Methods, systems, and apparatus, among other things, for chucking operations using adjusted chucking voltage when process shifts occur

Abstract

Methods, systems, and apparatuses are disclosed for chucking operations using an adjusted chucking voltage when a process shift occurs. In one embodiment, a method includes performing a first process operation on a substrate in a process chamber. The first process operation includes applying a chucking voltage to an electrostatic chuck (ESC) in the process chamber while the substrate is supported on the ESC. The method includes determining that a process shift has occurred. Determining that the process shift has occurred includes one or more of determining that a center of the substrate has moved a post-process shift relative to a center pre-process position prior to the first process operation or determining that a defect count of a backside surface of the substrate exceeds a defect threshold. The method includes determining an adjusted chucking voltage based on the occurrence of the process shift.

Description

[0001] background

[0002] field

[0003] Embodiments of this disclosure relate to semiconductor processing, and more specifically to electrostatically clamping a substrate. Background Technology

[0004] Process drift can occur during the lifespan of an electrostatic chuck. For example, contaminant deposition and / or surface roughening on the electrostatic chuck can cause changes in the clamping force applied to the substrate. Process drift can hinder processing operations, cause substrate adhesion and / or substrate breakage, cause substrate ejection during processing, cause front and back defects on the substrate, and limit the operational life of the electrostatic chuck.

[0005] Therefore, there is a need for an improved electrostatic chuck and its usage method. Summary of the Invention

[0006] This document describes an electrostatic chuck and its usage. In one embodiment, a method of clamping a substrate includes performing a first processing operation on the substrate in a processing chamber. The first processing operation includes applying a clamping voltage to the ESC disposed in the processing chamber while the substrate is supported on the electrostatic chuck (ESC). The method includes determining that a processing displacement has occurred. Determining that a processing displacement has occurred includes one or more of the following steps: determining that the center of the substrate has been displaced by a post-processing displacement relative to a pre-processing position prior to the first processing operation, or determining that the defect count on the back surface of the substrate exceeds a defect threshold. The method includes determining an adjusted clamping voltage based on the occurrence of the processing displacement.

[0007] In one embodiment, a non-transitory computer-readable medium for performing a clamping operation includes instructions that, when executed, cause a plurality of operations to be performed. The plurality of operations include performing a first processing operation on a substrate in a processing chamber. The first processing operation includes applying a clamping voltage to the ESC in the processing chamber while the substrate is supported on an electrostatic chuck (ESC). The plurality of operations includes determining that a processing displacement has occurred. Determining that a processing displacement has occurred includes one or more of the following steps: determining that the center of the substrate has been displaced by a post-processing displacement relative to a pre-processing position prior to the first processing operation, or determining that a defect count on the back surface of the substrate exceeds a defect threshold. The plurality of operations includes determining an adjusted clamping voltage based on the occurrence of the processing displacement.

[0008] In one embodiment, a system for processing a substrate includes a processing chamber comprising a processing volume. The system includes an electrostatic chuck (ESC) disposed within the processing chamber. The system includes a controller comprising instructions that, when executed, cause the processing chamber to perform a first processing operation on the substrate within the processing chamber. The first processing operation includes applying a clamping voltage to the ESC while the substrate is supported on the ESC. When executed, the instructions cause a processor to determine that a processing shift has occurred. Determining that a processing shift has occurred includes one or more of the following steps: determining that the center of the substrate has been moved by a post-processing shift relative to a pre-processing position prior to the first processing operation, or determining that a defect count on the back surface of the substrate exceeds a defect threshold. When executed, the instructions cause the processor to determine an adjusted clamping voltage based on the occurrence of the processing shift. Attached Figure Description

[0009] To facilitate a detailed understanding of the above features of this disclosure, a more specific description of the disclosure briefly summarized above can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings only show exemplary embodiments and should not be considered as limiting the scope, as this disclosure allows for other equivalent embodiments.

[0010] Figure 1 This is a block diagram of a method for clamping a substrate according to one embodiment.

[0011] Figure 2 It is an implementation method that can be used for execution. Figure 1 A partial schematic diagram of a system for processing a substrate according to method 100 shown.

[0012] Figure 3A This is a schematic partial cross-sectional view of a processing chamber according to one embodiment.

[0013] Figure 3B According to one implementation method Figure 3A An enlarged schematic diagram of the processing chamber is shown.

[0014] Figure 3C According to one implementation method Figure 3A The diagram shows an enlarged view of the processing chamber, in which a sensor substrate device is located.

[0015] Figure 4 This is a schematic diagram of a defect count map of the back surface of a substrate after a first processing operation, according to one embodiment.

[0016] Figure 5 It is based on the support of one implementation method Figure 3AA schematic top view of the base plate on the robot blade of the robot shown.

[0017] Figure 6 It is based on the support of one implementation method Figure 3A A schematic side view of the base plate on the robot blade of the robot shown.

[0018] For ease of understanding, the same reference numerals are used as much as possible to denote the same shared elements in the figures. It is contemplated that elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0019] Various aspects of this disclosure relate to methods, systems, and apparatus for performing clamping operations using an adjusted clamping voltage when a displacement occurs.

[0020] Figure 1 This is a block diagram of a method 100 for clamping a substrate according to one embodiment. At operation 102, a first processing operation is performed on the substrate in a processing chamber. The first processing operation includes applying a clamping voltage to the ESC in the processing chamber while the substrate is supported on the ESC. The clamping voltage is a predetermined clamping voltage selected to generate a target clamping force. The first processing operation includes performing one or more of an etching operation, a deposition operation, an oxidation operation, an annealing operation, and / or an ion implantation operation while the substrate is supported on the ESC.

