Transport robot

Abstract

To provide a transfer robot that prevents particles from being emitted to the outside of each arm and can change a transfer chamber from a vacuum state to an atmospheric pressure state in a short time.SOLUTION: A transfer robot B1 includes a fixture base 1, an elevating base 2, a hollow arm 3 rotatably supported around a shaft O1 with respect to the elevating base 2, a hollow arm 4 in which a shaft portion 44 is rotatably supported around a shaft O2 with respect to the arm 3, a hand 5 in which the shaft portion 51 is rotatably supported around a shaft O3 with respect to the arm 4, a drive mechanism 6 that rotates the shaft portions 44 and 51, dustproof seals 36 and 46 placed between the arm 3 and the shaft 44 and between the arm 4 and the shaft 51, dustproof filters 312 and 412 that can ventilate the inside and outside of the arms 3 and 4, and pressure actuated valves 7 and 8 provided on the arms 3 and 4 that open, and close when the inside has lower pressure than the outside and the pressure difference between the inside and the outside is greater than or equal to a predetermined value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a transfer robot, and more particularly to a transfer robot for transferring thin plate-like workpieces such as wafers in a vacuum environment in semiconductor manufacturing and the like. [Background technology]

[0002] In fields such as semiconductor manufacturing, a transfer robot for transferring a workpiece such as a wafer is used. The workpiece transfer device is used, for example, to transfer the workpiece between a load port in which the wafer is accommodated and a process chamber.

[0003] A transport robot for transporting such thin plate-like workpieces is disclosed, for example, in Patent Document 1 below. This transport robot includes a fixed base, a lift base that is supported by the fixed base and moves up and down, a first arm, a second arm, and a hand that are each supported on the lift base so as to be rotatable about a predetermined axis, and a drive mechanism that drives and rotates the first arm, the second arm, and the hand. The transport robot is disposed in a transport room such as a transfer chamber, and transports the workpieces in a vacuum environment.

[0004] The first arm and the second arm are hollow, and a drive unit using a belt or the like is disposed inside the first arm and the second arm. Therefore, dust (particles) are generated inside the arm due to wear of the drive unit. In order to prevent the particles inside the arm from being released to the outside (transfer chamber), a dustproof seal such as a magnetic fluid seal is provided on the rotating part of the arm. Also, when the inside of the transfer chamber (outside of the arm) is in a vacuum state, in order to prevent the dustproof seal from being damaged by the pressure difference between the inside and outside of the arm, for example, an air vent is provided in the arm and a dustproof filter is provided to block the air vent. This allows ventilation between the inside and outside of the arm, eliminating the pressure difference between the inside and outside of the arm, and prevents the particles inside the arm from being released to the outside.

[0005] When the transfer chamber in which the transfer robot of the above configuration is placed is released from a vacuum state to atmospheric pressure, the inside of the arm also goes from a vacuum state to atmospheric pressure due to ventilation through the dustproof filter. On the other hand, since the dustproof seal has a relatively small ventilation amount, if the transfer chamber is released from a vacuum state to atmospheric pressure all at once in a short time, for example, the pressure difference between the inside and outside of the arm increases temporarily. If the pressure difference between the inside and outside of the arm exceeds the pressure resistance of the dustproof seal, a problem may occur in which the dustproofness of the dustproof seal is impaired. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2003-188231 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention was devised under these circumstances, and its main objective is to provide a transport robot that can prevent particles from being released outside each arm and can change the transport chamber from a vacuum state to atmospheric pressure in a short period of time. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention employs the following technical means.

[0009] A transport robot provided according to a first aspect of the present invention includes an attachment base, a hollow first arm having one end supported to be rotatable about a first vertical axis relative to the attachment base, a hollow second arm having a first shaft portion disposed at one end, the first shaft portion being supported to be rotatable about a second vertical axis relative to the other end of the first arm, a hand having a second shaft portion being supported to be rotatable about a third vertical axis relative to the other end of the second arm, and a drive mechanism for driving and rotating the first shaft portion and the second shaft portion. the first arm and the first shaft portion, and the second arm and the second shaft portion; a dust filter provided in each of the first arm and the second arm to allow ventilation between the internal space of the arm and the outside; and a first pressure-operated valve and a second pressure-operated valve provided in the first arm and the second arm to open so that the internal space communicates with the outside when the internal space is at a lower pressure than the outside and the pressure difference between the internal space and the outside is equal to or greater than a predetermined value, and to close otherwise.

[0010] In a preferred embodiment, the first arm and the second arm are formed with a first opening and a second opening corresponding to the first pressure-operated valve and the second pressure-operated valve, respectively, and the first pressure-operated valve and the second pressure-operated valve have a first valve body and a second valve body that block the first opening and the second opening in a closed state and are displaced inward of the first arm and the second arm in an open state.

