Servo control of hoisting equipment and method of use

Abstract

Embodiments of a lift apparatus and system are disclosed herein, the system including a support and at least one lift apparatus to move a substrate between the support and a transfer plane using a servo control system. Methods for servo control of a lift apparatus and lifting a substrate off of or lowering a substrate onto a support are also disclosed herein.

Description

Technical Field

[0001] This disclosure generally relates to the fields of robotics and systems and methods for servo control of lifting apparatus. Background Technology

[0002] Semiconductor substrates are typically processed in vacuum processing systems. These systems include one or more chambers, each performing substrate processing operations such as etching, chemical vapor deposition, or physical vapor deposition. These operations may include heating or cooling of the substrate and may include plasma to assist the process. Typically, the environment within such processing chambers is maintained at low, sub-atmospheric pressures. Each chamber includes inlets and outlets for venting equipment and receiving process gases, as well as orifices controlled by slit valves for receiving substrates. Such processing chambers may communicate with substrate transfer chambers, and substrate transfer chambers may have valve-controlled orifices through which substrates can be received from outside the system.

[0003] The transfer of substrates into and from the chamber, and the transfer of substrates to and from the outside of the system, are typically performed mechanically by a robotic arm with a substrate holding component (e.g., a blade or end effector) at its end. To facilitate sliding of the robotic arm's blade end under the substrate, one or more lifting rods raise the substrate approximately 20 mm to 50 mm above a tool (e.g., a suction cup assembly). The lifting rods can be pneumatically driven. This is achieved using full-stroke actuation of a solenoid valve, giving the lifting rod two positions: up and down. There can be a distance of 30 mm to 40 mm between the up and down positions of the lifting rod. To transfer the substrate to the end effector of the robotic arm, the lifting rod is extended to the up position (e.g., 20 mm to 40 mm), positioning the end effector below the substrate, and then the lifting rod is lowered to the down position, transferring the substrate to the end effector during the process. The robotic arm can then remove the substrate from the process chamber. However, this transfer process is inefficient because the substrate extends far above the terminal actuator and then far below it, which takes time to complete.

[0004] Using a fully actuated lifting rod can also damage the substrate, especially when removing it from a support such as an electrostatic chuck. After completing a process step, the pneumatic lifting mechanism raises the lifting rod to elevate the substrate above the support so that it can be removed from the chamber by a robotic arm. When the support is an electrostatic chuck, the substrate must be "de-adsorbed" before the lifting rod can raise it; that is, the electrostatic forces holding the substrate on the chuck must be removed. Traditionally, the adsorption voltage source is turned off, and both the adsorption electrodes and the substrate are grounded to remove the corresponding charges that accumulate on the adsorption electrodes and the substrate during the application of the adsorption voltage. However, this conventional de-adsorption method cannot successfully remove all the electrostatic attraction between the substrate and the chuck before the lifting rod attempts to lift the substrate from the chuck, and the substrate may stick to the chuck. When the lifting rod is actuated, the substrate may crack or break and / or pop out of the chuck to a position that is difficult for the substrate transfer robot to properly retrieve and align. In some cases, the robotic arm collides with an misaligned substrate, further damaging the robotic arm. Substrate adhesion can occur even when the support is not an electrostatic chuck, for example, when the support is a base with sputtered material buildup that causes substrate adhesion. All of these issues can lead to process downtime and financial costs for equipment repair. Summary of the Invention

[0005] According to an embodiment, a lifting device is disclosed herein for conveying a substrate between a support member and a conveying plane. The lifting device includes: a lifting rod assembly, the lifting rod assembly including: a lifting rod configured to move the substrate between the support member and the conveying plane; at least one pneumatic actuator including a moving member configured to provide a load to the lifting rod; at least one proportional pneumatic valve configured to control the fluid flow rate between the at least one pneumatic actuator and a pressurized fluid source or vent; a plurality of pressure sensors, each of the plurality of pressure sensors configured to independently measure the pressure in a corresponding supply line of the at least one pneumatic actuator; and at least one position sensor configured to measure the position of the member; and a servo control system communicating with the lifting rod assembly.

[0006] According to an embodiment, this document further discloses a method comprising the following steps: receiving a first pressure measurement result from a first pressure sensor, the first pressure sensor measuring the pressure in a first chamber of a pneumatic actuator by a controller; receiving a second pressure measurement result from a second pressure sensor, the second pressure sensor measuring the pressure in a second chamber of the pneumatic actuator by a controller; receiving a position measurement result from a position sensor, the position sensor measuring the position of a moving member of the pneumatic actuator by a controller; generating a control signal based on the first pressure measurement result, the second pressure measurement result, and the position measurement result; transmitting the control signal to at least one proportional pneumatic valve of a servo control system to control pressurized fluid to the pneumatic actuator; and operating the servo control system to extend at least one lifting rod and lift a base plate from a support via said at least one lifting rod.

[0007] According to various embodiments, this document further discloses a method comprising the steps of: operating a servo control system to lift a substrate from a substrate support, wherein the servo control system is configured to control a lifting rod assembly for lifting the substrate, comprising the steps of: actuating at least one proportional pneumatic valve to allow gas flow through a first gas line into a first chamber of a pneumatic actuator of the lifting rod assembly, and through a second gas line into a second chamber of the pneumatic actuator; measuring pressure in the first gas line using a first pressure sensor, and measuring pressure in the second gas line using a second pressure sensor; measuring the position of a moving member of the pneumatic actuator using a position sensor; controlling at least one proportional pneumatic valve using the servo control system to apply a contact force of about 2N to about 10N to the substrate through the moving member; and lifting the substrate from the support by means of a lifting rod, the lifting rod being operable to receive a load through the moving member. Attached Figure Description

[0008] The present disclosure is illustrated by way of example and not limitation in the accompanying drawings, in which the same reference numerals indicate similar elements.

[0009] Figure 1 The processing chamber, including the lifting rod assembly, is depicted.

