Electrostatic chuck device

Abstract

An electrostatic chuck device provided with: an electrostatic chuck plate having a dielectric substrate, which has a placement surface on which a wafer is placed, and an attraction electrode, which is positioned in the interior of the dielectric substrate; a metal base for supporting the electrostatic chuck plate from the rear-surface side, which is on the opposite side from the placement surface; and a focus ring that is installed at the outer peripheral portion of the electrostatic chuck plate, and surrounds the placement surface. The electrostatic chuck plate has, on the surface on the same side as the placement surface, a ring attraction area that is attracted to the focus ring, and has, on the rear surface on the opposite side from the placement surface, a base attraction area that is attracted to the metal base.

Description

Technical Field

[0001] The present invention relates to an electrostatic chuck device. This application claims priority based on Japanese Patent Application No. 2020-111804 filed in Japan on June 29, 2020, and incorporates the content herein by reference.

Background Art

[0002] As an electrostatic chuck device for supporting a semiconductor wafer, for example, as described in Patent Document 1, a configuration in which an electrostatic chuck capable of adsorbing a focus ring is installed on a metal susceptor is known. A power supply device for plasma generation is connected to the susceptor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] With the increase in the wafer processing temperature in a semiconductor manufacturing apparatus, an electrostatic chuck device capable of high-temperature processing is required. Specifically, an electrostatic chuck device used for wafer processing at high temperatures is required to have reliability that can withstand thermal stress generated by the difference in the coefficient of thermal expansion of each part. However, in conventional electrostatic chuck devices, there have been problems such as peeling of the adhesion part of the device due to thermal stress.

[0005] An object of the present invention is to provide a wafer support device having excellent reliability during high-temperature use.

Means for Solving the Problems

[0006] According to a first aspect of the present invention, there is provided an electrostatic chuck device including a dielectric substrate having a mounting surface on which a wafer is placed, an electrostatic chuck plate having a suction electrode located inside the dielectric substrate, a metal base supporting the electrostatic chuck plate from the back side opposite to the mounting surface, and a focus ring installed at an outer peripheral portion of the electrostatic chuck plate and surrounding the mounting surface. The electrostatic chuck plate has a ring suction region that is suctioned to the focus ring on a surface on the same side as the mounting surface, and a base suction region that is suctioned to the metal base on a back surface on the opposite side of the mounting surface.

[0007] The electrostatic chuck device according to the first aspect of the present invention preferably includes the features described below. It is also preferable to combine two or more of the following features as necessary. The base suction region of the electrostatic chuck plate and / or one or both of the surfaces of the metal base facing the base suction region may be configured to have a plurality of protrusions distributed in the plane direction of the electrostatic chuck plate.

[0008] The distribution density of the plurality of protrusions may be different between the region of the base suction region that overlaps with the mounting surface in plan view and the region of the base suction region that overlaps with the ring suction region in plan view.

[0009] The suction electrode may be configured to include a first electrode portion located in a surface layer portion on the mounting surface side of the dielectric substrate, a second electrode portion located in a surface layer portion on the metal base side of the dielectric substrate, and a connection pin connecting the first electrode portion and the second electrode portion inside the dielectric substrate.

[0010] The suction electrode may be configured to have a third electrode portion located on the outer peripheral side of the first electrode portion and in the surface layer portion of the ring suction region.

[0011] The electrostatic chuck plate may have a step between the placement surface and the ring adsorption region, and the surface of the ring adsorption region facing the focus ring may be located closer to the metal base than the placement surface.

[0012] The electrostatic chuck plate may have a base fixing portion fixed to the metal base at the central portion of the back surface in a plan view, and the base adsorption region may be arranged to surround the base fixing portion.

Advantages of the Invention

[0013] According to one aspect of the present invention, an electrostatic chuck device excellent in reliability during high-temperature use is provided.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0015] Hereinafter, preferred examples of each embodiment of the electrostatic chuck device of the present invention will be described with reference to the drawings. In all the following drawings, for ease of viewing, the dimensions, ratios, etc. of each component may be appropriately shown as different. Within the scope not departing from the gist of the present invention, numbers, positions, sizes, members, etc. can be omitted, added, changed, replaced, exchanged, or otherwise modified.

[0016] (First Embodiment) FIG. 1 is a schematic cross-sectional view of a plasma processing apparatus including the electrostatic chuck device of the present embodiment. FIG. 2 is a plan view of the electrostatic chuck plate. The plasma processing apparatus 100 includes a vacuum chamber 101 and an electrostatic chuck device 1 fixed inside the vacuum chamber 101. The vacuum chamber 101 has a bottom wall 102, a cylindrical side wall 103 extending upward from the outer peripheral end 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] The electrostatic chuck device 1 is fixed to the bottom of the internal space of the vacuum chamber 101. The electrostatic chuck device 1 is fixed to the inner surface (the upper surface shown in the figure) of the bottom wall 102. The electrostatic chuck device 1 of the present embodiment is disposed in the vacuum chamber 101 with the placement surface 2a on which the wafer W is placed facing upward. The arrangement form of the electrostatic chuck device 1 is an example, and other arrangement forms may be used.

[0018] The bottom wall 102 of the vacuum chamber 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 shown in the figure) of the vacuum chamber 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 an electrostatic chuck plate 10 that adsorbs and supports the wafer W and a metal base 11 that supports the electrostatic chuck plate 10. A focus ring 5 that surrounds the placement surface 2a (wafer W) in plan view is disposed on the outer peripheral portion of the upper surface of the electrostatic chuck plate 10.

[0020] The electrostatic chuck plate 10 includes a dielectric substrate 2 having a mounting surface 2a on which the wafer W is placed, and a suction electrode 6 located inside the dielectric substrate 2. The dielectric substrate 2 is circular in plan view. The dielectric substrate 2 is made of a composite sintered body having mechanical strength and durability against corrosive gases and their plasmas. As the dielectric material constituting the dielectric substrate 2, ceramics having mechanical strength and durability against corrosive gases and their plasmas are preferably used. Examples of the ceramics constituting the dielectric substrate 2 include aluminum oxide (Al 2 O 3 ) sintered body, aluminum nitride (AlN) sintered body, aluminum oxide (Al 2 O 3 )-silicon carbide (SiC) composite sintered body, etc. are preferably used.