[0021] After operation 102, operation 104 is performed to determine whether processing displacement has occurred. Processing displacement indicates that the predetermined clamping voltage no longer produces the target clamping force due to a change in ESC conditions. An ESC that allows processing displacement may be referred to as a displaced ESC. Determining whether processing displacement has occurred includes one or more of the following steps: determining whether the center of the substrate has moved by post-processing displacement relative to the pre-processing position prior to the first processing operation, and / or determining whether contamination on the back surface of the substrate exceeds a defect threshold. Contamination on the back surface can be determined using a count of defects (such as particles) present on the back surface of the substrate. Post-processing displacement is a displacement in the XY plane (e.g., a horizontal plane) from the initial pre-processing position (e.g., the center) by a predetermined threshold. The predetermined threshold is in the range of 0.5 mm to 10 mm, such as 1 mm to 5 mm. Determining whether the center of the substrate has moved by post-processing displacement includes lifting the substrate from the ESC and moving the substrate past light emitted by one or more laser sensors after performing the first processing operation. Moving the substrate through light emitted by one or more laser sensors includes moving the substrate while it is supported on a robot blade. Determining whether the center of the substrate has been moved by post-processing displacement also includes determining multiple positions along the outer periphery of the substrate, said multiple positions being located in the XY plane, and calculating the post-processing position of the center using said multiple positions. Determining whether the center of the substrate has been moved by post-processing displacement also includes determining the post-processing displacement between the post-processing position and the pre-processing position.

[0022] In one example, the defect threshold is in the range of 5,000 to 10,000 defects, such as in the range of 8,000 to 10,000 defects. In another example, the defect threshold is greater than 10,000 defects. At operation 104, it is determined whether a processing shift has occurred in one or more of the processing chamber and / or the second chamber (such as a loading locking chamber, a transfer chamber, a buffer chamber, an interface chamber, or a plant interface chamber).

[0023] At operation 106, if processing displacement occurs, an adjusted clamping voltage is determined. In one embodiment, which can be combined with other embodiments, determining the adjusted clamping voltage includes moving the sensor substrate assembly into the processing chamber and onto the ESC, and measuring the clamping force applied to the sensor substrate assembly while it is supported on the ESC. The sensor substrate assembly includes a plurality of embedded sensors that measure the applied electrostatic force applied to the sensor substrate assembly by the ESC. The adjusted clamping voltage is selected to generate a target clamping force with the displaced ESC. In one embodiment, which can be combined with other embodiments, determining the adjusted clamping voltage includes ejecting a workpiece onto the displaced ESC moved into the first processing chamber. The workpiece includes a substrate or a second substrate.

[0024] The ejection operation involves applying an initial clamping voltage to the ESC and allowing back-side gas to flow towards the back surface of the workpiece. The initial clamping voltage is the voltage at which the back-side gas leaks past the outer edge of the workpiece at a leakage rate below a leakage threshold. The initial clamping voltage may be the same as, or lower than, the clamping voltage applied in operation 102. The ejection operation also includes ramping up or down the initial clamping voltage to a leakage voltage, at which the back-side gas leaks past the outer edge of the workpiece at a leakage rate exceeding a leakage threshold, while allowing back-side gas to flow towards the back surface. In one example, the back-side gas flows at a back pressure of approximately 16 Torr, while the processing volume of the processing chamber is maintained at approximately 10 millitors. The initial clamping voltage ramps up or down in voltage increments, such as 25 volts or 100 volts. The leakage threshold is in the range of 2.0 standard cubic centimeters (sccm) to 5.0 sccm per minute, such as 2.0 sccm. The adjusted clamping voltage is determined by adding a safety voltage margin to or subtracting it from the leakage voltage. If the leakage voltage is determined by sloping the initial clamping voltage down to the leakage voltage, the safety voltage margin is added to the leakage voltage to provide a working margin higher than the leakage voltage (for generating the target clamping voltage). If the leakage voltage is determined by sloping the initial clamping voltage up to the leakage voltage, the safety voltage margin is subtracted from the leakage voltage to provide a working margin lower than the leakage voltage (for generating the target clamping voltage). The safety voltage margin is determined by multiplying the leakage voltage by a ratio factor, and said ratio factor is 0.2 or greater. The safety voltage margin can be, for example, 200 volts or 300 volts.

[0025] At operation 108, a second processing operation is performed in the processing chamber. The second processing operation is performed on a substrate, a second substrate, or a third substrate. The second processing operation includes applying an adjusted clamping voltage to the ESC while the substrate, second substrate, or third substrate is supported on the ESC. During the second processing operation, the adjusted clamping voltage is used to clamp the substrate, second substrate, or third substrate to the ESC. The second processing operation includes one or more of etching, deposition, oxidation, annealing, and / or ion implantation operations.

[0026] Figure 2 It is an implementation method that can be used for execution. Figure 1The illustrated method 100 is a partial schematic diagram of a system 200 for processing a substrate. System 200 includes a processing chamber 201 and a second chamber 203. A controller 220 is coupled to the processing chambers 201 and 203 to control their operation. The second chamber 203 includes a volume 218 and a robot 227 having robot blades 226 and configured to extend and retract the robot blades 226 into and out of the processing volume 206 of the processing chamber 201. The second chamber 203 may be a loading locking chamber, a transfer chamber, a buffer chamber, an interface chamber, or a factory interface chamber. The second chamber 203 may be directly attached to the processing chamber 201, or it may be detached from the processing chamber 201 (e.g., indirectly attached). The robot blades 226 are used to move the substrate between chambers 201 and 203.

[0027] System 200 includes one or more sensors that monitor conditions and / or properties of one or more aspects of system 200, such as the volume 118 of the second chamber 203, the processing volume 206 of the processing chamber 201, and / or the substrate surface. System 200 includes one or more modules 290 (one module is shown) having one or more sensors 291a-291d (four modules are shown) disposed in the second chamber 203. At least one of the one or more sensors 291a-291d is a particle sensor configured to measure a defect count of defects (such as contaminants) on the back surface of the substrate. In one example, the defect count is measured in a tool or chamber not directly connected to the processing chamber 201. Sensors 291a-291d may be metrological sensors, on-substrate spectral sensors (such as X-ray fluorescence spectroscopy (XRF) sensors and / or X-ray photoelectron spectroscopy (XPS) sensors), particle counters, cameras, optical sensors, and / or position sensors.

