Plasma Processing Equipment

Abstract

Provided is a plasma processing device which improves exhaust conductance in the inside of a vacuum container and which enables stable plasma formation. In the plasma processing device, a plurality of drive actuators are disposed on the outside of the vacuum container, and the drive actuators and the outer peripheral portion of the bottom surface of a sample stage are connected through a plurality of arms. The sample stage is driven up and down through up / down driving of the arms by the drive actuators. The arms and cables, which are connected to the sample stage for the purpose of electricity feed or the like, are disposed in parallel in the vertical direction, and the cables are set to be wiring paths along the arms, whereby sliding motion is suppressed, and the capacity occupied by a sample stage unit in the vacuum container is reduced.

Description

[Technical field]

[0001] The present disclosure relates to a plasma processing apparatus. [Background technology]

[0002] In order to improve the uniformity of plasma processing of the processing wafer, the plasma processing apparatus is required to exhaust the reaction products generated during plasma processing by a vacuum pump installed below the sample stage. On the other hand, in the plasma processing apparatus, one of the plasma processing parameters of the processing wafer is to vertically drive the height of the sample stage during processing by a driving actuator or the like in order to adjust the volume of the discharge region in which the plasma is formed, which is the space above the upper surface of the sample stage.

[0003] In recent plasma processing apparatuses, in order to improve the accuracy of wafer processing, a sample stage supporting the wafer is located in the vertical center of the processing chamber, and the processing chamber is composed of a discharge region in which plasma is generated above the top surface of the sample stage, an exhaust region facing an exhaust port located directly below the bottom surface, and a space on the outer periphery of the outer wall of the sample stage that connects and communicates between them. This technology reduces the circumferential variation of the flow of gas and particles inside the processing chamber from the space above the top surface of the sample stage where plasma is generated to the exhaust region, improving the processing accuracy.

[0004] A plasma processing apparatus having the above-described vacuum vessel structure and vertical drive mechanism is proposed, for example, in JP 2020-109847 A (Patent Document 1). Patent Document 1 discloses that "the actuator assembly 192 can be coupled to the hollow shaft 178 to move the substrate support assembly 118 in the vertical direction. The actuator assembly 192 can be disposed within the atmospheric volume 168." [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-109847 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the above-mentioned Patent Document 1, the following points are not sufficiently considered, and problems are likely to occur.

[0007] That is, the actuator assembly 192 in Patent Document 1 is installed on top of the vacuum pump 182 inside the flow module 106. For this reason, if the vacuum pump 182 and the substrate support assembly 118 equipped with the actuator assembly 192 are arranged coaxially, the volume of the vacuum vessel including the chamber body 140 including the substrate support assembly 118 and the flow module 106 will increase, the flow path through which gases and particles are exhausted by the vacuum pump 182 will expand in the vertical direction, and the conductance of the exhaust flow will deteriorate, resulting in a decrease in the processing uniformity of the substrate 116. This is not taken into consideration.

[0008] Furthermore, when applying RF power to the substrate support assembly 118, it is possible to connect the RF power supply cable to the RF power supply via the rear surface of the substrate support assembly 118, the inside of the hollow shaft 178, the atmospheric volume 168, and the through hole 170 so as to connect the chucking electrode 186 and the bias power supply 187. In this case, no consideration is given to the fact that the RF power supply cable slides when the substrate support assembly 118 is moved up and down, causing a change in impedance of the RF power supply cable, which in turn changes the impedance of the RF power supplied to the substrate support assembly 118 and causes a deterioration in uniformity of the plasma processing of the substrate 116.

[0009] An object of the present disclosure is to provide a plasma processing apparatus that improves the exhaust conductance inside a vacuum chamber and generates stable plasma. [Means for solving the problem]

[0010] In the plasma processing apparatus of the present disclosure, a plurality of drive actuators are arranged outside the vacuum chamber, and a plurality of arms connect the drive actuators to the outer periphery of the bottom surface of the sample stage. The drive actuators drive the arms up and down to drive the sample stage up and down. The arms and cables connected to the sample stage for purposes such as power supply are arranged in parallel in the vertical direction, and the cables are routed along the arms to suppress sliding, thereby reducing the volume of the vacuum chamber occupied by the sample stage unit. Effect of the Invention

[0011] According to the plasma processing apparatus, the driving actuator is arranged outside the vacuum chamber, thereby making the vacuum chamber smaller and improving the conductance. Also, by wiring the high frequency power supply cable along the outer peripheral arm arranged for the purpose of driving the sample stage up and down, the spatial distance between the sample stage and the high frequency power supply cable becomes constant, so that the plasma generation is stabilized and the yield of the plasma processing can be improved. [Brief description of the drawings]

[0012] [Figure 1] 1 is a vertical cross-sectional view illustrating a schematic configuration of a plasma processing apparatus according to an embodiment of the present disclosure. [Diagram 2] 2 is an enlarged longitudinal sectional view showing a schematic diagram of the configuration around the sample stage shown in FIG. 1. [Diagram 3] 3 is a vertical sectional view showing a schematic diagram of a state in which the sample stage shown in FIG. 2 is raised. FIG. [Figure 4] 3 is a vertical sectional view showing a schematic diagram of a state in which the sample stage shown in FIG. 2 is lowered. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, embodiments and examples of the present disclosure will be described with reference to FIGS.

[0014] (Embodiment) First, an outline of the plasma processing apparatus of the present disclosure will be described. The plasma processing apparatus (100) processes a substrate-like sample (200) such as a semiconductor wafer to be processed, which is placed on a sample stage (140) supporting the wafer (200) arranged in a processing chamber (110) inside a vacuum vessel, by using plasma formed in the processing chamber (110), in which the sample (200), the sample stage, the vacuum vessel, and an exhaust pump (170) arranged at the bottom of the vacuum vessel are arranged coaxially and symmetrically, the gas flow path has a uniform shape, and the plasma processing apparatus includes a driving mechanism (143, 142, 214, 215) for driving the sample stage (140) up and down, and the height of the sample stage (140) is arbitrarily set by the driving mechanism (143, 142, 214, 215) to process the wafer (200).

