Plasma processing equipment

Abstract

The present invention provides means and methods for preventing leakage of high-frequency currents, etc., due to the overlap of Vdc and high-frequency voltage through support members, piping, etc. (connecting members), etc., that connect the inside and outside of the reaction chamber of a plasma processing apparatus. [Solution] A connection mechanism characterized by comprising: an intervening member 25 made of insulating material interposed between a first flange 23 and a second flange 24 provided at the opposing ends of two pipes 21 and 22; a first cavity 28 and a second cavity 29 provided inward from the side wall of the intervening member 25; a screw (bolt and nut) 26 fastening the first flange 23 and the first cavity 28; a screw 27 fastening the second flange 24 and the second cavity 29; and sealing members 30 and 31, both made of insulating material, that seal at least the surface side of the first cavity 28 and the second cavity 29.

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus used for performing various plasma processes such as etching, film formation, and cleaning on a workpiece such as a semiconductor wafer.

Background Art

[0002] In a plasma processing apparatus, a workpiece is placed in a sealed reaction chamber, and after introducing a source gas that becomes a raw material for plasma into the reaction chamber, high-frequency power is applied to convert the source gas into plasma. By appropriately setting the conditions during the plasma conversion, various plasma processes such as etching, film formation, and cleaning can be performed on the workpiece.

[0003] General plasma generation apparatuses include an inductively coupled plasma (ICP) generation apparatus that uses a high-frequency induction coil and a capacitively coupled plasma (CCP) generation apparatus that uses an electrode plate pair. In any case, since power for converting the source gas into plasma is input into the reaction chamber, the temperature in the reaction chamber rises. Along with this, the temperature of the workpiece also rises. However, when the workpiece cannot withstand this, a cooling mechanism is incorporated in the mounting table on which the workpiece in the reaction chamber is placed in order to cool the workpiece. The cooling mechanism often has a structure in which an insulating fluid such as a fluorine-based inert liquid, water, or a refrigerant such as liquid nitrogen is flowed through a flow path formed inside the mounting table. In that case, the refrigerant is supplied to the mounting table from the outside of the reaction chamber through the inside of a hollow columnar support member that supports the mounting table. In addition, the reaction chamber also requires pipes for introducing the source gas into the reaction chamber and pipes for discharging the processed gas.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described above, support members and various pipes connect the inside and outside of the reaction chamber of the plasma processing apparatus. For example, if such pipes are connected to the live part of the reaction chamber, the self-bias (hereinafter referred to as Vdc) generated in the substrate mounting section inside the reaction chamber when plasma is generated can reach several kV to tens of kV. The high-frequency current generated from this self-bias leaks through the pipes, causing adverse effects on external electronic equipment.

[0006] Conventionally, flanges were provided at the opposing ends of the metal pipes on both sides, a sheet-like or plate-like insulating material was interposed between the two flanges, and the two flanges were tightened and fixed with screws. In addition, insulating washers were interposed between each screw and flange to prevent leakage of high-frequency current through the two metal pipes.

[0007] Furthermore, Patent Document 1 discloses a configuration in which, as schematically shown in Figures 1(a) and (b), when fixing the interposed plate-shaped insulator 11 and the flanges 12 and 13 on both sides, the bolts are used to fix one flange 12 to the plate-shaped insulator 11 and the plate-shaped insulator 11 to the other flange 13 alternately, so that the bolts do not penetrate both flanges 12 and 13.

[0008] However, in the configuration of Patent Document 1, one end A of bolts 14 and 15 is electrically connected to or close to flanges 12 and 13, and at the other end B, if there is a blocking capacitor in the high-frequency circuit and Vdc is generated, or if the current is high frequency, depending on the surface condition of the insulator such as the adhesion of trace amounts of components in the air, when the voltage difference exceeds a threshold, a large DC current leakage (surface discharge) occurs suddenly through the surface of the insulator between flanges 12 and 13 and the heads (or nuts) of bolts 14 and 15 due to the voltage such as Vdc at the electrode part or high frequency, and in some cases the sealing member such as plate-shaped insulator or O-ring may be damaged due to heat generation, causing leakage of internal fluid.

