Wafer Support Device

Abstract

This wafer support device is provided with a dielectric substrate and an RF electrode provided inside the dielectric substrate. The RF electrode is divided into a plurality of zone electrodes arrayed in the planar direction of the dielectric substrate. The wafer support device includes a short-circuit member connecting the plurality of zone electrodes, and a main-feeding rod connected to the short-circuit member from the back side of the dielectric substrate.

Description

[Technical Field]

[0001] The present invention relates to a wafer support device. This application claims priority based on Japanese Patent Application No. 2020-111803, filed on June 29, 2020, the contents of which are incorporated herein by reference. [Background technology]

[0002] BACKGROUND ART A known wafer support table used in semiconductor manufacturing equipment has a ceramic base that incorporates an RF electrode for generating plasma and a heater electrode inside (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 163935 Summary of the Invention [Problem to be solved by the invention]

[0004] As wafer processing temperatures in semiconductor manufacturing equipment rise, wafer support devices must be able to withstand high temperatures. For example, wafer support devices used in wafer processing at temperatures above 400°C must be reliable enough to withstand the thermal stress caused by differences in the thermal expansion coefficients of various parts. In addition, as the power input to the RF electrode increases, damage due to localized heat generation in the RF electrode has become a problem.

[0005] An object of the present invention is to provide a wafer support device that is highly reliable when used at high temperatures. [Means for solving the problem]

[0006] According to a first aspect of the present invention, there is provided a wafer support device comprising a dielectric substrate and an RF electrode provided inside the dielectric substrate. The RF electrode is divided into a plurality of zone electrodes arranged in a planar direction of the dielectric substrate. The device comprises a short-circuit member connecting the plurality of zone electrodes together, and a main power feed rod connected to the short-circuit member from the rear surface of the dielectric substrate.

[0007] The wafer support device according to the first aspect of the present invention preferably includes the following features. Two or more of the following features may also be preferably combined as needed. The RF electrode may be divided into a plurality of zone electrodes arranged in a radial direction with respect to a center position of the dielectric substrate in a plan view.

[0008] The RF electrode may be divided into a plurality of zone electrodes arranged in a circumferential direction about a center position of the dielectric substrate in a plan view.

[0009] The RF electrode may be divided into a plurality of zone electrodes having equal areas.

[0010] The short-circuiting member may be configured to include a plurality of power feed pins extending from each of the plurality of zone electrodes toward the rear surface of the dielectric substrate and exposed on the rear surface of the dielectric substrate, and a short-circuiting electrode located on the rear surface of the dielectric substrate, connecting the plurality of power feed pins to each other, and connected to the main power feed rod.

[0011] The short-circuit electrode may be configured to be fixed to the plurality of power supply pins in a bent state.

[0012] The dielectric substrate may have a heater electrode and an electrostatic chucking electrode inside, the heater electrode being located closer to the back surface of the dielectric substrate than the RF electrode, and the electrostatic chucking electrode being located closer to the wafer mounting surface of the dielectric substrate than the RF electrode. [Effects of the Invention]

[0013] According to one aspect of the present invention, a wafer support device that is highly reliable when used at high temperatures is provided. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a preferred example of a plasma processing apparatus equipped with an electrostatic chuck device according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view showing a preferred example of an RF electrode and a short-circuit member according to an embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a preferred example of a modified electrostatic chuck device. DETAILED DESCRIPTION OF THE INVENTION

[0015] A preferred example of an electrostatic chuck device, which is a preferred embodiment of the wafer support device of the present invention, will be described below with reference to Figures 1 and 2. Note that in all of the following drawings, the dimensions and proportions of each component may be displayed differently as appropriate to make the drawings easier to understand. The number, position, size, members, etc. may be omitted, added, changed, substituted, replaced, or otherwise modified within the scope of the present invention.

[0016] 1 is a schematic cross-sectional view of a plasma processing apparatus including an electrostatic chuck device (wafer support device) according to this embodiment. The plasma processing apparatus 100 includes a vacuum vessel 101 and an electrostatic chuck device 1 fixed inside the vacuum vessel 101. The vacuum vessel 101 has a bottom wall 102, a cylindrical side wall 103 extending upward from the outer circumferential edge of the bottom wall 102, and a top wall 104 fixed to the upper end of the side wall 103 and facing the bottom wall 102 in the vertical direction.