[0015] More specifically, the plasma processing apparatus (100) is disposed inside a vacuum vessel and has a processing chamber (110) inside which plasma is formed, and a sample stage (140) disposed inside the processing chamber (110) on which a semiconductor wafer (200) to be processed using plasma is placed.

[0016] The members constituting the vacuum vessel have the following configuration.

[0017] (1) Upper vessel (130): The upper vessel (130) has a cylindrical shape and is placed on the upper side of the sample stage base (141, 145) and a ring-shaped sample stage base (141, 145) connected to the sample stage (140) at the outer periphery of the sample stage (140).

[0018] (2) A plurality of support beams (206): A plurality of support beams (206) connect between the sample stage (140) and the sample stage bases (141, 145).

[0019] (3) Arm (142): The arm (142) is disposed in the space inside the support beam (206), and one end extending horizontally is connected to the bottom of the outer periphery of the sample stage (140) so as to move up and down in the space inside the support beam (206).

[0020] (4) Driving Units (143, 214, 215): The driving units (143, 214, 215) are disposed outside the vacuum vessel and connected to the other end of the arm (142) to move the arm (142) in the vertical direction.

[0021] (5) Cable (high-frequency power supply cable 210): The cable (210) is electrically connected to an electrode to which high-frequency power is supplied via a connector (211) arranged at the bottom of the sample stage (140), and is a cable through which high-frequency power flows. The cable (210) is fixed to the arm (142) and moves up and down as the arm (142) is driven.

[0022] By fixing the high frequency power supply cable (210) along the arm (142) arranged for the purpose of vertically driving the sample stage (140), the spatial distance between the sample stage (140) and the high frequency power supply cable (210) becomes constant, and the impedance of the high frequency power supply cable does not change. This makes it possible to stabilize plasma generation and improve the yield of plasma processing.

[0023] In addition, by disposing the driving unit (143, 214, 215) outside the vacuum vessel, the volume of the vacuum vessel can be prevented from increasing, and the vacuum vessel can be made relatively small. This reduces the vertical size of the flow path through which gas and particles are exhausted by the exhaust pump 170, improving the conductance of the exhaust flow. This improves the processing uniformity of the substrate 200. EXAMPLES

[0024] 1 is a vertical cross-sectional view showing a schematic configuration of a plasma processing apparatus according to an embodiment of the present invention, in particular, a schematic diagram of a main part including a vacuum vessel in a plasma processing apparatus 100 is shown.

[0025] 1 includes a vacuum chamber including an upper chamber 130 and a lower chamber 150, an exhaust pump 170 disposed below and connected thereto, and a first high frequency power supply 101 and a solenoid coil 106 disposed above. The upper chamber 130 and the lower chamber 150 each have an inner wall that has a circular horizontal cross section, and a cylindrical sample stage 140 is disposed in the center of the chamber.

[0026] The sample stage 140 is held by a second sample stage base 145. The second sample stage base 145 has a disk shape with a vertically downward recess in the center, and is fastened to at least two or more arms 142 at its outer periphery, and the arms 142 are connected to a drive actuator 143 installed outside the vacuum vessel (130, 150). The drive actuator 143 is connected to the top of a base plate 160.

[0027] The outer walls of the upper vessel 130 and the lower vessel 150 form a vacuum bulkhead. The first sample stage base 141 has a ring shape with hollow support beams 206 (see FIG. 3), and the ring portion of the ring shape is held around the upper vessel 130 and the lower vessel 150 and vacuum sealed. The first sample stage base 141 also has a path connecting the arm 142 supporting the sample stage 140 and the second sample stage base 145 and the drive actuator 143 by the multiple hollow support beams 206. The hollow support beams 206 are disposed symmetrically with respect to the vertical center of the sample stage 140 (i.e., the shape of the gas flow path with respect to the central axis of the sample stage 140 is approximately coaxially symmetric). A path is provided between the opening of the first sample stage base 141, which is connected to the hollow support beam 206, and the cylindrical cavity below the second sample stage base 145, via the hollow portion inside the hollow support beam 206 in which the arm 142 is built, and the space is kept at atmospheric pressure, and a plurality of outer circumferential bellows 146 and a central bellows 147 provide a vacuum seal between the space and the processing chamber 110 inside the vacuum vessel. Therefore, even during processing of the wafer 200, the sample stage 140 can be driven up and down by the drive actuator 143 while the inside of the vacuum vessel is maintained in a vacuum state.

[0028] Gases (processing gas, particles in the plasma, and reaction products) in the space above the sample stage 140 in the upper chamber 130 pass through the space between the hollow support beams 206 that constitute the first sample stage base 141 and are exhausted via the lower chamber 150, so that the gas flow becomes uniform in the circumferential direction of the sample stage 140 on which the wafer 200, which is the object to be processed (sample), is placed, making it possible to uniformly process the wafer 200.

[0029] Additionally, the upper vessel 130, the lower vessel 150, and the base plate 160 have flanges, and the upper vessel 130 and the lower vessel 150 are screwed to the base plate 160 at their flanges. In this embodiment, the processing chamber 110 is disposed inside the vacuum vessel, which is a cylindrical space into which a gas is introduced and an electric field and a magnetic field are supplied to form plasma. The members constituting the vessel surrounding the processing chamber 110 have a cylindrical shape on the inside, but the horizontal cross section of the outer wall may be rectangular rather than circular, or may have other shapes.

[0030] Above the processing chamber 110, a disk-shaped cover member 102 constituting a vacuum vessel, and below it, a disk-shaped shower plate 103 constituting the ceiling surface of the processing chamber 110, are disposed. The cover member 102 and the shower plate 103 are made of dielectric materials such as quartz. For this reason, these members are configured to be permeable to high-frequency electric fields such as microwaves, UHF, and VHF waves, and an electric field from a first high-frequency power source 101 disposed above passes through these members and is supplied to the inside of the processing chamber 110. In addition, a cylindrical coil (solenoid coil) 106 is disposed around the outer periphery of the outer sidewall of the vacuum vessel as a magnetic field forming means, and is configured to be able to supply the generated magnetic field to the inside of the processing chamber 110.