[0021] The upper surface of the dielectric substrate 2 is the mounting surface 2a on which the wafer W is placed. A plurality of protrusions 21 are formed on the mounting surface 2a at predetermined intervals. Each of the plurality of protrusions 21 has a diameter smaller than the thickness of the wafer W. The plurality of protrusions 21 on the mounting surface 2a support the wafer W. The shape of the protrusion can be arbitrarily selected, for example, a cylindrical shape.

[0022] The electrostatic chuck plate 10 has a ring suction region 2d on the radially outer side of the mounting surface 2a of the dielectric substrate 2. In the case of this embodiment, the upper surface of the ring suction region 2d is located lower than the mounting surface 2a in the illustrated vertical direction. A focus ring 5 is disposed on the ring suction region 2d. As shown in FIG. 1, the outer peripheral portion of the focus ring 5 disposed in the ring suction region 2d protrudes radially outward from the dielectric substrate 2. The outer peripheral portion of the focus ring 5 protruding outward from the dielectric substrate 2 is disposed in the notch 4b of the side cover 4 described later. The height position (vertical position) of the upper surface of the focus ring 5 substantially coincides with the height position of the upper surface of the wafer W placed on the mounting surface 2a.

[0023] The focus ring 5 is formed of a material having electrical conductivity equivalent to that of the wafer W placed on the placement surface 2a, for example. Specifically, silicon, silicon carbide, quartz, alumina, etc. can be used as the constituent material of the focus ring 5. By disposing the focus ring 5, in the peripheral portion of the wafer W, the electrical environment with respect to the plasma can be made substantially consistent with that of the wafer W. Thereby, the difference and bias in plasma processing between the central portion and the peripheral portion of the wafer W are less likely to occur.

[0024] The suction electrode 6 is located inside the dielectric substrate 2. The suction electrode 6 includes two first electrode portions 61 located in the surface layer portion on the placement surface 2a side of the dielectric substrate 2, two second electrode portions 62 located in the surface layer portion on the metal base 11 side of the dielectric substrate 2, and a plurality of connection pins 63 that connect the first electrode portion 61 and the second electrode portion 62 inside the dielectric substrate 2. Note that the surface layer portion may mean a position close to the surface and may not be exposed on the surface.

[0025] As shown in FIG. 2, the two first electrode portions 61 are each semicircular in plan view. The two first electrode portions 61 are arranged in the plane direction of the dielectric substrate 2. The two first electrode portions 61 are arranged with their linear edges facing each other, and together constitute a circular bipolar electrode. The two first electrode portions 61 are arranged in a region that overlaps the placement surface 2a in plan view.

[0026] The two second electrode portions 62 are each semicircular in plan view. The two second electrode portions 62 are arranged in the plane direction of the dielectric substrate 2. The two second electrode portions 62 are arranged with their linear edges facing each other, and together constitute a circular bipolar electrode. The planar area of the second electrode portion 62 is larger than the planar area of the first electrode portion 61. The second electrode portion 62 extends radially outward of the first electrode portion 61 in plan view. The two second electrode portions 62 are arranged in a region that overlaps the placement surface 2a and the ring suction region 2d in plan view.

[0027] The connection pin 63 is located between the first electrode portion 61 and the second electrode portion 62 that face each other in the vertical direction. The upper end of the connection pin 63 is connected to the lower surface of the first electrode portion 61. The lower end of the connection pin 63 is connected to the upper surface of the second electrode portion 62. As shown in FIG. 2, the electrostatic chuck plate 10 has 18 connection pins 63. The number of connection pins 63 is not particularly limited and can be appropriately arranged according to, for example, the planar area of the adsorption electrode 6. When high-frequency power is input to the adsorption electrode 6, since the high-frequency current easily flows along the outer peripheral portion of the electrode, the plurality of connection pins 63 may be arranged only on the outer peripheral portion of the adsorption electrode 6.

[0028] The electrostatic chuck plate 10 has a gas hole 2e that penetrates the dielectric substrate 2 in the vertical direction. The first electrode portion 61 and the second electrode portion 62 have through holes at positions corresponding to the gas hole 2e, and the first electrode portion 61 or the second electrode portion 62 does not expose on the inner wall surface of the gas hole 2e. The gas hole 2e may be provided at two or more locations.

[0029] The back surface 2b of the dielectric substrate 2 faces the upper surface of the metal base 11 in the vertical direction. In the case of this embodiment, the electrostatic chuck plate 10 can be adsorbed to the metal base 11 by energizing the adsorption electrode 6. In this embodiment, substantially the entire back surface 2b of the dielectric substrate 2 is a base adsorption region 2f that adsorbs to the metal base 11. A plurality of protrusions 22 are formed on the back surface 2b of the dielectric substrate 2 at predetermined intervals. Each of the plurality of protrusions 22 has a diameter smaller than the thickness of the wafer W. The plurality of protrusions 22 on the back surface 2b form a narrow space between the metal base 11 and the dielectric substrate 2. The shape of the protrusion can be arbitrarily selected, and may be, for example, a cylindrical shape, a polygonal prism including a triangular prism, a rectangular parallelepiped, a cube, etc.

[0030] The metal base 11 is a disk-shaped metal member in plan view. The metal base 11 is made of, for example, an aluminum alloy. The metal base 11 supports the electrostatic chuck plate 10 from the back surface 2b side. The metal base 11 is supported from below by a cylindrical support member 3 that extends downward from the outer peripheral portion of the back surface of the metal base 11. A cylindrical side cover 4 that surrounds these is disposed on the radially outer side of the electrostatic chuck plate 10, the metal base 11, and the support member 3.

[0031] The metal base 11 has a heater element 9 stretched inside. The heater element 9 and the metal base 11 are insulated from each other. A heater power supply device (not shown) is connected to the heater element 9. The heater element 9 may be provided outside the metal base 11. The heater element 9 may be disposed inside the electrostatic chuck plate 10. The heater element 9 may be disposed between the electrostatic chuck plate 10 and the metal base 11.

[0032] The metal base 11 has two power supply terminals 13a and 13b. As shown in FIG. 1, the power supply terminal 13a is installed in a terminal installation hole 11a of the metal base 11. The power supply terminal 13b is installed in a terminal installation hole 11b. The terminal installation holes 11a and 11b are through holes penetrating the metal base 11 in the vertical direction.

