High throughput load lock chamber

Abstract

An improved vacuum chamber for a system for processing wafers is provided. The vacuum chamber may include a top wall, wherein at least a portion of an inner surface of the top wall is inclined relative to a side view of the top wall. The vacuum chamber may also include a vent coupled to the top wall and a baffle coupled to the vacuum chamber and positioned below the vent, wherein the baffle is configured to reduce turbulence of gas entering the vacuum chamber via the vent.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Application No. 63 / 433,702, filed Dec. 19, 2022, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] Embodiments provided herein disclose a particle beam inspection apparatus, and more particularly disclose an improved load lock chamber that can be used in a particle beam inspection apparatus. BACKGROUND ART

[0004] When manufacturing semiconductor integrated circuit (IC) chips, pattern defects and / or uninvited particles (residues) inevitably occur on wafers and / or masks during the manufacturing process, thereby greatly reducing the yield. For example, for patterns with small critical feature sizes that have been adopted to meet the increasingly advanced performance requirements of IC chips, uninvited particles can be troublesome.

[0005] Pattern inspection tools using charged particle beams have been used to detect defects or uninvited particles. These tools typically employ a scanning electron microscope (SEM). In an SEM, a primary electron beam with a relatively high energy is decelerated to land on a sample with a relatively low landing energy and is focused to form a probing point thereon. Due to this focused probing point of the primary electrons, secondary electrons will be generated from the surface. By scanning the probing point on the sample surface and collecting the secondary electrons, the pattern inspection tool can acquire an image of the sample surface.

[0006] During the operation of the inspection tool, a wafer is typically fixed by a wafer stage in the main chamber. The inspection tool may include a wafer positioning device for positioning the wafer stage and the wafer relative to the electron beam. This can be used to position a target area on the wafer, i.e., the area to be inspected, within the working range of the electron beam. During the inspection process, the main chamber is maintained in a deep vacuum state. The inspection tool may also include a small vacuum chamber called a load lock chamber, which is typically connected to the large main chamber through a door between the chambers. The load lock chamber is used to transfer wafers between an atmospheric clean room environment and the main chamber in a deep vacuum state. The wafer is first loaded into the load lock chamber in the atmosphere. Then, the load lock chamber is pumped down to a high vacuum pressure. Then, the door connected to the main chamber is opened, and then, the wafer is mechanically transferred into the main chamber. After the wafer is processed or inspected, the wafer is transferred back to the load lock chamber, and then, the load lock chamber is vented to increase the pressure to the atmospheric level. During this process, the main chamber is always maintained in a high vacuum state. The load lock chamber allows wafers to be transferred into or out of the main chamber without venting the main chamber to the atmosphere. Summary of the Invention

[0007] Embodiments provided herein disclose a charged particle beam apparatus, and more particularly disclose an improved load lock chamber.

[0008] One aspect of the present disclosure relates to a vacuum chamber for a system configured to process wafers. The vacuum chamber may include a top wall, wherein at least a portion of the inner surface of the top wall is inclined with respect to a side view of the top wall. The vacuum chamber may further include a gas vent port coupled to the top wall and a baffle coupled to the vacuum chamber and positioned below the gas vent port, wherein the baffle is configured to reduce turbulence of gas entering the vacuum chamber via the gas vent port.

[0009] Another aspect of the present invention relates to a vacuum chamber including a top wall having an inner surface facing the interior of the vacuum chamber. The vacuum chamber may further include a gas vent port coupled to the top wall and configured to supply gas into the vacuum chamber. At least a portion of the inner surface of the top wall is inclined at a downward angle from the position of the gas vent port, and the vacuum chamber is configured to accommodate a wafer and hold the wafer on a wafer stage.

[0010] Other advantages of the present invention will become apparent from the following description in conjunction with the drawings, in which certain embodiments of the present invention are illustrated by way of illustration and example. Brief Description of the Drawings

[0011] The above and other aspects of the present disclosure will become more apparent from the following description of exemplary embodiments in conjunction with the drawings.

[0012] Figure 1A is a schematic diagram illustrating an exemplary charged particle beam inspection system consistent with an embodiment of the present disclosure.

