SYSTEMS AND METHODS FOR COOLING IN TESTING SYSTEMS

Abstract

Cooling systems and methods for charge carrier systems. These systems and methods may include a cooling pad attached to a vacuum chamber, a cooling pad configured to hold and cool multiple modules; and a controller configured to monitor the temperature of the cooling pad; monitor the temperature of the vacuum chamber or the ambient temperature; and adjust the temperature of the cooling pad based on the temperature of the cooling pad, the temperature of the vacuum chamber, or the ambient temperature. The system may include a heat transfer device between the base plate of the plate and the inner surface of the vacuum chamber, a heat transfer device comprising deformable parts to be deformed by the base plate or the inner surface of the vacuum chamber; and a cooling pad outside the vacuum chamber opposite the base plate.

Description

SYSTEMS AND METHODS FOR COOLING IN INSPECTION SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of US application 63 / 592,540 which was filed on October 23, 2023 and which is incorporated herein in its entirety by reference.FIELD

[0002] The description herein relates to the field of inspection and charged particle systems, and more particularly to systems for cooling in inspection systems.BACKGROUND

[0003] In manufacturing processes of integrated circuits (ICs), unfinished or finished circuit components are inspected to ensure that they are manufactured according to design and are free of defects. An inspection system utilizing an optical microscope typically has resolution down to a few hundred nanometers; and the resolution is limited by the wavelength of light. As the physical sizes of IC components continue to reduce down to sub- 100 or even sub- 10 nanometers, inspection systems capable of higher resolution than those utilizing optical microscopes are needed.

[0004] A charged particle (e.g., electron) beam microscope, such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM), capable of resolution down to less than a nanometer, serves as a practicable tool for inspecting IC components having a feature size that is sub- 100 nanometers. With a SEM, electrons of a single primary electron beam, or electrons of a plurality of primary electron beams, can be focused on locations of interest of a wafer under inspection. The primary electrons interact with the wafer and may be backscattered or may cause the wafer to emit secondary electrons. The intensity of the electron beams comprising the backscattered electrons and the secondary electrons may vary based on the properties of the internal and external structures of the wafer, and thereby may indicate whether the wafer has defects.SUMMARY

[0005] Embodiments of the present disclosure provide systems and methods for cooling in a charged particle system. In some embodiments, systems, methods, and non-transitory computer readable mediums may include a wafer stage for holding a wafer in a vacuum chamber; a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold and cool a plurality of modules; and a controller having one or more processors and configured to: monitor a temperature of the cooling platform; monitor a temperature of the vacuum chamber or a temperature of an ambient environment; and adjust the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.

[0006] In some embodiments, systems, methods, and non-transitory computer readable mediums may include a wafer stage for holding a wafer in a vacuum chamber; a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold a plurality of modules and to transfer heat from the plurality of modules to the cooling platform; and a controller configured to adjust heat transfer from the plurality of modules to the cooling platform by adjusting a temperature of the cooling platform based on the temperature of the cooling platform, a temperature of the vacuum chamber, or a temperature of the ambient environment.

[0007] In some embodiments, systems may include a wafer stage for holding a wafer in a vacuum chamber, the wafer stage comprising: a base plate; a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber; and a cooling platform on an outside surface of the vacuum chamber directly opposite to the base plate.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. 1 is a schematic diagram illustrating an exemplary electron beam inspection (EBI) system, consistent with embodiments of the present disclosure.

[0009] Fig. 2A is a schematic diagram illustrating an exemplary multi-beam system that is part of the exemplary charged particle beam inspection system of Fig. 1, consistent with embodiments of the present disclosure.

[0010] Fig. 2B is a schematic diagram illustrating an exemplary single -beam system that is part of the exemplary charged particle beam inspection system of Fig. 1, consistent with embodiments of the present disclosure.

[0011] Fig. 3 shows an exemplary charged particle system.

[0012] Fig. 4 shows an exemplary charged particle system, consistent with embodiments of the present disclosure.

[0013] Fig. 5 shows a top view of the charged particle system of Fig. 4, consistent with embodiments of the present disclosure.

[0014] Fig. 6 shows an exemplary charged particle system.

[0015] Fig. 7 shows an exemplary charged particle system, consistent with embodiments of the present disclosure.

[0016] Fig. 8 shows an exemplary process for cooling in a charged particle system, consistent with embodiments of the present disclosure.DETAILED DESCRIPTION

[0017] Reference will now be made in detail to exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings in which the same numbers in different drawings represent the same or similar elementsunless otherwise represented. The implementations set forth in the following description of exemplary embodiments do not represent all implementations consistent with the disclosure. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the subject matter recited in the appended claims. For example, although some embodiments are described in the context of utilizing electron beams, the disclosure is not so limited. Other types of charged particle beams may be similarly applied. Furthermore, other imaging systems may be used, such as optical imaging, photodetection, x-ray detection, extreme ultraviolet inspection, deep ultraviolet inspection, or the like, in which they generate corresponding types of images.

[0018] Electronic devices are constructed of circuits formed on a piece of silicon called a substrate. Many circuits may be formed together on the same piece of silicon and are called integrated circuits or ICs. The size of these circuits has decreased dramatically so that many more of them can fit on the substrate. For example, an IC chip in a smart phone can be as small as a thumbnail and yet may include over 2 billion transistors, the size of each transistor being less than 1 / 1000th the size of a human hair.

[0019] Making these extremely small ICs is a complex, time-consuming, and expensive process, often involving hundreds of individual steps. Errors in even one step have the potential to result in defects in the finished IC rendering it useless. Thus, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs made in the process, that is, to improve the overall yield of the process.

[0020] One component of improving yield is monitoring the chip making process to ensure that it is producing a sufficient number of functional ICs. One way to monitor the process is to inspect the chip circuit structures at various stages of their formation. Inspection may be carried out using a scanning charged particle microscope (SCPM), such as a scanning electron microscope (SEM). A SEM can be used to image these extremely small structures, in effect, taking a “picture” of the structures of the wafer. The image can be used to determine if the structure was formed properly, and also if it was formed at the proper location. If the structure is defective, then the process can be adjusted so the defect is less likely to recur. Defects may be generated during various stages of semiconductor processing. For the reason stated above, it is important to find defects accurately and efficiently as early as possible.

[0021] The working principle of a SEM is similar to a camera. A camera takes a picture by receiving and recording brightness and colors of light reflected or emitted from people or objects. A SEM takes a “picture” by receiving and recording energies or quantities of electrons reflected or emitted from the structures. Before taking such a “picture,” an electron beam may be projected onto the structures, and when the electrons are reflected or emitted (“exiting”) from the structures, a detector of the SEM may receive and record the energies or quantities of those electrons to generate an image. To take such a “picture,” some SEMs use a single electron beam (referred to as a “single-beam SEM”), while some SEMs use multiple electron beams (referred to as a “multi-beam SEM”) to take multiple “pictures” ofthe wafer. By using multiple electron beams, the SEM may project more electron beams onto the structures for obtaining these multiple “pictures,” resulting in more electrons exiting from the structures. Accordingly, the detector may receive more exiting electrons simultaneously, and generate images of the structures of the wafer with a higher efficiency and a faster speed.

[0022] Existing charged particle systems do not have an active cooling solution for the chamber of the system. Modules on top of the chamber (e.g., e-modules) in existing systems are cooled by natural convection (e.g., exposed to an ambient environment). In existing systems, some critical components (e.g., the SEM and the wafer stage) are sometimes cooled by water cooling. Wafer stage water cooling requires sending cooling fluid into the main chamber in a deep vacuum environment.

[0023] In typical systems (see, e.g., Fig. 3), the temperature of the chamber body is noticeably raised due to heat transferring from on-chamber modules to the chamber body. Typical systems suffer from constraints. For example, the higher temperature of the main chamber negatively affects system performance by impeding heat dissipation for modules directly connected to the main chamber. For example, the higher temperature of the main chamber results in overheating the modules and the main chamber, thereby negatively affecting high-precision metrology devices connected to the main chamber and reducing control accuracy of the wafer stage. The higher temperature of the main chamber causes thermal expansion of the wafer and associated throughput loss of image shift, as well as tribological particle generation and contamination on the backside of the wafer.