[0031] The shower plate 103 has a plurality of through-holes, which are process gas inlet holes, and the process gas introduced from the gas inlet ring 104 is supplied into the process chamber 110 through these inlet holes. An O-ring 107 is provided between the cover member 102 and the gas inlet ring 104. The shower plate 103 has a plurality of inlet holes arranged in an axisymmetric region about the central axis of the sample stage 140 above the sample placement surface, which is the upper surface of the sample stage 140, and a process gas having a predetermined composition and made up of different gas components is introduced into the process chamber 110 through the evenly arranged inlet holes.

[0032] The processing gas introduced into the processing chamber 110 is excited by the electromagnetic waves and magnetic field generated by the first high frequency power supply 101, which is an electric field forming means, and the solenoid coil 106, which is a magnetic field forming means, being supplied into the processing chamber 110, and is turned into plasma in a space (discharge section) above the sample stage 140 that constitutes the upper part of the processing chamber 110. The upper part of the plasma processing apparatus 100 of this embodiment constitutes a discharge block 120. The discharge block 120 has an upper part of a vacuum vessel that surrounds the region above the sample stage 140 where the processing gas is introduced and plasma is generated, and the first high frequency power supply 101 and the solenoid coil 106 arranged outside the vacuum vessel to cover the upper part of the plasma processing apparatus 100.

[0033] In particular, the discharge block 120, which is the upper part of the vacuum vessel in this embodiment, includes the cover member 102, the shower plate 103, or the gas introduction ring 104, and the discharge chamber 124, which has a cylindrical shape and is disposed above the lower ring 122, the bottom of which faces and abuts against the earth ring 125 described later, and is sandwiched between the gas introduction ring 104 and the discharge chamber 124. The space in which the plasma is generated is surrounded by the discharge chamber 124, and is a space having at least a cylindrical shape in part. A heater 121 is attached on the outer peripheral side wall of the discharge chamber 124, surrounding the outer peripheral side wall of the discharge chamber 124. Furthermore, the heater 121 receives power and a command signal from a first temperature controller 123 including a power source electrically connected to the heater 121, and adjusts the output or heat generation amount of the heater 121. With this configuration, the quartz inner cylinder 105, which is disposed inside the discharge chamber 124 with a gap provided on the inner peripheral side wall of the discharge chamber 124, can be heated. The quartz inner cylinder 105 is configured to come into contact with the plasma formed inside the quartz inner cylinder 105 .

[0034] This configuration can reduce the adhesion of reaction products to the surfaces of the members that face the plasma in the discharge part, including the quartz inner cylinder 105. Therefore, these members can be exempt from routine maintenance.

[0035] The sample stage 140 on which the wafer 200 is placed is disposed inside the processing chamber 110 so that the central axis of the sample stage 140 coincides with the central axis of the shower plate 103. The sample to be processed by the plasma is the wafer 200, which is placed on a circular mounting surface that is the upper surface of the sample stage 140, and is attracted and held by static electricity of a dielectric film that constitutes the mounting surface (electrostatic chuck). While the wafer 200 is held on the mounting surface, processing is performed on the surface of the wafer 200.

[0036] In this embodiment, the inner diameter of the cylindrical processing chamber 110, for example the diameter of the inner wall surface of the upper vessel 130, is set to 600 mm, taking into consideration that the wafer 200, which is a sample such as a semiconductor substrate, has a diameter of 300 mm. However, dimensions other than this may be used. For example, the diameter of the wafer 200 may be set to 450 mm, and the inner diameter of the processing chamber 110 may be set to 800 mm.

[0037] Furthermore, a high frequency bias power supply (second high frequency power supply) 148 is connected to an electrode arranged inside the sample stage 140, and a high frequency bias is formed above the sample stage 140 and the sample 200 placed thereon by the supplied high frequency power. An etching process proceeds on the surface of the wafer 200 by an interaction between a physical reaction caused by the high frequency bias attracting and colliding charged particles in the plasma with the surface of the sample and a chemical reaction between the radicals and the wafer surface. Furthermore, the temperature of the sample stage 140 can be controlled to a desired temperature by a second temperature controller 149.

[0038] The application of a high frequency bias to the sample stage 140 and the temperature control of the sample stage 140 are performed through a power supply wiring cord, a temperature control wiring cord, or a coolant pipe wired in a cavity formed inside the first sample stage base 141 including the hollow support beam 206, in the central bellows 147, and in a cavity formed in the second sample stage base 145 (see FIG. 3). Although not shown, in addition to the above wiring cords, wiring cords for a temperature sensor and an electrostatic chuck may also be included. The upper vessel 130 arranged around the sample stage 140 is subject to regular maintenance because reaction products tend to adhere to it.

[0039] A base plate 160 having an exhaust opening and an exhaust pump 170 are disposed below the processing chamber 110. The exhaust pump 170 is connected to the bottom of the processing chamber 110 via the exhaust opening of the base plate 160. The exhaust opening provided in the base plate 160 is disposed directly below the sample stage 140. An exhaust lid 161 having a substantially disk shape is disposed above the exhaust opening. A cylinder 162 for moving the exhaust lid 161 up and down is connected to the exhaust lid 161. By moving the exhaust lid 161 up and down by the cylinder 162, the exhaust conductance can be adjusted. The amount and speed of the gas, plasma, and product inside the processing chamber 110 that are discharged to the outside of the processing chamber 110 are adjusted by the exhaust lid 161 and the exhaust pump 170.

[0040] The exhaust lid 161 is opened when the wafer 200 is processed, and the pressure in the space inside the processing chamber 110 is maintained at a desired vacuum level by a balance between the supply of processing gas and the operation of an exhaust means such as an exhaust pump 170. In this embodiment, the pressure during processing is adjusted to a predetermined value, for example, in the range of 0.1 to 4 Pa.

