TWI735589B - A stage assembly for positioning a workpiece, an exposure apparatus and a process for manufacturing a device - Google Patents

Abstract

A stage assembly for positioning a workpiece includes a stage, a base, a fluid actuator assembly, and a control system. The stage retains the workpiece. The fluid actuator assembly moves the stage along the movement axis relative to the base. The fluid actuator assembly includes a piston housing that defines a piston chamber, a piston that is positioned within and moves relative to the piston chamber along a piston axis, and a valve assembly that controls the flow of a piston fluid into the piston chamber. The valve assembly includes a first inlet valve having a first inlet valve characteristic. The control system controls the valve assembly to control the flow of the piston fluid into the piston chamber. The control system can utilize an inverse of the first inlet valve characteristic to control the valve assembly.

Description

Platform assembly for positioning workpieces, exposure equipment, and program for manufacturing a device

Exposure equipment is usually used to transfer images from a mask to a workpiece such as an LCD flat panel display or a semiconductor wafer. Typical exposure equipment includes: an illumination source; a mask platform assembly, which holds and accurately positions the mask; a lens assembly; a workpiece platform assembly, which holds and accurately positions the workpiece; and a measurement system, which monitors the mask And the position or movement of the workpiece. There has never been a desire to reduce the cost of the actuators used to position the mask and/or the workpiece, while still accurately positioning these components.

The present invention relates to a platform assembly for positioning a workpiece along a moving axis. In one embodiment, the platform assembly includes a platform, a base, a fluid actuator assembly, and a control system. The platform is adapted to hold the workpiece. The fluid actuator assembly is coupled to the platform and moves the platform relative to the base along the movement axis. The fluid actuator assembly may include: a piston housing defining a piston chamber; a piston positioned in the piston chamber and moving relative to the piston chamber along a piston axis; and a valve The assembly controls the flow of a piston fluid into the piston chamber. The valve assembly includes one of the characteristics of a first inlet valve The first inlet valve. The control system controls the valve assembly to control the flow of the piston fluid into the piston chamber. In some embodiments, the control system uses one of the first inlet valve characteristics to reverse to control the valve assembly.

In one embodiment, the piston fluid is a gas, and the invention is described as a pneumatic control application. Alternatively, the piston fluid may be a liquid such as oil, and different equations may be used.

As provided herein, the control system precisely controls the fluid pressure on each side of the piston to generate the required force to accurately drive and position the platform. In some embodiments, the valve assembly is evaluated to identify non-linearities embedded in the system. These non-linearities include the valve characteristics of each valve. Non-exclusive examples of valve characteristics include: (i) fluid pressure changes with chamber volume; (ii) proportional valve backlash and differential pressure dependence; and (iii) fluid flow associated with upstream and downstream pressures Non-linear. These nonlinearities can be identified through testing, modeling, or simulation. Subsequently, the valve characteristics are reversed and used in a control loop of the control system to linearize the system and accurately control the fluid actuator assembly.

Therefore, the system non-linearity problem of hydraulic cylinder pressure and valve dynamics associated with applying a hydraulic cylinder to the platform trajectory movement has been solved by incorporating the identified system dynamics model into the control design.

In some embodiments, the piston separates the piston chamber into a first chamber and a second chamber on opposite sides of the piston. In addition, the valve assembly controls the flow of the piston fluid into and out of the first chamber and the second chamber.

In one embodiment, the valve assembly includes: (i) the first inlet valve, which controls the flow of the piston fluid into the first chamber; (ii) a first outlet valve, which controls the valve The flow of plug fluid leaving the first chamber; (iii) a second inlet valve that controls the flow of the piston fluid into the second chamber; and (iv) a second outlet valve that controls the piston The flow of fluid leaving the second chamber. In addition, the first outlet valve has a first outlet valve characteristic; the second inlet valve has a second inlet valve characteristic; and the second outlet valve has a second outlet valve characteristic. In this embodiment, the control system also uses an inversion of the first outlet valve characteristic, an inversion of the second inlet valve characteristic, and an inversion of the second outlet valve characteristic to control the valve assembly.

As a non-exclusive example, the experimental test of the first inlet valve can be used to determine the characteristics of the first inlet valve, the experimental test of the first outlet valve can be used to determine the characteristics of the first outlet valve, and the second The experimental test of the inlet valve is used to determine the characteristics of the second inlet valve, and the experimental test of the second outlet valve can be used to determine the characteristics of the second outlet valve.

As provided herein, for example, each valve characteristic can be: (i) the relationship between the current command for the valve and an effective orifice area; (ii) the current command for the valve and the valve The relationship between the positions; and/or (iii) the relationship between the effective orifice area of the valve and the valve position.

The present invention also relates to an exposure equipment and a process for manufacturing a device. The process includes the following steps: providing a substrate; and using the exposure equipment to form an image on the substrate.

The invention also relates to a method for positioning a workpiece along a moving axis. In one embodiment, the method includes: (i) providing a base; (ii) coupling the workpiece to a platform; (iii) using a fluid actuator assembly to move the platform along the movement axis, The fluid actuator assembly includes: a piston housing defining a piston chamber; a piston positioned in the piston chamber and moving relative to the piston chamber along a piston axis; and a valve assembly become, It controls the flow of a piston fluid into the piston chamber; wherein the valve assembly includes a first inlet valve having a first inlet valve characteristic; and (iv) using a control system to control the valve assembly to control the valve assembly The flow of piston fluid into the piston chamber, wherein the control system uses one of the first inlet valve characteristics to reverse to control the valve assembly.

10: Platform assembly

12: Base

14: Platform

16: Platform mover assembly

18: Measurement system

20: Control system

20A: processor

20B: Electronic data storage

22: Workpiece

24: Fluid actuator assembly

26: Pedestal mounting table

28: Bearing assembly

30: moving axis

31: Piston assembly

32: Piston housing

32A: Tubular side wall

32B: Disc-shaped first end wall

32C: Disc-shaped second end wall

32D: Wall pores

34: Piston chamber

34A: first chamber

34B: second chamber

36: Piston

36A: Piston axis

36B: Piston body

36C: Piston seal

36D: The first beam

36E: second beam

38: valve assembly

38A: First valve sub-assembly

38B: Second valve sub-assembly

38C: First inlet valve

38D: First outlet valve

38E: second inlet valve

38F: second outlet valve

40: Piston fluid

42: Piston mounting table

44: Total force (F)

46: fluid pressure source

46A: fluid storage tank

46B: Compressor

46C: Pressure regulator

260: Platform reference block

262: Platform Feedback Controller

264: Platform feedforward controller

266: Feedback Converter

268: Feedforward converter

270: The first chamber controller

272: The second chamber controller

278: Chamber Volume Estimator

290: Pressure feedback controller

292: Pressure to mass flow converter

294: Inlet mass flow to orifice area converter

296: Outlet mass flow to orifice area converter

297: Entrance orifice area to current converter

298: Outlet orifice area to current converter

334i: Chamber

338i: Valve sub-assembly

338ii: inlet valve

338io: outlet valve

340: Pressurized Piston Fluid

346: Pressure Source

400: pipeline

402: Orifice

538: Valve

539A: Valve housing

539B: movable valve body

539C: Inlet duct

539D: Outlet duct

539E: Elastic member

539F: Solenoid

600A: line

600B: line

602A: Line

602B: Line

604A: Line

604B: Line

606A: Line

606B: Line

608A: Line

608B: Line

610A: Line

610B: Line

612A: Line

612B: Line

614: Valve characteristics

616: Reversal valve characteristics

738: Valve

739A: Valve housing

739B: movable valve body

739D: Exit opening

739E: Elastic member

739F: Solenoid

814: Valve Characteristics

816: Reverse valve characteristics

914: Valve characteristics

1014: First valve characteristics

1015: Second valve characteristics

1016: Reverse valve characteristics/graphics

1017: Reverse valve characteristics/graphics

1110: Board platform assembly

1120: control system

1122: Workpiece

1170: Exposure equipment

1172: device frame

1182: lighting system

1184: Masking platform assembly

1186: optical assembly

1188: Mask

1192: Illumination source

1194: Illumination optics assembly

1201: Step

1202: Step

1203: Step

1204: Step

1205: Step

1206: step

The novel features of the present invention and the present invention itself (both with regard to its structure and operation) will be best understood from the accompanying drawings in conjunction with the accompanying description. Similar reference numerals in the drawings refer to similar parts, and in the drawings Middle: Figure 1 is a simplified side view description of the platform assembly with the features of the present invention; Figure 2A is a control block diagram illustrating the method for controlling the fluid actuator assembly; Figure 2B is the control block of the chamber controller Figure; Figure 3 is a simplified illustration of a piston chamber and a valve subassembly with the features of the present invention; Figure 4 is a simplified illustration of a pipeline including an orifice; Figures 5A to 5C are a non-exclusive valve A simplified cross-sectional view of an example; Fig. 6A is a graph illustrating the valve characteristics of the valve of Figs. 5A to 5C; Fig. 6B is a graph illustrating the reversal valve characteristics of the valve of Figs. 5A to 5C; Figs. 7A to 7D are in A simplified illustration of another type of valve at various valve positions; Fig. 7E is a simplified illustration of the outlet and valve body in a partially open position; Fig. 8A is a simplified illustration of the valve used in the description of Figs. 7A to 7D Figure 8B is a graph plotting the position of the sliding shaft versus the area of the normalized effective orifice; Figure 9A is a graph illustrating the test results of the spool valve; Fig. 9B is a graph illustrating the simulation results of the spool valve; Fig. 10A illustrates the two valve characteristics of the spool valve; Fig. 10B illustrates the characteristics of two reversing valves; Fig. 11 is a schematic illustration of an exposure apparatus having the characteristics of the present invention And FIG. 12 is a flowchart outlining a procedure for manufacturing a device according to the present invention.