[0033] The power supply terminal 13a includes a cylindrical insulating tube 14 fixed to the upper end portion of the inner wall of the terminal installation hole 11a, a plunger 15 installed in the insulating tube 14 so as to be vertically movable, a coil spring 16 applying an upward elastic force to the plunger 15, and a receiving plate 17 closing the lower opening of the insulating tube 14 and supporting the coil spring 16 from below. The power supply terminal 13b has the same configuration as the power supply terminal 13a.

[0034] The insulating tube 14 has a length substantially the same as the thickness of the metal base 11. The insulating tube 14 insulates between the conductive components of the power supply terminals 13a and 13b and the metal base 11. The insulating tube 14 is made of, for example, alumina or the like. The plunger 15 is a rod-shaped conductive terminal extending in the vertical direction. The plunger 15 is made of, for example, tungsten, stainless steel, nickel, or the like. The plunger 15 has a disc-shaped flange extending in the horizontal direction. The coil spring 16 is a metal spring body. The coil spring 16 is made of, for example, stainless steel, inconel, or the like. The plunger 15 is inserted from the upper end portion of the coil spring 16. The upper end of the coil spring 16 contacts the lower surface of the flange of the plunger 15. The receiving plate 17 is a circular metal plate. The receiving plate 17 is made of, for example, Kovar, tungsten, etc. The receiving plate 17 is fixed to the insulating tube 14. The coil spring 16 is sandwiched vertically between the flange of the plunger 15 and the receiving plate 17.

[0035] The plungers 15 of the power supply terminals 13a and 13b each have their upper ends protruding upward from the upper surface of the metal base 11. When the electrostatic chuck plate 10 is placed on the upper surface of the metal base 11, the upper ends of the plungers 15 are pushed downward by the back surface 2b of the electrostatic chuck plate 10. Since the plunger 15 is pushed upward by the coil spring 16, the contact state between the plunger 15 and the electrostatic chuck plate 10 is maintained.

[0036] The electrostatic chuck plate 10 has electrode terminals 64 at the contact positions with the two plungers 15 respectively. The electrode terminals 64 extend downward from the lower surfaces of the two second electrode portions 62 respectively and are exposed on the back surface 2b of the dielectric substrate 2. When the plunger 15 and the electrode terminal 64 are in contact, the power supply terminal 13a is electrically connected to one of the second electrode portions 62, and the power supply terminal 13b is electrically connected to the other second electrode portion 62.

[0037] The power supply terminals 13a and 13b are connected to the power supply device 110 on the receiving plate 17. Therefore, the power supply device 110 and the second electrode portion 62 (adsorption electrode 6) are electrically connected via the power supply terminals 13a and 13b.

[0038] As shown in FIG. 1, the power supply device 110 includes a high-frequency power supply 111 for plasma excitation, a matcher 112, a DC power supply 113 for electrostatic adsorption, and a plurality of resistors 114 to 118.

[0039] The high-frequency power supply 111 for plasma excitation is electrically connected to the main power supply rod 8 that extends downward from the lower surface of the metal base 11 via the matcher 112. The main power supply rod 8 is a rod-shaped member made of metal, such as aluminum, copper, or stainless steel. The upper end of the main power supply rod 8 is fixed to the lower surface of the metal base 11. The high-frequency power output from the high-frequency power supply 111 is supplied to the metal base 11 via the main power supply rod 8.

[0040] The DC power supply 113 for electrostatic adsorption is connected to the receiving plate 17 of the power supply terminal 13a via the resistor 114. The DC power supply 113 is connected to the receiving plate 17 of the power supply terminal 13b via the resistor 115. The voltage of the DC power supply 113 is applied to the two second electrode portions 62 via the power supply terminals 13a and 13b. The voltage of the DC power supply 113 is also applied to the first electrode portion 61 connected to the second electrode portion 62 via the connection pin 63.

[0041] In the case of this embodiment, the negative terminal of the DC power supply 113 is connected to the output terminal of the matcher 112 via the resistor 116. Also, the positive terminal of the DC power supply 113 is connected to the output terminal of the matcher 112 via the resistor 117. Further, the output terminal of the matcher 112 is connected to the ground via the resistor 118. With this configuration, positive and negative poles can be formed with respect to the bipolar adsorption electrode 6 based on the ground reference.

[0042] The metal base 11 has a through hole 11c that penetrates the metal base 11 in the vertical direction. A gas supply pipe 18 is connected to the lower opening of the through hole 11c. The end of the gas supply pipe 18 on the side opposite to the through hole 11c is connected to a gas supply source (not shown). The gas supply pipe 18 is a pipe made of an insulating material such as alumina.

[0043] The upper opening of the through hole 11c opens into the space between the dielectric substrate 2 and the metal base 11. In the case of this embodiment, the through hole 11c is disposed at a position overlapping with the gas hole 2e of the dielectric substrate 2 in a plan view. In the plan view, the positions of the through hole 11c and the gas hole 2e may be offset from each other. The space inside the through hole 11c is connected to the space between the dielectric substrate 2 and the metal base 11, and further connected to the space between the mounting surface 2a and the wafer W through the gas hole 2e. The cooling gas supplied from the gas supply source through the gas supply pipe 18 is supplied to the spaces on the upper and lower surfaces of the dielectric substrate 2 through the through hole 11c and the gas hole 2e.

[0044] The support member 3 is cylindrical and extends from the outer peripheral end of the lower surface of the metal base 11 toward the bottom wall 102. The support member 3 is a member made of an insulating material such as alumina. The lower end portion of the support member 3 is fixed to the upper surface of the bottom wall 102. The support member 3 is disposed along the periphery of the opening 102a of the bottom wall 102. The space between the support member 3 and the bottom wall 102 is hermetically sealed by, for example, an O-ring or the like.

[0045] The space inside the support member 3 is connected to the space outside the vacuum vessel 101 through the opening 102a of 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 of the bottom wall 102.

