KR20120112261A - Plasma processing apparatus and plasma generation antenna - Google Patents

Abstract

PURPOSE: A plasma processing apparatus and a plasma generation antenna are provided to supply gas and electromagnetic waves which are separated from each other by providing a structure of separating the gas and the electromagnetic waves. CONSTITUTION: A plasma processing apparatus(10) has a process container(100) which processes a wafer with plasma in an internal space hermetically maintained. The process container is grounded in a cylindrical shape. A susceptor(105) mounting the wafer is installed in the bottom of the process container. A shower head is installed to be contiguous to the susceptor. The shower head is formed into a conductor having a plurality of gas holes. The shower head has the plurality of slots passing through electromagnetic waves in a separated location. The plasma processing apparatus includes a plurality of plasma generation antenna(200). [Reference numerals] (120) Matcher; (135) Exhaust device; (255) DC power supply; (300) Microwave output unit; (410) Antenna module; (505) Control unit; (510) Memory unit; (600) Gas supply source; (AA) Microwave transfer mechanism; (BB) Recipe

Description

Plasma Processing Equipment and Plasma Generating Antenna {PLASMA PROCESSING APPARATUS AND PLASMA GENERATION ANTENNA}

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

Plasma processing is an indispensable technique for the manufacture of semiconductor devices. In recent years, from the request for high integration and high speed of LSI, advanced microfabrication of semiconductor elements constituting LSI is required.

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

Therefore, in order to realize such microfabrication, it is necessary to generate a plasma of low electron temperature and high plasma density. In order to cope with this, an apparatus for generating surface wave plasma in a processing container by microwaves and thereby plasma processing a semiconductor wafer has been proposed (see Patent Documents 1 and 2, for example).

In Patent Documents 1 and 2, a plasma processing apparatus which transmits microwaves to a coaxial tube, radiates them in a processing container, and excites a gas by electric field energy of the surface waves of the microwaves, thereby generating a surface wave plasma having a low electron temperature and high plasma density. Is being proposed.

Patent Document 1: Japanese Patent Laid-Open No. 2003-188103 Patent Document 2: Japanese Patent Publication No. 2003-234327

However, in the plasma processing apparatus of Patent Document 1, in order to radiate microwaves from a coaxial tube into a processing container, the top plate has a structure in which a surface wave plasma and a slot are interposed with a dielectric plate such as quartz, and the gas is a side wall of the processing container. It became the structure supplied from the inside into a process container. In this way, since gas was supplied from outside the top plate, the flow of gas could not be controlled and good plasma control was difficult. In addition, even when the top plate is formed of a conductor, a mechanism capable of radiating electromagnetic waves from the top plate into the processing container has not been disclosed.

The object of the present invention is to provide a plasma processing apparatus and a plasma generating antenna capable of supplying gas and electromagnetic waves.

Moreover, in order to solve the said subject, According to one aspect of this invention, the plasma generation antenna which has the processing container to which a plasma process is performed, the slow wave plate which permeate | transmits the supplied electromagnetic wave, and the shower head provided adjacent to the said slow wave plate. And a shower head is formed of a conductor, a plurality of gas holes are formed, and a plurality of slots for passing electromagnetic waves in a position separated from the plurality of gas holes. .

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

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

The plurality of gas holes may be formed in the shower head inside and outside the plurality of slots.

A gas path may be further provided through a portion partitioning the plurality of slots and supply gas to a plurality of gas holes formed inside the slot.

The gas path may be divided into a plurality of gas paths that can separately supply a plurality of gases.

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

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

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

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

Spraying may be performed on the surface of the shower head, or a top plate may be fixed, and an opening communicating 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 problems, according to another aspect of the present invention, there is provided a shower head having a plurality of gas holes and a plurality of slots for passing electromagnetic waves in a position separated from the plurality of gas holes. There is provided an antenna for plasma generation.

As described above, according to the present invention, a plasma processing apparatus capable of supplying gas and electromagnetic waves and an antenna for generating plasma can be provided.