[0010] Figure 2 A lifting rod assembly is depicted according to various embodiments.

[0011] Figure 3 Depicts lifting booms according to various implementation methods.

[0012] Figure 4 Depicts lifting booms according to various implementation methods.

[0013] Figure 5 Describe a servo control system according to an implementation method.

[0014] Figure 6 The illustration shows a method for transferring a substrate between a support and a transfer chamber according to various embodiments.

[0015] Figure 7 The illustration shows a method of controlling a lifting device using a servo control system according to various implementation methods.

[0016] Figure 8 The illustration shows a method for transferring a substrate from a process chamber to a transfer chamber using a robotic arm connected to a servo-controlled lifting rod assembly, according to various implementation methods. Detailed Implementation

[0017] Throughout this specification, references such as "one embodiment," "some embodiments," "one or more embodiments," or "an embodiment" mean that a particular feature, structure, material, or characteristic associated with that embodiment is included in at least one embodiment of this disclosure. Therefore, phrases such as "in one or more embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing in various places throughout this specification do not necessarily refer to the same embodiment of this disclosure. Furthermore, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0018] As used herein, the singular forms “a,” “the,” and “the” include plural references unless the context clearly indicates otherwise. Thus, for example, a reference to “lifting pole” includes both a single lifting pole and more than one lifting pole.

[0019] As used herein, the term “about” in relation to a measured quantity refers to the normal variation in a measured quantity that would be expected by a person skilled in the art when performing the measurement and exercising a degree of care commensurate with the purpose of the measurement and the accuracy of the measuring equipment. In some embodiments, the term “about” includes the listed number ± 10%, such that “about 10” would include numbers from 9 to 11.

[0020] The term "at least about" in relation to a measured quantity refers to the normal variation in the measured quantity expected by a person skilled in the art when performing the measurement and exercising a degree of care commensurate with the purpose of the measurement and the accuracy of the measuring equipment, and any quantity higher than this. In some embodiments, the term "at least about" includes the listed number minus 10% and any quantity higher, such that "at least about 10" will include 9 and any quantity greater than 9. This term may also be expressed as "about 10 or more". Similarly, the term "less than about" generally includes the listed number plus 10% and any quantity lower, such that "less than about 10" will include 11 and any quantity less than 11. This term may also be expressed as "about 10 or less".

[0021] Unless otherwise stated, all parts and percentages are by weight. Unless otherwise stated, weight percentages (wt.%) are based on the whole composition excluding any volatiles (i.e., based on dry solids content). Servo-controlled lifting devices will be discussed in the context of lifting mechanisms for supports (e.g., suction cups, electrostatic chucks, bases, etc.). However, those skilled in the art will recognize that servo-controlled lifting devices can be used in systems containing any processing chamber (e.g., a semiconductor processing chamber) that includes lifting mechanisms for transferring substrates from the chamber to and / or from the robotic arm to the chamber.

[0022] Traditional lifting mechanisms use pneumatic valves with manual restrictors to control the speed of the cylinder (also referred to herein as the pneumatic actuator). Cylinder position is monitored solely by digital end-position sensors, and the compressed air supply to the cylinder is switched via a solenoid-driven spool valve. In the context of electrostatic chuck assemblies, the energy release from the substrate is not always consistent, and if the pneumatic actuator force output of the lifting rod exceeds the substrate strength, this can lead to substrate breakage. In some cases, the substrate may shift, potentially causing it to collide with the robotic arm, resulting in substrate breakage and / or damage to the robotic arm. There is no tracking or feedback of the lifting rod position in these lifting mechanisms, making it unclear what caused the failure. Traditional lifting mechanisms also limit throughput because the pneumatic actuator must move the lifting rod slowly enough for safe substrate contact, but this movement can take 2–8 seconds.

[0023] The lifting device according to the embodiments described herein includes a position sensor that monitors the position of the cylinder throughout its stroke. The lifting device also includes a proportional pressure control valve with pressure feedback from both sides of the cylinder. This can be achieved using a single 5 / 2 spool proportional valve or through two separate pressure-controlled proportional valves. Each side of the cylinder includes a pressure sensor. The proportional pressure control valve allows for control of varying flow and pressure on each side of the cylinder. The lifting device also includes a first position sensor that sends a signal to the controller regarding the cylinder position. Once these sensors are available, the controller can control the force output by adjusting the incremental pressure between the sides, control the position by monitoring the position feedback, and control the stiffness by adjusting the average pressure between the sides. The overall system stiffness is driven by the gas mass behind each side of the cylinder.

[0024] This control allows the cylinder to move throughout its entire stroke and stop at an intermediate position, controls the movement time, and senses the substrate adhered to the support (e.g., a suction cup assembly). Furthermore, the lifting device according to the embodiments described herein enables faster lifting rod movements, which can increase system throughput. The lifting device can also control the force output, preventing substrate breakage if the support (e.g., an electrostatic chuck) fails to release. Because the lifting motion can be shortened (e.g., a total lifting stroke of 38 mm, but only 10 mm of movement is needed to transfer the substrate to the blade), the lifting device also enables faster transfer of the substrate to the robotic blade. The position control of the lifting rod can also be achieved, allowing a new substrate edge cleaning step to remove polymer deposits that occur during the etching step. For example, the substrate can be lifted only 1 mm from the support surface before cleaning.

[0025] Reference Figure 1 During operation of the process chamber 100, a robotic arm (not shown) moves a substrate 101 into the chamber 100 via a slit valve 106. The robotic arm places the substrate on the tip of a lifting rod 142, which is raised above the top of a support 110 (e.g., an electrostatic chuck) by a pneumatic lifting mechanism 146. Then, under the control of a computer control system 162, the pneumatic lifting mechanism 146 lowers the lifting rod 142, thereby positioning the substrate onto the surface of the support. The pneumatic lifting mechanism 146 may include at least one lifting rod assembly containing at least one pneumatic actuator and a servo control system in fluid communication with the at least one pneumatic actuator. The servo control system includes at least one proportional pneumatic valve, a plurality of pressure sensors, and at least one position sensor.

