WO2007136043A1

WO2007136043A1 - Planar antenna member and plasma processing deice using same

Info

Publication number: WO2007136043A1
Application number: PCT/JP2007/060389
Authority: WO
Inventors: Caizhong Tian; Kinya Ota
Original assignee: Tokyo Electron Limited
Priority date: 2006-05-22
Filing date: 2007-05-21
Publication date: 2007-11-29
Also published as: JP4997826B2; TW200818309A; TWI392015B; JP2007311668A

Abstract

A planar antenna is provided to circumferentially rotate electric field radiated from microwave radiation holes around the planar antenna member to make plasma density uniform. The planar antenna member is comprised of an antenna plate (88) made of an electrically conductive metallic plate. A plurality of pairs of slots (100) are made in the antenna plate (88). The pair of slots (100) are two long groove-like microwave radiation slots (86) which are directed in different directions. Many of the pairs of slots (100) are disposed along a plurality of coaxial circles and the number of pairs of the slots (100) set around the most inner circle is not more than eight.

Description

Specification

Planar antenna member and plasma processing apparatus using the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a plasma processing apparatus used when processing is performed by applying plasma generated by a microwave or high frequency to a semiconductor wafer or the like, and a planar antenna member used therefor.

Background art

In recent years, with the increase in density and miniaturization of semiconductor products, there are cases where a plasma processing apparatus is used for processes such as film formation, etching, and ashing in the manufacturing process of semiconductor products. In particular, a plasma can be stably formed even in a high vacuum state where the pressure is relatively low, from about 0.1 lmTorr (13.3 mPa) to several lOmTorr (several Pa). A plasma processing apparatus for generating is used.

Such a plasma processing apparatus is disclosed in Patent Document 1, Patent Document 2, Patent Document 3, Patent Document 4, and the like. Here, for example, a general plasma processing apparatus using a microwave will be schematically described with reference to FIG. FIG. 7 is a schematic configuration diagram showing a conventional general plasma processing apparatus using microwaves.

In FIG. 7, the plasma processing apparatus 2 includes a processing container 4 that can be evacuated, and a mounting table 6 that is provided in the processing container 4 and on which a semiconductor wafer W is mounted. A ceiling plate 8 made of a disk-shaped aluminum nitride, quartz, or the like that transmits microwaves is provided in an airtight manner on the ceiling facing the substrate. A gas nozzle 9 for introducing a predetermined gas into the container is provided on the side wall of the processing container 4.

[0005] Then, a disk-shaped planar antenna member 10 having a thickness of about several millimeters on the top surface of the top plate 8, and an example for reducing the wavelength of the microwave in the radial direction of the planar antenna member 10 is dielectric. Slow wave material 12 consisting of body is installed. The planar antenna member 10 is formed with a large number of microwave radiation holes 14 made of, for example, long groove-like through holes. The microphone mouth wave radiation holes 14 are generally arranged concentrically or spirally. The central conductor 18 of the coaxial waveguide 16 is formed at the center of the planar antenna member 10. For example, a microwave of 2.45 GHz generated from the microwave generator 20 is converted into a predetermined vibration mode by the mode converter 22 and then guided.

[0006] Then, while propagating the microwaves radially in the radial direction of the antenna member 10, the microwaves are emitted from the microwave radiation holes 14 provided in the planar antenna member 10, and transmitted through the top plate 8, Microwave is introduced into the lower processing container 4. Next, plasma is generated in the processing space S in the processing container 4 by the microwave, and the semiconductor wafer W is subjected to predetermined plasma processing such as etching and film formation.

Patent Document 1: Japanese Patent Laid-Open No. 3-191073

Patent Document 2: JP-A-5-343334

Patent Document 3: Japanese Patent Laid-Open No. 9-181052

Patent Document 4: Japanese Patent Laid-Open No. 2003-332326

By the way, when performing the above plasma processing, it is necessary to perform a predetermined processing uniformly in the wafer surface. In this case, it is desirable that the plasma be set up uniformly in the in-plane direction of the processing space S. For this reason, in the conventional plasma processing apparatus, a large number of microwave radiation holes 14 are provided relatively uniformly on both the center side and the peripheral side of the planar antenna member 10, and the microwave radiation holes 14 provided in this way are provided in a relatively uniform manner. The microwaves are emitted toward the processing space S below.

