TWI837749B - Plasma treatment device - Google Patents

Abstract

The subject of the present invention is to reduce the possibility of particles moving in a vacuum container adhering to a dielectric cover. A magnetic field introduction window (3) arranged on the wall of a vacuum container (2) comprises: a metal plate (31) formed with a plurality of slits (311); a dielectric cover (32) covering the plurality of slits (311); a gasket (33) arranged between the dielectric cover (32) and the metal plate (31); and an anti-adhesion plate (34) arranged on the metal plate (31) in a manner covering at least a portion of the plurality of slits (311).

Description

Plasma treatment equipment

The present invention relates to a plasma processing device for processing an object using plasma.

There is known a plasma processing device that generates plasma by flowing a high-frequency current through an antenna and uses the plasma to process a substrate or other object to be processed. For example, the plasma processing device described in Patent Document 1 includes: a vacuum container having an opening; a metal plate that is provided to block the opening and has a plurality of slits extending in the thickness direction; a plate-shaped dielectric cover that is supported by contact with the metal plate and blocks the plurality of slits from the outside of the vacuum container; and an antenna that is provided outside the vacuum container in a manner facing the metal plate. A high-frequency electric field and a high-frequency magnetic field are generated by flowing a high-frequency current through the antenna, and the high-frequency magnetic field is transmitted into the vacuum container through the dielectric cover and the slits of the metal plate. In this way, inductively coupled plasma can be generated in the vacuum container. [Prior art literature] [Patent literature]

[Patent Document 1] Japanese Patent Publication No. 2020-198282

[The problem that the invention wants to solve]

When various treatments are performed using the plasma processing device of the structure, particles in the vacuum container sometimes move and adhere to and accumulate on the inner side of the vacuum container, the metal plate, and the dielectric cover. For example, when the plasma processing device is used as a sputtering device, the sputtering particles adhere to and accumulate on the dielectric cover. When the accumulation of the sputtering particles is a conductive metal film, the metal film accumulated on the dielectric cover may be connected to the metal plate at the slit. At this time, if a high-frequency current flows through the antenna, the metal film and the metal plate are inductively heated, and the dielectric cover is heated. Since the dielectric cover is responsible for maintaining the vacuum in the vacuum container, it is not desirable to heat the dielectric cover. Therefore, the dielectric cover needs to be cleaned frequently.

One form of the present invention aims to realize a plasma processing device that can reduce the possibility of sputtering particles, such as particles moving in a vacuum container, adhering to a dielectric cover. [Means for solving the problem]

To solve the above problem, a plasma processing device of one form of the present invention includes: a vacuum container, which contains a processed object; an antenna, which is arranged outside the vacuum container and generates a high-frequency magnetic field; and a magnetic field introduction window, which is arranged on the wall of the vacuum container and introduces the high-frequency magnetic field into the interior of the vacuum container in order to generate plasma inside the vacuum container, and the magnetic field introduction window includes: a metal plate, which is formed with a plurality of slits; a dielectric cover, which covers the plurality of slits; a gasket, which is arranged between the dielectric cover and the metal plate; and an anti-adhesion plate, which is arranged on the metal plate in a manner that covers at least a portion of the plurality of slits. [Effect of the invention]

According to one aspect of the present invention, the possibility of particles moving in a vacuum container being attached to a dielectric cover can be reduced.

Hereinafter, the embodiments of the present invention will be described in detail. In order to facilitate the description, the same symbols are attached to the components having the same functions as the components shown in each embodiment, and the description thereof will be appropriately omitted.

[Implementation method 1] An implementation method of the present invention is described with reference to Figures 1 to 4.

<Structure of plasma processing device 1> FIG. 1 is a cross-sectional view showing the schematic structure of the plasma processing device 1 of the present embodiment. In FIG. 1 , the direction in which the antenna 7 extends is set as the X-axis direction, the direction from the vacuum container 2 toward the antenna 7 is set as the Z-axis direction, and the direction orthogonal to the X-axis direction and the Z-axis direction is set as the Y-axis direction.

As shown in FIG1 , a plasma processing device 1 is a device for performing plasma processing on a substrate or other object to be processed W1 using an inductively coupled plasma P1. Here, the substrate is, for example, a substrate for a flat panel display (FPD) such as a liquid crystal display or an organic electroluminescence (EL) display, or a flexible substrate for a flexible display. In addition, the object to be processed W1 may be a semiconductor substrate for various purposes. Furthermore, the object to be processed W1 is not limited to a substrate-like form, such as a tool. The processing performed on the object to be processed W1 is, for example, film formation using a plasma chemical vapor deposition (CVD) method or a sputtering method, etching using plasma, ashing, and removal of a coating film.