Fig. 1 is a simplified illustration of the platform assembly 10. The platform assembly 10 includes a base 12, a platform 14, a platform mover assembly 16, a measurement system 18, and a control system 20 (illustrated as a box). The design of each of these components can be changed to suit the design requirements of the platform assembly 10. The platform assembly 10 is particularly useful for accurately positioning the workpiece 22 (sometimes referred to as a device) during manufacturing and/or inspection procedures.

As an overview, in certain embodiments, the platform mover assembly 16 includes a fluid actuator assembly 24 that is relatively inexpensive to manufacture. In addition, after the unique calibration and identification procedures provided herein, the control system 20 can control the fluid actuator assembly 24 to accurately position the workpiece 22. As a result, the platform assembly 10 is less expensive to manufacture, and the workpiece 22 is still positioned with the required degree of accuracy.

The type of workpiece 22 positioned and moved by the platform assembly 10 can vary. For example, the workpiece 22 can be an LCD flat panel display, a semiconductor wafer or a mask, and the platform assembly 10 can be used as part of an exposure equipment. Alternatively, for example, the platform assembly 10 can be used to move other types of devices during manufacturing and/or inspection, to move devices under an electron microscope (not shown in the figure), or to perform precision measurement operations (not shown in the figure). ) During the mobile device.

Some of the diagrams provided in this article include specifying the orientation of the X-axis, Y-axis and Z-axis system. It should be understood that the orientation system is for reference only and can be varied. For example, the X axis and the Y axis can be switched, and/or the platform assembly 10 can be rotated. In addition, these iso-axes may alternatively be referred to as a first axis, a second axis, or a third axis.

The base 12 supports the platform 14. In the non-exclusive embodiment illustrated in FIG. 1, the base 12 is rigid and has a substantially rectangular plate shape. In addition, the base 12 can be fixedly fastened to the base mounting table 26. Alternatively, the base 12 may be fastened to another structure.

The platform 14 holds the workpiece 22. In one embodiment, the platform is accurately moved relative to the base 12 by the platform mover assembly 16 to accurately position the platform 14 and the workpiece 22. In FIG. 1, the platform 14 has a substantially rectangular shape and includes a device holder (not shown) for holding a workpiece 22. The device holder may be a vacuum chuck, an electrostatic chuck, or some other type of clamp that directly couples the workpiece 22 to the platform 14. In the embodiment described herein, the platform assembly 10 includes a single platform 14 that holds a workpiece 22. Alternatively, for example, the platform assembly 10 may be designed to include multiple platforms that are independently moved and positioned. As an example, the platform assembly 10 may include a rough platform (not shown in the figure) moved by the platform mover assembly 16, and hold the workpiece 22 and use the fine platform mover assembly (not shown in the figure) relative to the rough platform And the mobile fine platform (not shown in the picture).

In addition, in FIG. 1, a bearing assembly 28 that allows the platform 14 to move relative to the base 12 can be used to support the platform 14 relative to the base 12. For example, the bearing assembly 28 may be a roller bearing, a fluid bearing, a linear bearing, or another type of bearing.

The measurement system 18 monitors the movement and/or position of the platform 14 relative to a reference (such as the optical assembly (not shown in FIG. 1) or the base 12), and provides measurement information to the control system 20. With this information, the control system 20 can be used to control the platform mover assembly 16 for precision Position the platform 14 accurately. The design of the measurement system 18 can be changed according to the movement requirements of the platform 14. In one embodiment, the measurement system 18 may include a linear encoder that monitors the movement of the platform 14 along the Y axis. Alternatively, the measurement system 18 may include an interferometer, or another type of movement or position sensor.

The platform mover assembly 16 is controlled by the control system 20 to move the platform 14 relative to the base 12. In FIG. 1, the platform mover assembly 16 includes a fluid actuator assembly 24 that moves the platform 14 along a single movement axis 30 (eg, Y axis).

The design of the fluid actuator assembly 24 can be varied in accordance with the teachings provided herein. In a non-exclusive embodiment, the fluid actuator assembly 24 includes: (i) a piston assembly 31, which includes a piston housing 32 defining a piston chamber 34, and a piston 36 positioned in the piston chamber 34 And (ii) the valve assembly 38, which controls the flow of piston fluid 40 (illustrated as small circles) into and out of the piston chamber 34. For example, the piston fluid 40 may be air or another type of fluid. The design of these components can be changed in accordance with the teachings provided herein.

In one embodiment, the piston housing 32 is rigid and defines a substantially right cylindrical piston chamber 34. In this embodiment, the piston housing 32 includes: a tubular side wall 32A; a disc-shaped first end wall 32B; and a disc-shaped second end wall 32C, which is separated from the first end wall 32B. One or both of the end walls 32B, 32C may include a wall aperture 32D for receiving a portion of the piston 36.

The piston housing 32 can be fixedly fastened to the piston mounting table 42. Alternatively, the piston housing 32 may be fastened to another structure, such as the base 12. Alternatively, because the piston housing 32 receives the reaction force generated by the platform mover assembly 16, the piston housing 32 can be coupled to counteract, reduce, and minimize the reaction force from the platform mover assembly 16 to other forces. The reaction assembly that affects the position of the structure. For example, the piston housing 32 can be coupled to be maintained at The large counterweight mass (not shown) above the counterweight mass support (not shown in the figure), the counterweight mass support has a reaction bearing that allows the piston housing 32 to move along the moving axis 30 (in the figure) Not shown).

The piston 36 is positioned in the piston chamber 34 and moves relative to the piston chamber 34 along the piston axis 36A. In some embodiments, the piston axis 36A is coaxial with the movement axis 30. In the non-exclusive embodiment illustrated in FIG. 1, the piston 36 includes: (i) a rigid disc-shaped piston body 36B; (ii) a piston seal 36C that seals the area between the piston body 36B and the piston housing 32 (Iii) the rigid first beam 36D, which is attached to the piston body 36B and cantilever away from the piston body 36B, and extends through the wall aperture 32D in the first end wall 32B; (iv) the rigid second beam 36E, which is attached Is connected to the piston body 36B and cantilever away from the piston body 36B, and extends through the wall aperture 32D in the second end wall 32C; (iv) a first beam seal (not shown), which seals the first beam 36D and the first beam 36D The area between one end wall 32B; and (v) a second beam seal (not shown), which seals the area between the second cross beam 36E and the second end wall 32C.

In this embodiment, the second cross beam 36E is also fixedly fastened to the platform 14. In other words, the second beam 36E extends between the piston body 36B and the platform 14 so that the movement of the piston body 36B causes the platform 14 to move. In addition, in this embodiment, the first beam 36D is included so that the effective area on each side of the piston body 36B is the same for the sake of simplicity of calculation. Alternatively, for example, the fluid actuator assembly 24 may be designed without the first beam 36D. In this design, the effective area on the left side of the piston body 36B is larger than the effective area on the right side.

The piston body 36B separates the piston chamber 34 into a first chamber 34A (also referred to as "chamber 1") and a second chamber 34B (also referred to as "chamber 2" on the opposite side of the piston body 36B). "). In FIG. 1, the first chamber 34A is on the left side of the piston body 36B, and the second chamber 34B is on the right side of the piston body 36B. In addition, the first chamber 34A has an effective piston area (A ₁ ) of chamber 1 and is filled with a first pressure (P ₁ ), a first temperature (T ₁ ), and a first volume (V ₁ ). Piston fluid 40. Similarly, the second chamber 34B has an effective piston area (A ₂ ) of chamber 2 and is filled with a second pressure (P ₂ ), a second temperature (T ₂ ), and a second volume (V ₂ ) The piston fluid 40. In the non-exclusive example illustrated in FIG. 1, the fluid actuator assembly 24 is designed such that the effective piston area (A ₁ ) of chamber 1 is approximately equal to the effective piston area (A ₂ ) of chamber 2.

