WO2010086950A1

WO2010086950A1 - Microwave plasma processing apparatus, dielectric board provided with slot board for microwave plasma processing apparatus, and method for manufacturing dielectric board

Info

Publication number: WO2010086950A1
Application number: PCT/JP2009/007244
Authority: WO
Inventors: 石橋清隆; 桶作正広
Original assignee: 東京エレクトロン株式会社
Priority date: 2009-01-30
Filing date: 2009-12-25
Publication date: 2010-08-05
Also published as: JP2010177065A; TW201119521A

Abstract

Provided is a microwave plasma processing apparatus which prevents a slot board from wearing and a conductive film as the slot board from peeling from a dielectric board even when the slot board and a dielectric window are thermally expanded. A dielectric board (22) is provided with a protruding section (22c) which protrudes to the inside of a slot (23a) of a slot board (23). Then, the surface of the protruding section (22c) of the dielectric board (22) is protruded outward from the surface of a dielectric window (12) toward the dielectric window (12). When the slot board (23) is directly in contact with the dielectric window (12), an elongation quantity difference is generated due to the difference between the thermal expansion coefficient of the slot board (23) and that of the dielectric window (12). By bringing the protruding section (22c) of the dielectric board (22) into contact with the dielectric window (12) and not bringing the slot board (23) into contact with the dielectric window (12), the slot board (23) is prevented from wearing and the conductive film as the slot board (23) is prevented from peeling from the dielectric board (22), even when the slot board (23) and the dielectric window (12) are thermally expanded.

Description

Microwave plasma processing apparatus, dielectric plate with slot plate for microwave plasma processing apparatus, and manufacturing method thereof

The present invention relates to a microwave plasma processing apparatus that performs plasma processing on an object to be processed such as a semiconductor wafer, a liquid crystal substrate, and an organic EL element with plasma generated using microwaves.

Plasma treatment is widely used in processes such as etching and thin film deposition in semiconductor manufacturing processes. In recent years, the process rules (IC line width) of semiconductors constituting an LSI have been increasingly miniaturized from the viewpoint of high integration, high speed, and low power consumption of the LSI. When the distance between the wirings is shortened, the conventional interlayer insulating film cannot be insulated, and there is a possibility of interfering with a signal of an adjacent wiring. In order to solve this interference, an insulating film having a low dielectric constant (Low-k) is required. However, the parallel plate type and inductively coupled type plasma processing apparatuses that have been widely used conventionally have a problem of damaging the insulating film having a low dielectric constant due to the high electron temperature. For example, when a CF film containing carbon and fluorine, which is known as an insulating film having a low dielectric constant, is used, the dielectric constant increases due to plasma processing damage.

Furthermore, the size of semiconductor wafers has also increased in size, and accordingly, it has been demanded that semiconductor wafers having a large diameter be uniformly processed without being biased. However, in a parallel plate type or inductively coupled plasma processing apparatus, since a region having a high plasma density is limited, it is difficult to uniformly plasma process a large-diameter wafer.

Therefore, in recent years, a microwave plasma processing apparatus using RLSA (Radial Line Slot Slot Antenna) capable of uniformly forming a high density and low electron temperature plasma has attracted attention. This microwave plasma treatment apparatus radiates microwaves into a processing container from a planar microwave antenna having a number of slots arranged so as to generate uniform microwaves. The gas is ionized to excite the plasma. According to the microwave plasma processing apparatus, since a high plasma density can be realized in a wide region directly under the antenna, it is possible to perform uniform plasma processing in a short time. Moreover, since plasma having a low electron temperature can be generated, there is an advantage that damage to the substrate to be processed can be reduced.

