Robot hand for conveyance

Abstract

To provide a robot hand 21 provided in a vacuum conveyance robot Rv for conveying a substrate Sw for supporting the substrate Sw while the substrate Sw is being mounted on the robot hand, the robot hand allowing a reliable support and conveyance while the lower surface of the substrate is not in contact with anything.MEANS FOR SOLVING THE PROBLEM: The present invention includes: a ridge 25 located on the same circle with the same specific diameter as that of the substrate on the upper surface of the robot hand 21 and extending in the shape of a band and protruding to the above; and at least two supporting protrusions 27 protruding to the above, in a circumferential direction at intervals. The ridge 25 and the supporting protrusions 27 each have inclined supporting surfaces 25a and 27b inclined downward to the inner side of the radial direction, a lower surface outside peripheral part Sb of the substrate Sw being seated on the inclined supporting surfaces, and a step to the above is provided in the outside periphery of the inclined supporting surface.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a transport robot hand that is provided on a transport robot for transporting a substrate to be processed and supports the substrate to be processed in a placed state. [Background technology]

[0002] As an example of this type of robot hand for transporting substrates, the one described in Patent Document 1 is known. In this robot hand, a first seating surface on which the outer peripheral edge of the lower surface of a semiconductor wafer serving as a substrate to be processed sits is provided on the upper surface of the robot hand, and an upward step is formed on the outer periphery of this first seating surface. In addition, a second seating surface that is inclined downward toward the center of the semiconductor wafer is provided on the upper surface of the robot hand away from the outer peripheral edge of the lower surface of the substrate to be processed, and the second seating surface is inclined downward toward the center of the semiconductor wafer so that the underside of the semiconductor wafer sits on it when the semiconductor wafer is warped downward in a concave shape.

[0003] Incidentally, semiconductor wafers usually have warpage. When a predetermined thin film is formed on one side of the semiconductor wafer (i.e., the side on which the device structure is formed) by a film formation process, the amount of warpage may increase due to the stress of the formed thin film (when multiple thin films are stacked, the amount of warpage may become even greater). For this reason, it is generally known to form a predetermined thin film (e.g., a silicon nitride film) on the other side of the semiconductor wafer to minimize the warpage of the silicon wafer.

[0004] When a predetermined thin film is to be formed on the other side of the semiconductor wafer, the other side of the semiconductor wafer is supported by a robot hand in a position where it is received upward and transported. In the above-mentioned conventional example, if the semiconductor wafer is warped downward in a concave shape, the lower surface of the semiconductor wafer (one surface forming the device structure) comes into contact with the second seating surface, and there is a risk that the lower surface of the semiconductor wafer may be damaged by vibration or the like during transportation. In such a case, it is possible to attach a protective sheet to one side of the silicon wafer, but this increases the number of manufacturing steps and leads to increased costs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5033886 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above, an object of the present invention is to provide a robot hand for transporting a substrate that can reliably support and transport the substrate without its underside coming into contact with anything when transporting the substrate. [Means for solving the problem]

[0007] In order to solve the above problems, the transport robot hand of the present invention is provided in a transport robot for transporting a substrate to be processed and supports the substrate to be processed in a placed state, and is characterized in that the robot hand has, on the upper surface of the robot hand, a protrusion extending in a strip shape and protruding upward, and at least two support protrusions protruding upward, which are positioned on the same circumference having a predetermined diameter equivalent to that of the substrate to be processed, and are spaced apart in the circumferential direction, the protrusion and the support protrusion each have an inclined support surface that is inclined downward toward the inside in the radial direction and on which the outer periphery of the substrate to be processed rests, and an upward step is provided on the outer periphery of the inclined support surface. In this case, a configuration can be adopted in which the inclined support surface is inclined at an angle of 4 degrees to 30 degrees with respect to the surface of the robot hand.

[0008] According to the present invention, since the substrate is supported with only the outer peripheral portion of the lower surface of the substrate partially seated on the inclined support surface of the protrusion and the support protrusion, even if the substrate is warped downward in a concave shape, the substrate can be reliably supported without the lower surface of the substrate being in contact with the upper surface of the robot hand. During transportation, a part of the outer peripheral portion of the substrate is in line contact with the inclined support surface of the relatively long protrusion, and at least two points of the remaining outer peripheral edge are in contact with the inclined support surface of the support protrusion in the circumferential direction, so that the substrate is prevented from being displaced due to frictional resistance, and stable transportation is possible. Furthermore, since there is an upward step on the outer periphery of the inclined support surface, for example, even if the substrate moves up the inclined support surface due to the inertial force of the robot hand when the robot hand stops moving, the momentum is reduced by contacting the step, and the substrate is prevented from falling off the robot hand. Here, when the substrate to be processed is a semiconductor wafer having a beveled outer peripheral edge, if the inclined support surface is inclined at an angle of 4 to 30 degrees relative to the surface of the robot hand, even if the semiconductor wafer is warped concavely downward, the substrate to be processed can be supported with a small gap remaining to reliably prevent contact with the upper surface of the robot hand and with only the bevel portion seated on the inclined support surface between the protrusion and the support protrusion.