[0024] Typical systems may use individual water cooling to cool components such as the SEM and the wafer stage, which requires complex cooling loop designs with high volume and monetary investment. Additionally, for optimal module-level water cooling efficiency, cooling fluid is delivered near the sources of heat, which are usually in the main chamber in a deep vacuum environment. However, water cooling in a deep vacuum environment is disadvantageous with a high risk of outgassing and catastrophic consequences if leakage of the cooling loop occurs in the sensitive vacuum environment of the main chamber.

[0025] Typical systems (e.g., Fig. 6) suffer from additional constraints. For example, heat transfer efficiency between the wafer stage and the main chamber is minimal, due at least in part to the minimal contact area between the wafer stage and the bottom surface of the main chamber. This minimal contact area may lead to heat accumulation and thermal drifting of sensitive modules. As discussed above, water cooling also suffers from constraints (e.g., leakage, etc.). Moreover, increasing the contact area between the wafer stage and the main chamber would increase the difficulty in leveling the wafer stage.

[0026] The disclosed embodiments provide systems and methods that address some or all of these disadvantages by providing water cooling armor (WCA) (e.g., a cooling platform) mounted to the vacuum chamber of a charged particle system. The WCA may hold and cool modules on the vacuum chamber by monitoring a temperature of the WCA, monitoring a temperature of the vacuum chamber or a temperature of an ambient environment, and adjusting the temperature of the WCA based on thetemperature of the WCA, the temperature of the vacuum chamber, or the temperature of the ambient environment.

[0027] Advantageously, the WCA of the present disclosure may prevent overheating, thermal shift of high-precision metrology devices connected to the main chamber, thermal drift and loss of control accuracy of the wafer stage, thermal expansion of the wafer, and contamination on the backside of the wafer. Moreover, outgassing and leakage may be avoided since individual water cooling is not needed.

[0028] Some embodiments of the present disclosure may also include a heat transfer facilitator with deformation components to achieve the high precision requirements of the wafer stage. For example, when the wafer stage is installed, its height may be adjusted and calibrated during leveling of the wafer stage. Advantageously, the deformation components may increase heat transfer efficiency between the wafer stage and the main chamber without negatively impacting leveling of the wafer stage.

[0029] Relative dimensions of components in drawings may be exaggerated for clarity. Within the following description of drawings, the same or like reference numbers refer to the same or like components or entities, and only the differences with respect to the individual embodiments are described.

[0030] As used herein, unless specifically stated otherwise, the term “or” encompasses all possible combinations, except where infeasible. For example, if it is stated that a component may include A or B, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or A and B. As a second example, if it is stated that a component may include A, B, or C, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0031] Without limiting the scope of the present disclosure, some embodiments may be described in the context of providing detectors and detection methods in systems utilizing electron beams. However, the disclosure is not so limited. Other types of charged particle beams may be similarly applied. Furthermore, systems and methods for detection may be used in other imaging systems, such as optical imaging, photon detection, x-ray detection, ion detection, etc.

[0032] Fig. 1 illustrates an exemplary electron beam inspection (EBI) system 100 consistent with embodiments of the present disclosure. EBI system 100 may be used for imaging. As shown in Fig. 1, EBI system 100 includes a main chamber 101, a load / lock chamber 102, an electron beam tool 104, and an equipment front end module (EFEM) 106. Electron beam tool 104 is located within main chamber 101. EFEM 106 includes a first loading port 106a and a second loading port 106b. EFEM 106 may include additional loading port(s). First loading port 106a and second loading port 106b receive wafer front opening unified pods (FOUPs) that contain wafers (e.g., semiconductor wafers or wafers made of other material(s)) or samples to be inspected (wafers and samples may be used interchangeably). A “lot” is a plurality of wafers that may be loaded for processing as a batch.

[0033] One or more robotic arms (not shown) in EFEM 106 may transport the wafers to load / lock chamber 102. Load / lock chamber 102 is connected to a load / lock vacuum pump system (not shown) which removes gas molecules in load / lock chamber 102 to reach a first pressure below the atmospheric pressure. After reaching the first pressure, one or more robotic arms (not shown) may transport the wafer from load / lock chamber 102 to main chamber 101. Main chamber 101 is connected to a main chamber vacuum pump system (not shown) which removes gas molecules in main chamber 101 to reach a second pressure below the first pressure. After reaching the second pressure, the wafer is subject to inspection by electron beam tool 104. Electron beam tool 104 may be a single-beam system or a multi-beam system.

[0034] A controller 109 is electronically connected to electron beam tool 104. Controller 109 may be a computer configured to execute various controls of EBI system 100. While controller 109 is shown in Fig. 1 as being outside of the structure that includes main chamber 101, load / lock chamber 102, and EFEM 106, it is appreciated that controller 109 may be a part of the structure.

[0035] In some embodiments, controller 109 may include one or more processors (not shown). A processor may be a generic or specific electronic device capable of manipulating or processing information. For example, the processor may include any combination of any number of a central processing unit (or “CPU”), a graphics processing unit (or “GPU”), an optical processor, a programmable logic controllers, a microcontroller, a microprocessor, a digital signal processor, an intellectual property (IP) core, a Programmable Logic Array (PLA), a Programmable Array Logic (PAL), a Generic Array Logic (GAL), a Complex Programmable Logic Device (CPLD), a Field- Programmable Gate Array (FPGA), a System On Chip (SoC), an Application-Specific Integrated Circuit (ASIC), and any type circuit capable of data processing. The processor may also be a virtual processor that includes one or more processors distributed across multiple machines or devices coupled via a network.

[0036] In some embodiments, controller 109 may further include one or more memories (not shown). A memory may be a generic or specific electronic device capable of storing codes and data accessible by the processor (e.g., via a bus). For example, the memory may include any combination of any number of a random-access memory (RAM), a read-only memory (ROM), an optical disc, a magnetic disk, a hard drive, a solid-state drive, a flash drive, a security digital (SD) card, a memory stick, a compact flash (CF) card, or any type of storage device. The codes may include an operating system (OS) and one or more application programs (or “apps”) for specific tasks. The memory may also be a virtual memory that includes one or more memories distributed across multiple machines or devices coupled via a network.

[0037] Embodiments of this disclosure may provide a single charged-particle beam imaging system (“single -beam system”). Compared with a single-beam system, a multiple charged-particle beam imaging system (“multi-beam system”) may be designed to optimize throughput for different scan modes. Embodiments of this disclosure provide a multi-beam system with the capability of optimizingthroughput for different scan modes by using beam arrays with different geometries and adapting to different throughputs and resolution requirements.

[0038] Reference is now made to Fig. 2A, which is a schematic diagram illustrating an exemplary electron beam tool 104 including a multi-beam inspection tool that is part of the EBI system 100 of Fig. 1, consistent with embodiments of the present disclosure. In some embodiments, electron beam tool 104 may be operated as a single-beam inspection tool that is part of EBI system 100 of Fig. 1. Multi-beam electron beam tool 104 (also referred to herein as apparatus 104) comprises an electron source 201, a Coulomb aperture plate (or “gun aperture plate”) 271, a condenser lens 210, a source conversion unit 220, a primary projection system 230, a motorized stage 209, and a sample holder 207 supported by motorized stage 209 to hold a sample 208 (e.g., a wafer or a photomask) to be inspected. Multi-beam electron beam tool 104 may further comprise a secondary projection system 250 and an electron detection device 240. Primary projection system 230 may comprise an objective lens 231. Electron detection device 240 may comprise a plurality of detection elements 241, 242, and 243. A beam separator 233 and a deflection scanning unit 232 may be positioned inside primary projection system 230.

[0039] Electron source 201, Coulomb aperture plate 271, condenser lens 210, source conversion unit 220, beam separator 233, deflection scanning unit 232, and primary projection system 230 may be aligned with a primary optical axis 204 of apparatus 104. Secondary projection system 250 and electron detection device 240 may be aligned with a secondary optical axis 251 of apparatus 104.

[0040] Electron source 201 may comprise a cathode (not shown) and an extractor or anode (not shown), in which, during operation, electron source 201 is configured to emit primary electrons from the cathode and the primary electrons are extracted or accelerated by the extractor and / or the anode to form a primary electron beam 202 that form a primary beam crossover (virtual or real) 203. Primary electron beam 202 may be visualized as being emitted from primary beam crossover 203.