1 is a schematic longitudinal sectional view of a plasma processing apparatus according to a first embodiment.
Fig. 2 is a diagram showing the mechanism on the output side of the microwave according to the first embodiment.
3 is an enlarged view of the antenna for plasma generation according to the first embodiment.
4 is a bottom view of the shower head according to the first embodiment.
5 is a diagram illustrating a modification of the slot shape.
6 is an enlarged view of an antenna for plasma generation according to the second embodiment.
7 is an enlarged view of an antenna for plasma generation according to a modification.
8 is an enlarged view of an antenna for plasma generation according to the third embodiment.
9 is a diagram illustrating an antenna for plasma generation according to the fourth embodiment.
Fig. 10 is a diagram showing the mechanism on the output side of the microwave according to the fourth embodiment.
11 is a diagram showing a modification of the antenna for generating plasma according to the fourth embodiment.
12 is a diagram showing a modification of the antenna for generating plasma according to the fourth embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, embodiment of this invention is described in detail. In addition, in this specification and drawing, about the component which has a substantially identical functional structure, the same code | symbol is attached | subjected and overlapping description is abbreviate | omitted.

In addition, embodiments of the present invention are described in the following contents in the order of the first to fourth embodiments.

≪ Embodiment 1 >

[Configuration of Plasma Processing Unit]

[Configuration of Plasma Generating Antenna]

[Modification of slots]

≪ Embodiment 2 >

[Configuration of Plasma Generating Antenna]

Third Embodiment

[Configuration of Plasma Generating Antenna]

<Fourth Embodiment>

[Configuration of Plasma Generating Antenna]

[Operation of Plasma Generating Antenna]

&Lt; Embodiment 1 >

[Configuration of Plasma Processing Unit]

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. 1 is a longitudinal sectional view schematically showing a plasma processing apparatus.

In the present embodiment, the plasma processing apparatus 10 will be described taking as an example an etching apparatus for performing an etching process as a plasma processing on the semiconductor wafer W (hereinafter referred to as wafer W). The plasma processing apparatus 10 has the processing container 100 which plasma-processes the wafer W in the airtight inside. The processing container 100 is formed in a cylindrical shape, for example, made of metal such as aluminum, and grounded.

The susceptor 105 which mounts the wafer W is provided in the bottom part of the processing container 100. The susceptor 105 is formed of metal such as aluminum, is supported by the support member 115 via the insulator 110, and is provided at the bottom of the processing container 100. As a result, the susceptor 105 is in an electrically floating state. As a material of the susceptor 105 and the support member 115, aluminum etc. which anodized (anodic oxidation) the surface was mentioned.

The susceptor 105 is connected to a high frequency power supply 125 for bias via the matching unit 120. The high frequency power supply 125 applies the high frequency power for bias to the susceptor 105, and the ion in plasma enters into the wafer W side by this. Although not shown, the susceptor 105 has an electrostatic chuck for electrostatically adsorbing 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 W. Lifting pins and the like that may be lifted and lowered during transport may be provided.

An exhaust port 130 is formed 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 vacuum degree. A carry-in and outlet 140 is formed in the side wall of the processing container 100, and the wafer W is carried in and out by opening and closing the gate valve 145 which can open and close the carry-in and outlet 140.

Above the susceptor 105, a plasma generating antenna 200 (hereinafter referred to as antenna 200) capable of supplying electromagnetic waves (here, microwaves) is provided while supplying gas. The antenna 200 is provided in the opening part of the cover body 150. As a result, a plasma space U is formed between the susceptor 105 and the antenna 200. On the upper part of the antenna 200, a microwave transmitting mechanism 400 as an electromagnetic wave transmitting mechanism for transmitting microwaves is connected to transmit the microwaves output from the microwave output unit 300 to the antenna 200.