[0041] In this embodiment, for example, a roughing pump such as a turbo molecular pump and a rotary pump provided in a building in which the vacuum processing apparatus is installed is used as the exhaust pump 170. Note that the exhaust section lid 161 is configured so that it can be closed during maintenance to vacuum seal the exhaust pump 170 with an O-ring.

[0042] In this embodiment, although not shown, a gate, which is an opening that communicates between the inside and outside of the vacuum chamber, is disposed on the outer wall of the upper chamber 130, and the wafer 200 is placed on the sample stage 140 through the gate by a transfer robot. During plasma processing, the opening is vacuum-sealed by a gate valve (not shown), and the vacuum seal is released only when the wafer 200 is transferred. Reference numeral 180 denotes a support for supporting the plasma processing apparatus 100.

[0043] The pressure inside the processing chamber 110 during the etching process is monitored by a vacuum gauge (not shown), and the exhaust speed is controlled by the exhaust lid 161 to thereby control the pressure inside the processing chamber 110. The supply of these processing gases and the operation of the electric field forming means (101), magnetic field forming means (106), high frequency bias (148), and exhaust means (161, 170) are adjusted by a control device (not shown) that is communicatively connected.

[0044] The processing gas used in the plasma processing is a single type of gas or a mixture of multiple types of gases at an optimal flow rate ratio for each process condition. The flow rate of this mixed gas is adjusted by a gas flow controller (not shown), and the mixed gas is introduced into the gas retention space between the shower plate 103 and the cover member 102 above the processing chamber 110 at the top of the vacuum vessel through a gas introduction ring 104 connected to the gas flow controller by a gas pipe. In this embodiment, a stainless steel gas introduction ring 104 was used.

[0045] Next, the configuration of the plasma processing apparatus according to this embodiment will be described in more detail with reference to Figures 2 to 4. Figures 2, 3 and 4 are vertical sectional views typically showing the outline of the configuration of the plasma processing apparatus according to the embodiment shown in Figure 1. Figure 2 is a vertical sectional view typically showing an enlarged configuration around the sample stage shown in Figure 1. Figure 3 is a vertical sectional view typically showing a state in which the sample stage shown in Figure 2 is raised. Figure 4 is a vertical sectional view typically showing a state in which the sample stage shown in Figure 2 is lowered.

[0046] 2 is a vertical cross-sectional view showing an enlarged lower portion of the plasma processing apparatus 100 shown in FIG. 1, and omits the first high frequency power source 101, the cover member 102, the coil 106, and other components disposed in the upper portion of the plasma processing apparatus 100. That is, the portion of the plasma processing apparatus 100 shown in FIG. 1 below the upper vessel 130 is shown in an enlarged manner. The plasma processing apparatus 100 shown in FIG. 2 is roughly divided into a vacuum vessel (130, 150), a stand (160) disposed below the vacuum vessel (130, 150) and supporting the vacuum vessel (130, 150) from below, and an exhaust means (170) connected below the stand (160) and communicating with the inside of the vacuum vessel (130, 150) to exhaust the inside. The vacuum vessel (130, 150) may include a first sample stage base 141.

[0047] In this figure, unless necessary, explanations of parts with reference numerals given in the drawing previously described in Figure 1 will be omitted. Furthermore, although not shown, a gate, which is an opening that communicates between the inside and outside of the vacuum vessel, is arranged on the outer wall of the upper vessel 130, and the wafer 200 is placed on the sample stage 140 through the gate by a transfer robot. During plasma processing, the opening is vacuum-sealed by a gate valve (not shown), and the vacuum seal is released only when the wafer 200 is transferred.

[0048] The vacuum chamber of the plasma processing apparatus 100 in Fig. 2 includes an upper chamber 130, a first sample stage base 141 below the upper chamber 130, and a lower chamber 150 below the upper chamber 130, which are stacked in layers in the vertical direction. The lower surface of the lower chamber 150 is placed on and in contact with the upper surface of a base plate 160, which serves as a stand. In other words, the lower surface of the lower chamber 150 is placed and fixed on the upper surface of the base plate 160 so that the lower surface of the lower chamber 150 and the upper surface of the base plate 160 are in contact with each other. The lower chamber 150, the first sample stage base 141, and the upper chamber 130 are placed on the base plate 160 with the inside and outside of the chamber hermetically sealed to constitute a vacuum chamber.

[0049] Furthermore, the plasma processing apparatus 100 includes, below the lower surface of the base plate 160 serving as a stand, a number of pillars 180 that support the base plate 160 and the vacuum vessel (130, 150) above the base plate 160. The upper ends of the pillars 180 are connected to the lower surface of the base plate 160, and the lower ends of the pillars 180 are connected to the upper surface of the floor of the building in which the plasma processing apparatus 100 is disposed.

[0050] The plasma processing apparatus 100 also includes an exhaust pump 170, an exhaust lid 161, and a cylinder 162. The exhaust pump 170 is disposed below a through hole, which is an exhaust port for exhausting the inside and disposed in the center of the base plate 160, in a space between the lower surface of the base plate 160 formed by supporting the base plate 160 with the support columns 180 and the floor surface of the building. The exhaust lid 161 is disposed inside the lower vessel 150 and opens or airtightly closes the exhaust port. The cylinder 162 is an actuator that drives the exhaust lid 161 up and down relative to the exhaust port.

[0051] In the plasma processing apparatus 100, the base plate 160 is also electrically connected to the ground electrode and is at ground potential, so that the lower chamber 150, the first sample stage base 141, and the upper chamber 130, which are connected to the base plate 160 with their lower surfaces in contact with each other, are also at ground potential.