[0041] Source conversion unit 220 may comprise an image-forming element array (not shown), an aberration compensator array (not shown), a beam-limit aperture array (not shown), and a pre-bending micro-deflector array (not shown). In some embodiments, the pre-bending micro-deflector array deflects a plurality of primary beamlets 211, 212, 213 of primary electron beam 202 to normally enter the beam-limit aperture array, the image-forming element array, and an aberration compensator array. In some embodiments, apparatus 104 may be operated as a single -beam system such that a single primary beamlet is generated. In some embodiments, condenser lens 210 is designed to focus primary electron beam 202 to become a parallel beam and be normally incident onto source conversion unit 220. The image-forming element array may comprise a plurality of micro-deflectors or micro-lenses to influence the plurality of primary beamlets 211, 212, 213 of primary electron beam 202 and to form a plurality of parallel images (virtual or real) of primary beam crossover 203, one for each of the primary beamlets 211, 212, and 213. In some embodiments, the aberration compensator array may comprise a field curvature compensator array (not shown) and an astigmatism compensator array (notshown). The field curvature compensator array may comprise a plurality of micro-lenses to compensate field curvature aberrations of the primary beamlets 211, 212, and 213. The astigmatism compensator array may comprise a plurality of micro-stigmators to compensate astigmatism aberrations of the primary beamlets 211, 212, and 213. The beam-limit aperture array may be configured to limit diameters of individual primary beamlets 211, 212, and 213. Fig. 2A shows three primary beamlets 211, 212, and 213 as an example, and it is appreciated that source conversion unit 220 may be configured to form any number of primary beamlets. Controller 109 may be connected to various parts of EBI system 100 of Fig. 1, such as source conversion unit 220, electron detection device 240, primary projection system 230, or motorized stage 209. In some embodiments, as explained in further details below, controller 109 may perform various image and signal processing functions. Controller 109 may also generate various control signals to govern operations of the charged particle beam inspection system.

[0042] Condenser lens 210 is configured to focus primary electron beam 202. Condenser lens 210 may further be configured to adjust electric currents of primary beamlets 211, 212, and 213 downstream of source conversion unit 220 by varying the focusing power of condenser lens 210. Alternatively, the electric currents may be changed by altering the radial sizes of beam-limit apertures within the beam-limit aperture array corresponding to the individual primary beamlets. The electric currents may be changed by both altering the radial sizes of beam-limit apertures and the focusing power of condenser lens 210. Condenser lens 210 may be an adjustable condenser lens that may be configured so that the position of its first principal plane is movable. The adjustable condenser lens may be configured to be magnetic, which may result in off-axis beamlets 212 and 213 illuminating source conversion unit 220 with rotation angles. The rotation angles change with the focusing power or the position of the first principal plane of the adjustable condenser lens. Condenser lens 210 may be an anti-rotation condenser lens that may be configured to keep the rotation angles unchanged while the focusing power of condenser lens 210 is changed. In some embodiments, condenser lens 210 may be an adjustable anti-rotation condenser lens, in which the rotation angles do not change when its focusing power and the position of its first principal plane are varied.

[0043] Objective lens 231 may be configured to focus beamlets 211, 212, and 213 onto a sample 208 for inspection and may form, in the current embodiments, three probe spots 221, 222, and 223 on the surface of sample 208. Coulomb aperture plate 271, in operation, is configured to block off peripheral electrons of primary electron beam 202 to reduce Coulomb effect. The Coulomb effect may enlarge the size of each of probe spots 221, 222, and 223 of primary beamlets 211, 212, 213, and therefore deteriorate inspection resolution.

[0044] Beam separator 233 may, for example, be a Wien filter comprising an electrostatic deflector generating an electrostatic dipole field and a magnetic dipole field (not shown in Fig. 2A). In operation, beam separator 233 may be configured to exert an electrostatic force by electrostatic dipole field on individual electrons of primary beamlets 211, 212, and 213. The electrostatic force is equal inmagnitude but opposite in direction to the magnetic force exerted by magnetic dipole field of beam separator 233 on the individual electrons. Primary beamlets 211, 212, and 213 may therefore pass at least substantially straight through beam separator 233 with at least substantially zero deflection angles.

[0045] Deflection scanning unit 232, in operation, is configured to deflect primary beamlets 211, 212, and 213 to scan probe spots 221, 222, and 223 across individual scanning areas in a section of the surface of sample 208. In response to incidence of primary beamlets 211, 212, and 213 or probe spots 221, 222, and 223 on sample 208, electrons emerge from sample 208 and generate three secondary electron beams 261, 262, and 263. Each of secondary electron beams 261, 262, and 263 typically comprise secondary electrons (having electron energy < 50eV) and backscattered electrons (having electron energy between 50eV and the landing energy of primary beamlets 211, 212, and 213). Beam separator 233 is configured to deflect secondary electron beams 261, 262, and 263 towards secondary projection system 250. Secondary projection system 250 subsequently focuses secondary electron beams 261, 262, and 263 onto detection elements 241, 242, and 243 of electron detection device 240. Detection elements 241, 242, and 243 are arranged to detect corresponding secondary electron beams 261, 262, and 263 and generate corresponding signals which are sent to controller 109 or a signal processing system (not shown), e.g., to construct images of the corresponding scanned areas of sample 208.

[0046] In some embodiments, detection elements 241, 242, and 243 detect corresponding secondary electron beams 261, 262, and 263, respectively, and generate corresponding intensity signal outputs (not shown) to an image processing system (e.g., controller 109). In some embodiments, each detection element 241, 242, and 243 may comprise one or more pixels. The intensity signal output of a detection element may be a sum of signals generated by all the pixels within the detection element.

[0047] In some embodiments, controller 109 may comprise image processing system that includes an image acquirer (not shown), a storage (not shown). The image acquirer may comprise one or more processors. For example, the image acquirer may comprise a computer, server, mainframe host, terminals, personal computer, any kind of mobile computing devices, and the like, or a combination thereof. The image acquirer may be communicatively coupled to electron detection device 240 of apparatus 104 through a medium such as an electrical conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, wireless radio, among others, or a combination thereof. In some embodiments, the image acquirer may receive a signal from electron detection device 240 and may construct an image. The image acquirer may thus acquire images of sample 208. The image acquirer may also perform various post-processing functions, such as generating contours, superimposing indicators on an acquired image, and the like. The image acquirer may be configured to perform adjustments of brightness and contrast, etc. of acquired images. In some embodiments, the storage may be a storage medium such as a hard disk, flash drive, cloud storage, random access memory (RAM), other types of computer readable memory, and the like. The storage may be coupledwith the image acquirer and may be used for saving scanned raw image data as original images, and post-processed images.

[0048] In some embodiments, the image acquirer may acquire one or more images of a sample based on an imaging signal received from electron detection device 240. An imaging signal may correspond to a scanning operation for conducting charged particle imaging. An acquired image may be a single image comprising a plurality of imaging areas. The single image may be stored in the storage. The single image may be an original image that may be divided into a plurality of regions. Each of the regions may comprise one imaging area containing a feature of sample 208. The acquired images may comprise multiple images of a single imaging area of sample 208 sampled multiple times over a time sequence. The multiple images may be stored in the storage. In some embodiments, controller 109 may be configured to perform image processing steps with the multiple images of the same location of sample 208.

[0049] In some embodiments, controller 109 may include measurement circuitries (e.g., analog-to- digital converters) to obtain a distribution of the detected secondary electrons. The electron distribution data collected during a detection time window, in combination with corresponding scan path data of each of primary beamlets 211, 212, and 213 incident on the wafer surface, can be used to reconstruct images of the wafer structures under inspection. The reconstructed images can be used to reveal various features of the internal or external structures of sample 208, and thereby can be used to reveal any defects that may exist in the wafer.

[0050] In some embodiments, controller 109 may control motorized stage 209 to move sample 208 during inspection of sample 208. In some embodiments, controller 109 may enable motorized stage 209 to move sample 208 in a direction continuously at a constant speed. In other embodiments, controller 109 may enable motorized stage 209 to change the speed of the movement of sample 208 over time depending on the steps of scanning process.

[0051] Although Fig. 2A shows that apparatus 104 uses three primary electron beams, it is appreciated that apparatus 104 may use one, two, or more number of primary electron beams. The present disclosure does not limit the number of primary electron beams used in apparatus 104. In some embodiments, apparatus 104 may be a SEM used for lithography. In some embodiments, electron beam tool 104 may be a single-beam system or a multi-beam system.

