Substrate stage and vacuum processor

Abstract

To provide a substrate stage which is capable of supporting a warped substrate in a posture with the specific surface thereof upward and suppressing as much as possible adhesion of fine particles to the substrate after vacuum processing.SOLUTION: A substrate stage includes a base table 5 and an annular wall 6 supporting a lower surface outer peripheral edge part of a substrate Sw arranged above a base table upper surface across a gap. An upper surface inner edge part is formed with a first inclined support surface 64 which is inclined downward and radially inward and in which the lower surface outer peripheral edge part is seated. An inner wall of the annular wall is formed with a plurality of receiving recesses 65 recessed radially outward and arranged at intervals in a circumferential direction. Movable bodies 7 are housed in the receiving recesses, supporting projections 75 each having a second inclined support surfaces 75a inclined downward and radially inward are each formed on an upper surface of each of the movable bodies 7, and configured to be able to support the lower surface outer peripheral edge part at three or more positions in the circumferential direction. Thus, the substrate stage is configured to deliver the substrate to the first inclined support surface 64 when each of the movable bodies is moved downward from the state that the substrate is supported by each support projection.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a substrate stage on which a substrate to be processed, such as a semiconductor wafer, is placed in a vacuum chamber for performing a predetermined vacuum process on the substrate, and to a vacuum processing apparatus including the substrate stage. [Background technology]

[0002] Known examples of this type of substrate stage and vacuum processing apparatus equipped with this substrate stage include those described in Patent Document 1. The substrate stage includes a base and an annular wall that abuts against the outer peripheral edge of the lower surface of a substrate to be processed (hereinafter referred to as "substrate") and supports the outer peripheral edge of the lower surface of the substrate with a gap from the upper surface of the base. The annular wall is composed of a fixed wall portion and multiple movable wall portions having a predetermined arc length, and the movable walls are configured to be movable up and down relative to the fixed wall portions. The annular wall is generally made of ceramics such as alumina or silicon carbide.

[0003] When an unprocessed substrate is carried into the substrate stage, each movable wall portion is synchronously moved upward from the upper surface of the base to a predetermined height position, and in this state, the substrate supported by the robot hand of the vacuum transport robot is transferred to each movable wall portion, and the lower surface outer periphery of the substrate is seated on the upper surfaces of each movable wall portion extending in an arc shape. Then, when each movable wall portion is synchronously moved downward, the remaining portion of the lower surface outer periphery of the substrate is also seated on the fixed wall portion. The upper surface inner edge of the fixed wall portion and the movable wall portion is formed as an inclined support surface that is inclined downward toward the inside in the radial direction and against which the lower surface outer periphery of the substrate abuts. As a result, even if the substrate is warped downward in a concave shape, for example, one surface of the substrate on which a device structure has already been formed is prevented from coming into contact with the upper surface of the base and being damaged, and the substrate can be supported with the other surface facing upward by the inclined support surface formed on the fixed wall portion and the movable wall portion.

[0004] When the processed substrate is to be removed from the substrate stage, the movable wall is again raised to a predetermined height position, and the substrate is returned to a state in which the upper surface of the movable wall supports the outer peripheral edge of the lower surface of the substrate. Then, the robot hand is inserted into the space between the substrate and the annular wall, and the processed substrate is transferred to the robot hand. However, in the above-mentioned conventional example, it was found that when the substrate is repeatedly transferred in and out of the substrate stage, many fine particles (above a predetermined size) adhere to the substrate immediately after the vacuum processing. Therefore, the inventors of the present application have conducted intensive research and have come to the following findings. That is, in the above-mentioned conventional example, the movable wall has a relatively long arc-shaped inclined support surface, so that the contact area with the substrate is large. Therefore, when the substrate is transferred from the robot hand of the transport robot to the movable wall, or when the movable wall is moved up and down while supporting the substrate, the substrate vibrates, and the outer peripheral edge of the substrate repeatedly collides with the inclined support surface and is scraped off, which has come to the finding that this becomes a new source of particle generation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-77744 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made based on the above findings, and its object is to provide a substrate stage and vacuum processing apparatus which are capable of minimizing the adhesion of fine particles to a substrate immediately after film formation, even when film formation processes are repeated, without compromising the function of supporting a warped substrate with the other surface facing upwards without damaging one surface of the substrate. [Means for solving the problem]

[0007] In order to solve the above problems, the substrate stage of the present invention, which is placed in a vacuum chamber in which a predetermined vacuum processing is performed on a substrate to be processed and in which the substrate to be processed is placed, comprises a base and an annular wall which supports the outer peripheral edge of the lower surface of the substrate to be processed with a gap from the upper surface of the base, a first inclined support surface is formed on the inner edge of the upper surface of the annular wall, which slopes downward in the radially inward direction and on which the outer peripheral edge of the lower surface of the substrate to be processed sits, and a plurality of receiving recesses are formed at intervals in the circumferential direction and recessed radially outward in the inner wall of the annular wall, the substrate stage further comprises movable bodies which are respectively stored in the receiving recesses and a driving body which moves each movable body up and down in synchronous with each other, and a support protrusion having a second inclined support surface which slopes downward in the radially inward direction is provided on the upper surface of each movable body, so that the outer peripheral edge of the lower surface of the substrate to be processed can be supported at three or more points in the circumferential direction of the substrate to be processed by the second inclined support surface of each support protrusion, and the substrate to be processed is transferred to the first inclined support surface by the downward movement of each movable body from a state in which the substrate to be processed is supported by each support protrusion. In this case, it is preferable that the support projections are made of heat-resistant resin and are detachably attached to the upper surface of each movable body.

