Edge ring and method of replacing same, substrate support pedestal, and plasma processing system

Abstract

The present invention provides an edge ring, a substrate support table, a plasma processing system, and a method for replacing an edge ring, which has a substrate placement surface on which a substrate is placed, a ring placement surface on which an edge ring is placed, wherein the edge ring is arranged so as to surround a substrate placed on the substrate placement surface, and an electrode for adsorbing and holding the edge ring to the ring placement surface by electrostatic force, the edge ring having a heat transfer sheet attached to a surface opposite the ring placement surface and placed on the ring placement surface via the heat transfer sheet, the heat transfer sheet having a conductive film formed on a surface opposite the ring placement surface, the edge ring being held to the ring placement surface by adsorbing the conductive film of the heat transfer sheet attached to the edge ring by electrostatic force generated by the electrode. According to the present invention, it is possible to maintain the thermal conductivity between the edge ring and the substrate support table via the heat transfer sheet while improving the peelability of the heat transfer sheet from the substrate support table.

Description

Technical Field

[0001] This invention relates to an edge ring, a substrate support, a plasma processing system, and a method for replacing the edge ring. Background Technology

[0002] Patent document 1 discloses a technique of arranging a heat transfer sheet with adhesiveness and flexibility between a focusing ring and a stage in a substrate processing device.

[0003] The substrate processing apparatus disclosed in Patent Document 2 includes: a mounting stage having a base having a substrate mounting surface for mounting a substrate and a focusing ring mounting surface for mounting a focusing ring; and a plurality of positioning pins. The substrate processing apparatus includes lifting pins and a conveying arm. The lifting pins are disposed on the mounting stage in a manner that allows them to extend and retract into the focusing ring mounting surface, lifting the focusing ring at each positioning pin to disengage it from the focusing ring mounting surface. The conveying arm is disposed outside the processing chamber and, via an inlet / outlet disposed within the processing chamber, replaces the focusing ring with the positioning pins attached between itself and the lifting pins.

[0004] The substrate processing apparatus disclosed in Patent Document 3 includes multiple electrodes and a supply unit. The electrodes are disposed within an electrostatic chuck on which the substrate is mounted, in a region corresponding to a focusing ring, and a voltage is applied to the electrostatic chuck to attract the focusing ring. Furthermore, the supply unit supplies a heat medium to the space between the focusing ring, which is disposed on the electrostatic chuck in a manner that surrounds the region on which the substrate is mounted, and the space between the electrostatic chuck and the focusing ring.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent document 1: Japanese Patent Application Publication No. 2016-119334.

[0008] Patent document 2: Japanese Patent Application Publication No. 2011-054933.

[0009] Patent document 3: Japanese Patent Application Publication No. 2016-122740. Summary of the Invention

[0010] The problem the invention aims to solve

[0011] The technology of the present invention maintains the thermal conductivity between the edge ring of the heat transfer plate and the substrate support while improving the peelability of the heat transfer plate from the substrate support.

[0012] Technical means for solving problems

[0013] One aspect of the invention is a substrate support stage having: a substrate mounting surface for mounting a substrate; an annular mounting surface for mounting an edge ring, wherein the edge ring is configured to surround the substrate mounted on the substrate mounting surface; and an electrode for attracting and holding the edge ring to the annular mounting surface by electrostatic force, wherein a heat transfer sheet is attached to the side of the edge ring opposite to the annular mounting surface and is mounted on the annular mounting surface via the heat transfer sheet, wherein a conductive film is formed on the side of the heat transfer sheet opposite to the annular mounting surface, and the edge ring is held to the annular mounting surface by attracting the conductive film of the heat transfer sheet attached to the edge ring by means of the electrostatic force formed by the electrode.

[0014] Invention Effects

[0015] According to the present invention, the thermal conductivity between the edge ring of the heat transfer plate and the substrate support can be maintained while the peelability of the heat transfer plate from the substrate support is improved. Attached Figure Description

[0016] Figure 1 This is a top view showing the general structure of the plasma processing system of this embodiment.

[0017] Figure 2 This is a longitudinal cross-sectional view showing the general structure of the processing module.

[0018] Figure 3 This is a cross-sectional view showing the general structure of the heat transfer plate.

[0019] Figure 4 This is a diagram used to illustrate another example of an edge ring.

[0020] Figure 5 This is another example of a lifting pin.

[0021] Figure 6 This is another example of a lifting pin.

[0022] Figure 7 This is a diagram used to illustrate another example of an edge ring.

[0023] Explanation of reference numerals in the attached figures

[0024] 60 Processing Modules

[0025] 70 Conveying device

[0026] 71 Conveyor Arm

[0027] 100 plasma processing chamber

[0028] 100s plasma processing space

[0029] 101 Wafer Support Stage

[0030] 104a wafer mounting surface

[0031] 104b Ring-mounted surface

[0032] 107 Lifting Pin

[0033] 109 electrode

[0034] 109a electrode

[0035] 109b electrode

[0036] 200 lifting pins

[0037] 210 Lifting Pin

[0038] E edge ring

[0039] E1 edge ring

[0040] E2 edge ring

[0041] T heat transfer plate

[0042] Ta conductive film

[0043] W chip Detailed Implementation

[0044] In the manufacturing processes of semiconductor devices, plasma treatment is performed on substrates such as semiconductor wafers (hereinafter referred to as "wafers") using plasma for etching and film deposition. The plasma treatment is carried out on a substrate support stage placed inside a processing container, with the pressure inside the processing container reduced.

[0045] In addition, during plasma processing, in order to obtain good and uniform processing results in the central and peripheral parts of the substrate, an edge ring is sometimes placed on the substrate support in a manner that surrounds the substrate on the substrate support.