The control apparatus 500 controls DC voltage etc. which are applied to the antenna 200 as mentioned later. The control device 500 has 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. In addition, the instruction | command to the control apparatus 500 is executed by the CPU (not shown) which runs a dedicated control device or a program. The recipe in which the process conditions are set is stored in advance in a ROM or a nonvolatile memory (both not shown), and the CPU reads out and executes the recipe conditions from these memories.

With reference to FIG. 2, the structure of the microwave output part 300 and the microwave transmission mechanism 400 is demonstrated. 2, the internal structure of the microwave output part 300 is shown. 2, the internal structure of the microwave transmission mechanism 400 is shown.

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 with frequencies of 2.45 GHz, 8.35 GHz, 5.8 GHz, 1.98 GHz and the like. The microwave power source 305 is an example of an electromagnetic wave source, and outputs electromagnetic waves of a microwave band. The electromagnetic wave source is not limited to microwaves, but is a power source for outputting electromagnetic waves from the RF band of 100 MHz to the microwave band of 3 GHz. The microwave oscillator 310, for example, PLL oscillates microwaves of a predetermined frequency of 2.45 GHz. The amplifier 315 amplifies the oscillated microwaves.

The microwave transmission mechanism 400 has an antenna module 410 and a microwave introduction mechanism 450. The antenna module 410 has a phaser 412, a variable gain amplifier 414, a main amplifier 416, and an isolator 418, and the microwave introduction mechanism 450 receives the microwaves output from the microwave output unit 300. To send.

The phaser 412 is configured to change the phase of the microwave by a slug tuner and can modulate the radiation characteristics by adjusting it. According to this, the directivity can be controlled to change the plasma distribution. In addition, when the modulation of the radiation characteristic is not necessary, the phase shifter 412 need not be provided.

The variable gain amplifier 414 adjusts the power level of the microwaves 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 have an input matching circuit, a semiconductor amplifying element, an output matching circuit and a high Q resonant circuit (not shown).

The isolator 418 separates the reflected waves of the microwaves reflected from the antenna 200 and returned to the main amplifier 416 and includes a circulator and a dummy rod (coaxial terminator). The circulator guides the microwaves reflected by the antenna 200 to the dummy rod, and the dummy rod converts the reflected waves of the microwaves guided by the circulator into heat.

[Configuration of Plasma Generating Antenna]

Next, the configuration of the microwave introduction mechanism 450 and the plasma generating antenna 200 according to the first embodiment will be described with reference to FIG. 3. 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 has a coaxial tube 455 and a slow wave plate 480. The coaxial tube 455 has a coaxial waveguide formed of a cylindrical outer conductor 455a and a rod-shaped inner conductor 455b provided at the center thereof. An antenna 200 is installed at the lower end of the coaxial tube 455 via the slow wave plate 480. In the coaxial pipe 455, the inner conductor 455b is on the power supply side, and the outer conductor 455a is on the ground side. The coaxial pipe 455 is provided with a tuner 470. The tuner 470 has two slugs 470a and constitutes a slug tuner. The slug 470a is comprised as a plate-shaped body of a dielectric member, and is provided in the annular shape between the inner conductor 455b of the coaxial pipe 455, and the outer conductor 455a. The tuner 470 adjusts the impedance by moving the slug 470a up and down by an actuator (not shown) based on the command from the control unit 505. The control unit 505 adjusts the impedance so as to have a characteristic impedance of 50 Ω, for example, at the end of the coaxial tube 455.

The slow wave plate 480 is provided adjacent to the lower surface of the coaxial pipe 455. The slow wave plate 480 is formed of a disk-shaped dielectric member. The slow wave plate 480 transmits the microwaves transmitted from the coaxial tube 455 and guides them 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 DC applying 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 larger in diameter than 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 the surface wave to the exposed lower surface. Here, the metal surface of the shower head 210 is exposed to the plasma space U side. The surface wave propagating on the exposed lower surface is called a metal surface wave hereinafter.