As shown in FIG. 1, in the microwave plasma processing apparatus, the opening of the ceiling portion of the processing container 1 is closed by a dielectric window 2. A microwave antenna 3 is placed on the dielectric window 2. The microwave propagated through the coaxial waveguide 4 having an annular cross section of the coaxial waveguide composed of the inner waveguide and the outer waveguide propagates in the radial direction through the disk-shaped dielectric plate 6. The microwave whose wavelength is compressed in the dielectric plate 6 and resonates passes through the slot of the slot plate 7 made of a conductive material, and is radiated into the processing container 1 through the dielectric window 2.

When the plasma gas in the processing container 1 is excited, heat is transferred to the microwave antenna 3 through the dielectric window 2. Since the thermal expansion coefficient of the slot plate 7 made of a conductive material is larger than the thermal expansion coefficient of the dielectric plate 6 made of a dielectric, the slot plate 7 extends larger than the dielectric plate 6 and this is shown in FIG. As described above, the slot plate 7 is bent or deformed. When a gap is generated between the dielectric plate 6 and the slot plate 7, the reflected wave increases, so that the microwave propagation characteristics change. In order to prevent a gap from being generated between the dielectric plate 6 and the slot plate 7 and to keep the propagation of microwaves constant, Patent Document 1 discloses a conductive film constituting the slot plate 7 as a dielectric plate 6. A technique for plating on a metal is disclosed. By plating the conductive film on the dielectric plate 6, the dielectric plate 6 and the conductive film can be thermally expanded together, and the generation of a gap between them can be prevented.

JP 2002-355550 A

Not only the gap between the dielectric plate 6 and the conductive film, but also the gap between the conductive film and the dielectric window causes machine differences (differences between apparatuses performing the same process). In order to prevent a gap from being formed between the conductive film and the dielectric window, the dielectric plate plated with the conductive film is pressed against the dielectric window from above by a strong force. The thermal expansion coefficient of the conductive film made of the conductive material is different from the thermal expansion coefficient of the dielectric window made of the dielectric. For this reason, when the conductive film and the dielectric window are thermally expanded, a relative shift in the amount of elongation in the horizontal direction occurs between them.

If the conductive film and the dielectric window are in close contact with each other with a strong force and thermally expanded, wear due to thermal expansion becomes severe. In addition to rubbing the contact surface, the plated conductive film may even peel from the dielectric plate.

Therefore, the present invention provides a microwave plasma processing apparatus capable of preventing the slot plate from being worn or the conductive film as the slot plate from being peeled off from the dielectric plate even if the slot plate and the dielectric window are thermally expanded, It is an object of the present invention to provide a dielectric plate with a slot plate for a microwave plasma processing apparatus and a manufacturing method thereof.

In order to solve the above-described problems, an embodiment of the present invention provides a processing container in which a ceiling portion is defined by a dielectric window, a gas exhaust system that decompresses the processing container, and a gas that supplies plasma gas to the processing container A microwave plasma processing apparatus comprising: a supply unit; and a microwave antenna that is placed on the dielectric window of the processing container and that excites plasma gas in the processing container. A dielectric plate that propagates a wave and compresses the wavelength of the microwave, and a slot plate that has a slot that transmits the microwave, and the dielectric plate has a protrusion protruding into the slot of the slot plate. A microwave plasma processing apparatus, wherein the surface of the convex portion of the dielectric plate protrudes outward from the surface of the slot plate toward the dielectric window. .

Another aspect of the present invention is a dielectric plate with a slot plate for a microwave plasma processing apparatus that plasma-processes an object to be processed by plasma generated using microwaves, and has a slot that transmits microwaves. A microwave plasma processing apparatus comprising: a slot plate; and a dielectric plate having a convex portion protruding into the slot of the slot plate, and a surface of the convex portion protruding outward from a surface of the slot plate. It is a dielectric plate with a slot plate.

Still another aspect of the present invention is a method of manufacturing a dielectric plate with a slot plate for a microwave plasma processing apparatus for plasma processing a target object with plasma generated using a microwave, the microplate of the slot plate Removing the remaining part of the dielectric plate while leaving the part corresponding to the slot so that the part corresponding to the slot through which the wave is transmitted becomes a convex part, and the part other than the convex part of the dielectric plate Forming a slot plate made of a conductive film so that the surface of the convex portion protrudes outward from the surface of the slot plate, and a method of manufacturing a dielectric plate with a slot plate for a microwave plasma processing apparatus It is.