[0052] For example, as shown in Fig. 2B, an electron beam tool 100B (also referred to herein as apparatus 100B) may be a single -beam inspection tool that is used in EBI system 10, consistent with embodiments of the present disclosure. Apparatus 100B includes a wafer holder 136 supported by motorized stage 134 to hold a wafer 150 to be inspected. Electron beam tool 100B includes an electron emitter, which may comprise a cathode 103, an anode 121, and a gun aperture 122. Electron beam tool 100B further includes a beam limit aperture 125, a condenser lens 126, a column aperture 135, an objective lens assembly 132, and a detector 144. Objective lens assembly 132, in some embodiments, may be a modified SORIL lens, which includes a pole piece 132a, a control electrode132b, a deflector 132c, and an exciting coil 132d. In an imaging process, an electron beam 161 emanating from the tip of cathode 103 may be accelerated by anode 121 voltage, pass through gun aperture 122, beam limit aperture 125, condenser lens 126, and be focused into a probe spot 170 by the modified SORIL lens and impinge onto the surface of wafer 150. Probe spot 170 may be scanned across the surface of wafer 150 by a deflector, such as deflector 132c or other deflectors in the SORIL lens. Secondary or scattered primary particles, such as secondary electrons or scattered primary electrons emanated from the wafer surface may be collected by detector 144 to determine intensity of the beam and so that an image of an area of interest on wafer 150 may be reconstructed.

[0053] There may also be provided an image processing system 199 that includes an image acquirer 120, a storage 130, and controller 109. Image acquirer 120 may comprise one or more processors. For example, image acquirer 120 may comprise a computer, server, mainframe host, terminals, personal computer, any kind of mobile computing devices, and the like, or a combination thereof. Image acquirer 120 may connect with detector 144 of electron beam tool 100B through a medium such as an electrical conductor, optical fiber cable, portable storage media, IR, Bluetooth, internet, wireless network, wireless radio, or a combination thereof. Image acquirer 120 may receive a signal from detector 144 and may construct an image. Image acquirer 120 may thus acquire images of wafer 150. Image acquirer 120 may also perform various post-processing functions, such as generating contours, superimposing indicators on an acquired image, and the like. Image acquirer 120 may be configured to perform adjustments of brightness and contrast, etc. of acquired images. Storage 130 may be a storage medium such as a hard disk, random access memory (RAM), cloud storage, other types of computer readable memory, and the like. Storage 130 may be coupled with image acquirer 120 and may be used for saving scanned raw image data as original images, and post-processed images. Image acquirer 120 and storage 130 may be connected to controller 109. In some embodiments, image acquirer 120, storage 130, and controller 109 may be integrated together as one electronic control unit.

[0054] In some embodiments, image acquirer 120 may acquire one or more images of a sample based on an imaging signal received from detector 144. An imaging signal may correspond to a scanning operation for conducting charged particle imaging. An acquired image may be a single image comprising a plurality of imaging areas that may contain various features of wafer 150. The single image may be stored in storage 130. Imaging may be performed on the basis of imaging frames.

[0055] The condenser and illumination optics of the electron beam tool may comprise or be supplemented by electromagnetic quadrupole electron lenses. For example, as shown in Fig. 2B, electron beam tool 100B may comprise a first quadrupole lens 148 and a second quadrupole lens 158. In some embodiments, the quadrupole lenses are used for controlling the electron beam. For example, first quadrupole lens 148 can be controlled to adjust the beam current and second quadrupole lens 158 can be controlled to adjust the beam spot size and beam shape.

[0056] Fig. 2B illustrates a charged particle beam apparatus in which an inspection system may use a single primary beam that may be configured to generate secondary electrons by interacting with wafer 150. Detector 144 may be placed along optical axis 105, as in the embodiment shown in Fig. 2B. The primary electron beam may be configured to travel along optical axis 105. Accordingly, detector 144 may include a hole at its center so that the primary electron beam may pass through to reach wafer 150.

[0057] Fig. 3 shows an exemplary charged particle system 300. As shown in Fig. 3 and legend 310, in typical systems, the temperature of the chamber body (e.g., main chamber 320) is noticeably raised due to heat transferring from on-chamber modules (e.g., e-modules 330). For example, the temperature of the ambient environment 340 may be less than the temperature of main chamber 320 (e.g., the temperature of the ambient environment may be 21 °C and the temperature of the main chamber may be 23-25 °C).

[0058] Typical systems suffer from constraints. For example, the higher temperature of main chamber 320 negatively affects system performance by impeding heat dissipation for modules directly connected to main chamber 320. For example, the higher temperature of main chamber 320 results in local hot spots with a risk of overheating e-modules 320 and main chamber 320, thereby causing thermal shift of high-precision metrology devices connected to main chamber 320 (e.g., causing a shift in SEM, laser positioning device, and reference mirrors, which are critical for positioning wafer stage 322) and causing thermal drift and loss of control accuracy of the wafer stage 322 itself due to heat transfer from main chamber 320 to wafer stage 322 (when the temperature of main chamber 320 is greater than the temperature of wafer stage 322) and heat accumulation (when the temperature of wafer stage 322 is greater than the temperature of main chamber 320) caused by an impeded heat transfer path. The higher temperature of main chamber 320 also results in thermal expansion of wafer 324 (e.g., due to heat transferred from wafer stage 322) and associated throughput loss of image shift, as well as tribological particle generation and contamination on the backside of wafer 324 (e.g., particles generated when wafer 324 expands while contacting wafer stage 322).

[0059] Because main chamber 320 serves as the general “heat sink” of all modules connected to main chamber 320 and all modules enclosed in main chamber 320 (e.g., wafer 324 and wafer stage 322 in the vacuum environment of main chamber 320), typical systems suffer from the negative consequences of a hot heat sink.

[0060] Typical systems may use individual water cooling 342 or 344 to cool components such as SEM 346 and wafer stage 322, which requires complex cooling loop designs with high volume and monetary investment. Additionally, for optimal module-level water cooling efficiency, cooling fluid is delivered near the sources of heat (e.g., coil of SEM 346, motors of wafer stage 322, etc.), which are usually in main chamber 320 in a deep vacuum environment. However, water cooling in a deep vacuum environment is disadvantageous with a high risk of outgassing (air trapped in the cooling fluid, which may slowly leak into the vacuum environment and constitute points of virtual leak) andcatastrophic consequences if leakage of the cooling loop occurs in the sensitive vacuum environment of main chamber 320.

[0061] Fig. 4 shows an exemplary charged particle system 400 (e.g., EBI system 100 of Fig. 1, electron beam tool 104 of Fig. 2A, electron beam tool 100B of Fig. 2B, charged particle system 700 of Fig. 7, etc.), consistent with embodiments of the present disclosure.

[0062] In some embodiments, charged particle system 400 may include water cooling armor (WCA) 452 and 454 for cooling main chamber 420. While two WCA 452 and 454 are shown in Fig. 4, it is appreciated that any number of WCAs may be used in charged particle system 400 (e.g., WCA 552, 554, 556 of Fig. 5, etc.). While WCAs 452 and 454 may be depicted as separate WCA components, it is appreciated that WCAs 452 and 454 may represent any number of WCAs, including a single continuous WCA that provides coverage over multiple surfaces of charged particle system 400.

[0063] WCAs 452 and 454 may be cold plates (e.g., metal plates embedded with long, loop-like narrow liquid channels for cooling water flow, with very high heat transfer efficiency, or a thermoelectric cooler (Peltier pad) with one side attached to heatsink and fans for proper heat transfer and removal) stacked or thermally mounted on the top of main chamber 420 (e.g., main chamber 101 of Fig. 1, main chamber 720 of Fig. 7, etc.) (e.g., a WCA may directly contact an outside surface of main chamber 420). For example, WCA 452 may be located beneath e-modules 430 and WCAs 452 and 454 may be located around SEM 446. In some embodiments, a WCA may directly contact e- modules 430 or SEM 446 (e.g., electron beam tool 104 of Figs. 1-2A, electron beam tool 100B of Fig. 2B, etc.). In some embodiments, a WCA may be adjacent to SEM 446.