[0013] Figure 1B is a schematic diagram illustrating an exemplary wafer loading sequence in a charged particle beam inspection system consistent with an embodiment of the present disclosure Figure 1A thereof.

[0014] Figure 2 is a schematic diagram illustrating a load lock chamber having a conventional configuration.

[0015] Figure 3A , Figure 3B and Figure 3C are schematic diagrams illustrating exemplary load lock chambers consistent with embodiments of the present disclosure.

[0016] Figure 4A and Figure 4B are schematic diagrams illustrating additional exemplary configurations of a load lock chamber consistent with embodiments of the present disclosure. Detailed Description

[0017] Reference will now be made in detail to exemplary embodiments, 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 elements unless otherwise noted. The implementations set forth in the description of the following exemplary embodiments do not represent all implementations consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with aspects related to the present invention as recited in the appended claims.

[0018] An electronic device is composed of circuits formed on a silicon wafer called a substrate. Semiconductor materials can include, for example, silicon, gallium arsenide, indium phosphide, or silicon germanium, etc. Many circuits can be formed together on the same silicon wafer and are called integrated circuits or ICs. The size of these circuits has decreased sharply, so more of these circuits can be installed on the substrate. For example, an IC chip in a smartphone can be as small as a thumb, but can include more than 10 billion transistors, each transistor being less than 1 / 1000 the size of a human hair.

[0019] Manufacturing these ICs with so many extremely small transistors is a complex, time-consuming, and expensive process, generally involving hundreds of individual manufacturing steps. Even an error in one step has the potential to cause defects in the finished IC, making it unusable. Therefore, one goal of the manufacturing process is to avoid such defects to maximize the number of functional ICs manufactured in the process, that is, to increase the overall yield of the process.

[0020] One component of increasing the yield is to monitor the chip manufacturing process to ensure that it produces a sufficient number of functional ICs. One method for monitoring the process is to inspect the chip circuit structure at various stages of its formation. The inspection can be carried out using inspection tools such as, for example, a scanning charged particle microscope (SCPM). For example, the SCPM can be a scanning electron microscope (SEM). The SEM can be used to create images of these extremely small structures, effectively "taking pictures" of the structures. These images can be used to determine whether the structures are formed correctly and whether they are formed in the correct positions. If the structures are defective, the process can be adjusted so that the defect is less likely to occur again.

[0021] Although an IC chip manufacturing facility requires a high process yield, it is also important to maintain a high wafer throughput (defined as the number of wafers processed per hour). High process yield and high wafer throughput can be affected by the presence of defects, especially when these defects require operator intervention for closer inspection. Therefore, high-throughput detection and identification of micron- and nano-scale defects by inspection tools such as SEMs are crucial for maintaining high yield and low cost.

[0022] To increase throughput and image quality, the main inspection chamber is maintained at a deep vacuum throughout the operation to allow a particle beam (such as electrons) to travel unimpeded within the main chamber and to prevent discharges (e.g., arcing) in the gun assembly. The inspection tool may include a small vacuum chamber known as a load lock chamber that is connected to the large main chamber. The load lock chamber is used to transfer wafers between the atmospheric cleanroom environment and the main chamber under deep vacuum conditions. For example, to transfer a wafer into the main chamber for inspection, the wafer is first loaded into the load lock chamber and then depressurized to match the vacuum level of the main chamber. Then the door connecting the load lock chamber and the main chamber is opened, and the wafer is mechanically transferred into the main chamber. After inspection, the wafer is again placed back into the load lock chamber, which is still at the same vacuum level as the main chamber, the door is closed, and then gas is vented into the load lock chamber to restore the pressure of the chamber to atmospheric level.

[0023] One aspect of the present disclosure includes an improved load lock chamber that increases the throughput of the overall inspection system. Compared with conventional particle beam inspection systems, the improved load lock system prepares wafers in a way that speeds up the inspection process and reduces the chance of introducing unwanted particles. The improved load lock system also provides an unobstructed view of the wafer for various built-in tools (e.g., sensors and vacuum tools), thereby enhancing the overall adjustability of the inspection system.