[0017] An electrostatic chuck device 1 is fixed to the bottom of the internal space of a vacuum vessel 101. The electrostatic chuck device 1 is fixed to the inner surface (the upper surface in the figure) of a bottom wall 102. The electrostatic chuck device 1 of this embodiment is placed in the vacuum vessel 101 with a mounting surface (wafer support surface) 2a on which a wafer W is placed facing upward. The arrangement of the electrostatic chuck device 1 is one example, and other arrangements may also be used.

[0018] The bottom wall 102 of the vacuum vessel 101 has an opening 102a penetrating the bottom wall 102 in the thickness direction, and an exhaust port 102b. The electrostatic chuck device 1 closes the opening 102a from the inside (the upper side in the figure) of the vacuum vessel 101. The exhaust port 102b is located on the side of the electrostatic chuck device 1. A vacuum pump (not shown) is connected to the exhaust port 102b.

[0019] The electrostatic chuck device 1 includes a dielectric substrate 2 having a mounting surface 2a on which a wafer W is placed, a support member 3 that supports the dielectric substrate 2, a side cover 4 located on the outer periphery of the support member 3, and a focus ring 5 that is disposed on the upper surface of the dielectric substrate 2 as shown in the figure.

[0020] The dielectric substrate 2 has a circular shape in a plan view. The dielectric substrate 2 is made of a composite sintered body that has mechanical strength and durability against corrosive gases and their plasma. As a dielectric material that constitutes the dielectric substrate 2, ceramics that have mechanical strength and durability against corrosive gases and their plasma are preferably used. As the ceramic that constitutes the dielectric substrate 2, for example, aluminum oxide (Al2O3) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al2O3)-silicon carbide (SiC) composite sintered body, etc. are preferably used.

[0021] It is preferable that a plurality of protrusions (not shown) are formed at predetermined intervals on the mounting surface 2a of the dielectric substrate 2. Each of the plurality of protrusions has a diameter smaller than the thickness of the wafer W. The plurality of protrusions on the mounting surface 2a support the wafer W. The shape of the protrusions can be selected arbitrarily, and may be, for example, cylindrical.

[0022] The support member 3 is a cylindrical member extending from the outer peripheral edge of the back surface 2b of the dielectric substrate 2 toward the bottom wall 102. The back surface 2b is the surface facing the opposite side (the lower side in the figure) to the mounting surface 2a of the dielectric substrate 2. In this embodiment, the dielectric substrate 2 and the support member 3 constitute a single component. The dielectric substrate 2 and the support member 3 may also be separate components.

[0023] The support member 3 has a flange 3a that extends radially outward from the end on the bottom wall 102 side (the lower side in the figure). The flange 3a has an annular shape in a plan view. The support member 3 is fixed to the bottom wall 102 by, for example, screwing the flange 3a and the bottom wall 102 together. The flange 3a is disposed along the periphery of an opening 102a in the bottom wall 102. The gap between the flange 3a and the bottom wall 102 is airtightly sealed by, for example, an O-ring.

[0024] The space inside the support member 3 is connected to the space outside the vacuum vessel 101 via an opening 102a in the bottom wall 102. The back surface 2b of the dielectric substrate 2 is exposed in the space inside the support member 3. An operator can access the back surface 2b of the dielectric substrate 2 through the opening 102a in the bottom wall 102.

[0025] The side cover 4 is a cylindrical member extending in the vertical direction. The side cover 4 covers the outside of the support member 3. In this embodiment, the side cover 4 faces the side end surface 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3 in the radial direction. The side cover 4 protects the side end surface 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3 from plasma. The side cover 4 is made of, for example, aluminum oxide (Al2O3), quartz, or the like. There are no particular limitations on the material of the side cover 4 as long as it has the required plasma resistance. The electrostatic chuck device 1 may also be configured without the side cover 4.

[0026] In this embodiment, the side cover 4 is installed on the upper surface of the flange 3a. The side cover 4 may be fixed to the inner wall of the vacuum vessel 101. An upper end 4a of the side cover 4 is located to the side of the dielectric substrate 2. The side cover 4 has a notch 4b extending along the inner peripheral edge at an inner corner of the upper end 4a. The outer peripheral portion of the focus ring 5 is disposed inside the notch 4b. The height position (vertical position in the figure) of the upper end face 4c of the side cover 4 substantially coincides with the height position of the upper surface 5a of the focus ring 5 and the height position of the upper surface of the wafer W.

