A slot valve assembly (10) including a housing (11) having a central opening (19), a valve plate (32), a strongback (20) for carrying the valve plate, a pair of actuators (34, 36) for raising and lowering the strongback to position the valve plate over opening (19), and a second set of actuators (240) for moving valve plate (32) into seating engagement with housing (11). second actuators (240) are in fluid communication with the working chambers (48, 50) of the first pair of actuators (34, 36). first actuators (34, 36) are located within housing (11) to give the housing a much shorter height.
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0. 19. A valve for creating an air tight seal to a vacuum chamber, comprising
a valve housing defining a valve chamber, the valve housing having first and second aligned openings for passage of air along a flow path from one side of the valve housing to the other side, a valve holder reciprocable within the valve housing between a first holder position remote from said openings and a second holder position between said openings, a valve gate including a seal transversely reciprocable within said holder between a first gate position spaced from said openings and a second gate position sealing off one opening, a first actuator for moving the valve holder between first and second holder positions, and a second fluid actuator carried on the valve holder for moving the valve gate between first and second gate positions, and the valve having a low profile.
1. A slot valve for creating an air tight seal to a vacuum chamber, comprising
a valve housing defining a valve chamber, the valve housing having first and second aligned openings for passage of air along a flow path from one side of the valve housing to the other side, a valve holder longitudinally reciprocable within the valve housing between a first holder position remote from said openings and a second holder position between said openings, a valve gate including a seal transversely reciprocable within said holder between a first gate position spaced from said openings and a second gate position sealing off one opening, a first actuator within the valve chamber for moving the valve holder between first and second holder positions, and a second fluid actuator carried on the valve holder for moving the valve gate between first and second gate positions, the first and second actuators being within the valve chamber, and the slot valve having a low profile.
16. A pneumatic slot valve for sealing off a vacuum chamber, the slot valve comprising
a valve housing defining a valve chamber, the valve housing having first and second aligned openings defining a flow path for the passage of air from one side of the valve housing to the other side. a valve gate movable into and out of seating engagement with the valve housing about the first opening, to seal off the flow path, a first pneumatic actuator within the valve chamber for moving the valve gate into and out of the flow path, the first pneumatic actuator comprising a linear pneumatic motor having a first working chamber for moving the valve gate into the flow path and a second working chamber for moving the valve gate out of the flow path, a second pneumatic actuator for moving the valve gate into seating engagement with the valve housing about the first opening, a valve holder for carrying the valve gate and the first pneumatic actuator, the second peneumatic actuator being in fluid communication with each other, the second pneumatic actuator including biasing means for unseating the valve gate, a high pressure source in fluid communication with the first working chamber for seating the valve gate, a low pressure source in fluid communication with the first and second working chambers of the first pneumatic actuator, for moving the valve holder into and out of the flow path, wherein the pressure necessary to overcome the biasing force of the biasing means is between the high and low pressures provided by the high and low pressure sources.
10. A control system for moving a valve gate longitudinally between first and second holder positions into and out of a flow path and transversely between first and second gate positions into and out of seating engagement with a valve seat, for sealing off the flow path, the control system comprising
a first pneumatic actuator for moving the valve gate between the first and second holder positions into and out of the flow path, the first pneumatic actuator including a first working chamber for moving the valve gate from the first to the second holder position into the flow path and a second working chamber for moving the valve gate from the second to the first holder position out of the flow path, a second pneumatic actuator for moving the valve gate into seating engagement with the valve seat, biasing means for biasing the valve gate to unseat from the valve seat, the second pneumatic actuator and the first working chamber of the first pneumatic actuator being in fluid communication with each other, a high pressure source for providing high pressure air to the first working chamber of the first actuator and to the second actuator, and a low pressure source for providing low pressure air to the first and second working chambers of the first actuator, the biasing means applying a force to bias the valve gate to the second gate position, the biasing means being overcome by pressure in the second between the high and low pressures, means to introduce low pressure into the first working chamber to move the valve gate into the second holder position and high pressure into the first working chamber and into the second actuator to overcome the biasing force of the biasing means and seat the valve gate and seal the flow path, and means to introduce low pressure into the second working chamber and vent high pressure from the second actuator and the first working chamber, to first cause the biasing force to overcome the pressure in the second actuator, then causing the valve gate to unseat, and then causing the pressure in the first chamber to drop below the low pressure in the second working chamber, causing the valve gate to move to the first holder position.