[0064] Cooling fluid (e.g., water or coolant) may be provided by a chiller or facility cooling water (e.g., facility cooling water 560 of Fig. 5) (e.g., process cooling water), which may run through the cooling channels of WCAs 452 and 454 to remove heat transferred from main chamber 420 and from modules (e.g., e-modules 430, SEM 446, etc.) attached to main chamber 420.

[0065] In some embodiments, each of WCAs 452 and 454 may include mounting holes (e.g., mounting holes 570 of Fig. 5) to mount WCAs 452 and 454 onto main chamber 420 and to provide mounting positions for modules (e.g., e-modules 430, etc.), such that e-modules 430 are not directly attached to main chamber 420. A leak tray may be included near the inlet or outlet of the cooling flow towards WCAs 452 and 454 to collect any leakage as a safety measure.

[0066] In some embodiments, the setpoint temperature of cooling control of WCAs 452 and 454 may be similar to that of ambient environment 440. In some embodiments, the temperature of ambient environment 440 may be measured by a separate temperature sensor 470 in charged particle system 400. For example, a controller (not shown) may monitor or control the coolant water in each of WCAs 452 and 454 such that the temperature of each of WCAs 452 and 454 may be adjusted to adjust the temperature of e-modules 430 or SEM 446. In some embodiments, the temperature measured by sensor 470 may be used to adjust the temperature of e-modules 430 or SEM 446 to be similar or substantially the same as the temperature of ambient environment 440. In some embodiments, sensors(not shown) may be connected to e-modules 430, SEM 446, or main chamber 420 to measure the temperature of e-modules 430, SEM 446, or main chamber 420. For example, the temperature of WCAs 452 and 454 may be adjusted when a temperature of a WCA, a temperature of ambient environment 440, or a temperature of main chamber 420 are outside of a target temperature range.

[0067] While only sensor 470 is shown, it is appreciated that any number of sensors or controllers (e.g., controller 109 of Figs. 1, 2A, or 2B, etc.) may be included in charged particle system 400 to achieve the advantages described in embodiments of the present disclosure. In some embodiments, a single controller or sensor may be used while in some embodiments, multiple controllers or sensors may be used (e.g., one controller or sensor may be used for multiple WCA or a single controller or sensor may be used for multiple WCA).

[0068] Advantageously, charged particle system 400 may provide direct temperature control and cooling over on-chamber modules (e.g., e-modules 430, etc.). Instead of running a costly individual cooling loop over each high-power module attached to the chamber, WCAs 452 and 454 constitute an all-in-one high-performance cooling solution for the modules on main chamber 420.

[0069] Additionally, charged particle system 400 advantageously provides a much more stable chamber environment than in typical systems. Heat generated by modules attached to main chamber 420 will be quickly absorbed and removed from main chamber 420 due to the high heat transfer efficiency of WCAs 452 and 454 (e.g., cooling power > 10 kW), thereby resulting in a well- conditioned chamber environment with a stable temperature.

[0070] Although typical systems may include a cooling loop (e.g., cooling loop 462) running through the objective column of the SEM, the provided cooling power is sometimes insufficient because the heat source is near the interface between the SEM and the chamber, which is a distance away from the cooling loop located on the upper half of the SEM module. Charged particle system 400 advantageously adds cooling power to the top of main chamber 420 near the lower portion of SEM 446 and facilitates its cooling and temperature control. It is appreciated that cooling loops 462 and 464, which are typically used in existing systems, are optional components in charged particle system 400 and that charged particle system 400 may omit these cooling loops due to WCAs 452 and 454.

[0071] As discussed above, in-vacuum water-cooling (e.g., sending cooling water flow into the wafer stage in the vacuum chamber) is costly and risky. The WCA design of charged particle system 400 allows main chamber 420, which is essentially the “heat sink” of all in-vacuum modules, to be sufficiently cooled such that the heat of wafer stage 422 will dissipate quickly into main chamber 420. Since the major heat-transferring mode between wafer 424 and main chamber 420 is thermal radiation (e.g., very little heat flow, less than 1 W), the temperature of wafer 424 will be substantially identical to that of the chamber environment of main chamber 420. Therefore, temperature control of wafer 424 (e.g., sample 208 of Fig. 2A, wafer 150 of Fig. 2B, etc.) may be achieved by the temperature control of main chamber 420 via WCAs 452 and 454, without costly in- vacuum cooling (e.g., water-cooling the moving wafer stage 422).

[0072] Advantageously, when compared to conventional systems, charged particle system 400 prevents overheating and thermal shift of high-precision metrology devices connected to main chamber 420 (e.g., prevents causing a shift in SEM, laser positioning device, and reference mirrors, which are critical for positioning wafer stage 422 (e.g., motorized stage 209 of Fig. 2A, motorized stage 134 of Fig. 2B, wafer stage 722 of Fig. 7, etc.)). Charged particle system 400 also prevents thermal drift and loss of control accuracy of the wafer stage 422 itself and thermal expansion of wafer 424 and associated throughput loss of image shift. By preventing thermal expansion of wafer 424, charged particle system 400 also prevents tribological particle generation and contamination on the backside of wafer 424. Moreover, in charged particle system 400, outgassing and leakage may be avoided since individual water cooling is not needed.

[0073] Fig. 5 shows a top view 500 of the charged particle system of Fig. 4, consistent with embodiments of the present disclosure.

[0074] As shown in Fig. 5, a charged particle system (e.g., charged particle system 400 of Fig. 4) may include water cooling armor (WCA) 552, 554, and 556 for cooling the main chamber (e.g., main chamber 101 of Fig. 1, main chamber 420 of Fig. 4, main chamber 720 of Fig. 7, etc.). While three WCA 552, 554, and 556 are shown in Fig. 5, it is appreciated that any number of WCAs may be used in the charged particle system 400 (e.g., WCA 452 and 454 of Fig. 4, etc.). While WCAs 552, 554, and 556 may be depicted as separate WCA components, it is appreciated that WCAs 552, 554, and 556 may represent any number of WCAs, including a single continuous WCA that provides coverage over multiple surfaces of the charged particle system.

[0075] WCAs 552, 554, and 556 may be cold plates (e.g., metal plates embedded with long, loop-like narrow liquid channels for cooling water flow, with very high heat transfer efficiency, or a thermoelectric cooler (Peltier pad) with one side attached to heatsink and fans for proper heat transfer and removal) stacked or thermally mounted on the top of the main chamber (e.g., a WCA may directly contact an outside surface of the main chamber). For example, WCA 554 may be located around e-modules 430 and WCAs 552 and 556 may be located around SEM 446 (e.g., electron beam tool 104 of Figs. 1-2A, electron beam tool 100B of Fig. 2B, etc.). In some embodiments, a WCA may directly contact e-modules 430 or SEM 446. In some embodiments, a WCA may be adjacent to SEM 446.

[0076] Cooling fluid (e.g., water or coolant) may be provided by a chiller or facility cooling water 560 (e.g., process cooling water), which may run through the cooling channels of WCA 552, 554, and 556 to remove heat transferred from main chamber 420 and from modules (e.g., e-modules 430, SEM 446, etc.) attached to the main chamber. While one chiller or facility cooling water 560 is shown, it is appreciated that any number of chillers or facility cooling water may be included in the charged particle system (e.g., a single chiller for all WCA or multiple chillers for multiple WCA).

[0077] In some embodiments, each of WCA 552, 554, and 556 may include mounting holes 570 (in locations that do not conflict with the cooling channel) to mount WCA 552, 554, and 556 onto themain chamber and to provide mounting positions for modules (e.g., e-modules 430, etc.), such that e- modules 430 are not directly attached to the main chamber. A leak tray may be included near the inlet or outlet of the cooling flow towards WCA 552, 554, and 556 to collect any leakage as a safety measure.

[0078] In some embodiments, the setpoint temperature of cooling control of WCA 552, 554, and 556 may be similar to that of the ambient environment (e.g., ambient environment 440 of Fig. 4). In some embodiments, the temperature of the ambient environment may be measured by a separate temperature sensor in the charged particle system. For example, a controller (not shown) may monitor or control the coolant water in each of WCA 552, 554, and 556 such that the temperature of each of WCA 552, 554, and 556 may be adjusted to adjust the temperature of e-modules 430 or SEM 446. In some embodiments, the temperature measured by the sensor may be used to adjust the temperature of e-modules 430 or SEM 446 to be similar or substantially the same as the temperature of the ambient environment. In some embodiments, sensors (not shown) may be connected to e-modules 430, SEM 446, or the main chamber to measure the temperature of e-modules 430, SEM 446, or the main chamber. For example, the temperature of WCA 552, 554, or 556 may be adjusted when a temperature of a WCA, a temperature of the ambient environment, or a temperature of the main chamber are outside of a target temperature range.