[0027] The electrostatic chuck device 1 includes an RF electrode 6 provided inside the dielectric substrate 2, a short-circuit member 7 connected to the RF electrode 6, and a main power feed rod 8 connected to the short-circuit member 7. Note that RF is an abbreviation for "Radio Frequency."

[0028] In this embodiment, the RF electrode 6 serves both as an electrode for generating plasma on the wafer W and as an electrode for electrostatic attraction for fixing the wafer W by electrostatic attraction force. The RF electrode 6 includes a zone electrode for generating plasma and electrostatically attracting the wafer. As shown in FIG. 1, the RF electrode 6 is located on the surface layer of the dielectric substrate 2 on the mounting surface 2a side in the thickness direction thereof. As shown in Fig. 2, the RF electrode 6 is divided into multiple electrodes arranged in the plane direction (horizontal direction) of the dielectric substrate 2. The RF electrode 6 has a first zone electrode 6a located on the mounting surface 2a and a second zone electrode 6b located in the ring suction region 2d around the mounting surface 2a. In this embodiment, the first zone electrode 6a consists of 11 zone electrodes arranged in the plane direction of the dielectric substrate 2. The second zone electrode 6b consists of four zone electrodes arranged in the plane direction of the dielectric substrate 2.

[0029] The first zone electrode 6a is located in a region of the dielectric substrate 2 that overlaps with the mounting surface 2a on which the wafer W is mounted in a planar view. The first zone electrode 6a is composed of multiple zone electrodes arranged in both radial and circumferential directions relative to the center position of the dielectric substrate 2. The number of zone electrodes can be selected arbitrarily. The first zone electrode includes one zone electrode 61, four zone electrodes 62a, 62b, 62c, and 62d, and six zone electrodes 63a, 63b, 63c, 63d, 63e, and 63f. It is preferable that these zone electrodes do not overlap with each other in a planar view. The first zone electrode is preferably, but not limited to, a circular or approximately circular shape as a whole.

[0030] The zone electrode 61 is an electrode that is circular in plan view and is located at the center of the dielectric substrate 2. The four zone electrodes 62a to 62d are each a strip-shaped electrode extending in the circumferential direction. The four zone electrodes 62a to 62d have the same shape and size. The four zone electrodes 62a to 62d are arranged radially outward of the zone electrode 61 at equal intervals in the circumferential direction. The four zone electrodes 64a to 64d are arranged in an annular shape in a plan view.

[0031] The six zone electrodes 63a to 63f are each a strip-shaped electrode extending in the circumferential direction. The six zone electrodes 63a to 63f have the same shape and size. The six zone electrodes 63a to 63f are arranged at equal intervals in the circumferential direction, radially outside the area in which the four zone electrodes 62a to 62d are arranged. The six zone electrodes 63a to 63f are arranged in an annular shape in a plan view.

[0032] The second zone electrode 6b is located on the periphery of the dielectric substrate 2. The second zone electrode 6b is located in a region of the dielectric substrate 2 that overlaps, in a plan view, with the ring adsorption region 2d on which the focus ring 5 is placed. The second zone electrode 6b is capable of adsorbing the focus ring 5. The second zone electrode 6b is preferably annular or approximately annular overall. The number of zone electrodes included in the second zone electrode 6b can be selected arbitrarily. In this embodiment, the second zone electrode 6b is composed of four zone electrodes 64a, 64b, 64c, and 64d arranged in the planar direction of the dielectric substrate 2. Each of the four zone electrodes 64a to 64d is strip-shaped and extends along the periphery of the dielectric substrate 2. The four zone electrodes 64a to 64d have the same shape and size. The four zone electrodes 64a to 64d are arranged at equal intervals along the periphery of the dielectric substrate 2. The four zone electrodes 64a to 64d are arranged in a ring shape in a plan view. It is preferable that these zone electrodes do not overlap each other in a plan view.

[0033] In the electrostatic chuck device 1, the areas of the eleven electrodes constituting the first zone electrode 6a and the four electrodes constituting the second zone electrode 6b are similar to each other. That is, it is preferable that the RF electrode 6 be divided into multiple electrodes having equal areas. This makes the current flowing through the divided multiple zone electrodes uniform. Current concentration in the power supply path from the main power feed rod 8 to the RF electrode 6 is less likely to occur, making the power supply path less likely to be damaged. It is also preferable that these multiple electrodes have approximately the same thickness. Furthermore, it is preferable that the first zone electrode 6a and the second zone electrode 6b do not overlap each other in a plan view.