[0046] The side cover 4 is a cylindrical member extending in the vertical direction. The side cover 4 is put on the outside of the support member 3. In the case of this embodiment, the side cover 4 is radially opposed to the side end surface 2c of the dielectric substrate 2 and the outer peripheral surface 3b of the support member 3. 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, alumina, quartz, or the like. The material of the side cover 4 is not particularly limited as long as it has the required plasma resistance. The electrostatic chuck device 1 may also be configured not to include the side cover 4.

[0047] The upper end portion 4a of the side cover 4 is positioned laterally of the dielectric substrate 2. The side cover 4 has a notch 4b extending along the inner periphery at a corner on the inner peripheral side of the upper end portion 4a. The outer peripheral portion of the focus ring 5 is disposed inside the notch 4b. The height position (the position in the vertical direction shown in the figure) of the upper end face 4c of the side cover 4 substantially coincides with the height position of the upper surface of the focus ring 5 and the height position of the upper surface of the wafer W.

[0048] In the electrostatic chuck device 1 having the above configuration, by applying a DC voltage from the DC power supply 113 of the power supply device 110 to the bipolar adsorption electrode 6, an electrostatic force is generated between the wafer W, the focus ring 5, the metal base 11, and the adsorption electrode 6. Thereby, the wafer W is adsorbed on the placement surface 2a of the electrostatic chuck plate 10, and the focus ring 5 is adsorbed in the ring adsorption region 2d. Further, the back surface 2b of the electrostatic chuck plate 10 is adsorbed on the upper surface of the metal base 11.

[0049] That is, the electrostatic chuck plate 10 of the present embodiment is a double-sided adsorption type electrostatic chuck plate that adsorbs both the wafer W and the metal base 11. The electrostatic chuck plate 10 has a ring adsorption region 2d where the focus ring 5 is adsorbed on the same side as the placement surface 2a, and a base adsorption region 2f where the electrostatic chuck plate 10 is adsorbed to the metal base 11 on the back surface 2b opposite to the placement surface 2a. According to this configuration, by setting the state where no voltage is applied to the adsorption electrode 6, the electrostatic chuck plate 10 can be maintained in a state movable with respect to the metal base 11. Thereby, in the present embodiment, during the plasma treatment of the wafer W, until the wafer W reaches the processing temperature, the electrostatic chuck plate 10 is not adsorbed to the metal base 11, and after the wafer W reaches the processing temperature, the electrostatic chuck plate 10 is adsorbed, and the plasma treatment can be performed. According to the above-described plasma processing method, even if the electrostatic chuck plate 10 and the metal base 11 expand as the temperature rises, since the electrostatic chuck plate 10 is movable on the metal base 11, no stress is applied to the contact portion between the electrostatic chuck plate 10 and the metal base 11. Therefore, according to the present embodiment, excellent reliability can be obtained in the high-temperature treatment of the wafer W.

[0050] Also, in the present embodiment, since the focus ring 5 is placed on the electrostatic chuck plate 10, in the non-adsorbed state, the focus ring 5 moves together with the electrostatic chuck plate 10 with respect to the metal base 11. Therefore, even if the electrostatic chuck plate 10 moves with respect to the metal base 11, the positional relationship between the focus ring 5 and the wafer W is less likely to change. By arranging the wafer W and the focus ring 5 at appropriate positions, the deviation of the plasma at the outer peripheral portion of the wafer W can be suppressed.

[0051] In the present embodiment, the electrostatic chuck plate 10 has a step between the mounting surface 2a and the ring adsorption region 2d. The surface of the ring adsorption region 2d facing the focus ring 5 is located closer to the metal base 11 than the mounting surface 2a. According to this configuration, when using a focus ring 5 thicker than the wafer W, it becomes easier to eliminate the step between the upper surface of the wafer W and the upper surface of the focus ring 5, and the deviation of the plasma at the outer peripheral portion of the wafer W can be suppressed. Also, due to the above-described step, it becomes difficult for the focus ring 5 to move in the planar direction. Even when the electrostatic chuck plate 10 moves with respect to the metal base 11, it becomes easier to maintain the appropriate positional relationship between the focus ring 5 and the wafer W. When the focus ring 5 can be held by the step of the electrostatic chuck plate 10, the electrostatic chuck plate 10 may be configured not to have the adsorption electrode 6 in the ring adsorption region 2d.

[0052] In this embodiment, the adsorption electrode 6 includes a first electrode portion 61 located in the surface layer portion on the mounting surface 2a side of the dielectric substrate 2, a second electrode portion 62 located in the surface layer portion on the metal base 11 side of the dielectric substrate 2, and a connection pin 63 that connects the first electrode portion 61 and the second electrode portion 62 inside the dielectric substrate 2. According to this configuration, since the first electrode portion 61 can be disposed near the mounting surface 2a and the second electrode portion 62 can be disposed near the back surface 2b, the adsorption force to the wafer W and the metal base 11 can be increased. On the other hand, when the adsorption electrode 6 has a two-layer structure, there is a disadvantage that the dielectric substrate 2 becomes thick and the capacitance of the electrostatic chuck plate 10 becomes small, making it difficult to excite plasma. In this regard, in this embodiment, since the first electrode portion 61 and the second electrode portion 62 are electrically connected by the connection pin 63, the portion of the dielectric substrate 2 located between the first electrode portion 61 and the second electrode portion 62 does not affect the capacitance. Therefore, according to the electrostatic chuck plate 10 of this embodiment, a capacitance equivalent to that in the case where the adsorption electrode 6 has a single-layer structure can be obtained, and plasma can be easily excited.

[0053] The electrostatic chuck device 1 of this embodiment has a plurality of protrusions 22 distributed in the plane direction of the electrostatic chuck plate 10 in the base adsorption region 2f of the electrostatic chuck plate 10. According to this configuration, since the cooling gas can also be circulated on the back surface 2b of the electrostatic chuck plate 10, the heat uniformity of the electrostatic chuck plate 10 can be improved.

[0054] In this embodiment, the electrostatic chuck plate 10 is configured to have the protrusions 22, but the upper surface of the metal base 11 (the surface facing the base adsorption region 2f) may be configured to have protrusions equivalent to the protrusions 22. Also in this case, the cooling gas can be circulated between the electrostatic chuck plate 10 and the metal base 11, and the heat uniformity of the electrostatic chuck plate 10 and the wafer W can be improved.