¡When the slot plate is brought into direct contact with the dielectric window, the amount of elongation shifts due to the difference in thermal expansion coefficient between the slot plate and the dielectric window. According to the present invention, since the convex portion of the dielectric protrudes from the slot of the slot plate, the convex portion can be brought into contact with the dielectric window, and the slot plate can not be brought into direct contact with the dielectric window. Therefore, even if the slot plate and the dielectric window are thermally expanded, it is possible to prevent the slot plate from being worn and the conductive film as the slot plate from being peeled off from the dielectric plate.

Sectional view of a conventional microwave plasma processing apparatus Sectional drawing which shows the deformation | transformation of the slot plate of the conventional microwave plasma processing apparatus Sectional drawing of the microwave plasma processing apparatus of one Embodiment of this invention Detailed view of dielectric plate on which conductive film is formed Sectional drawing which shows the convex part of the dielectric material protruding from a conductive film Sectional drawing which shows the contact state of a dielectric material window and an electrically conductive film ((a) in the figure shows the dielectric plate of this embodiment, (b) shows the conventional dielectric plate in the figure) Process diagrams of a method for manufacturing a dielectric plate on which a conductive film is formed ((a) in the figure is a method for manufacturing a dielectric plate of the present embodiment, and (b) in the figure is a method for manufacturing a conventional dielectric plate) is there) Sectional view showing an example of plating Diagram showing electrical contact between coaxial waveguide and upper and lower conductive films on dielectric plate Diagram showing electrical contact between inner conductor of coaxial waveguide and conductive film on lower surface of dielectric plate The figure which shows the electrical contact with the electrically conductive film of the lower surface of a cooling plate and a dielectric plate Sectional drawing which shows the other example of electric power feeding means Sectional drawing which shows the example which interposed the buffer sheet between the convex part of the dielectric material plate, and the dielectric material window Sectional drawing which shows the example which interposed the buffer sheet between the electrically conductive film and the dielectric material window

Hereinafter, an embodiment of a microwave plasma processing apparatus of the present invention will be described with reference to the accompanying drawings. FIG. 3 shows an overall configuration diagram of the microwave plasma processing apparatus.

The microwave plasma processing apparatus includes a processing container 11 partitioned by an outer wall, and a holding table 16 provided in the processing container 11 and made of AlN or Al2O3 for holding a substrate to be processed by an electrostatic chuck. In the processing container 11, exhaust ports are formed evenly in the circumferential direction in an annular space surrounding the holding table 16. The processing container 11 is evacuated and decompressed by a vacuum pump through an exhaust port.

The processing container 11 is made of Al, preferably stainless steel containing Al, and a protective film made of aluminum oxide is formed on the inner wall surface by oxidation treatment. A dielectric window 12 made of a dielectric material such as Al ₂ O ₃ or quartz is provided as a part of the outer wall of the ceiling of the processing container 11. The dielectric window 12 is attached to the side wall of the processing container 11 via a seal ring 13. The dielectric window 12 is fixed to the processing container 11 by a dielectric window pressing ring 14 attached to the upper part of the side wall of the processing container 11. The dielectric window pressing ring 14 is made of Al or stainless steel containing Al, like the processing container 11.

An annular gas supply unit 15 for supplying plasma gas into the processing container 11 is provided on the side wall of the processing container 11. A gas supply system is connected to the gas supply unit 15. A plasma excitation gas such as Ar gas or Kr gas, or a processing gas corresponding to the type of plasma processing is supplied from the gas supply unit to the processing vessel 11. Such plasma treatment includes plasma oxidation treatment, plasma nitridation treatment, plasma oxynitridation treatment, plasma CVD treatment and the like. A fluorocarbon gas such as C ₄ F ₈ , C ₅ F _8, or C ₄ F ₆ or an etching gas such as an F-based or Cl-based gas is supplied from a gas supply unit, and a high-frequency voltage is supplied from a high-frequency power source to the holding table 16. It is also possible to perform reactive ion etching on the substrate to be processed by applying.