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0. 20. The valve of
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1. Field of the Invention
The present invention pertains to gate valves or slot valves of the type used in vacuum contained automated substrate handling systems, such as may commonly be employed in modular robotic wafer fabricating systems.
2. Related Art
In the semiconductor industry, automated silicon wafer substrate handling systems are utilized to move wafers into and out of process modules that perform various operations on the wafers, such as vapor deposition, ionization, etching, etc. These handling systems are commonly referred to as cluster tools, and an example of such a system is the Marathon Series cluster platforms available from Brooks Automation, Lowell, Mass., USA.
The processes performed on the wafers are done within vacuum chambers, and the cluster platforms and associated equipment are housed in "clean" rooms, the environments of which are strictly controlled. Vacuum chambers and clean rooms are utilized in order to prevent the smallest of particles from being introduced into the wafer matrices In addition, the wafer processing equipment of cluster tools is designed for low particulate generation through millions of cycles of operation. To achieve ultrapure fabrication techniques, processing equipment is employed that has a minimum of moving parts, and to further prevent particle contamination, machine componentry is properly isolated and sealed.
With clean rooms, space utilization is of utmost importance, as the costs for operating a clean room are extremely expensive. Accordingly, there is an advantage in providing more efficient equipment in less space, in order to lower manufacturing costs.
Gate valves (or slot valves) are commonly employed to provide vacuum seals at numerous locations between modular integrated processing equipment. For example, gate valves are positioned between wafer cassette modules and central handling modules, and between central handling modules and process modules. Gate valves open to allow transfer of wafers between modules, and close to seal off modules so that vacuum controlled processes may be performed within the modules.
Present gate valve assemblies include generally a gate valve housing and an actuator housing with associated controls. While these gate valve designs provide narrow profiles, allowing closely adjacent positioning of cooperating modules, the height of such gate valve assemblies can be extensive, which causes space utilization concerns below the processing equipment where associated controls and pumps are positioned. Accordingly, advantages can be achieved in space utilization by reducing the size of all processing and handling equipment, particularly gate valves. The action from components of the present valve are confined within a housing having a height considerably less than conventional actuating systems. This is accomplished, in part, by confining actuating elements within the housing.
Briefly described, the present invention comprises a slot valve for creating an air tight seal to a vacuum chamber, wherein the slot valve includes a valve housing defining a valve chamber. The valve housing has first and second aligned openings from one side of the valve housing to the other side. A valve holder is provided that is longitudinally reciprocable within the valve housing between a first holder position remote from the openings and a second holder position between the openings. The slot valve also includes a valve gate with a seal that is transversely reciprocable within the holder between a first gate position spaced from the openings and a second gate position sealing off one opening. A first actuator is provided within the valve chamber for moving the valve holder between first and second holder positions. A second actuator is carried on the valve holder for moving the valve gate between first and second gate positions. The first and second actuators are positioned within the valve housing, which creates a low profile housing for the slot valve.
According to an aspect of the invention, the second actuator is pneumatically powered to seat the valve gate into engagement about the first opening and is mechanically biased to unseat the valve gate out of engagement about the first opening.
According to another aspect of the invention, the second actuator comprises an expandable bellows chamber mounted at one end to the valve holder and mounted at its other end to the valve gate. The first actuator is pneumatically powered to move the valve holder between first and second holder positions. Pneumatic controls are provided for controlling operation of the first and second actuators. The pneumatic controls are adapted to deliver high pressure to the second actuator to seat the valve gate, with the high pressure being sufficient to overcome the mechanical biasing force attempting to unseat the valve gate.