[0008] The pitch of the microwave radiation holes 14 in the radial direction of the planar antenna member 10 is set to a value that allows microwaves propagating here to interfere with each other and efficiently radiate.

However, in the planar antenna member 10 as described above, when the microwave propagates the central conductor 18 side force in the radial direction of the planar antenna member 10, the planar antenna member 10 and A standing wave may occur in the slow wave material 12. For this reason, the strength of the electric field distribution of the microwave becomes fixed, and the electric field distribution of the microwave in the processing space S becomes non-uniform.

Disclosure of the invention

[0010] The present invention has been devised to pay attention to the above problems and to effectively solve them. An object of the present invention is to provide a planar antenna in which the plasma density is made uniform by rotating the electric field radiated from the microwave radiation hole in the circumferential direction of the planar antenna member. An object is to provide a member and a plasma processing apparatus using the same.

[0011] The present invention includes an antenna plate made of a conductive metal plate having a center, and is used for two long-groove microwave radiations that are directed in directions different from each other and close to each other. A plurality of slot pairs each including a slot are provided, and the plurality of slot pairs are arranged in multiple rows along a plurality of concentric circles on the antenna plate, and the number of slot pairs located in the innermost row is within eight or less. It is a planar antenna member characterized by becoming.

[0012] In this way, a plurality of sets of slot pairs are concentrically arranged, and the slot pair located at the innermost circumference is within eight sets, so that the electric field radiated from the microwave radiation hole can be reduced. The plasma density can be made uniform by rotating in the circumferential direction of the planar antenna member.

[0013] The present invention is characterized in that the slot pair located on the innermost periphery is spaced from the center side of the antenna plate by a wavelength of microwaves (one wavelength) propagating therethrough. It is a planar antenna member.

In the present invention, the distance between the concentric circles in which the slot pairs are arranged in the radial direction of the antenna plate is set to a length longer than λΖ2 of the wavelength of the microwaves propagating thereto. A planar antenna member characterized by the above.

[0015] The present invention provides the planar antenna member, wherein the slot has a width of 6 mm or more.

The present invention is characterized in that, among the slot pairs arranged concentrically, the number of pairs of slot pairs arranged in the outermost row is set within a range of 18 to 36 sets. It is a planar antenna member.

The present invention is the planar antenna member characterized in that the frequency of the microwave is 2.45 GHz.

[0018] The present invention provides a processing container having an opening in the ceiling so that the inside can be evacuated, a mounting table provided in the processing container for mounting an object to be processed, A top plate made of a dielectric material hermetically attached to the opening and transmitting electromagnetic waves, a planar antenna member provided on the top surface of the top plate, a microwave supply means connected to the planar antenna member, Gas introduction means for introducing a predetermined gas into the processing container, and the planar antenna member includes an antenna plate having a center and made of a conductive metal plate, and is connected to the antenna plate. A plurality of slot pairs each having two long groove-shaped slots for microwave radiation that are directed in different directions and are close to each other are provided, and the plurality of slot pairs are provided on the antenna plate along a plurality of concentric circles. The plasma processing apparatus is characterized in that it is arranged in multiple rows and the slot pairs located in the innermost row are within 8 pairs.

[0019] The present invention is characterized in that the slot pair located on the innermost circumference is spaced from the center side of the antenna plate by a wavelength of microwaves (one wavelength) propagating therethrough. It is a plasma processing apparatus.

In the present invention, the distance between the concentric circles in which the slot pairs are arranged in the radial direction of the antenna plate is set to a length larger than λ 2 of the wavelength of the microwaves propagating thereto. Is a plasma processing apparatus.

[0021] The present invention is the plasma processing apparatus, wherein the slot has a width of 6 mm or more.

The present invention is characterized in that, among the slot pairs arranged concentrically, the number of pairs of slot pairs arranged in the outermost row is set within a range of 18 to 36 sets. This is a plasma processing device.

[0023] The present invention is the plasma processing apparatus, wherein the microwave frequency is 2.45 GHz.