[0008] According to the present invention, when an unprocessed substrate is carried into the substrate stage, each movable wall part is synchronously moved upward from the upper surface of the base to a predetermined height position, and in this state, the substrate supported by the robot hand of the vacuum transport robot is transferred to the support protrusion of each movable wall part. At this time, the outer peripheral edge of the lower surface of the substrate is seated on the second inclined support surface of each support protrusion, and the substrate is supported at three or more points in its circumferential direction. Then, when each movable wall part is synchronously moved downward and exceeds a height position where the first inclined support surface and the second inclined support surface are on the same horizontal plane, the remaining part of the substrate except for the lower outer peripheral edge part located above each movable body is seated on the first inclined support surface, and the substrate is supported only by the annular wall. At this time, the movable body is located in the receiving recess with a small gap.

[0009] In this way, in the present invention, a configuration is adopted in which the outer peripheral portion of the lower surface of the substrate is supported at at least three points only by the second inclined support surface of each support protrusion, and it has been confirmed that by making the contact area with the substrate as small as possible, the adhesion of fine particles (above a predetermined size) to the substrate immediately after film formation can be dramatically reduced even if the film formation process is repeated. In this case, if the support protrusions are made of a heat-resistant resin that is softer than the substrate (i.e., has cushioning properties), it is effective in further suppressing the generation of dust. Here, when the substrate is a semiconductor wafer and the outer peripheral portion of the substrate is a bevel portion, the inclination angle of the first inclined support surface of the fixed wall portion and the second inclined support surface of the support protrusion with respect to the upper surface of the base may be set in the range of 4 degrees to 40 degrees depending on the substrate size. As a result, even if the semiconductor wafer is warped downward in a concave shape, the substrate can be supported with a minute gap to reliably prevent contact with the upper surface of the base and with only the bevel portion seated on the first inclined support surface, and further, when a predetermined vacuum process is performed on the substrate using plasma, so-called discharge leakage into the gap between the upper surface of the base or the receiving recess of the annular wall and the movable body can be prevented. Furthermore, if the support protrusions become deformed due to repeated loading and unloading of the substrate, it is advantageous that only the support protrusions made of heat-resistant resin need to be replaced.

[0010] In order to solve the above problems, the vacuum processing apparatus of the present invention, which includes a vacuum chamber equipped with the substrate stage and a film forming means for performing a film forming process in the vacuum chamber under a vacuum atmosphere on the upper surface of a substrate supported by the substrate stage, is characterized in that it further includes a cover that covers the upper surface of the annular wall with a vertical gap. This makes it possible to suppress deposition of a film on the annular wall as much as possible when performing a film forming process on a substrate in the vacuum processing apparatus. Therefore, it is possible to suppress the annular wall from becoming a source of new particles and the deposition of fine particles (above a predetermined size) on the substrate to be processed immediately after film formation.

[0011] In the present invention, when the vacuum chamber is provided with an adhesion prevention plate that is located around the annular wall and has a movable part that can move up and down, it is preferable that the cover ring is held by the movable part, which is advantageous in that the substrate can be easily transferred to the support protrusions by the vacuum transfer robot without interfering with the cover ring.

[0012] Furthermore, when the film-forming means is a sputtering cathode disposed in a vacuum chamber facing the substrate stage, and a conductive cylindrical block body is disposed around the substrate stage facing the plasma atmosphere formed in the vacuum chamber, it has been confirmed that, if an opening is formed in the movable part located above the block body with an opening ratio of 50% or more, film formation can be achieved with stable plasma even when an insulating target is sputtered to form a film on the substrate to be processed.

[0013] In addition, when forming a silicon nitride film on a substrate to be processed by reactive sputtering, for example, it is common to periodically carry out so-called dummy processing. In this case, if the substrate to be processed is transported in one direction around the substrate stage while the movable body is moved upward, and a transport means is provided in the vacuum chamber to support a shutter plate and transport the shutter plate from the direction opposite to the transport direction of the substrate to a position where it can be handed over to the upper surface of each movable body, it is advantageous that the dummy processing can be easily carried out without transporting the shutter plate from the atmosphere. [Brief description of the drawings]