[0034] The number of divisions of the RF electrode 6, i.e., the area per zone electrode, can be determined arbitrarily depending on the magnitude of the power input to the RF electrode 6. When high power of, for example, 1 kW or more and 10 MHz or more is input as high frequency power for plasma excitation, in the case of an electrostatic chuck device 1 for 300 mm wafers, the RF electrode 6 is preferably divided into 10 to 20 zone electrodes. A more preferable number of divisions of the RF electrode 6 is 13 to 17.

[0035] The arrangement of the multiple zone electrodes that make up the first zone electrode 6a is an example, and other arrangements are also possible. For example, in this embodiment, the first zone electrode 6a is configured to be divided in both the radial and circumferential directions, but the first zone electrode 6a may be divided only in the radial direction or only in the circumferential direction. In this embodiment, the second zone electrode 6b is configured to include multiple zone electrodes 64a-64d arranged in the circumferential direction, but each of the zone electrodes 64a-64d may be further divided in the radial direction. Alternatively, the second zone electrode 6b may be configured to include multiple annular zone electrodes arranged in the radial direction. Each of the multiple annular zone electrodes may be a continuous annular zone electrode.

[0036] 1 and 2, a plurality of feed pins 7b extend from the lower surfaces of the eleven electrodes constituting the first zone electrode 6a and the four electrodes constituting the second zone electrode 6b toward the rear surface 2b of the dielectric substrate 2. The lower end of each feed pin 7b protrudes downward from the rear surface 2b. In this embodiment, one feed pin 7b is connected to each of the thirteen zone electrodes constituting the RF electrode 6. The feed pins 7b are made of a metal material such as aluminum, copper, tungsten, or kovar.

[0037] The short-circuit electrode 7a is made of a thin metal plate. The short-circuit electrode 7a is made of a metal material such as nickel, aluminum, or copper. As shown in FIG. 2, the short-circuit electrode 7a has a plurality of (eight) strip-shaped electrodes 71-78 extending radially outward from the center of the dielectric substrate 2. In plan view, the strip-shaped electrodes 71-78 overlap one or more power feed pins 7b. Each of the strip-shaped electrodes 71-78 has a through-hole into which the power feed pin 7b is inserted.

[0038] The short-circuit electrode 7a is fastened to a plurality of power feed pins 7b exposed on the back surface 2b of the dielectric substrate 2. In this embodiment, each power feed pin 7b is inserted into a through hole in the short-circuit electrode 7a. Each power feed pin 7b has a male thread portion at its lower end. The short-circuit electrode 7a is fixed to the back surface of the dielectric substrate 2 by a nut 7c that screws onto the male thread portion of the power feed pin 7b. The multiple nuts 7c also electrically connect the short-circuit electrode 7a and the multiple power feed pins 7b. With this configuration, the short-circuit electrode 7a is electrically connected to the first zone electrode 6a and the second zone electrode 6b. The nut 7c may be made of the same metal material as the power feed pin 7b, but the power feed pin 7b and the nut 7c may be made of different materials.

[0039] A main power feed rod 8 is fixed to the power feed pin 7b located at the center of the back surface 2b of the dielectric substrate 2. In this embodiment, the main power feed rod 8 is a cylindrical conductive member. The main power feed rod 8 is made of a metal material such as aluminum, copper, or stainless steel. In this embodiment, the main power feed rod 8 has a base material made of a stainless steel rod or pipe with a thin Ni plating film on the surface. The main power feed rod 8 has a female thread portion that opens onto the end face (upper end face) facing the dielectric substrate 2. The male thread portion at the lower end of the power feed pin 7b is screwed into the female thread portion of the main power feed rod 8.

[0040] The center of the short-circuit electrode 7a is fixed between the main power feed rod 8 and the dielectric substrate 2. The main power feed rod 8 is connected to the short-circuit electrode 7a at the end face on the dielectric substrate 2 side. This electrically connects the main power feed rod 8 to the first zone electrode 6a and the second zone electrode 6b via the short-circuit electrode 7a and the power feed pin 7b.