The shower head 210 has a plurality of gas holes 215 and a plurality of slots 220 through which microwaves are passed at positions separated from the gas holes 215. The gas path 225 is formed in the shower head 210 in the radial direction of the shower head 210 through the side surface. Gas is supplied from the gas supply source 600 (see FIG. 1), flows from the gas path 225 into the plurality of gas holes 215 through the gas supply pipe 605, and from each gas hole 215 into the processing vessel. Is introduced. The surface exposed to the plasma side of the shower head 210 is covered with, for example, a film of alumina (Al ₂ O ₃ ) or yttria (Y ₂ O ₃ ) so that the conductor surface is not exposed to the plasma space side. I do not. The coating 290 is formed with openings communicating with the plurality of slots 220 and the plurality of gas holes 215.

The shower head 210 is formed with a cooling path (not shown) to cool the shower head 210. Since the shower head 210 is a conductor having high electrical conductivity, it is possible to efficiently dissipate heat from the slot 220 which is a microwave transmission path to the processing container body side.

The plurality of slots 220 are formed at positions separated from the gas path 225 and the plurality of gas holes 215, which are gas supply paths, and penetrate 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 transmits the coaxial tube 455, passes through the slow wave plate 480, and passes through the plurality of slots 220 to be radiated into the plasma space U.

4 is a diagram illustrating a surface (lower surface) exposed to the plasma space U of the shower head 210. The plurality of gas holes 215 are arranged substantially equally. The gas holes 215 are formed on the outer circumferential side and the inner circumferential 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 in which 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 formed on the inner circumferential side of the slot 220. have. Thus, slot 220 requires at least one compartment for passing gas path 225. Therefore, in this embodiment, although the slot 220 is four, it is not limited to this, What is necessary is just to have at least one partition part.

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

The gas hole 215 is a narrow hole so that microwaves radiated in the plasma space U may not be mixed inside the gas hole 215. In addition, the slot 220 and the gas hole 215 are completely separated in the shower head 210. Thereby, abnormal discharge in the gas path 225 and the gas hole 215 can be prevented.

3 again, the O-ring 485 and the 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 is installed from the microwave transmission mechanism 400 installed on the atmosphere side. ) And the inside of the processing container 100 are 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.

As in the present embodiment, when the shower head 210 is a conductor, a DC voltage (direct current voltage) may be applied to the shower head 210. Specifically, according to the instruction of the control unit 505, the DC voltage output from the DC power supply 255 is supplied to the DC applying mechanism 250. The DC applying mechanism 250 has a DC electrode 260, an insulating member 265, and an insulating sheet 270. The DC electrode 260 has a tubular conductor 260a and is connected to the shower head 210 via the tubular conductor 260a, thereby applying a DC voltage to the shower head 210. . The DC electrode 260 is screwed to the shower head 210 by an insulated socket (not shown) provided at the lower end of the tubular conductor 260a.

The DC electrode 260 is close to the outer conductor 455a and the lid 150 of the coaxial tube 455. Therefore, in order to DC-insulate the DC electrode 260, the coaxial tube 455, and the DC electrode 260 and the cover body 150, the DC electrode 260 is covered with the insulating member 265, and the DC electrode 260 ) And the coaxial tube 455, the DC electrode 260, and the lid 150. In addition, between the shower head 210 and the coaxial tube 455 and the shower head in order to DC-insulate the shower head 210 and the coaxial tube 455 and the shower head 210 and the cover body 150. An insulating sheet 270 is interposed between the 210 and the lid 150. In this way, by DC-insulating the processing container 100, the DC voltage is applied only to the shower head 210, so that the member on which the DC voltage is applied can be reduced as much as possible. In addition, when the shower head 210 is formed of an insulator, a DC voltage cannot be applied to the shower head 210. In this case, however, the same effect can be expected by applying an RF voltage.