[0046] In addition, temperature control of the substrate is important in plasma processing. The temperature of the substrate support is adjusted by a temperature regulating mechanism, and the substrate is adjusted to the desired temperature by means of the substrate support.

[0047] When using an edge ring, its temperature control is also crucial. This is because the edge ring's temperature fluctuates due to the influence of the plasma, affecting the plasma treatment results at the periphery of the substrate. Therefore, the edge ring's temperature is also regulated using a substrate support. However, even after mirror polishing of both the edge ring and the substrate support, surface roughness remains. Furthermore, the expansion of both the edge ring and the substrate support due to the plasma creates a small space between them. Consequently, when the processing chamber is depressurized by simply placing the edge ring on the substrate support, this space becomes a vacuum insulation layer, reducing thermal conductivity between the edge ring and the substrate support. This makes it difficult to regulate the edge ring's temperature to the desired level using only the substrate support.

[0048] As a solution based on this, a technique of arranging a heat transfer sheet between the edge ring and the substrate support is proposed (see Patent Document 1). In particular, when the heat transfer sheet has adhesiveness and elasticity, the stability of the contact between the heat transfer sheet and the edge ring, as well as the stability of the contact between the heat transfer sheet and the substrate support, increases, thereby improving the thermal conductivity between the edge ring and the substrate support.

[0049] However, when the heat transfer plate is adhesive, a portion of the heat transfer plate remains on the substrate support when the operator detaches the edge ring from it for replacement. This is also the case when replacing the edge ring is done using a lifting pin, as in Patent Document 2. Removing the heat transfer plate when it remains on the substrate support is time-consuming.

[0050] In addition, as a technique for improving the thermal conductivity between the substrate support and the edge ring, a technique is proposed that an electrode is provided in the substrate support to apply a voltage for attracting the edge ring to the substrate support by electrostatic force, and a heat transfer gas is supplied to the space between the substrate support and the edge ring (see Patent Document 3).

[0051] In this technology, the heat transfer plate does not remain on the substrate support when the edge ring is replaced. However, when the flow rate of the heat transfer gas supplied to the space between the substrate support and the edge ring is high, the edge ring may shift. Therefore, the flow rate of the heat transfer gas is limited, and there is room for improvement in the thermal conductivity between the edge ring and the substrate support. For example, in recent years, in order to improve the processing results of plasma treatment and to develop plasma with higher energy, in the above-mentioned technology using heat transfer gas, when the plasma energy is high and the input heat from the plasma to the edge ring is high, it is difficult to control the edge ring to the desired temperature.

[0052] Therefore, the technology of the present invention is to maintain the thermal conductivity between the edge ring of the heat transfer plate and the substrate support while improving the peelability of the heat transfer plate from the substrate support.

[0053] The edge ring, substrate support, plasma processing system, and edge ring replacement method of this embodiment will now be described with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, elements having substantially the same functional structure are labeled with the same reference numerals, thereby omitting redundant descriptions.

[0054] Figure 1 This is a top view showing the general structure of the plasma processing system according to this embodiment. Figure 1 In the plasma processing system 1, a wafer W, which serves as a substrate, is subjected to plasma processing such as etching, film formation, and diffusion.

[0055] like Figure 1 As shown, the plasma processing system 1 includes an atmospheric section 10 and a depressurization section 11, which are connected as a single unit via load locking modules 20 and 21. The atmospheric section 10 has an atmospheric module for performing desired processing on the wafer W under atmospheric pressure. The depressurization section 11 has a depressurization module for performing desired processing on the wafer W under depressurized atmosphere.

[0056] Load locking modules 20 and 21 are configured to connect the loading module 30 of the atmospheric section 10 (described later) and the transport module 50 of the depressurization section 11 (described later) via a gate (not shown). Load locking modules 20 and 21 are configured to temporarily hold the wafer W. Furthermore, load locking modules 20 and 21 are configured to switch the internal atmosphere to atmospheric pressure and depressurized atmosphere (vacuum state).

[0057] The atmospheric section 10 includes a loading module 30 with a transport device 40 described later and load ports 32 for holding hoops 31a and 31b. Hoop 31a is a component capable of holding multiple wafers W, and hoop 31b is a component capable of holding multiple edge rings E. Furthermore, in the loading module 30, an orientation module (not shown) for adjusting the horizontal orientation of the wafers W and edge rings E may be arranged adjacent to a storage module (not shown) for holding multiple wafers W.

[0058] The interior of the loading module 30 is constructed of a rectangular shell, and the interior of the shell is maintained at atmospheric pressure. On one side of the long side of the shell constituting the loading module 30, a plurality of end caps 32 are arranged side-by-side, for example, five. On the other side of the long side of the shell constituting the loading module 30, load locking modules 20 and 21 are arranged side-by-side.

[0059] A conveying device 40 for conveying the wafer W and the edge ring E is provided inside the loading module 30. The conveying device 40 includes: a conveying arm 41 that supports and moves the wafer W and the edge ring E; a rotary table 42 that rotatably supports the conveying arm 41; and a base 43 on which the rotary table 42 is mounted. In addition, a guide rail 44 extending in the length direction of the loading module 30 is provided inside the loading module 30. The base 43 is mounted on the guide rail 44, and the conveying device 40 is configured to be movable along the guide rail 44.

[0060] The depressurization unit 11 includes a transport module 50 for transporting the wafer W and the edge ring E; and a processing module 60, which serves as a plasma processing apparatus for performing desired plasma processing on the wafer W transported from the transport module 50. The interiors of the transport module 50 and the processing module 60 are maintained in a depressurized atmosphere. For each transport module 50, a plurality of processing modules 60, for example, eight, are provided. Furthermore, the number and configuration of the processing modules 60 are not limited by this embodiment and can be arbitrarily set, as long as at least one processing module is provided for replacing the edge ring E. Alternatively, the edge ring E can be stored in the depressurization unit 11. That is, instead of the clamp 31b, or together with the clamp 31b, an edge ring storage module connected to the transport module 50 can be provided to store the edge ring E.