[0009] The present invention provides means and methods for preventing short circuits through support members, piping, etc. (hereinafter referred to as "connecting members") that connect the inside and outside of a reaction chamber when the voltage such as Vdc or high frequency rises too high in a plasma processing apparatus, and for preventing leakage of high frequency current. [Means for solving the problem]

[0010] The connection mechanism in the connecting member of a plasma processing apparatus according to the present invention, which was developed to solve the above problems, A first flange and a second flange are provided at the opposing ends of two connecting members, An intervening member made of insulating material is interposed between the first flange and the second flange, The first cavity and the second cavity are provided inward from the side wall of the interfacing member, A first fastener for fastening the first flange and the first cavity, A second fastener for fastening the second flange and the second cavity It is characterized by being equipped with [the following features].

[0011] In the above-described connection mechanism, the first cavity or the second cavity may be provided with a sealing member made of an insulating material that seals at least its surface. Of course, sealing members may also be provided in both the first cavity and the second cavity.

[0012] To seal fluids or gases, it is preferable to provide O-rings between the first flange and the intervening member, and between the second flange and the intervening member.

[0013] In the connection mechanism of the present invention, the intervening member may be provided with a third cavity, a fourth cavity, etc., in addition to the first cavity and the second cavity, and these may be fastened to the first flange and the second flange. However, it is desirable that the number of cavities be even, and that the same number of cavities be fastened to the first flange and the second flange. Furthermore, it is desirable that the fastenings to the first flange and the second flange be axially symmetric with respect to the central axis of the two connecting members (hereinafter simply referred to as the central axis).

[0014] The first cavity and the second cavity may be separate and isolated (i.e., a part of an intervening member separating the two cavities is interposed between them), or they may be the same cavity (i.e., a single cavity). The former structure is preferable to the latter structure because the intervening member is interposed between the cavities, making it less likely to break even if the intervening member does not have the strength of metal, and increasing the strength of both ends of the intervening member. The same applies when a third cavity, a fourth cavity, etc., are present. In those cases, the cavity may extend around the entire circumference. In any case, the cavity in the present invention is one in which a part of an intervening member is interposed between the first flange or the second flange.

[0015] The term "fastener for fastening a flange and a cavity" more precisely refers to a fastener that fastens a flange to an intermediary member between the flange and the cavity. This fastener may be a screw that is screwed into the intermediary member through a large-diameter hole (or screw hole) provided in the flange from the flange side (in this case, the tip of the screw may or may not protrude into the cavity), but in this case, it is preferable to screw it in with a torque that does not damage the plate-like insulator, which does not have the strength of metal. Conversely, it may also be a screw that is screwed into the flange through a large-diameter hole (or screw hole) provided in the intermediary member from the cavity side (in this case, the tip of the screw may or may not protrude from the other surface of the flange). Furthermore, this fastener may consist of a bolt that penetrates the flange and the intermediary member, and a nut or other female threaded member that is screwed in from the tip of the bolt.

[0016] The sealing member seals at least the surface side of the cavity after the flange and cavity have been fastened together, so that the fasteners do not come into contact with the surface of the sealing member. For example, an adhesive (however solidified) that fills the cavity can be suitably used. Alternatively, it may be a lid that seals the opening of the cavity on the outer circumference side of the interfacing member. The first sealing member and the second sealing member may be made of the same material or may be made of different materials. [Effects of the Invention]

[0017] According to the connection mechanism of the present invention, an interposed member is interposed between a first flange and a second flange provided on two connection members respectively, and the interposed member, the first flange, and the second flange are fixed (fastened) using a first fastener and a second fastener respectively by cavities provided inward from the side walls of the interposed member. Thereby, since the current path from the first flange to the second flange (or in the reverse direction) becomes a long path even when passing through the fastener, discharge between the two is effectively prevented.

[0018] Further, when each cavity, that is, the end of the fastener on the side of the interposed member is blocked by a blocking member made of an insulating material, even when Vdc and a high-frequency voltage overlap and the voltage difference becomes large, the distance of the exposed portion on the outer surface where surface discharge occurs becomes large, thereby avoiding a short circuit. Also, even if there is a leakage (surface discharge) of current (high-frequency) on the flange side, current leakage is surely prevented at the end of the fastener on the side of the interposed member. Therefore, as a whole, the situation where high-frequency current generated from Vdc inside and outside the reaction chamber leaks through connection members such as pipes connected to the support member and the active part of the plasma processing apparatus and affects external electronic devices is prevented.