As described above, according to the plasma processing apparatus 10 according to the present embodiment, a plurality of microwaves introduced from the coaxial tube 455 pass through the slow wave plate 480 and pass through the shower head 210. It is radiated into the plasma space U through the slot 220. At this time, standing waves (metal surface waves) having a wavelength characterized by a dispersion relationship are generated on the surface of the shower head 210 with the plasma sheath as boundary conditions, and are absorbed by the surface wave plasma. Gas supplied from the gas source 600 is also introduced into the plasma space U through the shower head 210. The introduced gas is excited by the 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 the etching process of the wafer W. Since the plasma has a low electron temperature, the wafer W is hardly damaged, and because of the high plasma density, the wafer W can be subjected to fine processing at high speed. In addition, by forming the shower head 210 as a conductor, processes such as reactive etching can be performed.

In the case of a general surface wave plasma source, a dielectric is installed in the lower part of the antenna slot, and when a shower head structure is fabricated from the dielectric, electromagnetic waves penetrate through the dielectric, so that there is a high possibility of abnormal discharges therein. It was very difficult to adopt the structure. For example, in an argon plasma, if a space of 10 mm is empty in the shower head space, if a voltage of about 120 volts is generated inside the shower head along the distance, abnormal discharge may occur inside the shower head at a pressure of 1 Torr. Is higher.

On the other hand, in the plasma processing apparatus 10 according to the present embodiment, since the shower head 210 is made of a conductor such as metal, electromagnetic waves do not enter the shower head 210, but the inside of the shower head 210 does not enter. There is no electric field. For this reason, abnormal discharge does not occur. Electromagnetic waves and gases are isolated inside the shower head 210 and flow into the processing vessel 100 so that they contact for the first time. 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 discharging gas uniformly to the shower head 210.

In addition, according to the plasma processing apparatus 10 according to the present exemplary embodiment, microwaves may be applied 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 microwaves are applied, surface waves propagate on the surface of the shower head 210. At this time, a sheath region is generated on the surface of the shower head 210, and a surface wave propagates through the sheath. The DC voltage controls the thickness of the sheath. For example, when the DC voltage is applied to the shower head 210, the sheath can be thickly controlled, and as a result, the propagation distance of the surface wave propagating through the surface of the shower head 210 can be lengthened. By operating the plasma sheath voltage by controlling the DC voltage in this manner, the propagation distance of the surface wave can be controlled to optimize the electron density distribution and the radical density distribution of the plasma.

[Modification of slots]

A modification of the slot formed in the antenna 200 will be described with reference to FIG. 5. The upper, middle, and lower sides of FIG. 5 show slots 220 having different shapes, respectively. The upper slot of FIG. 5 is partitioned into six slots 220. Each slot 220 is of the same shape, thick at the center and thin at both ends. Both ends of adjacent slots 220 face each other.

The center slot of FIG. 5 is divided into six slots 220. The center of each slot 220 is the same thickness as both ends. Each slot 220 is the same shape slightly curved and inclined in the oblique direction. Both ends of adjacent slots 220 face each other.

In the lower slot of FIG. 5, the outer circumferential side is divided into four slots 220, and the inner circumferential side also has a two-stage slot structure divided into four slots 220. Each slot 220 is an arc shape of the same thickness and is the same shape. The partition between the slots 220 on the outer circumference side is positioned at the center of the slot 220 on the inner circumference side, and the partition between slots 220 on the inner circumference side is disposed at the center of the slot 220 on the outer circumference side.

In all variations, the plurality of slots 220 are formed axially symmetric with respect to the central axis of the antenna 200. As a result, the microwaves can be uniformly radiated into the processing container 100. In addition, the plurality of slots 220 has at least one partition portion. Thereby, gas can be supplied from the gas hole 215 not shown in the outer peripheral side and the inner peripheral side of the slot 220. As shown in FIG.

&Lt; Embodiment 2 >

[Configuration of Plasma Generating Antenna]

Next, a configuration of a plasma generating antenna according to the second embodiment will be described with reference to FIG. 6. 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 may 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 dielectric members 220a are filled in the plurality of slots 220 according to the second embodiment. As the dielectric member 220a, quartz or the like may be used. As a result, the plasma may be prevented from entering the slot 220.