[0011] In a preferred embodiment, the first arm and the second arm each include an upper wall and a lower wall that face each other in the vertical direction, and a side wall connected to both the upper wall and the lower wall, and the first opening and the second opening are formed in the lower wall.

[0012] In a preferred embodiment, the drive mechanism includes a first endless belt that is disposed inside the first arm and rotates the first shaft portion, and a second endless belt that is disposed inside the second arm and rotates the second shaft portion, and the first valve body and the second valve body are disposed inside the first endless belt and the second endless belt in a planar view.

[0013] A workpiece transport system provided by a second aspect of the present invention comprises a transport robot relating to the first aspect of the present invention, a transport chamber in which the transport robot is disposed, a processing chamber provided adjacent to the transport chamber for performing a predetermined processing on the workpiece, and a switching means for switching the transport chamber between atmospheric pressure and vacuum conditions. Effect of the Invention

[0014] In the transport robot according to the present invention, dust-proof seals are arranged between the hollow first arm and the first shaft, and between the hollow second arm and the second shaft. The first arm and the second arm are provided with dust-proof filters that allow ventilation between the internal space of the arm and the outside. The first arm and the second arm are provided with a first pressure-operated valve and a second pressure-operated valve. The first pressure-operated valve and the second pressure-operated valve open so that the internal space of the arm communicates with the outside when the internal space of the arm is at a lower pressure than the outside and the pressure difference between the internal space and the outside is equal to or greater than a predetermined value. With this configuration, even if the transport chamber in which the transport robot is arranged is suddenly released from a vacuum state to an atmospheric pressure state in a short time, the dust-proof properties of the dust-proof seal can be prevented from being impaired.

[0015] Other features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0016] [Figure 1] 1 is a plan view showing an example of a workpiece transport system including a transport robot according to the present invention; [Diagram 2]2 is a vertical sectional view showing a schematic structure of the transport robot shown in FIG. [Diagram 3] 2 is a plan view for explaining the operation of the transport robot shown in FIG. [Figure 4] FIG. 3 is an enlarged view of a main part of FIG. 2. [Diagram 5] FIG. 3 is an enlarged view of a main part of FIG. 2. [Figure 6] FIG. 4 is a plan view illustrating the arrangement of the first pressure operated valve and the second pressure operated valve. [Figure 7] FIG. 11 is a plan view showing another example of the workpiece transport system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0018] 1 shows an example of a workpiece transport system equipped with a transport robot according to the present invention. The workpiece transport system A1 of this embodiment includes a transport chamber 91, a processing chamber 92, and a transport robot B1, and is configured to transport a thin plate-like workpiece W, such as a circular silicon wafer for semiconductor manufacturing.

[0019] The transfer chamber 91 has a predetermined internal space, and the transfer robot B1 is disposed in the transfer chamber 91. In this embodiment, the work transfer system A1 includes two transfer chambers 91, and the transfer robot B1 is disposed in each transfer chamber 91. The processing chamber 92 is for performing a predetermined process on the thin plate-like workpiece W, and is configured, for example, by a vacuum chamber that processes the thin plate-like workpiece W in a vacuum environment. The processing chamber 92 is disposed adjacent to both of the two transfer chambers 91. An opening / closing door 99 is provided between the processing chamber 92 and each transfer chamber 91. When the opening / closing door 99 between the processing chamber 92 and the transfer chamber 91 is opened, the processing chamber 92 and the transfer chamber 91 communicate with each other, and the transfer robot B1 can carry the thin plate-like workpiece W into and out of the processing chamber 92. In addition, an opening / closing door 99 is provided on the opposite side of the processing chamber 92 in each transfer chamber 91.

[0020] In the configuration shown in FIG. 1, when a workpiece is transported, for example, a transport robot B1 arranged in the transport chamber 91 at the top in the figure transports an unprocessed thin plate-shaped workpiece W from the outside through an opening and closing door 99 at the top end in the figure. Next, the opening and closing door 99 at the top end in the figure is closed, the inside of the transport chamber 91 is made into a vacuum state, and the opening and closing door 99 between the processing chamber 92 and the transport chamber 91 is opened, and the unprocessed thin plate-shaped workpiece W is transported to the processing chamber 92. The transport robot B1 arranged in the transport chamber 91 at the left side in the figure transports the processed thin plate-shaped workpiece W from the processing chamber 92. Next, the opening and closing door 99 between the processing chamber 92 and the transport chamber 91 is closed, the inside of the transport chamber 91 is switched from a vacuum state to an atmospheric pressure state, and the opening and closing door 99 at the left end in the figure is opened, and the processed thin plate-shaped workpiece W is transported to the outside through the opening and closing door 99. In the configuration shown in FIG. 1, the transport chamber 91 at the top in the figure serves as both a load lock chamber and a transfer chamber. The transfer chamber 91 on the left side of the drawing serves as both an unload lock chamber and a transfer chamber.