Brief Description of the Drawings

[0019] [Figure 1] Vertical sectional view (a) and plan view (b) of the connection mechanism of the conventional connection member. [Figure 2] Vertical sectional view (a) during the construction process of the connection mechanism of an embodiment of the present invention, vertical sectional view (b) after the construction process is completed, and plan view (c). [Figure 3] Vertical sectional view (a) during the construction process of the connection mechanism of another embodiment of the present invention, vertical sectional view (b) after the construction process of one aspect is completed, vertical sectional views (c), (d), (e) after the construction process of another aspect is completed, and plan view (f). [Figure 4] Cross-sectional views (a) of the cavity portion during the construction process according to various aspects of the connection mechanism of the above another embodiment and cross-sectional views (b) to (e) of the same after the construction process is completed.

Modes for Carrying Out the Invention

[0020] A connection mechanism according to an embodiment of the present invention will be described with reference to FIG. 2. FIG. 2(a) is a longitudinal sectional view of the connection mechanism to which the present invention is applied for connecting two pipes 21 and 22. Disk-shaped flanges 23 and 24 are provided at the connection ends of the two pipes 21 and 22, respectively, and the two flanges 23 and 24 sandwich a disk-shaped interposing member 25 made of an insulating material (such as plastic or hard rubber) and are fixed by two screws (bolts and nuts) 26 and 27. As shown in FIG. 2(c), the two screws 26 and 27 are provided at axially symmetric positions with respect to the central axes of the two pipes 21 and 22.

[0021] Describing the connection state in detail, one flange 23 is fixed to the interposing member 25 by one screw 26, and the other flange 24 is fixed to the interposing member 25 by the other screw 27. By being fixed together to one interposing member 25 in this way, the two flanges 23 and 24 and the two pipes 21 and 22 are connected to each other.

[0022] Hollow portions 28 and 29 are provided inward from the side surfaces of the interposing member 25 at the locations where the screws 26 and 27 are provided, and each screw 26 and 27 is fastened between the outer surfaces (upper and lower in FIG. 2(a)) of the respective flanges 23 and 24 and the inner surfaces of the respective hollow portions 28 and 29, sandwiching the respective flanges 23 and 24 and the interposing member 25.

[0023] After thus fastening the respective flanges 23 and 24 and the interposing member 25 with the respective screws 26 and 27 (in the above expression, the respective flanges 23 and 24 and the respective hollow portions 28 and 29), as shown in FIG. 2(b), the respective hollow portions are filled with embedding materials (sealing members) 30 and 31 made of an insulating material. As the embedding materials 30 and 31, various adhesives or lids made of rubber, plastic, etc. can be used.

[0024] According to the connection mechanism of this embodiment, voltages such as Vdc and high-frequency currents applied to one pipe 21 and flange 23 are reliably prevented from being transmitted to the other flange 24 and pipe 22 by the intervening member 25. Furthermore, even if such a high-frequency current is applied to the screw 26, the other end of the screw 26 is completely covered by the intervening member 25 and the embedded material 30, thus preventing transmission through the surface (surface discharge).

[0025] In this embodiment, for the sake of simplicity, the two flanges 23 and 24 are fastened with two screws 26 and 27, but in reality, it is preferable to use four, six, or other screws.

[0026] A connection mechanism, which is another embodiment of the present invention, will be described with reference to Figures 3 and 4. Figure 3(a) is a longitudinal cross-sectional view of a connection mechanism to which the present invention is applied to connect two pipes 41 and 42 having different inner diameters. Disc-shaped flanges 43 and 44 are provided at the connection ends of the two pipes 41 and 42, respectively, and both flanges 43 and 44 are fixed by six screws (bolts and nuts) 461 to 466, sandwiching a cylindrical interposing member 45 made of an insulating material (plastic, hard rubber, etc.). As shown in Figure 3(f), the six screws 461 to 466 are provided in positions axially symmetric with respect to the central axis of both pipes 41 and 42, and alternately fasten one flange 43 and the other flange 44 to the interposing member 45. In the connection mechanism of this embodiment, three grooves 47 are provided around the entire circumference of the intervening member 45. In addition, one end face of the intervening member 45 (the upper end face in Figure 3(a)) is recessed in a disc shape in the direction of the central axis, and the flange 43 on that side is connected to the intervening member 45 at the bottom surface of the recessed portion 451. O-rings 48 and 49 are interposed between each flange 43, 44 and the corresponding end face of the intervening member 45.