[0024] For example, a conventional load lock chamber is equipped with a large baffle configured to direct the flow of venting gas. The baffle is typically larger than the wafer to protect the entire surface of the wafer from contamination that the flow of venting gas might cause. However, such a large baffle requires a large internal volume of the load lock chamber, which results in longer pumping down (i.e., removing gas molecules to reach a high vacuum level) and venting up (i.e., venting gas into the chamber to reach atmospheric level) times. Additionally, since the large baffle is placed right between the top wall of the chamber and the wafer, it obscures various tools located at the top wall, such as laser / infrared sensors and vacuum tools, thus limiting the usability of such tools. The improved load lock chamber has a redesigned structure to enable a smaller load lock chamber. It also allows unobstructed viewing of the wafer by various built-in tools (e.g., sensors and vacuum tools) at the top of the load lock chamber.

[0025] For the sake of clarity, the relative size of the components in the drawings may be exaggerated. In the following description of the drawings, the same or similar reference numerals refer to the same or similar components or entities, and only the difference with the individual embodiments is described. As used herein, unless otherwise specifically stated, the term "or" includes all possible combinations unless it is not feasible. For example, if it is specified that a component can include A or B, then, unless otherwise specifically stated or not feasible, the component can include A or B or A and B. As a second example, if it is specified that a component can include A, B or C, then, unless otherwise specifically stated or not feasible, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C.

[0026] Reference now Figure 1A , which is a schematic diagram illustrating an exemplary charged particle beam inspection system 100 consistent with an embodiment of the present disclosure. Figure 1A As shown, the charged particle beam inspection system 100 includes a main chamber 10, a load lock chamber 20, an electron beam tool 40 and an equipment front end module (EFEM) 30. The electron beam tool 40 is located in the main chamber 10. Although the description and the drawings are directed to electron beams, it should be understood that the embodiments are not intended to limit the present invention to specific charged particles. It should also be understood that the electron beam tool 40 can be a single beam tool using a single electron beam or a multi-beam tool using multiple electron beams.

[0027] The EFEM 30 includes a first load port 30a and a second load port 30b. The EFEM 30 may include (one or more) additional load ports. The first load port 30a and the second load port 30b may, for example, accommodate a front opening unified box (FOUP) containing wafers (e.g., semiconductor wafers or wafers made of (one or more) other materials) or samples to be inspected (wafers and samples are collectively referred to as "wafers" hereinafter). One or more robotic arms (e.g., Figure 1B The wafer is transported to the load lock chamber 20 by a robot arm (shown).

[0028] although Figure 1A The load lock chamber 20 is shown to be located within the main chamber 10, but it should be further understood that the load lock chamber 20 can be located next to the main chamber, immediately outside the main chamber, such as Figure 2 shown.

[0029] The load lock chambers 20 can be accessed by doors between the chambers (e.g., Figure 1B The load lock chamber 20 may include a sample holder (e.g., Figure 2 The load lock chamber 20 may also include a mechanical transfer device (e.g.,Figure 1B of the robotic arm 12). The load lock chamber 20 can be connected to a load lock vacuum pump system (e.g., Figure 2 the vacuum port 280), which removes gas molecules from the load lock chamber 20 to achieve a first pressure below atmospheric pressure. After achieving the first pressure, one or more robotic arms (such as Figure 1B shown) transport the wafer from the load lock chamber 20 to the main chamber 10. In some embodiments, the main chamber 10 can also be connected to its own vacuum pump system (not shown), which removes gas molecules from the main chamber 10 to achieve a second pressure corresponding to a deeper vacuum state than the first pressure. After achieving the second pressure, the wafer is inspected by the electron beam tool 40.

[0030] The controller 50 is electrically connected to the electron beam tool 40. The controller 50 can be a computer configured to perform various controls of the charged particle beam inspection system 100. Although the controller 50 is Figure 1A shown in as being located outside the structure including the main chamber 10, the load lock chamber 20, and the EFEM 30, it should be understood that the controller 50 can be a part of this structure. Although the present disclosure provides an example of the main chamber 10 that houses the electron beam inspection tool, it should be noted that aspects of the present disclosure are not limited in the broadest sense to a chamber that houses the electron beam inspection tool. Instead, it should be understood that the above principles can also be applied to other tools operating at the second pressure.

