Process for calculating wafer thickness from wafer mapping

Abstract

1. A method of operating a substrate processing system, the substrate processing system including a substrate processing chamber, a substrate storage container, and a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber, the method including: detecting a lower edge and an upper edge of the substrate; calculating a thickness of the substrate based on the detected lower edge and upper edge of the substrate; comparing the calculated thickness of the substrate to an expected thickness of the substrate; (i) controlling the robot to transfer the substrate into the substrate processing chamber if the calculated thickness matches the expected thickness; and (ii) generating an alert indicating the thickness discrepancy if the calculated thickness does not match the expected thickness.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. patent application Ser. No. 18 / 071,400, filed Nov. 29, 2022, the entire contents of which are incorporated herein by reference. [Background technology]

[0002]

[0002] The manufacture of semiconductor devices typically involves many different process steps performed in a semiconductor manufacturing facility by several different types of tools. For example, to complete the fabrication of integrated circuits on a semiconductor wafer, the wafer may be transferred to and processed by a series of tools including chemical vapor deposition tools, physical vapor deposition tools, etching tools, chemical-mechanical polishing tools, photolithography tools, and metrology tools, among others.

[0003] Historically, semiconductor manufacturers typically processed wafers of a particular diameter (e.g., 200 mm or 300 mm diameter wafers) in a series of tools specifically designed to work with wafers of that diameter, and all wafers of that diameter had the same thickness. For example, 200 mm wafers processed in one series of tools might all be 700 microns thick, while 300 mm wafers processed in another series of tools might all be 775 microns thick. Thus, any given tool was typically used to process only wafers of a particular, known thickness.

[0004]

[0004] In recent years, however, various semiconductor manufacturers have begun processing substrates such as silicon wafers to form various types of integrated circuits and devices, some of which are fabricated on semiconductor wafers having various thicknesses. For example, a semiconductor manufacturer may manufacture some products on a first set of 200 mm silicon wafers that are 700 microns thick, other products on a second set of 200 mm silicon wafers that are 300 microns thick, and still other products on a third set of 200 mm silicon wafers that are 1,400 microns thick.

[0005] A given processing tool may be installed within a manufacturing facility to accept and process a first set of wafers (700 micron thick wafers), a second set of wafers (300 micron thick wafers), and a third set of wafers (1,400 micron thick wafers), but adjustments may be required to ensure the tool is capable of properly processing each of the wafers of various thicknesses. If the necessary adjustments are not properly made, the wafers may be damaged during transfer to or processing within the tool, or steps associated with processing the wafers within the tool may not be performed properly.

[0006] To prevent wafers of the wrong thickness from being introduced into a given tool, some semiconductor manufacturers require operators to manually control the tool settings and set the tool for the appropriate thickness of the wafers to be processed by the tool. Such an approach is prone to human error. Summary of the Invention

[0007]

[0007] Embodiments of the present disclosure provide methods and systems for automatically detecting the thickness of a sample prior to transferring the sample to an evaluation tool. In some embodiments, if the sample is thicker or thinner than what the tool is configured to process, an alert or signal can be generated indicating a discrepancy between the actual and expected thickness of the sample being transferred to the tool. In some embodiments, the tool can respond to the signal by, for example, preventing the sample from being transferred to the tool or by making one or more adjustments within the tool to configure the tool to accept and process a sample of the actual measured thickness. While embodiments of the present disclosure can be used to detect the thickness of a variety of different types of samples, some embodiments are particularly useful in detecting the thickness of samples that are semiconductor wafers or similar specimens.

[0008] In some embodiments, a method of operating a substrate processing system is provided. The substrate processing system may include a substrate processing chamber, a substrate storage container, and a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber. The method may include detecting lower and upper edges of the substrate, calculating a thickness of the substrate based on the detected lower and upper edges of the substrate, comparing the calculated thickness of the substrate to an expected thickness of the substrate, (i) controlling the robot to transfer the substrate into the substrate processing chamber if the calculated thickness matches the expected thickness, and (ii) generating an alert indicating the thickness discrepancy if the calculated thickness does not match the expected thickness.

[0009] In some embodiments, a substrate processing chamber is provided that includes a substrate processing chamber, a substrate storage container, a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber, as well as a processor and a memory coupled to the processor. The memory may include a plurality of computer-readable instructions that, when executed by the processor, cause the system to: detect lower and upper edges of the substrate; calculate a thickness of the substrate based on the detected lower and upper edges of the substrate; compare the calculated thickness of the substrate to an expected thickness of the substrate; and (i) control the robot to transfer the substrate into the substrate processing chamber if the calculated thickness matches the expected thickness; and (ii) generate an alert indicating the thickness discrepancy if the calculated thickness does not match the expected thickness.