[0052] The exhaust means (170) includes an exhaust pump 170 such as a turbo molecular pump arranged below and in communication with an exhaust port, which is a through hole arranged in the lower vessel 150 and the base plate 160, and an exhaust duct (not shown) that connects the inlet of the exhaust pump 170 and the exhaust port to allow them to communicate with each other. In the plasma processing apparatus 100 of Fig. 2, the exhaust port of the exhaust pump 170 is also connected to a roughing pump such as a rotary pump arranged in advance in a building in which the plasma processing apparatus 100 is installed, and the flow rate or speed of the exhaust gas discharged from the exhaust port is adjusted by increasing or decreasing the area of ​​the exhaust flow path to the exhaust port by driving the exhaust part lid 161 with a cylinder 162 to move the exhaust part lid 161 up and down relative to the exhaust port.

[0053] Fig. 3 is a vertical cross-sectional view showing an enlarged schematic configuration of a main part of the sample stage 140 on which the wafer 200 is placed, including the first sample stage base 141 shown in Fig. 2. Fig. 3 shows an enlarged view of the configuration of the sample stage 140 in more detail. The sample stage 140 is disposed in the process chamber 110 inside a vacuum vessel composed of the upper vessel 130, the first sample stage base 141, and the lower vessel 150, and holds the wafer 200 placed on the upper surface.

[0054] 3 shows the state of the apparatus during plasma processing of a wafer 200, with the sample stage 140, the second sample stage base 145, and the arm 142 raised by the driving actuator 143 in this embodiment. As in FIG. 2, the plasma processing apparatus 100 shown in FIG. 3 has a vacuum vessel (130, 150), a base plate 160 disposed below the vacuum vessel (130, 150), and an exhaust means (170) disposed below the base plate 160, which are arranged in the vertical direction. Furthermore, the vacuum vessel has an upper vessel 130, a first sample stage base 141, and a lower vessel 150 each connected in the vertical direction, and the central axes of the upper and lower vessels are aligned vertically or are positioned approximately to the extent that they can be regarded as aligned vertically, and the inner side wall surface has a cylindrical shape.

[0055] In other words, the arm 142 is disposed in the space inside the hollow support beam 206. The arm 142 extends horizontally, and one end of the arm 142 extending horizontally is connected to the bottom of the outer periphery of the sample stage 140, and is configured to move up and down in the space inside the hollow support beam 206. In addition, the other end of the arm 142 is connected to an arm drive unit (the arm drive unit includes a drive actuator 143, a ball screw 214, and a motor 215) that moves the arm 142 up and down.

[0056] A gate 131, which is an opening that communicates between the inside and outside of the vacuum container, is disposed on the outer wall of the upper container 130, and the wafer 200 is placed on the sample stage 140 by a transfer robot through the gate 131. During plasma processing, the opening (gate 131) is vacuum-sealed by a gate valve (not shown), and the vacuum seal is released only when the wafer 200 is transferred.

[0057] The sample stage block is roughly divided into a first sample stage base 141 constituting the lower part, a sample stage 140 mounted on and connected to the first sample stage base 141 and including a cylindrical head part 201, and an outer peripheral ring 202 arranged in a ring shape above the first sample stage base 141 and surrounding the outer peripheral side of the sample stage 140. In this embodiment, these parts are configured to be detachable and replaceable from the vacuum vessel or the lower part when the inside of the vacuum vessel is opened to atmospheric pressure during maintenance work such as part replacement or inspection of the plasma processing apparatus 100.

[0058] The head unit 201 constituting the upper part of the sample stage 140 is configured with a base plate 203 which is a circular metal plate-like member, a metal substrate having a disk or cylinder shape placed on the top of the base plate, and a dielectric film arranged to cover the circular upper surface of the substrate. The base plate 203 and the substrate having the dielectric film are connected as described later and configured to be detachable as a single unit.

[0059] The second sample stage base 145 is a circular member that functions as a stand for placing the sample stage 140 above the second sample stage base 145, and the head portion 201 including the sample stage 140 is placed above the center of the second sample stage base 145, and the upper surface of the outer periphery of the second sample stage base 145 is connected to the lower surface of the outer periphery of the base plate 203.

[0060] The center of the second sample stage base 145 is circular with a cross section that is convex downward compared to the outer periphery of the second sample stage base 145, and the space surrounded by the upper surface, side surface, and lower surface of the base plate 203 of the center of the second sample stage base 145 is a storage space 204. As described later, the storage space 204 is a space in which at least the head part 201 descends when the wafer 200 is transported, and a passage for extending a plurality of fixing pins 205 for separating the wafer 200 from the sample stage 140, a power supply connector 211 to the head part 201 coming out of the base plate 203, a sensor, and the like can be arranged inside, and the pressure is set to atmospheric pressure or the same as that inside the building in which the plasma processing apparatus 100 is installed, and the bottom surface of the center of the second sample stage base 145 has an opening at least large enough to wire cables, etc. connected to the head part 201.

[0061] The bottom surface of the outer periphery of the second sample stage base 145 is an area where the arm 142 that drives the sample stage 140 up and down and the outer bellows 146 are fastened. As described above, the center of the second sample stage base 145 has a storage space 204 surrounded by the lower surface of the base plate 203 at the top, and compared to the bottom surface of the center of the second sample stage base 145, the bottom surface of the outer periphery of the second sample stage base 145 is higher than the minimum face distance of the outer bellows 146, and there is enough space to place the bellows 146.

[0062] The first sample stage base 141 is configured to include a ring-shaped base ring 207 that constitutes the outermost periphery and is sandwiched between the upper vessel 130 and the lower vessel 150 at the top and bottom to constitute a vacuum vessel, a central cylinder having a cylindrical shape arranged at the center side of the base ring 207, and a plurality of support beams 206 that are integrally formed by connecting these. In this embodiment, the inner circumference of the base ring 207 and the outer circumference of the central cylinder have cylindrical shapes with different radii arranged at horizontal positions where the centers in the vertical direction coincide or are approximately equal to each other, and the support beams 206 are arranged so that their axes are radially arranged from the position of the central axis along the radial direction and the angles between the axes of adjacent ones are equal or are approximately equal to each other. In addition, the first sample stage base 141 has a cylindrical recess with a lower center height of the central cylinder compared to the upper surface of the base ring 207, and this recess is at least high enough to accommodate the central bellows 147 and the fixing pin 205. In this embodiment, the recess in the center of the first sample stage base 141 is a space with a larger diameter than the convex portion in the center of the second sample stage base 145, but the recess in the center of the first sample stage base 141 may be smaller as long as the central bellows 147 and the fixing pin 205 can be positioned.