_{The first pressure (P 1} ) of the piston fluid 40 in the first chamber 34A generates a first force (F _{1 ) on the piston body 36B, and the second pressure (P 2} ) of the piston fluid 40 in the second chamber 34B _{) A second force (F 2} ) is generated on the piston body 36B. The total force (F) 44 (illustrated by the arrow) generated by the fluid actuator assembly 24 is equal to the first force (F ₁ ) minus the second force (F ₂ ) (F=F ₁ -F ₂ ).

With the non-exclusive design illustrated in Figure 1, when the first pressure (P ₁ ) is greater than the second pressure (P ₂ ), the first force (F ₁ ) is greater than the second force (F ₂ ), and the total The force (F) is positive and pushes the piston body 36B and the platform 14 from left to right. In contrast, when the first pressure (P ₁ ) is less than the second pressure (P ₂ ), the first force (F ₁ ) is less than the second force (F ₂ ), and the total force (F) is negative and goes from right to left Push the piston body 36B and the platform 14.

In one embodiment, the valve assembly 38 is controlled by the control system 20 to accurately and individually control the pressure in each chamber 34A, 34B. As a non-exclusive embodiment, the valve assembly 38 includes: (i) a first valve sub-assembly 38A, which is controlled to control the flow of the piston fluid 40 into and out of the first chamber 34A and accurately control the first pressure (P ₁ ); and (ii) The second valve sub-assembly 38B, which is controlled to control the flow of the piston fluid 40 into and out of the second chamber 34B to accurately control the second pressure (P ₂ ). In this embodiment, the first valve subassembly 38A includes: a first inlet valve 38C, which is controlled to control the flow of the piston fluid 40 into the first chamber 34A; and a first outlet valve 38D, which is controlled to control The piston fluid 40 leaves the flow of the first chamber 34A. Similarly, the second valve subassembly 38B includes: a second inlet valve 38E, which is controlled to control the flow of the piston fluid 40 into the second chamber 34B; and a second outlet valve 38F, which is controlled to control the piston fluid 40 The flow leaving the second chamber 34B.

In this embodiment, the fluid actuator assembly 24 may include fluid pressure sources 46 (two are shown) that provide pressurized piston fluid 40 to one of the inlet valves 38C, 38E. In addition, each of the fluid pressure sources 46 may include a fluid reservoir 46A, a compressor 46B that generates pressurized piston fluid 40 in the reservoir 46A, and a pressure that controls the pressure of the piston fluid 40 delivered to the inlet valves 38C, 38E Adjuster 46C. In addition, the outlet valves 38D, 38F may open to the atmosphere or open to a low pressure area, such as a vacuum chamber.

In certain embodiments, each of the valves 38C, 38D, 38E, 38F includes one or more valve characteristics that affect the control of these valves 38C, 38D, 38E, 38F. For example, (i) the first inlet valve 38C has one or more first inlet valve characteristics; (ii) the first outlet valve 38D has one or more first outlet valve characteristics; (iii) the second inlet valve 38E Having one or more second inlet valve characteristics; and/or (iv) the second outlet valve 38F has one or more second outlet valve characteristics. In one embodiment, each valve 38C, 38D, 38E, 38F is individually tested to determine the individual valve characteristics of the respective valves 38C, 38D, 38E, and 38F. With this design, the individual valve characteristics of the respective valves 38C, 38D, 38E, and 38F are used to control each valve 38C, 38D, 38E, and 38F. Alternatively, if each valve 38C, 38D, 38E, 38F is similar and has similar valve characteristics, one of the valves 38C, 38D, 38E, 38F can be tested and the valve characteristics of the other valve can be used to control the valves 38C, 38D , 38E, 38F all.

The types of valves 38C, 38D, 38E, and 38F used can vary. As a non-independence For example, each valve 38C, 38D, 38E, 38F may be a proportional valve, such as a poppet ("mushroom") valve or a spool type valve.

The type of valve characteristics will vary according to the type of valve 38C, 38D, 38E, 38F used. The pairing of non-exclusive types of valves 38C, 38D, 38E, and 38F with non-exclusive examples of valve characteristics is described in detail below. It should be noted that the valves 38C, 38D, 38E, 38F may be different from the examples provided herein, and the valve characteristics may be different from the examples provided herein.

As provided herein, for each valve 38C, 38D, 38E, 38F, its corresponding valve characteristic can be determined through experimental testing, simulation, or a combination of the two.

The control system 20 controls the valve assembly 38 to control the flow of the piston fluid 40 into and out of each chamber 34A, 34B. By selectively controlling the flow of the piston fluid 40 into and out of each chamber 34A, 34B, the valve assembly 38 can be controlled to generate a controllable force 44 on the piston body 36B that accurately moves the piston body 36B and the platform 14 ( "F").

The control system 20 is electrically connected to and controls the current directed to the valve assembly 38 to accurately position the platform 14 and the workpiece 22. In one embodiment, the control system 20 uses information from the measurement system 18 to perform the following operations: (i) continuously determine the position ("x") of the platform 14; and (ii) direct current to the valve assembly 38 To position the platform 14. The control system 20 may include one or more processors 20A and an electronic data storage 20B. The control system 20 uses one or more algorithms to perform the steps provided herein.

In some embodiments, the control system 20 individually controls each of the first valves 38C, 38D to control the first pressure (P ₁ ) in the first chamber 34A to generate the desired first force (F ₁ ) . Similarly, the control system 20 individually controls each of the second valves 38E, 38F to control the second pressure (P ₂ ) in the second chamber 34B to generate the desired second force (F ₂ ). Therefore, by controlling the valves 38C, 38D, 38E, and 38F, the control system 20 can control the fluid actuator assembly 24 to generate the desired total force (F) 44 on the platform 14.

In some embodiments, when the control system 20 determines that the piston fluid 40 needs to be added to the first chamber 34A, the control system 20 controls the first outlet valve 38D to be closed, and controls the first inlet valve 38C to be properly opened. The amount to add piston fluid 40. In addition, when the control system 20 determines that the piston fluid 40 needs to be removed from the first chamber 34A, the control system 20 controls the first inlet valve 38C to be closed, and controls the first outlet valve 38C to open an appropriate amount to release the piston fluid 40. In this example, one of the first valves 38C, 38D is controlled to be closed at any given time. Alternatively, the control system 20 may control both the first valves 38C, 38D to be open during the addition and/or removal of the piston fluid 40 from the first chamber 34A.

Similarly, when the control system 20 determines that it is necessary to add the piston fluid 40 to the second chamber 34B, the control system 20 controls the second outlet valve 38F to be closed, and controls the second inlet valve 38E to open an appropriate amount to add the piston Fluid 40. In addition, when the control system 20 determines that it is necessary to remove the piston fluid 40 from the second chamber 34B, the control system 20 controls the second inlet valve 38E to be closed, and controls the second outlet valve 38F to open an appropriate amount to release the piston fluid 40. In this example, one of the second valves 38E, 38F is controlled to be closed at any given time. Alternatively, the control system 20 may control both the second valves 38E, 38F to be open during the addition and/or removal of the piston fluid 40 from the second chamber 34B.

Precise fluid pressure control is performed on the two chambers 34A, 34B to generate the required force 44 to drive the platform 14. In order to accurately control the fluid actuator assembly 24, it is critical to determine the nonlinearity embedded in the system, such as: (i) fluid pressure changes with the chamber volume; (ii) proportional valves 38C, 38D, 38E, 38F is dependent on backlash and differential pressure; and (3) is related to upstream and downstream pressure The fluid flow of the coupling is non-linear. Through experimental testing and/or modeling, these nonlinearities can be identified and compensated for by the control system 20.

For example, the control system 20 may perform the following operations: (i) use the reversal of the first inlet valve characteristic to control the first inlet valve 38C; (ii) use the reversal of the first outlet valve characteristic to control the first outlet valve 38D; (iii) Use the reversal of the second inlet valve characteristic to control the second inlet valve 38E; and (iv) Use the reversal of the second outlet valve characteristic to control the second outlet valve 38F. Because the control system 20 utilizes the reversal of the characteristics of each valve, each valve 38C, 38D, 38E, and 38F can be controlled with improved accuracy.