[0010] In some embodiments, a non-transitory computer-readable memory storing computer-readable instructions for operating a substrate processing system including a substrate processing chamber, a substrate storage container, and a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber is provided. The system may further include a processor operably coupled to the substrate processing chamber. The computer-readable instructions, when executed by the processor, cause the processor to control the substrate processing system to detect lower and upper edges of the substrate, calculate a thickness of the substrate based on the detected lower and upper edges of the substrate, compare the calculated thickness of the substrate to an expected thickness of the substrate, and (i) control the robot to transfer the substrate into the substrate processing chamber if the calculated thickness matches the expected thickness, and (ii) generate an alert indicating the thickness discrepancy if the calculated thickness does not match the expected thickness.

[0011] Various implementations of the method, system, or computer-readable instructions may include one or more of the following features. Detecting the lower and upper edges of the substrates may occur during a substrate mapping process in which the quantity of substrates and the position of each substrate within a substrate storage container are mapped. The robot may include a robot arm having a sensor configured to detect the lower and upper edges of the substrates. The robot arm may include a first finger and a second finger spaced apart from each other in opposing relationship. The sensor may include a laser and a photodetector. The laser may be positioned near a distal end of the first finger, and the photodetector may be positioned near a distal end of the second finger. The laser and the photodetector may be aligned with each other such that the photodetector can detect a laser beam emitted from the laser. Detecting the lower and upper edges of the substrate can be performed when a robot arm scans vertically across the substrate storage container, the robot arm positioned such that the outer periphery of the substrate passes between the first and second fingers to interfere with the laser beam during the scanning process. The system can further include a controller operably coupled to control functions of the substrate processing system, and a computer-readable memory coupled to the controller. The substrate processing chamber can be used for defect review, classification, and analysis, and can include a focused ion beam (FIB) column and a scanning electron microscope (SEM) column. The substrate can be a semiconductor wafer.

[0012] Additional implementations may further include one or more of the following features. The method may further include inputting an expected substrate thickness into a computer-readable memory via a user interface before detecting the lower and upper edges of the substrate. The method may further include setting or adjusting one or more components of the substrate processing chamber based on the expected thickness of the substrate before detecting the lower and upper edges of the substrate. The method may further include preventing the substrate from being transferred into the substrate processing chamber if the calculated thickness does not match the expected thickness. The method may further include setting or adjusting one or more components of the substrate processing chamber based on the calculated thickness if the calculated thickness does not match the expected thickness.

[0013]

[0013] For a better understanding of the nature and advantages of the present disclosure, reference should be made to the following description and the accompanying figures. It should be understood, however, that each figure is provided for illustrative purposes only and is not intended as a definition of the limits of the scope of the present disclosure. Furthermore, as a general rule, unless otherwise clear from the description, when elements in different figures use the same reference numerals, those elements are generally identical or at least similar in function or purpose. [Brief explanation of the drawings]

[0014] [Figure 1A] 1A-1C are simplified top views of substrates that may be processed in a tool according to embodiments disclosed herein. [Figure 1B] 1A-1C are simplified side views illustrating different widths of three different substrates that may be processed in a tool according to embodiments disclosed herein. [Figure 2] 1 is a simplified diagram of a substrate processing system according to some embodiments. [Figure 3A] 1 is a simplified diagram of a substrate transfer mechanism and a substrate storage container according to some embodiments. [Figure 3B] 3B is a simplified top view of a robot arm of the substrate transfer mechanism shown in FIG. 3A, according to some embodiments. [Figure 4] FIG. 3C is a simplified top view illustrating the positional relationship between the robot arm shown in FIGS. 3A and 3B and the perimeter of a sample whose thickness is being measured according to some embodiments. [Figure 5] 1 is a flowchart illustrating steps associated with a method according to some embodiments. [Figures 6A-6D] 6A-6C are simplified schematic diagrams illustrating the positional relationship between a substrate transfer mechanism and a substrate during various steps of the method illustrated in FIG. 5, according to some embodiments. [Figure 7] 1 is a flowchart illustrating steps associated with a method according to some embodiments. [Figure 8] FIG. 1 is a simplified diagram of a sample evaluation system according to some embodiments of the present disclosure. [Figure 9] 1 is a simplified diagram of areas on a semiconductor wafer that can be transferred to a substrate processing chamber, according to some embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0015]

[0025] As mentioned above, some semiconductor manufacturers process substrates of various thicknesses within the same tool or toolset within a manufacturing facility. For example, FIG. 1A is a simplified top view of a substrate 100 that can be processed within a semiconductor or similar manufacturing facility. The substrate 100 may be representative of the substrates ## described below with respect to FIG. 1B. By way of non-limiting example, the substrate 100 may be a silicon substrate, a gallium arsenide (GaAs) substrate, an indium phosphide (InP) substrate, or a sapphire substrate, among others. The substrate 100 may be generally circular and very thin relative to its diameter, and as such may be referred to herein as a "wafer."