[0063] The first sample stage base 141 is a member connected to the second sample stage base 145 described above by a plurality of outer bellows 146 and a central bellows 147, and the central bellows 147 hermetically seals the processing chamber 110 and the storage space 204. Therefore, the storage space 204 is a space in which the lower surface of the base plate 203, the upper surface of the center of the second sample stage base 145, the side surface of the center of the second sample stage base 145, the inside of the central bellows 147, the inside of the hollow support beam 206, and the upper surface of the sample stage cover 216 are connected to each other, and each connection point is vacuum-sealed by an O-ring, and the pressure is the same as atmospheric pressure or the pressure inside the building in which the plasma processing apparatus 100 is installed. The connected storage space 204 serves as a wiring path for power supply cables to the head unit 201 connected to the base plate 203.

[0064] At least two driving actuators 143 as arm driving units are arranged on the outer periphery of the base plate 160 at symmetric angles with the central axis of the first sample stage base 141, and are composed of a ball screw 214, a motor 215, and members supporting them. The arm 142 and the ball screw 214 are connected outside the plasma processing apparatus 100. The ball screw 214 is connected to the motor 215, and the driving actuator 143 is equipped with a guide (not shown) that assists the linear motion of the arm 142. Although not shown, the driving actuators 143 are connected to each other by communication cables, and the rotation angle and rotation speed of the motor 215, i.e., the height of the arm 142, are controlled so as to be synchronized.

[0065] In the above-mentioned storage space 204, in addition to the extending passages of the multiple fixing pins 205, piping for a coolant supplied to the head unit 201 and wiring such as a power supply cable to a sensor or an electrode are arranged. The central bellows 147 in which the wiring is arranged has an internal cylindrical space, and the internal space is limited to use as a wiring path for a power supply cable to the head unit 201. The peripheral bellows 146 has an internal cylindrical space, and the internal space is limited to use as a connection path for the arm 142 fastened to the second sample stage base 145. The inside of the hollow support beam 206 is a part of the storage space 204, and is a space in which piping and cables connecting the sample stage 140 and a power source or a coolant supply source arranged outside the plasma processing apparatus 100 are arranged, or a space in which the arm 142 fastened to the second sample stage base 145 is installed.

[0066] In other words, the storage space 204 can be regarded as a passage that connects the space outside the plasma processing device 100 at atmospheric pressure to a cylindrical cavity that surrounds the space below the bottom surface of the sample stage 140 and in which the end of a coaxial cable 210 described below that is connected to a power supply connector 211 described below is located, and the arm 142 is positioned within this passage.

[0067] A columnar member 1421 is disposed at one end of the arm 142. The columnar member 1421 is configured to connect the arm 142 and the bottom of the outer periphery of the sample stage 140 to support the sample stage 140. A plurality of outer periphery bellows 146 are provided around the columnar members 1421. The plurality of outer periphery bellows 146 are disposed around the columnar member 1421 between the upper part of the cylindrical cavity and the bottom of the outer periphery of the sample stage 140, and expand and contract with the vertical movement of the arm 142, hermetically sealing the space between the inside of the cavity and the inside of the processing chamber 110.

[0068] The temperature sensors 212 are inserted into a plurality of recesses disposed inside the substrate of the sample stage 140 to detect the temperature of the substrate. One end of each of the temperature sensors 212 is disposed inside the storage space 204. The other end of each of the temperature sensors 212 is connected by a cable through the space inside the hollow support beam 206 to the base ring 207 or a vessel controller 208 disposed outside the plasma processing apparatus 100, and the temperature sensors 212 and the vessel controller 208 can communicate with each other via the cable. The vessel controller 208 is configured to be able to receive the output of each of the temperature sensors 212 transmitted during processing of the wafer 200.

[0069] The head section 201 constituting the sample stage 140 of this embodiment is configured to include a base plate 203, an insulating member (not shown) placed thereon, and a metal base material (not shown) placed thereon. A dielectric film (not shown) containing ceramics such as yttria or alumina that constitutes a mounting surface on which the wafer 200 is placed is disposed on the disk or cylindrical upper surface of the head section 201. In addition, a seal member such as an O-ring is sandwiched between each of the above-mentioned components to connect them together, and the interior of the plasma processing apparatus 100 and the internal space of the sample stage block (141, 140, 202) that communicates with the storage space 204 are hermetically sealed. The head section 201 is attached to the second sample stage base 145 as a single member and is configured to be removable upward.

[0070] Further, a metal base material (not shown) which is a component of the head unit 201 is supplied with high frequency power having a frequency lower than the frequency of the electric field for forming plasma during processing of the wafer 200, and a bias potential is formed on the wafer 200 placed on the upper surface of the dielectric film. In this embodiment, a power supply connector 211 for supplying high frequency power for forming a bias potential from the second high frequency power source 148 is inserted into the base material, electrically connected, attached to the head unit 201, and wired with a coaxial cable 210. The coaxial cable 210 exits the power supply connector 211, passes through the central bellows 147 in the storage space 204 and a coaxial cable path 213 provided along the arm 142, and exits outside the plasma processing apparatus 100, whereupon the cable 210 is connected to the second high frequency power source 148. In this embodiment, the coaxial cable path 213 is a path that runs from the storage space 204 to the outside of the plasma processing apparatus 100 along the arm 142, and has an opening at least large enough for the coaxial cable 210 to pass through, and is fixed in position by a fixture (not shown) installed at the end of the arm 142. That is, inside the arm 142, an arm passage 213 is provided that communicates between the space 204 inside the hollow portion and the space outside the plasma processing apparatus 100 outside the sample stage base 145, which is at atmospheric pressure, and the coaxial cable 210 is arranged inside the arm passage 213 and fixed in position. However, if the path 213 can be fixed in position, it may be provided, for example, on the side of the arm 142 and fixed in position at multiple points along the arm 142 with brackets or the like. In addition, since the arm 142 is connected to the head unit 201 including the power supply connector 211 and the second sample stage base 145, the positional relationship between them is unchanged regardless of the vertical drive by the drive actuator 143. Therefore, even when the head unit 201 is driven vertically, the coaxial cable 210 does not come into contact with or deform with other cables or the inner wall inside the storage space 204, and it is possible to suppress the impedance change of the high-frequency power caused by the deformation of the cable 210 and form a stable plasma.