[0031] In some embodiments, the controller 50 can include one or more processors (not shown). The processor can be a general-purpose or specific electronic device capable of manipulating or processing information. For example, the processor can include any number of central processing units (or "CPUs"), graphics processing units (or "GPUs"), optical processors, programmable logic controllers, microcontrollers, microprocessors, digital signal processors, hardware accelerators, intellectual property (IP) cores, programmable logic arrays (PLAs), programmable array logic (PALs), generic array logic (GALs), complex programmable logic devices (CPLDs), field programmable gate arrays (FPGAs), systems on a chip (SoCs), application-specific integrated circuits (ASICs), and any combination of any type of circuit capable of data processing. The processor can also be a virtual processor that includes one or more processors distributed across multiple machines or devices coupled via a network.

[0032] In some embodiments, the controller 50 may also include one or more memories (not shown). The memory may be a general or specific electronic device capable of storing processor-accessible code and data (e.g., via a bus). For example, the memory may include any number of random access memories (RAM), read-only memories (ROM), optical disks, magnetic disks, hard disks, solid-state drives, flash drives, secure digital (SD) cards, memory sticks, compact flash (CF) cards, or any combination of any type of storage device. The code and data may include an operating system (OS) and one or more applications (or "apps") for specific tasks. The memory may also be a virtual memory, which includes one or more memories distributed on multiple machines or devices coupled via a network.

[0033] Reference now Figure 1B , which is a diagram consistent with the embodiments of the present disclosure Figure 1A Schematic diagram of an exemplary wafer loading sequence in the charged particle beam inspection system 100 . Figure 1B is a two-dimensional view observed from the top of the inspection system 100. The X-axis and the Y-axis represent two perpendicular directions defining the projection plane. In some embodiments, the charged particle beam inspection system 100 may include a robot 11 located in the EFEM 30 and a robot 12 located in the main chamber 10. In some embodiments, the EFEM 30 may also include a pre-aligner 60 configured to accurately position the wafer before transporting the wafer to the load lock chamber 20.

[0034] In some embodiments, for example, the first load port 30a and the second load port 30b can accommodate a wafer front opening unified box (FOUP), which contains wafers. The robot 11 in the EFEM 30 can transport the wafer from any load port to the pre-aligner 60 to assist in positioning. The pre-aligner 60 can use mechanical or optical alignment methods to position the wafer. After pre-alignment, the robot 11 can transport one or more wafers to the load lock chamber 20 through the door 25.

[0035] After the wafer is transported to the load lock chamber 20, a load lock vacuum pump (not shown) can remove gas molecules in the load lock chamber 20 to reach a first pressure lower than atmospheric pressure. After reaching the first pressure, the door 26 connected between the load lock chamber and the main chamber is opened, and the robot 12 can transport the wafer from the load lock chamber 20 to the wafer stage 80 of the electron beam tool 40 in the main chamber 10. In some embodiments, the main chamber 10 can also be connected to a main chamber vacuum pump system (not shown), which can further remove gas molecules in the main chamber 10 to reach a second pressure lower than the first pressure. After reaching the final pressure, the wafer can be inspected by the electron beam tool.

[0036] After inspection, the wafer is transported back to the load lock chamber 20 which remains at the same vacuum level as the main chamber 10. Then, the door 26 is closed and gas is vented into the load lock chamber 20 to restore the pressure of the chamber to atmospheric level. When the pressure inside the load lock chamber 20 reaches atmospheric level, the door 25 is opened and the inspected wafer is exchanged with a new wafer.

[0037] In some embodiments, the main chamber 10 may include a parking station 70 configured to temporarily hold wafers before inspection. For example, when the inspection of the first wafer is completed, the first wafer can be unloaded from the wafer stage 80, and then the robotic arm 12 can transport the second wafer from the parking station 70 to the wafer stage 80. After that, the robotic arm 12 can transport the third wafer from the load lock chamber 20 to the parking station 70 to temporarily hold the third wafer until the inspection of the second wafer is completed. The parking station 70 can also be maintained in a high vacuum state.