[0014] [Figure 1] 1 is a diagram showing a schematic configuration of a vacuum processing system including a substrate stage according to an embodiment of the present invention and a vacuum processing apparatus including the substrate stage; [Diagram 2] 1A is a cross-sectional plan view of the load lock chamber, and FIG. 1B is a cross-sectional view taken along line IIb-IIb in FIG. [Diagram 3]4A is a perspective view of the robot hand, FIG. 4B is a partially enlarged cross-sectional view illustrating how the substrate is supported by the protrusions, and FIG. 4C is a partially enlarged cross-sectional view illustrating how the substrate is supported by the support projections. [Figure 4] FIG. 2 is a cross-sectional view showing the sputtering apparatus of the present embodiment at a film formation position. [Diagram 5] FIG. 5 is an enlarged cross-sectional view of a main part of FIG. 4. [Figure 6] FIG. [Figure 7] FIG. 13 is a plan view illustrating a lower adhesion prevention plate having a covering. [Figure 8] 5 is a cross-sectional view showing the sputtering apparatus shown in FIG. 4 in its transport position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Below, with reference to the drawings, an embodiment of the substrate stage of the present invention and a vacuum processing apparatus equipped with this substrate stage will be described using as an example an example in which the "substrate to be processed" is a semiconductor wafer (hereinafter referred to as "substrate Sw") having a diameter of 300 mm, its "outer edge" is a bevel portion Sb formed by chamfering the outer edge surface of the semiconductor wafer (for example, a portion within 2 mm from the outer edge of the substrate Sw), and the "vacuum processing apparatus" is a sputtering apparatus that forms a specified thin film on the upper surface of the substrate Sw by a sputtering method.

[0016] Referring to FIG. 1, the CM is a cluster tool type vacuum processing system including a central transfer chamber Tc, a load lock chamber Lc arranged to surround the transfer chamber Tc, and a plurality of processing chambers Pc, and one of the processing chambers Pc constitutes a vacuum chamber of a sputtering apparatus as a vacuum processing apparatus including the substrate stage ST of this embodiment. A robot stage Rs is arranged on the side of the load lock chamber Lc facing away from the transfer chamber Tc. The robot stage Rs is provided with an atmospheric transfer robot Rt and a cassette Kw capable of stocking a plurality of substrates Sw. As the atmospheric transfer robot Rt, a multi-joint type robot capable of holding the substrate Sw by clamping the bevel portion Sb from both sides in the radial direction is used, and the substrate Sw can be transferred to the load lock chamber Lc in a posture in which one surface (the surface on which the device structure is formed) or the other surface faces vertically upward. As such an atmospheric transfer robot Rt, a known robot can be used, and detailed description thereof will be omitted here.

[0017] 2(a) and 2(b), although not shown or described, an exhaust pipe from a vacuum pump and a vent gas line for introducing vent gas are connected to the load lock chamber Lc, respectively, so that the inside of the load lock chamber Lc can be quickly switched between a vacuum atmosphere and an atmospheric atmosphere. A metal substrate support 1 is installed in the load lock chamber Lc. Three support pins 11 are protruding from the upper surface of the substrate support 1, positioned on the same circumference having a predetermined diameter equal to that of the substrate Sw. An inclined support surface 12 is formed on the upper surface of each support pin 11, which is inclined downward toward the inside in the radial direction, so that the substrate Sw held by the atmospheric transfer robot Rt can be placed in a position with one surface or the other surface facing vertically upward. In this case, the height of the support pins 11 is set so that a space can be secured between the lower surface of the substrate Sw and the substrate support 1, allowing the robot hand 21 of the atmospheric transfer robot Rt or the vacuum transfer robot Rv to enter. In addition, the inclined support surface 12 is inclined at an angle α1 in the range of 4 degrees to 30 degrees with respect to the flat upper surface of the support pin 11, and the substrate Sw is supported with only the bevel portion Sb seated on the inclined support surface 12 with a gap remaining from the upper surface of the substrate support table 1.

[0018] The transfer chamber Tc connected to the load lock chamber Lc via a gate valve Gv is connected to an exhaust pipe from a vacuum pump (not shown) so that a vacuum atmosphere of a predetermined pressure can be maintained. A vacuum transfer robot Rv is installed in the transfer chamber Tc. The vacuum transfer robot Rv is a so-called frog-lock type robot having two robot arms 22 with a transfer robot hand 21 at the tip for supporting the substrate Sw placed thereon, and two concentric rotating shafts 23a, 23b for rotating the robot arms 22. The robot arm 22 rotates or expands within the same plane by appropriately controlling the rotation direction and rotation angle of the rotating shafts 23a, 23b by a motor (not shown) provided outside the transfer chamber Tc. At this time, when the robot arm 22 expands or contracts, the robot hand 21 reciprocates along the same line. In each processing chamber Pc, as described later, when the movable bodies 7, 7 are in the upwardly moved delivery position, the substrate Sw supported by the robot hand 21 is carried in from one direction around the substrate stage ST, and the processed substrate Sw is carried out from the same direction after being delivered to the robot hand 21. Although not specifically shown or described, the rotating shafts 23a, 23b are provided with driving means such as air cylinders, so that the robot hand 21 and the robot arm 22 can move up and down in addition to rotating or extending.

[0019] 3(a) to 3(c), the robot hand 21 connected to the robot arm 22 via the gear box 24 is made of a material that is heat-resistant and has a large friction coefficient, such as a plate material made of alumina or silicon carbide, in consideration of the possibility that the substrate Sw may be heated during film formation by the sputtering method. The robot hand 21 has a base end 21a connected to the gear box 24 and a pair of finger portions 21b that branch out in a bifurcated manner from the base end 21a and extend forward. A detection window 21c is provided at a predetermined position of the base end 21a so that the robot hand 21 can be detected by an optical sensor (not shown). Then, positioned on the same circumference with the same predetermined diameter as the substrate Sw, two strip-like extending protrusions 25 protruding upward are detachably attached to both circumferential sides of the detection window 21c on the upper surface of the base end 21a with fastening means 26a such as screws, and upwardly protruding support protrusions 27 are similarly detachably attached to the upper surfaces of both tips of both finger portions 21b with fastening means 26b such as screws.