On the side wall of the processing container 11, a loading / unloading port (not shown) for loading and unloading the substrate to be processed is provided. The carry-in / out port is opened and closed by a gate valve.

On the dielectric window 12, a planar microwave antenna 18 for exciting the plasma gas in the processing vessel 11 is placed. The microwave antenna 18 includes a coaxial waveguide 19 that propagates microwaves in the vertical direction in a coaxial mode, and a disk-shaped dielectric that propagates microwaves that have passed through the coaxial waveguide 20 of the coaxial waveguide 19 in the radial direction. It includes a plate 22, a conductive film 23 as a slot plate having a slot through which microwaves are transmitted, and a cooling plate 24 provided on the upper surface of the dielectric plate 22 to cool the dielectric plate 22.

The coaxial waveguide 19 as a power feeding means for feeding microwaves includes an inner conductor 19a extending in the vertical direction and a cylindrical outer conductor 19b surrounding the inner conductor 19a. A coaxial waveguide 20 having an annular cross section is formed between the inner conductor 19a and the outer conductor 19b. The upper end portion of the coaxial waveguide 19 is connected to a rectangular waveguide 21 (see FIG. 1) extending in the horizontal direction. A conical mode converter 25 (see FIG. 1) is provided at the connection between the rectangular waveguide 21 and the coaxial waveguide 19. The rectangular waveguide 21 is connected to a microwave generator such as a magnetron through a matching unit. The microwave generator generates microwaves with frequencies of 2.45 GHz, 8.35 GHz, 1.98 GHz, and the like, for example. The microwave propagating through the rectangular waveguide 21 is converted into the coaxial mode by the mode converter 25 and propagates in the vertical direction through the coaxial waveguide 20 (see FIG. 3). The matching unit propagates the microwave generated from the microwave generator to the dielectric plate 22 via the rectangular waveguide 21 and the coaxial waveguide 20.

The dielectric plate 22 is made of a dielectric such as Al ₂ O ₃ or quartz. A conductive film 23 as a slot plate is formed on the lower surface of the dielectric plate 22. In this embodiment, the conductive film 23 is formed not only on the lower surface of the dielectric plate 22 but also on the upper surface and the outer peripheral surface. Microwaves are electromagnetic waves that propagate while the electric and magnetic fields change very quickly. Microwaves that hit the metal surface hardly penetrate into the metal, cause an electric current to flow on the very surface (skin depth), and are mostly reflected. For this reason, the microwave irradiated to the dielectric plate 22 from the coaxial waveguide 20 propagates in the dielectric plate 22 in the radial direction while being reflected by the conductive film 23 formed on the upper and lower surfaces of the dielectric plate 22. Further, when entering the dielectric plate 22 from the coaxial waveguide 20, the microwave propagation medium changes from air to a dielectric, so that the wavelength of the microwave is compressed. The thickness of the dielectric plate 22 is determined so that the microwave propagates in the TE mode, that is, the electric field can be generated only in the thickness direction. There is no problem if the thickness of the dielectric plate 22 is 1/4 or less of the wavelength of the microwave in the dielectric plate 22. However, if it is too thin, there is a problem of strength, and if it is too thick, it becomes difficult to bend. Therefore, in the present embodiment, when alumina is used as the material of the dielectric plate 22, the optimum thickness is about 3 to 6 mm.