[0028] System 200 includes one or more laser sensors 280 coupled to a second chamber 203. Each of the laser sensors 280 is part of a Local Center Detector (LCF) of the second chamber 203. The one or more laser sensors 280 may be disposed within or outside a volume 218. The laser sensors 280 are used to detect at least three locations on the outer periphery of a substrate (when carried on a robot blade 226) and determine the center of the substrate from these locations. The measured center of the substrate can be compared with a desired position based on robot motion to determine whether positional displacement has occurred on the ESC. This disclosure contemplates that one or more laser sensors 280 may be disposed in a processing chamber 201 or a third chamber 205.

[0029] System 200 includes a third chamber 205 (measuring chamber) directly or indirectly connected to the second chamber 203. The third chamber 205 includes a particle sensor 293a configured to measure a defect count of defects on the back side of the substrate after a first processing operation is performed on the substrate in the processing chamber 201. The particle sensor 293a may be a metrological sensor, a substrate-on-board spectral sensor (such as an X-ray fluorescence spectroscopy (XRF) sensor and / or an X-ray photoelectron spectroscopy (XPS) sensor), a particle counter, a camera, an optical sensor, and / or a position sensor. In one embodiment, which may be combined with other embodiments, the particle sensor 293a configured to measure defect counts is disposed in a third chamber 205, different from the processing chamber 201, and is not directly attached to the processing chamber 201. In such embodiments, the substrate is removed from the processing chamber 201 before defect count measurement, and the defect count is measured while the substrate is placed in the third chamber 205, which is not directly connected to the processing chamber 201. In one embodiment that can be combined with other embodiments, the substrate is flipped so that the back surface of the substrate faces upward, and defect counting measurements are performed, such as by using particle sensor 293a in the third chamber 205. The third chamber 205 may be a loading locking chamber, a transfer chamber, a buffer chamber, an interface chamber, or a factory interface chamber. This disclosure contemplates that particle sensor 293a may be disposed in the second chamber 203 or the processing chamber 205. This disclosure contemplates that one or more of the sensors 291a-291d in the second chamber 203 may be configured to perform the operations described for particle sensor 293a.

[0030] The third chamber 205 may include a flipping device that flips the substrate so that the back surface faces upward. The third chamber 205 may also include a robot, such as a robot 227 similar to that disposed in the second chamber 203.

[0031] Figure 3A This is a schematic partial cross-sectional view of a processing chamber 300 according to one embodiment. The processing chamber 300 can be used as... Figure 2 The system 200 shown includes a processing chamber 201. Processing chamber 300 is an etching chamber configured to perform etching operations on substrate 303. Suitable processing chambers applicable to the aspects disclosed herein include, for example, ENABLER, available from Applied Materials Inc., Santa Clara, California. ® SYM3 ® Or AdvantEdge ® Mesa ®Processing chamber. Processing chamber 300 includes a chamber body 302 and a cover 304 that enclose a processing volume 306. The chamber body 302 is made of aluminum, stainless steel, or other suitable material. The chamber body 302 includes sidewalls 308 and a bottom 320. A substrate inlet / outlet 331 is defined in the sidewalls 308 and selectively sealed by a slit valve 333 to facilitate the transfer of a substrate 303 into and out of the processing chamber 300. An exhaust port 326 is defined in the chamber body 302 and couples the processing volume 306 to a pump system 328. The pump system 328 typically includes one or more pumps and a throttle valve for evacuating and regulating the pressure of the processing volume 306 in the processing chamber 300. In one embodiment, the pump system 328 maintains the pressure within the processing volume 306 at an operating pressure typically between about 10 mTorr and about 500 Torr.

[0032] A cover 304 is securely supported on the sidewall 308 of the chamber body 302. The cover 304 can be opened to allow excess access into the processing volume 306 of the processing chamber 300. The cover 304 includes a window 324 for facilitating optical process monitoring. In one embodiment, the window 324 is made of quartz or other suitable material that transmits signals used by an optical monitoring system 340 mounted externally to the processing chamber 300. The optical monitoring system 340 is positioned to observe at least one of the processing volume 306 of the chamber body 302 and / or the substrate 303 located on the substrate support base assembly 348 through the window 324. The substrate 303 includes a front surface 305 and a back surface 307. The optical monitoring system 340 is coupled to the cover 304 and is used to measure various aspects of the substrate 303, such as defect counts of structures formed on the front surface 305 and / or defects (such as particles, e.g., contaminants) on the back surface 307. The optical monitoring system 340 can be used to create a defect map of defects (such as particles) on the back surface 307. The optical monitoring system 340 can be used as an endpoint detector, optical emission spectroscopy (OES), secondary ion mass spectrometry (SIMS), a signal detector, an optical detector, a combination of the above, and / or other suitable sensors or detectors associated with the processing chamber 300. The endpoint detector can be used to detect material in the processing chamber 300, such as material in the processing volume 306, for example, near the front surface 305 of the substrate 303. In operation, the optical monitoring system 340 can transmit signals to the controller 220 to facilitate its operation and determination.

[0033] Gas panel 358 is coupled to processing chamber 300 to supply processing gas and / or cleaning gas to processing volume 306. Figure 3AIn the illustrated embodiment, one or more inlets 332 (inlets 332', 332") are disposed in the cover 304 to allow gas to be delivered from the gas panel 358 to the processing volume 306 of the processing chamber 300. In one embodiment, the gas panel 358 is adapted to supply fluorinated processing gas to the processing volume 306 of the processing chamber 300 through inlets 332', 332". In one embodiment, the processing gas supplied from the gas panel 358 includes at least fluorinated gas, chlorine, carbon-containing gas, oxygen, nitrogen-containing gas, and chlorine-containing gas. Examples of fluorinated and carbon-containing gases include CHF3, CH2F2, and CF4. Other fluorinated gases may include one or more of C2F, C4F6, C3F8, and C5F8. Examples of oxygen-containing gases include O2, CO2, CO, N2O, NO2, O3, H2O, etc. Examples of nitrogen-containing gases include N2, NH3, N2O, NO2, etc. Examples of chlorine-containing gases include HCl, Cl2, CCl4, CHCl3, CH2Cl2, and CH3Cl. Suitable examples of carbon-containing gases include methane (CH4), ethane (C2H6), and ethylene (C2H4).