[0024] According to the planar antenna member and the plasma processing apparatus using the same according to the present invention, a plurality of pairs of slots are concentrically arranged, and the slot pair located on the innermost circumference is within eight pairs. Since it did in this way, the electric field radiated | emitted from a microwave radiation hole can be rotated to the circumferential direction of a planar antenna member, and a plasma density can be made uniform.

Brief Description of Drawings

FIG. 1 is a configuration diagram showing a plasma processing apparatus according to the present invention.

FIG. 2 is a plan view showing a planar antenna member.

FIG. 3 is an enlarged plan view for explaining a distance related to the slot of the planar antenna member.

FIG. 4 is a plan view showing another example of the arrangement of slot pairs.

[Figure 5] Figure 5 shows the number of innermost slot pairs of 8 when the microwave frequency is 2.45 GHz. It is a figure for demonstrating that electric field distribution rotates when it sets below.

FIGS. 6 (A), 6 (B), and 6 (C) are photographs showing the electric field distribution by simulation of the antenna plate of the planar antenna member of the device of the present invention.

FIG. 7 is a schematic configuration diagram showing a conventional general plasma processing apparatus using a microwave.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of a planar antenna member and a plasma processing apparatus using the same according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a plasma processing apparatus according to the present invention, FIG. 2 is a plan view showing a planar antenna member, and FIG. 3 is an enlarged plan view for explaining a distance related to a slot of the planar antenna member. Here, a case where a plasma etching process is performed as a plasma process will be described as an example.

As shown in the figure, a plasma processing apparatus 32 that performs an etching process using plasma includes, for example, a processing container 34 that is formed of a conductor such as aluminum on the side wall and the bottom and is formed into a cylindrical shape as a whole. ing. The inside of the processing vessel 34 is a sealed processing space S, and plasma is formed in the processing space S. This processing vessel 34 itself is grounded.

In the processing container 34, a mounting table 36 on which, for example, a semiconductor wafer W as a target object is mounted is accommodated on the upper surface. The mounting table 36 is formed in a substantially disc shape made flat by a ceramic such as alumina, and is erected from the bottom of the container via a column 38 made of, for example, aluminum.

[0030] A gate valve 40 that opens and closes when a wafer is loaded into and unloaded from the inside of the processing vessel 34 is provided on the side wall of the processing vessel 34. In addition, an exhaust port 42 is provided at the bottom of the container, and this exhaust port 42 is connected to an exhaust path 48 to which a pressure control valve 44 and a vacuum pump 46 are sequentially connected. Thus, the inside of the processing vessel 34 can be evacuated to a predetermined pressure.

[0031] Further, below the mounting table 36, there are provided a plurality of, for example, three lifting pins 50 (only two are shown in FIG. 1) for lifting and lowering the wafer W when it is loaded and unloaded. Elevating The pin 50 is moved up and down by an elevating rod 54 penetrating the bottom of the container through an extendable bellows 52. Further, the mounting table 36 is formed with a pin through hole 56 through which the elevating pin 50 is inserted. The entire mounting table 36 is made of a heat-resistant material, for example, a ceramic such as alumina, and a thin plate-like resistance heater 58 is embedded in the ceramic as a heating means. The resistance heater 58 is connected to a heater power source 62 through a wiring 60 that passes through the column 38.

In addition, a thin electrostatic chuck 66 having conductor wires 64 disposed in, for example, a mesh shape is provided on the upper surface side of the mounting table 36. The wafer W placed on the electrostatic chuck 66 is attracted by the electrostatic chuck 66 by electrostatic attraction force. The conductor wire 64 of the electrostatic chuck 66 is connected to a DC power source 70 via a wiring 68 in order to exert the electrostatic attraction force. The wiring 68 is connected to a bias high-frequency power source 72 in order to apply a bias high-frequency power of 13.56 MHz to the conductor wire 64 of the electrostatic chuck 66 at the time of etching.

[0033] Then, the ceiling portion of the processing vessel 34 is opened, and for example, a quartz plate, Al 2 O 3 or the like is used here.