[0061] The interior of the transport module 50 is constructed of a polygonal (pentagonal in the illustrated example) housing, which is connected to the load locking modules 20 and 21 as described above. The transport module 50 transports the wafer W, which is fed into the load locking module 20, to a processing module 60, and discharges the wafer W, which has undergone the desired plasma treatment in the processing module 60, to the atmosphere 10 via the load locking module 21. Furthermore, the transport module 50 transports the edge ring E, which is fed into the load locking module 20, to a processing module 60, and discharges the edge ring E, which is to be replaced within the processing module 60, to the atmosphere 10 via the load locking module 21.

[0062] The wafer W in the processing module 60 undergoes plasma processing, such as etching, film deposition, and diffusion. The processing module 60 can arbitrarily select the module for the target plasma processing. Furthermore, the processing module 60 is connected to the transport module 50 via a gate 61. The structure of this processing module 60 will be described later.

[0063] A conveying device 70 for conveying the wafer W and the edge ring E is provided inside the conveying module 50. The conveying device 70 includes: a conveying arm 71 that serves as a support for supporting and moving the wafer W and the edge ring E; a rotary table 72 that rotatably supports the conveying arm 71; and a base 73 on which the rotary table 72 is mounted. Furthermore, a guide rail 74 extending in the longitudinal direction of the conveying module 50 is provided inside the conveying module 50. The base 73 is mounted on the guide rail 74, and the conveying device 70 is configured to be movable along the guide rail 74.

[0064] In the transport module 50, the wafer W and edge ring E, held within the load locking module 20, are received by the transport arm 71 and fed into the processing module 60. Furthermore, the wafer W and edge ring E, held within the processing module 60, are received by the transport arm 71 and sent out to the load locking module 21.

[0065] Additionally, the plasma processing system 1 includes a control device 80. In one embodiment, the control device 80 processes computer-executable commands that cause the plasma processing system 1 to perform the various steps described herein. The control device 80 can be configured to control other elements of the plasma processing system 1 to perform the various steps described herein. In one embodiment, some or all of the control device 80 may be included in other elements of the plasma processing system 1. The control device 80 may, for example, include a computer 90. The computer 90 may, for example, include a processing unit (CPU) 91, a storage unit 92, and a communication interface 93. The processing unit 91 can be configured to perform various control actions based on a program stored in the storage unit 92. The storage unit 92 may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or combinations thereof. The communication interface 93 can communicate with other elements of the plasma processing system 1 via a communication line such as a LAN (Local Area Network).

[0066] The following describes the wafer processing performed using the plasma processing system 1 configured as described above.

[0067] First, the wafer W is removed from the desired clamp 31a using the conveying device 40 and fed into the load locking module 20. After the wafer W is fed into the load locking module 20, the load locking module 20 is sealed and the pressure is reduced. Then, the interior of the load locking module 20 is connected to the interior of the conveying module 50.

[0068] Next, the wafer W is held in place by the transport device 70 and transported from the load locking module 20 to the transport module 50.

[0069] Next, gate 61 is opened, and wafer W is fed into the desired processing module 60 using the transport device 70. Then, gate 61 is closed, and the processing module 60 performs the desired processing on wafer W. Furthermore, the processing performed on wafer W in this processing module 60 will be described later.

[0070] Next, gate 61 is opened, and the wafer W is delivered from processing module 60 using conveyor 70. Then, gate 61 is closed.

[0071] Next, the wafer W is fed into the load locking module 21 using the conveying device 70. After the wafer W is fed into the load locking module 21, the load locking module 21 is sealed and left open to the atmosphere. Then, the interior of the load locking module 21 is connected to the interior of the loading module 30.

[0072] Next, the wafer W is held by the transport device 40 and sent from the load locking module 21 back to the desired clamp 31a for storage via the loading module 30. Thus, a series of wafer processing steps in the plasma processing system 1 are completed.

[0073] Next, use Figure 2 The processing module 60 will be described below. Figure 2 This is a longitudinal cross-sectional view showing the general structure of the processing module 60.

[0074] like Figure 2 As shown, the processing module 60 includes a plasma processing chamber 100 serving as a processing container, a gas supply unit 130, an RF (Radio Frequency) electrical power supply unit 140, and an exhaust system 150. Furthermore, the processing module 60 also includes a voltage application unit 120 (described later). Figure 3 Additionally, the processing module 60 includes a wafer support stage 101 serving as a substrate support stage and an upper electrode spray head 102.

[0075] The wafer support stage 101 is disposed in the lower region of the plasma processing space 100s within the plasma processing chamber 100, which is configured as a depressurized plasma processing chamber 100. The upper electrode spray head 102 is disposed above the wafer support stage 101 and functions as part of the ceiling of the plasma processing chamber 100.

[0076] The wafer support stage 101 is configured to support the wafer W in the plasma processing space 100s. In one embodiment, the wafer support stage 101 includes a lower electrode 103, an electrostatic chuck 104, an insulator 105, a lifting pin 106, and a lifting pin 107. Although not shown in the figures, the wafer support stage 101 includes a temperature control module configured to adjust at least one of the electrostatic chuck 104 and the wafer W to a target temperature. The temperature control module may include a heater, a flow path, or a combination thereof. A temperature-regulating fluid, such as a refrigerant or a heat transfer gas, can flow through the flow path.

[0077] The lower electrode 103 is formed of a conductive material such as aluminum. In one embodiment, the temperature regulation module described above may also be disposed on the lower electrode 103.