[0055] In addition, in this embodiment, the electrostatic chuck plate 10 is configured to be freely adsorbed to and detached from the metal base 11, but a part of the back surface 2b of the electrostatic chuck plate 10 may be fixed to the metal base 11. For example, the electrostatic chuck plate 10 may have a base fixing portion fixed to the upper surface of the metal base 11 at the central portion in a plan view of the back surface 2b. As the fixing method, adhesion, screwing, etc. can be used. The position of the base fixing portion may be other than the central portion of the back surface 2b, or may be provided at a plurality of locations on the back surface 2b.

[0056] Furthermore, a fitting structure for preventing displacement may be provided between the electrostatic chuck plate 10 and the metal base 11. For example, the electrostatic chuck plate 10 may be provided with a recess recessed upward from the back surface 2b, and the metal base 11 may be provided with a protrusion fitted into the recess. In the fitting structure, the side surfaces of the recess and the protrusion may be tapered surfaces respectively. According to this configuration, when the electrostatic chuck plate 10 is placed on the metal base 11, the electrostatic chuck plate 10 is easily guided to a predetermined position, and displacement from the metal base 11 is less likely to occur. Also, in the fitting structure, the recess of the electrostatic chuck plate 10 and the protrusion of the metal base 11 may be adhered to serve as a base fixing portion. In the fitting structure, the positions of the recess and the protrusion may be interchanged. That is, a recess recessed downward may be provided on the upper surface of the metal base 11, and the electrostatic chuck plate 10 may be provided with a protrusion fitted into the recess of the metal base material 11.

[0057] In the case of the configuration having the above-described base fixing portion, among the back surface 2b of the electrostatic chuck plate 10, the region other than the fixing portion is a base adsorption region that can be adsorbed to the metal base 11. Even in such a configuration, when heating the wafer W, by setting the electrostatic chuck plate 10 in a non-adsorbed state, at least the base adsorption region of the back surface 2b can move relative to the metal base 11, so that the stress acting between the electrostatic chuck plate 10 and the metal base 11 can be reduced. When the base fixing portion is located at the central portion of the back surface 2b, since the base adsorption region surrounds the base fixing portion, the stress reduction effect can be easily obtained.

[0058] Also, in the present embodiment, the case where the electrode for adsorbing the focus ring 5 is the second electrode portion 62 has been described, but other configurations may be adopted. For example, the adsorption electrode 6 may have a configuration in which it is located on the outer peripheral side of the first electrode portion 61 and is a third electrode portion located in the surface layer portion of the ring adsorption region 2d. The third electrode portion may be configured to be electrically connected to at least one of the first electrode portion 61 and the second electrode portion 62, or may be configured to be connected to a power source of a different system from the first electrode portion 61 and the second electrode portion 62. According to this configuration, since the third electrode portion can be arranged closer to the surface layer portion of the ring adsorption region 2d than the second electrode portion 62, the adsorption force for the focus ring 5 can be increased. Note that the first electrode portion 61 may be extended to the ring adsorption region 2d to form the third electrode portion. In this case, the first electrode portion 61 is bent along the step between the placement surface 2a and the ring adsorption region 2d.

[0059] (Modification example) A modification example of the first embodiment will be described with reference to FIGS. 3A and 3B. FIG. 3A is a partial cross-sectional view of the outer peripheral portion of the electrostatic chuck plate 10 of the modification example. FIG. 3B is a partial cross-sectional view showing a state in which the focus ring 5 is worn out in the electrostatic chuck plate 10 of the first embodiment.

[0060] As shown in FIG. 3B, when the focus ring 5 is worn and thinned, the capacitance of the focus ring 5 becomes relatively large, so that the electron density of the plasma P on the focus ring 5 increases with respect to the wafer W. Compared with the case where the non-worn focus ring 5 is used, the distribution of the plasma becomes non-uniform, and processing unevenness is likely to occur in the outer peripheral portion of the wafer W.

[0061] Therefore, when the focus ring 5 is worn, by replacing it with the electrostatic chuck plate 10 of the modified example shown in FIG. 3A, it becomes easier to maintain the plasma distribution. In the case of the configuration shown in FIG. 3A, in the electrostatic chuck plate 10 of the modified example, the protrusion 22A provided on the back surface 2b of the region overlapping the ring adsorption region 2d has a larger diameter than the protrusion 22 provided in the region overlapping the mounting surface 2a. According to this configuration, since the ratio of the dielectric in the ring adsorption region 2d of the electrostatic chuck plate 10 can be increased, even when the worn focus ring 5 is used, the overall capacitance change can be reduced. Thereby, it is possible to suppress the occurrence of non-uniformity in the plasma.

[0062] The protrusion 22A in the region overlapping the ring adsorption region 2d may have a configuration other than the large-diameter protrusion shown in FIG. 3A. For example, a configuration in which the arrangement density of the protrusions 22A is made larger than the arrangement density of the protrusions 22 may be used. More specifically, for the protrusions 22A in the region overlapping the ring adsorption region 2d, the diameter may be the same as the diameter of the protrusions 22 in the region overlapping the mounting surface 2a, while the arrangement density of the protrusions 22A is made larger than the arrangement density of the protrusions 22.

[0063] Furthermore, depending on the configuration of the focus ring 5, the diameter of the protrusion 22A in the region overlapping the ring adsorption region 2d may be made smaller than the diameter of the protrusion 22 in the region overlapping the mounting surface 2a. Alternatively, the arrangement density of the protrusions 22A in the region overlapping the ring adsorption region 2d may be made smaller than the arrangement density of the protrusions 22 in the region overlapping the mounting surface 2a. By adopting such a configuration, a focus ring 5 having a large thickness can be used.

[0064] In the electrostatic chuck plate 10 of the modified example described above, the distribution density of the plurality of protrusions 22 is different between the region that overlaps with the placement surface 2a in a plan view within the base adsorption region 2f and the region that overlaps with the ring adsorption region 2d in a plan view within the base adsorption region 2f. According to this configuration, by changing the electrostatic chuck plate 10 according to the thickness of the focus ring 5, it is possible to suppress the non-uniformity of the plasma distribution in the outer peripheral portion of the wafer W. The processing unevenness in the outer peripheral portion of the wafer W can be reduced.