The plasma processing device 1 includes a vacuum container 2, a magnetic field introduction window 3, an antenna 7, and a holding portion 9. A processing chamber 21 is formed inside the vacuum container 2, which is evacuated and into which a gas is introduced. The vacuum container 2 is, for example, a metal container. An opening 23 is formed on a wall surface 22 (the upper surface in the example of FIG. 1 ) of the vacuum container 2 and is passed through in the thickness direction. The vacuum container 2 is electrically grounded.

The gas introduced into the processing chamber 21 only needs to correspond to the processing content of the processing object W1 accommodated in the processing chamber 21. For example, when a film is formed on the processing object W1 by plasma CVD (Chemical Vapor Deposition) method, the gas is a raw material gas or a gas diluted with a diluent gas such as _H2 . To give further specific examples, when the raw material gas is _SiH4 , a Si film can be formed on the object W1 to be processed; when the raw material gas is _SiH4 + _NH3 , a SiN film can be formed on the object W1 to be processed; when the raw material gas is _SiH4 + _O2 , a _SiO2 film can be formed on the object W1 to be processed; when the raw material gas is _SiF4 + _N2 , a SiN:F film (silicon fluoride nitride film) can be formed on the object W1.

<Structure of magnetic field introduction window 3> Fig. 2 is a top view showing the schematic structure of the magnetic field introduction window 3. Fig. 3 is a cross-sectional view taken along line A-A of Fig. 2, and Fig. 4 is a cross-sectional view taken along line B-B of Fig. 2. In addition, in Figs. 2 to 4, antenna 7 is omitted. Furthermore, in Fig. 2, dielectric cover 32 described later is omitted. The omitted components are indicated by a dotted chain.

The magnetic field introduction window 3 includes a metal plate 31 and a dielectric cover 32. The magnetic field introduction window 3 introduces the high-frequency magnetic field generated by the antenna 7 into the processing chamber 21 in order to generate plasma in the processing chamber 21. The metal plate 31 and the dielectric cover 32 are sequentially arranged toward the Z-axis direction.

The metal plate 31 is disposed on the wall surface 22 of the vacuum container 2 so as to block the opening 23. A plurality of slits 311 penetrating the metal plate 31 in the Z-axis direction are formed in the metal plate 31. The plurality of slits 311 extend in the Y-axis direction and are arranged in the X-axis direction. The metal plate 31 is arranged substantially parallel to the surface of the object W1.

The dielectric cover 32 is provided from the outer side of the vacuum container 2 in a manner covering the plurality of slits 311. The dielectric cover 32 is entirely made of a dielectric material and is in a flat plate shape. The material constituting the dielectric cover 32 may be a ceramic such as alumina, silicon carbide or silicon nitride, an inorganic material such as quartz glass or alkali-free glass, or a resin material such as a fluororesin such as Teflon (registered trademark).

In this embodiment, the magnetic field introduction window 3 further includes a gasket 33 and an anti-adhesion plate 34. The gasket 33 is disposed between the metal plate 31 and the dielectric cover 32. The gasket 33 may also be an O-ring, and examples of the material of the gasket 33 include fluorinated rubber (viton) and the like. The vacuum in the processing chamber 21 is maintained by the metal plate 31 blocking the opening 23, the dielectric cover 32 covering the plurality of slits 311, and the gasket 33.

The anti-adhesion plate 34 is disposed on the metal plate 31 so as to cover at least a portion of the plurality of slits 311. The anti-adhesion plate 34 may be made of the same material as the dielectric cover 32, or may be thinner than the dielectric cover 32.

According to the above structure, the metal plate 31 and the dielectric cover 32 are separated by the gasket 33. Thus, even if induction heating occurs in the metal plate 31, the amount of heat transferred from the metal plate 31 to the dielectric cover 32 can be reduced. In addition, even if particles moving in the vacuum container 2 pass through the plurality of slits 311 in the metal plate 31, since a part of the particles adhere to the anti-adhesion plate 34, the possibility of adhering to the dielectric cover 32 can be reduced. As a result, the possibility of the dielectric cover 32 being heated due to the particles adhering to and accumulating on the dielectric cover 32 can be reduced.

Furthermore, as shown in Fig. 1 and Fig. 2, it is desirable to provide a plurality of anti-adhesion plates 34 covering a plurality of slits 311 on the metal plate 31, and to provide gaskets 33 around the plurality of anti-adhesion plates 34. In this case, since gaskets 33 are also provided between adjacent anti-adhesion plates 34, the distance between the metal plate 31 and the dielectric cover 32 can be maintained more reliably.

In addition, as shown in FIG. 1 and FIG. 2 , it is desirable that each of the plurality of anti-adhesion plates 34 does not block the slits 311. That is, a portion of the slits 311 is exposed from the anti-adhesion plates 34. Thereby, the space formed by the metal plate 31, the dielectric cover 32 and the gasket 33 is connected to the internal space of the vacuum container 2, so that the gas in the space can be sucked through the internal space by a vacuum pump (not shown). As a result, it is possible to prevent the pressure difference from being generated between the space and the internal space.