A top plate 74 having transparency for microwaves made of a ceramic material is provided airtightly through a seal member 76 such as an O-ring. The thickness of the top plate 74 is set to about 20 mm, for example, in consideration of pressure resistance. A gas introducing means 78 for supplying necessary gas into the processing vessel 34 is provided on the side wall of the vessel directly below the top plate 74. In the present embodiment, the gas introduction means 78 has a gas nozzle 80 made of, for example, quartz provided through the side wall of the container, and various kinds of necessary gases can be supplied from the gas nozzle 80 while controlling the flow rate. It is summer. As the gas introduction means 78, for example, a shower head structure in which stone pipes having a large number of gas holes are assembled in a lattice shape may be employed.

[0034] Then, the present invention introduces a microwave for plasma generation into the processing space S of the processing vessel 34 through the top plate 74 in order to generate plasma in the processing vessel 34 on the upper surface of the top plate 74. The planar antenna member 82 characterized by the above is provided, and the planar antenna member 82 is connected to a microwave supply means 84 for supplying microwaves thereto. Specifically, the planar antenna member 82 has a disk-shaped antenna plate 88 made of a conductive metal plate in which a plurality of microwave radiation slots 86 are formed. This antenna The structure of the plate 88 will be described later.

The microwave supply means 84 has a slow wave material 90 disposed on the antenna plate 88. The slow wave material 90 is made of, for example, quartz, alumina, aluminum nitride or the like, and has a high dielectric constant characteristic in order to shorten the wavelength of the microphone mouth wave, and is preferably made of the same material as the top plate 74. The antenna plate 88 is configured as a bottom plate of a wave guide box 92 made of a conductive hollow cylindrical container covering the entire upper surface of the slow wave material 90, and is made to face the mounting table 36 in the processing container 34. Provided. A cooling jacket 94 is provided above the waveguide box 92 to flow a cooling medium in order to cool it.

The peripheral portions of the waveguide box 92 and the antenna plate 88 are both conducted to the processing vessel 34, and the outer tube 96 A of the coaxial waveguide 96 is connected to the center of the upper portion of the waveguide box 92. ing. This inner inner conductor 96B is connected to the center portion of the antenna plate 88 through, for example, a tapered (conical) connector 97 through the center through-hole of the slow wave member 90. The coaxial waveguide 96 is connected to a rectangular waveguide 99 via a mode converter 98, and the rectangular waveguide 99 is connected to a microwave generator 102 of 2.45 GHz, for example. Propagates microwaves to the antenna plate 88. Therefore, the microwave generator 102 and the antenna plate 88 are connected by the rectangular waveguide 99 and the coaxial waveguide 96 so as to propagate microwaves. A matching circuit 104 is provided in the middle of the rectangular waveguide 99 for impedance matching. Here, the frequency is not limited to 2.45 GHz, and other frequencies, for example, 8.35 GHz may be used.

Here, the antenna plate 88 of the planar antenna member 82 will be described in detail. The antenna plate 88 is a disc having a center C, and is made of a conductive material having a diameter of 400 to 500 mm and a thickness of 1 to several mm, for example, for a wafer having a size of 300 mm. For example, the surface is made of a copper plate or an aluminum plate plated with silver, and a plurality of microwave slots 86 each having, for example, a long groove-like through hole are formed in the disk.

[0038] Each of these slots 86 forms one set, that is, a slot pair 100, by two slots 86 arranged in a "c" shape. In this embodiment, the above-mentioned slot pair 100 consisting of two slots 86 is arranged in multiple rows L and L along a plurality of concentric circles, and the innermost circumference.

1 2

There are no more than 8 pairs of slots 100 located in row L. In Figure 2, the slot pair 1 00 is the slot pair 100A in the inner circumferential side (innermost circumferential side) row L and the outer row (second round) row L slot 100A.

1 2 From 100 lots vs. lots!

In the case shown in FIG. 2, in the innermost circumferential row L, five pairs of slots 100A force are arranged at equal intervals along the circumferential direction. Here, when the frequency of the microwave is 2.45 GHz, the number of slot pairs 100A located on the innermost circumferential side is within 8 pairs, in other words, the opening angle θ between the pair of slots 100A adjacent in the circumferential direction is θ. 1 is set to 45 degrees or more.

[0040] By setting the opening angle θ1 to 45 degrees or more in this way, it is possible to suppress the mutual interference of the radiated electric field between the innermost slot pair. As a result, the radiated electric field distribution can be rotated, and the plasma in the processing space S can be made uniform.