[0079] In some embodiments, a single controller or sensor may be used while in some embodiments, multiple controllers or sensors may be used (e.g., one controller or sensor may be used for multiple WCA or a single controller or sensor may be used for multiple WCA).

[0080] Fig. 6 shows an exemplary charged particle system 600. Charged particle system 600 includes a vacuum environment 620 and an ambient environment 640. In typical systems, as shown in Fig. 6 (e.g., view 630), the wafer stage 622 “sits” on the bottom surface 652 of the main chamber in vacuum environment 620. Wafer stage 622 includes base plate 626 and feet 624 and may include shims in between feet 624 and the bottom surface 652 of the main chamber. While two feet 624 are shown in Fig. 6, it is appreciated that wafer stage 622 sits on the bottom surface 652 of the main chamber via four feet (with shims that may be inserted between each foot and the bottom surface 652 of the main chamber). The shims may locally adjust the height of wafer stage 622.

[0081] Typical systems suffer from constraints. For example, heat transfer efficiency between wafer stage 622 and the main chamber is minimal, due at least in part to the minimal contact area between wafer stage 622 and the bottom surface 652 of the main chamber (see, e.g., gap 628 between base plate 626 and the bottom surface 652 of the main chamber and cooling armor 650). This minimal contact area may lead to heat accumulation and thermal drifting of sensitive modules. As discussed above, water cooling also suffers from constraints (e.g., leakage, etc.). Moreover, increasing the contact area between wafer stage 622 and the main chamber would increase the difficulty in leveling wafer stage 622.

[0082] Fig. 7 shows an exemplary charged particle system 700 (e.g., EBI system 100 of Fig. 1, electron beam tool 104 of Fig. 2A, electron beam tool 100B of Fig. 2B, charged particle system 400 of Fig. 4, etc.), consistent with embodiments of the present disclosure.

[0083] In some embodiments, charged particle system 700 may include a wafer stage 722 (e.g., motorized stage 209 of Fig. 2A, motorized stage 134 of Fig. 2B, wafer stage 422 of Fig. 4, etc.) in a vacuum environment 720 and a cooling armor 750 (e.g., water cooling armor (WCA) 452, 454, 552, 554, and 556 of Figs. 4-5, etc.) in an ambient environment 740. As shown in Fig. 7, charged particle system 700 may include a heat transfer facilitator 760 (e.g., heat transfer apparatus) between a base plate 726 of wafer stage 722 and a bottom surface 754 of the main chamber (e.g., main chamber 101 of Fig. 1, main chamber 420 of Fig. 4, etc.). In some embodiments, cooling armor 750 may be on an outside surface of the main chamber directly opposite to base plate 726.

[0084] Advantageously, heat transfer facilitator 760 may increase heat transfer efficiency between wafer stage 722 and the main chamber without increasing the contact area between wafer stage 722 and the bottom surface 752 of the main chamber. Therefore, thermal drifting of sensitive modules may be prevented.

[0085] As shown in view 770, heat transfer facilitator 760 may include deformation components 762, 764, or some combination of different shapes. Deformation components 762 may be fin-shaped and deformation portions 764 may be coil-shaped.

[0086] In some embodiments, deformation components 762 or 764 may be deformed from the bottom surface 754 of the main chamber or from base plate 726 of wafer stage 722 (e.g., deformation components 762 or 764 may be deformable from force applied by base plate 726 or bottom surface 754 of the main chamber). In some embodiments, deformation components 762 or 764 of heat transfer facilitator 760 are needed because of the high precision requirements of wafer stage 722. For example, when wafer stage 722 is installed, its height may be adjusted and calibrated during leveling of wafer stage 722. Advantageously, deformation components 762 or 764 may increase heat transfer efficiency between wafer stage 722 and the main chamber without negatively impacting leveling of wafer stage 722.

[0087] Fig. 8 shows an exemplary process 800 for cooling in a charged particle system (e.g., EBI system 100 of Fig. 1, electron beam tool 104 of Fig. 2A, electron beam tool 100B of Fig. 2B, charged particle system 400 of Fig. 4, charged particle system 700 of Fig. 7, etc.), consistent with embodiments of the present disclosure.

[0088] At step 802, a cooling platform (e.g., water cooling armor (WCA) 452, 454, 552, 554, and 556 of Figs. 4-5; cooling armor 750 of Fig. 7, etc.) mounted to a vacuum chamber (e.g., main chamber 101 of Fig. 1, main chamber 420 of Fig. 4, main chamber 720 of Fig. 7, etc.), may hold and cool a plurality of modules (e.g., e-modules 430 of Figs. 4-5, etc.).

[0089] In some embodiments, the charged particle system may include any number of cooling platforms, including a single continuous cooling platform that provides coverage over multiple surfaces of the charged particle system.

[0090] The cooling platforms may be cold plates, such as metal plates embedded with long, loop-like narrow liquid channels for cooling water flow, with very high heat transfer efficiency. In some embodiments, the cooling platforms may be a thermoelectric cooler (Peltier pad) with one side attached to a heatsink and fans for proper heat transfer and removal. In some embodiments, the cooling platforms may be stacked or thermally mounted on the top of the main chamber (e.g., a cooling platform may directly contact an outside surface of the main chamber). For example, the cooling platform may be located beneath the e-modules or located around the e-modules. In some embodiments, a WCA may directly contact the e-modules or the SEM (e.g., electron beam tool 104 of Figs. 1-2A, electron beam tool 100B of Fig. 2B, SEM 446 of Figs. 4-5, etc.). In some embodiments, a cooling platform may be adjacent to the SEM.

[0091] Cooling fluid (e.g., water or coolant) may be provided by a chiller or facility cooling water (e.g., 560 chiller or facility cooling water of Fig. 5, etc.) (e.g., process cooling water), which may run through the cooling channels of the cooling platforms to remove heat transferred from the main chamber and from modules (e.g., the e-modules, the SEM, etc.) attached to the main chamber. It is appreciated that any number of chillers or facility cooling water systems may be included in the charged particle system (e.g., a single chiller for all cooling platforms or multiple chillers for multiple cooling platforms).

[0092] In some embodiments, each of the cooling platforms may include mounting holes (e.g., mounting holes 570 of Fig. 5, etc.) (in locations that do not conflict with the cooling channel) to mount the cooling platforms onto the main chamber and to provide mounting positions for the modules, such that the e-modules are not directly attached to the main chamber. A leak tray may be included near the inlet or outlet of the cooling flow towards the cooling platforms to collect any leakage as a safety measure.

[0093] At step 804, a controller (e.g., controller 109 of Figs. 1, 2A, 2B, etc.) may monitor a temperature of the cooling platform. In some embodiments, the setpoint temperature of cooling control of the cooling platforms may be similar to that of the ambient environment (e.g., ambient environment 440 of Fig. 4, ambient environment 740 of Fig. 7, etc.).

[0094] At step 806, the controller may monitor a temperature of the vacuum chamber or a temperature of the ambient environment. In some embodiments, the temperature of the ambient environment may be measured by a separate temperature sensor (e.g., temperature sensor 470 of Fig. 4, etc.) in the charged particle system.

[0095] At step 808, the controller may adjust the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment. For example, the controller may monitor or control the coolant water ineach of the cooling platforms such that the temperature of each of the cooling platforms may be adjusted to adjust the temperature of the e-modules or the SEM.

[0096] In some embodiments, the temperature measured by the sensor may be used to adjust the temperature of the e-modules or the SEM to be similar or substantially the same as the temperature of the ambient environment. In some embodiments, sensors may be connected to the e-modules, the SEM, or the main chamber to measure the temperature of the e-modules, the SEM, or the main chamber. For example, the temperature of the cooling platforms may be adjusted when a temperature of a cooling platform, a temperature of the ambient environment, or a temperature of the main chamber are outside of a target temperature range.