[0071] The inside of the hollow support beam 206 where the arm 142 is not arranged is a wiring path for the coolant piping, the cable of the temperature sensor 212, the power supply cable, etc., except for the coaxial cable 210, and these are collected and fixed by a cable fixing device 209 connected to the outer periphery of the hollow support beam 206 to prevent them from sliding outside the plasma processing apparatus 100. The fixing device is a metal or resin fixing device having an opening larger than at least the cross-sectional area of ​​the cables to be collected and fixed, and is connected to the base ring 207. The cables fixed by the fixing device are arranged with sufficient slack so that they do not come into contact with the inner wall or the central bellows 147 even when the head part 201 moves up and down and slides inside the storage space 204.

[0072] Furthermore, a refrigerant flow path is arranged in the metal base material, which is a component of the head part 201, through which a refrigerant whose temperature is adjusted to a value within a predetermined range is supplied and circulated, although this is not shown. The temperature of such a refrigerant is adjusted in the second temperature controller 149 equipped with a temperature regulator using a refrigeration cycle such as a chiller, and the refrigerant is supplied to the refrigerant flow path inside the base material of the head part 201 by a pump inside the second temperature controller 149. The refrigerant discharged after heat exchange with the base material of the head part 201 is returned to the second temperature controller 149 through the refrigerant flow path, where it is temperature-adjusted again, and then supplied again to the refrigerant flow path inside the base material. As described above, the refrigerant piping connecting the refrigerant flow path and the second temperature controller 149 is arranged in the storage space 204 including the space of the hollow support beam 206.

[0073] Three fixing pins 205 are installed at equal intervals in a recess in the center of the first sample stage base 141. The fixing pins 205 also extend to the storage space 204 and head section 201 inside the second sample stage base 145. Since the portion to which the fixing pins 205 extend is in a vacuum atmosphere, the storage space 204 is vacuum-sealed by a bellows, and a through hole is provided in the head section 201 so as to avoid the metal base material and the coolant flow path described above. In other words, a through hole through which the fixing pins 205 are installed is provided in the head section 201.

[0074] A sample stage cover 216 is detachably attached to the bottom surface of the central cylinder constituting the first sample stage base 141, and is attached to the central cylinder so as to airtightly seal and close the internal storage space 204. The storage space 204 includes a cylindrical space that is disposed inside each support beam 206 and base ring 207 and communicates with the inside of the central cylinder and the outside of the plasma processing apparatus 100 through the central cylinder. As described above, when performing maintenance work such as part replacement or inspection of the head unit 201, after removing the sample stage cover 216, the coaxial cable, the power supply wiring cord, the temperature control wiring cord, and the coolant pipe connected to the bottom surface of the base plate 203 are disconnected from the storage space 204 below the central bellows 147, the fastening bolts that fix the base plate 203 and the second sample stage base 145 are removed, and the head unit 201 is pulled up vertically.

[0075] The vessel controller 208 includes a calculation device, is disposed outside the plasma processing apparatus 100 or the vacuum vessel, and is communicatively connected to a plurality of devices such as the sample stage 140 and the drive actuator 143. The vessel controller 208 receives signals from the communicatively connected devices, detects information contained in the signals, and transmits command signals to these devices to adjust their operations. Note that in this example, the vessel controller 208 and the drive actuator 143 are configured so that they cannot be disconnected, but this is not limiting. The vessel controller 208 and the drive actuator 143 may be configured so that they can be disconnected.

[0076] The container controller 208 of this embodiment includes a computing unit made of semiconductor devices, an interface for transmitting and receiving signals between the device and the device, and a memory device such as a RAM or ROM for storing and recording or storing data internally, or a storage device such as a hard disk drive. These circuits (the computing unit, the interface, the storage device) are connected to be able to communicate with each other inside the container controller 208. The container controller 208 receives a signal from the outside through the interface, and the computing unit detects information from the signal and stores the information in the storage device. The computing unit also reads out software previously stored inside the storage device, calculates a command signal corresponding to the information inside the signal (the information stored in the storage device) according to an algorithm written in the software, and transmits the command signal to the device to be controlled through the interface.

[0077] The storage device of the container controller 208 may be housed inside the container controller 208 or may be disposed externally so as to be able to communicate with the container controller 208. The container controller 208 of this embodiment is connected to a temperature sensor 212 so as to be able to communicate with the temperature sensor 212.

[0078] Fig. 4 is a vertical cross-sectional view showing a state where a driving unit including a sample stage 140, a second sample stage base 145, and an arm 142 is lowered to the lowest position by a driving actuator 143, which has the same configuration as the embodiment shown in Fig. 3. The state where a wafer 200 is transferred or unloaded from the plasma processing apparatus 100 before or after plasma processing is shown, respectively. In Fig. 4, the description of the parts with the reference numerals shown in Fig. 3 described above will be omitted unless necessary.

[0079] The multiple peripheral bellows 146 and the central bellows 147, which are connected between the first sample stage base 141 and the second sample stage base 145 and vacuum seal the processing chamber 110 and the storage space 204, have contracted by the amount of drive of the drive actuator 143, compared to the schematic diagram of the upward movement shown in Figure 3.

[0080] As described above, the coaxial cable 210 passes through a dedicated coaxial cable path 213 provided inside or on the side of the arm 142 and is connected to the second high frequency power supply 148 disposed outside the plasma processing apparatus 100. As can be seen by comparing Figures 3 and 4, the cable 210 is fixed in position within the storage space 204 by passing through the coaxial cable path 213, and it is possible to suppress impedance changes in the high frequency power due to deformation of the cable 210.