[0041] Further, in order to rotate the electric field distribution, it is necessary to provide at least two pairs of slots 100A in the innermost row L. Furthermore, it is arranged in row L on the second circumference (outermost circumference side) from the inside.

The number of pairs of slot pairs 100B to be set is set within a range of 18 to 36, and the slot pairs 100B are arranged at equal intervals along the circumferential direction of the antenna plate 88. In FIG. 2, 24 pairs (pieces) of slot pairs 100B in the second row L are arranged.

2

[0042] In addition, the number of slot pairs 100B in the row L (outermost circumference side) of row L takes the following matters into consideration.

2

To be determined.

'Emit all the microwaves propagated from the slot pair 100A in the innermost row L so that reflection does not occur.

• Maintain high plasma electron density ( ₈ X 10 ^{1 (>} Zcm ³ or more)).

• One innermost row L slot pair 100A and multiple second row (outermost side) row L slots

1 2 Make sure lots vs. 100B do not interfere!

Further, as shown in FIG. 3, the pair of slots 100A located in the innermost row L is the center side force of the antenna plate 88, and λ (1 (Wavelength) or more apart. Here, the wavelength is not the wavelength of the propagating microwave in vacuum, but the wavelength when the wavelength of the microwave is shortened by the slow wave material 90. Further, the distance HI between the center side of the antenna plate 88 and the slot pair 100A is equal to the outer circumference of the connector 97 at the center of the antenna plate 88 and the vertical 2 of each of the two slots 86 forming the slot pair 100A. This is the distance from the intersection P1 of the equipartition line. Therefore, the distance relationship is expressed as Further, it is preferable that the distance H2 between the center C of the connector 97 and the intersection point PI is set to a length of 1.5 λ or more.

[0045] Further, the distance between the slot pair 100 in the radial direction of the antenna plate 88, that is, the concentric circle R2 connecting the position Ρ2 of each slot pair 100B in the second circumference in the radial direction of the antenna plate 88, Difference in radius from concentric circle R1 that connects position P1 of each inner slot pair 100A Η3 (For the sake of simplicity, distance Η3 will be referred to as the innermost row L slot pair and the second row L The distance from the slot pair of

2

The length can be set to a length that is larger than の 2 or smaller than λΖ2. Here, in the case where the distance is Η3 / 2 (and an odd multiple thereof), the microwaves radiated from both slot pairs 100A and 100B are out of phase with each other and cancel each other out. Further, if the distance Η3 is smaller than λΖ2, abnormal discharge may occur, so the value of Η3 is preferably larger than λΖ2. Here, the positions Pl and Ρ2 are the intersections of the perpendicular bisectors of the two slots 86 constituting each slot pair 100A and 100B as described above.

[0046] Further, as described above, in the case of the planar antenna member 82 corresponding to the wafer having a diameter of 300 mm and the slow wave member 90 is quartz, the slot pair 100B in the row L in the second circumference is used. Is

2

It is preferable to position the antenna plate 88 within a range of 120 to 200 mm from the center of the antenna plate 88 (diameter force of about 08 mm).

[0047] The width 11 of all the slots 86 included in each of the slot pairs 100A and 100B is preferably set to 6 mm or more. This is because when the width 11 is smaller than 6 mm, abnormal discharge easily occurs here. In this case, the power supplied to the planar antenna member 82 is about 2000 to 4500 W (watts), and the abnormal discharge is likely to occur regardless of the microwave frequency when the width 11 is smaller than 6 mm. .

[0048] In the above embodiment, the slot pair 100 has two slots 86 arranged in a so-called "tapped shape" as an example. As shown, the slot pair 100 can be applied to a case where the two slots 86 are slightly separated and arranged in a so-called “T” shape. Even in this case, each distance H1-H3 Intersections Pl and P2 that define the vertical bisectors of the two slots 86 as shown in the figure.

[0049] Returning to Fig. 1, the overall operation of the plasma processing apparatus 32 configured as described above is controlled by the control means 120 made of, for example, a microcomputer. The computer program to be executed is stored in a storage medium 122 such as a floppy disk, a CD (Compact Disc), a flash memory or a node disk. Specifically, supply of each gas and flow control, supply of microwaves and high frequency, power control, control of process temperature and process pressure, and the like are performed according to commands from the control means 120.