[0021] As shown in FIG. 2, two pipes L1 and L2 are connected to the transfer chamber 91. One of the pipes, L1, is provided with a vent valve 901. The end of the pipe L1 is open to the atmosphere, and when the vent valve 901 is open, the atmosphere can be introduced into the transfer chamber 91 through the pipe L1. The other pipe, L2, is provided with a vacuum valve 902 and a vacuum pump 903. When the vent valve 901 is closed and the vacuum valve 902 is opened, the air in the transfer chamber 91 is discharged through the pipe L2. This reduces the pressure in the transfer chamber 91, and the transfer chamber 91 is in a vacuum state. When the vent valve 901 is opened and the vacuum valve 902 is closed, the atmosphere is introduced into the transfer chamber 91 through the pipe L1, and the transfer chamber 91 is in an atmospheric pressure state. In this way, the transfer chamber 91 can be switched between an atmospheric pressure state and a vacuum state. In this embodiment, the vent valve 901, the vacuum valve 902, and the vacuum pump 903 constitute a switching means as referred to in the present invention.

[0022] As shown in FIG. 2, the transfer robot B1 includes a fixed base 1, a lift base 2, a first arm 3, a second arm 4, a hand 5, a drive mechanism 6, a first pressure operated valve 7, and a second pressure operated valve 8.

[0023] The fixed base 1 is configured as a housing having a substantially cylindrical outer shape, and has a ceiling wall 11 extending radially outward at its upper end. This ceiling wall 11 is fixed to the bottom wall of the transfer chamber 91. The lifting base 2 is supported so as to be movable up and down relative to the fixed base 1. Although detailed illustrations are omitted, the lifting base 2 has a lifting mechanism for lifting and lowering the lifting base 2 relative to the fixed base 1 and a drive source (such as a motor) for providing power to the lifting mechanism disposed inside the fixed base 1, and the lifting base 2 is lifted and lowered by the drive source.

[0024] The first arm 3 is supported by the lift base 2 in a position in which the longitudinal direction is horizontal. The first arm 3 includes an upper wall 31 and a lower wall 32 that face each other in the vertical direction, and a side wall 33 that is connected to both the upper wall 31 and the lower wall 32, and is hollow with an internal space surrounded by the upper wall 31, the lower wall 32, and the side wall 33. Although detailed illustrations are omitted, an opening is formed in the lower wall 32 at one end (the left end in FIG. 2) of the first arm 3, and the first arm 3 has an extension extending downward from the periphery of the opening. The extension is rotatable around the first vertical axis O1. With this configuration, the first arm 3 is supported rotatably around the first vertical axis O1 with respect to the fixed base 1 or the lift base 2. Although detailed illustration is omitted, a driving source (motor, etc.) for rotating the first arm 3 is arranged inside the fixed base 1, and the first arm 3 is rotated around the first vertical axis O1 by the driving of the driving source. A rotating shaft 21 extending upward from the lift base 2 side is inserted into the opening of the lower wall 32. The rotating shaft 21 is rotatable around the first vertical axis O1. In the example shown in FIG. 2, a bearing is interposed between the lower wall 32 (first arm 3) and the rotating shaft 21. In this embodiment, the transport robot B1 has a lift mechanism, but the transport robot B1 may be configured not to have a lift mechanism. When the transport robot B1 does not have a lift mechanism, the first arm 3 is rotatably supported on the fixed base 1 or a pedestal base (not shown) for height adjustment in a posture in which the longitudinal direction is horizontal. Here, the lifting base 2 in the case of the transport robot B1 having a lifting mechanism, and the fixed base 1 or the pedestal base (not shown) in the case of the transport robot B1 not having a lifting mechanism, are collectively referred to as the mounting base.

[0025] An opening is formed in upper wall 31 at the other end (the right end in FIG. 2) of first arm 3. A fixed shaft 35 is provided in lower wall 32 at the other end of first arm 3. Fixed shaft 35 has second vertical axis O2 as its central axis and extends upward through the opening in upper wall 31.