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

<Variation example>

As a modification of the above embodiment, the shower head 210 is made of silicon. In this case, the silicon surface of the shower head 210 is exposed as it is, as shown in FIG. 7, without spraying or providing the top plate 700 to the shower head 210.

In the second embodiment and the modified example, microwaves may be applied 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 microwaves are applied, surface waves propagate on the surface of the shower head 210. At this time, a sheath region is generated on the surface of the shower head 210, and a surface wave propagates through the sheath. The DC voltage controls the thickness of this sheath. For example, when the DC voltage is applied to the shower head 210, the sheath can be thickly controlled, and as a result, the propagation distance of the surface wave propagating through the surface of the shower head 210 can be lengthened. In this way, by operating the plasma sheath voltage by the control of the DC voltage, the propagation distance of the surface wave can be controlled and the electron temperature of the plasma can be optimized. In addition, in the case of a modification, when DC voltage is applied to the shower head 210, silicon is expelled from the shower head 210, thereby making it possible to increase the selectivity of etching.

Depending on the type of gas, pressure, and high frequency power during plasma generation, there is a fear that the plasma is excessively concentrated in the vicinity of the slot 220 and the plasma uniformity is disturbed. However, as described above, according to the plasma processing apparatus 10 according to the present embodiment, the dielectric member 220a is filled in the slot 220. For this reason, the plasma can be prevented from entering the slot 220. Thereby, the uniformity of plasma can be improved. In addition, the dielectric member 220a in the slot 220 can shorten the effective wavelength of the microwave passing through the slot. Thereby, the thickness of the shower head 210 can be made thin.

Third Embodiment

[Configuration of Plasma Generating Antenna]

Next, a configuration of the plasma generating antenna according to the third embodiment will be described with reference to FIG. 8. 8 is an enlarged view (left half) of the antenna for plasma generation according to the third embodiment. The plasma generating antenna 200 according to the third embodiment may 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 210 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. In addition, the second gas path 225b is connected to the gas supply pipe 605b. The desired gas 1 is supplied from the gas supply source 600 (refer to FIG. 1), flows into the plurality of gas holes 215 from the gas path 225a through the gas supply pipe 605a, and each gas hole 215. Is introduced into the processing vessel. The desired gas 2 is supplied from the gas supply source 600 (refer to FIG. 1), flows from the gas path 225b into the other plurality of gas holes 215 through the gas supply pipe 605b, and each gas hole 215. ) Is introduced into the processing vessel. As a result, different kinds of gases can be introduced alternately 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 formed in the shower head 210, whereby the flow of gas of two systems is controlled. To control. Gas is supplied from each shower head to the processing container 100, and it mixes in the space in a processing container, and can react two or more types of gas (post mix). According to this, the gas introduction position can be optimized according to the kind of gas, and a desired plasma can be generated. In addition, the gas path is not limited to two systems and may be divided into three or more gas paths which can be supplied separately without mixing three or more types of gases.

<Fourth Embodiment>

[Configuration of Plasma Generating Antenna]

Next, a configuration of the antenna for generating plasma according to the fourth embodiment will be described with reference to FIGS. 9 and 10. 9 is a diagram showing an antenna portion of the plasma processing apparatus according to the fourth embodiment. In FIG. 9, a 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. 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, description thereof is omitted here.

In the plasma processing apparatus 10 according to the fourth embodiment, the microwaves are output from the microwave power source 305 shown in the microwave output unit 300 in FIG. 10 and are distributed through the microwave oscillator 310 and the amplifier 315. Dispensed at 320.

