular polarization can be obtained by shifting the phase by 90 ° between adjacent antenna modules 410. it can. Note that the phase shifter 412 does not need to be provided when such modulation of radiation characteristics is unnecessary.

  The variable gain amplifier 414 adjusts the power level of the microwave input to the main amplifier 416, and adjusts the variation of the individual antenna modules 410 and the plasma intensity. By changing the variable gain amplifier 414 for each antenna module 410, the generated plasma can be distributed.

  The main amplifier 416 constitutes a solid state amplifier. The solid state amplifier can be configured to include an input matching circuit, a semiconductor amplifying element, an output matching circuit, and a high Q resonance circuit which are not shown.

  The isolator 418 separates the reflected wave of the microwave reflected by the antenna 200 toward the main amplifier 416, and has a circulator and a dummy load (coaxial terminator). The circulator guides the microwave reflected by the antenna 200 to the dummy load, and the dummy load converts the microwave reflected wave guided by the circulator into heat. The microwave output from the antenna module 410 is transmitted to the microwave introduction mechanism 450 and guided to the antenna 200.

  In the present embodiment, the three antennas 200 are individually provided on the lid 150, and the gas supply pipe 605 is provided for each. In other words, the shower head 210 is provided independently for each antenna 200. However, it is easier to produce one shower head 210 for a plurality of antennas 200 than to provide a plurality of shower heads 210 on the lid 150. Therefore, as a modification of the present embodiment, for example, as shown in FIG. 11, one shower head 210 may be provided in common for the three antennas 200. In such a case, one gas supply pipe 605 is provided for the common shower head 210. In FIG. 11, the basic structure of each antenna 200 is the same as that shown in FIG. 9 except that the shower head 210 and the gas supply pipe 605 are shared by a plurality of antennas 200.

  When a plurality of antennas 200 are provided in common in one shower head 210, for example, the independent annular gas paths 225 may be formed concentrically around the central axis of the lid 150. In such a case, the gas paths 225 are isolated from each other. Specifically, for example, as shown in FIG. 12, the annular gas passages 225 c and 225 d of the inner and outer two systems are formed in the shower head 210. A gas supply pipe 605 is provided in each gas path 225c, 225d. By doing so, the flow rate of the gas introduced into the plasma space U and the type of the introduced gas can be made different between the central region of the shower head 210 and the outer region.

[Operation of plasma generating antenna]
Finally, the operation of the plasma processing apparatus 10 according to the first to fourth embodiments will be described with reference to FIG. First, the wafer W is loaded into the processing container 100 and placed on the susceptor 105. Then, for example, a plasma gas such as Ar gas is supplied from the gas supply source 600 and introduced into the processing container 100 from the shower plate 200 through the gas supply pipe 605. The microwave is output from the microwave output unit 300 and introduced into the processing container 100 through the microwave transmission mechanism 400, the retardation plate 480, and the slot 220. Plasma gas is excited by the electric field energy of the microwave, and plasma is generated.

Next, for example, an etching gas such as Cl ₂ gas is supplied from the gas supply source 600 and introduced into the processing container 100 from the shower plate 200 through the gas supply pipe 605 branched into a plurality of parts. The etching gas is similarly excited and turned into plasma. For example, an etching process is performed on the wafer W by the plasma of the processing gas thus formed. Since the plasma has a low electron temperature, the wafer W is not easily damaged, and since it has a high plasma density, the wafer W can be finely processed at high speed.

  In particular, in the plasma processing apparatus 10 according to the fourth embodiment, the microwave oscillated from the microwave oscillator 310 is amplified by the amplifier 315 and then distributed into a plurality by the distributor 320. The distributed microwave is guided to the plurality of antenna modules 410. In each antenna module 410, the plurality of microwaves distributed in this way are individually amplified by a main amplifier 416 constituting a solid state amplifier and transmitted to each microwave introduction mechanism 450. In each microwave introduction mechanism 450, the microwave is transmitted to the slow wave plate 480 using the coaxial tube 455. The microwave transmitted through the slow wave plate 480 is radiated from the slot 200 of each shower head 200 into the processing container.

  As described above, according to each embodiment, it is possible to provide the plasma generating antenna 200 and the plasma processing apparatus 10 capable of separately supplying gas and electromagnetic waves.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can make various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  For example, in the above embodiment, the etching process is described as an example of the plasma process performed in the plasma processing apparatus, but the present invention is not limited to such an example. For example, the plasma processing apparatus according to the present invention can execute any plasma processing such as film formation and ashing.