Next, for example, an etching method performed using the plasma processing apparatus 32 configured as described above will be described.

First, the semiconductor wafer W is accommodated in the processing container 34 by the transfer arm (not shown) via the gate valve 40, and the wafer W is moved to the upper surface of the mounting table 36 by moving the lifting pins 50 up and down. The wafer W is mounted on the mounting surface, and the wafer W is electrostatically attracted by the electrostatic chuck 66. The wafer W is maintained at a predetermined process temperature by a resistance heater 58, and a predetermined gas such as C1 gas, O gas, and N gas, for example, a gas source (not shown) is set to a predetermined temperature.

2 2 2

The gas nozzle 80 of the gas introduction means 78 is supplied to the processing space S in the processing container 34 at a flow rate, and the pressure control valve 44 is controlled to maintain the processing container 34 at a predetermined process pressure.

At the same time, by driving the microwave generator 102 of the microwave supply means 84, the microwave generated by the microwave generator 102 is converted into the rectangular waveguide 99 and the coaxial waveguide 96. Then, it is supplied to the antenna plate 88 of the planar antenna member 82 to introduce the microwave whose wavelength is shortened by the retardation material 90 into the processing space S, thereby generating a plasma in the processing space S to generate a predetermined plasma. Etching process using is performed.

[0053] As described above, when microwaves are introduced from the slots 86 of the antenna plate 88 into the processing vessel 34, the gases CI, O, and N are converted into plasma by the microwaves and activated.

2 2 2

The etching target layer formed on the surface of the wafer W is etched and removed by the active species generated at this time. Then, each of the gases flows downward while being diffused substantially evenly around the mounting table 36, and is discharged from the exhaust path 48 through the exhaust port 42. In the etching process, the conductor wire 6 in the electrostatic chuck 66 from the high frequency power supply 72 for bias is used. A high frequency for bias is applied to 4 so that active species and the like are drawn into the wafer surface with good straightness so that the etching shape is not collapsed as much as possible.

Here, the 2.45 GHz microwave supplied through the connector 97 at the center of the antenna plate 88 is propagated radially from the center of the antenna plate 88 toward the periphery, and then A microwave is emitted from lot 86 toward processing space S below. Here, in the device of the present invention, the antenna plate 88 has slot pairs arranged in multiple rows L and L along a plurality of concentric circles, and

1 2

The number of pairs of slots 100A located in the innermost row L is reduced to 8 or less, and here 5 is set, so the electric field distribution force of microwaves radiated from each slot pair 100A and 100B The antenna plate 88 rotates around the center at a high speed.

[0055] In other words, if there are more than eight slot pairs 100A in the innermost row L, for example, there are about 12 to 20 slot pairs as in the antenna plate of the conventional device, the antenna plates 88 and A standing wave due to interference between the pair of slots is generated in the slow wave material 90, and the electric field distribution generated due to this is fixed without rotating, and thus the density of the plasma density is generated. However, in the case of the device of the present invention, the number of slot pairs 100A in the innermost circumferential row L is set to 8 or less, that is, the opening angle θ 1 between adjacent slot pairs 100A is π Ζ4 (angular velocity Therefore, the microwave that propagates the central force of the antenna plate 88 to the peripheral part is not a standing wave but a traveling wave. As a result, the electric field distribution of the microwave is as described above. Will rotate at high speed. Therefore, the plasma density in the processing space S can be made uniform.

FIG. 5 is a diagram for explaining that the electric field distribution rotates when the number of slot pairs 100A in the innermost row L is set to 8 or less when the microwave frequency is 2.45 GHz. It is. First, as shown in the figure, the antenna plate 88 is divided by the number of slot pairs 100A in the innermost row L as shown by the dotted line, and this division is made one sector. In this sector, microwaves propagate from the center of the antenna to the slot pair S1 → S2 → S3 → S4, and during this time, all of the microphone mouth wave power (energy) is radiated and no reflection occurs. To do. Here, the maximum number of slot pairs in the innermost row L is set to 8 because the opening angle θ 1 is required to be 45 degrees or more in order to suppress the mutual interference of the radiated electric field between the slot pairs. . One innermost The slot pair 100A in the circumferential row L does not interfere with the plurality of outermost row L slot pairs 100B.