[0097] In some embodiments, the charged particle system may include a heat transfer facilitator (e.g., a heat transfer apparatus, heat transfer facilitator 760 of Fig. 7, etc.) between a base plate (e.g., base plate 726 of Fig. 7, etc.) of a wafer stage (e.g., wafer stage 422 of Fig. 4, wafer stage 722 of Fig. 7, etc.) and a bottom surface (e.g., bottom surface 754 of Fig. 7, etc.) of the main chamber. In some embodiments, a cooling armor (e.g., WCA 452, 454, 552, 554, and 556 of Figs. 4-5; cooling armor 750 of Fig. 7, etc.) may be on an outside surface of the main chamber directly opposite to the base plate.

[0098] Advantageously, the heat transfer facilitator may increase heat transfer efficiency between the wafer stage and the main chamber without increasing the contact area between the wafer stage and the bottom surface of the main chamber. Therefore, thermal drifting of sensitive modules may be prevented.

[0099] In some embodiments, the heat transfer facilitator may include deformation components (e.g., deformation components 762, 764, or some combination of different shapes of Fig. 7, etc.). The deformation components may be fin-shaped or coil-shaped.

[0100] In some embodiments, the deformation components may be deformed from the bottom surface of the main chamber or from the base plate of the wafer stage (e.g., the deformation components may be deformable from force applied by the base plate or the bottom surface of the main chamber). In some embodiments, the deformation components of the heat transfer facilitator are needed because of the high precision requirements of the wafer stage. For example, when the wafer stage is installed, its height may be adjusted and calibrated during leveling of the wafer stage.Advantageously, the deformation components may increase heat transfer efficiency between the wafer stage and the main chamber without negatively impacting leveling of the wafer stage.

[0101] A non-transitory computer readable medium may be provided that stores instructions for a processor of a controller (e.g., controller 109 of Figs. 1, 2A, 2B, etc.) for controlling the electron beam tool or other systems, or components thereof, consistent with embodiments in the present disclosure. These instructions may allow the one or more processors to carry out temperature monitoring, temperature sensing, temperature adjustment, temperature adjustment of a cooling platform, image processing, data processing, beamlet scanning, graphical display, operations of acharged particle beam apparatus, or another imaging device, or the like for providing operations consistent with those described above for Figs. 4, 7, and 8. In some embodiments, the non-transitory computer readable medium may be provided that stores instructions for a processor to perform the steps of process 800. Common forms of non-transitory media include, for example, a floppy disk, a flexible disk, hard disk, solid state drive, magnetic tape, or any other magnetic data storage medium, a Compact Disc Read Only Memory (CD-ROM), any other optical data storage medium, any physical medium with patterns of holes, a Random Access Memory (RAM), a Programmable Read Only Memory (PROM), and Erasable Programmable Read Only Memory (EPROM), a FLASH-EPROM or any other flash memory, Non-Volatile Random Access Memory (NVRAM), a cache, a register, any other memory chip or cartridge, and networked versions of the same.