  Further, the plasma generating antenna according to the present invention is not limited to the microwave plasma processing apparatus described in the above embodiment, and any of inductively coupled ICP (Inductively Coupled Plasma) plasma processing apparatus, capacitively coupled plasma processing apparatus, etc. It can also be used for the plasma processing apparatus. The plasma processing apparatus according to the present invention can be applied to a process using surface wave plasma, a process using ICP plasma, and a process using CCP plasma.

  In each embodiment, the number of plasma generating antennas attached to the plasma processing apparatus is one or three. However, the number of plasma generating antennas attached to the plasma processing apparatus according to the present invention is not limited to this, and may be two, four, or more. However, in the case of a process including a step of hitting the wafer W with ions, a plasma processing apparatus having a plurality of plasma generating antennas is preferable. On the other hand, in the process of reacting the wafer W with radicals, a plasma processing apparatus having one plasma generating antenna is preferable.

  Further, the processing container of the plasma processing apparatus according to the present invention is not limited to a cylindrical shape, and may be, for example, a hexagonal shape or a rectangular shape. Therefore, the workpiece to be processed by the plasma processing apparatus according to the present invention is not limited to the disk-shaped semiconductor wafer, but may be a rectangular substrate, for example.

DESCRIPTION OF SYMBOLS 10 Plasma processing apparatus 100 Processing container 105 Susceptor 150 Lid 200 Plasma generating antenna 210 Shower head 215 Gas hole 220 Slot 225 Gas path 225a 1st gas path 225b 2nd gas path 250 DC application mechanism 255 DC power supply 260 DC electrode DESCRIPTION OF SYMBOLS 300 Microwave output part 400 Microwave transmission mechanism 410 Antenna module 450 Microwave introduction | transduction mechanism 455 Coaxial tube 455a Outer conductor 455b Inner conductor 480 Slow wave plate 500 Control apparatus 505 Control part 600 Gas supply source U Plasma space

Claims (15)

A processing vessel in which plasma processing is performed;
A slow wave plate that transmits the supplied electromagnetic wave;
A plasma generating antenna having a shower head provided adjacent to the slow wave plate,
The plasma processing apparatus, wherein the shower head is formed of a conductor, has a plurality of gas holes, and has a plurality of slots through which electromagnetic waves pass at positions separated from the gas holes.   The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus includes a plurality of antennas for generating plasma.   The plasma processing apparatus according to claim 2, wherein the shower head propagates a surface wave to a surface exposed to the plasma space side.   The plasma processing apparatus according to claim 3, wherein the plurality of gas holes are formed inside and outside the plurality of slots in the shower head.   5. The plasma processing apparatus according to claim 4, further comprising a gas path that supplies gas to a plurality of gas holes formed inside the slots through a portion that divides the plurality of slots.   The plasma processing apparatus according to claim 5, wherein the gas path is divided into a plurality of gas paths capable of separately supplying a plurality of gases.   The plasma processing apparatus according to claim 6, wherein the gas path is formed concentrically with respect to a central axis of the shower head.   The plasma processing apparatus according to any one of claims 3 to 7, wherein an electromagnetic wave transmission mechanism that adjusts the power of the surface wave is provided in each of the plurality of plasma generating antennas.   The plasma processing apparatus according to claim 1, further comprising a mechanism for applying a DC voltage to the shower head.   The plasma processing apparatus according to claim 9, wherein the mechanism that applies a DC voltage to the shower head includes an insulating member between the shower head and the coaxial tube.   The plasma processing apparatus according to claim 1, wherein the plurality of slots are filled with a dielectric member.   The plasma processing apparatus according to claim 1, wherein the plurality of slots are formed symmetrically with respect to a central axis of the plasma generating antenna.   The surface of the shower head is sprayed or a top plate is fixed, and openings that communicate with the plurality of slots and the plurality of gas holes are formed. The plasma processing apparatus according to any one of claims.   The plasma processing apparatus according to claim 1, wherein the shower head is made of silicon, and a surface of the shower head is exposed.   A plasma generating antenna comprising a shower head formed of a conductor and having a plurality of gas holes and a plurality of slots through which electromagnetic waves are passed to positions separated from the plurality of gas holes.

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