[0016]

[0026] 1B is a simplified side view showing various substrates 100, each having the same general shape and diameter but varying thicknesses. For example, as shown, substrate 100a is thinner than substrate 100b, which is in turn thinner than substrate 100c. While embodiments of the present invention are not limited to processing substrates of any particular thickness, by way of non-limiting example, in some embodiments, substrate 100a may have a thickness ta of approximately 300 microns, substrate 100b may have a thickness tb of approximately 700 microns, and substrate 100c may have a thickness tc of approximately 1,400 microns. Although the various substrates 100a, 100b, 100c each have the same overall shape and can potentially be processed in the same tool for a particular operation, the different thicknesses of the substrates may require the tool to have one or more components that need to be set up or adjusted differently depending on which of the substrates 100a, 100b, or 100c (or a series of substrates 100a, 100b, or 100c) is being transferred into the tool.

[0017]

[0027] Embodiments of the present disclosure provide methods and systems for automatically detecting the thickness of a substrate (e.g., substrates 100a, 100b, and 100c) before transferring the substrate to a substrate processing tool. In some embodiments, if the sample is thicker or thinner than what the tool is configured to process, an alert or signal can be generated indicating a discrepancy between the actual and expected thickness of the sample being transferred to the tool. In some embodiments, the tool can respond to the signal by, for example, preventing the substrate from being transferred into the tool or by making one or more adjustments within the tool to configure the tool to accept and process a substrate of the actual, measured thickness. While embodiments of the present disclosure can be used to detect the thickness of a variety of different types of substrates or samples, some embodiments are particularly useful in detecting the thickness of substrates that are semiconductor wafers or similar specimens.

[0018] Exemplary Substrate Processing System

[0028] For a better understanding and appreciation of the present disclosure, reference is now made to FIG. 2, which is a simplified schematic illustration of a substrate processing system 200 according to embodiments disclosed herein. As shown, the substrate processing system 200 may include a substrate processing tool 210 that may be used to process one or more substrates. The substrate processing tool may be any type of chamber, including, but not limited to, a chemical vapor deposition unit, a physical vapor deposition unit, an etching unit, a chemical mechanical polishing unit, a photolithography unit, or a metrology unit, among others. In the illustrated embodiment, the substrate processing tool 210 includes a vacuum chamber 212, a substrate support 214 configured to hold a substrate 216 (e.g., one of substrates 100a, 100b, or 100c) during substrate processing operations, and a chamber door 218 that allows substrates (including the substrate 216) to be moved into and out of the vacuum chamber 212.

[0019]

[0029] The substrate processing system 200 further includes a substrate transfer mechanism 220 (e.g., a robot) and a substrate storage container 230. The substrate transfer mechanism 220 can transfer substrates between the vacuum chamber 212 and the substrate storage container 230 through a chamber door 218. The substrate storage container can be an enclosure designed to safely and securely hold substrates (e.g., wafers) in a controlled environment and allow the substrates to be transferred between different tools by the substrate transfer mechanism 220 for processing or measurement. In some embodiments, the substrate storage container 230 can be a front-opening unified pod (FOUP) designed according to a common protocol for feeding substrates between different tools within a manufacturing facility.

[0020]

[0030] 2, the substrate processing system 200 may include one or more controllers, processors, or other hardware units 240 that control the operation of the system 200 (including both the processing tools 210 and the substrate transfer mechanism 220) by executing computer instructions stored in one or more computer-readable memories 250, as known to those skilled in the art. By way of example, the computer-readable memories may include solid-state memory (such as random access memory (RAM) and / or read-only memory (ROM), programmable, flash-updateable, and / or the like), disk drives, optical storage devices, or similar non-transitory computer-readable storage media.

[0021]

[0031] Additionally, a user interface 260 may be provided to allow one or more users (e.g., personnel within a semiconductor manufacturing facility) to control various aspects of the substrate processing system 200, including specifying the thickness of the substrates being transferred from the substrate storage container 230 into the substrate processing tool 210, thereby enabling appropriate configuration of various aspects of the substrate processing tool 210. The various components and / or aspects of the tool 210 that may be configured or altered based on the thickness of the substrate being processed in the chamber 212 depend on the type and design of the tool 210. For example, in a deposition or etch tool, the position (e.g., height in the z-direction) of the substrate holder 214 and / or a predetermined distance between a gas dispenser or manifold and the substrate holder may be configured according to the thickness of the substrate. As another example, in a focused ion beam (FIB) tool, the position (e.g., height in the z-direction) of the substrate holder 214 and / or a predetermined distance between the tips of the focused ion beam columns may be configured according to the thickness of the substrate.