[0026] According to embodiments, a servo-controlled lifting device system according to embodiments herein may include a support (e.g., a suction cup assembly) and a lifting device for transferring a substrate between the support and a transfer chamber. The lifting device may include a lifting rod assembly, which includes at least one pneumatic actuator, at least one proportional pneumatic valve, a plurality of pressure sensors, at least one position sensor, and a servo control system in communication with the lifting rod assembly.

[0027] Once the lifting rod lowers the substrate 101 onto the support 110, the process can begin. This process can be etching, deposition, cleaning, etc. The process may include plasma initiation. According to some embodiments, when the support is an electrostatic chuck, the computer control system 162 can apply a DC adsorption voltage to the chuck 110 and can apply a heat transfer gas to the substrate-to-chuck interface. The adsorption voltage causes negative and positive charges to accumulate on the facing surfaces of the substrate 101 and the adsorption electrode 113, respectively.

[0028] The suction cup 110 may include an overlying dielectric (e.g., an electrostatic disk) that can support the substrate 101. After the substrate 101 is placed onto the overlying dielectric of the support 110, the lifting rod 142 continues to descend into the base 114. When the support 110 is an electrostatic suction cup, the opposite polarities of the charges on the substrate 101 and the adsorption electrode 113 generate an electrostatic attraction that presses the substrate 101 against the upper surface of the suction cup 110. The adsorption voltage is set to a sufficiently high value to generate an electrostatic force between the substrate 101 and the suction cup 110, which is sufficient to prevent the substrate from moving during subsequent process steps within the process chamber 100. The substrate 101 thus firmly held on the suction cup 110 is referred to as being "adsorbed".

[0029] After the substrate is placed on the support 110 (e.g., adsorbed), one or more process steps, such as depositing or etching a film on the substrate 101, are performed in the chamber 100. For plasma-based processes, the RF power supply 130 selectively applies RF power to the antenna 112 and between the cathode base 114 and the ground anode 104, generating plasma 103 in the region above the substrate 101. Plasma 103 provides a conductive path between the substrate and ground. However, due to the difference in mobility between electrons and positive ions, a DC voltage drop occurs across plasma 103, causing the substrate 101 to be negatively biased relative to ground. If the adsorption voltage applied to the adsorption electrode (base) 114 through the DC voltage source 120 is positive, the total DC voltage between the substrate 101 and the adsorption electrode 114 will be the sum of the substrate bias and the adsorption voltage, thus increasing the substrate bias and maintaining the electrostatic force of the substrate 101.

[0030] The lifting assembly may include three lifting rods 142 mounted on a carriage 140, which are raised and lowered by a pneumatic lifting mechanism 146. After the process steps are completed, the pneumatic lifting mechanism 146 raises the lifting rods 142 to elevate the substrate 101 above the support 110, so that the substrate 101 can be removed from the chamber 100 via a robotic arm (not shown).

[0031] In embodiments where the support 110 is an electrostatic chuck, the substrate 101 should be electro-desorbed before the lifting rod 142 can raise it; in other words, the electrostatic force holding the substrate 101 on the chuck should be removed or eliminated. The adsorption voltage source is turned off, and both the adsorption electrode 114 and the substrate 101 are grounded to remove the corresponding charge accumulated on the adsorption electrode 114 and the substrate 101 during the previous application of the adsorption voltage to the adsorption electrode 114. The substrate can be grounded by keeping the RF power supply 130 on at a reduced power level to maintain the plasma 103, which provides a conductive path from the substrate 101 to the grounded wall of the chamber 100. However, as discussed above, after using the desorption method, residual charge often remains on the substrate 101 and the chuck 110 due to charge migration and / or field emission charging. Accordingly, standard desorption methods may cause undue physical force to remove the substrate from the chuck. In some cases, using conventional desorption methods and conventional lifting rod assemblies, the substrate may break and / or crack, or be only partially removed. In the latter case, when the robotic arm moves in to retrieve the partially removed substrate, the arm may collide with the substrate, causing damage not only to the substrate but also to the robotic arm, resulting in equipment downtime. It should be noted that in embodiments where the support 110 is not an electrostatic chuck, adhesion problems may still occur. For example, material deposited on the support from a sputtering process may cause the substrate to adhere to the support. The lifting device and control system described herein can safely remove the substrate from any support without causing breakage or cracking.

[0032] The servo-controlled lifting device system described herein provides the ability to sense and control the force, position, and stiffness of pneumatic control valves. The system also enables faster lifting rod movements, which increases system throughput and control force output, thus preventing substrate breakage when the substrate adheres to a support or, for example, cannot be released by an electrostatic chuck. The system allows for faster transfer of substrates to the robotic blades (due to shortened lifting motion) and enables control of the lifting rod position, facilitating a new substrate edge cleaning step to remove polymer deposits that occur during the etching process.

[0033] exist Figure 2The diagram illustrates a lifting rod assembly 200 (for each lifting rod) according to one embodiment of this disclosure. The lifting rod assembly 200 includes a low-friction cylinder 202 having a glass bore and a graphite seal. A sleeve 204 is positioned over the shaft of the cylinder 202 and serves as a low-position hard stop for the lifting rod 214. A ball joint 206 is also attached to the shaft of the cylinder 202, allowing the lifting rod assembly 200 to align with other lifting rod assemblies while holding the substrate. The lifting rod assembly 200 may further include a linear slide 208 along which a sliding bracket 210 moves vertically. The linear slide 208 is attached to a lifting assembly support 212. The lifting rod 214 extends into the process chamber via a bellows 216, which allows vertical movement of the lifting rod 214 while maintaining a vacuum within the chamber.