[0026] The second arm 4 is supported by the first arm 3 in a position in which the longitudinal direction is horizontal. The second arm 4 includes an upper wall 41 and a lower wall 42 that face each other in the vertical direction, and a side wall 43 that is connected to both the upper wall 41 and the lower wall 42, and is hollow with an internal space surrounded by the upper wall 41, the lower wall 42, and the side wall 43. An opening is formed in the lower wall 42 at one end (the right end in FIG. 2) of the second arm 4, and the second arm 4 has a cylindrical first shaft portion 44 that extends downward from the periphery of this opening. The first shaft portion 44 is fitted onto the fixed shaft 35 of the first arm 3, and a bearing (not shown) is interposed between the fixed shaft 35 and the first shaft portion 44. As a result, the first shaft portion 44 is rotatable around the second vertical axis O2. With this configuration, one end of the second arm 4 is supported by the other end of the first arm 3 so as to be rotatable around the second vertical axis O2. The fixed shaft 35 of the first arm 3 passes through the opening in the lower wall 42 and extends into the inside of the second arm 4 .

[0027] An opening is formed in upper wall 41 at the other end (left end in FIG. 2) of second arm 4. A fixed shaft 45 is provided on lower wall 42 at the other end of second arm 4. Fixed shaft 45 has third vertical axis O3 as its central axis and extends upward through the opening in upper wall 41.

[0028] As shown in FIG. 1 and other figures, the hand 5 has a bifurcated fork-like tip and is supported by the second arm 4 in a horizontal position. The hand 5 is for placing and holding a thin plate-like workpiece W of a predetermined size, such as a circular silicon wafer. As shown in FIG. 2, the hand 5 has a second shaft portion 51 extending downward from the base end of the hand 5. The second shaft portion 51 is fitted onto the fixed shaft 45 of the second arm 4, and a bearing (not shown) is interposed between the fixed shaft 45 and the second shaft portion 51. This allows the second shaft portion 51 to rotate around the third vertical axis O3. With this configuration, the hand 5 is supported by the other end of the second arm 4 so as to be rotatable around the third vertical axis O3.

[0029] The driving mechanism 6 rotates the second arm 4 (first shaft portion 44) and the hand 5 (second shaft portion 51). As shown in FIG. 2, in this embodiment, the driving mechanism 6 includes a pulley 61, a pulley 62, a first endless belt 63, a pulley 64, a pulley 65, and a second endless belt 66. The pulley 61 is connected to the upper end of the rotating shaft 21 and is rotatable around the first vertical axis O1. The pulley 62 is connected to the lower end of the first shaft portion 44 and is fitted to the fixed shaft 35 and is rotatable around the second vertical axis O2. The first endless belt 63 is wound around the pulley 61 and the pulley 62. The first endless belt 63 is disposed inside the first arm 3 and rotates the pulley 62 and the first shaft portion 44 connected thereto. The pulley 64 is connected to the upper end of the fixed shaft 35. The pulley 65 is connected to the lower end of the second shaft portion 51 and fitted onto the fixed shaft 45, and is rotatable about the third vertical axis O3. The second endless belt 66 is wound around the pulleys 64 and 65. The second endless belt 66 is disposed inside the second arm 4, and rotates the pulley 62 and the first shaft portion 44 connected thereto, and rotates the pulley 65 and the second shaft portion 51 connected thereto.

[0030] In the configuration including the above-mentioned drive mechanism 6 (pulley 61, pulley 62, first endless belt 63, pulley 64, pulley 65, and second endless belt 66), as shown in FIG. 3, when the first arm 3 is rotated around the first vertical axis O1, the second arm 4 rotates around the second vertical axis O2 according to the outer diameter ratio of the pulleys 61 and 62. In addition, with the rotation of the second arm 4, the hand 5 rotates around the third vertical axis O3 according to the outer diameter ratio of the pulleys 64 and 65. In this embodiment, the hand 5 always faces the same direction regardless of the rotation of the first arm 3 and the second arm 4. As a result, the hand 5 is moved linearly in the horizontal direction, and the thin plate-like workpiece W can be carried in and out of the processing chamber 92 shown in FIG. 1.

[0031] In this embodiment, dustproof seals 34, 36, 46 are arranged between the first arm 3 (lower wall 32) and the rotating shaft 21, between the first arm 3 (upper wall 31) and the first shaft 44, and between the second arm 4 (upper wall 41) and the second shaft 51. Inside the first arm 3 and the second arm 4, dust (particles) are generated due to wear of each part such as the driving mechanism 6. The dustproof seals 34, 36, 46 prevent the particles generated inside the first arm 3 and the second arm 4 from being released to the outside (into the transfer chamber 91). As the dustproof seals 34, 36, 46, for example, a magnetic fluid seal having a magnetic fluid can be mentioned, but the type of the dustproof seals 34, 36, 46 is not particularly limited. In the example shown in FIG. 2, a bearing interposed between the lower wall 32 and the rotating shaft 21 is adjacent to the dustproof seal 34. If the bearing prevents particles from being released to the outside, the dust seal 34 does not necessarily have to be provided.