2A is a control block diagram 220 illustrating a non-exclusive example of a method for controlling the fluid actuator assembly 24 to accurately position the platform 14. More specifically, the control block diagram 220 illustrates a non-exclusive method for directing current to the valve assembly 38 to control the piston assembly 31 to accurately position the platform 14. In the control block diagram 220, the platform 14 has a measured instantaneous platform position ("x") as measured by the measurement system 18 (illustrated in FIG. 1) (for example, along the measurement axis 30 (illustrated in FIG. 1) )).

」)、所要加速度(「

」)，及平台加速度變化率參考(「

」)；(ii)平台回饋(「FB」)控制器262；(iii)平台前饋(「FF」)控制器264；(iv)回饋轉換器266，其將回饋力命令轉換為回饋壓力命令；(v)前饋轉換器268，其將前饋力命令轉換為前饋壓力命令；(vi)第一腔室控制器270；(vii)第二腔室控制器272；及(vii)腔室體積估計器278，其基於平台14之經量測位置(「x」)來估計第一腔室之當前第一腔室體積 (「V ₁ 」)及第一體積改變率(「

」)，且基於平台14之經量測位置來估計第二腔室之當前第二腔室體積(「V ₂ 」)及第二體積改變率(「

」)。 In this embodiment, the control block diagram 220 includes: (i) a platform reference block 260, which provides a desired reference position or trajectory ("x _d ") of the platform and the platform 14 (for example, along the moving axis 30 (as shown in FIG. 1) Description)), desired speed ("

``), desired acceleration ("

”), and the platform acceleration change rate reference (“

"); (ii) Platform Feedback ("FB") Controller 262; (iii) Platform Feedforward ("FF") Controller 264; (iv) Feedback Converter 266, which converts feedback force commands into feedback pressure commands (V) a feedforward converter 268, which converts the feedforward force command into a feedforward pressure command; (vi) the first chamber controller 270; (vii) the second chamber controller 272; and (vii) the cavity The chamber volume estimator 278 estimates the current first chamber volume ("V ₁ ") and the first volume change rate ("

"), and based on the measured position of the platform 14 to estimate the current second chamber volume ("V ₂ ") and the second volume change rate ("

").

」)、平台加速度參考(「

」)、平台加速度變化率參考(「

」)饋送至產生平台前饋力命令(「F _ff 」)之平台前饋控制器264，平台前饋力命令(「F _ff 」)表示為補償諸如系統時間延遲及軌跡之事項所必要的力命令。 It should be noted that some blocks of the control block diagram 220 of FIG. 2A are optional, and/or the control block diagram 220 may include additional control blocks. For example, the control block diagram 220 can be designed without the platform feedforward controller 264 loop. Additionally or alternatively, the control block diagram 220 may be designed to include an iterative learning loop (not shown in the figure). In the control block diagram 220, when moving from left to right, compare the position or trajectory ("x _d ") of the platform to be referenced 260 with the measured position ("x") of the platform to generate the desired position of the platform 14 The platform tracking error ("e") of the error between the measured position and the measured position. Next, the platform tracking error ("e") is fed to _{the platform feedback controller 262 that generates the platform feedback force command ("F fb} "). The platform feedback force command ("F _fb ") is expressed as the self-passage of the platform 14 The force command necessary to move the measured position to the reference position. At the same time, set the desired reference position ("x _d "), the platform speed reference ("

``), platform acceleration reference ("

``), platform acceleration change rate reference ("

") is fed to the platform feedforward controller 264 that generates the platform feedforward force command ("F _ff "). The platform feedforward force command ("F _ff ") represents the force necessary to compensate for things such as system time delay and trajectory Order.

」)，及用於第二腔室之第二前饋改變率壓力命令(「

」)。 Next, in this embodiment, the platform feedback force command ("F _fb ") and the feed forward force command ("F _ff ") are combined to generate a combined force command ("F _cmd ") that is fed to the feedback converter 266 , The feedback converter 266 converts the combined force command into a first feedback pressure command ("P1 _fb " or "P _1,cmd ") for the first chamber, and a second feedback pressure command for the second chamber ("P2 _fb " or "P _2,cmd "). Similarly, the platform feedforward force command ("F _ff ") is fed to the feedforward converter 268, which converts the feedforward force command into a first feedforward rate of change pressure command for the first chamber ("

"), and the second feedforward rate of change pressure command for the second chamber ("

").

」)、第一經量測壓力(「P ₁ 」)、第一腔室體積(「V ₁ 」)及第一體積改變率(「

」)以判定被引導至第一閥子總成之第一閥子總成電流命令(「u ₁ 」)。相似地，第二腔室控制器272使用第二回饋壓力命令(「P_2,cmd」、第二前饋壓力命令(「

」)、第二經量測壓力(「P ₂ 」)、第二腔室體積(「V ₂ 」)及第二體積改變率(「

」)以判定被引導至第二閥子總成之第二閥子總成電流命令(「u ₂ 」)。至閥總成38之電流控制至活塞總成31之活塞流體且在平台14上產生力(「F」)。 Subsequently, the first chamber controller 270 uses the first feedback pressure command ("P _1,cmd ", the first feedforward pressure command ("

''), the first measured pressure ("P ₁ "), the first chamber volume ("V ₁ "), and the first volume change rate ("

_{") to determine the current command ("u 1} ") of the first valve sub-assembly that is directed to the first valve sub-assembly. Similarly, the second chamber controller 272 uses the second feedback pressure command ("P _{2, cmd} ", the second feedforward pressure command ("

”), the second measured pressure (“P ₂ ”), the second chamber volume (“V ₂ ”) and the second volume change rate (“

”) to determine the second valve sub-assembly current command ("u ₂ ") that is directed to the second valve sub-assembly. The current to the valve assembly 38 controls the piston fluid to the piston assembly 31 and generates a force ("F") on the platform 14.

As provided herein, the chamber controllers 270, 272 use the inversion of the valve characteristics to accurately determine the respective current commands necessary to accurately control the pressure in the two chambers. This procedure is described in more detail below with reference to FIG. 2B.

It should be noted that in embodiments where one valve of each valve subassembly is closed at any given time, a single current command is all required for each valve subassembly. Alternatively, if the two valves of each valve subassembly can be opened at any given time, the chamber controllers 270, 272 will need to be designed to provide individual current commands to each valve.

Several equations are useful for understanding the forces generated by the platform mover assembly 16 and for understanding the control of the platform mover assembly 16 by the control system 20. As provided above, the total force generated by the platform mover assembly 16 is provided as follows: F = F ₁ - F ₂ . Equation 1

As provided above, F is the total force; F _{1 is} the force generated by the first chamber; and F _{2 is} the force generated by the second chamber.

Equation 1 can be rewritten as follows: F = P ₁ A ₁ - P ₂ A ₂ . Equation 2

As provided above, P ₁ is the first chamber pressure in the first chamber; A ₁ is the effective piston area for the first chamber; P ₂ is the second chamber pressure in the second chamber 34B; And A ₂ is the effective piston area for the second chamber 34B.

In addition, the power on the platform can be expressed as follows:

為平台之質量塊的加速度，月

為平台速度。 In Equation 3 and elsewhere, M is the mass of the platform (including the workpiece), C is the damping coefficient,

Is the acceleration of the mass of the platform, month

Is the platform speed.

The gas equation can be expressed as follows: P _i V _i = m _i RT _i . Equation 4

In Equation 4 and elsewhere, i is the respective chamber (the first chamber ("1") or the second chamber ("2")); P _i is the pressure in the respective chamber; V _i is The volume in the respective chamber; R is the gas constant; m _i is the mass of the gas in the respective chamber; and T _i is the temperature in the respective chamber,

Equation 4 can be rewritten as follows:

為各別腔室中之壓力改變率；

為各別腔室中之體積改變率，且

為各別腔室中之質量流率。 In Equation 5 and elsewhere,

Is the rate of pressure change in each chamber;

Is the rate of volume change in each chamber, and

Is the mass flow rate in each chamber.

Equation 5 can be rewritten as a chamber pressure model as follows:

In addition, Equation 5 can be rewritten as the chamber mass flow rate control as follows:

The first volume V ₁ of the first chamber 34A can be written as a function of the platform position as follows: V ₁ = A ₁ ( x + x _{1, o} ). Equation 8

Similarly, the second volume V ₂ of the second chamber 34B can be written as a function of the platform position as follows: V ₂ = A ₂ (- x + x _{2, o} ). Equation 9

In equations 8 and 9 and elsewhere, A ₁ is the effective piston area of the first chamber; A ₂ is the effective piston area of the second chamber; X is the current position of the platform; x _{1, O} is the first chamber The cut-off length; and x _{2, O} is the cut-off length of the second chamber.