Specifically, the microwave oscillator 310 PLL oscillates microwaves of a predetermined frequency, for example, 2.45 GHz. The amplifier 315 amplifies the oscillated microwaves. The distributor 320 distributes the amplified microwaves in plural. The distributor 320 distributes the microwaves amplified by the amplifier 315 while making impedance matching between the input side and the output side so that the microwaves are 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 has three antenna modules 410 for transmitting microwaves distributed by the distributor 320. Each antenna module 410 radiates microwaves from the coaxial tube 455 connected to each antenna module 410 into the processing container 100, and spatially synthesizes the microwaves therein. Therefore, the isolator 418 may be small and can be provided adjacent to the main amplifier 416.

The phaser 412 of each antenna module 410 is configured to change the phase of the microwave by a slug tuner, and can modulate the radiation characteristics by adjusting it. For example, by adjusting the phase for each antenna module 410, the polarization can be obtained by changing the plasma distribution by controlling the directivity, or by shifting the phase by 90 degrees from the neighboring antenna module 410. In addition, when the modulation of the radiation characteristic is not necessary, the phase shifter 412 need not be provided.

The variable gain amplifier 414 adjusts the power level of the microwaves input to the main amplifier 416, and adjusts the gaps of the individual antenna modules 410 and the plasma intensity. By varying the variable gain amplifier 414 for each antenna module 410, a distribution can be generated in the generated plasma.

The main amplifier 416 constitutes a solid state amplifier. The solid state amplifier can be configured to have an input matching circuit, a semiconductor amplifying element, an output matching circuit and a high Q resonant circuit (not shown).

The isolator 418 separates the reflected waves of the microwaves reflected from the antenna 200 toward the main amplifier 416 and has a circulator and a dummy rod (coaxial terminator). The circulator guides the microwaves reflected by the antenna 200 to the dummy rod, and the dummy rod converts the reflected waves of the microwaves induced 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 addition, in the present embodiment, three antennas 200 are individually provided on the cover body 150 and gas supply pipes 605 are formed in each of them, that is, the shower heads 210 are independently provided for each antenna 200. Is installed, it is easier to manufacture one shower head 210 for the plurality of antennas 200 than to install the plurality of shower heads 210 on the cover body 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 with respect to three antennas 200. In this case, one gas supply pipe 605 is formed for the common shower head 210. In addition, in FIG. 11, the basic structure of each antenna 200 is the same as the case shown in FIG. 9 except that the shower head 210 and the gas supply pipe 605 are common to the plurality of antennas 200. same.

 In addition, when a plurality of antennas 200 are commonly installed in one shower head 210, for example, independent annular gas paths 225 are formed concentrically around the central axis of the cover body 150, for example. You may form. In this case, each gas path 225 is isolated from each other. Specifically, for example, as shown in FIG. 12, two types of annular gas paths 225c and 225d are formed in the shower head 210. Gas supply pipes 605 are formed in the gas paths 225c and 225d, respectively. By doing in this way, the flow velocity of the gas introduce | transduced into the plasma space U, and the kind of gas introduce | transduced can be made to differ in the area | region of the center side of the showerhead 210, and the area | region of an outer side, respectively.

[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. 1. First, the wafer W is loaded into the processing container 100 and placed on the susceptor 105. Then, for example, plasma gas such as Ar gas is supplied from the gas supply source 600, and is introduced into the processing container 100 from the antenna 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 slow wave plate 480, and the slot 220. Plasma gas is excited by the electric field energy of microwaves, and a plasma is produced | generated.

Subsequently, an etching gas such as, for example, Cl ₂ gas is supplied from the gas supply source 600, and is introduced into the processing container 100 from the antenna 200 through a plurality of branched gas supply pipes 605. The etching gas is likewise excited and becomes a plasma. By the plasma of the process gas formed in this way, an etching process is performed to the wafer W, for example. Since the plasma has a low electron temperature, the wafer W is not damaged, and because of the 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 microwaves oscillated from the microwave oscillator 310 are amplified by the amplifier 315 and then distributed in plural by the distributor 320. The distributed microwaves are directed to the plurality of antenna modules 410. The plurality of microwaves distributed in this manner in each antenna module 410 are amplified separately in the main amplifier 416 constituting the 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. Microwaves transmitted through the slow wave plate 480 are radiated into the processing container from the slots 220 of the shower heads 210.