[0022]

[0032] Conventionally, once the thickness of the substrates in the substrate storage container 230 has been determined, the system 200 can begin processing the substrates in the chamber 212. For example, the system 200 can use the transfer mechanism 220 to transfer a first substrate from the storage container 230 into the chamber 212 and process the first substrate in the chamber 212. Once the processing operation is complete, the transfer mechanism 220 can return the first substrate to the storage container 230 and transfer a new, second substrate into the chamber 212 for processing. This sequence can be repeated until all of the substrates in the storage container 230 have been processed, at which point the storage container can be transferred to another tool and the substrates therein can be subjected to the next processing operation.

[0023] Exemplary Substrate Transfer Mechanism and Substrate Storage Container

[0033] 3A is a simplified diagram of a substrate transfer mechanism 300 and a substrate storage container 330 according to some embodiments. The substrate transfer mechanism 300 may represent the substrate transfer mechanism 220 described above in connection with FIG. 2. The substrate storage container 330 may represent the substrate storage container 230. As shown, the substrate transfer mechanism 300 includes a robot base 310 and an arm 320 attached to the base 310, while the substrate storage container 330 is capable of securely storing a set of substrates 332 (e.g., 25 substrates in some embodiments) in a controlled environment.

[0024]

[0034] 3B, which is a simplified top view of a robotic arm 320 according to some embodiments, the arm 320 may include two opposing fingers 322. The robotic arm 320 further includes an arm sensor that may be positioned at a distal end of the fingers 322. In some embodiments, the arm sensor includes a pair of an emitter 324 and a detector 326. The emitter 324 may be a laser (e.g., an edge-emitting laser (EEL) or a vertical cavity surface-emitting laser (VCSEL)) positioned at the tip of one of the fingers 322. The detector 326 may be a photodetector positioned at the tip of the opposing finger 322, such that the detector 326 is spaced and aligned from the emitter 324 in an opposing relationship that enables the detector 326 to detect radiation 328 (e.g., a laser beam) emitted from the emitter 324.

[0025]

[0035] In operation, the robot arm 320 can extend toward and enter the substrate storage container 330, retrieve individual substrates from the storage container, and transfer the retrieved substrates into a substrate processing tool (e.g., into the substrate processing chamber 212). The arm 320 can then pick up the substrates from within the chamber 212 and return them to the storage container 330 once processing is complete.

[0026]

[0036] In addition to extending outward into the substrate storage container 330, the arm 320 can move up and down in the z-direction (represented by arrow 340) to select any of the stacked substrates within the container 330. In normal operation, the substrate transfer mechanism 300 can use signals generated from the detector 326 to appropriately position itself vertically relative to an individual substrate 332(i) within the substrate stack 332 being transferred. For example, as shown in FIG. 4 , the arm 320 can extend outward toward one of the substrates in the stack 332 such that the outer periphery of the substrate is located within the gap between two opposing fingers 324, yet is positioned below (or above) the substrate 332(i). The arm 320 can then raise (or lower) relative to the substrate 332(i) until the substrate 332(i) intercepts the radiation beam 328. This indicates the vertical position of the substrate 332(i) relative to the substrate transfer mechanism 300.

[0027] Substrate thickness detection

[0037] In embodiments disclosed herein, the emitter / detector functionality of the substrate transfer mechanism 300 is used to measure the thickness of individual substrates to ensure that substrates transferred into a processing chamber serviced by the substrate transfer mechanism 300 have a thickness that the processing chamber is designed to accept. Reference is now made to FIGS. 5 and 6A-6D. FIG. 5 is a flowchart illustrating steps associated with a method 500 according to some embodiments disclosed herein, and FIGS. 6A-6D are simplified schematic diagrams illustrating the positional relationship between the substrate transfer mechanism and a substrate during various steps of the method 500. Each of FIGS. 6A-6D includes juxtaposed front and top views of a substrate 610 being loaded into a processing chamber. For ease of illustration, FIGS. 6A-6D show only a portion of the substrate transfer mechanism, including the substrate 610, laser 622, photodetector 624, and laser beam 626. The laser beam 626 is emitted from the laser 622 and can be detected by the photodetector 624 if the beam is not blocked, for example, by a portion of the substrate 610. Laser 622 and photodetector 624 may represent emitter 324 and photodetector 326, respectively.

[0028]

[0038] The method 500 may begin by moving a substrate storage container (e.g., container 230) to a position such that the substrates therein (including substrate 610) can be loaded into a substrate processing system (e.g., system 200) and updating the substrate processing system with information indicating the thickness of the substrates stored in the substrate storage container (block 510). The substrate thickness information may be input in any suitable manner. For example, in some embodiments, the information may be input by a user (e.g., an operator in a semiconductor manufacturing system) via user interface 260. One or more components of the processing tool (e.g., substrate processing tool 210) may then be set or adjusted to configure the tool to process substrates having the expected thickness, as described above (block 520). For example, in a deposition or etch tool, the position (e.g., height in the z-direction) of the substrate holder 214 and / or a predetermined distance between a gas dispenser or manifold and the substrate holder may be set according to the thickness of the substrate. As another example, in a focused ion beam (FIB) tool or a scanning electron microscope (SEM) tool, the position of the substrate holder 214 (e.g., height in the z-direction) and / or the predetermined distance between the tips of the focused ion beam column or scanning electron microscope column may be set according to the thickness of the substrate.