Equation 8 can be rewritten as follows:

Similarly, Equation 9 can be rewritten as follows:

為第一腔室中之體積改變率；且

為第二腔室中之體積改變率。 In these equations and elsewhere,

Is the rate of volume change in the first chamber; and

Is the rate of volume change in the second chamber.

The chamber pressure control of each chamber 34A, 34B can be expressed as follows:

F _cmd = P _{1, cmd} A ₁ - P _{2, cmd} A ₂ . Equation 13

為平台加速度參考；

為平台速度參考；

為平台加速度變化率參考，x _d 為參考位置； C 為平台與致動器系統之阻尼比； C _fb (s)為平台回饋控制濾波器；x為平台之當前經量測位置； P _1,cmd 為至第一腔室之壓力命令；且 P _2,cmd 為至第二腔室之壓力命令。 In equations 12 and 13 and elsewhere, F _cmd is the force command; F _feedforward is the feedforward force command; F _feedback is the feedback force command;

For the platform acceleration reference;

For the platform speed reference;

Is the platform acceleration change rate reference, x _d is the reference position; C is the damping ratio between the platform and the actuator system; C _fb ( s ) is the platform feedback control filter; x is the current measured position of the platform; P _{1, cmd} is the pressure command to the first chamber; and P _{2, cmd} is the pressure command to the second chamber.

Equations 12 and 13 can be rewritten as follows: P _{1, cmd} A ₁ = F _o + r . F , and equation 14

P _{2, cmd} A ₂ = F _o -(1- r ). F. Equation 15

In equations 14 and 15 and elsewhere, F _o is the offset force command; and r is the distribution ratio between the first chamber and the second chamber. In some embodiments, r has a value greater than 0 but less than 1 (0<r<1), where the nominal value is r=0.5.

Equations 14 and 15 can be rewritten as follows:

The chamber pressure control can be expressed as follows:

In addition, Equation 18 can be expressed as follows:

Similar to Equation 7, the chamber mass flow control can be expressed as follows:

為用於第一腔室及第二腔室中之一者的質量流率命令。 In Equation 21 and elsewhere,

It is a mass flow rate command for one of the first chamber and the second chamber.

」)。壓力至質量流量轉換器292接收壓力改變率命令(「

」)、腔室壓力(「P _i 」)、當前腔室體積(「V _i」)及體積改變率(「

」)，且產生用於入口閥之質量流率命令(

)及用於出口閥之質量流率命令(「

」)。壓力至質量流量轉換器292可使用本文中所提供之方程式21及22。 Figure 2B is a control block diagram illustrating how one of the chamber controllers 270, 272 (illustrated in Figure 2A) can be configured. In this embodiment, the chamber controller includes: (i) pressure feedback controller 290; (ii) pressure to mass flow converter 292; (iii) inlet mass flow to orifice area converter 294; (iv) outlet Mass flow to orifice area converter 296; (v) inlet orifice area to current converter 297; and (vi) outlet orifice area to current converter 298. In this embodiment, the pressure feedback controller 290 receives the pressure error P _i,err for each chamber, and generates a pressure change rate feedback ("

"). The pressure-to-mass flow converter 292 receives the pressure change rate command ("

``), chamber pressure (" P _i "), current chamber volume (" V _i "), and volume change rate ("

"), and generate a mass flow rate command for the inlet valve (

) And the mass flow rate command for the outlet valve ("

"). The pressure to mass flow converter 292 can use equations 21 and 22 provided herein.

」)及腔室壓力(「P _i 」)，且產生用於入口閥之入口孔口面積命令(「a _i,cmd+」)。入口質量流量至孔口面積轉換器294可使用本文中所提供之方程式24。稍微相似地，出口質量流量至孔口面積轉換器296接收質量流率命令(「

」)及腔室壓力(「P _i 」)，且產生用於出口閥之出口孔口面積命令(「a _i,cmd-」)。出口質量流量至孔口面積轉換器296可使用本文中所提供之方程式25。 The inlet mass flow to orifice area converter 294 receives the mass flow rate command ("

") And chamber pressure (" P _i "), and generates the command area of the inlet opening of the inlet valve used (" a _{i, cmd +} "). The inlet mass flow to orifice area converter 294 can use Equation 24 provided herein. Slightly similarly, the outlet mass flow to orifice area converter 296 receives the mass flow rate command ("

") and the chamber pressure (" P _i "), and generate the output orifice area command (" a _{i , cmd-} ") for the outlet valve. The outlet mass flow to orifice area converter 296 can use Equation 25 provided herein.

Next, the area of the inlet orifice to-current converter 297 using commands inlet aperture area ( "a _{i, cmd +")} to generate a current command for the inlet valve of the inlet ( "u _{i, cmd} +"). The inlet orifice area to current converter 297 can use Equation 27 provided herein. Similarly, the outlet orifice area to current converter 298 uses the outlet orifice area command (" a _{i , cmd-} ") to generate the outlet current command (" u _{i , cmd-} ") for the outlet valve. The exit orifice area to current converter 298 can use Equation 28 provided herein.

Figure 3 is a simplified illustration of a piston chamber 334i and a valve subassembly 338i. As illustrated in FIG. 3, in this embodiment, the chamber mass flow rate commands entering and leaving the chamber 334i are controlled by the inlet valve 338ii and the outlet valve 338io. In this embodiment, the pressure source 346 provides the pressurized piston fluid 340 at a pressure called P _{source to the inlet of the inlet valve 338ii.} In addition, the outlet of the outlet valve 338io is at the pressure of P _drain. The chamber mass flow control of Equation 21 can be rewritten as follows:

為用於所選擇腔室334i之入口閥338ii的質量流率命令；且

為用於所選擇腔室334i之出口閥338io的質量流率命令。如本文中所提供，在某些實施例中，若需要增加進入腔室334i之質量流率(

0)，則將出口閥338io閉合(

)且將質量流率命令設定為等於入口閥338ii之質量流率命令(

)。相似地，在某些實施例中，若需要增加離開腔室334i之質量流率(

<0)，則將入口閥338ii閉合(

)且將質量流率命令設定為等於出口閥338io之質量流率命令(

)。 In Equation 22 and elsewhere,

Is the mass flow rate command for the inlet valve 338ii of the selected chamber 334i; and

Is the mass flow rate command for the outlet valve 338io of the selected chamber 334i. As provided herein, in certain embodiments, the mass flow rate into the chamber 334i (

0), then close the outlet valve 338io (

) And set the mass flow rate command equal to the mass flow rate command of the inlet valve 338ii (

). Similarly, in some embodiments, if it is necessary to increase the mass flow rate leaving the chamber 334i (

<0), then close the inlet valve 338ii (

) And set the mass flow rate command equal to the mass flow rate command of the outlet valve 338io (

).

The valve flow equation can be written as follows:

In Equation 23 and elsewhere, a is the area of the open valve orifice; f is a mathematical function; P _upstream is the upstream pressure of the valve orifice; and P _downstream is the downstream pressure of the valve orifice. Therefore, the mass flow rate is equal to the area of the open valve orifice multiplied by a function of the upstream pressure and the downstream pressure.

Figure 4 is a simplified illustration of a pipeline 400 that includes an orifice 402, which is similar to the valve orifice when the valve is open. In this example, the upstream pressure and the downstream pressure are marked, and the orifice 402 has an orifice area. Referring to Figures 3 and 4, Equation 23 can be rewritten as the following valve orifice area command:

In these equations and elsewhere, a _{i , cmd} + are the valve orifice commands for the inlet valve 338ii of the selected chamber 334i; and a _{i , cmd} -are the outlet valve 338io for the selected chamber 334i The mass flow rate command.

The valve area equation can be written as follows: a = A ( u ). Equation 26

In Equation 26, a is the valve orifice area; A is the valve area equation; and u is the valve current. The valve area equation is described in more detail below.

Equation 26 can be rewritten as a valve current command as follows:

為用於入口閥之閥面積方程式之反轉；a _i,cmd+為入口閥之閥孔口面積；u _i,cmd-為至出口閥之閥電流命令；

為用於出口閥之閥面積方程式之反轉；且a _i,cmd-為出口閥之閥孔口面積。 In equations 27 and 28 and elsewhere, u _{i , cmd +} are the valve current commands to the inlet valve;

Is the reversal of the valve area equation for the inlet valve; a _{i , cmd +} is the valve orifice area of the inlet valve; u _{i , cmd -} is the valve current command to the outlet valve;

Is the reversal of the valve area equation for the outlet valve; and a _{i , cmd -} is the valve orifice area of the outlet valve.