Preferably, the pneumatic controls are adapted to apply a low pressure to the first actuator to move the valve holder between first and second holder positions. The first pneumatic actuator includes a first working chamber for receiving low pressure air to move the valve holder to the second holder position. The first working chamber of the first actuator and the second actuator are in fluid communication with each other. By controlling the first and second actuators via a common fluid source, the number of moving components necessary to seat the valve gate is substantially reduced.
The pneumatic controls are adapted to introduce high pressure air through the first working chamber of the first actuator and into the second actuator, to seat the valve gate and seal the opening. The first actuator includes a second working chamber for receiving low pressure air to move the valve holder from the second to the first holder position. Wherein upon introduction of low pressure air into the second working chamber of the first actuator, the first actuator does not move the valve holder back to the first holder position until high pressure in the first working chamber drops below the low pressure in the second working chamber, allowing time for the mechanical biasing force to unseat the valve gate.
Preferably, the mechanical biasing force unseats the valve gate at a pressure between the high and low pressures.
The present invention also includes a control system for moving a valve gate longitudinally between first and second holder positions into and out of a flow path and transversely between first and second gate positions into and out of seating engagement with a valve seat, for sealing off the flow path. The control system includes a first pneumatic actuator for moving the valve gate between the first and second holder positions into and out of the flow path. The first pneumatic actuator includes a first working chamber for moving the valve gate from the first to the second holder position into the flow path and a second working chamber for moving the valve gate from the second to the first holder position out of the flow path. The control system also includes a second pneumatic actuator for moving the valve gate into seating engagement with the valve seat. Biasing means is provided for biasing the valve gate to unseat from the valve seat. The second pneumatic actuator and the first working chamber of the first pneumatic actuator are in fluid communication with each other. The control system also includes a high pressure source for providing high pressure air to the first working chamber of the first actuator and to the second actuator, and a low pressure source for providing low pressure air to the first and second working chambers of the first actuator. The pressure necessary to overcome the biasing force of the biasing means to seat the valve gate is between the high and low pressures. In operation, low pressure introduced into the first working chamber moves the valve gate into the second position and high pressure introduced into the first working chamber and into the second actuator overcomes the biasing force of the biasing means and seats the valve gate and seals the flow path. Introduction of low pressure into the second working chamber and venting of high pressure from the second actuator and to the first working chamber first causes the biasing force to overcome the pressure in the second actuator and thereby causing the valve gate to unseat, and then causes the pressure in the first chamber to drop below the low pressure in the second working chamber, causing the valve gate to move out of the flow path.
These and other features, objects, and advantages of the present invention will become apparent from the following description of the best mode, when read in conjunction with the accompanying drawings, and the claims, which are all incorporated herein as part of the disclosure of the invention.
The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments of the invention and, together with the description serve to explain the principles of the invention.
Reference will now be made in detail to the preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in conjunction with the preferred embodiments, it will be understood that the preferred embodiments are not intended to limit the invention to those embodiments disclosed herein. On the contrary, the invention is intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope of the invention as defined by the appended claims.
Referring to
Front housing plate 12 includes an elongated rectangular opening 18, which is aligned with a similar elongated rectangular opening (not shown) in back housing plate 14. The aligned openings in the front and back housing plates form a central opening 19 in housing 11, through which robotic wafer or flat panel handling equipment can move to transfer wafers or the like between a transfer module and various process modules. The aligned openings forming central opening 19 also define a flow path through housing 11 through which gases move as adjacent module chambers are evacuated. An upright, elongated, and relatively flat rectangular strongback plate 20 is longitudinally movable up and down within the interior valve chamber of housing 11 between a first holder position remote from the aligned openings (i.e. out of the flow path) and a second holder position between the openings. Strongback 20 carries or supports a valve plate (not shown), and in this sense acts as a valve holder. Strongback 20 is raised and lowered by internal actuators to the position shown in FIG. 1. Pneumatic fittings and ports, indicated generally by reference numeral 22, communicate with the pair of internal pneumatic actuators used to raise and lower strongback 20. When the strongback 20 is moved to the position shown in
Housing pieces 12, 14 and 16 include a series of recesses 24 that include inwardly directed flanged rims, which cooperate with various types of clamp mechanisms to secure slot valve assembly 10 in position between system modules.