[0078] An electrostatic chuck 104 is a component configured to attract and hold both the wafer W and the edge ring E using electrostatic force, and is disposed on the lower electrode 103. In the electrostatic chuck 104, the upper surface of the central portion is higher than the upper surface of the peripheral portion. The upper surface 104a of the central portion of the electrostatic chuck 104 serves as the substrate mounting surface for the wafer W, and the upper surface 104b of the peripheral portion of the electrostatic chuck 104 serves as the ring mounting surface for the edge ring E. The edge ring E is ring-shaped when viewed from above and is arranged to surround the wafer W placed on the upper surface (hereinafter, the wafer mounting surface) 104a of the central portion of the electrostatic chuck 104. The edge ring E is mounted on the ring mounting surface 104b via a heat transfer plate T. Specifically, the edge ring E is placed on the lower surface of the electrostatic chuck 104, opposite the upper surface (hereinafter, the ring mounting surface) 104b of the periphery of the electrostatic chuck 104, with the heat transfer sheet T pre-attached and formed as an integral part.

[0079] An electrode 108 for adsorbing and holding the wafer W is provided at the center of the electrostatic chuck 104, and an electrode 109 for adsorbing and holding the edge ring E is provided at the periphery of the electrostatic chuck 104. The electrostatic chuck 104 has a structure in which the electrodes 108 and 109 are sandwiched in an insulating component made of insulating material. The electrodes 108 and 109 are connected from the voltage application section 120 (see reference). Figure 3 A voltage is applied to generate an electrostatic force for adsorbing the wafer W and the edge ring E. In this embodiment, the central portion of the electrostatic chuck 104 with electrode 108 and the peripheral portion of electrode 109 are formed as one piece, but the central portion and the peripheral portion may also be separate.

[0080] In addition, the central portion of the electrostatic chuck 104 is formed, for example, with a diameter smaller than that of the wafer W. When the wafer W is placed on the wafer mounting surface 104a, the peripheral portion of the wafer W extends out from the central portion of the electrostatic chuck 104.

[0081] Although not shown in the figure, a gas supply hole is formed on the wafer mounting surface 104a of the electrostatic chuck 104 to supply heat transfer gas to the back side of the wafer W mounted on the wafer mounting surface 104a. Heat transfer gas from a gas supply unit (not shown) is supplied through the gas supply hole. The gas supply unit may also include one or more gas sources and one or more flow controllers. In one embodiment, the gas supply unit is configured, for example, to supply heat transfer gas from the gas source to the heat transfer gas supply hole via a flow controller. The flow controller includes, for example, a mass flow controller or a pressure-controlled flow controller. While a heat transfer gas supply hole is formed on the wafer mounting surface 104a of the electrostatic chuck 104 as described above, a heat transfer gas supply hole may not be formed on the annular mounting surface 104b.

[0082] An edge ring E, mounted on the ring mounting surface 104b, has a step formed on its upper part, and the upper surface of its outer periphery is formed to be higher than the upper surface of its inner periphery. The inner periphery of the edge ring E is formed by drilling into the lower side of the periphery of the wafer W extending from the center of the electrostatic chuck 104. That is, the inner diameter of the edge ring E is formed to be smaller than the outer diameter of the wafer W. Furthermore, the material of the edge ring E is, for example, quartz. The material of the edge ring E can also be silicon (Si) or silicon carbide (SiC).

[0083] The insulator 105 is a cylindrical component made of ceramic or the like, which supports the electrostatic chuck 104. The insulator 105 is formed, for example, with an outer diameter equal to that of the lower electrode 103, and supports the periphery of the lower electrode 103.

[0084] The lifting pin 106 is a columnar component, for example, made of ceramic, capable of extending and retracting into the wafer mounting surface 104a of the electrostatic chuck 104. Three or more lifting pins 106 are spaced apart from each other along the circumference of the electrostatic chuck 104, specifically along the circumference of the wafer mounting surface 104a. The lifting pins 106 are, for example, evenly spaced along the aforementioned circumferential direction. The lifting pins 106 extend vertically.

[0085] The lifting pin 106 is connected to a lifting mechanism 110 that raises and lowers the lifting pin 106. The lifting mechanism 110 includes, for example, a support member 111 that supports a plurality of lifting pins 106; and a drive unit 112 that generates a driving force to raise and lower the support member 111, thereby raising and lowering the plurality of lifting pins 106. The drive unit 112 has a motor (not shown) that generates the driving force described above.

[0086] The lifting pin 106 is inserted into a through hole 113 that extends downward from the wafer mounting surface 104a of the electrostatic chuck 104 to the bottom surface of the lower electrode 103. In other words, the through hole 113 is formed in such a way that it passes through the central part of the electrostatic chuck 104 and the lower electrode 103.

[0087] The lifting pin 107 is a columnar component that can extend and retract into the annular mounting surface 104b of the electrostatic chuck 104, and is made of materials such as alumina, quartz, or SUS. The lifting pins 107 are arranged at intervals along the circumference of the electrostatic chuck 104, specifically along the circumference of the wafer mounting surface 104a and the annular mounting surface 104b. The lifting pins 107 are arranged at equal intervals along the aforementioned circumferential direction. The lifting pins 107 extend vertically and are positioned so that their upper end faces are horizontal. Furthermore, the thickness of the lifting pin 107 is, for example, 1 to 3 mm.

[0088] The lifting pin 107 is connected to the lifting mechanism 114 that drives the lifting pin 107. The lifting mechanism 114 includes, for example, a support member 115 that supports a plurality of lifting pins 107; and a drive unit 116 that generates a driving force to raise and lower the support member 115, thereby raising and lowering the plurality of lifting pins 107. The drive unit 116 has a motor (not shown) that generates the aforementioned driving force.

[0089] The lifting pin 107 is inserted into a through hole 117 that extends downward from the annular mounting surface 104b of the electrostatic chuck 104 to the bottom surface of the lower electrode 103. In other words, the through hole 117 is formed in such a way that it passes through the periphery of the electrostatic chuck 104 and the lower electrode 103.