[0029]

[0039] Next, the substrate transfer mechanism 300 can begin a mapping process (block 530). In the mapping process, the system maps and records (e.g., in memory 250) the quantity of substrates and the location of each substrate (e.g., slot number within a FOUP) before transferring any substrates into a substrate processing chamber. The mapping process can begin by extending the robot arm 320 toward and slightly into the substrate storage container so that the arm is below the bottom substrate and the perimeter of each substrate in the substrate stack is located directly above the gap between two opposing fingers 324, as described above with respect to FIG. 4 (block 532). As a non-limiting example, in some embodiments, the mapping process can be performed with the robot arm positioned so that the laser beam 626 is 6 mm past the edge of the substrate. During the mapping process, the laser 622 can project the laser beam 626 toward the photodetector 624, and the robot arm scans upward so that the laser beam passes over the perimeter of each individual substrate in the substrate storage container (block 534).

[0030]

[0040] As the robot arm scans upward at a constant speed (block 534), the laser beam is intermittently blocked by individual substrates within the container. To illustrate the processing of individual substrates 610, reference is made to FIGS. 6A-6D. As shown in FIG. 6A, when laser beam 626 is below substrate 610, the beam is not blocked by the substrate and is therefore detected by photodetector 624. (Note that the right-hand portion of FIG. 6A shows by a dashed line the portion of laser beam 626 passing below substrate 610 at this position.) As the robot arm scans upward, laser beam 626 contacts the bottom edge of substrate 610 (indicated by an asterisk in FIG. 6B). Blocking laser beam 626 prevents photodetector 624 from detecting the laser beam, and the point of blockage can be recorded (and saved in computer memory) as the bottom edge of substrate 610. Blockage of laser beam 626 continues as the robot arm moves further upward (FIG. 6C) until it passes the top edge of substrate 610. At this point (represented in FIG. 6D), the laser beam 626 is no longer blocked by the substrate 610 and may again be detected by the photodetector 624. The new detection of the laser beam 626 may then be recorded (and stored in computer memory) as the upper edge of the substrate 610 (block 536). In some embodiments, the edge detection process may be repeated for each and every substrate in the substrate storage container.

[0031]

[0041] Once both the lower and upper edges of the substrate 610 have been detected, the thickness of the substrate 610 can be easily calculated (block 540). For example, if the substrate transfer mechanism records the absolute z-height position or the relative z-height position of the robot arm, the thickness of the substrate 610 can be determined by the difference between the z-height position recorded at the lower substrate edge and the z-height position recorded at the upper substrate edge. As another example, if the detection of the lower and upper edges of the substrate 610 are recorded in memory as units of time, the thickness of the substrate 610 can be calculated based on the time difference between the two detection events multiplied by the z-velocity of the robot arm.

[0032]

[0042] The substrate processing system may then compare the calculated substrate thickness from block 540 with the input / expected substrate thickness from block 510 (block 550). If the two match, the substrate 610 may be transferred into the substrate processing chamber and subjected to any substrate processing operations the chamber is equipped to perform (block 560). To transfer the substrate, in some embodiments, the robot arm may lower to just below the substrate, extend further into the substrate container, and then move slightly upward so that the substrate rests on the top surface of the robot arm (including the top surfaces of the fingers 322).

[0033]

[0043] A match can be determined based on any suitable criteria. For example, in some embodiments, a match can be determined based on whether the calculated thickness is within a predetermined percentage (e.g., within 5%, 10%, or 20%) of the expected thickness. As another example, in some embodiments, thicknesses can be calculated for sample substrates of various thicknesses according to blocks 550 and 560, and although this calculated thickness may differ from the actual substrate thickness, it can be reconciled with the actual substrate thickness and stored in a lookup table or similar data structure. Then, once a thickness measurement for a processed substrate is calculated according to method 500, the calculated thickness can be compared to the lookup table and correlated with the expected thickness to determine a match. The lookup table can be referenced based on ranges stored in the table, and average or median values ​​can be stored in the table, with the correlation based on the calculated thickness being within a predetermined percentage of the recorded average or median value.

[0034]

[0044] However, if the calculated substrate thickness does not match the input / expected substrate thickness, a "Substrate Thickness Mismatch" alert may be generated (block 570) and appropriate corrective action may be taken (block 580). Corrective action may include appropriate measures to remedy the substrate thickness mismatch. By way of non-limiting example, such actions may include one or more of: sending an alert to a tool operator (e.g., a worker in a manufacturing facility) so that the operator can take corrective action; automatically changing or otherwise modifying the tool settings to adjust one or more components so that the chamber is configured to handle substrates having the calculated thickness rather than the originally expected thickness; or preventing transfer of the substrate 610 to the processing chamber and replacing the substrate storage container with a new substrate storage container containing substrates having the expected thickness.