In
In
In
Valve plate 32 and strongback 20 extend between a pair of first pneumatic actuators 34, 36. As discussed in more detail later, strongback 20 is mounted between the vertically movable piston rod components of actuators 34, 36, and valve plate 32 is horizontally slidably carried on strongback 20 and is movable into sealing engagement with the housing by a set of second pneumatic actuators also carried on strongback 20.
As shown in
Each actuator 34, 36 has associated with it a set of pneumatic fittings and ports 22, which provide for fluid communication between working chambers 48, 50 and pneumatic hoses (not shown). Cap pieces 52, 54 are mounted over end sections 56, 58 of bonnet plate 16. Each cap piece 52, 54 closes off a first working chamber 48 of each first actuator 34, 36. Cap pieces 5254 also include ports that receive fittings for coupling pneumatic lines to the actuators.
A air of expandable steel bellows 90, 92 are provided for enclosing and sealing piston rod 42. One end of bellows 90 is mounted in a sealed manner to a bellows end flange 94 that is mounted to the closed end 84 of cylinder component 38. One end of bellows 92 is mounted in a sealed manner to an annular lock ring 96 that is secured within an annular groove in piston rod 42. Lock ring 96 engages strongback 20 and when piston rod 42 is extended causes the strongback to move into position over the central opening of the slot valve assembly. A tubular bellows guide sleeve 98 has an outwardly extending flange 100 and is slidably movable on piston rod 42. Bellows 90, 92 are mounted at their inner ends to opposite sides of flange 100. Flange 100 includes a set of four openings 102 (only two shown) for providing fluid communication between the chambers 103, 105 formed by bellows 90 and 92.
Cylinder component 38 includes a first longitudinal side wall bore 104, which extends the length of the cylinder. Bore 104 communicates at one end with port 62 and fitting 62', and at its other end with bellows chambers 103, 105. Cylinder end wall 84 and bellows flange 94 include ports (not shown) that define a channel providing fluid communication between chambers 103, 105 and bore 104. Bore 104 allows bellows chambers 103, 105 to breathe as the piston rod is extended and retracted.
Cylinder component 38 includes a second longitudinal bore 110, which extends substantially the length of the cylinder, and is located opposite to bore 104. Bore 110 terminates at cylinder end wall 84. For actuator 36, bore 110 is nonfunctional. However, actuator 34 includes a similar bore which provides access for positioning a reed switch or other type of sensor (not shown) adjacent the closed end 84 of cylinder component 38. The reed switch within bore 110 functions to signal when piston 40 bottoms out against cylinder end wall 84.
Referring back to
Cylinder component 38 includes a fourth longitudinal bore 114 that communicates at one end with port 66 and fitting 66' and at its other end communicates with second working chamber 50 via a transverse channel 116.
Referring back to
Top piece 140 includes a longitudinal slot or groove 152 that has angled outer ends sections 153. Outer end sections 153 terminate at flange openings 148', 150'. Grooves 152, 153 form a longitudinal fluid passageway within strongback 20 and thus provides fluid communication between openings 148', 150'. The longitudinal bore and annular groove of each piston rod are in fluid communication with longitudinal groove 152. Thus, the first working chambers of the first pneumatic actuators are in fluid communication with each other via longitudinal groove 152, 153, which serves to balance the pressures within the working chambers of each actuator and thus equalize the actuator forces at each end of strongback 20.
Top piece 140 includes end flanges 154, 156 and a main body section 158. End flanges 154, 156, together with the outer end portions of bottom piece 142, form the flanges 46 of strongback 20. Main body section 158 is narrower than end flanges 154, 156 (FIG. 10). The narrow body of strongback 20 provides space, as shown by arrows 160, for positioning the valve plate within the footprint of strongback 20.
The main body 158 of strongback 20 further includes a set of three vertical passageways 162 that communicate with longitudinal passageway 152, and a set of three upper short passageway segments 164, which communicate with vertical passageways 162 and with the second set of pneumatic actuators carried on strongback 20.