[0038] Now refer to Figure 2 , which is a schematic diagram illustrating a load lock chamber 200 with a conventional configuration. In a conventional design, the top of the load lock chamber 200 is sealed by a flat top wall 210. Various tools and structures are placed on the flat top wall 210. For example, the load lock chamber 200 may have a vacuum port 280 connected to a pumping and pressure reducing structure 282, which may include a load lock roughing valve, a turbo molecular pump, and / or a load lock rough pump. The load lock chamber 200 may also include a vent port 260 connected to a venting structure 212, which may include a gas supply device and a vent valve. The load lock chamber 200 further includes a wafer stage 255 for holding the wafer 250 during pumping and pressure reducing and venting and pressure increasing operations.

[0039] In a conventional load lock chamber design, the vent port 260 is typically placed on the flat top wall 210, and thus the vented gas flows from top to bottom as shown by the arrow 291. Injecting gas from the top of the load lock chamber 20 can provide a strong downward gas flow inside the chamber, which enables a rapid venting and pressure increasing operation to obtain better system throughput. The downward vent gas flow also reduces the chance of disturbing contaminant particles that may be present on the inner surface of the bottom of the load lock chamber 20.

[0040] However, a downward gas flow requires a large baffle 240 to protect the wafer 250. For example, the baffle 240 is typically directly suspended below the vent 260 to prevent the high-speed downward gas flow from directly impinging on the surface of the wafer 250. Instead, the downward gas flow is redirected laterally, as shown by arrows 291-295. The high-speed impinging gas flow can also generate vortex gas flows and strong local flow separations, i.e., local reversals of the gas flow direction, as shown by arrows 292, 293, and 294. As shown by arrows 292, 293, and 294, these vortex gas flows and local flow separations propagate long distances on the surface of the baffle 240 with strong perturbation motions, which may stir up particles (not shown) along the way. The strong interfering gas flow and stirred-up particles may affect the wafer 250 and result in defects, reduced yield, and reduced inspection quality. Therefore, the baffle 240 in the load lock chamber 200 with the flat top wall 210 is typically very large to ensure that the vortices and local flow separations are sufficiently attenuated or eliminated before reaching the surface of the wafer 250 (as shown by arrows 292, 293, 294, and 295).

[0041] Installing a large baffle in the load lock chamber has drawbacks. First, in order to accommodate such a large baffle within the chamber, the load lock chamber needs to have a relatively large internal volume. However, a relatively large internal volume means that it takes longer to evacuate and pressurize the chamber, and thus reduces the overall throughput of the system. Second, if tools are mounted on the top wall of the load lock chamber, the large baffle can block the view of various tools of the wafer surface. For example, as Figure 2 shown, the load lock chamber 200 can include a sensor 285 on the top wall 210. The sensor 285 can include, but is not limited to, a laser-based wafer positioning sensor, an infrared sensor, a temperature sensor. The load lock chamber 200 can also have a vacuum qualifying tool 286 on the top wall 210, which includes, but is not limited to, a plasma cleaner and a residual gas analyzer. The sensor 285 and the vacuum qualifying tool 286 need an unobstructed direct line of sight to the surface of the wafer 250 to function properly. The large baffle 240 renders the sensor 285 and the vacuum qualifying tool 286 unavailable or at least limits their placement options. Finally, the large baffle may also reduce the efficiency of the evacuation operation. The load lock chamber can have a vacuum port 280 mounted on the top wall 210. As Figure 2 shown, the large baffle 240 blocks the opening of the vacuum port 280, and thus the pumping speed of a vacuum pump (not shown) may be limited.