[0102] The embodiments may further be described using the following clauses:1. A system for cooling in a charged particle system, the system comprising: a wafer stage for holding a wafer in a vacuum chamber; a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold and cool a plurality of modules; and a controller having one or more processors and configured to: monitor a temperature of the cooling platform; monitor a temperature of the vacuum chamber or a temperature of an ambient environment; and adjust the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.2. The system of clause 1, wherein the cooling platform comprises a plate.3. The system of clause 2, wherein the plate is embedded with liquid channels for cooling fluid.4. The system of clause 3, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.5. The system of any one of clauses 3-4, wherein the cooling fluid is provided by a chiller.6. The system of any one of clauses 1-5, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.7. The system of clause 6, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.8. The system of any one of clauses 1-7, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.9. The system of any one of clauses 1-8, wherein the cooling platform comprises a plurality of cooling platforms.10. The system of clause 9, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).11. The system of clause 10, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.12. The system of any one of clauses 1-11, wherein the cooling platform directly contacts the plurality of modules.13. The system of any one of clauses 1-12, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.14. The system of any one of clauses 1-13, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.15. The system of clause 14, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.16. The system of any one of clauses 14-15, wherein the deformation portions are fin-shaped.17. The system of any one of clauses 14-16, wherein the deformation portions are coil-shaped.18. The system of any one of clauses 14-17, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.19. A system for cooling in a charged particle system, the system comprising: a wafer stage for holding a wafer in a vacuum chamber; a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold a plurality of modules and to transfer heat from the plurality of modules to the cooling platform; and a controller configured to adjust heat transfer from the plurality of modules to the cooling platform by adjusting a temperature of the cooling platform based on the temperature of the cooling platform, a temperature of the vacuum chamber, or a temperature of the ambient environment.20. The system of clause 19, wherein the cooling platform comprises a plate.21. The system of clause 20, wherein the plate is embedded with liquid channels for cooling fluid.22. The system of clause 21, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.23. The system of any one of clauses 21-22, wherein the cooling fluid is provided by a chiller.24. The system of any one of clauses 19-23, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.25. The system of clause 24, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.26. The system of any one of clauses 19-25, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.27. The system of any one of clauses 19-26, wherein the cooling platform comprises a plurality of cooling platforms.28. The system of clause 27, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).29. The system of clause 28, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.30. The system of any one of clauses 19-29, wherein the cooling platform directly contacts the plurality of modules.31. The system of any one of clauses 19-30, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.32. The system of any one of clauses 19-31, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.33. The system of clause 32, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.34. The system of any one of clauses 32-33, wherein the deformation portions are fin-shaped.35. The system of any one of clauses 32-34, wherein the deformation portions are coil-shaped.36. The system of any one of clauses 32-35, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.37. A system for cooling in a charged particle system, the system comprising: a wafer stage for holding a wafer in a vacuum chamber, the wafer stage comprising: a base plate; a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber; and a cooling platform on an outside surface of the vacuum chamber directly opposite to the base plate.38. The system of clause 37, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.39. The system of any one of clauses 37-38, wherein the deformation portions are fin-shaped.40. The system of any one of clauses 37-39, wherein the deformation portions are coil-shaped.41. The system of any one of clauses 37-40, wherein the cooling platform is a first cooling platform and further comprising a second cooling platform mounted to the vacuum chamber, the second cooling platform configured to hold and cool a plurality of modules; and a controller having one or more processors and configured to: monitor a temperature of the second cooling platform; monitor a temperature of the vacuum chamber or a temperature of an ambient environment; and adjust the temperature of the second cooling platform based on the temperature of the second cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.42. The system of clause 41, wherein the second cooling platform comprises a plate.43. The system of clause 42, wherein the plate is embedded with liquid channels for cooling fluid.44. The system of clause 43, wherein adjustment of the temperature of the second cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.45. The system of any one of clauses 43-44, wherein the cooling fluid is provided by a chiller.46. The system of any one of clauses 41-45, wherein adjustment of the temperature of the second cooling platform is based on a target temperature range.47. The system of clause 46, wherein the temperature of the second cooling platform is adjusted when the temperature of the second cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.48. The system of any one of clauses 41-47, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.49. The system of any one of clauses 41-48, wherein the second cooling platform comprises a plurality of cooling platforms.50. The system of clause 49, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).51. The system of clause 50, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.52. The system of any one of clauses 41-51, wherein the second cooling platform directly contacts the plurality of modules.53. The system of any one of clauses 41-52, wherein the second cooling platform directly contacts an outside surface of the vacuum chamber.54. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform operations for cooling in a charged particle system, the charged particle system comprising a wafer stage for holding a wafer in a vacuum chamber, a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold and to cool a plurality of modules, the operations comprising:monitoring a temperature of the cooling platform; monitoring a temperature of the vacuum chamber or a temperature of an ambient environment; and adjusting the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.55. The non-transitory computer readable medium of clause 54, wherein the cooling platform comprises a plate.56. The non-transitory computer readable medium of clause 55, wherein the plate is embedded with liquid channels for cooling fluid.57. The non-transitory computer readable medium of clause 56, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.58. The non-transitory computer readable medium of any one of clauses 56-57, wherein the cooling fluid is provided by a chiller.59. The non-transitory computer readable medium of any one of clauses 54-58, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.60. The non-transitory computer readable medium of clause 59, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.61. The non-transitory computer readable medium of any one of clauses 54-60, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.62. The non-transitory computer readable medium of any one of clauses 54-61, wherein the cooling platform comprises a plurality of cooling platforms.63. The non-transitory computer readable medium of clause 62, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).64. The non-transitory computer readable medium of clause 63, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.65. The non-transitory computer readable medium of any one of clauses 54-64, wherein the cooling platform directly contacts the plurality of modules.66. The non-transitory computer readable medium of any one of clauses 54-65, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.67. The non-transitory computer readable medium of any one of clauses 54-66, wherein the wafer stage further comprises: a base plate; anda heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.68. The non-transitory computer readable medium of clause 67, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.69. The non-transitory computer readable medium of any one of clauses 67-68, wherein the deformation portions are fin-shaped.70. The non-transitory computer readable medium of any one of clauses 67-69, wherein the deformation portions are coil-shaped.71. The non-transitory computer readable medium of any one of clauses 67-70, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.72. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform operations for cooling in a charged particle system, the charged particle system comprising a wafer stage for holding a wafer in a vacuum chamber, a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold a plurality of modules and to transfer heat from the plurality of modules to the cooling platform, the operations comprising: adjusting heat transfer from the plurality of modules to the cooling platform by adjusting a temperature of the cooling platform based on the temperature of the cooling platform, a temperature of the vacuum chamber, or a temperature of the ambient environment.73. The non-transitory computer readable medium of clause 72, wherein the cooling platform comprises a plate.74. The non-transitory computer readable medium of clause 73, wherein the plate is embedded with liquid channels for cooling fluid.75. The non-transitory computer readable medium of clause 74, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.76. The non-transitory computer readable medium of any one of clauses 74-75, wherein the cooling fluid is provided by a chiller.77. The non-transitory computer readable medium of any one of clauses 72-76, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.78. The non-transitory computer readable medium of clause 77, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.79. The non-transitory computer readable medium of any one of clauses 72-78, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.80. The non-transitory computer readable medium of any one of clauses 72-79, wherein the cooling platform comprises a plurality of cooling platforms.81. The non-transitory computer readable medium of clause 80, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).82. The non-transitory computer readable medium of clause 81, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.83. The non-transitory computer readable medium of any one of clauses 72-82, wherein the cooling platform directly contacts the plurality of modules.84. The non-transitory computer readable medium of any one of clauses 72-83, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.85. The non-transitory computer readable medium of any one of clauses 72-84, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.86. The non-transitory computer readable medium of clause 85, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.87. The non-transitory computer readable medium of any one of clauses 85-86, wherein the deformation portions are fin-shaped.88. The non-transitory computer readable medium of any one of clauses 85-87, wherein the deformation portions are coil-shaped.89. The non-transitory computer readable medium of any one of clauses 85-88, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.90. A method for cooling in a charged particle system, the charged particle system comprising a wafer stage for holding a wafer in a vacuum chamber, a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold and to cool a plurality of modules, the method comprising: monitoring a temperature of the cooling platform; monitoring a temperature of the vacuum chamber or a temperature of an ambient environment; and adjusting the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.91. The method of clause 90, wherein the cooling platform comprises a plate.92. The method of clause 91, wherein the plate is embedded with liquid channels for cooling fluid.93. The method of clause 92, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.94. The method of any one of clauses 92-93, wherein the cooling fluid is provided by a chiller.95. The method of any one of clauses 90-94, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.96. The method of clause 95, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.97. The method of any one of clauses 90-96, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.98. The method of any one of clauses 90-97, wherein the cooling platform comprises a plurality of cooling platforms.99. The method of clause 98, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).100. The method of clause 99, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.101. The method of any one of clauses 90-100, wherein the cooling platform directly contacts the plurality of modules.102. The method of any one of clauses 90-101, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.103. The method of any one of clauses 90-102, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.104. The method of clause 103, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.105. The method of any one of clauses 103-104, wherein the deformation portions are fin-shaped.106. The method of any one of clauses 103-105, wherein the deformation portions are coil-shaped.107. The method of any one of clauses 103-106, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.108. A method for cooling in a charged particle system, the charged particle system comprising a wafer stage for holding a wafer in a vacuum chamber, a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold a plurality of modules and to transfer heat from the plurality of modules to the cooling platform, the method comprising:adjusting heat transfer from the plurality of modules to the cooling platform by adjusting a temperature of the cooling platform based on the temperature of the cooling platform, a temperature of the vacuum chamber, or a temperature of the ambient environment.109. The method of clause 108, wherein the cooling platform comprises a plate.110. The method of clause 109, wherein the plate is embedded with liquid channels for cooling fluid.111. The method of clause 110, wherein adjustment of the temperature of the cooling platform comprises an adjusting of a flow rate or a temperature of the cooling liquid.112. The method of any one of clauses 110-111, wherein the cooling fluid is provided by a chiller.113. The method of any one of clauses 108-112, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.114. The method of clause 113, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.115. The method of any one of clauses 108-114, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.116. The method of any one of clauses 108-115, wherein the cooling platform comprises a plurality of cooling platforms.117. The method of clause 116, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).118. The method of clause 117, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.119. The method of any one of clauses 108-118, wherein the cooling platform directly contacts the plurality of modules.120. The method of any one of clauses 108-119, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.121. The method of any one of clauses 108-120, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.122. The method of clause 121, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.123. The method of any one of clauses 121-122, wherein the deformation portions are fin-shaped.124. The method of any one of clauses 121-123, wherein the deformation portions are coil-shaped.125. The method of any one of clauses 121-124, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.

[0103] It will be appreciated that the embodiments of the present disclosure are not limited to the exact construction that has been described above and illustrated in the accompanying drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

CLAIMS1. A non-transitory computer readable medium that stores a set of instructions that is executable by at least one processor of a computing device to cause the computing device to perform operations for cooling in a charged particle system, the charged particle system comprising a wafer stage for holding a wafer in a vacuum chamber, a cooling platform mounted to the vacuum chamber, the cooling platform configured to hold and to cool a plurality of modules, the operations comprising: monitoring a temperature of the cooling platform; monitoring a temperature of the vacuum chamber or a temperature of an ambient environment; and adjusting the temperature of the cooling platform based on the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment.

2. The non-transitory computer readable medium of claim 1, wherein adjustment of the temperature of the cooling platform is based on a target temperature range.

3. The non-transitory computer readable medium of claim 2, wherein the temperature of the cooling platform is adjusted when the temperature of the cooling platform, the temperature of the vacuum chamber, or the temperature of the ambient environment is outside of the target temperature range.

4. The non-transitory computer readable medium of claim 1, where the plurality of modules comprises a scanning electron microscope (SEM) or modules associated with the SEM.

5. The non-transitory computer readable medium of claim 1, wherein the cooling platform comprises a plurality of cooling platforms.

6. The non-transitory computer readable medium of claim 5, wherein the plurality of cooling platforms comprises at least one cooling platform adjacent to a scanning electron microscope (SEM).

7. The non-transitory computer readable medium of claim 6, wherein the at least one cooling platform adjacent to the SEM directly contacts the SEM.

8. The non-transitory computer readable medium of claim 1, wherein the cooling platform directly contacts the plurality of modules.

9. The non-transitory computer readable medium of claim 1, wherein the cooling platform directly contacts an outside surface of the vacuum chamber.

10. The non-transitory computer readable medium of claim 1, wherein the wafer stage further comprises: a base plate; and a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber.

11. The non-transitory computer readable medium of claim 10, wherein the deformation portions contact the base plate and the inner surface of the vacuum chamber.

12. The non-transitory computer readable medium of claim 10, wherein the deformation portions are fin-shaped.

13. The non-transitory computer readable medium of claim 10, wherein the deformation portions are coil-shaped.

14. The non-transitory computer readable medium of claim 10, wherein the cooling platform comprises a plurality of cooling platforms and a cooling platform of the plurality of cooling platforms is on an outside surface of the vacuum chamber directly opposite to the base plate.

15. A system for cooling in a charged particle system, the system comprising: a wafer stage for holding a wafer in a vacuum chamber, the wafer stage comprising: a base plate; a heat transfer apparatus between the base plate and an inner surface of the vacuum chamber, the heat transfer apparatus comprising deformation portions configured to be deformed by the base plate or the inner surface of the vacuum chamber; and a cooling platform on an outside surface of the vacuum chamber directly opposite to the base plate.

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