Equations 24 and 25 can be written more generally as follows:

θ)，則

For subsonic flow, the upstream pressure divided by the downstream pressure is less than or equal to the stopt (" θ ") (

θ ), then

>θ)時，則f(P _u ,P _d )=βP _u 。 方程式31 For subsonic flow, when the upstream pressure divided by the downstream pressure is greater than the stopt (" θ ") (

> θ ), then f ( P _u , P _d ) = βP _u . Equation 31

；

；且

，其中 c 為排放係數； M _m 為氣體分子質量；Z為氣體可壓縮性因子；k為比熱比；R為通用氣體定律常數；且T為溫度。 In these equations,

；

;and

, Where c is the emission coefficient; M _m is the mass of gas molecules; Z is the gas compressibility factor; k is the specific heat ratio; R is the general gas law constant; and T is the temperature.

FIG. 5A is a simplified cross-sectional view of a non-exclusive example of a valve 538 that can be used as one of the valves 38C, 38D, 38E, and 38F from FIG. 1. In this embodiment, the valve 538 is a poppet valve, which includes a valve housing 539A, a movable valve body 539B, an inlet duct 539C, an outlet duct 539D, and an elastic member 539E that pushes the valve body 539B against the inlet duct 539C (for example, Spring), and solenoid 539F.

In this simplified example, the valve housing 538A has a slightly cylindrical shape, the valve body 539B has a disc shape, and the ducts 539C, 539D have a tubular shape. In addition, in FIG. 5A, the valve 538 is illustrated as being in position when the control system (not shown in FIG. 5A) is not directing current to the solenoid 539F Closed position. Thus, the elastic member 539E pushes the valve body 539B against the top of the inlet duct 539C to close the valve 538.

It should be noted that when current is not directed to the solenoid 539F, the valve remains closed as long as the spring preload force is greater than the force generated by the pressure difference between the upstream pressure and the downstream pressure.

Fig. 5B is a simplified cross-sectional view of the valve 538 of Fig. 5A, wherein the valve 538 is in an open position. At this time, the control system (not shown in Figure 5B) is directing current to solenoid 539F. When the current is directed to the solenoid, this generates a solenoid force F _{solenoid that} pushes (attracts) the valve body 539B upward away from the top of the inlet duct 539C. Typically, the magnitude of the solenoid force is proportional to the current. When sufficient current is guided to the solenoid 539F, the spring preload force of the elastic member 539F is overcome, the valve body 539B is moved away from the top of the inlet duct 539C, and the valve 538 is opened. In addition, the amount of current will determine how far the valve 538 is opened. Generally, the size of the valve opening increases as the current increases.

As illustrated in FIG. 5B, the amount by which the valve body 539B has moved from the closed position to the open position is referred to as "y".

Figure 5C is a simplified cross-sectional view of the valve 538 of Figure 5A, where the inlet duct 539C is removed, the solenoid 539F is not activated, and there is no pressure in the ducts 539C, 539D. At this time, the elastic member 539B pushes down the valve body 539E preload distance y _o. The valve body 539B is illustrated as being in a closed position in the form of a reference hypothesis. When the inlet conduit 539D in place (as illustrated in FIG. 5A), the resilient member 539E is applied to the elastic member 539E of equal spring constant k _s is multiplied by the preload force of the preload spring in the distance y _o.

The control of valve 538 can be expressed as follows

為閥體539B之加速度； C _v 為由彈簧摩擦造成之阻尼；

為閥體539B之速度；k _s 為彈性構件539E之彈簧常數；y _o 為預負載距離；k _f 為螺線管力常數；u為被引導至螺線管之電流命令；r為入口導管539C之頂部處的半徑；差量壓力(delta pressure)為上游壓力與下游壓力之間的差(△P = P _u - P _d )。 In Equation 32 and elsewhere, M _v is the mass of the valve body 539B;

Is the acceleration of the valve body 539B; C _{v is} the damping caused by spring friction;

Is the speed of the valve body 539B; k _s is the spring constant of the elastic member 539E; y _o is the preload distance; k _f is the solenoid force constant; u is the current command guided to the solenoid; r is the inlet duct 539C The radius at the top; delta pressure is the difference between the upstream pressure and the downstream pressure ( △ P = P _u - P _d ).

The effective orifice area "a" of the valve 538 illustrated in FIGS. 5A to 5C can be expressed as follows:

In Equations 33 and 34 and elsewhere, A is the valve area equation; and A ^-1 is the inverse of the valve area equation.

It can be expressed as the cut-off area current u _o necessary to overcome the spring preload force as follows:

In the case of a valve 538 illustrated in the FIGS. 5A to 5C, the following may be expressed in a case where no leak maximum allowable differential pressure △ P _max:

In the case of the valve 538 illustrated in FIGS. 5A to 5C, the static control current can be expressed as follows:

As provided above, in order to accurately control the fluid actuator assembly 24, it is critical to determine the non-linearity embedded in each of the valves 38C, 38D, 38E, 38F. In some embodiments, each valve 38C, 38D, 38E, 38F is not disassembled to identify the valve characteristics of each valve 38C, 38D, 38E, 38F. Instead, each physical valve 38C, 38D, 38E, and 38F of the valve assembly 24 is tested to determine its individual valve characteristics. For example, for each valve 38C, 38D, 38E, 38F, various valve current commands and various inlet/outlet pressure differences are used to measure the flow rate. Subsequently, for each valve 38C, 38D, 38E, 38F, the effective orifice area can be calculated from the flow rate information using the flow equation (see equations 24 to 31).

Figure 6A is a graph illustrating the effective orifice area of the valve versus current command for various differential pressures ("△ P"). This pattern is generated by experimentally testing the poppet valve under various differential pressures. For example, while maintaining a differential pressure of 350 kPa, the flow rate is measured under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small box in FIG. 6A. Then, line 600A is generated by curve fitting these data points. The line 600A represents the relationship between the valve area orifice versus the current command for a differential pressure of 350 kPa.

Next, while maintaining a differential pressure of 300kPa, measure the flow rate under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small circle in FIG. 6A. Subsequently, a line 602A is generated by curve fitting these data points. Line 602A represents the valve area orifice for the differential pressure of 300kPa The relationship between the current commands.

Next, while maintaining the differential pressure of 250kPa, measure the flow rate under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small "x" in FIG. 6A. Subsequently, a line 604A is generated by curve fitting these data points. Line 604A represents the relationship between the valve area orifice versus current command for a differential pressure of 250 kPa.

In addition, while maintaining a differential pressure of 200kPa, the flow rate is measured under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small "z" in FIG. 6A. Subsequently, line 606A is generated by curve fitting these data points. Line 606A represents the relationship between the valve area orifice versus the current command for a differential pressure of 200 kPa.

In addition, while maintaining the differential pressure of 150kPa, the flow rate is measured under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small triangle in FIG. 6A. Subsequently, line 608A is generated by curve fitting these data points. The line 608A represents the relationship between the valve area orifice and the current command for a differential pressure of 150 kPa.

In addition, while maintaining a differential pressure of 100kPa, the flow rate is measured under a plurality of different current commands to the solenoid. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small "+" in FIG. 6A. Subsequently, a line 610A is generated by curve fitting these data points. The line 610A represents the relationship between the valve area orifice versus the current command for a differential pressure of 100 kPa.

Finally, when maintaining the differential pressure of 50kPa, the Measure the flow rate under different current commands. Subsequently, the effective orifice area is calculated for each measured flow rate, and the effective orifice area is plotted as a small "D" in FIG. 6A. Subsequently, a line 612 is generated by curve fitting these data points. Line 612 represents the relationship between the valve area orifice and the current command for a differential pressure of 50 kPa.

In this example, the valve characteristic 614 of this valve represents the relationship between the effective valve orifice area and the current command for several different differential pressures. Alternatively, for example, the valve characteristic 614 may be each of the following: (i) the relationship between the effective valve orifice area and the voltage for several different differential pressures; (ii) the relationship between the effective valve orifice area and the voltage for several different differential pressures; The relationship between flow rate and current command; and/or (iii) the relationship between flow rate and voltage for several different differential pressures.

As provided above, in certain embodiments, the valve characteristic 614 is inverted to produce an inverted valve characteristic 616 that is then used to control the other valve. For example, the data in FIG. 6A can be inverted (switching the X and Y axes of the graph) to produce the inverted valve characteristic 616 illustrated in FIG. 6B.