[0090] The upper electrode spray head 102 is configured to supply one or more processing gases from the gas supply unit 130 to the plasma processing space 100s. In one embodiment, the upper electrode spray head 102 has a gas inlet 102a, a gas diffusion chamber 102b, and a plurality of gas outlets 102c. The gas inlet 102a is in fluid-flowable communication with, for example, the gas supply unit 130 and the gas diffusion chamber 102b. The plurality of gas outlets 102c are in fluid-flowable communication with the gas diffusion chamber 102b and the plasma processing space 100s. In one embodiment, the upper electrode spray head 102 is configured to supply one or more processing gases from the gas inlet 102a through the gas diffusion chamber 102b and the plurality of gas outlets 102c to the plasma processing space 100s.

[0091] The gas supply unit 130 may also include one or more gas sources 131 and one or more flow controllers 132. In one embodiment, the gas supply unit 130 is configured, for example, to supply one or more processing gases from their respective gas sources 131 via their respective flow controllers 132 to the gas inlet 102a. Each flow controller 132 may include, for example, a mass flow controller or a pressure-controlled flow controller. Furthermore, the gas supply unit 130 may include one or more flow modulators that modulate or pulse the flow rate of one or more processing gases.

[0092] The RF power supply unit 140 is configured to supply RF power, such as one or more RF signals, to one or more electrodes, such as the lower electrode 103, the upper electrode spray head 102, or both the lower electrode 103 and the upper electrode spray head 102. This generates plasma from one or more processing gases supplied to the plasma processing space 100s. Therefore, the RF power supply unit 140 can function as at least part of the plasma generation unit, configured to generate plasma from one or more processing gases in the plasma processing chamber. The RF power supply unit 140 includes, for example, two RF generation units 141a and 141b and two matching circuits 142a and 142b. In one embodiment, the RF power supply unit 140 is configured to supply a first RF signal from the first RF generation unit 141a to the lower electrode 103 via the first matching circuit 142a. For example, the first RF signal may have a frequency in the range of 27MHz to 100MHz.

[0093] In another embodiment, the RF power supply unit 140 is configured to supply a second RF signal from the second RF generation unit 141b to the lower electrode 103 via the second matching circuit 142b. For example, the second RF signal may also have a frequency in the range of 400 kHz to 13.56 MHz. Alternatively, a DC (Direct Current) pulse generation unit may be used instead of the second RF generation unit 141b.

[0094] Furthermore, although figures are omitted, other embodiments are considered in this invention. For example, in an alternative embodiment, the RF power supply unit 140 may be configured to supply a first RF signal from the RF generation unit to the lower electrode 103, a second RF signal from another RF generation unit to the lower electrode 103, and a third RF signal from yet another RF generation unit to the lower electrode 103. Additionally, in other alternative embodiments, a DC voltage may be applied to the upper electrode spray head 102.

[0095] Additionally, in various embodiments, the amplitude of one or more RF signals (i.e., a first RF signal, a second RF signal, etc.) may be pulsed or modulated. Amplitude modulation includes pulsed modulation of the RF signal amplitude between an on state and an off state or between two or more different on states.

[0096] The exhaust system 150 can be connected, for example, to an exhaust port 100e located at the bottom of the plasma processing chamber 100. The exhaust system 150 may also include a pressure valve and a vacuum pump. The vacuum pump may include a turbomolecular pump, a roughing pump, or a combination thereof.

[0097] The heat transfer plate T and the voltage application part 120 will be described below. Figure 3 This is a cross-sectional view showing the general structure of the heat transfer plate T.

[0098] The heat transfer plate T is a plate-shaped component. When viewed from above, its shape is the same as that of the edge ring E, which is also ring-shaped. Specifically, its outer diameter is smaller than that of the edge ring E, and its inner diameter is smaller than that of the edge ring E.

[0099] Furthermore, the heat transfer plate T is formed to have high thermal conductivity (e.g., 0.2–5 W / m·K) and high elasticity. For example, in the heat transfer plate T, a heat-resistant organic material is used as the base material, and a large amount of heat-transferring filler is mixed in and dispersed. Examples of heat-resistant organic materials include heat-resistant adhesives containing silicon or rubber. Furthermore, the heat-transferring filler is, for example, alumina in particulate form.

[0100] For example, when the heat transfer plate T is attached to the edge ring E, it gels and becomes adhesive, and is attached to the edge ring E by utilizing its adhesiveness (adhesive force).

[0101] In addition, heat transfer plate T such Figure 3 As shown, a conductive film Ta is formed on the surface opposite to the ring mounting surface 104b.

[0102] The conductive film Ta is a film formed from a conductive material such as a metal. For example, to avoid contamination of the wafer W and the plasma processing chamber 100, aluminum (Al) is used, specifically the same material as the sidewalls and bottom wall of the plasma processing chamber 100.

[0103] The conductive film Ta on the heat transfer plate T can be formed, for example, by bonding a metal foil made of a metallic material using the adhesive properties (adhesive force) of the heat transfer plate T. Alternatively, the conductive film Ta can be formed by sputtering or vapor deposition. Furthermore, the formation of the conductive film Ta on the heat transfer plate T can be performed before or after bonding the heat transfer plate T to the edge ring E. Moreover, the thickness of the conductive film Ta is, for example, as thin as 10 μm or less, preferably the thinnest possible within the formable range. This thinness of the conductive film Ta allows for plastic deformation during adsorption of the edge ring E, preventing gaps between the conductive film Ta and the ring mounting surface 104b. Furthermore, the conductive film Ta preferably has a thermal conductivity higher than that of the heat transfer plate T; if it is as thin as described above, the thermal conductivity of the heat transfer plate T can be even higher.