[0020] The ridges 25 and the support projections 27, which have the same height from the upper surface of the robot hand 21, are made of a heat-resistant resin that is softer than the substrate Sw (i.e., has cushioning properties) in consideration of the possibility that the substrate Sw may be heated and of suppressing the generation of dust when the substrate Sw is handed over to the robot hand 21 or transported. An example of such a heat-resistant resin is a fluorine-based resin with a heat-resistant temperature of 200°C. In addition, on the upper surfaces of the ridges 25 and the support projections 27, inclined support surfaces 25a and 27a are formed, respectively, which are inclined downward toward the inside in the radial direction and on which the bevel portion Sb of the substrate Sw sits, and upward steps 25b and 27b are formed on the outer peripheries of the inclined support surfaces 25a and 27a, respectively. In this case, the inclined support surfaces 25a, 27a are inclined at an angle α2 in the range of 4 degrees to 30 degrees with respect to the upper surface of the robot hand 21, and even if the substrate Sw is warped downward in a concave shape, the substrate Sw can be supported in a state where contact with the upper surface of the robot hand 21 can be reliably prevented with a small gap and where only the bevel portion Sb is seated at four points in the circumferential direction on the inclined support surfaces 25a, 27a of the protrusions 25 and the support protrusions 27. In this embodiment, since the detection window 21c is formed, the protrusions 25, 25 are provided separately into two parts in the circumferential direction, but if the detection window 21c is not opened, the protrusions 25 may be formed integrally.

[0021] By configuring the robot hand 21 as described above, when the substrate Sw is transported while being supported by the robot hand 21, a part of the bevel portion Sb of the substrate Sw is in line contact with the inclined support surface 25a of the pair of relatively long protrusions 25, 25, and at least two circumferential points of the remaining bevel portion Sb are in contact with the inclined support surface 27a of the support protrusion 27, so that the substrate Sw is prevented from shifting due to frictional resistance and can be transported stably. Furthermore, since there are upward steps 25b, 27b on the outer periphery of the inclined support surfaces 25a, 27a, for example, even if the substrate Sw moves as if crawling up the inclined support surfaces 25a, 27a due to the inertial force when the robot hand 21 stops moving, the momentum is reduced by abutting against the steps 25b, 27b, and the substrate Sw can be prevented from falling off the robot hand 21. Furthermore, since the protrusions 25 and the support protrusions 27 are attached so as to be freely detachable, if the protrusions 25 or the support protrusions 27 become deformed due to repeated transportation of the substrate Sw, it is advantageously necessary to replace only the protrusions 25 or the support protrusions 27.

[0022] In each of the processing chambers Pc, which are connected to the transfer chamber Tc via a gate valve Gv, various devices are provided according to the vacuum processing to be performed on one side or the other side of the substrate Sw. In any one of the processing chambers Pc, the substrate stage ST of this embodiment is provided so that a silicon nitride film can be formed on the other side of the substrate Sw by sputtering. This will be described below with reference to FIGS. 4 to 8.

[0023] As shown in FIG. 4, an exhaust pipe 31a is connected to the processing chamber Pc, which is connected to a vacuum pump unit 31 including a turbo molecular pump, a rotary pump, or the like, and the inside of the processing chamber Pc is kept at a predetermined pressure (for example, 1×10 -5The processing chamber Pc can be evacuated to a vacuum pressure of 1000 MPa (1 Pa). A gas pipe 32a, which is connected to a gas source (not shown) and has a mass flow controller 32 interposed therein, is connected to the side wall of the processing chamber Pc, and a sputtering gas can be introduced into the processing chamber Pc at a predetermined flow rate. The sputtering gas used is argon gas as a rare gas for discharge and nitrogen gas as a reactive gas. A silicon target 4 is provided at the upper part of the processing chamber Pc. A backing plate 41 is bonded to the target 4 by a bonding material (not shown), and the target 4 is placed on the upper part of the side wall of the processing chamber Pc via an insulator 43 with its sputtering surface 42 facing downward. An output from a sputtering power supply 44 is also connected to the target 4. A known pulse DC power supply or a high-frequency power supply can be used as the sputtering power supply 44, and power of a predetermined frequency (for example, 10 kHz to 40 MHz) can be input to the target 4 during sputtering. The substrate stage ST of this embodiment is placed at the lower part of the processing chamber Pc, facing the target 4.

[0024] The substrate stage ST includes a base 5 having an outline one size larger than the substrate Sw, which is provided on the lower wall of the processing chamber Pc via an insulator 51, and an annular wall 6 supporting the bevel portion Sb of the substrate Sw with a gap from the upper surface of the base 5. A coolant passage 5a is formed in the base 5, and the upper surface of the base 5 can be cooled to a predetermined temperature (for example, −20 to 30° C.) by circulating a coolant supplied from a chiller (not shown) through the coolant passage 5a. Note that instead of the coolant passage 5a, a pipe may be attached to the lower surface of the base 5, and the coolant may be circulated through this pipe. As the coolant, a known coolant such as cooling water or ethylene glycol may be used. The base 5 is made of a material having high thermal conductivity, such as a metal such as aluminum, and its potential may be either a ground potential or a floating potential.