FIG. 4 shows a detailed view of the dielectric plate 22 on which the conductive film 23 is formed. A conductive film made of a metal layer is plated on the upper surface, the lower surface, and the outer peripheral surface of the dielectric plate 22. A hole 22a through which a slot center contact flange 27 (see FIG. 9) connected to the inner conductor 19a of the coaxial waveguide 19 passes is formed at the center of the dielectric plate 22. Around the hole 22a (a part of the upper surface and the lower surface of the dielectric plate 22 and the inner peripheral surface), a non-film formation area 22b where the conductive film 23 is not formed is formed. As will be described in detail later, the conductive film 23 on the lower surface of the dielectric plate 22 is electrically connected to the inner conductor 19a via the slot center contact flange 27, and the conductive film 23 on the upper surface of the dielectric plate 22 is electrically contacted. It is electrically connected to the outer conductor 19 b of the coaxial waveguide 19 through the elastic body 28 (see FIG. 9) and the cooling plate 24.

In the conductive film 23 (slot plate) on the lower surface side of the dielectric plate 22, a number of slots 23 a that transmit microwaves are formed. A pair of adjacent slots 23a are arranged in a T shape so as to be orthogonal to each other. A large number of slots 23 a are concentrically arranged on the disk-shaped conductive film 23. The length and arrangement of the slots 23 a are appropriately determined according to the wavelength of the microwave compressed by the dielectric plate 22 so that an electric field is uniformly emitted from the slots 23 a to the processing container 11. The shape of the slot 23a may be an arc shape in addition to the linear shape, and the arrangement of the slots 23a may be a spiral shape or a radial shape in addition to a concentric shape.

As shown in FIG. 5, the convex portion 22 c of the dielectric plate 22 protrudes into the slot 23 a of the conductive film 23 on the lower surface side of the dielectric plate 22. The surface (lower surface) of the convex portion 22 c is formed in a plane and protrudes outward from the surface of the conductive film 23. For this reason, as shown in FIG. 6A, the protrusion 22 c comes into contact with the dielectric window 12, and the conductive film 23 does not come into contact with the dielectric window 12. FIG. 6B shows a conventional dielectric plate 22 in which the convex portion 22 c does not protrude from the conductive film 23. In the conventional dielectric plate 22, the conductive film 23 contacts the dielectric window 12 instead of the dielectric plate 22. If this happens, the conductive film 23 may rub against the dielectric window 12 due to thermal expansion / contraction of the dielectric window 12 and the conductive film 23, and the conductive film 23 may be peeled off from the dielectric plate 22. As in the present embodiment, this problem can be solved by bringing the convex portion 22 c of the dielectric plate 22 into contact with the dielectric window 12 so that the conductive film 23 does not come into contact with the dielectric window 12. A buffer sheet 53 such as a Teflon (registered trademark) sheet or carbon sheet may be interposed in the gap between the conductive film 23 and the dielectric window 12 shown in FIG. 6A (see FIG. 14).

FIG. 7A shows a method for manufacturing the dielectric plate 22 on which the conductive film 23 is formed. FIG. 7B shows a comparative method for manufacturing the conventional dielectric plate 22. In the conventional method of manufacturing the dielectric plate 22, after the dielectric plate 22 is manufactured (S1), a non-film formation area corresponding to the slot 23a is masked (S2), and then a metal layer is formed on the dielectric plate 22. After plating (S3), the masking was removed (S4). Alternatively, after the dielectric plate 22 is manufactured (ST1), a metal layer is plated on the dielectric plate 22 (ST2), and then a portion corresponding to the slot 23a is etched (ST3). In any case, the portion corresponding to the slot 23a is a space.

On the other hand, in the manufacturing method of the present embodiment, as shown in FIG. 7A, after the dielectric plate 22 is manufactured (SP1), the convex portion 22c can be formed in the portion corresponding to the slot 23a. Then, the remaining portion of the dielectric plate 22 (the non-slot opening on the slot forming surface) is etched leaving the portion corresponding to the slot 23a (SP2). The protrusion amount of the protrusion 22c is adjusted to about 10 to 30 μm, for example. The etching method is not particularly limited, and for example, sandblasting, cutting using an end mill, chemical etching using a chemical, or the like can be employed. When blasting, the portion corresponding to the slot 23a is masked.