[0032] In this embodiment, an air vent 311 is formed at an appropriate position in the upper wall 31 of the first arm 3. In addition, a dust filter 312 that blocks the air vent 311 is provided in the upper wall 31. The dust filter 312 is, for example, a HEPA filter (High Efficiency Particulate Air Filter) or a ULPA filter (Ultra Low Penetration Air Filter). The dust filter 312 prevents dust (particles) inside the first arm 3 from being discharged to the outside (inside the transfer chamber 91) while allowing ventilation between the internal space of the first arm 3 and the outside. When the dust filter 312 is a HEPA filter or a ULPA filter, the amount of ventilation through the dust filter 312 is relatively small. Furthermore, in this embodiment, a first opening 321 is formed at an appropriate position in the lower wall 32. The significance of the first opening 321 will be described later.

[0033] An air vent 411 is formed at an appropriate position in the upper wall 41 of the second arm 4, and a dust filter 412 is provided to close the air vent 411. The dust filter 312 is, for example, a HEPA filter or a ULPA filter, and prevents particles inside the second arm 4 from being released to the outside (into the transfer chamber 91) while allowing air to flow between the internal space of the second arm 4 and the outside. When the dust filter 412 is a HEPA filter or a ULPA filter, the amount of air passing through the dust filter 412 is relatively small. Furthermore, in this embodiment, a second opening 421 is formed at an appropriate position in the lower wall 42. The significance of this second opening 421 will be described later.

[0034] The first pressure operated valve 7 is provided in the first arm 3, and performs an opening operation when a predetermined pressure condition is met between the internal space of the first arm 3 and the outside. As shown in Fig. 4, in this embodiment, the first pressure operated valve 7 has a first valve body 71, a seal member 72, a rotating shaft 73, and a biasing member 74.

[0035] The first valve body 71 is a swing valve that can rotate freely around a rotation shaft 73. In FIG. 4, the first valve body 71 is shown in an open state by a solid line, and the first valve body 71 is shown in a closed state by a virtual line. The first valve body 71 is disposed at a position corresponding to a first opening 321 formed in the lower wall 32, and displaces toward the inside of the first arm 3 in the open state. In the open state of the first valve body 71, the internal space of the first arm 3 communicates with the outside (inside the transfer chamber 91) through the first opening 321. The seal member 72 is disposed near the outer periphery of the lower surface of the first valve body 71. The biasing member 74 applies a biasing force in a direction in which the first valve body 71 closes, and is constituted by, for example, a compression spring interposed between the upper wall 31 and the first valve body 71. When the first valve body 71 is in a closed state, the seal member 72 is in close contact with the outer periphery of the first opening 321 in the lower wall 32, and the first opening 321 is closed.

[0036] The first pressure operated valve 7 having the above configuration opens when the pressure in the internal space of the first arm 3 is lower than the external pressure and the pressure difference between the internal space of the first arm 3 and the outside is equal to or greater than a predetermined value. A pressing force acts on the first arm 3 from the outside to the inside, and the first valve body 71 moves toward the inside of the first arm 3 against its own weight and the biasing force of the biasing member 74. Then, as shown by the dashed arrow in FIG. 4, gas outside the first arm 3 (inside the transfer chamber 91) flows into the inside of the first arm 3 through the first opening 321. The above predetermined value (pressure difference between the internal space of the first arm 3 and the outside when the first valve body 71 opens) is set to a value slightly lower than the pressure resistance of the dustproof seals 34, 36.

[0037] The second pressure operated valve 8 is provided in the second arm 4, and performs an opening operation when the pressure conditions between the internal space of the second arm 4 and the outside are predetermined. As shown in Fig. 5, in this embodiment, the second pressure operated valve 8 has a second valve body 81, a seal member 82, a cylindrical portion 83, and a biasing member 84.

[0038] The cylindrical portion 83 extends with the vertical direction as its axis, and the second valve body 81 is a movable valve that can move up and down inside the cylindrical portion 83. A plurality of through holes 831 are formed in the vertical middle of the cylindrical portion 83. In FIG. 5, the second valve body 81 is shown in an open state by a solid line, and the second valve body 81 is shown in a closed state by a virtual line. The second valve body 81 is disposed at a position corresponding to the second opening 421 formed in the lower wall 42, and displaces toward the inside of the second arm 4 in the open state. In the open state of the second valve body 81, the internal space of the second arm 4 communicates with the outside (inside the transfer chamber 91) via the first opening 321 and the plurality of through holes 831. The seal member 82 is disposed near the outer periphery of the lower surface of the second valve body 81. The biasing member 84 applies a biasing force in a direction in which the second valve body 81 closes, and is constituted by, for example, a compression spring interposed between the upper wall 41 and the second valve body 81. When the second valve body 81 is in a closed state, the seal member 82 is in close contact with the outer periphery of the second opening 421 in the lower wall 42, and the second opening 421 is closed.