[0025] As shown in Figs. 5 and 6, the annular wall 6 is made of, for example, aluminum or silicon carbide, and includes a base 62 that is installed on the upper surface of the base 5 via an insulator 61. An annular protruding wall 63 that protrudes radially inward is formed on the upper inner edge of the base 62. A first inclined support surface 64 is formed on the upper inner edge of the protruding wall 63 of the annular wall 6, which is positioned on the same circumference having a predetermined diameter equivalent to that of the substrate Sw and inclined downward toward the radial inside, on which the bevel portion Sb of the substrate Sw is seated. The first inclined support surface 64 is inclined in the range of 4 degrees to 40 degrees with respect to the upper surface of the base 5, and even if the substrate Sw is warped downward in a concave shape, the substrate Sw can be supported with a small gap in a state in which contact with the driving plate 73 described later and the upper surface of the base 5 can be reliably prevented and only the bevel portion Sb is seated on the first inclined support surface 64. The protruding wall portion 63 is also formed with two receiving recesses 65 that are recessed radially outward and spaced 180 degrees apart in the circumferential direction, and each receiving recess 65 houses a movable body 7 therein.

[0026] The movable body 7 is made of, for example, aluminum or silicon carbide, like the annular wall 6, and includes an annular support wall portion 71 curved with the same curvature as the annular wall 6, and an annular mounting plate portion 72 formed at the lower end of the support wall portion 71 and protruding radially inward. The support wall portion 71 is sized to be equal to or greater than the vertical height of the receiving recess 65. Both ends of a plate-shaped driving plate portion 73 are connected to the lower surfaces of both mounting plates 72, 72, and a driving shaft 74a of an actuator 74 as a driving body provided to penetrate the central portion of the base 5 in the vertical direction is connected to the center of the lower surface of the driving plate portion 73. This allows the movable body 7 to move up and down freely in and out of the receiving recess 65 of the annular wall 6. In addition, a downward step portion 71a is formed on the inner peripheral side of the upper surface of the support wall portion 71, and the step portion 71a is arranged to be located on the same circumference as the first inclined support surface 64 is formed.

[0027] Three support protrusions 75 having second inclined support surfaces 75a inclined downward toward the inside in the radial direction are provided at the center of the upper surface of the step portion 71a of one support wall portion 71 and at both ends of the upper surface of the step portion 71a of the other support wall portion 71, respectively, and the second inclined support surfaces 75a of each support protrusion 75 can support the bevel portion Sb of the substrate Sw at three points in the circumferential direction. As described above, the support protrusions 75 are made of a heat-resistant resin that is softer than the substrate Sw (i.e., has cushioning properties), and as such a heat-resistant resin, as described above, a fluorine-based resin with a heat-resistant temperature of 200°C can be mentioned. In this case, the support protrusions 75 can be detachably attached by a fastening means (not shown) such as a screw. The second inclined support surfaces 75a are inclined at an angle of 4° to 40° with respect to the upper surface of the base 5, and the outer ends of the second inclined support surfaces 75a are made to be approximately flush with the upper surface of the support wall portion 71. As a result, even if the substrate Sw is warped concavely downward, the substrate Sw can be supported in a state where a small gap is maintained to reliably prevent contact with the drive plate portion 73 or the upper surface of the base 5, and only the bevel portion Sb is seated on the second inclined support surface 75a of each support protrusion 75.

[0028] A block body Ba is provided in the processing chamber Pc, positioned around the substrate stage ST. The block body Ba is made of a metallic cylindrical member, and its outer cylindrical surface is formed as a tapered surface that widens from its upper end to its lower end. The block body Ba also has a plurality of through holes Ba1 that penetrate in the vertical direction. The block body Ba is installed on the bottom surface of the earth-grounded processing chamber Pc, and serves as an earth during sputtering. An adhesion prevention plate 8 is provided in the processing chamber Pc, surrounding the film formation space Ps between the target 4 and the substrate stage ST (see FIG. 4). The adhesion prevention plate 8 is made of a material such as alumina or stainless steel, and has an upper adhesion prevention plate 81 and a lower adhesion prevention plate 82 as a movable part. The upper adhesion prevention plate 81 is made of a cylindrical member, and is suspended from the upper part of the processing chamber Pc via an attachment part 81a that protrudes radially inward from the upper end of the cylindrical member. On the other hand, the lower adhesion prevention plate 82 is formed of a disk-shaped plate material, and a cylindrical upright wall portion 82a is formed on the radially outer end thereof so as to stand upright toward the top.

[0029] A first opening 82b is formed in the central region of the lower adhesion prevention plate 82, and the inner peripheral edge of the first opening 82b is positioned directly above the bevel portion Sb of the substrate Sw supported by the first inclined support surface 64. In addition, in a portion of the lower adhesion prevention plate 82 located above the block body Ba around the first opening 82b, three second openings 82c having a smaller area than the first opening 82b are formed at predetermined intervals in the circumferential direction, as shown in Fig. 7. Then, an annular portion 82d remaining inside the second openings 82c serves as a covering ring in this embodiment, covering the upper part of the annular wall 6, thereby suppressing adhesion of sputtered particles to the annular wall 6 as much as possible.