[0027] To describe the connection in detail, as shown in Figure 3(f), one flange 43 is fixed to the interfacing member 25 by three screws 461, 463, and 465 that are spaced at equal intervals of 120° around the central axis, while the other flange 44 is fixed to the interfacing member 25 by three screws 462, 464, and 466 that are spaced between adjacent screws 461, 463, and 465. By being fixed together to a single interfacing member 45 in this way, both flanges 43 and 44 and both pipes 41 and 42 are connected to each other.

[0028] As shown in Figure 4(a), cavities 501 to 506 are provided on the sides of the interfacing member 45 where the screws 461 to 466 are installed, extending inward. Each screw 461 to 466 fastens between the outer surfaces (top and bottom in Figure 3(a)) of the flanges 43 and 44 and the inner surfaces of the cavities 501 to 506, sandwiching the flanges 43 and 44 and the interfacing member 45.

[0029] After fastening the flanges 43 and 44 to the interfacing member 45 (or, in the above expression, the flanges 43 and 44 to the cavities 501 to 506) with the screws 461 to 466, the cavities 501 to 506 (in Figure 4(b), the numbering of cavities 502 to 506 is omitted) are filled with a filling material 51 made of an insulating material, as shown in Figures 3(b) and 4(b). Various adhesives or lids made of rubber, plastic, etc. can be used as the filling material 51. The filling material may completely fill the cavities 501 and reach the surface of the interfacing member 45, as shown in Figure 3(b), or it may only fill the portion with screws 461 and seal the surface side of the cavities in a manner that does not reach the outermost surface of the interfacing member 45, as shown in Figure 3(c).

[0030] According to the connection mechanism of this embodiment, voltages such as Vdc and high frequencies applied to one pipe 41 and flange 43 are reliably prevented from being transmitted to the other flange 44 and pipe 42 by the intervening member 45. Furthermore, even if such high-frequency currents are applied to screws 461, 463, and 465, the other ends of screws 461, 463, and 465 are all covered by the intervening member 45 and the embedded material 51, thus preventing transmission through the surface (surface discharge). Moreover, in the connection mechanism of this embodiment, the intervening member 45 itself is provided with circumferential grooves 47, which further effectively prevents surface discharge and reduces leakage current.

[0031] In this embodiment of the connection mechanism, it is not necessary to fill all of the cavities 501 to 506. As shown in Figures 3(d), 3(e), and 4(c), only the portion of the interfacing member 45 on the surface side of the screws 461 to 466 may be closed with insulating covers 53 and 54. Alternatively, as shown in Figure 4(d), a cavity that groups multiple screws together may be filled with insulating embedding material 55. Furthermore, as shown in Figure 4(e), a cavity that encircles the entire circumference of the interfacing member 45 may be filled with embedding material 56.

[0032] Furthermore, any or all of the cavities 28, 29, and 501-506 may be left as cavities without the installation of any buried material (sealing member). [Explanation of Symbols]

[0033] 21, 22, 41, 42... pipes 23, 24, 43, 44… flange 25, 45... Assistive components 26, 27, 461-466... ​​Screws (bolts and nuts) 28, 29, 501~506...Cavity 30, 31, 51, 52, 53, 54, 55, 56... Buried material 47...Groove 48, 49... O-rings

Claims

1. A connection mechanism in a connecting member of a plasma processing apparatus, A first flange and a second flange are provided at the opposing ends of two connecting members, An intervening member made of insulating material is interposed between the first flange and the second flange, The first cavity and the second cavity are provided inward from the side wall of the interfacing member, A first fastener for fastening the first flange and the first cavity, A second fastener that fastens the second flange and the second cavity A connection mechanism characterized by comprising the above.

2. The connection mechanism according to claim 1, wherein a sealing member made of an insulating material is provided in the first cavity or the second cavity, sealing at least its surface side.

3. The connection mechanism according to claim 1 or 2, wherein the first fastener consists of one or more bolts and nuts, and the second fastener consists of the same number of bolts and nuts.

4. The connection mechanism according to claim 3, wherein the first fastener consists of two or more bolts and nuts, and the first cavity and the second cavity are provided separately for each of the two or more bolts and nuts.

5. The connection mechanism according to claim 2, wherein the sealing member seals only the surface of the corresponding cavity.

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