[0065] In addition, in the modified example, the electrostatic chuck plate 10 has the protrusions 22 and 22A, but a configuration in which the upper surface of the metal base 11 (the surface facing the base adsorption region 2f) has protrusions equivalent to the protrusions 22 and 22A may also be used.

[0066] (Second Embodiment) FIG. 4 is a cross-sectional view of a plasma processing apparatus including the electrostatic chuck apparatus 201 of the second embodiment. In FIG. 4, the components denoted by the same reference numerals as those in FIGS. 1 to 3 are the components common to the electrostatic chuck apparatus 1 of the first embodiment.

[0067] The electrostatic chuck apparatus 201 of the second embodiment includes an electrostatic chuck plate 210 having a monopolar adsorption electrode 206, a focus ring 5 disposed on the outer peripheral portion of the electrostatic chuck plate 210, a metal base 11 that supports the electrostatic chuck plate 210 from below, a support member 3 that supports the metal base 11, and a side cover 4 located radially outside the support member 3.

[0068] The adsorption electrode 206 includes a first electrode portion 261 located in the surface layer portion on the placement surface 2a side of the dielectric substrate 2, a second electrode portion 262 located in the surface layer portion on the metal base 11 side of the dielectric substrate 2, and a plurality of connection pins 263 that connect the first electrode portion 261 and the second electrode portion 262 inside the dielectric substrate 2.

[0069] Both the first electrode portion 261 and the second electrode portion 262 of this embodiment are circular in plan view. The diameter of the second electrode portion 262 is larger than the diameter of the first electrode portion 261. The first electrode portion 261 is disposed in a region that overlaps with the placement surface 2a of the dielectric substrate 2 in plan view. The second electrode portion 262 extends radially outward beyond the outer peripheral end of the first electrode portion 261. The outer peripheral portion of the second electrode portion 262 overlaps with the ring adsorption region 2d in plan view.

[0070] The connection pins 263 are arranged at a plurality of locations within the region where the first electrode portion 261 and the second electrode portion 262 overlap in plan view. The number and arrangement of the connection pins 263 are the same as those of the connection pins 63 in the first embodiment shown in FIG. 2. The number and arrangement of the connection pins 263 can be appropriately changed according to the planar area of the adsorption electrode 206, the type (DC or AC) and magnitude of the current flowing through the adsorption electrode 206, etc.

[0071] The electrostatic chuck plate 210 has an electrode terminal 264 that extends downward from the lower surface of the second electrode portion 262. The lower end of the electrode terminal 264 is exposed on the back surface 2b of the dielectric substrate 2. In the case of this embodiment, since the adsorption electrode 206 is a unipolar type, only the power supply terminal 13a of the metal base 11 is connected to the adsorption electrode 206. The upper end of the plunger 15 of the power supply terminal 13a contacts the electrode terminal 264 of the electrostatic chuck plate 210. A DC power supply 113 for electrostatic adsorption is connected to the power supply terminal 13a via a resistor 114. In the case of this embodiment, the adsorption electrode 206 is connected to the positive terminal of the DC power supply 113.

[0072] The electrostatic chuck plate 210 has a plurality of through holes 23 that penetrate the dielectric substrate 2 in the ring adsorption region 2d, and a groove 24 that opens on the upper surface of the ring adsorption region 2d. The groove 24 is annular and extends along the ring adsorption region 2d in plan view. The width of the groove 24 is smaller than the width of the focus ring 5. The upper opening of the groove 24 is blocked by the focus ring 5 adsorbed to the ring adsorption region 2d.

[0073] The through-hole 23 opens to the bottom surface of the groove 24 and the back surface 2b of the dielectric substrate 2. Therefore, the groove 24 is connected to the gap 25 between the back surface 2b of the dielectric substrate 2 and the metal base 11 through the through-hole 23. The cooling gas supplied to the gap 25 through the gas supply pipe 18 and the through-hole 11c of the metal base 11 flows into the groove 24 through the through-hole 23. The configuration having the groove 24 promotes the cooling of the focus ring 5.

[0074] A power supply device 220 is connected to the main power supply rod 8 extending downward from the lower surface of the metal base 11. The power supply device 220 includes a high-frequency power supply 111 for plasma excitation, a matcher 112, a DC power supply 121 for applying a bias voltage, and a resistor 122. The high-frequency power supply 111 is connected to the main power supply rod 8 through the matcher 112. The DC power supply 121 is connected to the main power supply rod 8 through the resistor 122.

[0075] In the electrostatic chuck device 201 of the second embodiment having the above configuration, by applying a voltage from the DC power supply 113 to the adsorption electrode 6, the wafer W can be adsorbed on the placement surface 2a of the electrostatic chuck plate 210, and the back surface 2b of the electrostatic chuck plate 210 can be adsorbed on the upper surface of the metal base 11.

[0076] Also in the electrostatic chuck device 201 of the second embodiment, by providing the double-sided adsorption type electrostatic chuck plate 210, when heating the wafer W, the electrostatic chuck plate 210 can be set in a non-adsorbed state and made movable on the metal base 11. Thereby, similar to the first embodiment, breakage of the electrostatic chuck device 201 due to thermal stress can be prevented. Therefore, according to the electrostatic chuck device 201 of the second embodiment, high-temperature processing of the wafer W is possible.

[0077] The electrostatic chuck plate 210 of the second embodiment has a two-layer adsorption electrode 206. Since the first electrode portion 261 and the second electrode portion 262 are respectively arranged near the object to be adsorbed, a high adsorption force can be obtained.

[0078] Also in this embodiment, since the first electrode portion 261 and the second electrode portion 262 are connected via the connection pin 263, even when a relatively thick dielectric substrate 2 is used, the substantial capacitance of the electrostatic chuck plate 210 does not increase. Therefore, in the electrostatic chuck device 201 of this embodiment, plasma can be easily excited by power input from the high-frequency power supply 111 to the metal base 11.

[0079] Note that the electrostatic chuck device 201 of the second embodiment can appropriately combine the configurations of the first embodiment, the modified example, and the third embodiment described in this specification within a range that does not cause contradictions.