[0034] A spray head assembly 330 is coupled to the inner surface 314 of the cover 304. The spray head assembly 330 includes a plurality of orifices that allow gas to flow from inlets 332', 332" through the spray head assembly 330 into the processing volume 306 of the processing chamber 300, forming a predefined distribution across the entire surface of the substrate 303 being processed within the processing chamber 300. A remote plasma source 377 may optionally be coupled to a gas panel 358 to facilitate the separation of the gas mixture from the remote plasma before it enters the processing volume 306 for processing. An RF source power 343 is coupled to the spray head assembly 330 via a matching network 341. The RF source power 343 can range from approximately 50 kHz to approximately 200 kHz. It generates up to approximately 3000 watts of power at a tunable frequency in the MHz range. The spray head assembly 330 includes a region that transmits optical metering signals. The optical transmission region or channel 338 is adapted to allow the optical monitoring system 340 to observe the processing volume 306 and / or the substrate 303 located on the substrate support base assembly 348. The channel 338 may be a material, a hole, or a plurality of holes formed or disposed in the spray head assembly 330, which can substantially transmit the wavelength of the energy generated and reflected back by the optical monitoring system 340.

[0035] A substrate support base assembly 348 is disposed within a processing volume 306 of a processing chamber 300 below the spray head assembly 330. The substrate support base assembly 348 holds and clamps the substrate 303 during processing. The substrate support base assembly 348 typically includes a plurality of lifting rods (not shown) disposed therethrough, configured to lift the substrate 303 from the substrate support base assembly 348 and facilitate the exchange of the substrate 303 with a robot 227 extending into the processing chamber 300 through a substrate inlet / outlet 331. A liner 318 may tightly surround the outer periphery of the substrate support base assembly 348.

[0036] In one embodiment, the substrate support base assembly 348 includes a mounting plate 362, a base plate 364, and an electrostatic chuck (ESC) 366. One or more materials, such as bonding materials, may be disposed between the ESC 366 and the base plate 364. The ESC 366 is formed of a ceramic material such as AlN or Al2O3. Alternatively, the ESC 366 may be electrodes laminated between polymer sheets. The mounting plate 362 is coupled to the bottom 320 of the chamber body 302 and includes channels for routing utilities such as fluid, power lines, and sensor leads to the base plate 364 and the ESC 366. The ESC 366 includes at least one electrode 380 for clamping a substrate 303 to the ESC 366 to hold the substrate 303 below the spray head assembly 330. Clamping power supply 382 is coupled to ESC 366 and operable to apply a clamping voltage to electrode 380 to generate an electrostatic force (clamping force) that clamps substrate 303 to clamping interface 311 of ESC 366. Clamping power supply 382 is configured to apply a clamping voltage up to 5000 volts to ESC 366, such as in the range of 0 volts to 2000 volts (e.g., target clamping voltage, initial clamping voltage, and adjusted clamping voltage).

[0037] At least one of the base plate 364 or ESC 366 may include at least one optional embedded heater 376, at least one optional embedded isolator 374, and multiple conduits 368, 370 to control the lateral temperature distribution of the substrate support base assembly 348. The conduits 368, 370 are fluidly coupled to a fluid source 372, in which a temperature-regulating fluid is circulated. The heater 376 is regulated by a power supply 378. The conduits 368, 370, and heater 376 are used to control the temperature of the base plate 364, thereby heating and / or cooling the ESC 366, and ultimately controlling the temperature distribution of the substrate 303 disposed thereon. Multiple temperature sensors 390, 392 may be used to monitor the temperature of the ESC 366 and the base plate 364. In one embodiment, the substrate support base assembly 348 is configured as a cathode, and an electrode 380 or a second electrode is coupled to multiple RF bias power supplies 384, 386. RF bias power supplies 384 and 386 are coupled between an electrode 380 disposed in the substrate support base assembly 348 and another electrode (such as the spray head assembly 330 or the top plate (cover 304) of the chamber body 302). The RF bias power excites and sustains a plasma discharge formed by a gas disposed in the processing region of the chamber body 302. The dual RF bias power supplies 384 and 386 are coupled to the electrode 380 disposed in the substrate support base assembly 348 via a matching circuit 388. The signal generated by the RF bias power supplies 384 and 386 is delivered to the substrate support base assembly 348 via a single feeder through the matching circuit 388 to ionize the gas mixture provided in the processing chamber 300, thereby providing the ion energy required to perform deposition operations, etching operations, or other operations. The RF bias power supplies 384 and 386 are capable of generating RF signals with frequencies from about 50 kHz to about 200 MHz and power between about 0 watts and about 5000 watts. An additional bias power supply 389 can be coupled to electrode 380 to control the characteristics of the plasma.

[0038] In one operating mode, substrate 303 is supported on substrate support base assembly 348 in processing chamber 300 at ESC366. Process gas and / or gas mixture is introduced into chamber body 302 from gas panel 358 via spray head assembly 330. Vacuum pump system 328 maintains pressure inside chamber body 302 while removing byproducts.

[0039] Figure 3B According to one implementation method Figure 3AAn enlarged schematic diagram of the processing chamber 300 is shown. The locking interface 311 includes an external support surface 344. The ESC 366 includes a recessed surface 345 disposed inside the external support surface 344 and a plurality of bosses 346 projecting upward relative to the recessed surface 345. The locking interface 311 includes an upper surface 347 of the plurality of bosses 346. The ESC 366 includes a plurality of gas channels 349, such as grooves, between the plurality of bosses 346. The plurality of gas channels 349 are used to flow back-side gas G1 to the back-side surface 307 of the substrate 303. The plurality of gas channels 349 are fluidly connected to a gas source supplying the back-side gas G1. The back-side gas G1 may be helium or other suitable gas. In operation, the back-side gas G1 is supplied to the gas channels under controlled pressure to enhance heat transfer between the ESC 366 and the substrate 303. Backside gas G1 may be provided during the first processing operation of method 100 (operation 102), the second processing operation of method 100 (operation 108), and the ejection operation of method 100. Multiple gas channels 349 may be fluidly connected to a gas source via at least one or more gas openings 351 formed in ESC 366.