[0104] The edge ring E with the heat transfer plate T attached in this way is attracted and held on the ring mounting surface 104b by the electrostatic force generated between the conductive film Ta formed on the heat transfer plate T and the electrode 109.

[0105] Electrode 109 is, for example, a bipolar type comprising a pair of electrodes 109a and 109b. A voltage application section 120 is provided for electrodes 109a and 109b.

[0106] The voltage application unit 120 includes, for example, two DC power supplies 121a and 121b and two switches 122a and 122b. DC power supply 121a is connected to electrode 109a via switch 122a, selectively applying a positive or negative voltage to electrode 109a for adsorbing the edge ring E. DC power supply 121b is connected to electrode 109b via switch 122b, selectively applying a positive or negative voltage to electrode 109b for adsorbing the edge ring E.

[0107] Additionally, the voltage application unit 120 includes, for example, a DC power supply 121c and a switch 122c. The DC power supply 121c is connected to the electrode 108 via the switch 122c, and applies a voltage to the electrode 108 for adsorbing the wafer W.

[0108] In addition, in this embodiment, the electrode 109 used to adsorb and retain the edge ring E is a bipolar electrode, but it can also be a unipolar electrode.

[0109] In addition, in this embodiment, an electrode 109 is provided on the electrostatic chuck 104 to attract and hold the edge ring E by electrostatic force. However, it is also possible to apply a DC voltage to the lower electrode 103, for example, to attract and hold the edge ring E by the electrostatic force generated therefrom.

[0110] The following describes an example of wafer processing performed using the processing module 60. Furthermore, in the processing module 60, processes such as etching, film deposition, and diffusion are performed on the wafer W.

[0111] First, the wafer W is fed into the plasma processing chamber 100, and is placed on the electrostatic chuck 104 by the lifting pin 106. Then, a DC voltage is applied to the electrodes 108 of the electrostatic chuck 104 from the DC power supply 121c, thereby electrostatically attracting and holding the wafer W by the electrostatic chuck 104. Furthermore, after the wafer W is fed in, the vacuum system 150 depressurizes the interior of the plasma processing chamber 100 to a specified vacuum level.

[0112] Next, processing gas is supplied from the gas supply unit 130 to the plasma processing space 100s via the upper electrode spray head 102. Furthermore, high-frequency electrical power HF for plasma generation is supplied from the RF power supply unit 140 to the lower electrode 103, thereby exciting the processing gas and generating plasma. At this time, high-frequency electrical power LF for ion attraction can also be supplied from the RF power supply unit 140. Then, plasma processing is performed on the wafer W by the action of the generated plasma.

[0113] When plasma processing ends, the supply of high-frequency power HF from the RF power supply unit 140 and the supply of processing gas from the gas supply unit 130 are stopped. If high-frequency power LF was supplied during plasma processing, the supply of that high-frequency power LF is also stopped. Next, the supply of DC voltage from the DC power supply 121c is stopped, and the adsorption and holding of the wafer W by the electrostatic chuck 104 is stopped.

[0114] Then, the wafer W is raised using the lifting pin 106, causing it to detach from the electrostatic chuck 104. During this detachment, the wafer W can also undergo a de-energization process. The wafer W is then ejected from the plasma processing chamber 100, completing the wafer processing sequence.

[0115] Furthermore, the edge ring E is attracted and held by electrostatic force during wafer processing, specifically both during and after plasma processing. Before and after plasma processing, different voltages are applied to electrodes 109a and 109b using DC power supplies 121a and 121b, creating a potential difference between them. The edge ring E is attracted and held by the electrostatic force corresponding to this potential difference. Conversely, during plasma processing, the same voltage (e.g., a positive voltage) is applied to electrodes 109a and 109b using DC power supplies 121a and 121b, creating a potential difference between the edge ring E, which becomes grounded by the plasma, and electrodes 109a and 109b. The edge ring E is attracted and held by the electrostatic force corresponding to this potential difference. Additionally, during the period when the edge ring E is attracted by electrostatic force, the lifting pin 107 is submerged in the ring mounting surface 104b of the electrostatic chuck 104.

[0116] The following describes an example of the installation process of installing the edge ring E into the processing module 60 using the aforementioned plasma processing system 1. Furthermore, the following process is performed under the control of the control device 80. Additionally, in the following text, the edge ring E, which is pre-formed integrally with the heat transfer plate T, is sometimes referred to as the replacement edge ring E. In this invention, the component after the heat transfer plate T has been removed from the replacement edge ring E is sometimes referred to as the edge ring body.

[0117] First, the conveying arm 71, which holds the replacement edge ring E, is inserted into the depressurized plasma processing chamber 100 via the feed inlet and outlet (not shown) and the replacement edge ring E is conveyed above the ring mounting surface 104b of the electrostatic chuck 104.

[0118] Next, the lifting pin 107 is raised, and the edge ring E is handed over from the conveyor arm 71 to the lifting pin 107.

[0119] Next, the conveyor arm 71 is withdrawn from the plasma processing chamber 100, i.e., the conveyor arm 71 is deflected and the lifting pin 107 is lowered, thereby placing the replacement edge ring E on the ring mounting surface 104b of the electrostatic chuck 104.

[0120] Then, a DC voltage from the voltage application unit 120 is applied to the electrode 109 located at the periphery of the electrostatic chuck 104. The resulting electrostatic force attracts the conductive film Ta of the heat transfer sheet T attached to the replacement edge ring E onto the ring mounting surface 104b. Specifically, different voltages are applied to electrodes 109a and 109b from DC power supplies 121a and 121b. The resulting electrostatic force, corresponding to the potential difference, attracts and holds the conductive film Ta of the heat transfer sheet T attached to the replacement edge ring E onto the ring mounting surface 104b. As a result, the replacement edge ring E can be attracted and held onto the ring mounting surface 104b. Thus, a series of edge ring E installation processes are completed.