[0042] Now refer to Figure 3A 、 Figure 3B and Figure 3C , which are schematic diagrams illustrating an exemplary load lock chamber 300 consistent with embodiments of the present disclosure.Figure 3A is a perspective view of the load lock chamber 300. The load lock chamber 300 may include a top wall 310 that is inclined with respect to a side view of the top wall 310, i.e., the top wall 310 is inclined downwardly towards the side walls of the load lock chamber 300. In some embodiments, the entire portion of the top wall 310 is inclined, while in other embodiments, only a portion of the top wall 310 is inclined such that it includes an inclined top section 311 and a flat top section 312. In some embodiments, the inclined top section 311 of the top wall 310 may be conical. The load lock chamber 300 may also include a vent 360 near the vertex point of the conical inclined top section 311. In some embodiments, the load lock chamber 300 may also include one or more spare ports 370. Some of the spare ports 370 may be placed within the inclined top section 311 but away from the vent 360. Although Figure 3A the inclined top section 311 of the top wall 310 is shown as conical, it should be understood that the top wall 310 may include various shapes, including but not limited to a pyramid shape. A pyramid may have three or more sides, depending on the base. For example, if the base is triangular, the pyramid has three sides; if the base is square, the pyramid has four sides; and so on. A pyramid becomes a cone as the number of sides of its base increases.

[0043] Figure 3B is Figure 3A a cross-sectional view of the load lock chamber 300. As described above, the inclined top wall 310 may include an inclined top section 311 and a flat top section 312. The vent 360 is installed near the vertex (i.e., the highest point) of the inclined top section 311. Although in Figures 3A - 3C the inclined top section 311 is illustrated as conical, it can be understood that different styles (e.g., pyramid) of inclined tops (e.g., Figure 4A and Figure 4B the load lock chamber 400 in Figure 2 may be used). The load lock chamber 300 may also include a wafer stage 355 configured to hold the wafer 350 during evacuation and venting operations. As described above with reference to Figure 2 , during the venting operation, gas is injected via the vent 360, which creates a strong downward gas flow inside the chamber. To protect the wafer 350 from the strong downward gas flow, a baffle 340 may be positioned (e.g., suspended) below the vent 360. For reasons explained below, the baffle 340 may be much smaller than the baffle 240 in Figure 2 .

[0044] Due to the inclined top wall, the space created by the inner surface of the inclined top section 311 and the upper surface of the baffle 340 narrows towards the edge of the baffle 340. In Figure 3BIn this case, the tapered space is shaded and labeled as 366. When gas is injected via vent 360, it diffuses through the tapered space 366 and exits into the rest of the chamber through the narrow opening 385 around the edge of baffle 340. Even if baffle 340 is much smaller, the tapered space 366 and the narrow opening 385 can effectively suppress the above-mentioned eddy currents and local separations. For example, as Figure 3B shown, a strong downward gas flow 391 can generate an eddy current 392. However, when the gas flow reaches the edge of baffle 340, the eddy current motion is sufficiently attenuated or eliminated, resulting in a smooth gas flow exiting through the narrow opening 385. Figure 3C illustrates the gas flow velocity in the chamber. The velocity of the gas flow is very high around vent 360. However, when the gas flows through the tapered space 366, its velocity rapidly decays, and when the gas flow reaches around the narrow opening 385, the velocity becomes quite low. Even if the gas moves downward and impacts the surface of wafer 350, this slow gas flow does not affect wafer 350.

[0045] Since the size of baffle 340 is greatly reduced compared to a flat top-loading lock chamber (such as the load lock chamber 200 in Figure 2 ), the upper part of load lock chamber 300 (e.g., the part above wafer 350) can also be made smaller, which reduces the internal volume of load lock chamber 300. In some embodiments, the volume reduction can be about 30% of the total internal volume, which can correspond to a reduction of about 30% in the time required for venting pressurization and pumping-down depressurization operations.

[0046] Furthermore, baffle 340 no longer covers the entire surface of wafer 350, but only covers the central part of wafer 350. Therefore, with the small baffle 340, the reserved port 370 on the inclined top wall 310 has a direct and unobstructed line of sight to the surface of wafer 350. Thus, various sensors (such as the sensor 285 in Figure 2 ) and vacuum tools (such as the vacuum-compatible tool 286 in Figure 2 ) can be connected to the reserved port 370. Similarly, a vacuum pump (e.g., a turbo molecular pump or a roughing pump) can be connected to one or more reserved ports 370, enabling a fast pumping-down depressurization speed without being blocked by a large baffle.