[0040] During the ejection operation described in method 100, an initial clamping voltage applied using clamping power supply 382 is ramped up or ramped down until the clamping voltage reaches a leakage voltage, at which the back-side gas G1 leaks through the outer edge 309 of substrate 303 at a leakage rate exceeding a leakage threshold. When the back-side surface 307 is at least partially separated from the outer support surface 344, the back-side gas G1 leaks between the back-side surface 307 and the outer support surface 344 (e.g., Figure 3B (As shown by the dashed line in the diagram). After the ejection operation, substrate 303 can be removed from the processing chamber 300, and a second substrate (similar to substrate 303) can be placed on ESC 366, so that a second processing operation is performed on the second substrate in the processing chamber 300.

[0041] As described above, defect counts can be measured outside the processing chamber 300 and in different tools or chambers (such as the measurement chamber). Particle counts can be used to create defect count maps. Defects can be detected from... Figure 3BThe backside gas G1 discussed herein is deposited on the backside surface 307, and / or as a result of contact between the backside surface 307 and other components such as the lifting rod, boss 346, and / or external support surface 344. Particle sensor 293b is configured to measure the leakage rate of leaked backside gas G1 during ejection operation. One or more laser sensors 280 disposed in the second chamber 203 of system 200 are aligned below the substrate inlet / outlet 331 such that as the substrate 303 is moved toward (e.g., into) and away from (e.g., out) the processing chamber 300, the substrate 303 moves past light emitted by the one or more laser sensors 280. The one or more laser sensors 280 are configured to determine the center of the substrate 303 whenever the substrate 303 moves past light emitted by the one or more laser sensors 280. The one or more laser sensors 280 are used to determine the pre-processing position of the center of the substrate 303 as the substrate is moved toward (e.g., into) the processing chamber 300. As the substrate is moved away from (e.g., away from) the processing chamber 300, one or more laser sensors 280 are used to determine the post-processing position of the center of the substrate 303. This disclosure envisions that the sensor and / or operation of particle sensors 293a, 293b, and / or one or more laser sensors 280 can be incorporated into the optical monitoring system 340.

[0042] This disclosure envisions that one or more laser sensors 280 may be disposed in the processing chamber 300, such as disposed below the substrate inlet / outlet 331 and mounted on the side wall 308.

[0043] Controller 220 is coupled to processing chamber 300 to control the operation of processing chamber 300. Controller 220 includes a central processing unit (CPU) 231, a memory 232 containing instructions, and support circuitry 233 for CPU 231. CPU 231 can be any form of general-purpose computer processor that can be used in an industrial environment. Controller 220 controls processing chamber 300 directly or via other computers and / or controllers (not shown) coupled to processing chamber 300. Controller 220 is any form of general-purpose computer processor used in an industrial environment to control various chambers and devices and their subprocessors in or on. Memory 232 or non-transitory computer-readable medium is one or more readily available memories, such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, flash drive, or any other form of local or remote digital storage. Support circuitry 233 is coupled to CPU 231 to support CPU 231. Support circuitry 233 includes cache, power supply, clock circuitry, input / output circuitry systems, and subsystems, etc. The substrate processing parameters and operations are stored as software routines in memory 232, which are executed or invoked to turn controller 220 into a dedicated controller to control the operation of processing chamber 300. Controller 220 is configured to implement any of the methods described herein. When executed, instructions stored in memory 232 cause one or more of operations 102-108 of method 100 to be performed.

[0044] The controller 220 executes multiple instructions, including instructions to activate one or more sensors 291a-291d, one or more sensors 293a, 293b, and / or one or more laser sensors 280 to obtain measurement values. Instructions in the controller 220's memory 232 may include one or more machine learning / artificial intelligence algorithms that can be executed in addition to the operations described herein. As an example, the machine learning / artificial intelligence algorithm executed by the controller 220 may improve and / or modify operating parameters based on one or more sensor measurements taken by sensors 291a-291d, 293a, 293b, and / or 280. Operating parameters may include, for example, defect counts, leakage rates, processing shifts, and / or adjusted clamping voltages—each described above. The machine learning / artificial intelligence algorithm can be used with multiple electrostatic chucks (ESCs) to improve clamping operations between multiple ESCs over the lifespan of the ESCs.

[0045] Figure 3C According to one implementation method Figure 3AThe diagram shows an enlarged view of a processing chamber 300, in which a sensor substrate assembly 353 is located. A robot 227 has been used to lift the substrate 303 from the ESC 366 and remove it from the processing chamber 300. The robot 227 is used to place the sensor substrate assembly 353 onto the ESC 366. The sensor substrate assembly 353 includes one or more substrates, such as a first substrate 355 and a second substrate 357 located on top of the first substrate 355. The surfaces of the first substrate 355 and the second substrate 357 define a cavity 359. A plurality of sensors 360 are located in the cavity 240 and between the first substrate 355 and the second substrate 357. The second substrate 357 is attracted to the ESC 366 by a clamping voltage, causing the second substrate 357 to apply compressive forces to the plurality of sensors 360. The applied forces exerted by the ESC 366 on the sensor substrate assembly 353 during the application of the clamping voltage are measured by monitoring the plurality of sensors 360. The first substrate 355 and the second substrate 357 may be formed of silicon. Multiple sensors 360 are pressure sensors, such as spring gauge sensors, piezoelectric sensors, and / or microelectromechanical systems (MEMS) sensors. The sensor substrate device 353 includes a computing module 361. The computing module 361 may include components (e.g., a processor and / or memory) for calculating, recording, and / or transmitting measurements of the applied force exerted on the sensor substrate device 353 by the ESC 366 during the application of the clamping voltage. For example, the measurements may be transmitted to the controller 220 using a transmitter or a wired connection. The measurements may be stored in the sensor substrate device 353 and subsequently downloaded to the controller 220.