[0039] The second pressure actuated valve 8 having the above configuration opens when the pressure in the internal space of the second arm 4 is lower than the external pressure and the pressure difference between the internal space of the second arm 4 and the outside is equal to or greater than a predetermined value. A pressing force acts on the second arm 4 from the outside to the inside of the second arm 4, and the second valve body 81 moves toward the inside of the second arm 4 against its own weight and the biasing force of the biasing member 84. Then, as shown by the dashed arrow in FIG. 5, gas outside the second arm 4 (inside the transfer chamber 91) flows into the second arm 4 through the second opening 421 or the multiple through holes 831. The above predetermined value (the pressure difference between the internal space of the second arm 4 and the outside when the second valve body 81 opens) is set to a value slightly lower than the pressure resistance of the dustproof seal 46.

[0040] 6, the first valve body 71 (first pressure operated valve 7) is disposed inside the first endless belt 63 in a plan view. The second valve body 81 (second pressure operated valve 8) is disposed inside the second endless belt 66 in a plan view.

[0041] Next, the operation of this embodiment will be described.

[0042] In the workpiece transport system A1 of this embodiment, in the transport chamber 91 (upper transport chamber 91 in FIG. 1) that transports the thin plate-shaped workpiece W to the processing chamber 92, the inside of the transport chamber 91 is set to an atmospheric pressure state, and the transport robot B1 arranged in the transport chamber 91 transports the unprocessed thin plate-shaped workpiece W from the outside. Thereafter, the inside of the transport chamber 91 is depressurized to a vacuum state, and the transport robot B1 transports the thin plate-shaped workpiece W to the processing chamber 92. When the next thin plate-shaped workpiece W is transported, the inside of the transport chamber 91 is switched from the vacuum state to an atmospheric pressure state, and the transport robot B1 transports the unprocessed thin plate-shaped workpiece W from the outside. Also, in the transport chamber 91 (left transport chamber 91 in FIG. 1) that transports the thin plate-shaped workpiece W from the processing chamber 92, the inside of the transport chamber 91 is set to a vacuum state, and the transport robot B1 arranged in the transport chamber 91 transports the processed thin plate-shaped workpiece W from the processing chamber 92. Thereafter, the inside of the transfer chamber 91 is switched from a vacuum state to an atmospheric pressure state, and the transfer robot B1 transfers the thin plate-shaped workpiece W to the outside. When the next thin plate-shaped workpiece W is to be unloaded, the inside of the transfer chamber 91 is depressurized to a vacuum state, and the processed thin plate-shaped workpiece W is unloaded from the processing chamber 92 by the transfer robot B1.

[0043] In this way, in each transfer chamber 91, the inside of the transfer chamber 91 is switched between atmospheric pressure and vacuum every time a thin workpiece W is processed, and the transfer robot B1 arranged in the transfer chamber 91 is frequently switched between atmospheric pressure and vacuum environments. Here, in order to shorten the processing time (cycle time) of the thin workpiece W, it is required to operate the transfer chamber 91 to suddenly release the vacuum state to atmospheric pressure in a short time.

[0044] In the transfer robot B1 of this embodiment, dust seals 36, 46 are arranged between the hollow first arm 3 and the first shaft 44, and between the hollow second arm 4 and the second shaft 51. The first arm 3 and the second arm 4 are provided with dust filters 312, 412 that allow ventilation between the internal space of the arm and the outside. When the transfer chamber 91 is suddenly released from a vacuum state to an atmospheric pressure state in a short time, if the amount of ventilation of the dust filters 312, 412 is small, the internal spaces of the first arm 3 and the second arm 4 are each lower than atmospheric pressure, while the outside of each arm 3, 4 (inside the transfer chamber 91) becomes nearly atmospheric pressure, and the internal spaces of each arm 3, 4 may become relatively low pressure.