[0009] In the present invention, it is preferable that the protrusions and the support protrusions are made of a heat-resistant resin and are detachably attached to the upper surface of the robot hand. If the protrusions and the support protrusions are made of a heat-resistant resin that is softer than the substrate to be processed (i.e., has cushioning properties), it is effective to suppress the generation of dust, for example, when the substrate to be processed is transferred to the robot hand or when it is transported. Furthermore, if the protrusions or the support protrusions become deformed due to repeated transport of the substrate to be processed, it is advantageous to only replace the protrusions or the support protrusions made of the heat-resistant resin. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a schematic configuration of a vacuum processing system including a substrate stage 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 an oblique view of the robot hand of this embodiment, 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 protrusions. [Figure 4] FIG. 2 is a cross-sectional view showing a sputtering apparatus at a film forming 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

[0011] Below, with reference to the drawings, an embodiment will be described in which the "substrate to be processed" is a semiconductor wafer (hereinafter referred to as "substrate Sw") having a diameter of 300 mm, and its "outer peripheral 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 transport robot hand of the present invention is applied to a vacuum transport robot provided in a cluster tool type vacuum processing system.

[0012] 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 any one of the processing chambers Pc constitutes a vacuum chamber of a sputtering apparatus as a vacuum processing apparatus including a substrate stage ST. 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.

[0013] 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.

[0014] 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 of this embodiment at the tip thereof for supporting the substrate Sw in a placed state, and two concentric rotating shafts 23a, 23b for rotating and driving each robot arm 22. The robot arm 22 rotates or expands and contracts in 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 and 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.

[0015] 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.

[0016] 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.

[0017] According to the 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 the contact with the steps 25b, 27b, and the substrate Sw can be prevented from falling off the robot hand 21. Moreover, since the ridges 25 and the support projections 27 are detachably attached, when the ridges 25 or the support projections 27 are deformed by repeated transport of the substrate Sw, it is advantageous to replace only the ridges 25 or the support projections 27. In each of the processing chambers Pc connected to the transport chamber Tc via the 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. Then, in any one of the processing chambers Pc, a silicon nitride film is formed on the other side of the substrate Sw by sputtering. This will be described below with reference to Figs. 4 to 8.

[0018] 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 top 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 top 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. A substrate stage ST is disposed at the bottom of the processing chamber Pc, facing the target 4.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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, pulse DC power with a frequency of 100 kHz and a pulse width of 2.0 μs (on duty 80%) is input to the target 4 by the sputtering power source 44 in the range of 4 kW to 6 kW. It is also possible to input a high frequency power of 13.56 MHz in the range of 4 kW to 6 kW from the sputtering power supply 44. 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, a reaction product of the sputtered particles scattered from the target 4 by sputtering and the nitrogen gas is attached and deposited on the surface of the substrate Sw, and a silicon nitride film is formed on the other surface of the substrate Sw.

[0032] During film formation by sputtering, 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, it is possible to prevent not only 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 sputtered particles and reaction products. 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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 the portion excluding the range of 3.0 mm from the outer periphery of the substrate Sw. First, as a comparative experiment, the robot hand of the above conventional example made of silicon carbide was used as the robot hand, and the number of particles after 430 repeated transports was confirmed. According to this, the number of particles of 0.1 μm or more in the portion excluding the range of 3.0 mm from the outer periphery of the substrate Sw was 700 or more, and when the in-plane distribution of the particles was confirmed, many particles were attached to the area outside the midpoint in the radial direction of the substrate Sw.

[0037] Next, the robot hand was changed to that described in the above embodiment (provided with the protrusions 25 and support protrusions 27 having the inclined support surfaces 25a, 27a), and the number of particles after 430 repeated transfers was confirmed (Invention Experiment 1). However, in Inventive Experiment 1, the protrusions 25 and support protrusions 27 were made of silicon carbide, the same material as the robot hand 21. This made it possible to reduce the number of particles of 0.1 μm or more to 180 or less, and it was confirmed that the number of particles could be significantly reduced by simply changing the support form of the substrate Sw in the robot hand 21 (i.e., the form in which the substrate Sw is supported at four circumferential points by the inclined support surfaces 25a, 27a of the protrusions 25 and support protrusions 27).

[0038] Next, the protrusions 25 and support protrusions 27 of the robot hand used in the above invention experiment 1 were changed to a fluorine-based heat-resistant resin, and the number of particles after 430 repeated transfers was confirmed (invention experiment 2). According to this, the number of particles of 0.1 μm or more could be reduced to 50 or less, and it was confirmed that the number of particles can be dramatically reduced by constructing the protrusions 25 and support protrusions 27 from heat-resistant resin. It was also confirmed that the number of particles could be maintained at 50 or less after 1,043 repeated transfers.

[0039] 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 5 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]

[0040] Rv...vacuum transfer robot, 21...robot hand, 21a...base end, 21b...finger portion, 25...rib, 27...support protrusion, 25a, 27a...inclined support surface, Sw...substrate (semiconductor wafer), Sb...outer peripheral edge portion (bevel portion) of substrate.

Claims

1. A robot hand for transporting a substrate to be processed, which is provided to a transport robot for transporting a substrate to be processed and supports the substrate to be processed in a placed state, a protrusion extending in a band shape and protruding upward, and at least two support projections protruding upward, are provided on an upper surface of the robot hand, the protrusions being positioned on the same circumference having a predetermined diameter equivalent to that of the substrate to be processed, and the support projections are provided at intervals in the circumferential direction; A robot hand for transport, characterized in that the protrusions and the support projections each have an inclined support surface that slopes downward radially inwardly on which the outer peripheral edge of the substrate to be processed rests, and an upward step is provided on the outer periphery of the inclined support surface.

2. 2. The robot hand for transportation according to claim 1, wherein the inclined support surface is inclined at an angle of 4 degrees to 30 degrees with respect to the surface of the robot hand.

3. 3. The robot hand for transportation according to claim 1, wherein the ridges and the support protrusions are made of a heat-resistant resin and are detachably attached to an upper surface of the robot hand.

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