The high-frequency magnetic field generated from the antenna 7 is supplied to the processing chamber 21 through the dielectric cover 32, the anti-adhesion plate 34, and the plurality of slits 311. Thus, the inductively coupled plasma P1 is generated in the processing chamber 21.

(Additional Notes) If the vacuum container 2 is evacuated, pressure toward the metal plate 31 is applied to the dielectric cover 32 due to the pressure difference between the inside and outside of the vacuum container 2. As a result, the gasket 33 is compressed and the dielectric cover 32 moves toward the metal plate 31. In addition, the portion of the dielectric cover 32 not supported by the gasket 33 bends toward the metal plate 31.

At this time, if the dielectric cover 32 and the anti-adhesion plate 34 come into contact, pressure is applied from the dielectric cover 32 to the anti-adhesion plate 34. Therefore, the anti-adhesion plate 34 not only reduces the possibility of particles moving in the vacuum container 2 being attached to the dielectric cover 32, but also maintains the pressure difference between the inside and the outside of the vacuum container 2. However, in this case, it is considered that the anti-adhesion plate 34 may be damaged by the pressure applied from the dielectric cover 32 to the anti-adhesion plate 34.

Therefore, it is desirable that the dielectric cover 32 has a predetermined strength so that the dielectric cover 32 and the anti-adhesion plate 34 do not contact each other even when the vacuum container 2 is evacuated. In addition, the gasket 33 is preferably configured to support the dielectric cover 32 around the anti-adhesion plate 34 as shown in FIG. 2 . In this case, the structure for reducing the possibility of the particles adhering to the dielectric cover 32 and the structure for maintaining the pressure difference between the inside and the outside of the vacuum container 2 are separated into the anti-adhesion plate 34 and the dielectric cover 32, respectively.

[Implementation Method 2] Another implementation method of the present invention is described with reference to Figures 5 and 6.

Fig. 5 is a cross-sectional view showing a schematic structure of the plasma processing apparatus 1 of the present embodiment. Fig. 6 is a cross-sectional view taken along line C-C of Fig. 5. The plasma processing apparatus 1 of the present embodiment is different from the plasma processing apparatus 1 shown in Figs. 1 to 4 in the shape of the metal plate 31, but the other structures are the same.

As shown in FIG. 5 and FIG. 6 , the metal plate 31 of the present embodiment is different from the metal plate 31 shown in FIG. 1 to FIG. 4 in that the area facing the anti-adhesion plate 34 and between the slits 311 is a recess 312 , and the other structures are the same.

According to the above structure, the anti-adhesion plate 34 is separated from the metal plate 31 at the portion facing the recess 312. Therefore, even if particles are attached to the anti-adhesion plate 34 at the portion facing the slit 311 to form a conductive film, it is difficult for the conductive film to contact the recess 312 and conduct. In this way, when a high-frequency current flows through the antenna 7, it is possible to prevent an induced current from being generated in the metal plate 31. As a result, it is possible to prevent the intensity of the magnetic field generated by the antenna 7 from being reduced due to the induced current.

Furthermore, if the film forming speed of the sputtering device used in the mass production line is about 200 nm/min, the depth of the recess 312 is preferably more than 2 mm. In this case, it takes more than 150 hours before the conductive film and the recess 312 are connected. Therefore, even if the sputtering device is operated continuously, the maintenance of the magnetic field introduction window 3 only needs to be about once a week. Furthermore, the upper limit of the depth of the recess 312 is determined by various conditions such as the thickness and strength of the metal plate 31.

(Notes) Furthermore, in the above-described embodiment, the anti-adhesion plate 34 is disposed on the upper surface of the metal plate 31, but it may also be disposed on the lower surface of the metal plate 31. However, in this case, it is necessary to fix the anti-adhesion plate 34 to the metal plate 31 using a bonding material or the like. In addition, in the above-described embodiment, the dielectric cover 32 is in the form of a plate, but it is not limited thereto, and may also be in the form of a box with one side open.

[Conclusion] The plasma processing device of form 1 of the present invention has the following structure, namely, it includes: a vacuum container, which accommodates the processed object inside; an antenna, which is arranged outside the vacuum container and generates a high-frequency magnetic field; and a magnetic field introduction window, which is arranged on the wall of the vacuum container and introduces the high-frequency magnetic field into the interior of the vacuum container in order to generate plasma inside the vacuum container, and the magnetic field introduction window includes: a metal plate, which is formed with a plurality of slits; a dielectric cover, which covers the plurality of slits; a gasket, which is arranged between the dielectric cover and the metal plate; and an anti-adhesion plate, which is arranged on the metal plate in a manner covering at least a part of the plurality of slits.