More specifically, FIG. 6B is a graph illustrating the valve current command to the effective orifice area, which is the inverse of the graph in FIG. 6A. In this example, the data from FIG. 6A is inverted to generate the data in FIG. 6B. Subsequently, curve fitting was used to generate the curve in Figure 6B.

For example, under a differential pressure of 350kPa, the data is represented as a small box. Then, line 600B is generated by curve fitting these data points. Line 600B represents the relationship between the valve current command for a differential pressure of 350 kPa and the valve area orifice.

Next, under a differential pressure of 300kPa, the data is represented as a small circle. Subsequently, a line 602B is generated by curve fitting these data points. Line 602B represents the relationship between the valve current command for a differential pressure of 300 kPa and the valve area orifice.

Similarly, under a differential pressure of 250kPa, the data is expressed as a small "x's". Then, line 604B is generated by curve fitting these data points. Line 604B represents the relationship between the valve current command for a differential pressure of 250 kPa and the valve area orifice.

In addition, under a differential pressure of 200kPa, the data is expressed as a small "z's". Subsequently, line 606B is generated by curve fitting these data points. Line 606B represents the relationship between the valve current command for a differential pressure of 200 kPa and the valve area orifice.

In addition, under a differential pressure of 150kPa, the data is represented as a small triangle. Subsequently, line 608B is generated by curve fitting these data points. The line 608B represents the relationship between the valve current command for the differential pressure of 150 kPa and the valve area orifice.

In addition, under the differential pressure of 100kPa, the data is expressed as small "+'s". Subsequently, a line 610B is generated by curve fitting these data points. Line 610B represents the relationship between the valve current command for a differential pressure of 100 kPa and the valve area orifice.

Finally, under the differential pressure of 50kPa, the data is expressed as small "D's". Subsequently, line 612B is generated by curve fitting these data points. Line 612B represents the relationship between the valve current command for a differential pressure of 50 kPa and the valve area orifice.

It should be noted that the reversal valve characteristic 616 data from the graph in Figure 6B can be used by the control system to accurately control the valve. It should also be noted that the control system can use interpolation to generate data for other differential pressures to accurately control the valve at other differential pressures.

7A to 7D are simplified cross-sectional illustrations of another type of valve 738 at various valve positions. The valve 738 can be used as one of the valves 38C, 38D, 38E, and 38F from FIG. 1. More specifically, Figure 7A is a simplified side view illustration of the spool type valve 738 at the fully closed position; Figure 7B is a simplified side view illustration of the spool type valve 738 at the closed baseline (ready to open) position; 7C is a simplified side view illustration of the spool type valve 738 in the partially open position; and FIG. 7D is the A simplified side view illustration of the spool type valve 738 in the fully open position.

In this embodiment, the valve 738 is a spool type valve, which includes a valve housing 739A, a movable valve body 739B (sometimes referred to as a "sliding shaft"), an inlet opening (not shown in the figure), and an outlet opening 739D , Push the elastic member 739E (such as a spring) of the valve body 739B from right to left, and move the solenoid 739F of the valve body 739B from left to right.

In this simplified example, the valve housing 738A has a slightly hollow cylindrical shape, the valve body 739B has a disc shape, and the opening 739D has a circular shape and is positioned on the opposite side of the valve housing 738A, wherein the valve body 739B is positioned on the opposite side of the valve housing 738A. Between opposite sides.

It should be noted that because the upstream pressure and the downstream pressure are orthogonal to the valve body 739B, the differential pressure will not affect the opening or closing of the valve 738.

Additionally, in FIG. 7A, the valve 738 is illustrated as being in a fully closed position when the control system (not shown in FIG. 7A) is not directing current to the solenoid 739F. At this time, the valve body 739B covers both the inlet and the outlet 739D to close the valve 738.

Figure 7B is a simplified cross-sectional view of the valve 738 of Figure 7A, where the valve 738 is in a baseline position just before it opens. At this time, the control system (not shown in Figure 7B) is directing current to solenoid 739F. When the current is directed to the solenoid, this generates a solenoid force F _solenoid that pushes the valve body 739B to the baseline position y _b where the valve 738 is about to open.

FIG. 7C is a simplified cross-sectional view of the valve 738 of FIG. 7A, wherein the valve 738 is in a partially open position. At this time, the control system (not shown in Figure 7C) is directing current to solenoid 739F. When the current is directed to the solenoid, this generates a solenoid force F _solenoid that pushes the valve body 739B to the position y where the valve 738 is partially opened.

Typically, the magnitude of the solenoid force is proportional to the current. When directing enough current When it reaches the solenoid 739F, it will overcome the spring preload force of the elastic member 739F and move the valve body 739B. In addition, the amount of current will determine how far the valve 738 is opened. Generally, the size of the valve opening increases as the current increases.

Figure 7D is a simplified cross-sectional view of the valve 738 of Figure 7A with the valve 738 in a full position.

In this embodiment, the valve mechanical dynamics for the valve 738 illustrated in FIGS. 7A to 7D can be expressed as follows:

為閥體739B之加速度；c _v 為由彈簧摩擦造成之阻尼；

為閥體739B之速度；k _s 為彈性構件739E之彈簧常數；y _o 為預負載距離；k _f 為螺線管力常數；u為被引導至螺線管之電流命令；且f _preload 為彈性構件739E之預負載力。 In Equation 38 and elsewhere, M _V is the mass of the valve body 739B;

Is the acceleration of the valve body 739B; c _{v is} the damping caused by spring friction;

Is the speed of the valve body 739B; k _s is the spring constant of the elastic member 739E; y _o is the preload distance; k _f is the solenoid force constant; u is the current command guided to the solenoid; and f _preload is the elasticity Preload force of member 739E.

Figure 7E is a simplified illustration of the outlet 739D and the valve body 739B in a partially open position that helps explain the effective orifice area. In this example, χ = y _o + y . _{In addition, the effective orifice area A eff of} this type of valve 738 can be calculated as follows:

8A is a graph illustrating the normalized effective orifice area versus the normalized sliding shaft position calculated using the above formula for the valve illustrated in FIGS. 7A to 7D. In this example, the valve characteristic 814 of this valve represents the relationship between the normalized effective orifice area and the normalized spool position.

As provided above, in certain embodiments, the valve characteristic 814 is reversed to produce the reverse valve characteristic 816 illustrated in FIG. 8B that is then used to control the other valve. For example, the data in FIG. 8A can be inverted (switching the X and Y axes of the graph) to generate the inverted valve characteristic 816 that plots the sliding axis position versus the normalized effective orifice area illustrated in FIG. 8B.

Some valves (such as spool valves) have backlash-like hysteresis. In these valves, for the same current command, the spool position may be different depending on the previous command history.

Figure 9A is a graph illustrating the test results of the spool valve. In Figure 9A, the graph illustrates the sliding axis position versus voltage. In addition, FIG. 9B is a graph illustrating the simulation result of the spool valve. In Figure 9B, the graph illustrates the sliding axis position versus current. These diagrams illustrate that for the same current command (or voltage command), the position of the sliding shaft can be different depending on the previous command history. For example, referring to FIG. 9A, for the same command (for example, 5 volts), the position of the sliding axis will be different depending on the previous command. Similarly, referring to FIG. 9B, for the same command (for example, 0.5 ampere), the position of the sliding shaft will be different depending on the previous command.

As provided herein, referring to FIG. 9A, another valve characteristic 914 of this valve is represented by the relationship between the position of the spool shaft and the voltage. Referring to FIG. 9B, another valve characteristic 915 of this valve is represented by the relationship between the position of the spool shaft and the current. Therefore, as provided in this article, spool valve nonlinearities (backlash and effective orifice geometry) can be calibrated and modeled. Later, its inversion can be applied to the control software to linearize the spool valve.

The method used to calculate the backlash of the valve can vary. In one embodiment, the calibration can be performed by gradually increasing the current (or voltage) command from zero to the maximum value and then gradually reducing it to zero while monitoring the position of the valve body. Then the current (or voltage) command is used as a compensation map for the position data of the sliding shaft.

In certain embodiments, the baseline may be determined during calibration of the position of the valve backlash y _o. The baseline position can be determined by slightly increasing the current command when checking the outlet flow of the valve to determine when the orifice begins to open.

Figure 10A illustrates the two valve characteristics of the spool valve. More specifically, FIG. 10A includes: (i) a first valve characteristic 1014, such as a graph illustrating a normalized effective orifice area versus a normalized spool position; and (ii) a second valve characteristic 1015, such as a spool position The graph of current. The data used for the graphics 1014 and 1015 can be obtained or calculated experimentally.