[0034] As discussed above, substrate transfer is achieved mechanically using a robotic arm, the end of which is a substrate holding component, such as an end effector or a robotic blade. One type of holding component is a flat blade, which forms a vacuum channel that terminates at an outlet. The blade picks up the substrate by bringing its upper surface into contact with the bottom surface of the substrate and optionally applying a vacuum to cause the substrate to adhere to the blade. The advantage of flat blades is that they are flat and thin, and can be easily manipulated within the narrow spaces of a substrate storage container to pick up the substrate.

[0035] Another type of substrate holding component has a shoe attached to a robotic arm. The shoe can be a tray-like extension at the leading end of the arm, with a beveled profile shaped to accommodate the substrate. The shoe helps to engage the substrate and hold it in place on the arm while the robotic arm swings to transport the substrate to another location.

[0036] Figure 3 An embodiment of a lifting rod assembly 300 according to an embodiment of the present disclosure is shown. At least one lifting rod assembly 300 may be part of a lifting device for conveying a substrate between a support and a conveying plane (e.g., into a conveying chamber). The lifting rod assembly 300 may include a four (4)-way proportional pneumatic valve 301 supplied by a main source 302 of pressurized fluid (e.g., air). The proportional pneumatic valve 301 may include a pair of springs 303, 304 that enable an actuator to move between each of four (4) flow paths 305, 306, 307, 308. Flow paths 305 and 308 allow pressurized gas to flow from source 302 and to lines 309 and 310, respectively. Flow paths 306 and 307 allow gas to exit through lines 311 and 312, respectively.

[0037] The lifting rod assembly 300 also includes pressure sensors 313 and 314, which measure the air pressure in chambers 315 and 316 of the pneumatic actuator 317, respectively. Each pressure sensor may be a diaphragm-type sensor with a strain gauge (e.g., a resistance wire strain gauge and / or a piezoresistive strain gauge). According to embodiments, the proportional pressure control valve may be a single 5 / 2 spool proportional valve or two separate pressure control proportional valves. In at least one embodiment, the pressure sensor is a proportional pressure regulator with piezoelectric technology. Chambers 315 and 316 are defined on each side of the moving member (e.g., a piston) 318 and are defined by the interior of the cylinder housing 319 of the pneumatic actuator 317. A proportional pneumatic valve 301 allows pressurized gas to flow into and / or out of chambers 315 and 316. The lifting rod assembly 300 may also include a position sensor 320 that determines the position of the moving member 318 within the pneumatic actuator 317. The position sensor can be a linear position sensor and / or an inductive position sensor, such as a magnetic inductive position sensor. The moving member 318 controls the position of the lifting rod 321.

[0038] During operation, the lifting rod 321 has a load 322, which may be a combination of the weight of the substrate (not shown), the elasticity from the bellows, and / or the internal pressure of the process chamber. According to an embodiment, the lifting rod assembly 300 may also include one or more ball joints (not shown) to aid in alignment with other lifting rod assemblies in the lifting device.

[0039] exist Figure 4 Another embodiment of a lifting rod assembly 400 according to this disclosure is shown. At least one lifting rod assembly 400 may be part of a lifting device for conveying a substrate between a support and a conveying plane associated with a conveying chamber. The lifting rod assembly 400 may include two 2-way proportional pneumatic valves 401A, 401B, which are supplied by one (shown) or more main sources 402 of pressurized fluid (e.g., air). Each pneumatic valve 401 includes springs 403, 404 that enable an actuator to move between each of flow paths 405, 406, 407, 408. Flow paths 405 and 408 allow pressurized gas to flow from source 402 and into lines 409 and 410, respectively. Flow paths 406 and 407 allow gas to exit through lines 411 and 412, respectively.

[0040] The lifting rod assembly 400 also includes pressure sensors 413 and 414, which measure the air pressure in chambers 415 and 416 of the pneumatic actuator 417, respectively. Chambers 415 and 416 are defined on each side of a moving member (e.g., a piston) 418 and are defined internally by the cylinder housing 419 of the pneumatic actuator 417. Proportional pneumatic valves 401A and 401B allow pressurized gas to flow into and / or out of chambers 415 and 416. The lifting rod assembly 400 may also include a position sensor 420, which determines the position of the moving member 418 within the pneumatic actuator 417. The moving member 418 controls the position of the lifting rod 421. During operation, the lifting rod 421 has a load 422, which may be a combination of the weight of a substrate (not shown), the spring force from a bellows, and / or the internal pressure of the process chamber. According to one embodiment, the lifting rod assembly 400 may also include one or more ball joints (not shown) to aid in alignment with other lifting rod assemblies in the lifting device.

[0041] The aforementioned lifting assemblies 300 and 400 may be part of a servo control system. The servo control system actuates pneumatic valves 301, 401A, and 401B to direct pressurized gas into and / or discharge pressurized gas from chambers 315, 316, 415, and 416. The servo control system utilizes measurements from pressure sensors 313, 314, 413, and 414 and position sensors 320, 420 to determine the output force of pneumatic actuators 317 and 417 and the stiffness of valves 301, 401A, and 401B. In addition to the lifting rod assemblies 300 and 400, a controller (not shown) completes the servo control system. The servo control system is configured to maintain a closed loop, wherein at least one of the chamber pressure and the position of the moving member is controlled within the pneumatic actuator. At least one proportional pneumatic valve 301, 401A, 401B is configured to guide pressurized fluid 302, 402 through at least one of a plurality of fluid flow paths 305, 306, 307, 308 in response to a control signal from a servo control system. The controller calculates an appropriate pressure for each cylinder chamber to move the lifting component as quickly as possible while avoiding damage to the base plate.