[0046] Sensor 360 is mechanically and electrically coupled between a first substrate 355 and a second substrate 357. Each sensor 360 is electrically coupled to a corresponding first conductive pad 363 on the first substrate 355 and / or a second conductive pad 365 on the second substrate 357. The conductive pads 363 and 365 may be electrically coupled to a computing module 361 (e.g., via conductive traces (not shown)). This disclosure contemplates omitting either the first conductive pad 363 or the second conductive pad 365.

[0047] Figure 4 This is a schematic diagram of a defect count chart 400 of the back surface 307 of a substrate 303 obtained after a first processing operation, according to one embodiment. The back surface 307 has a plurality of defects 401 present thereon. The defect count chart 400 includes a defect count of the plurality of defects 401. The plurality of defects 401 may include contaminant particles, scratches, and / or debris. The plurality of defects 401 may be deposited on the back surface 307 from back-side gas deposition and / or as a result of contact between the back surface 307 and other components such as lifting rods and / or ESC surfaces.

[0048] Figure 5It is based on the support of one implementation method Figure 3A A schematic top view of the substrate 303 on the robot blade 226 of the robot 227 shown. As the robot blade 226 and the substrate 303 supported thereon extend toward the substrate inlet 331, toward the ESC 336, and into the processing chamber 300, the robot blade 226 and the substrate 303 move in a first direction D1 in the XY plane. As the robot blade 226 and the substrate 303 move in the first direction D1, the substrate 303 moves past light emitted by one or more laser sensors 280 in the second chamber 203. When the substrate 303 moves past the light emitted by one or more laser sensors 280 in the first direction D1, the substrate 303 (e.g., the outer periphery of the substrate 303) blocks the light, and one or more laser sensors 280 are triggered. One or more laser sensors 280 are triggered when the emitted light is no longer reflected and collected by one or more laser sensors 280 at the same level as before the substrate 303 blocked the light. The light blocked by the substrate 303 is used to measure a plurality of first positions 501-504 along the outer periphery 510 of the substrate 303. Each of the plurality of first positions 501-504 is located in the XY plane and has a corresponding X coordinate (X1) and Y coordinate (Y1). The first positions 501-504 are used to calculate the preprocessing position 505 at the center of the substrate 303 before performing the first processing operation.

[0049] As the robot blade 226 and the substrate 303 supported thereon are withdrawn from the processing chamber 300, exit the ESC 366, and exit the substrate inlet / outlet 331, the robot blade 226 and the substrate 303 move in a second direction D2 in the XY plane. As the robot blade 226 and the substrate 303 move in the second direction D2, the substrate 303 moves past light emitted by one or more laser sensors 280. When the substrate 303 moves in the second direction D2 past the light emitted by one or more laser sensors 280, the substrate 303 (e.g., the outer periphery of the substrate 303) blocks the light, and one or more laser sensors 280 are triggered. One or more laser sensors 280 are triggered when the emitted light is no longer reflected and collected by one or more laser sensors 280 at the same level as before the substrate 303 blocked the light. The light blocked by the substrate 303 is used to measure a plurality of second positions 511-514 along the outer periphery 510 of the substrate 303. Each of the plurality of second positions 511-514 is located in the XY plane and has a corresponding X coordinate (X2) and Y coordinate (Y2). The second positions 511-514 are used to calculate a post-processing position 515 (e.g., a shifted position) of the center of the substrate 303 after a first processing operation on the substrate 303. A post-processing shift 520 between the post-processing position 515 and the pre-processing position 505 is determined by determining the distance between the post-processing position 515 and the pre-processing position 505. The post-processing shift 520 may include an X-axis shift and a Y-axis shift. The post-processing shift 520 is the difference (such as distance) between the pre-processing position 505 and the post-processing position 515.

[0050] For each of the preprocessing positions 505 and postprocessing positions 515, the corresponding first positions 501-504 and second positions 511-514, together with known parameters of the substrate 303 (such as radius R1), are used in a Pythagorean calculation to calculate the preprocessing positions 505 and 515. In one example, half of the first Y distance DY1 between the first positions 501 and 503, together with radius R1, is used in a Pythagorean calculation to calculate the first X distance DX1 between the first Y distance DY1 and the preprocessing position 505 at the center of the substrate 303. Half of the second Y distance DY2 between the first positions 502 and 504, together with radius R1, is used in a Pythagorean calculation to calculate the second Y distance DY2 and the second X distance DX2 between the second Y distance DY2 and the preprocessing position 505 at the center of the substrate 303.

[0051] Each of the preprocessing position 505 and the postprocessing position 515 can be determined relative to a reference point 530 to determine the postprocessing shift 520. The reference point 530 can be a reference point set along the robot blade 226 (such as along the central axis 531 of the robot blade 226).

[0052] Figure 6 It is based on the support of one implementation method Figure 3A A schematic side view of the base plate 303 on the robot blade 226 of the robot 227 shown. A central cover 30 defining the upper boundary of the volume 218 of the second chamber 203 (e.g., a transfer chamber) has a generally circular opening 32 sealed by a window 34, which may be a thick plastic glass plate, thereby allowing observation of the interior of the second chamber 203 from above.

[0053] One or more laser sensors 280 can detect when the outer periphery of substrate 303 blocks the light beam 36 passing through the second chamber 203. This can be achieved in various ways. For example, the light source can be positioned above the central cover 30 to guide the light beam through window 34 onto the surface of the optical detector. When the light beam is incident on the surface of the optical detector, the output of the optical detector has a first value, and when the light beam is not incident on the optical detector (such as when the light beam is blocked by substrate 303), the output of the optical detector has a second value. When the outer periphery of substrate 303 passes through the light beam path 36, thereby blocking the path from the light source (one or more laser sensors 280) to the detector, the output of the detector changes from the first value to the second value. By recording the position of robot 227 when the detector output value changes, the center information of substrate 303 can be determined. A controller 68 is provided in system 200. The controller 68 derives the center information of substrate 303 from the information provided by robot 227 and one or more laser sensors 280. Figure 2 As schematically shown, controller 68 can be coupled to controller 220. Controller 68 can communicate with controller 220 or can be integrated into controller 220.