[0030] In addition, if the aperture ratio of the second openings 82c is 50% or more based on the annular region 82e (region surrounded by a dashed line in FIG. 7) including each second opening 82c (in other words, if 50% or more of the upper surface of the earth block is exposed as viewed from the film formation space Ps side), the surface of the silicon target 4 is nitrided to form silicon nitride, and the silicon nitride on the surface is sputtered to form a high-resistance film on the surface of the substrate Sw, in which case the film formation can be continued in a stable plasma state. That is, the function of the block body Ba is not impaired. In this embodiment, the annular portion 82d equivalent to a cover ring is integrally formed with the lower adhesion protection plate 82, but this is not limited thereto, and a separate cover ring may be attached to the lower adhesion protection plate 82. In addition, a protrusion portion 82f protruding downward may be formed on the lower surface of the annular portion 82d, and a labyrinth structure may be formed together with the protrusion 66 formed at a predetermined position on the upper surface of the annular wall 6 to suppress the wraparound of sputtered particles and discharge leakage.

[0031] A drive shaft 83a from a drive means 83 such as a motor or an air cylinder, which extends through the bottom wall of the processing chamber Pc, is connected to the lower adhesion protection plate 82. The drive means 83 moves the lower adhesion protection plate 82 up and down between a film formation position shown in FIG. 4 where film formation by sputtering is performed and a transfer position shown in FIG. 8 where the lower adhesion protection plate 82 is moved up from the film formation position to a predetermined height position and the substrate Sw is transferred to the substrate stage ST by the vacuum transfer robot Rv. At the film formation position, the lower end of the upper adhesion protection plate 81 and the upper end of the standing wall portion 82a are designed to overlap each other in the vertical direction. The transfer of the substrate Sw from the cassette Kw to the substrate stage ST will be described below using the example of forming a silicon nitride film on the other surface of the substrate Sw.

[0032] A single substrate Sw is taken out of the cassette Kw of the robot stage Rs by the atmospheric transfer robot Rt and transferred to the load lock chamber Lc in the atmospheric atmosphere. At this time, the other surface of the substrate Sw is oriented so as to face upward, and the substrate Sw is transferred in this orientation into the load lock chamber Lc through an opening and closing door (not shown) formed in the load lock chamber Lc, and the substrate Sw is placed on the substrate support table 1 so as to be supported by each support pin 11 of the substrate support table 1. The substrate Sw is supported with only the bevel portion Sb seated on the inclined support surface 12 with a gap remaining from the upper surface of the substrate support table 1 (see FIG. 2). When the substrate Sw is placed, the opening and closing door is closed and the inside of the load lock chamber Lc is evacuated to a predetermined pressure. At this time, the transfer chamber Tc and the processing chamber Pc are in a state of being evacuated to a predetermined pressure.

[0033] When the load lock chamber Lc is evacuated to a predetermined pressure, the gate valve Gv is opened and the robot hand 21 of the vacuum transfer robot Rv receives the substrate Sw. At this time, the rotation direction and rotation angle of the rotation shafts 23a and 23b are appropriately controlled to cause the robot hand 21 to enter the gap between one surface of the substrate Sw and the upper surface of the substrate support table 1, and then the rotation shafts 23a and 23b are moved upward. As a result, the substrate Sw is supported in a state where a minute gap is maintained to reliably prevent contact with the upper surface of the robot hand 21 and where only the bevel portion Sb is seated on the inclined support surfaces 25a and 27a of the protrusions 25 and the support protrusions 27.

[0034] When the robot hand 21 receives the substrate Sw, the gate valve Gv between the transfer chamber Tc and the processing chamber Pc is opened, and the rotation direction and rotation angle of the rotating shafts 23a and 23b are appropriately controlled, so that the substrate Sw is transferred from the load lock chamber Lc to the processing chamber Pc via the transfer chamber Tc. At this time, the lower attachment prevention plate 82 moves up to the transfer position, and each of the movable bodies 7, 7 moves up synchronously to the transfer position protruding from the receiving recess 65 of the annular wall 6. Then, the substrate Sw supported by the robot hand 21 is transferred to each of the movable bodies 7, 7. As a result, the substrate Sw is supported at three points in the circumferential direction in a state where contact with the mounting plate portion 72, the driving plate portion 73, etc. can be reliably prevented, and only the bevel portion Sb is seated on each of the second inclined support surfaces 75a.

[0035] When the substrate Sw is supported by each of the movable bodies 7, 7, the robot hand 21 is withdrawn and then each of the movable bodies 7, 7 is moved downward in synchronization with each other. When the movable bodies 7, 7 exceed the height position where the first inclined support surface 64 and the second inclined support surface 75a are on the same horizontal plane, the remaining portion of the substrate Sw, except for the bevel portion Sb, located above each of the movable bodies 7, 7 is seated on the first inclined support surface 64, and the substrate Sw is transferred in a state where it is supported only by the first inclined support surface 64 of the annular wall 6. At this time, a predetermined gap exists between one surface of the substrate Sw and the upper surface of the base 5 or the upper surface of the driving plate portion 73. In this case, the gap is set as small as possible, for example, within a range of 0.5 mm or less, taking into consideration the size and warping of the substrate Sw. Also, each of the movable bodies 7 is immersed in the receiving recess 65 with a minute gap remaining.