1 2

It is necessary to make it. In other words, the number of slot pairs in the outermost row L is the original microwave transmission.

2

Propagation power of microwave power between slot pair S1 and S2 which is the carrying path The propagation amount between slot pair S5 belonging to a sector different from slot pair S1 is sufficiently large (at least 5 times or more) Set to a number. For this purpose, an opening between adjacent slot pairs in the outermost row L is adjacent.

2

The angle Θ 2 (see Fig. 2) must be 10 degrees or more, that is, above the logarithmic number of slots in the outermost row L

2

The limit is 36. Also, the lower limit of the number of 100B pairs of slots in the outermost row L is required.

2

In the case of the present application, the plasma electron density is 8 × 10 ^1G Zcm ³ or more, so 18 is required.

In FIG. 5, the slot pair 100A in the innermost row L and the slot pair 10 in the outermost row L

1 2

If the distance from 0B (corresponding to H3 in Fig. 3) is, for example, (5Z4) · λ, and the angle between the pair of slots on the outermost row L is 15 degrees, for example, the slot pair through which microwaves propagate The order of microwaves in S1, S2, S3, and S4 is S 1 = 0 degrees, S2 = 90 degrees, S3 = 105 degrees, S4 = 120 degrees, and the combined electric field radiated from these slot pair forces rotates in the circumferential direction of the antenna.

[0058] Further, the distance HI between the outer periphery of the connector 97 of the antenna plate 88 and the slot pair 100A in the innermost row L is set to a length of one wavelength or more, and the center C of the antenna plate 88 is Since the distance H2 between the slot pair 100A in the inner circumferential row L is set to a length of 1.5 λ or more, the above-mentioned microwave electric field distribution rotates more smoothly and at a higher speed, and the processing space The plasma density in S can be made more uniform.

[0059] <Evaluation results by simulation>

Here, since the antenna plate 88 of the planar antenna member 82 of the device of the present invention was evaluated by simulation, the evaluation result will be described. For comparison, the antenna plate of the conventional device was also evaluated.

[0060] The antenna plates are all sized to accommodate a 300 mm diameter wafer. FIG. 6 (A) shows a comparative example of the conventional apparatus, and FIGS. 6 (B) and 6 (C) show Examples 1 and 2 of the apparatus of the present invention, respectively. In each figure, a picture of the slot pattern and the electric field distribution is shown, and a schematic diagram of the electric field distribution is shown for easy understanding. In addition, the circumference of the microwave All wave numbers are 2.45GHz.

[0061] The antenna plate of the conventional device shown in Fig. 6 (A) is provided with two rows of slot pairs concentrically, with 20 slot pairs arranged on the innermost circumference, and on the second circumference. Has 36 slot pairs. In this case, a concentric fixed electric field distribution is formed, and since the electric field distribution is fixed, concentric shading is generated in the plasma density, which is not preferable.

On the other hand, in the first embodiment of the device of the present invention shown in FIG. 6 (B), two rows of slot pairs are provided concentrically, and three slot pairs are provided on the innermost circumference. In the second round, 24 slot pairs are arranged. In this case, the electric field distribution was formed in a spiral shape. However, it was confirmed that this electric field distribution was rotating in the circumferential direction at a high speed.

In the second embodiment of the device of the present invention shown in FIG. 6 (C), two rows of slot pairs are provided concentrically, and five slot pairs are arranged on the innermost periphery. On the second lap, 24 slot pairs are arranged. In this case, the electric field distribution is more uniform than when there are three pairs of slots on the innermost circumference, and no clear spiral shape is confirmed, but the overall strength of the electric field distribution is mixed, In addition, this electric field distribution was confirmed to rotate in the circumferential direction at high speed around the center of the slot plate.

[0064] In the above embodiment, the case where the slot pairs 100 are arranged in two concentric rows has been described as an example. However, the present invention is not limited to this, and the slot pairs 100 are concentric depending on the size of the antenna plate 88. Three or more rows may be arranged in a circle.