According to the above embodiments, it is possible to provide a plasma generating antenna 200 and a plasma processing apparatus 10 capable of supplying gas and electromagnetic waves separately.

As mentioned above, although the preferred embodiment of this invention was described in detail with reference to an accompanying drawing, this invention is not limited to this example. Those skilled in the art to which the present invention pertains can clearly conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood to belong to the technical scope of the invention.

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

The plasma generating antenna according to the present invention is not limited to the microwave plasma processing apparatus shown in the above embodiments, but is an inductively coupled plasma processing apparatus (ICP (Inductively Coupled Plasma)) or a capacitively coupled plasma processing apparatus. Etc. can be used for all plasma processing apparatus. The plasma processing apparatus according to the present invention is applicable to a process using surface wave plasma, a process using ICP plasma, and a process using CCP plasma.

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

In addition, the processing container of the plasma processing apparatus which concerns on this invention is not limited to a cylindrical shape, For example, a hexagonal shape or a square shape may be sufficient. Therefore, the to-be-processed object processed by the plasma processing apparatus which concerns on this invention is not limited to a disk shaped semiconductor wafer, For example, a rectangular substrate may be sufficient as it.

10: Plasma processing device
100 processing container
105: susceptor
150: cover body
200: antenna for plasma generation
210: Shower Head
215: gas hole
220: slot
225: gas path
225a: first gas path
225b: second gas path
250: DC approval mechanism
255: DC power
260 DC electrode
300: microwave output unit
400: microwave transmission mechanism
410: antenna module
450: microwave introduction mechanism
455: coaxial tube
455a: outer conductor
455b: inner conductor
480: slow wave plate
500 control device
505: control unit
600: gas source
U: plasma space

Claims (15)

A processing vessel in which plasma processing is performed,
A slow wave plate that transmits the supplied electromagnetic waves,
Plasma generating antenna having a shower head provided adjacent to the slow wave plate
And,
The shower head is formed of a conductor, a plurality of gas holes are formed, and has a plurality of slots for passing electromagnetic waves in a position separated from the plurality of gas holes
Plasma processing apparatus. The method of claim 1,
And said plasma processing apparatus comprises a plurality of said plasma generating antennas. The method of claim 2,
And the shower head propagates a surface wave to a surface exposed to the plasma space side. The method of claim 3, wherein
And the plurality of gas holes are formed in the shower head at the inside and the outside of the plurality of slots. The method of claim 4, wherein
And a gas path passing through a portion partitioning the plurality of slots and supplying gas to a plurality of gas holes formed inside the slot. The method of claim 5, wherein
The gas path is formed by dividing the gas path into a plurality of gas paths that can be supplied separately. The method according to claim 6,
And the gas path is formed concentrically with respect to the central axis of the shower head. 8. The method according to any one of claims 3 to 7,
And a plurality of said plasma generating antennas are each provided with an electromagnetic wave transmission mechanism for adjusting the electric power of said surface wave. The method according to any one of claims 1 to 7,
And a mechanism for applying a DC voltage to the shower head. The method of claim 9,
A mechanism for applying a DC voltage to the shower head has an insulating member between the coaxial tube and the plasma processing apparatus. The method according to any one of claims 1 to 7,
And the dielectric member is filled in the plurality of slots. The method according to any one of claims 1 to 7,
And the plurality of slots are formed in axisymmetric with respect to a central axis of the plasma generating antenna. The method according to any one of claims 1 to 7,
Spraying or a top plate is fixed to the surface of the shower head, the plasma processing apparatus, characterized in that the opening is formed in communication with the plurality of slots and the plurality of gas holes. The method according to any one of claims 1 to 7,
And the shower head is formed of silicon, and the surface of the shower head is exposed. And a shower head formed of a conductor, the shower head having a plurality of gas holes and a plurality of slots for passing electromagnetic waves in a position separated from the plurality of gas holes.

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