[0036] When the substrate Sw is transferred to the annular wall 6, the gate valve Gv is closed and the lower protection plate 82 is lowered to the film formation position. As a result, the other surface of the substrate Sw except for the bevel portion Sb faces the film formation space Ps through the first opening 82b, and the upper part of the annular wall 6 is covered by the annular portion 82d of the lower protection plate 82, while the block body Ba faces the film formation space Ps through the second opening 82c of the lower protection plate 82. After the substrate Sw is supported, argon gas and nitrogen gas are introduced at flow rates of 10 to 20 sccm and 20 to 40 sccm, respectively (at this time, the pressure in the processing chamber Pc is 0.1 to 0.4 Pa), and at the same time, the sputtering power source 44 supplies pulse DC power of, for example, a frequency of 100 kHz and a pulse width of 2.0 μs (on duty 80%) in the range of 4 kW to 6 kW to the target 4. In addition, the sputtering power supply 44 can also input a high-frequency power of 13.56 MHz in the range of 4 kW to 6 kW. This forms a plasma atmosphere in the film formation space Ps, and the target 4 is sputtered. At this time, the upper surface of the base 5 is cooled to a predetermined temperature (22°C) by circulating a coolant through the coolant passage 5a of the base 5. Then, the reaction products of the sputter particles scattered from the target 4 by sputtering and the nitrogen gas are attached and deposited on the surface of the substrate Sw, so that a silicon nitride film is formed on the other surface of the substrate Sw. During film formation by the sputtering method, most of the bevel portion Sb is in contact with the first inclined support surface 64 of the annular wall 6, so that the substrate Sw does not become displaced. Moreover, since each movable body 7 is immersed in the receiving recess 65 with a small gap therebetween, not only the discharge leakage into the space between the lower surface of the substrate Sw and the upper surface of the base 5, but also the intrusion of the sputter particles and reaction products can be prevented.

[0037] When the film formation process is completed, the movable bodies 7, 7 are synchronously moved up to the delivery position, and a space into which the robot hand 21 can enter is formed between the substrate Sw and the upper surface of the substrate stage ST. In this state, the processed substrate Sw is delivered to the robot hand 21 in the reverse order to the above, and is transported from the processing chamber Pc to the load lock chamber Lc via the transport chamber Tc, and then returned to the cassette Kw by the atmospheric transport robot Rt.

[0038] Here, when a silicon nitride film is formed by the reactive sputtering method as described above, a reaction product is also formed on the surface of the target 4, so that stable film formation can be continued, and so-called dummy processing is periodically performed to clean the surface of the target 4 so that the reaction product on the surface of the target 4 does not become a source of new particles. In such a case, although not particularly shown or described, if a transport means is provided in the processing chamber Pc for supporting the shutter plate and transporting the shutter plate from a direction opposite to the transport direction of the substrate Sw (see FIG. 6) to a position where it can be delivered to the upper surfaces of the movable bodies 7, 7, the dummy processing can be easily performed without the need to transport the shutter plate from the atmosphere, which is advantageous.

[0039] According to the above, when the substrate Sw is transferred in the processing chamber Pc, the bevel portion Sb of the substrate Sw is supported at three points only by the second inclined support surface 75a of the movable body 7, 7, and the contact area with the substrate Sw is made as small as possible, so that the adhesion of fine particles (above a predetermined size) to the substrate Sw immediately after the film formation can be drastically reduced even if the film formation process is repeated. At this time, since the support protrusions 75 are made of a heat-resistant resin that is softer than the substrate Sw (i.e., has cushioning properties), it is effective in suppressing the generation of dust. Moreover, when the support protrusions 75 are deformed by repeatedly carrying the substrate Sw in and out, it is only necessary to replace the support protrusions 75 made of heat-resistant resin, which is advantageous. In addition, by providing the lower adhesion prevention plate 82 with the annular portion 82d that functions as a covering, the adhesion of sputtered particles to the annular wall 6 can be suppressed as much as possible. Therefore, it is possible to prevent the annular wall 6 from becoming a new particle generation source and causing fine particles (of a predetermined size or more) to adhere to the substrate Sw immediately after film formation. Moreover, it is advantageous that the substrate Sw can be easily transferred to and from the support protrusions 75 by the vacuum transfer robot Rv without interference.

[0040] Next, in order to confirm the above-mentioned effect, the following experiment was carried out using the above-mentioned vacuum processing system CM. In this experiment, a semiconductor wafer of φ300 mm was used as the substrate Sw, and a plurality of substrates Sw were sequentially transported to the processing chamber Pc according to the transportation of the substrate Sw between the cassette Kw and the substrate stage ST described above, and after a silicon nitride film was formed on the other surface of the substrate Sw, the substrate Sw on which the film had been formed was returned to the cassette Kw. As sputtering conditions, argon gas was introduced into the processing chamber Pc at a flow rate of 10 sccm and nitrogen gas was introduced into the processing chamber Pc at a flow rate of 30 sccm (the pressure in the processing chamber Pc at this time was about 0.4 Pa), and a silicon nitride film was formed on the silicon target 4 from the pulse DC power source Ps at a frequency of 100 kHz, a pulse width of 2.0 μs (on duty 80%), and an input power of 4 kW for 133 seconds. During the film formation by the reactive sputtering method, the upper surface of the base 5 was cooled to 22°C.