In
Back side 180 of top piece 140 includes three laterally spaced large circular pockets 182. Within each pocket 182 is formed a set of four small openings 184. Each opening 184 is equally spaced from transverse conduit 164. Pockets 182 each receive one end of a second pneumatic actuator, which is secured to strongback 20 by means of fasteners that extend through openings 184.
Top piece 140 also includes a set of four contact head bores 186, which for the aluminum version of the slot valve assembly, receive 440 stainless steel contact heads (not shown). The contact heads engage the inner sidewall of the front housing plate when the valve plate is seated against the back housing plate.
In
Referring to
In a first of their two positions, solenoid valves 290, 292 connect lines 284, 288 with manifold block 294, and in the second of their two positions, solenoid valves 290, 292 block lines 284, 288, and vent the lines leading from manifold block 294.
A second splitter 296 connects with pneumatic lines 298, 300, which lead to fittings 66' and provide fluid communication with the second working chambers of the first pneumatic actuators. Pneumatic lines 302, 304 lead from a third splitter 297 to fittings 64' and provide fluid communication with the first working chambers of the first pneumatic actuators. Lines 306, 308 connect with fittings 62' and vent the bellows chambers enclosing the piston rods of the first pneumatic actuators.
After a predetermined time, slow start control valve 295 will cease metering pressure, allowing 80 psi pressure to move all the way into working chambers 247 of the second actuators. 80 psi pressure is sufficient to overcome the biasing forces of the spring coils, and valve plate 32 moves to its second gate position into seating engagement with the inner wall of the housing, as shown in FIG. 23B. The slow start control valve provides time for the piston rods to extend and position the strongback and valve plate into position about the openings in the housing.
Referring to
Meanwhile, the spring coils are selected to overcome a pressure that is greater than the pressure at which the pistons of the first actuators will start to move to retract the piston rods. Such a pressure may be for example 65 psi. When the bellows chambers 247 drop below this pressure, the spring coils retract valve plate 32, unseating it from the housing, as shown in FIG. 24B.
When the pressure in the first working chambers drops to approximately 50 psi, the pressure differential acting on the pistons is sufficient to retract the pistons and their piston rods into the cylinders, as shown in
From the foregoing description, it can be seen that a compact slot valve assembly is provided that includes a minimum of moving parts and which is pneumatically controlled in a manner that substantially reduces the potential for particulate buildup.
The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.
Patent | Priority | Assignee | Title |
10541157, | May 18 2007 | BROOKS AUTOMATION HOLDING, LLC; Brooks Automation US, LLC | Load lock fast pump vent |
10854478, | May 18 2007 | BROOKS AUTOMATION HOLDING, LLC; Brooks Automation US, LLC | Load lock fast pump vent |
11803129, | Aug 13 2021 | Taiwan Semiconductor Manufacturing Company, Ltd | Semiconductor processing tool and methods of operation |
7422653, | Jul 13 2004 | Applied Materials, Inc. | Single-sided inflatable vertical slit valve |
7445019, | May 15 2006 | HIGH VACUUM APPARATUS MFG , INC | Gate valve having service position |
8083207, | Nov 13 2007 | Lam Research Corporation | Apparatus for gate valve movement in a minimum-space wet process environment |
8662812, | May 18 2007 | BROOKS AUTOMATION HOLDING, LLC; Brooks Automation US, LLC | Load lock fast pump vent |
9478446, | May 18 2007 | BROOKS AUTOMATION HOLDING, LLC; Brooks Automation US, LLC | Load lock chamber |
Patent | Priority | Assignee | Title |
1524267, | |||
4131131, | Jun 22 1977 | Dayco Corporation | Valve construction |
4164211, | Oct 03 1977 | BANK OF NOVA SCOTIA, THE | Damper assembly |
4412671, | Nov 26 1980 | Sulzer Brothers Limited | Plate valve |
4560141, | Jun 30 1982 | Siegfried, Schertler | Vacuum gate valve |
5163478, | Aug 31 1990 | Festo AG & Co | Spool valve having improved sealing characteristics |
5169125, | Mar 05 1991 | Baker Hughes Incorporated | Self-aligning gate valve |
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