[0041] In this embodiment, the short-circuit electrode 7a is fixed to the multiple power supply pins 7b in a bent state, as shown in Fig. 1. That is, the short-circuit electrode 7a, which is a thin metal plate, is held in a bent state between the fastening positions with the dielectric substrate 2. The dimensions of the short-circuit electrode 7a change with temperature changes during use, but in this embodiment, the amount of deflection of the short-circuit electrode 7a changes with the change in dimension, reducing the stress acting from the short-circuit electrode 7a on the power feed pin 7b. This allows for a connection between the short-circuit electrode 7a and the power feed pin 7b, or between the power feed pin 7b and the zone electrode.

[0042] A power supply unit 110 is connected to the main power feed rod 8. The power supply unit 110 includes a high-frequency power supply 111 for plasma excitation, a matching box 112, a DC power supply 113 for electrostatic attraction, and a resistor 114. The high-frequency power supply 111 for plasma excitation is electrically connected to the main power feed rod 8 via the matching box 112. The DC power supply 113 for electrostatic attraction is electrically connected to the main power feed rod 8 via the resistor 114.

[0043] The focus ring 5 is disposed in an annular ring suction region 2d surrounding the mounting surface 2a. Although there is a step between the mounting surface 2a and the annular ring suction region 2d, a flat structure without the step may also be used. In the dielectric substrate 2 of this embodiment, a stepped surface facing radially outward is provided at the boundary between the mounting surface 2a and the ring suction region 2d. In other words, the upper surface of the ring suction region 2d is located below the mounting surface 2a. As shown in FIG. 1 , the outer periphery of the focus ring 5 disposed in the ring suction region 2d protrudes radially outward beyond the dielectric substrate 2. The outer periphery of the focus ring 5 protruding outward from the dielectric substrate 2 is disposed within the notch 4b of the side cover 4. The height (vertical position) of the upper surface of the focus ring 5 substantially coincides with the height of the upper surface of the wafer W mounted on the mounting surface 2a.

[0044] Focus ring 5 is made of, for example, a material having electrical conductivity equivalent to that of wafer W placed on mounting surface 2a. Specifically, silicon, silicon carbide, quartz, alumina, or the like can be used as the material for focus ring 5. By providing focus ring 5, the electrical environment relative to the plasma at the peripheral portion of wafer W can be made roughly the same as that of wafer W. This reduces the likelihood of differences or biases in plasma processing between the center and peripheral portions of wafer W.

[0045] 1, the electrostatic chuck device 1 has a heater electrode 9 inside the dielectric substrate 2. The heater electrode 9 is located between the RF electrode 6 and the rear surface 2b in the thickness direction of the dielectric substrate 2. The heater electrode 9 is electrically connected to a heater power supply 120. The plasma processing device 100 controls the power input from the heater power supply 120 to the heater electrode 9 to control heating of the wafer W.

[0046] The heater electrode 9 may be divided into a plurality of heater zone electrodes arranged in the planar direction of the dielectric substrate 2. The shape and arrangement of the heater zone electrodes are not particularly limited. That is, the heater electrode 9 may be divided in the radial direction, the circumferential direction, or both the radial and circumferential directions. In this embodiment, the heater electrode 9 is located inside the dielectric substrate 2, but the heater electrode 9 may also be fixed to the outside of the dielectric substrate 2.

[0047] In addition to the heater electrode 9, the electrostatic chuck device 1 may also include a temperature adjustment device that is in contact with the outer surface of the dielectric substrate 2. As the temperature adjustment device, a liquid-cooled base having a coolant flow path therein can be disposed. The electrostatic chuck device 1 may also be configured without the heater electrode 9.

[0048] The RF electrode 6 and the heater electrode 9 are preferably formed from conductive ceramics such as aluminum oxide-tantalum carbide (Al2O3-Ta4C5) conductive composite sintered compact, aluminum oxide-tungsten (Al2O3-W) conductive composite sintered compact, aluminum oxide-silicon carbide (Al2O3-SiC) conductive composite sintered compact, aluminum nitride-tungsten (AlN-W) conductive composite sintered compact, aluminum nitride-tantalum (AlN-Ta) conductive composite sintered compact, yttrium oxide-molybdenum (Y2O3-Mo) conductive composite sintered compact, or a high-melting point metal such as tungsten (W), tantalum (Ta), molybdenum (Mo), etc.