[0045] In this embodiment, the first arm 3 and the second arm 4 are provided with a first pressure operated valve 7 and a second pressure operated valve 8. The first pressure operated valve 7 and the second pressure operated valve 8 open so that the internal space of the arm 3, 4 communicates with the outside when the internal space of each arm 3, 4 is at a lower pressure than the outside and the pressure difference between the internal space and the outside is equal to or greater than a predetermined value. Here, if the above-mentioned predetermined value (the pressure difference between the internal space of each arm 3, 4 and the outside when the first pressure operated valve 7 and the second pressure operated valve 8 open) is set to a value slightly lower than the pressure resistance of the dust seals 36, 46, the first pressure operated valve 7 and the second pressure operated valve 8 open when the pressure difference between the internal space of the arm 3, 4 and the outside reaches the set predetermined value, and the outside air flows into the inside of the arm 3, 4. This prevents the pressure difference between the internal space of the arm 3, 4 and the outside from increasing beyond the above-mentioned predetermined value, and the pressure difference between the internal space of the arm 3, 4 and the outside does not exceed the pressure resistance of the dust seals 36, 46. Therefore, in this embodiment, even if the transfer chamber 91 is released from a vacuum state to atmospheric pressure in a short time, the dustproof properties of the dustproof seals 36, 46 are not impaired, and it is possible to shorten the processing time for the thin plate-shaped workpiece W. The pressure difference between the internal space of each arm 3, 4 and the outside when the first pressure operated valve 7 and the second pressure operated valve 8 are opened can be set appropriately depending on the pressure resistance of the dustproof seals 36, 46.

[0046] The first arm 3 and the second arm 4 are formed with a first opening 321 and a second opening 421. The first opening 321 and the second opening 421 are formed at positions corresponding to the first pressure operated valve 7 and the second pressure operated valve 8. The first pressure operated valve 7 and the second pressure operated valve 8 have a first valve body 71 and a second valve body 81. The first valve body 71 and the second valve body 81 close the first opening 321 and the second opening 421 in a closed state, and are displaced inward of the first arm 3 and the second arm 4 in an open state. With this configuration, the first pressure operated valve 7 and the second pressure operated valve 8 can be made to have a relatively simple structure. Furthermore, when the first valve body 71 and the second valve body 81 are opened, they are displaced toward the inside of the first arm 3 and the second arm 4, and gas outside the first arm 3 and the second arm 4 (inside the transfer chamber 91) flows into the first arm 3 and the second arm 4 through the first opening 321 and the second opening 421. This makes it possible to prevent particles inside the first arm 3 and the second arm 4 from leaking out to the outside.

[0047] The first arm 3 and the second arm 4 include upper walls 31, 41 and lower walls 32, 42 that face each other in the vertical direction, and side walls 33, 34 that are connected to both the upper walls 31, 41 and the lower walls 32, 42. The first opening 321 and the second opening 421 are formed in the lower walls 32, 42. With this configuration, the first opening 321 and the second opening 421 can be kept away from the thin workpiece W supported by the hand 5. Therefore, even if a small amount of particles inside the first arm 3 and the second arm 4 leaks out, the particles are prevented from adhering to the thin workpiece W.

[0048] The drive mechanism 6 includes a first endless belt 63 disposed inside the first arm 3 and rotating the first shaft portion 44, and a second endless belt 66 disposed inside the second arm 4 and rotating the second shaft portion 51. The first valve body 71 and the second valve body 81 are disposed inside the first endless belt 63 and the second endless belt 66 in a plan view. With this configuration, even if the first valve body 71 and the second valve body 81 are displaced to the inside of the first arm 3 and the second arm 4 when opening, the first valve body 71 and the second valve body 81 are prevented from contacting the first endless belt 63 and the second endless belt 66. Therefore, the first pressure operated valve (first valve body 71) 7 and the second pressure operated valve 8 (second valve body 81) can be efficiently disposed in the first arm 3 and the second arm 4.

[0049] The first pressure operated valve 7 and the second pressure operated valve 8 have biasing members 74, 84 that apply a biasing force in a direction in which the first valve body 71 and the second valve body 81 close. With this configuration, the pressure difference between the internal space of each arm 3, 4 and the outside when the first valve body 71 and the second valve body 81 open (i.e., the pressing force acting on the first valve body 71 and the second valve body 81 from the outside when the first valve body 71 and the second valve body 81 open) can be easily adjusted by selecting the biasing force of the biasing members 74, 84.

[0050] Although an embodiment of the present invention has been described above, the scope of the present invention is not limited to the above-described embodiment, and all modifications within the scope of the matters described in each claim are all included in the scope of the present invention.

[0051] In the above embodiment, the first valve body 71 of the first pressure operated valve 7 is a swing valve, and the second valve body 81 of the second pressure operated valve 8 is a movable valve that can move up and down. However, instead of this, both the first valve body 71 and the second valve body 81 may be swing valves. Also, both the first valve body 71 and the second valve body 81 may be movable valves that can move up and down. Furthermore, the first pressure operated valve 7 and the second pressure operated valve 8 may adopt a valve structure different from the swing valve or movable valve described above.