[0035]

[0045] In some embodiments, once appropriate corrective action has been taken, the substrate is ready to be transferred to a processing chamber, as indicated by the dashed line from block 580 to block 560. As described above, method 500 can be performed as part of an initial mapping process in which the system maps and records (e.g., in memory 250) the number of substrates and the location of each substrate (e.g., slot number within a FOUP) before transferring any substrates into a substrate processing chamber. Such a mapping process can be performed each time a new substrate storage container is transferred to the system. In other embodiments, method 500 can be performed individually for each substrate in a given substrate storage container, either separately from or in place of the described mapping process.

[0036]

[0046] While method 500 includes an initial step in which a user inputs information regarding the expected substrate thickness into the substrate processing system, in some embodiments, such a preliminary step is not required. For example, FIG. 7 is a flowchart illustrating steps associated with method 700 according to some embodiments. Method 700 includes many of the same steps as method 500, but for the sake of brevity, a description of such steps will not be repeated. However, method 700 differs from method 500 in that method 700 is fully automated in the substrate processing system; once the substrate thickness is calculated (block 540), the substrate processing chamber is automatically adjusted to process a substrate of the calculated thickness (block 710).

[0037] Exemplary Sample Evaluation System

[0047] While the embodiments disclosed herein can be beneficially used with many different types of substrate processing chambers, one specific type of processing chamber that can be utilized in embodiments is a substrate evaluation system. The substrate evaluation system can be used, among other things, for milling and imaging semiconductor wafers and depositing various materials onto substrates using particle-enhanced deposition processes. FIG. 8 is a simplified schematic diagram of such a substrate evaluation system 800. The substrate processing system 800 can include a vacuum chamber 810 along with a focused ion beam (FIB) column 820 and a scanning electron microscope (SEM) column 830. A support element 840 can support a sample 850 (e.g., a semiconductor wafer) within the chamber 810 during processing operations. During the processing operations, the sample 850 (which may be referred to herein as an “object” or “specimen”) is subjected to a charged particle beam from one of the FIB or SEM columns 820, 830, and the sample can be moved within the vacuum chamber 810 between the fields of view of the two columns 820 and 830, depending on the processing needs.

[0038]

[0048] During processing operations, one or more gases can be supplied into chamber 810 by gas injection system 860 for a particular operation. For ease of illustration, gas injection system 860 is depicted in FIG. 8 as a nozzle; however, it should be noted that gas injection system 860 may include, among other things, a gas reservoir, a gas source, a valve, one or more inlets, and one or more outlets. In some embodiments, as opposed to supplying gas to the entire top surface of the sample, gas injection system 860 may be configured to supply gas to a localized region of sample 850 exposed to the scan pattern of the charged particle beam. For example, in some embodiments, gas injection system 860 has a nozzle diameter measuring several hundred microns (e.g., between 400 and 500 microns) configured to supply gas directly to a relatively small portion of the sample surface encompassing the charged particle beam scan pattern. In various embodiments, the first gas injection system 860 may be configured to supply gas to a sample positioned below the FIB column 820, and the second gas injection system 860 may be configured to supply gas to a sample positioned below the SEM column 830.

[0039]

[0049] The FIB column 820 and the SEM column 830 are connected to a vacuum chamber 810 such that a charged particle beam generated by either of the charged particle columns propagates through a vacuum environment created within the vacuum chamber 810 before striking the sample 850. For example, as shown in FIG. 8 , the FIB column 820 can generate a focused ion beam 825 that travels through the vacuum environment of the chamber 810 before striking the sample 850.

[0040]

[0050] The FIB column 820 can mill (e.g., drill) the sample 850 to form a cross section and can also smooth the cross section by irradiating the sample with one or more charged particle beams. The cross section can include one or more first portions of a first material and one or more second portions of a second material. The cross section can further include additional portions of other materials. Conveniently, the smoothing operation involves the use of a lower acceleration voltage relative to milling the sample. The SEM column 830 can generate an image of a portion of the sample 850 by irradiating the sample with a charged particle beam, detecting particles emitted by the irradiation (e.g., using a suitable detector not shown in FIG. 8 ), and generating a charged particle image based on the detected particles.

[0041]

[0051] Particle imaging and milling processes typically involve scanning a charged particle beam back and forth at a constant velocity (e.g., in a raster scan pattern) over a specific area of ​​the sample to be imaged or milled, respectively. One or more lenses (not shown) coupled to the charged particle column can perform the scan pattern, as known to those skilled in the art. The scanned area is typically a small portion of the overall area of ​​the sample. For example, the sample may be a semiconductor wafer, either 200 mm or 300 mm in diameter, but each scanned area on the wafer may be a rectangular area with width and / or length measured in microns or tens of microns.