[0065] For example, when the material of the slow wave material 90 is alumina, the wavelength of the microwave in the slow wave material is considerably shortened compared to the case of quartz. It is possible to arrange three pairs of pairs. In this case, an intermediate slot pair (second row) is arranged between the innermost slot pair and the outermost (third row) slot pair. As described above, Pl, P2, and H1 to H3 are determined for the innermost slot pair and the second row slot pair. Also, let H4 be the distance between each slot pair in the second row and the slot pair in the third row. That is, H4 is the difference in radius between the concentric circles connecting P3 and the concentric circles connecting the positions P2 of each slot pair in the second row, where the position of each slot pair in the third row is P3 (not shown). It is. At this time, the relationship between H1-H4 and the microwave wavelength is Hl≥e, H2≥l. 5) H3> λ Ζ2 and H4> λ Ζ2. The number of slot pairs in each row is 2≤ the number of innermost slot pairs ≤ 8, 4≤ the number of slot pairs in the second row ≤ 18, 18 ≤ the number of slot pairs in the third row (outermost) Number ≤ 36. Note that it is possible to provide the second row of slot pairs in terms of space, but this need not be provided.

[0066] Further, here, the power described by taking plasma etching as an example of plasma processing is not limited to this, and the present invention is applied to all plasma processing such as plasma sputtering processing, plasma CVD processing, and plasma ashing processing. be able to.

[0067] Although a semiconductor wafer or an LCD substrate has been described as an example of the object to be processed here, the present invention is not limited thereto, and the present invention can also be applied to a glass substrate, a ceramic substrate, or the like.

Claims

The scope of the claims

[1] comprising an antenna plate having a center and made of a conductive metal plate,

The antenna plate is provided with a plurality of slot pairs each consisting of two slots for microwave radiation that are directed in different directions and close to each other,

The planar antenna member characterized in that the plurality of sets of slot pairs are arranged in multiple rows along a plurality of concentric circles on the antenna plate, and the number of slot pairs located in the innermost circumferential row is eight or less. .

[2] The slot pair located at the innermost circumference is spaced from the center side of the antenna plate by a wavelength of microwaves (one wavelength) propagating to the antenna plate or more. The planar antenna member according to 1.

[3] The distance between the concentric circles in which the slot pairs are arranged in the radial direction of the antenna plate is set to a length longer than λΖ2 of the wavelength of the microwave propagating therethrough. Item 2. The planar antenna member according to Item 1.

4. The planar antenna member according to claim 1, wherein the slot has a width of 6 mm or more.

5. The number of pairs of slot pairs arranged in the outermost row among the slot pairs arranged concentrically is set within a range of 18 to 36 sets. Planar antenna member.

6. The planar antenna member according to claim 1, wherein the frequency of the microwave is 2.45 GHz.

[7] A processing vessel having an opening in the ceiling and evacuated inside,

A mounting table provided in the processing container for mounting the object to be processed;

A top plate made of a dielectric that is hermetically attached to the opening of the ceiling portion and transmits electromagnetic waves; and a planar antenna member provided on an upper surface of the top plate;

Microwave supply means connected to the planar antenna member;

Gas introduction means for introducing a predetermined gas into the processing container;

With

The planar antenna member is An antenna plate having a center and made of a conductive metal plate;

A plurality of sets of slot pairs are arranged in a plurality of rows along a plurality of concentric circles on the antenna plate, and the number of slot pairs located in the innermost row is within 8 sets. .

[8] The slot pair located on the innermost periphery is spaced from the center side of the antenna plate by a wavelength of one wavelength or more of the microwaves propagating to the antenna plate. 7. The plasma processing apparatus described in 7.

[9] The distance between the concentric circles in which the slot pairs are arranged in the radial direction of the antenna plate is set to a length longer than λΖ2 of the wavelength of the microwave propagating therethrough. Item 8. The plasma processing apparatus according to Item 7.

10. The plasma processing apparatus according to claim 7, wherein the slot has a width of 6 mm or more.

[11] The number of sets of slot pairs arranged in the outermost row among the slot pairs arranged concentrically is set within a range of 18 to 36 sets. Plasma processing equipment.

12. The plasma processing apparatus according to claim 7, wherein the frequency of the microwave is 2.45 GHz.