[0042] Figure 5 A servo control system 500 according to an embodiment of this document is shown. A path planner 502 generates a trajectory (y... cmd The position controller 504 generates a command force (f) required to move the lifting rod assembly 514 closer to the base plate, based on the generated trajectory and feedback (y) received from the position sensor. cmd The function of force estimator 506 is to determine whether contact occurs between the support and the substrate, and whether the support is engaged or disengaged. Based on the estimated force (f) of force estimator 506... eThe force controller 508 commands the path planner 502 to either continue moving or pause until the support (e.g., an electrostatic chuck) is completely disengaged, while maintaining a small force to push the substrate without breaking it. The force controller 508 receives two inputs: a command force (f) from the position controller 504. cmd ) and the estimated force (f) from the force estimator 506 e The force controller 508 calculates the appropriate force (f). d This is to keep the contact force between the lifting rod and the substrate below a certain limit (i.e., to prevent the substrate from cracking), and to maintain the position of the lifting rod close to the substrate. The pressure controller 510 receives the required force (f) from the force controller 508. d The command pressure is calculated for each chamber of the pneumatic actuator 512. The pressure controller 510 actually generates an appropriate force to move the lifting rod while preventing the substrate from cracking. The pneumatic actuator 512 generates a desired force output (f) based on the amount of chamber pressure p1 and p2 to move at least one lifting rod or maintain contact with the substrate. It should be noted that each of the position controller 504, force estimator 506, force controller 508, and pressure controller 510 may be a module of the controller of a servo control system, or each may be a separate controller.

[0043] In one embodiment, servo control of the lifting device can be implemented via a control algorithm for controlling the lifting device. For example, the pneumatic actuators 317 and 417 of the lifting device may include cylinders. See also Figure 3 and 4 The pressure P in chambers 315, 316, 415, and 416 a P b The difference between them determines the output force F, and their sum determines the desired stiffness of cylinders 318 and 418. Therefore, in order to control the force and stiffness of pneumatic actuators 317 and 417, it is necessary to be able to control the pressure P in cylinder chambers 315, 316, 415, and 416 individually. a V a A a and P b V b A b .

[0044] The pressure P in each chamber a V a A a and P b V b A b air mass flow rate The relationship between the piston position ±x. Each chamber 315, 316, 415, 416 can be modeled as a control volume using the following assumptions: 1) the air is an ideal gas; 2) the pressure and temperature are uniformly distributed in each chamber; and 3) the kinetic and potential energy of the air are negligible. Considering these assumptions, and applying the conservation of mass, the ideal gas model, and the conservation of energy to each chamber, we obtain equation (1):

[0045]

[0046] Where R is the ideal gas constant, P is the pressure, T is the absolute temperature, and V is the volume, and This refers to the mass flow rate into or out of cylinder chambers 315, 316, 415, and 416. The volume of each chamber depends on the piston position, as shown in equation (2):

[0047]

[0048] Where V0 is the inactive volume at the end of the stroke, and includes the volume V of the tube connecting chambers 315, 316, 415, 416 to the pressure sensor. a V b A is the effective piston area, L is the piston stroke, and x p This refers to the piston position. The stationary volume V in each chamber 315, 316, 415, 416 of cylinders 318 and 418. a V b The associated normalized stationary length can be defined as L oa =V oa / A a , and L ob =V ob / A b , among which Figure 3 and Figure 4 In the diagram, a and b represent the two chambers 315, 316, 415, and 416 of the cylinder. Therefore, the volume of each chamber, varying with piston position, will be as shown in equation (3):

[0049]

[0050] In formulas (2) and (3), the positive and negative signs correspond to chambers a and b, respectively. Combining equations (1) and (3), the pressure equation for the chambers becomes...

[0051]

[0052] An isothermal approximation can be used for the chamber charging / discharging process, and good results can be obtained. However, to compensate for the isothermal process assumption, the controller should be designed to be robust to parameter uncertainties. The force generated by the cylinder is shown in equation (5):

[0053] F = P a A a -P b A b -P atm A r (5)

[0054] Where A r It is the cross-sectional area of ​​the cylinder rod, and P atm It is atmospheric pressure. The cylinder stiffness is the rate of change of the cylinder force F relative to the piston position x, where m is the mass of the air inside the chamber. a,b As shown below in equation (6), it is considered constant:

[0055]

[0056] Using the force from (5) into (6), we obtain equation (7):

[0057]

[0058] Assuming a constant temperature, the pressure in each chamber will vary with the air mass (m) inside the chamber and the piston position (x). p The time derivative of pressure changes accordingly. This becomes equation (8):

[0059]

[0060] Comparing (4) and (8), the partial derivative of pressure with respect to position is:

[0061]

[0062] From (7) and (9), the actuator stiffness can be written as

[0063]

[0064] The lifting rod assemblies 300 and 400 described above can be used as part of a servo control system in a process chamber to remove (e.g., desorb) at least one substrate from a support (e.g., an electrostatic chuck assembly).

[0065] According to the servo-controlled lifting device of the embodiments herein, the position of at least one lifting rod 321, 421 can be determined after receiving signals from position sensors 320, 420 indicating the position (x) of indicator cylinders 318, 418. The position of at least one lifting rod 321, 421 also indicates the position of the substrate received by at least one lifting rod 321, 421. For example, the position of at least one lifting rod 321, 421 combined with a predetermined thickness of the substrate enables precise determination of the substrate's position within the process chamber.

[0066] The servo-controlled lifting device according to the embodiments described herein enables the determination of the force F generated by the cylinder. See equation (5). According to the embodiments, if the servo control system determines that the positive force F (e.g., when the lifting rod rises) reaches a predetermined value, for example indicating a relatively high output force of the substrate adhering to the support, the system can reduce (e.g., at a linear rate, exponential rate) the pressure P in chambers 315, 415. a and / or increase the pressure P in chambers 316 and 416 b This slows down or reverses the movement of the lifting rod. In practice, the substrate attached to the support can be peeled off. Servo control of the lifting device, as described herein, can gradually increase or decrease the output force to prevent substrate breakage and / or slowly peel the substrate off the support assembly.