[0041] The number of particles on the other surface of the substrate Sw transported to the cassette Kw was confirmed. In this case, an existing particle counter was used to count the number of particles of 0.1 μm or more in a portion excluding a range of 0.5 mm from the outer periphery of the substrate Sw. First, as a comparative experiment, the substrate stage for back surface film formation of the above-mentioned conventional example was used, and the same experiment was performed. The number of particles of 0.1 μm or more was 8000 or more, and many particles were attached to the area outside the midpoint in the radial direction of the substrate Sw. On the other hand, in the invention experiment in which the bevel portion Sb of the substrate Sw was supported at three points by the second inclined support surface 75a of each support protrusion 75 of the movable body 7, the number of particles of 0.1 μm or more was 100 or less, and was also 100 or less even after repeated transport was performed 1000 times or more. It was confirmed from this experiment that the number of particles attached to the substrate Sw after film formation can be dramatically reduced.

[0042] Although the embodiment of the present invention has been described above with reference to the drawings, various modifications are possible without departing from the scope of the technical concept of the present invention. In the above embodiment, the vacuum processing apparatus has been described using a sputtering apparatus SM as an example, but the present invention can also be applied to other vacuum processing apparatuses such as a dry etching apparatus or a heat treatment apparatus. For example, in the case of a dry etching apparatus, the substrate Sw is held by the annular wall 6 with its front surface facing down, so that the front surface of the substrate Sw is prevented from coming into contact with the upper surface of the base 3 and being damaged when the back surface of the substrate Sw is subjected to dry etching processing. In addition, in the above embodiment, a pair (two) of movable bodies 7 is moved up and down as an example, but the number of movable bodies 7 is not limited as long as the substrate Sw can be lifted. Furthermore, in the above embodiment, a silicon target 4 is used and a silicon nitride film is formed by reactive sputtering as an example, but the present invention can also be applied to a case where a silicon nitride target is sputtered to form a silicon nitride film, or a metal target is sputtered to form a metal film. [Explanation of symbols]

[0043] ST...substrate stage, 5...base, 6...annular wall, 64...first inclined support surface, 65...receiving recess, 7...movable body, 74...actuator (driving body), 75...support protrusion, 75a...second inclined support surface, Sw...substrate (semiconductor wafer), Sb...outer peripheral edge portion (bevel portion) of substrate, Pc...processing chamber (vacuum chamber), 4...target (constituent element of film forming means for forming film by sputtering method), 8...adhesion protection plate, 82...lower adhesion protection plate (movable part), 82c...opening, 82e...annular portion (constituting the covering), Ba...block body.

Claims

1. A substrate stage is disposed in a vacuum chamber in which a predetermined vacuum process is performed on a substrate to be processed, and on which the substrate to be processed is placed, A processing apparatus comprising: a base; and an annular wall supporting a lower surface outer periphery of a substrate to be processed with a gap therebetween from an upper surface of the base, a first inclined support surface is formed on an inner edge of an upper surface of the annular wall, the first inclined support surface being inclined downward in a radially inward direction and on which an outer circumferential edge of a lower surface of a substrate to be processed is seated, and a plurality of receiving recesses are formed at intervals in a circumferential direction in the inner wall of the annular wall and recessed radially outward; The receiving recesses may further include movable bodies that are accommodated in the receiving recesses, and a driving body that moves the movable bodies up and down in synchronization with each other. A substrate stage characterized in that a support protrusion having a second inclined support surface that slopes downward radially inward is provided on the upper surface of each movable body, such that the second inclined support surface of each support protrusion can support the outer circumferential edge of the lower surface of the substrate to be processed at three or more points in the circumferential direction, and the substrate to be processed is transferred to the first inclined support surface by downward movement of each movable body from a state in which the substrate to be processed is supported by each support protrusion.

2. 2. A substrate stage according to claim 1, wherein the support protrusions are made of a heat-resistant resin and are detachably attached to the upper surface of each of the movable bodies.

3. 3. A vacuum processing apparatus comprising: a vacuum chamber including the substrate stage according to claim 1; and a film forming means for performing a film forming process on an upper surface of the substrate supported by the substrate stage in a vacuum atmosphere in the vacuum chamber, The vacuum film forming apparatus further comprises a cover ring that covers an upper surface of the annular wall with a vertical gap therebetween.

4. 4. The vacuum deposition apparatus according to claim 3, further comprising an adhesion prevention plate disposed within the vacuum chamber, the adhesion prevention plate being positioned around the annular wall and having a movable part that can move up and down, wherein the cover ring is held by the movable part.

5. 5. The vacuum film forming apparatus according to claim 4, wherein the film forming means is a sputtering cathode provided in the vacuum chamber facing the substrate stage, and a conductive cylindrical block body is provided around the substrate stage so as to face the plasma atmosphere formed in the vacuum chamber, 2. A vacuum processing apparatus comprising: a block body having a movable portion disposed above the block body, the movable portion having an opening ratio of 50% or more;

6. 6. The vacuum film forming apparatus according to claim 5, wherein the substrate is transported in one direction around the substrate stage while the movable body is moved upward, A vacuum processing apparatus characterized in that a transport means is provided within the vacuum chamber for supporting a shutter plate and transporting the shutter plate from a direction opposite to the transport direction of the substrate to be processed to a position where it can be handed over to the upper surface of each movable body.

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