According to the structure, the dielectric cover is separated from the metal plate by the gasket. In addition, the anti-adhesion plate covers at least a part of the plurality of slits in the metal plate. Thereby, if particles moving in the vacuum container want to pass through the plurality of slits in the metal plate, they are attached to the anti-adhesion plate, thereby reducing the possibility of being attached to the dielectric cover. As a result, the possibility of the dielectric cover being heated due to the particles being attached and accumulated on the dielectric cover can be reduced.

The plasma processing device of the second aspect of the present invention is as described in the first aspect, wherein the magnetic field introduction window includes a plurality of anti-adhesion plates covering a plurality of the plurality of slits, and the gasket is disposed around each of the plurality of anti-adhesion plates. In this case, since the gasket is also disposed between adjacent anti-adhesion plates, the distance between the metal plate and the dielectric cover can be more reliably maintained.

The plasma processing device of the third aspect of the present invention is as described in the first aspect and the second aspect, wherein preferably, the space between the dielectric cover and the anti-adhesion plate is connected to the inner space of the vacuum container. In this case, the gas in the space can be sucked through the inner space of the vacuum container by a vacuum pump. As a result, a pressure difference can be prevented from being generated between the space and the inside of the vacuum container.

The plasma processing apparatus of form 4 of the present invention is as described in forms 1 to 3, wherein the portion between the adjacent slits of the metal plate facing the anti-adhesion plate may be a recessed portion.

In this case, the anti-adhesion plate is separated from the metal plate at the portion facing the concave portion. Therefore, even if particles are attached to the anti-adhesion plate at the portion facing the slit to form a conductive film, the conductive film is unlikely to contact the concave portion and conduct. This prevents the metal plate from generating an induced current when a high-frequency current flows through the antenna. As a result, the intensity of the magnetic field generated by the antenna can be prevented from being reduced due to the induced current.

The plasma processing device of the fifth aspect of the present invention is as described in the fourth aspect, wherein preferably, the depth of the recess is 2 mm or more. In this case, even if the plasma processing device is operated continuously, the maintenance of the magnetic field introduction window only needs to be performed once a week.

The present invention is not limited to the various embodiments described above, and various modifications can be made within the scope indicated in the claims. Embodiments obtained by appropriately combining the technical means respectively disclosed in different embodiments are also included in the technical scope of the present invention.

1: Plasma treatment device 2: Vacuum container 3: Magnetic field introduction window 7: Antenna 9: Holding part 21: Treatment chamber 22: Wall surface 23: Opening part 31: Metal plate 32: Dielectric cover 33: Gasket 34: Anti-adhesion plate 311: Slit 312: Recess A-A: Line B-B: Line C-C: Line P1: Inductively coupled plasma (plasma) W1: Object to be treated

FIG. 1 is a cross-sectional view showing a schematic structure of a plasma processing device according to an embodiment of the present invention. FIG. 2 is a top view showing a schematic structure of a magnetic field introduction window in the plasma processing device. FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2. FIG. 5 is a cross-sectional view showing a schematic structure of a plasma processing device according to another embodiment of the present invention. FIG. 6 is a cross-sectional view taken along line C-C of FIG. 5.

1: Plasma treatment device

2: Vacuum container

3: Magnetic field introduction window

7: Antenna

9: Maintaining part

21: Processing room

22: Wall

23: Opening

31:Metal plate

32: Dielectric cover

33: Gasket

34: Anti-adhesion plate

311: Narrow seam

P1: Inductively coupled plasma (plasma)

W1: Object to be processed

Claims (5)

A plasma processing device includes: a vacuum container, which contains a processed object; an antenna, which is arranged outside the vacuum container and generates a high-frequency magnetic field; and a magnetic field introduction window, which is arranged on the wall of the vacuum container and introduces the high-frequency magnetic field into the interior of the vacuum container in order to generate plasma inside the vacuum container, wherein the magnetic field introduction window includes: a metal plate, which is formed with a plurality of slits; a dielectric cover, which covers the plurality of slits; a gasket, which is arranged between the dielectric cover and the metal plate; and an anti-adhesion plate, which is arranged on the metal plate in a manner of covering at least a portion of the plurality of slits. The plasma processing device as described in claim 1, wherein the magnetic field introduction window includes a plurality of anti-adhesion plates covering a plurality of the plurality of slits, and the gasket is disposed around each of the plurality of anti-adhesion plates. A plasma processing device as described in claim 1 or claim 2, wherein the space between the dielectric cover and the anti-adhesion plate is connected to the internal space of the vacuum container. A plasma processing device as described in claim 1 or claim 2, wherein the portion of the metal plate between the adjacent slits facing the anti-adhesion plate is a recess. A plasma processing device as described in claim 4, wherein the depth of the recess is greater than 2 mm.

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