[0121] The removal process for the replacement edge ring E is performed in the reverse order of the installation process described above. When removing the replacement edge ring E, a conductive film Ta is formed on the heat transfer plate T, and there is no adhesion between the contact surface of the replacement edge ring E and the ring mounting surface 104b. When the replacement edge ring E is raised using the lifting pin 107, no heat transfer plate T remains on the ring mounting surface 104b. Furthermore, when removing the replacement edge ring E, it is also possible to remove the edge ring E from the plasma processing chamber 100 after cleaning it.

[0122] Furthermore, when installing or removing the replacement edge ring E, the transport of the replacement edge ring E between the clamping ring 31b and the processing module 60 to which the replacement object is to be replaced is performed in the same manner as the transport of the wafer W between the clamping ring 31a and the processing module 60 during the aforementioned wafer processing.

[0123] As described above, the wafer support stage 101 of this embodiment includes: a wafer mounting surface 104a for mounting a wafer W; an annular mounting surface 104b on which an edge ring E is mounted to surround the wafer W mounted on the wafer mounting surface 104a; and an electrode 109 for attracting and holding the edge ring E to the annular mounting surface 104b by electrostatic force. Furthermore, a heat transfer sheet T is attached to the surface of the edge ring E opposite to the annular mounting surface 104b, and is mounted on the annular mounting surface 104b via the heat transfer sheet T. Moreover, a conductive film Ta is formed on the surface of the heat transfer sheet T opposite to the annular mounting surface 104b. Therefore, the heat transfer sheet T is only adhesive on the surface of the edge ring E, and not adhesive on the contact surface that contacts the annular mounting surface 104b. Thus, when the edge ring E is detached from the annular mounting surface 104b, the heat transfer sheet T can be detached together with the edge ring E, and no heat transfer sheet T remains on the annular mounting surface 104b. Furthermore, in this embodiment, the conductive film Ta of the heat transfer sheet T attached to the edge ring E is adsorbed by the electrostatic force formed by the electrode 109, thereby holding the edge ring E on the ring mounting surface 104b of the wafer support 101. Therefore, by the aforementioned electrostatic force, the conductive film Ta is pressed against the ring mounting surface 104b and deformed, thus ensuring that the conductive film Ta adheres tightly to the ring mounting surface 104b without gaps. Therefore, by forming the conductive film Ta, thermal conductivity between the edge ring E and the wafer support 101 is not impeded.

[0124] In this way, according to this embodiment, the thermal conductivity between the edge ring E of the heat transfer sheet T and the wafer support 101 can be maintained, while the peelability of the heat transfer sheet T from the wafer support 101 can be improved.

[0125] As described above, as disclosed in Patent Document 3, when using a heat transfer gas, it is sometimes impossible to control the edge ring to the desired temperature when the input heat from the plasma to the edge ring is large. This is because the edge ring and the wafer support expand due to the input heat, and the gap between them increases, weakening the electrostatic force acting on the edge ring, causing the heat transfer gas to leak out. As a result, the thermal conductivity between the edge ring and the wafer support decreases. In contrast, in this embodiment, even when the edge ring E and the wafer support 101 expand due to the input heat from the plasma without using a heat transfer gas, the heat transfer sheet T and the conductive film Ta can also expand accordingly. Therefore, no gap is formed between the edge ring E and the wafer support 101, and the edge ring E can be controlled to the desired temperature using the wafer support 101.

[0126] Helium can be used as a heat transfer gas, but it is expensive. In this embodiment, expensive helium is not used, thus achieving a low cost.

[0127] Furthermore, according to this embodiment, even when the edge ring E is replaced using the lifting pin 107 and the conveying device 70, no heat transfer sheet remains on the ring mounting surface 104b of the wafer support stage 101. That is, according to this embodiment, the edge ring E can be replaced automatically without the need for an operator.

[0128] Furthermore, in this embodiment, no gas supply hole for supplying heat transfer gas is formed on the annular mounting surface 104b. Therefore, the contact area between the annular mounting surface 104b and the edge ring E is large, resulting in high thermal conductivity between the edge ring E and the wafer support stage 101. By omitting the through hole 117 through which the lifting pin 107 is inserted, and allowing the operator to replace the edge ring E, the contact area between the annular mounting surface 104b and the edge ring E can be further increased, thus further improving thermal conductivity between the edge ring E and the wafer support stage 101.

[0129] Furthermore, in this embodiment, the edge ring E is electrostatically attracted by the conductive film Ta of the heat transfer sheet T adhered to it. Therefore, insulating materials such as quartz can be used as the material of the edge ring E.

[0130] Figure 4 This is a diagram used to illustrate another example of an edge ring. Figure 4 The edge ring E1 has a recess E1a on the surface opposite to the ring mounting surface 104b, which is recessed in a direction spaced apart from the ring mounting surface 104b. A heat transfer plate T is attached to this recess E1a.

[0131] With this structure, the side area of ​​the heat transfer plate T exposed in the plasma processing space for 100 seconds can be reduced. Therefore, it is possible to suppress damage to the heat transfer plate T caused by the plasma.

[0132] Figure 5 and Figure 6 This is another example of a lifting pin. Figure 5 and Figure 6 When viewed from the side, the lifting pins 200 and 210 have cylindrical or prismatic columnar portions 200a and 210a extending vertically at their lower ends. Furthermore, the area of ​​the upper end face, the contact surface that abuts against the edge ring E, is larger than the cross-sectional area of ​​the horizontal section of the columnar portions 200a and 210a. That is, the lifting pins 200 and 210... Figure 2 Compared to the lifting pin 107 shown, the upper end face that abuts against the edge ring E (specifically, the upper end face that abuts against the heat transfer plate T that is integral with the edge ring E) is larger.