[0080] (Third Embodiment) FIG. 5 is a cross-sectional view of a plasma processing apparatus including the electrostatic chuck device 301 of the third embodiment. In FIG. 5, the components denoted by the same reference numerals as those in FIGS. 1 to 4 are the same components as those of the electrostatic chuck device 1 of the first embodiment or the electrostatic chuck device 201 of the second embodiment.

[0081] The electrostatic chuck device 301 of the third embodiment includes an electrostatic chuck plate 310 having a monopolar adsorption electrode 306, a focus ring 5 disposed on the outer peripheral portion of the electrostatic chuck plate 310, a metal base 11 that supports the electrostatic chuck plate 310 from below, a support member 3 that supports the metal base 11, and a side cover 4 located radially outside the support member 3.

[0082] The adsorption electrode 306 has a first electrode portion 361 located in the surface layer portion on the mounting surface 2a side of the dielectric substrate 2 and a second electrode portion 362 located in the surface layer portion on the metal base 11 side of the dielectric substrate 2. The first electrode portion 361 and the second electrode portion 362 of this embodiment are both circular in plan view. The diameter of the second electrode portion 362 is larger than the diameter of the first electrode portion 361. The first electrode portion 361 is disposed in a region that overlaps the mounting surface 2a of the dielectric substrate 2 in plan view. The second electrode portion 362 extends radially outward from the outer peripheral end of the first electrode portion 361. The outer peripheral portion of the second electrode portion 362 overlaps the ring adsorption region 2d in plan view.

[0083] The electrostatic chuck plate 310 has an electrode terminal 364a extending downward from the lower surface of the first electrode portion 361 and an electrode terminal 364b extending downward from the lower surface of the second electrode portion 362. The lower ends of the electrode terminals 364a and 364b are respectively exposed on the back surface 2b of the dielectric substrate 2. The electrode terminal 364a contacts the plunger 15 of the power supply terminal 13a protruding from the upper surface of the metal base 11. The electrode terminal 364b contacts the plunger 15 of the power supply terminal 13b protruding from the upper surface of the metal base 11.

[0084] A DC power supply 123 for electrostatic adsorption is connected to the power supply terminal 13a via a resistor 124. In the case of this embodiment, the power supply terminal 13a is electrically connected to the positive terminal of the DC power supply 123. A DC power supply 125 for electrostatic adsorption is connected to the power supply terminal 13b via a resistor 126. In the case of this embodiment, the power supply terminal 13b is electrically connected to the positive terminal of the DC power supply 125.

[0085] A power supply device 320 is connected to the main power supply rod 8 extending downward from the lower surface of the metal base 11. The power supply device 320 includes a high-frequency power supply 111 for plasma excitation, a matcher 112, a DC power supply 121 for applying a bias voltage, and a resistor 122. The high-frequency power supply 111 is connected to the main power supply rod 8 via the matcher 112. The DC power supply 121 is connected to the main power supply rod 8 via the resistor 122.

[0086] In the electrostatic chuck device 201 of the third embodiment having the above configuration, by applying a voltage from the DC power supply 123 to the first electrode portion 361, the wafer W can be adsorbed on the mounting surface 2a of the electrostatic chuck plate 310. Also, by applying a voltage from the DC power supply 125 to the second electrode portion 362, the back surface 2b of the electrostatic chuck plate 310 can be adsorbed on the upper surface of the metal base 11.

[0087] Also in the electrostatic chuck device 301 according to the third embodiment, by providing the double-sided adsorption type electrostatic chuck plate 310, when heating the wafer W, the electrostatic chuck plate 310 can be set in a non-adsorbed state and made movable on the metal base 11. Thus, similar to the first embodiment, breakage of the electrostatic chuck device 301 due to thermal stress can be prevented. Therefore, according to the electrostatic chuck device 301 of the third embodiment, high-temperature processing of the wafer W is possible.

[0088] The electrostatic chuck plate 310 of the third embodiment has an adsorption electrode 306 having a two-layer structure. Since the first electrode portion 361 and the second electrode portion 362 are respectively arranged near the object to be adsorbed, a high adsorption force can be obtained.

[0089] In the present embodiment, the first electrode portion 361 and the second electrode portion 362 are connected to different DC power supplies 123 and 125, respectively. According to this configuration, it becomes easy to adjust the potential of the first electrode portion 361 for adsorbing the wafer W and the potential of the second electrode portion 362 for adsorbing the metal base 11 and the focus ring 5 to appropriate potentials. It becomes difficult to cause adsorption failure and heating failure, and the yield of plasma processing can be improved.

[0090] Note that in the electrostatic chuck device 301 of the third embodiment, within a range that does not cause contradictions, the configurations of the first embodiment, the modified example, and the second embodiment described in this specification can be appropriately combined.

Industrial Applicability

[0091] The present invention can provide a wafer support device and an electrostatic chuck device having excellent reliability during high-temperature use. The present invention can provide an electrostatic chuck plate capable of double-sided chucking.

Explanation of Signs

[0092] 1, 201, 301... Electrostatic chuck device 2... Dielectric substrate 2a... Mounting surface 2b... Back surface 2c... Side end surface 2d… Ring adsorption region 2e… Gas hole 2f… Base adsorption region 3… Cylindrical support member 3b… Outer peripheral surface 4… Side cover 4a… Upper end 4b… Notch 4c… Upper end face 5… Focus ring 6,206,306… Adsorption electrode 8… Main power supply rod 9… Heater element 10,210,310… Electrostatic chuck plate 11… Metal base 11a, 11b… Terminal installation holes 11c… Through hole 13a, 13b… Power supply terminals 14… Insulating tube 15… Plunger 16… Coil spring 17… Plate 18… Gas supply pipe 21,22,22A… Protrusion 23… Through hole 24… Groove 25… Gap 61,261,361… First electrode part 62,262,362… Second electrode part 63,263… Connection pin 64, 264, 364, 364a, 364b… Electrode terminal 100… Plasma processing apparatus 101… Vacuum chamber 102… Bottom wall 102a… Opening 102b… Exhaust port 103… Cylindrical side wall 104… Top wall 110… Power supply device 111… High-frequency power supply 112… Matching unit 113… DC power supply 114, 115, 116, 117, 118, 122, 124, 126… Resistor 121, 123, 125… DC power supply 210... Electrostatic chuck plate 220... Power supply device P... Plasma W... Wafer

Claims

1. An electrostatic chuck plate having a mounting surface on which a wafer is placed, and a suction electrode located inside the dielectric substrate, and a metal base that supports the electrostatic chuck plate from the back side opposite to the mounting surface, and a focus ring installed on the outer peripheral portion of the electrostatic chuck plate and surrounding the mounting surface. An electrostatic chuck device comprising: The electrostatic chuck plate has a ring adsorption region adsorbed to the focus ring on the surface on the same side as the mounting surface, and a base adsorption region adsorbed to the metal base on the back surface on the side opposite to the mounting surface. One or both of the base adsorption region of the electrostatic chuck plate and the surface of the metal base facing the base adsorption region have a plurality of protrusions distributed in the plane direction of the electrostatic chuck plate. The electrostatic chuck device, wherein the distribution density of the plurality of protrusions is different between a region overlapping with the mounting surface in plan view and a region overlapping with the ring adsorption region in the base adsorption region.