[0049] The thickness of the RF electrode 6 and the heater electrode 9 is not particularly limited, but may be, for example, 0.1 μm or more and 100 μm or less. The thickness of the RF electrode 6 and the heater electrode 9 is more preferably 5 μm or more and 20 μm or less. If the thickness of the RF electrode 6 and the heater electrode 9 is less than 0.1 μm, it becomes difficult to ensure sufficient conductivity. If the thickness of the RF electrode 6 and the heater electrode 9 exceeds 100 μm, cracks are likely to occur at the bonding interface between the RF electrode 6 and the dielectric substrate 2 and at the bonding interface between the heater electrode 9 and the dielectric substrate 2 due to the difference in thermal expansion coefficient between the RF electrode 6 and the heater electrode 9 and the dielectric substrate 2.

[0050] As described above, in the electrostatic chuck device 1 of this embodiment, the RF electrode 6 is divided into a plurality of zone electrodes, and the RF electrode 6 and the main power feed rod 8 are electrically connected via the short-circuit member 7 that connects the plurality of zone electrodes together. According to this configuration, the RF electrode 6 to which power is supplied from one main power feed rod 8 is divided into a plurality of zone electrodes 61, 62a to 62d, 63a to 63f, and 64a to 64d, thereby reducing the current flowing through each zone electrode. This makes it difficult for current to concentrate at the connection between the short-circuit member 7 and the zone electrodes, making it easier to avoid damage to the connection.

[0051] In this embodiment, zone electrodes 62a to 62d are arranged in a circular ring shape around the zone electrode 61. Furthermore, zone electrodes 63a to 63f are arranged in a circular ring shape around the zone electrodes 62a to 62d. Furthermore, zone electrodes 64a to 64d are arranged in a circular ring shape around the zone electrodes 63a to 63f. That is, the RF electrode 6 is divided into a plurality of zone electrodes arranged in a radial direction with respect to the center position of the dielectric substrate 2 in a plan view. This configuration can reduce the radial bias of the electric field strength at the RF electrode 6. The radial distribution of the plasma excited on the dielectric substrate 2 can be made uniform.

[0052] In this embodiment, the zone electrodes 62a to 62d, the zone electrodes 63a to 63f, and the zone electrodes 64a to 64d are each arranged at equal intervals in the circumferential direction within an annular region. That is, the RF electrode 6 is divided into a plurality of zone electrodes arranged in the circumferential direction with respect to the center position of the dielectric substrate 2 in a plan view. This configuration can reduce the circumferential bias of the electric field strength in the RF electrode 6. The circumferential distribution of the plasma excited on the dielectric substrate 2 can be made uniform.

[0053] In this embodiment, the short-circuiting member 7 includes a plurality of feed pins 7b that extend from each of the plurality of zone electrodes 61, 62a to 62d, 63a to 63f, and 64a to 64d toward the back surface 2b of the dielectric substrate 2 and are exposed on the back surface 2b of the dielectric substrate 2, and a short-circuiting electrode 7a that is located on the back surface 2b of the dielectric substrate 2, connects the plurality of feed pins 7b to each other, and is connected to the main feed rod 8. With this configuration, the short-circuiting electrode 7a is located outside the dielectric substrate 2 and is connected to the RF electrode 6 via the relatively long feed pin 7b. Therefore, even if the short-circuiting electrode 7a expands and contracts due to temperature changes, stress due to dimensional changes in the short-circuiting electrode 7a is less likely to act on the connection between the feed pin 7b and the RF electrode 6, and damage can be more effectively suppressed.

[0054] Furthermore, since the short-circuiting electrode 7a is located outside the dielectric substrate 2, it is easy to cool the short-circuiting electrode 7a. This can suppress the temperature rise of the entire short-circuiting member 7, thereby reducing the thermal stress acting on the connection between the zone electrode and the power feed pin 7b. Because the short-circuiting electrode 7a can be directly air- or liquid-cooled, it is possible to operate in a manner in which the short-circuiting electrode 7a is cooled only during plasma excitation, for example.

[0055] In the present embodiment, as one aspect of the wafer support device, an electrostatic chuck device 1 in which the RF electrode 6 also serves as an electrostatic adsorption electrode has been described. However, the wafer support device of the present invention may also be used in a configuration that does not have an electrostatic chuck function.