[0042]

[0052] 8, system 800 may include one or more controllers, processors, or other hardware units 870 that control the operation of system 800 by executing computer instructions stored in one or more computer-readable memories 880 as known to those skilled in the art. By way of example, the computer-readable memories may include solid-state memory (such as random access memory (RAM) and / or read-only memory (ROM), programmable, flash-updateable, and / or the like), disk drives, optical storage devices, or similar non-transitory computer-readable storage media.

[0043] Examples of samples to be transferred

[0053] As noted above, embodiments of the present disclosure can be used in conjunction with the processing of many types of samples or substrates, although some embodiments are particularly useful in measuring the thickness of wafers used in the manufacture of semiconductor devices (including wafers, gallium arsenide wafers, etc.). As a non-limiting example, FIG. 9 is a simplified diagram of an area on a semiconductor wafer that may be transferred to a substrate processing chamber, such as chamber 800 described above, according to some embodiments. Specifically, FIG. 9 includes a top view of wafer 900 and two enlarged views of specific portions of wafer 900. Wafer 900 may be, for example, a 150 mm, 200 mm, or 300 mm semiconductor wafer and may include multiple integrated circuits 910 (52 in the illustrated example) formed thereon. The integrated circuits 910 may be in an intermediate stage of fabrication. Once substrate 900 has been transferred into the chamber according to one of methods 500 or 700 described above, chamber 800 may be used to evaluate and analyze one or more areas 920 of the integrated circuit.

[0044] Additional Embodiments

[0054] In the foregoing description, for purposes of explanation, specific terminology is used to facilitate a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that specific details are not required to practice the described embodiments. Accordingly, the foregoing description of specific embodiments described herein has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. For example, although methods 500 and 700 are described above as detecting the edge of a substrate as the robot arm moves from a position below the substrate to above the substrate, in some embodiments, the detection process may be reversed as the robot arm moves from above the substrate to below the substrate. Furthermore, in other embodiments, the upper and lower edges of the substrate may be detected using other techniques (e.g., techniques using a camera or other imaging device positioned a known distance from the substrate).

[0045]

[0055] Furthermore, while various embodiments of the present disclosure have been disclosed above, the specific details of particular embodiments can be combined in any suitable manner without departing from the spirit and scope of the embodiments of the present disclosure. Moreover, many modifications and variations will be apparent to those skilled in the art in light of the above teachings. It is therefore to be understood that the appended claims are intended to cover all modifications and variations that fall within the true spirit of the embodiments of the present disclosure.

[0046]

[0056] Furthermore, references in the specification to a method should apply mutatis mutandis to a system capable of carrying out the method, and should apply mutatis mutandis to a computer program product storing instructions that, when executed, result in the performance of the method. Similarly, references in the specification to a system should apply mutatis mutandis to a method that may be performed by the system, and should apply mutatis mutandis to a computer program product storing instructions that may be executed by the system. Also, references in the specification to a computer program product should apply mutatis mutandis to a method that may be performed when executing instructions stored in the computer program product, and should apply mutatis mutandis to a system configured to execute instructions stored in the computer program product.

[0047]

[0057] Furthermore, to the extent that the illustrated embodiments of the present disclosure can, for the most part, be implemented using electronic components and circuits known to those skilled in the art, details of such will not be described beyond the extent deemed necessary, as exemplified above, for an understanding and appreciation of the concepts underlying the present disclosure and so as not to obscure or distract from the teachings of the present disclosure.

Claims

1. 1. A method of operating a substrate processing system, the substrate processing system including a substrate processing chamber, a substrate storage container, and a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber, the method comprising: Detecting a lower edge and an upper edge of the substrate; calculating a thickness of the substrate based on the detected lower and upper edges of the substrate; comparing the calculated thickness of the substrate to an expected thickness of the substrate; (i) if the calculated thickness matches the expected thickness, controlling the robot to transfer the substrate into the substrate processing chamber; (ii) if the calculated thickness does not match the expected thickness, generating an alert indicating a thickness discrepancy; 10. A method of operating a substrate processing system, comprising:

2. 10. The method of operating a substrate processing system of claim 1, wherein detecting the lower and upper edges of the substrate occurs during a substrate mapping process in which the quantity of substrates and the position of each substrate within the substrate storage container are mapped and recorded.

3. The method of operating a substrate processing system of claim 2 , wherein the substrate storage container is a Front Opening Unified Pod (FOUP).

4. 10. The method of operating a substrate processing system of claim 1, wherein the robot includes a robot arm having sensors configured to detect the lower edge and the upper edge of the substrate.

5. 5. The method of operating a substrate processing system of claim 4, wherein the robot arm comprises a first finger and a second finger spaced apart from each other in an opposing relationship, the sensor comprises a laser and a photodetector, the laser being positioned near a distal end of the first finger and the photodetector being positioned near a distal end of the second finger and aligned with the laser so as to detect a laser beam emitted from the laser.