[0054] One or more laser sensors 280 emit a beam path 36 and output a signal of a first value when the beam path 36 is uninterrupted, and output a signal of a second value when the beam path 36 is blocked (such as by a substrate 303). Each of the one or more laser sensors 280 includes a reflection sensor 38, which has a light source and a detector in a single housing. The reflection sensor 38 may include a Comet 100 visible-red light reflection sensor, DC model 14102A6517, manufactured by Eaton Corporation of Everett, Washington. Figure 6One or more laser sensors 280 are shown, located outside a second chamber 203 along with a light source and a detector. Light 36 from a reflector 38 is directed through a window 34 in a central cover 30 into the second chamber 203 and toward the base of the second chamber 203. Light 36 is reflected back from a reflector 40 to the reflector 38, and a detector within the reflector 38 detects the returned beam. In one embodiment, the reflector 40 includes a corner prism. A corner prism has the property of reflecting all light rays incident within a given solid angle from the normal to the corner prism surface back to the light source (e.g., the reflector sensor). A corner prism typically has a cubic form cut along the diagonal plane of a cube, such that only one corner of the cube remains intact. When used as a reflector, the corner prism is configured such that light incident on the diagonal plane is generally directed to the remaining corner of the cube. Even if the surface of the corner prism is not perpendicular to the incident light rays, light rays incident on the surface of the corner prism reflector are reflected back to the light source. Therefore, when used as reflector 40 of this disclosure, the corner prism does not need to be precisely aligned. This disclosure envisions other reflectors, such as mirrors, that can be used with reflector 40. The corner prism may be, for example, a corner prism manufactured by Rolyn Optics Company of Covina, California, with part number 42.0015.

[0055] A reflection sensor 38 is mounted to window 34 via a holder 44, which allows for minor alignment adjustments of the reflection sensor 38. A reflector 40 is mounted to the bottom of the cover of the second chamber 203 via a stabilizing holder 46. Holders 44 and 46 are configured such that the optical path between the reflection sensor 38 and the reflector 40 will be in the robot blade 226 away from the robot blade 226 (…). Figure 6 The edge (not shown) intersects with the outer periphery of the substrate 303 being moved by the robot blade 226 at a location where the edge (e.g., outside the edge) is set.

[0056] One or more laser sensors 280 offer numerous advantages when used in the system 200 of this application. The reflection sensor 38 preferably emits and detects modulated visible light laser light (such as red light), allowing the reflection sensor 38 to distinguish the beam 36 from the visible light background radiation typically present in the wafer processing environment. Synchronizing the optical detector within the reflection sensor 38 with the modulation signal used to modulate the input red light signal reduces the likelihood of false signal detection. The detection geometry and orientation of the one or more laser sensors 280 further reduce the possibility of erroneous signals. The normals to the surfaces of the reflection sensor 38, the beam path 36, and the reflector 40 are all positioned at an angle to the surface of the window 34 in the center cover 30, thereby reducing the likelihood of detecting light reflected by the window 34 or the wafer 10. This geometry also reduces the likelihood of background or ambient light sources being falsely detected by the reflection sensor 38 as substrate position signals.

[0057] The reflection sensor 38 has a further advantage: when the intensity of light incident on the detector is above or below a predetermined threshold level, the detector output switches between two signal levels corresponding to typical logic 1 and 0 in a computer system. Therefore, the output of the reflection sensor 38 is readily compatible with the controller 220 transmitting data to the control board and the system 200 of this disclosure. If the signal output of the optical detector used is not directly compatible with the computer, a method (such as a signal conversion method) transforms the detector output into a computer-compatible signal.

[0058] The benefits of this disclosure include accurate determination of voltage regulation, improved clamping voltage, and maintenance of target clamping force; enhanced processing operation and improved processing accuracy; reduced or eliminated chances of substrate adhesion and / or substrate breakage; reduced or eliminated chances of substrate ejection; reduced occurrence of front-side and back-side defects; and increased service life of the electrostatic chuck. The benefits of this disclosure also include reduced operation time, reduced replacement and operating costs, reduced machine downtime, reduced resource expenditure, and increased throughput. The techniques described herein can determine whether the clamping force applied to the substrate has changed when the same clamping voltage is applied, and help improve force control between substrates throughout the ESC life. Such variations in clamping force may be caused by contaminant deposition on ESC surfaces (such as recessed surface 345), roughening of ESC surfaces (such as exposure to plasma), and / or gradual removal of ESC material (such as corrosion or wear of portions of the multiple bosses 346 occurring during processing iterations). The benefits of this disclosure also include the use of existing chamber equipment to accurately determine whether an adjusted clamping voltage is needed based on the occurrence of processing displacement.

[0059] Compared to conventional operations involving measuring voltage on the substrate and operations involving measuring pressure or force on the substrate, the technique described herein achieves the aforementioned benefits. The technique described herein contributes to superior results compared to other operations in terms of efficiency and accuracy in maintaining the target clamping voltage. As an example, the technique described herein contributes to superior results because it accurately accounts for the clamping force applied to the substrate, rather than relying on current or voltage measurements within the chamber. As another example, the technique described herein can determine in real-time and accurately when voltage regulation is required.

[0060] While the foregoing describes embodiments of this disclosure, other embodiments of this disclosure may be designed without departing from the basic scope of this disclosure. This disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted into one or more of the other aspects described. The scope of this disclosure is defined by the appended claims.

Claims

1. A method for clamping a substrate, comprising the following steps: The substrate is subjected to a first processing operation in a processing chamber, the first processing operation including the following steps: When the substrate is supported on the electrostatic chuck, a clamping voltage is applied to the electrostatic chuck in the processing chamber; Determining that a processing shift has occurred includes: Determining whether the center of the substrate has moved from the preprocessing position before the first processing operation to the postprocessing position includes: The substrate is lifted from the electrostatic chuck; After the first processing operation is performed, the substrate is moved through light emitted by multiple sensors; Determine multiple locations along the outer periphery of the substrate, the multiple locations being located in the XY plane; The post-processing position of the center is calculated using the plurality of positions; and Determine that the distance between the post-processing position and the pre-processing position meets or exceeds a predetermined threshold; and The adjusted clamping voltage is determined based on the occurrence of the processing shift.