[0133] The lifting pin 200 is shaped like an inverted L when viewed from the side, resulting in a larger upper surface. The lifting pin 210 is shaped like a T when viewed from the side, resulting in a larger upper surface. By making the upper surfaces of the lifting pins 200 and 210 larger, damage to the heat transfer fin T can be prevented when the lifting pins 200 and 210 are raised.

[0134] Alternatively, the upper end of the lifting pin can be formed into a ring shape when viewed from above, where its inner diameter is larger than the inner diameter of the edge ring E and its outer diameter is smaller than the outer diameter of the edge ring E.

[0135] Figure 7 This is a diagram used to illustrate another example of an edge ring. Figure 7 The portion of the edge ring E2 that abuts against the lifting pin 107 on the surface opposite to the ring mounting surface 104b does not have a heat transfer plate T and a conductive film Ta formed. This structure prevents damage to the heat transfer plate T and conductive film Ta due to the lifting pin 107.

[0136] The above descriptions illustrate various illustrative embodiments, but the embodiments are not limited to those described above. Various additions, omissions, substitutions, and changes can be made. Furthermore, elements from different embodiments can be combined to form other embodiments.

Claims

1. A substrate support stage, characterized in that, have: The substrate mounting surface on which the substrate is placed; A ring mounting surface for placing an edge ring, wherein the edge ring is configured to surround a substrate mounted on the substrate mounting surface; and Electrodes used to attract and hold the edge ring to the ring mounting surface by electrostatic force. The edge ring has a heat transfer plate attached to the side opposite to the ring mounting surface, and is mounted on the ring mounting surface via the heat transfer plate. When the heat transfer plate is attached to the edge ring, it gels and becomes adhesive, thus securing it to the edge ring using its adhesive properties. A conductive film is formed on the surface of the heat transfer plate opposite to the surface of the ring mounting. The edge ring is held on the ring mounting surface by means of the electrostatic force formed by the electrodes to attract the conductive film of the heat transfer sheet attached to the edge ring.

2. The substrate support stage as described in claim 1, characterized in that: No gas supply hole for supplying heat transfer gas is formed on the ring-mounted surface.

3. The substrate support stage as described in claim 1 or 2, characterized in that: The edge ring has a recess on the surface opposite to the ring mounting surface. The heat transfer plate is attached to the recess.

4. The substrate support stage as described in claim 1 or 2, characterized in that: The edge ring is formed of quartz.

5. The substrate support stage as described in claim 1 or 2, characterized in that: The edge ring is formed of Si or SiC.

6. The substrate support stage as described in claim 1 or 2, characterized in that: The conductive film is formed of Al.

7. The substrate support stage as described in claim 1 or 2, characterized in that: The thickness of the conductive film is less than 10 μm.

8. The substrate support stage as described in claim 1 or 2, characterized in that: It has a lifting component that allows the edge ring to be raised and lowered.

9. The substrate support stage as described in claim 8, characterized in that: The lifting component has a columnar portion extending in the vertical direction at the bottom, and the area of ​​the contact surface that abuts against the edge ring is larger than the cross-sectional area of ​​the columnar portion.

10. The substrate support stage as described in claim 8, characterized in that: The portion of the edge ring that abuts against the lifting component on the surface opposite to the ring mounting surface does not have the heat transfer sheet and the conductive film formed thereon.

11. A plasma processing system, characterized by, include: A plasma processing apparatus comprising: a substrate support stage according to any one of claims 8 to 10; and a processing container configured to house the substrate support stage and be depressurized. A voltage application unit that applies voltage to the electrode; and a lifting mechanism that causes the lifting component to perform plasma treatment on the substrate on the substrate support stage; A conveying device having a support portion that supports the edge ring, such that the support portion is inserted into or withdrawn from the processing container to feed or deliver the edge ring into or out of the processing container; and A control device for controlling the voltage application unit, the lifting mechanism, and the conveying device. The control device controls the voltage application unit, the lifting mechanism, and the conveying device to perform the following: The step of conveying the edge ring supported on the support portion to the substrate support platform; The step of raising the lifting component and transferring the edge ring from the support to the lifting component; After the support portion has been cleared, the lifting component is lowered, and the edge ring is placed on the ring mounting surface via the heat transfer sheet adhered to the edge ring; and The step of applying a voltage to the electrode and using the resulting electrostatic force to attract the conductive film of the heat transfer sheet attached to the edge ring, thereby holding the edge ring on the ring mounting surface.

12. A method for replacing an edge ring within a plasma processing device, characterized in that: The plasma processing device has: It is configured as a decompression-capable processing container; and A substrate support platform disposed inside the processing container. The substrate support stage has: The substrate mounting surface on which the substrate is placed; A ring mounting surface for placing the edge ring, wherein the edge ring is configured to surround a substrate placed on the substrate mounting surface; Electrodes for attracting and holding the edge ring to the ring mounting surface by electrostatic force; and The lifting component that raises and lowers the edge ring. A heat transfer sheet is attached to the side of the edge ring opposite to the ring mounting surface. When the heat transfer sheet is attached to the edge ring, it gels and becomes adhesive, thus adhering to the edge ring using its adhesive properties. A conductive film is formed on the surface of the heat transfer plate opposite to the surface of the ring mounting. The replacement method includes: The step of conveying the edge ring supported on the support portion of the conveying device to the top of the substrate support platform; The step of raising the lifting component and transferring the edge ring from the support to the lifting component; After the support portion has been cleared, the lifting component is lowered, and the edge ring is placed on the ring mounting surface via the heat transfer plate adhered to the edge ring; and The step of applying a voltage to the electrode and using the resulting electrostatic force to attract the conductive film of the heat transfer sheet attached to the edge ring, thereby holding the edge ring on the ring mounting surface.

Images