[0081] As described above, the inside of the hollow support beam 206 where the arm 142 is not arranged is a wiring path for the coolant piping, the cable of the temperature sensor 212, the power supply cable, etc., excluding the coaxial cable 210, and in order to prevent them from sliding outside the plasma processing apparatus 100, they are collected and fixed by a cable fixing device 209 connected to the outer periphery of the hollow support beam 206. The fixing device 209 is a metal or resin fixing device having an opening larger than the cross-sectional area of ​​at least the cables to be collected and fixed, and is connected to the base ring 207. The cables fixed by the fixing device 209 are arranged with a sufficient slack length so that they do not touch (do not come into contact with) the inner wall of the storage space 204 and the central bellows 147 even when the head unit 201 moves up and down and slides inside the storage space 204.

[0082] The three fixing pins 205 separate the wafer 200 from the sample stage 140 and hold it only when the wafer 200 is placed on the sample stage 140 via the gate 131 for plasma processing, or when the wafer 200 after plasma processing is carried out of the plasma processing apparatus 100 via the gate 131 by a transfer robot (not shown). In this embodiment, when the wafer 200 is carried in or out, the driving actuator 143 places the wafer 200 on the sample stage 140 in a positional relationship lower than the height of the upper tips of the fixing pins 205. This causes the back surface of the wafer 200 to be separated from the wafer 200 on the sample stage 140 by the fixing pins 205. On the other hand, during plasma processing, the wafer 200 on the sample stage 140 is placed in a positional relationship higher than the height of the upper tips of the fixing pins 205. This brings the back surface of the wafer 200 into contact with the wafer 200 on the sample stage 140. In this state, the plasma processing is performed or is in progress. The length of the fixing pin 205 is determined by the position of the gate 131, and the vertical drive stroke of the drive actuator 143 must be such that the sample stage 140 exceeds the height of the fixing pin 205 during the plasma processing.

[0083] Although the present disclosure has been specifically described above based on examples, it goes without saying that the present invention is not limited to the above-described embodiments and examples, and various modifications are possible. [Explanation of symbols]

[0084] 100: plasma processing apparatus, 101: 1st high frequency power supply, 102: Cover member (quartz plate), 103: shower plate, 104: Gas introduction ring, 105: Quartz inner cylinder, 106: Coil, 107: O-ring, 110: Processing room, 120: discharge block, 121: Heater, 122: Lower ring, 123: first temperature controller; 124: Discharge chamber 125: Earth Ring, 130: upper container, 131: Gate, 140: sample stage, 141: First sample stage base, 142: Arm, 143: drive actuator, 144: Sample stage bottom cover, 145: second sample stage base, 146: Peripheral bellows, 147: central bellows, 148:Second high frequency power supply, 149: second temperature controller; 150: Lower container, 160: Base plate, 161: Exhaust cover, 162: Cylinder, 170: exhaust pump, 180: Prop, 200: wafer, 201: Head section, 202: outer ring, 203: Base plate, 204: Storage space, 205: fixing pin, 206:Hollow support beam, 207: Base Ring, 208: container controller, 209: Cable fasteners, 210: coaxial cable, 211: power supply connector, 212: temperature sensor, 213: coaxial cable path, 214: Ball screw, 215: motor, 216: Sample stage cover.

Claims

1. a processing chamber disposed within the vacuum vessel, within which plasma is formed; a sample stage disposed inside the processing chamber and on which a semiconductor wafer to be processed using the plasma is placed; A member constituting the vacuum vessel, a ring-shaped sample stage base connected to the sample stage at an outer periphery of the sample stage; and a cylindrical upper vessel placed on the sample stage base; a plurality of support beams connecting the sample stage and the sample stage base; an arm that is disposed in the space inside the support beam, and has one end extending in a horizontal direction and connected to a bottom of the outer periphery of the sample stage so as to move up and down in the space inside the support beam; a drive unit that is disposed outside the vacuum vessel and is connected to the other end of the arm to move the arm in a vertical direction; a cable electrically connected to an electrode to which high frequency power is supplied via a connector arranged at the bottom of the sample stage and through which the high frequency power flows, the cable being fixed to the arm and moving vertically as the arm is driven.

2. 2. The plasma processing apparatus according to claim 1, The support beam is a passage that communicates between a cylindrical cavity that is a space below a bottom surface of the sample stage and that surrounds a space in which an end of the cable connected to the connector is disposed, and a space outside the sample stage base and that is at atmospheric pressure outside the plasma processing apparatus; The arm is disposed within the passageway.

3. 3. The plasma processing apparatus according to claim 2, a columnar member that is disposed at one end of the arm and connects the arm to a bottom of the outer periphery of the sample stage to support the sample stage; a peripheral bellows that is disposed around the columnar member between the top of the cylindrical cavity and the bottom of the outer periphery of the sample stage, and expands and contracts as the arm moves up and down to hermetically seal the space between the inside of the cavity and the inside of the processing chamber.

4. 3. The plasma processing apparatus according to claim 2, an arm internal passage is provided inside the arm, the arm internal passage communicating between a space inside the hollow portion and a space outside the sample stage base and outside the plasma processing apparatus, the space being at atmospheric pressure; The cable is disposed inside the arm passage and its position is fixed.

5. 3. The plasma processing apparatus according to claim 1, The vacuum vessel comprises: a base plate on which the sample stage base and the upper vessel are placed with the inside and outside of the sample stage base and the upper vessel hermetically sealed to constitute the vacuum vessel; The plasma processing apparatus, wherein the driving unit is disposed on the base plate.

6. 3. The plasma processing apparatus according to claim 1, The vacuum vessel comprises: a lower vessel having a cylindrical shape disposed below the sample stage base and on which the sample stage base is placed; a base plate on which the lower vessel, the sample stage base and the upper vessel are placed with the inside and outside of the vessel hermetically sealed, constituting the vacuum vessel; The driving unit is disposed on the base plate.

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