Thereafter, a metal layer is plated on a portion of the dielectric plate 22 other than the convex portions 22c (non-slot opening on the slot forming surface of the dielectric plate 22) (SP3). For example, the metal plate is plated on the dielectric plate 22 by immersing the whole in a plating bath in a state where the convex portions 22c of the dielectric plate 22 are masked. The thickness of the conductive film 23 is adjusted to, for example, about 5 μm to 10 μm so that the surface of the convex portion 22 c protrudes outward from the surface of the conductive film 23. Alternatively, the entire surface of the dielectric plate 22 may be put on the plating bath without masking the convex portion 22c of the dielectric plate 22, and then the metal layer attached to the convex portion 22c of the dielectric plate 22 may be scraped off.

According to this embodiment, the slot 23a is filled with a dielectric. A simulation is performed under these conditions, and the optimal shape and arrangement of the slots 23a are designed. Since the medium through which the microwave propagates does not change from the dielectric to the air, reflection of the microwave at the interface can be prevented.

It should be noted that when etching the dielectric plate 22, it is desirable to reduce the surface roughness as much as possible. Since the microwave propagates while reflecting the conductive film 23, a current flows on the surface of the conductive film 23. When the surface roughness of the dielectric plate 22 is increased, irregularities are formed on the surface of the conductive film 23 and the electrical resistance increases. When this happens, the microwave power is lost.

FIG. 8 shows an example of metal layer plating. When the conductive film 23 is formed on the dielectric plate 22, first, a thin layer 31 of Pd is electrolessly plated on the surface of the dielectric plate 22 in order to activate the surface of the dielectric plate 22. Next, a Cu layer 32 having a thickness of about 5 μm is plated on the Pd layer 31. When the temperature of the Cu layer 32 rises, it oxidizes and deteriorates. In order to prevent this, a 1-2 μm Au layer 34 is electrolytically plated. In order to plate the Au layer 34 on the Cu layer 32, the surface of the Cu layer 32 needs to be treated with Ni. For this reason, a 0.2 to 0.3 μm Ni layer 33 is electrolessly plated on the surface of the Cu layer 32. The microwave current propagating through the dielectric plate 22 mainly flows through the Cu layer.

Desirably, the conductive film 23 is plated on the upper surface, lower surface and outer peripheral surface of the dielectric plate 22. This is because if only one side is present, the dielectric plate 22 may be warped due to thermal expansion, and a gap may be generated between the dielectric plate 22 and the cooling plate 24. By forming the conductive film 23 on the upper surface of the dielectric plate 22, the microwave is reflected by the conductive film 23 on the upper surface of the dielectric plate 22. Since microwaves do not propagate outside the conductive film 23, a Teflon (registered trademark) sheet, carbon sheet, or the like having good thermal conductivity is provided between the conductive film 23 on the upper surface of the dielectric plate 22 and the cooling plate 24. A buffer sheet 36 (see FIG. 3) may be interposed. However, of course, the conductive film 23 may be formed only on the lower surface of the dielectric plate 22. In this case, it is necessary to ensure electrical connection between the conductive film 23 on the lower surface of the dielectric plate 22 and the coaxial waveguide 19.

As shown in FIG. 3, a cooling plate 24 is placed on the dielectric plate 22 of the microwave antenna 18. A cooling water flow path 24 a is formed in the cooling plate 24. The dielectric plate 22 can be cooled by flowing cooling water through the cooling water passage 24a. In order to improve thermal conductivity, one or a plurality of buffer sheets 36 having a thickness of, for example, about 0.05 mm are interposed between the cooling plate 24 and the dielectric plate 22. The buffer sheet 36 prevents the conductive film 23 on the upper surface of the dielectric plate 22 and the cooling plate 24 from rubbing due to thermal expansion. Since the amount of thermal expansion is small on the inner peripheral side of the conductive film 23 on the upper surface of the dielectric plate 22, there is little friction with the cooling plate 24. For this reason, electrical connection is made between the inner peripheral side of the conductive film 23 and the cooling plate 24.