[0056] (Variation) FIG. 3 is a partial cross-sectional view showing a modified electrostatic chuck device 1A. In FIG. 3, components denoted by the same reference numerals as those in FIGS. 1 and 2 are components common to the electrostatic chuck device 1 of the embodiment.

[0057] The electrostatic chuck device 1A of this modification has an electrostatic chucking electrode 10 inside the dielectric substrate 2, closer to the mounting surface 2a than the RF electrode 6. The electrostatic chucking electrode 10 has a first electrostatic chucking electrode 10a overlapping the mounting surface 2a in a plan view and a second electrostatic chucking electrode 10b overlapping the ring chucking region 2d in a plan view. A common power supply may be connected to the first electrostatic chucking electrode 10a and the second electrostatic chucking electrode 10b, or separate power supplies may be connected to them. The height positions (vertical positions) of the first electrostatic chucking electrode 10a and the second electrostatic chucking electrode 10b may be the same or different from each other.

[0058] In the modified electrostatic chuck device 1A, the RF electrode 6 is also divided into multiple zone electrodes. For convenience, FIG. 3 schematically illustrates an example in which the RF electrode 6 is divided into four zone electrodes 65, 66, 67, and 68. These zone electrodes preferably do not overlap each other in a planar view, but this is not a limitation; they may at least partially overlap. A short-circuit electrode 7a is connected to each of the four zone electrodes 65-68 via a power feed pin 7b. The short-circuit electrode 7a is connected to a main power feed rod 8 located in the center of the back surface 2b of the dielectric substrate 2. The three zone electrodes 65-67 are preferably located within a region overlapping the mounting surface in a planar view (first zone electrodes), but this is not a limitation. In FIG. 3, the zone electrodes 65-67 are all positioned at the same height when viewed cross-sectionally, but this is not a limitation as needed.

[0059] In the modified electrostatic chuck device 1A, the outermost zone electrode 68 (third zone electrode) overlaps both the outer periphery of the wafer W and the focus ring 5 in a plan view. In the modified example shown in FIG. 3 , there is no step between the mounting surface 2a and the annular ring-shaped attraction region 2d, the upper surface of the dielectric substrate 2 is uniformly flat, and the focus ring 5 and the wafer W have approximately the same thickness. By arranging the outermost zone electrode 68 of the dielectric substrate 2 so as to straddle the boundary between the outer periphery of the wafer W and the focus ring 5, it becomes easier to excite a uniform plasma above the outer periphery of the wafer W and the focus ring 5. Note that the step may be eliminated if necessary. That is, the upper surface of the dielectric substrate 2 does not have to be uniformly flat, or there may be no step between the mounting surface 2a and the annular ring-shaped attraction region 2d.

[0060] In the modified electrostatic chuck device 1A, the dielectric substrate 2 and the support member 3 are separate members. The dielectric substrate 2 and the support member 3 are fixed to each other by a bonding material 12 that extends in the circumferential direction along the outer circumferential surfaces. The bonding material 12 may be, for example, a brazing material or a ceramic spray material. The support member 3 has a flange that extends radially inward from an end, and the end of the flange overlaps the inner end of the bottom wall 102 in a plan view.

[0061] The electrostatic chuck device 1A of the above-described modified example has a heater electrode 9 and an electrostatic attraction electrode 10 inside the dielectric substrate 2. The heater electrode 9 is located closer to the back surface 2b of the dielectric substrate 2 than the RF electrode 6. The electrostatic attraction electrode 10 is located closer to the wafer mounting surface of the dielectric substrate than the RF electrode 6. With this configuration, the RF electrode 6 for plasma excitation and the electrostatic attraction electrode 10 for electrostatic attraction can be driven by separate power supplies.

[0062] The electrostatic chuck device 1A of the modified example can be used in place of the electrostatic chuck device 1 shown in Fig. 1. The configuration of the electrostatic chuck device can be selected depending on the configuration of the plasma processing device 100, the type of wafer W to be placed, the state of the excited plasma, etc. [Industrial Applicability]

[0063] The present invention can provide a wafer support device that is highly reliable when used at high temperatures, and a high-temperature electrostatic chuck stage to which high-power, high-frequency waves can be applied. [Explanation of symbols]