[0067] This document also discloses a method for controlling lifting devices associated with process chambers, as described above. Figure 6 A process 600 is described, relating to a substrate transfer between a process chamber and a transfer plane associated with a transfer chamber. After substrate processing is completed at block 602, at block 604, the substrate is released from the semiconductor process chamber (e.g., from a support). At block 606, a lifting lever is actuated to remove the substrate from the support. As described above, a servo control system controls the lifting device and can determine the substrate position and the force output of the cylinder. According to an embodiment, the servo control system can control the speed of the lifting lever and can control how high and / or how low the lifting lever is raised. The servo control system can also control the force output of the cylinder by independently controlling the pressure in each chamber of the pneumatic control valve to avoid applying excessive force that could cause the substrate to break. At block 608, a robotic arm is activated to grasp the substrate from the lifting lever assembly. As described above, the robotic arm can move just high enough to clear the lifting lever assembly. At block 610, the robotic arm removes the substrate from the process chamber system. Once the substrate is received, the robotic arm can transfer the substrate into the transfer chamber. At box 612, if the system receives a signal to process another substrate through the semiconductor chamber, then at box 614, the robotic arm positions the new substrate for processing on the lifting rod. At box 616, the lifting rod is lowered together with the substrate to place the substrate on the support.

[0068] Reference Figure 7 According to an embodiment, method 700 may include, at block 702, a controller receiving a first pressure measurement from a first pressure sensor, the first pressure sensor measuring the pressure in a first chamber of the pneumatic actuator. The controller may be a computing device such as a programmable logic controller, a system-on-a-chip (SoC), etc. The method may further include, at block 704, a controller receiving a second pressure measurement from a second pressure sensor, the second pressure sensor measuring the pressure in a second chamber of the pneumatic actuator. At block 706, the method may include, by the controller, receiving a position measurement from a position sensor, the position sensor measuring the position of a moving member (e.g., a cylinder) of the pneumatic actuator. At block 708, the method may include generating a control signal based on the first pressure measurement, the second pressure measurement, the position measurement, and the maximum acceptable contact force between the substrate and the lifting mechanism. At block 710, the method may include transmitting the control signal to at least one proportional pneumatic valve of a servo control system to control pressurized fluid to the pneumatic actuator. At block 712, the method may include operating the servo control system to extend at least one lifting rod and lift the substrate from the support via the at least one lifting rod. According to an embodiment, the method may further include using a robotic arm to transfer a substrate from at least one lifting rod to a transfer plane and into a transfer chamber.

[0069] According to one embodiment, the controller can determine the difference between a first pressure measurement and a second pressure measurement to determine the output force of the pneumatic proportional valve. In one embodiment, the controller adds the first pressure measurement to the second pressure measurement to determine the stiffness of the pneumatic proportional valve. The stiffness can be set to a high value to make the control system more robust to static resistance in the lifting mechanism. In response to the output force, stiffness, and position of the moving member, the controller can control at least one pneumatic actuator to move the lifting mechanism upward while preventing the base plate from breaking.

[0070] Figure 8The illustration depicts a method 800 of operating a servo control system to lift a substrate from a substrate support. According to the embodiments described herein, the servo control system is configured to control a lifting rod assembly for lifting the substrate. Method 800 may include, at block 802, actuating at least one proportional pneumatic valve to allow gas flow through a first gas line into (or out of) a first chamber of a pneumatic actuator of the lifting rod assembly, and through a second gas line into (or out of) a second chamber of the pneumatic actuator. As discussed herein, in embodiments, the lifting rod assembly may include, for example, two proportional pneumatic valves. A first valve may control the pressure in the first gas line, a second valve may control the pressure in the second gas line, and both valves may be controlled by the servo control system. At least one proportional pneumatic valve may also include a vent to release pressure in the gas supply line, if necessary, to balance the pressure between the first and second chambers and achieve a desired force output or contact force of at least one lifting rod on the substrate.

[0071] Method 800 may further include, at block 804, measuring the pressure in a first gas line using a first pressure sensor and measuring the pressure in a second gas line using a second pressure sensor. Each pressure sensor may be located at any point on the line between at least one proportional pneumatic valve and the pneumatic actuator. In an embodiment, each pressure sensor may be positioned and operable to measure the pressure at the inlet of each chamber of the pneumatic actuator.

[0072] Method 800 may further include measuring the position of a moving component of the pneumatic actuator (e.g., a piston connected to a lifting rod) at block 806 using a position sensor. Figure 3 and Figure 4 As shown, when the moving member is approximately at the center of the pneumatic actuator, the position is x = 0. If the moving member moves away from the substrate (e.g., downwards), the moving member moves in the negative direction (-x). If the moving member moves towards the substrate (e.g., upwards), the moving member moves in the positive direction (+x).

[0073] Method 800 may further include block 808, which utilizes a servo control system to control at least one pneumatic actuator to apply a contact force of approximately 2N to approximately 10N to the substrate via a moving member. When the moving member, including a lifting rod, contacts the substrate to lift it from the support, the force applied to the substrate by the moving member is controlled to be approximately 2N to approximately 10N to prevent the substrate from cracking or breaking. The servo control system actuates at least one proportional pneumatic valve to increase, decrease, or maintain the pressure supplied to each chamber (or within each chamber) of the pneumatic actuator. According to an embodiment, the pressure supplied to each chamber can be independently controlled by a plurality of proportional pneumatic valves. For example, the pressure p in the first chamber... AIt can be increased, while the pressure p in the second chamber B This can be reduced (e.g., by discharge). If the servo control system determines that moving the moving component will cause a contact force on the substrate exceeding about 2N to about 10N, such as about 2N, about 3N, about 4N, about 5N, about 6N, about 7N, about 8N, about 9N, or about 10N, the servo control system will determine that the wafer is being adhered and will actuate at least one proportional pneumatic valve to maintain the pressure in each chamber. This applies a constant force to the substrate, which will, for example, peel the substrate from the support, but will not cause the substrate to break or crack.