The microwave antenna 18 is fixed to the dielectric window 12 by an antenna holder 37 attached to the dielectric window holder ring 14. The antenna holder 37 is made of Al or stainless steel containing Al, like the processing container 11. An electromagnetic shielding elastic body 38 is provided between the cooling plate 24 and the antenna holder 37. The electromagnetic shielding elastic body 38 has a function of electromagnetic shielding and a function of pressing the microwave antenna 18 against the dielectric window 12. All of the microwaves transmitted through the slot 23 a of the conductive film 23 are not absorbed by the plasma, and part of the microwave leaks out from a small gap between the conductive film 23 and the dielectric window 12. In addition, the microwave propagated in the outer circumferential direction through the dielectric window 12 leaks outside through the gap between the dielectric window pressing ring 14 and the cooling plate 24. The electromagnetic shielding elastic body 38 shields the leaked microwave. If the microwave antenna 18 is merely placed on the dielectric window 12, a gap is generated between the microwave antenna 18 and the dielectric window 12 due to thermal expansion. In order to prevent thermal expansion from generating a gap, the electromagnetic shielding elastic body 38 presses the microwave antenna 18 against the dielectric window 12 with a strong force. The two functions of the electromagnetic shielding elastic body may be divided. That is, the function of electromagnetic shield may be provided to the spiral electromagnetic shield, and the function of pressing the microwave antenna 18 against the dielectric window 12 may be provided to the spring-like O-ring that can apply tension.

FIG. 9 shows an example of an electrical connection method of the conductive film 23 of the dielectric plate 22. Since it is necessary to electrically connect the conductive film 23 on the lower surface of the dielectric plate 22 and the inner conductor 19 a of the coaxial waveguide 19, the cylindrical slot center contact flange 27 and the plate-shaped slot center contact plate 41. Is provided. As shown in FIG. 10, the slot center contact flange 27 and the slot center contact plate 41 are coupled by bonding, screws, or the like. The slot center contact flange 27 is coupled to the inner conductor 19a by screws or the like. The contact reinforcing elastic body 42 made of an O-ring or the like reinforces the electrical contact between the slot center contact plate 41 and the conductive film 23, and the electrical connection between the conductive film 23 on the upper surface side of the dielectric plate 22 and the cooling plate 24. The contact is reinforced with an electrical contact elastic 28 made of a conductive spring.

As shown in FIG. 11, the slot outer peripheral contact ring 44 and the slot outer peripheral contact plate 45 are coupled. The slot outer peripheral contact ring 44 is coupled to the cooling plate 24 with bolts or the like. A contact reinforcing elastic body 46 made of an O-ring or the like reinforces electrical contact between the slot outer peripheral contact plate 45 and the conductive film 23 on the lower surface side of the dielectric plate 22. Further, the heat transfer contact between the conductive film 23 on the upper surface of the dielectric plate 22 and the cooling plate 24 is reinforced through the heat transfer buffer sheet 36.

Note that the present invention is not limited to the above-described embodiment, and can be variously modified without departing from the gist of the present invention. For example, as shown in FIG. 12, the antenna of the present invention does not have a structure that spreads the microwave from the center to the outside like a coaxial waveguide. The structure which introduces a wave may be sufficient.

Further, the slot plate may not be a conductive film plated on the dielectric plate, but may be a copper plate separate from the dielectric plate. In this case, the convex portion of the dielectric plate may be fitted into the slot of the slot plate. Furthermore, the convex portion of the dielectric plate may be separated from the dielectric main body, and the convex portion may be attached to the dielectric main body. Further, as shown in FIG. 13, a buffer sheet 52 may be interposed between the convex portion 22 c of the dielectric plate 22 and the dielectric window 12.