[0064] 1...Electrostatic chuck device (wafer support device) 2...Dielectric substrate 2a...Placement surface 2b…Back side 2c…Side end surface 2d...Ring adsorption area 3...Support member 3a...Flange 3b…Outer surface 4...Side cover 4a...Top end 4b...Notch 4c...Upper end face 5...Focus ring 5a...Top of focus ring 6...RF electrode 6a...First zone electrode 6b...Second zone electrode 7...Short-circuit member 7a...Short-circuit electrode 7b...Power supply pin 7c...nut 8…Main power supply rod 9...Heater electrode 10...Electrostatic adsorption electrode 10a...first electrostatic chucking electrode 10b...Second electrostatic chucking electrode 12...Joining material 61, 62a to 62d, 63a to 63f, 64a to 64d, 65 to 68...Zone electrodes 71~78...Strip electrodes 100...Plasma processing apparatus 101...Vacuum container 102...Bottom wall 102a...Opening 102b...Exhaust port 102c...Sealing material 103…Side wall 104...Top wall 110...Power supply device 111...High frequency power supply 112...matching box 113…DC power supply 114...Resistance 120...Heater power supply W...wafer HRF...High frequency (high frequency power supply)

Claims

1. A wafer support device comprising: a dielectric substrate; and an RF electrode provided inside the dielectric substrate, the RF electrode is divided into a plurality of zone electrodes arranged in a planar direction of the dielectric substrate, a short-circuit member connecting the plurality of zone electrodes to each other; a main power feed rod connected to the short-circuit member from the rear surface side of the dielectric substrate; having Wafer support device.

2. the RF electrode is divided into a plurality of zone electrodes arranged in a radial direction with respect to a center position of the dielectric substrate in a plan view; The wafer support device of claim 1 .

3. the RF electrode is divided into a plurality of zone electrodes arranged in a circumferential direction with respect to a center position of the dielectric substrate in a plan view; 3. The wafer support device according to claim 1 or 2.

4. The RF electrode is divided into a plurality of zone electrodes having equal areas. The wafer support device according to any one of claims 1 to 3.

5. The short-circuit member is a plurality of feed pins extending from each of the plurality of zone electrodes toward the rear surface side of the dielectric substrate and exposed on the rear surface of the dielectric substrate; a short-circuit electrode located on the back surface of the dielectric substrate, connecting the plurality of power feed pins to each other and connected to the main power feed rod; having The wafer support device according to any one of claims 1 to 4.

6. the short-circuit electrode is fixed to the plurality of power supply pins in a deflected state; 6. The wafer support device of claim 5.

7. a heater electrode and an electrostatic chucking electrode are provided inside the dielectric substrate; the heater electrode is located closer to the back surface of the dielectric substrate than the RF electrode, the electrostatic chucking electrode is located closer to the wafer mounting surface of the dielectric substrate than the RF electrode; The wafer support device according to any one of claims 1 to 6.

8. The RF electrode includes a plurality of zone electrodes for generating plasma and electrostatically attracting a wafer. The wafer support device of claim 1 .

9. 7. The wafer support device according to claim 6, wherein the short-circuiting electrode comprises a plurality of strip-shaped electrodes extending radially outward from the center of the dielectric substrate.

10. The dielectric substrate is a wafer mounting surface; an annular region surrounding the wafer mounting surface, the upper surface of which is located below the wafer mounting surface; The RF electrode, in plan view, a first zone electrode located in a region overlapping the wafer mounting surface in a plan view; a second zone electrode located in a region overlapping the annular region in a plan view; The wafer support device of claim 1 .

11. The first zone electrode is a centrally located circular electrode; The electrode includes a plurality of strip-shaped electrodes arranged in the circumferential direction and the radial direction. The wafer support device of claim 10.

12. The second zone electrode includes a plurality of strip-shaped electrodes arranged in the circumferential direction. The wafer support device of claim 10.

13. The first zone electrode and the second zone electrode are located at different heights. The wafer support device of claim 10.

14. The dielectric substrate is a wafer mounting surface; a ring-shaped region surrounding the wafer mounting surface, the upper surface of which is at the same height as the wafer mounting surface; a step is provided between the wafer mounting surface and the annular region; The RF electrode is a first zone electrode located in a region overlapping with a wafer mounting surface of the dielectric substrate in a plan view; a third zone electrode located in a region overlapping both the wafer mounting surface and the annular region in a plan view; The wafer support device of claim 1 .

15. The first zone electrode and the third zone electrode are at the same height position.

15. The wafer support device of claim 14.

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