2. The method of claim 1, wherein the step of determining the adjusted clamping voltage comprises the following steps: The clamping force applied to the sensor substrate device is measured when the sensor substrate device is supported on the electrostatic chuck.

3. The method of claim 1, wherein the predetermined threshold is in the range of 0.5 mm to 10 mm.

4. The method of claim 3, wherein the step of moving the substrate past the light emitted by the plurality of sensors includes the following steps: The robot blade is moved while the substrate is supported on the robot blade.

5. The method of claim 1, wherein the step of determining the adjusted clamping voltage comprises the following steps: The ejection operation involves ejecting a workpiece, the workpiece including the substrate or the second substrate, and the ejection operation includes the following steps: An initial clamping voltage is applied to the electrostatic chuck supporting the workpiece; To direct the back-side gas flow toward the back-side surface of the workpiece; and The initial clamping voltage is increased or decreased to a leakage voltage, at which the back-side gas leaks through the outer edge of the workpiece at a leakage rate exceeding the leakage threshold.

6. The method of claim 5, wherein the leakage threshold is in the range of 2.0 sccm to 5.0 sccm.

7. The method of claim 5, wherein the adjusted clamping voltage is determined by adding a safety voltage margin to the leakage voltage or subtracting the safety voltage margin from the leakage voltage.

8. The method of claim 7, further comprising the following steps: A second processing operation is performed on the substrate, the second substrate, or the third substrate in the processing chamber. The second processing operation includes the following steps: When the substrate, the second substrate, or the third substrate is supported on the electrostatic chuck, the adjusted clamping voltage is applied to the electrostatic chuck.

9. A non-transitory computer-readable medium for performing a clamping operation, the non-transitory computer-readable medium comprising instructions that, when executed, cause a plurality of operations to be performed, the plurality of operations comprising the following steps: A first processing operation is performed on the substrate in a processing chamber, the first processing operation including: When the substrate is supported on the electrostatic chuck, a clamping voltage is applied to the electrostatic chuck in the processing chamber; Determining that a processing shift has occurred includes: Determining whether the center of the substrate has moved from the preprocessing position before the first processing operation to the postprocessing position includes: The substrate is lifted from the electrostatic chuck; After the first processing operation is performed, the substrate is moved through light emitted by multiple sensors; Determine multiple locations along the outer periphery of the substrate, the multiple locations being located in the XY plane; The post-processing position of the center is calculated using the plurality of positions; and Determine that the distance between the post-processing position and the pre-processing position meets or exceeds a predetermined threshold; and The adjusted clamping voltage is determined based on the occurrence of the processing shift.

10. The non-transitory computer-readable medium of claim 9, wherein the step of determining the adjusted clamping voltage includes the following steps: The clamping force applied to the sensor substrate device is measured when the sensor substrate device is supported on the electrostatic chuck.

11. The non-transitory computer-readable medium of claim 9, wherein the predetermined threshold is in the range of 0.5 mm to 10 mm.

12. The non-transitory computer-readable medium of claim 11, wherein the step of moving the substrate past the light emitted by the plurality of sensors comprises the following steps: The robot blade is moved while the substrate is supported on the robot blade.

13. The non-transitory computer-readable medium of claim 9, wherein the step of determining the adjusted clamping voltage includes the following steps: The ejection operation involves ejecting a workpiece, the workpiece including the substrate or the second substrate, and the ejection operation includes the following steps: An initial clamping voltage is applied to the electrostatic chuck supporting the workpiece; To direct the back-side gas flow toward the back-side surface of the workpiece; and The initial clamping voltage is increased or decreased to a leakage voltage, at which the back-side gas leaks through the outer edge of the workpiece at a leakage rate exceeding the leakage threshold.

14. The non-transitory computer-readable medium of claim 13, wherein the leakage threshold is in the range of 2.0 sccm to 5.0 sccm.

15. The non-transitory computer-readable medium of claim 13, wherein the adjusted clamping voltage is determined by adding a safety voltage margin to the leakage voltage or subtracting the safety voltage margin from the leakage voltage.

16. The non-transitory computer-readable medium of claim 15, wherein the plurality of instructions further includes performing a second processing operation on the substrate, the second substrate, or the third substrate in the processing chamber, the second processing operation comprising the following steps: When the substrate, the second substrate, or the third substrate is supported on the electrostatic chuck, the adjusted clamping voltage is applied to the electrostatic chuck.

17. A system for processing a substrate, comprising: A processing chamber, the processing chamber comprising a processing volume; An electrostatic chuck is disposed in the processing chamber; A robot, the robot including robot blades, and configured to extend the robot blades into and retract the processing volume; The controller includes instructions that, when executed, cause: The processing chamber performs a first processing operation on the substrate within the processing chamber, the first processing operation including: When the substrate is supported on the electrostatic chuck, a clamping voltage is applied to the electrostatic chuck; Multiple laser sensors are configured to measure multiple locations along the outer periphery of the substrate, the multiple locations being located in the XY plane; When the instruction is executed, it further causes: The processor determines that a processing shift has occurred, wherein determining that the processing shift has occurred includes: Determining whether the center of the substrate has moved from its preprocessing position before the first processing operation to its postprocessing position involves a postprocessing shift, wherein determining whether the center of the substrate has moved by the postprocessing shift includes: The substrate is lifted from the electrostatic chuck; After the first processing operation is performed, the substrate is moved through light emitted by multiple sensors; The post-processing position of the center is calculated using the plurality of positions; and Determine that the distance between the post-processing position and the pre-processing position meets or exceeds a predetermined threshold; and The processor determines the adjusted clamping voltage based on the occurrence of the processing shift.

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