Even if there is no electromagnetic shielding elastic body that presses the cooling plate and dielectric plate against the dielectric window for holding the antenna, the periphery of the cooling plate and dielectric plate is evacuated so that they are in close contact with the dielectric window. Also good.

A plasma gas supply path for supplying plasma gas into the processing container may be formed in the dielectric window, and an intermediate shower head for supplying the processing gas may be provided between the dielectric window and the substrate to be processed.

This specification is based on Japanese Patent Application No. 2009-018970 filed on Jan. 30, 2009. All this content is included here.

DESCRIPTION OF SYMBOLS 11 ... Processing container 12 ... Dielectric window 15 ... Gas supply part 16 ... Holding stand 18 ... Microwave antenna 19 ... Coaxial waveguide 20 ... Coaxial waveguide 22 ... Dielectric board 22c ... Convex part 23 ... Conductive film (slot board) )
23a ... Slot 36 ... Buffer sheet

Claims

A processing container having a ceiling defined by a dielectric window, a gas exhaust system for depressurizing the processing container, a gas supply unit for supplying plasma gas to the processing container, and the dielectric window of the processing container. In a microwave plasma processing apparatus comprising: a microwave antenna that excites plasma gas in the processing container;
The microwave antenna includes a dielectric plate that propagates the microwave in the horizontal direction and compresses the wavelength of the microwave, and a slot plate having a slot that transmits the microwave,
Protrusions projecting into the slots of the slot plate are provided on the dielectric plate,
The microwave plasma processing apparatus, wherein a surface of the convex portion of the dielectric plate protrudes outward from the surface of the slot plate toward the dielectric window.
2. The microwave plasma processing apparatus according to claim 1, wherein the slot plate is made of a conductive film formed on the dielectric plate.
The convex portion of the dielectric plate is formed by removing a remaining portion of the dielectric plate, leaving a portion corresponding to the slot,
The microwave plasma processing apparatus according to claim 2, wherein the conductive film is formed by depositing a portion other than the convex portion of the dielectric plate.
The microwave plasma processing apparatus according to claim 2 or 3, wherein the conductive film is formed on the dielectric plate by plating.
5. The microwave plasma processing apparatus according to claim 1, wherein a gap is provided between the slot plate and the dielectric window.
The microwave plasma processing apparatus according to any one of claims 1 to 4, wherein a buffer sheet is interposed between the slot plate and the dielectric window.
The microwave plasma processing apparatus further includes a cooling plate that cools the microwave antenna and sandwiches the dielectric plate with the dielectric window in a vertical direction,
A conductive film that reflects microwaves is formed on the top surface of the dielectric plate,
The microwave plasma processing apparatus according to claim 2, wherein a buffer sheet is interposed between the conductive film on the upper surface of the dielectric plate and the cooling plate.
A dielectric plate with a slot plate for a microwave plasma processing apparatus for plasma processing a target object by plasma generated using microwaves,
A slot plate having slots for transmitting microwaves;
A dielectric with a slot plate for a microwave plasma processing apparatus, comprising: a dielectric plate having a convex portion protruding into the slot of the slot plate, and a surface of the convex portion protruding outward from the surface of the slot plate. Body board.
9. The dielectric plate with a slot plate for a microwave plasma processing apparatus according to claim 8, wherein the slot plate is made of a conductive film formed on the dielectric plate.
A method of manufacturing a dielectric plate with a slot plate for a microwave plasma processing apparatus for plasma processing a target object with plasma generated using a microwave,
Removing the remaining portion of the dielectric plate leaving the portion corresponding to the slot so that the portion corresponding to the slot through which microwaves of the slot plate are transmitted becomes a convex portion;
Forming a slot plate made of a conductive film on a portion of the dielectric plate other than the convex portion so that the surface of the convex portion protrudes outward from the surface of the slot plate. A method of manufacturing a dielectric plate with a slot plate for an apparatus.