As provided above, in certain embodiments, the valve characteristics 1014, 1015 are reversed to produce the reverse valve characteristics 1016, 1017 that are subsequently used to control the other valve as illustrated in FIG. 10B. For example, invert the data from the graph 1014 (switch the X and Y axes of the graph) to generate a graph 1016 that plots the normalized sliding axis position versus the normalized effective orifice area. In addition, the data from the graph 1015 is inverted (the X and Y axes of the graph are switched) to generate a graph 1017 that plots the position of the current versus the sliding axis. As provided herein, the reversal valve features 1016, 1017 help to accurately control the effective orifice area of the valve regardless of the valve's non-linearity.

It should be noted that the reversal valve characteristics 1016, 1017 may be in the form of look-up tables, maps, graphs, charts, or analytical models or fitting models.

FIG. 11 is a schematic diagram illustrating an exposure apparatus 1170 used in the present invention. Exposure equipment 1170 includes equipment frame 1172, lighting system 1182 (irradiation equipment), mask platform assembly 1184, optical assembly 1186 (lens assembly), plate platform assembly 1110, and control mask platform assembly 1184 and plate The control system 1120 of the platform assembly 1110.

The exposure equipment 1170 is particularly useful as a lithography device for transferring the pattern (not shown in the figure) of the liquid crystal display device from the mask 1188 to the workpiece 1122.

The equipment frame 1172 is rigid and supports the components of the exposure equipment 1170. The design of the equipment frame 1172 can be changed to suit the design requirements for the rest of the exposure equipment 1170.

The illumination system 1182 includes an illumination source 1192 and an illumination optical assembly 1194. The illumination source 1192 emits a beam of light energy (irradiation). The illumination optics assembly 1194 guides the light energy beam from the illumination source 1192 to the shield 1188. The beam selectively illuminates different parts of the mask 1188 and exposes the workpiece 1122.

The optical assembly 1186 projects and/or focuses the light transmitted through the mask 1188 to the workpiece 1122. Depending on the design of the exposure device 1170, the optical assembly 1186 can magnify or reduce the image illuminated on the mask 1188.

The mask platform assembly 1184 holds and positions the mask 1188 relative to the optical assembly 1186 and the workpiece 1122. Similarly, the plate platform assembly 1110 holds and positions the workpiece 1122 relative to the projected image of the illuminated portion of the mask 1188.

There are several different types of lithography devices. For example, the exposure device 1170 can be used as a scanning type photolithography system, which exposes a pattern from a mask 1188 to a glass workpiece 1122, wherein the mask 1188 and the workpiece 1122 move synchronously. Alternatively, the exposure device 1170 may be a step and repeat type photolithography system that exposes the mask 1188 when the mask 1188 and the workpiece 1122 are stationary.

However, the use of the exposure equipment 1170 and the platform assembly provided herein is not limited to the photolithography system used in the manufacture of liquid crystal display devices. For example, the exposure equipment 1170 can be used as a semiconductor photolithography system, which exposes integrated circuit patterns onto a wafer or a photolithography system for manufacturing thin film magnetic heads. In addition, the present invention can also be applied to a proximity photolithography system, which exposes the mask pattern by positioning the mask and the substrate closely without using the lens assembly. In addition, the present invention provided herein can be used in other devices, including other flat panel display processing equipment, Elevators, machine tools, metal cutting machines, inspection machines and disk drives.

The photolithography system according to the above-mentioned embodiment can be constructed by assembling various subsystems (including each component listed in the scope of the attached patent application) so as to maintain the specified mechanical accuracy, electrical accuracy and Optical accuracy. In order to maintain various accuracy levels, before and after assembly, each optical system is adjusted to achieve its optical accuracy. Similarly, adjust each mechanical system and each electrical system to achieve its respective mechanical and electrical accuracy. The procedure for assembling each sub-system into the photolithography system includes the mechanical interface, circuit wiring connection and air pressure pipe connection between each sub-system. Needless to say, there is also a procedure for assembling each subsystem before assembling the photolithography system from the various subsystems. Once the photolithography system is assembled using various subsystems, overall adjustments are performed to ensure that accuracy is maintained throughout the photolithography system. In addition, the exposure system needs to be manufactured in a clean room where the temperature and cleanliness are controlled.

In addition, the above-mentioned system can be used to fabricate the device by the procedure generally shown in FIG. 12. In step 1201, the function and performance characteristics of the device are designed. Next, in step 1202, a mask (mask) with a pattern is designed according to the previous design steps, and a glass plate is manufactured in a parallel step 1203. In step 1204, the mask pattern designed in step 1202 is exposed to the glass plate from step 1203 by the photolithography system described above according to the present invention. In step 1205, the flat panel display device is assembled (including the cutting procedure, the bonding procedure and the packaging procedure), and finally, the device is inspected in step 1206.

Although the specific assembly as shown and disclosed herein can fully achieve the objectives and provide the advantages stated above, it should be understood that it only illustrates the presently preferred embodiments of the present invention, and is in addition to the scope of the attached patent application Except for the content described in, it is not intended to limit the construction or design details shown in this article.

10: Platform assembly

12: Base

14: Platform

16: Platform mover assembly

18: Measurement system

20: Control system

20A: processor

20B: Electronic data storage

22: Workpiece

24: Fluid actuator assembly

26: Pedestal mounting table

28: Bearing assembly

30: moving axis

31: Piston assembly

32: Piston housing

32A: Tubular side wall

32B: Disc-shaped first end wall

32C: Disc-shaped second end wall

32D: Wall pores

34: Piston chamber

34A: first chamber

34B: second chamber

36: Piston

36A: Piston axis

36B: Piston body

36C: Piston seal

36D: The first beam

36E: second beam

38: valve assembly

38A: First valve sub-assembly

38B: Second valve sub-assembly

38C: First inlet valve

38D: First outlet valve

38E: second inlet valve

38F: second outlet valve

40: Piston fluid

42: Piston mounting table

44: Total force (F)

46: fluid pressure source

46A: fluid storage tank

46B: Compressor

46C: Pressure regulator

Claims (7)

A platform assembly for positioning a workpiece along a moving axis. The platform assembly includes: a platform adapted to be coupled to the workpiece; a fluid actuator assembly coupled to the platform and To move the platform along the moving axis, the fluid actuator assembly includes: a piston housing defining a piston chamber; a piston positioned in the piston chamber and relative to the piston along a piston axis The piston chamber moves; and a valve assembly that controls the flow of a piston fluid into the piston chamber; a control system that controls the valve assembly to control the flow of the piston fluid into the piston chamber, wherein The valve assembly includes a housing and a first inlet valve. The first inlet valve is formed in the housing and is arranged to cover an outlet opening. The piston fluid in the housing flows into the piston cavity through the outlet opening. Chamber, and an elastic member that controls the opening and closing amount of the outlet opening through the first inlet valve; and the control system controls the valve assembly, wherein the control system uses an inverse function of the first inlet valve characteristic The first inlet valve characteristic is the relationship between the valve position and the current command sent to the elastic member to control the above-mentioned opening and closing amount, and the first inlet valve is calibrated when the first inlet valve opens and closes the outlet opening. The characteristic difference of the inlet valve is one of the characteristics to control the valve assembly. For example, the platform assembly of item 1 of the scope of patent application, wherein the piston separates the piston chamber into a first chamber and a second chamber on opposite sides of the piston; and wherein the valve assembly controls the Piston fluid enters the flow of the first chamber and the second chamber. For example, the platform assembly of item 2 of the scope of patent application, wherein the valve assembly controls the flow of the piston fluid out of the first chamber and the second chamber. For example, the platform assembly of item 3 of the scope of patent application, wherein the valve assembly includes: (i) the first inlet valve, which controls the flow of the piston fluid into the first chamber; (ii) a first outlet Valve, which controls the flow of the piston fluid out of the first chamber; (iii) a second inlet valve, which controls the flow of the piston fluid into the second chamber; and (iv) a second outlet valve , Which controls the flow of the piston fluid out of the second chamber. For example, the platform assembly of item 4 of the scope of patent application, wherein the first outlet valve has a first outlet valve characteristic, the second inlet valve has a second inlet valve characteristic, and the second outlet valve has a second outlet Valve characteristics; and the control system also uses an inverse function of the first outlet valve characteristic, an inverse function of the second inlet valve characteristic and an inverse function of the second outlet valve characteristic to control the valve assembly. An exposure equipment includes an illumination source and a platform assembly according to any one of items 1 to 5 in the scope of patent application, the platform assembly moves the platform relative to the illumination system. A process for manufacturing a device includes the following steps: providing a substrate; and forming an image on the substrate by using the exposure equipment as in the sixth patent application.

Images