[0052] In the above embodiment, in the workpiece transport system A1 shown in FIG. 1, the transport chamber 91 has the functions of both the load lock chamber (or unload lock chamber) and the transfer chamber, but a different configuration may be adopted. FIG. 7 shows another example of a workpiece transport system equipped with a transport robot according to the present invention. The workpiece transport system A2 shown in FIG. 7 includes a transport chamber 91, two processing chambers 92, and two preliminary chambers 93 and 94. The transport chamber 91 is a transfer chamber, and the transport robot B1 is disposed in the transport chamber 91. The preliminary chamber 93 is a load lock chamber, and a thin plate-shaped workpiece W before processing is carried in from the outside through the preliminary chamber 93. The preliminary chamber 94 is an unload lock chamber, and a processed thin plate-shaped workpiece W is carried out to the outside through the preliminary chamber 94. The preliminary chambers 93 and 94 are switched between an atmospheric pressure state and a vacuum state every time a thin plate-shaped workpiece W is processed. The transfer chamber 91 is maintained in a vacuum state when transferring the thin plate-like workpiece W, and can be switched from the vacuum state to an atmospheric pressure state, for example, during maintenance. For the transfer robot B1 disposed in the transfer chamber 91 of the work transfer system A2, by providing the above-mentioned first pressure operated valve 7 and second pressure operated valve 8 on the first arm 3 and second arm 4, the transfer chamber 91 can be released from the vacuum state to the atmospheric pressure state in one go in a short time. This contributes to shortening the time required for maintenance, etc. [Explanation of symbols]

[0053] A1, A2: workpiece transport system, B1: transport robot, 1: fixed base, 2: lift base (mounting base), 3: first arm, 31: upper wall, 312: dust filter, 32: lower wall, 321: first opening, 33: side wall, 36: dust seal, 4: second arm, 41: upper wall, 412: dust filter, 42: lower wall, 421: second opening, 43: side wall, 44: first shaft, 46: dust seal, 5: Hand, 51: second shaft portion, 6: drive mechanism 6, 63: first endless belt, 66: second endless belt, 7: first pressure actuated valve, 71: first valve body, 8: second pressure actuated valve, 81: second valve body, 91: transfer chamber, 92: processing chamber, 901: ventilation valve (switching means), 902: vacuum valve (switching means), 903: vacuum pump (switching means), O1: first vertical axis, O2: second vertical axis, O3: third vertical axis, W: thin plate-like workpiece

Claims

1. A mounting base; a hollow first arm having one end supported on the mounting base so as to be rotatable about a first vertical axis; a hollow second arm having a first shaft portion disposed at one end, the first shaft portion being supported rotatably about a second vertical axis relative to the other end of the first arm; a hand having a second shaft portion, the second shaft portion being supported rotatably about a third vertical axis with respect to the other end of the second arm; a drive mechanism that rotates the first shaft portion and the second shaft portion; a dustproof seal disposed between the first arm and the first shaft portion and between the second arm and the second shaft portion; a dust filter provided in each of the first arm and the second arm, the dust filter allowing ventilation between an internal space of the arm and the outside; a first pressure operated valve and a second pressure operated valve provided on the first arm and the second arm, the first pressure operated valve and the second pressure operated valve opening so as to communicate between the internal space and the outside when the internal space is at a lower pressure than the outside and a pressure difference between the internal space and the outside is equal to or greater than a predetermined value, and closing otherwise; a first opening and a second opening are formed in the first arm and the second arm, the first opening and the second opening corresponding to the first pressure operated valve and the second pressure operated valve, respectively; the first pressure operated valve and the second pressure operated valve have a first valve body and a second valve body that close the first opening and the second opening in a closed state and are displaced inwardly of the first arm and the second arm in an open state, the drive mechanism includes a first endless belt that is disposed inside the first arm and rotates the first shaft portion, and a second endless belt that is disposed inside the second arm and rotates the second shaft portion, The transport robot, wherein the first valve body and the second valve body are disposed inside the first endless belt and the second endless belt in a plan view.

2. each of the first arm and the second arm includes an upper wall and a lower wall opposed to each other in the vertical direction, and a side wall connected to both the upper wall and the lower wall; The transfer robot according to claim 1 , wherein the first opening and the second opening are formed in the lower wall.

3. 3. A work transport system comprising: a transport robot as described in claim 1 or 2; a transport chamber in which the transport robot is disposed; a processing chamber provided adjacent to the transport chamber for performing a predetermined processing on a work; and a switching means for switching the transport chamber between an atmospheric pressure state and a vacuum state.

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