[0074] Method 800 further includes lifting the substrate from the support at block 810 by means of a moving member. As discussed above, the moving member will move and apply a contact force of about 2N to about 10N to the substrate. The moving member may move in the negative direction, stop moving, or move in the positive direction to maintain the contact force on the substrate. Once the moving member has moved from its central position (x=0) in the positive (+x) direction to a position of about 1mm to about 7mm, the servo control system may accelerate the movement of the moving member (which has a wafer on it). For example, when the position of the moving member is about 1mm to about 7mm, or about 2mm from the center of the moving member in the positive direction, the servo control system sends a signal to a proportional pneumatic valve to increase the pressure in at least one of the first or second chambers to accelerate the moving member in the positive direction. According to embodiments, the method may include accelerating the moving member to about 10 mm / s to about 150 mm / s, or about 15 mm / s to about 125 mm / s, or about 20 mm / s to about 100 mm / s, or about 25 mm / s to about 75 mm / s, or about 30 mm / s to about 50 mm / s, or about 30 mm / s to about 35 mm / s, or about 30 mm / s, or about 35 mm / s, or about 100 mm / s. It should be noted that, although... Figure 3 and Figure 4 The accompanying diagram is shown in a horizontal arrangement, but the lifting rod assembly is typically in a vertical orientation.

[0075] According to various embodiments, during substrate processing in the chamber, at least one lifting rod is lowered to a hard stop position (y = 0). After processing, at least one lifting rod moves upward at a speed of approximately 1 mm / s to approximately 3 mm / s, or approximately 2 mm / s, to contact the substrate at the substrate release plane (e.g., y = 20 mm). As described above, the contact force of at least one lifting rod on the substrate is controlled to approximately 2 N to approximately 10 N. Once the moving member in the pneumatic actuator and at least one lifting rod (with the substrate on the lifting rod) have moved approximately 2 mm to approximately 7 mm in the positive direction from the intermediate position in the pneumatic actuator, the servo control system determines that the substrate has left the support.

[0076] The servo control system can then accelerate the moving component to speeds of approximately 10 mm / s to approximately 150 mm / s, or approximately 15 mm / s to approximately 125 mm / s, or approximately 20 mm / s to approximately 100 mm / s, or approximately 25 mm / s to approximately 75 mm / s, or approximately 30 mm / s to approximately 50 mm / s, or approximately 30 mm / s to approximately 35 mm / s, or approximately 30 mm / s, or approximately 35 mm / s, or approximately 100 mm / s. When the substrate is at or near the substrate exchange plane (e.g., y = 25 mm), the servo control system can slow the speed of at least one lifting rod and the substrate to approximately 1 mm / s to approximately 25 mm / s, or approximately 5 mm / s to approximately 20 mm / s, or approximately 10 mm / s to approximately 15 mm / s, so that the end effector of the robotic arm makes gentle contact with the substrate located at the wafer exchange plane (e.g., y = 25 mm). Once the substrate is securely positioned on the terminal actuator, the robotic arm (carrying the substrate received on the robotic arm) can move at a speed of approximately 35 mm / s to approximately 50 mm / s to the substrate lifting plane (e.g., y = 30 mm) and transfer the substrate to the transfer chamber. In this embodiment, an upper hard stop is provided approximately 15 mm to approximately 50 mm, or approximately 35 mm above the lowered hard stop.

[0077] According to the implementation, the above method can be reversed. Specifically, the robotic arm and the terminal actuator (with a new substrate received on the terminal actuator) can move from the wafer lifting plane to the substrate exchange plane at a rate of about 35 mm / s to about 50 mm / s. At the wafer exchange plane, the substrate is received by at least one lifting rod, which then descends at a rate of about 1 mm / s to about 25 mm / s, or about 5 mm / s to about 20 mm / s, or about 10 mm / s to about 15 mm / s. Once the substrate and at least one lifting rod leave the terminal actuator, the at least one lifting rod is lowered at a speed of about 10 mm / s to about 150 mm / s, or about 15 mm / s to about 125 mm / s, or about 20 mm / s to about 100 mm / s, or about 25 mm / s to about 75 mm / s, or about 30 mm / s to about 50 mm / s, or about 30 mm / s to about 35 mm / s, or about 30 mm / s, or about 35 mm / s, or about 100 mm / s. When the substrate reaches the support, the speed is reduced to about 1 mm / s to about 3 mm / s, or about 2 mm / s, to gently place the substrate on the support.

[0078] When the substrate is raised and lowered, the above-described device, system, and method shorten the range of motion of at least one lifting rod.

[0079] The foregoing description sets forth numerous specific details, such as examples of specific systems, components, methods, etc., to provide a good understanding of several embodiments of this disclosure. However, it will be apparent to those skilled in the art that at least some embodiments of this disclosure can be practiced without these specific details. In other instances, well-known components or methods have not been described in detail, or have been presented in a simple block diagram format to avoid unnecessarily obscuring the disclosure. Therefore, the specific details set forth are merely exemplary. Specific embodiments may differ from these exemplary details and may still be contemplated within the scope of this disclosure.

[0080] Although the operations of the methods herein are shown and described in a specific order, the order of operations for each method can be changed, so that some operations can be performed in reverse order, or so that some operations can be performed at least partially concurrently with other operations. In another embodiment, instructions or sub-operations of different operations can be performed intermittently and / or alternately.

[0081] It should be understood that the foregoing description is illustrative and not restrictive. Many other embodiments will become apparent to those skilled in the art upon reading and understanding the foregoing description. Therefore, the scope of the disclosure should be determined by referring to the appended claims, together with the full scope of the equivalents claimed by such claims.