[0047] Now refer to Figure 4A and Figure 4B , which are schematic diagrams illustrating other exemplary configurations of a load lock chamber consistent with embodiments of the present disclosure. As Figure 4A shown, the top wall 410 can include a flat top surface 414 and an inclined inner surface 413. The flat top surface 414 can provide structural support for various tools that can be mounted on top of the load lock chamber, while in a manner consistent with Figures 3A - 3Coperates in the same manner and has the same benefits as the load lock chamber 300 with an inclined top wall as shown.

[0048] Figure 4B Another possible configuration of a load lock chamber with an inclined top wall of a different shape is shown. The top wall 410 can be inclined on only one side. For example, the top wall 410 can have a semi - conical shape. As Figure 4B shown, the vent 460 can be installed at the apex point position of the semi - conical shape. It should be understood that the top wall 410 can be of different shapes, such as a semi - pyramidal shape. The space created by the inclined inner surface 413 and the upper surface of the baffle 440 narrows towards the edge of the baffle 440, and thus, the strong downward gas flow can be mitigated in a similar manner as described above with respect to Figures 3A - 3C that which was explained.

[0049] The embodiments can be further described using the following sections:

[0050] 1. A vacuum chamber for a system configured to process wafers, comprising:

[0051] A top wall, wherein at least a portion of the inner surface of the top wall is inclined with respect to a side view of the top wall;

[0052] A vent, coupled to the top wall; and

[0053] A baffle, coupled to the vacuum chamber and positioned below the vent, wherein the baffle is configured to reduce the turbulence of the gas entering the vacuum chamber via the vent.

[0054] 2. The vacuum chamber according to section 1, further comprising a space created by the top wall and the baffle, wherein the space has a maximum height around the vent and narrows towards the edge of the baffle.

[0055] 3. The vacuum chamber according to section 1, wherein the vacuum chamber is configured to accommodate a wafer and hold the wafer on a wafer stage, wherein the baffle is configured to be located between the vent and the wafer when the wafer is held on the wafer stage.

[0056] 4. The vacuum chamber according to section 3, wherein the maximum width of the baffle is less than the diameter of the wafer.

[0057] 5. The vacuum chamber according to section 3, wherein the baffle has a substantially circular shape, and the diameter of the baffle is less than the diameter of the wafer.

[0058] 6. The vacuum chamber according to any one of paragraphs 2 to 5 further includes a sensor coupled to the top wall, wherein the sensor is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

[0059] 7. The vacuum chamber according to any one of paragraphs 2 to 6 further includes a vacuum tool coupled to the top wall, wherein the vacuum tool is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

[0060] 8. The vacuum chamber according to any one of paragraphs 1 to 7, wherein the inner surface of the top wall has a conical or pyramidal shape.

[0061] 9. The vacuum chamber according to any one of paragraphs 1 to 7, wherein the inner surface of the top wall has a semi - conical or semi - pyramidal shape.

[0062] 10. The vacuum chamber according to any one of paragraphs 1 to 9, wherein the vent is located at the vertex of the inner surface of the top wall.

[0063] 11. A vacuum chamber, comprising:

[0064] A top wall having an inner surface facing the interior of the vacuum chamber; and

[0065] A vent coupled to the top wall and configured to supply gas into the vacuum chamber;

[0066] wherein at least a portion of the inner surface of the top wall slopes downward at an angle from the location of the vent, and the vacuum chamber is configured to receive a wafer and hold the wafer on a wafer stage.

[0067] 12. The vacuum chamber according to paragraph 11 further includes a baffle coupled to the vacuum chamber and configured to be located between the vent and the wafer when the wafer is held on the wafer stage, wherein the baffle is configured to manipulate the flow of the gas supplied via the vent.

[0068] 13. The vacuum chamber according to paragraph 12 further includes a space created by the inner surface of the top wall and the upper surface of the baffle, wherein the space has a maximum height around the vent and narrows towards the edge of the baffle.