6. 6. The method of operating a substrate processing system of claim 5, wherein detecting the lower and upper edges of the substrate is performed when the robot arm scans vertically across the substrate storage container and the robot arm is positioned such that the outer periphery of the substrate passes between the first and second fingers and interferes with the laser beam during a scanning process.

7. 10. The method of operating a substrate processing system of claim 1, wherein the system comprises a controller operably coupled to control functions of the substrate processing system, and a computer readable memory coupled to the controller, the method further comprising inputting an expected substrate thickness into the computer readable memory via a user interface prior to detecting the lower edge and the upper edge of the substrate.

8. 8. The method of operating a substrate processing system according to claim 1, further comprising setting or adjusting one or more components of the substrate processing chamber based on the expected thickness of the substrate before detecting the lower and upper ends of the substrate.

9. 10. The method of operating a substrate processing system of claim 8, further comprising preventing the substrate from being transferred into the substrate processing chamber if the calculated thickness does not match the expected thickness.

10. 10. The method of operating a substrate processing system of claim 8, further comprising: setting or adjusting one or more components of the substrate processing chamber based on the calculated thickness if the calculated thickness does not match the expected thickness.

11. 10. The method of operating a substrate processing system of claim 1, wherein the substrate processing chamber is capable of being used for defect review, classification, and analysis, and the substrate processing chamber includes a focused ion beam (FIB) column and a scanning electron microscope (SEM) column.

12. The method of operating a substrate processing system of claim 1 , wherein the substrate is a semiconductor wafer.

13. 1. A substrate processing system, comprising: a substrate processing chamber; Substrate storage container, a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber; and a processor and a memory coupled to the processor the memory including a plurality of computer readable instructions that, when executed by the processor, cause the system to: Detecting a lower edge and an upper edge of the substrate; calculating a thickness of the substrate based on the detected lower and upper edges of the substrate; comparing the calculated thickness of the substrate to an expected thickness of the substrate; and (i) controlling the robot to transfer the substrate into a substrate processing chamber if the calculated thickness matches the expected thickness; and (ii) generating an alert indicating a thickness discrepancy if the calculated thickness does not match the expected thickness. A substrate processing system that performs the above.

14. 14. The substrate processing system of claim 13, wherein the lower edge and the upper edge of the substrate are detected during a substrate mapping process in which the quantity of substrates and the position of each substrate within the substrate storage container are mapped and recorded.

15. 15. The substrate processing system of claim 13 or 14, wherein the robot arm comprises a first finger and a second finger spaced apart from each other in an opposing relationship, and a sensor comprising a laser and a photodetector, the laser being positioned near a distal end of the first finger, and the photodetector being positioned near a distal end of the second finger and aligned with the laser so as to detect a laser beam emitted from the laser.

16. 16. The substrate processing system of claim 15, wherein the lower and upper edges of the substrate are detected when the robot arm scans vertically across the substrate storage container and the robot arm is positioned such that an outer periphery of the substrate passes between the first and second fingers to interfere with the laser beam during a scanning process.

17. 1. A non-transitory computer readable memory storing computer readable instructions for operating a substrate processing system, the substrate processing system including a substrate processing chamber, a substrate storage container, and a robot configured to select a substrate from the substrate storage container and transfer the selected substrate into the substrate processing chamber, the computer readable instructions, when executed by a processor operably coupled to the substrate processing chamber, causing the processor to control the substrate processing system to: Detecting a lower edge and an upper edge of the substrate; calculating a thickness of the substrate based on the detected lower and upper edges of the substrate; comparing the calculated thickness of the substrate to an expected thickness of the substrate; and (i) controlling the robot to transfer the substrate into the substrate processing chamber if the calculated thickness matches the expected thickness; and (ii) generating an alert indicating a thickness discrepancy if the calculated thickness does not match the expected thickness. a non-transitory computer-readable memory that performs

18. 20. The non-transitory computer-readable memory of claim 17, wherein the lower and upper edges of the substrate are detected during a substrate mapping process in which the quantity of substrates and the position of each substrate within the substrate storage container are mapped and recorded.

19. 19. The non-transitory computer-readable memory of claim 17 or 18, wherein the robot includes a robot arm having a first finger and a second finger spaced apart from each other in opposing relationship, and a sensor having a laser and a photodetector, the laser being positioned near a distal end of the first finger and the photodetector being positioned near a distal end of the second finger and aligned with the laser so as to detect a laser beam emitted from the laser.

20. 20. The non-transitory computer readable memory of claim 19, wherein the lower edge and the upper edge of the substrate are detected when the robot arm scans vertically across the substrate storage container and the robot arm is positioned such that an outer periphery of the substrate passes between the first finger and the second finger to interfere with the laser beam during a scanning process.

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