2. The suction electrode has a first electrode portion located in the surface layer portion on the mounting surface side of the dielectric substrate, a second electrode portion located in the surface layer portion on the metal base side of the dielectric substrate, and a connection pin connecting the first electrode portion and the second electrode portion inside the dielectric substrate. The electrostatic chuck device according to claim 1.

3. The suction electrode has a third electrode portion located on the outer peripheral side of the first electrode portion and in the surface layer portion of the ring adsorption region. The electrostatic chuck device according to claim 2.

4. The electrostatic chuck plate has a step between the mounting surface and the ring adsorption region, and the surface of the ring adsorption region facing the focus ring is closer to the metal base than the mounting surface. The electrostatic chuck device according to any one of claims 1 to 3.

5. The electrostatic chuck plate has a base fixing portion fixed to the metal base at the center of the back surface in plan view, and the base adsorption region is disposed surrounding the base fixing portion. The electrostatic chuck device according to any one of claims 1 to 4.

6. Among the base adsorption regions, the diameter of the protrusions in the region overlapping with the ring adsorption region in plan view is larger than the diameter of the protrusions in the region overlapping with the mounting surface in plan view. The electrostatic chuck device according to claim 1.

7. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Among the base adsorption regions, the arrangement density of the protrusions in the region that overlaps with the ring adsorption region in a plan view is greater than the arrangement density of the protrusions in the region that overlaps with the placement surface in a plan view. The electrostatic chuck device according to claim 1.

8. Among the base adsorption regions, the diameter of the protrusions in the region that overlaps with the ring adsorption region in a plan view is smaller than the diameter of the protrusions in the region that overlaps with the placement surface in a plan view. The electrostatic chuck device according to claim 1.

9. Among the base adsorption regions, the arrangement density of the protrusions in the region that overlaps with the ring adsorption region in a plan view is smaller than the arrangement density of the protrusions in the region that overlaps with the placement surface in a plan view. The electrostatic chuck device according to claim 1.

10. Both the base adsorption region of the electrostatic chuck plate and the surface of the metal base that faces the base adsorption region have a plurality of protrusions distributed in the plane direction of the electrostatic chuck plate. The electrostatic chuck device according to any one of claims 1 to 9.

11. An electrostatic chuck plate having a placement surface on which a wafer is placed, and an adsorption electrode located inside the dielectric substrate; A metal base that supports the electrostatic chuck plate from the back side opposite to the placement surface; A focus ring installed at the outer peripheral portion of the electrostatic chuck plate and surrounding the placement surface; An electrostatic chuck device comprising: The electrostatic chuck plate has a ring adsorption region that is adsorbed to the focus ring on the surface on the same side as the placement surface, and a base adsorption region that is adsorbed to the metal base on the back surface on the opposite side of the placement surface. The electrostatic chuck plate has a base fixing portion fixed to the metal base at the central portion of the back surface in a plan view. The base adsorption region is arranged to surround the base fixing portion. The electrostatic chuck device.

12. Either one or both of the base adsorption region of the electrostatic chuck plate and the surface of the metal base that faces the base adsorption region have a plurality of protrusions distributed in the plane direction of the electrostatic chuck plate. The electrostatic chuck device according to claim 11.

13. Both the base adsorption region of the electrostatic chuck plate and the surface of the metal base that faces the base adsorption region have a plurality of protrusions distributed in the plane direction of the electrostatic chuck plate. The electrostatic chuck device according to claim 12.

14. The adsorption electrode is A first electrode portion located in the surface layer portion on the mounting surface side of the dielectric substrate; A second electrode portion located in the surface layer portion on the metal base side of the dielectric substrate; A connection pin that connects the first electrode portion and the second electrode portion inside the dielectric substrate; having The electrostatic chuck device according to any one of claims 11 to 13.

15. The adsorption electrode has a third electrode portion located on the outer peripheral side of the first electrode portion and located in the surface layer portion of the ring adsorption region. The electrostatic chuck device according to claim 14.

16. The electrostatic chuck plate has a step between the mounting surface and the ring adsorption region. The surface of the ring adsorption region facing the focus ring is closer to the metal base than the mounting surface. The electrostatic chuck device according to any one of claims 11 to 15.

17. An electrostatic chuck plate having a dielectric substrate having a mounting surface on which a wafer is mounted and an adsorption electrode located inside the dielectric substrate; A metal base that supports the electrostatic chuck plate from the back side opposite to the mounting surface; A focus ring installed at the outer peripheral portion of the electrostatic chuck plate and surrounding the mounting surface; An electrostatic chuck device comprising: The electrostatic chuck plate has a ring adsorption region adsorbed to the focus ring on the surface on the same side as the mounting surface, and a base adsorption region adsorbed to the metal base on the back surface on the side opposite to the mounting surface. The adsorption electrode is A first electrode portion located in the surface layer portion on the mounting surface side of the dielectric substrate; A second electrode portion located in the surface layer portion on the metal base side of the dielectric substrate; A connection pin that connects the first electrode portion and the second electrode portion inside the dielectric substrate; having The first electrode portion is a circular electrode. The second electrode portion is a circular electrode. The planar area of the second electrode portion is larger than the planar area of the first electrode portion. The first electrode portion overlaps the mounting surface in plan view. The second electrode portion overlaps the mounting surface and the ring adsorption region in plan view.

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