Claims

1. A lifting device for conveying a substrate between a support member and a conveying plane, the lifting device comprising: The lifting mast assembly includes: A lifting rod, configured to move the base plate between the support and the transfer plane; At least one pneumatic actuator, the pneumatic actuator comprising a moving member configured to provide a load to the lifting rod; At least one proportional pneumatic valve, the at least one proportional pneumatic valve being configured to control the fluid flow rate between the at least one pneumatic actuator and a pressurized fluid source or vent. A plurality of pressure sensors, each configured to independently measure the pressure in a corresponding supply line of the at least one pneumatic actuator; and At least one position sensor, the at least one position sensor being configured to measure the position of the moving member; and A servo control system, which communicates with the lifting mast assembly, includes a controller configured to: The output force is determined based on the command force and the estimated force, wherein the command force is based at least in part on the position measurement results of the at least one position sensor, and wherein the estimated force is based at least in part on the pressure measurement results of the plurality of pressure sensors and the position measurement results; A control signal is generated based on the output force; and The control signal is applied to the at least one proportional pneumatic valve to move the movement. member.

2. The lifting device as claimed in claim 1, wherein the lifting device comprises a plurality of lifting rod assemblies.

3. The lifting device of claim 2, wherein the plurality of lifting rod assemblies are configured to move the base plate between the support and the conveying plane.

4. The lifting device as claimed in claim 2, wherein the servo control system communicates with the plurality of lifting rod assemblies.

5. The lifting device of claim 4, wherein the servo control system is configured to maintain a closed loop, wherein at least one of the chamber pressure or the position of the moving member is controlled within the at least one pneumatic actuator.

6. The lifting device of claim 4, wherein the at least one pneumatic actuator comprises a plurality of chambers, and wherein the at least one proportional pneumatic valve is configured to direct pressurized fluid into at least one of the plurality of chambers in response to a control signal from the servo control system.

7. The lifting device of claim 1, wherein the at least one pneumatic actuator comprises a plurality of chambers, each chamber being connected to a corresponding supply line, the corresponding supply line being measured by a corresponding pressure sensor among the plurality of pressure sensors.

8. The lifting device of claim 1, wherein the lifting device comprises a plurality of proportional pneumatic valves configured to transfer fluid between the at least one pneumatic actuator and the pressurized fluid source or the vent.

9. The lifting device of claim 1, wherein the servo control system comprises a controller attached to the at least one pneumatic actuator, the plurality of pressure sensors, the at least one position sensor, and the at least one proportional pneumatic valve.

10. A method comprising the steps of: The controller receives a first pressure measurement result from a first pressure sensor, which measures the pressure in the first chamber of the pneumatic actuator. The controller receives a second pressure measurement result from a second pressure sensor, which measures the pressure in the second chamber of the pneumatic actuator. The controller receives position measurement results from a position sensor, which measures the position of the moving component of the pneumatic actuator; The controller determines the output force based on a command force and an estimated force, wherein the command force is at least partially based on the position measurement result, and wherein the estimated force is based on the first pressure measurement result, the second pressure measurement result, and the position measurement result; The control signal is generated based on the output force; The control signal is transmitted to at least one proportional pneumatic valve of the servo control system to control the pressurized fluid to the pneumatic actuator; and The servo control system is operated to extend at least one lifting rod and to lift the substrate from the support via the at least one lifting rod.

11. The method of claim 10, further comprising the step of: using a robotic arm to transfer the substrate from the at least one lifting rod to the transfer chamber.

12. The method of claim 10, wherein the controller determines the difference between the first pressure measurement result and the second pressure measurement result to determine the output force of the pneumatic actuator, and wherein the controller adds the first pressure measurement result to the second pressure measurement result to determine the stiffness of the pneumatic actuator.

13. The method of claim 12, wherein in response to the output force, the stiffness, and the position of the moving member, the controller controls the at least one proportional pneumatic valve by determining the pressure in each of the two chambers of the pneumatic actuator.

14. A method comprising the following steps: Operating a servo control system to lift a substrate from a substrate support, wherein the servo control system is configured to control a lifting rod assembly for lifting the substrate, includes the following steps: Actuate at least one proportional pneumatic valve to allow gas flow through a first gas line into the first chamber of the pneumatic actuator of the lifting rod assembly, and through a second gas line into the second chamber of the pneumatic actuator; The pressure in the first gas line is measured using a first pressure sensor, and the pressure in the second gas line is measured using a second pressure sensor. The position of the moving component of the pneumatic actuator is measured using a position sensor; The output force is determined based on the command force and the estimated force, wherein the command force is based at least in part on the position of the moving member, and wherein the estimated force is based on the pressure in the first gas line, the pressure in the second gas line, and the position of the moving member; Based on the output force, the servo control system controls at least one proportional pneumatic valve to apply a contact force of about 2N to about 10N to the substrate through the moving member. and The base plate is lifted from the support by a lifting rod, which is operable to receive loads through the moving member.

15. The method of claim 14, wherein the lifting rod assembly comprises: The lifting rod; The pneumatic actuator includes the moving member. The at least one proportional pneumatic valve; The first pressure sensor; The second pressure sensor, and The position sensor.

16. The method of claim 14, wherein the controller of the servo control system is connected to the pneumatic actuator, the at least one proportional pneumatic valve, the first pressure sensor, the second pressure sensor, and the position sensor.

17. The method of claim 14, wherein the step of controlling the at least one proportional pneumatic valve comprises the steps of: maintaining, reducing, or reversing the gas flow to at least one of the first chamber or the second chamber.

18. The method of claim 14, wherein the step of controlling the at least one proportional pneumatic valve comprises the step of maintaining the pressure on the first chamber and the second chamber at a constant value to apply a constant contact force to the substrate through the moving member.

19. The method of claim 14, wherein when the position of the moving member is about 1 mm to about 7 mm, or about 2 mm from the center of the moving member in the positive direction, the servo control system sends a signal to the proportional pneumatic valve to increase the pressure in at least one of the first chamber or the second chamber to accelerate the moving member in the positive direction.

20. The method of claim 19, wherein the moving member is accelerated to a speed of about 50 mm / s to about 150 mm / s, or about 75 mm / s to about 125 mm / s, or about 100 mm / s.

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