[0069] 14. The vacuum chamber according to paragraph 12, wherein the maximum width of the baffle is less than the diameter of the wafer.

[0070] 15. The vacuum chamber according to paragraph 12, wherein the baffle has a substantially circular shape and the diameter of the baffle is less than the diameter of the wafer.

[0071] 16. The vacuum chamber according to any one of paragraphs 11 to 15 further includes a sensor coupled to the top wall, wherein the sensor is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

[0072] 17. The vacuum chamber according to any one of paragraphs 11 to 16 further includes a vacuum tool coupled to the top wall, wherein the vacuum tool is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

[0073] 18. The vacuum chamber according to any one of paragraphs 11 to 17, wherein the inner surface of the top wall has a conical or pyramidal shape.

[0074] 19. The vacuum chamber according to any one of paragraphs 11 to 17, wherein the inner surface of the top wall has a semi - conical or semi - pyramidal shape.

[0075] 20. The vacuum chamber according to any one of paragraphs 1 to 19, wherein the vent is located at the apex of the inner surface of the top wall.

[0076] Although the disclosed embodiments have been explained in connection with the preferred embodiments, it should be understood that other modifications and variations can be made without departing from the spirit and scope of the subject matter claimed hereinafter.

Claims

1. A vacuum chamber for a system configured to process wafers, comprising: A top wall, wherein at least a portion of the inner surface of the top wall is inclined with respect to a side view of the top wall; A vent, coupled to the top wall; And A baffle, coupled to the vacuum chamber and positioned below the vent, wherein the baffle is configured to reduce turbulence of gas entering the vacuum chamber via the vent.

2. The vacuum chamber according to claim 1, further comprising a space created by the top wall and the baffle, wherein the space has a maximum height around the vent and narrows towards an edge of the baffle.

3. The vacuum chamber according to claim 1, wherein the vacuum chamber is configured to accommodate a wafer and hold the wafer on a wafer stage, and wherein the baffle is configured to be positioned between the vent and the wafer when the wafer is held on the wafer stage.

4. The vacuum chamber according to claim 3, wherein a maximum width of the baffle is less than a diameter of the wafer.

5. The vacuum chamber according to claim 3, wherein the baffle has a substantially circular shape, and a diameter of the baffle is less than the diameter of the wafer.

6. The vacuum chamber according to claim 2, further comprising a sensor coupled to the top wall, wherein the sensor is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

7. The vacuum chamber according to claim 2, further comprising a vacuum tool coupled to the top wall, wherein the vacuum tool is positioned to have a direct line of sight to the wafer when the wafer is held on the wafer stage.

8. The vacuum chamber according to claim 1, wherein the inner surface of the top wall has a conical or pyramidal shape.

9. The vacuum chamber according to claim 1, wherein the inner surface of the top wall has a semi - conical or semi - pyramidal shape.

10. The vacuum chamber according to claim 1, wherein the vent is located at a vertex of the inner surface of the top wall.

11. A vacuum chamber, comprising: A top wall having an inner surface facing the interior of the vacuum chamber; And A vent, coupled to the top wall and configured to supply gas into the vacuum chamber; Wherein at least a portion of the inner surface of the top wall is inclined at a downward angle from a position of the vent, and the vacuum chamber is configured to accommodate a wafer and hold the wafer on a wafer stage.

12. The vacuum chamber according to claim 11, further comprising a baffle, the baffle being coupled to the vacuum chamber and configured to be located between the vent and the wafer when the wafer is held on the wafer stage, wherein the baffle is configured to manipulate a flow of the gas supplied via the vent.

13. The vacuum chamber according to claim 12, further comprising a space created by the inner surface of the top wall and an upper surface of the baffle, wherein the space has a maximum height around the vent and narrows towards an edge of the baffle.

14. The vacuum chamber according to claim 12, wherein a maximum width of the baffle is less than a diameter of the wafer.

15. The vacuum chamber according to claim 12, wherein the baffle has a substantially circular shape and the diameter of the baffle is smaller than the diameter of the wafer.

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