Purging in load lock chambers

Abstract

A method for removing residues from the surface of a wafer located in a load-locked chamber or removing contaminants from inside the load-locked chamber via a purging process is disclosed. The disclosed system includes a load-locked chamber, an injection system configured to supply purge gas into the load-locked chamber, an exhaust system configured to remove gas from the load-locked chamber, and a controller. The controller can remove contaminants and / or residues from the load-locked chamber by: controlling the injection system to supply purge gas inside the load-locked chamber to increase the chamber pressure; controlling the exhaust system to remove gas from the load-locked chamber and decrease the chamber pressure; and then controlling the injection system to supply purge gas inside the load-locked chamber and increase the chamber pressure.

Description

Technical Field

[0001] This disclosure generally relates to the field of semiconductor processing methods and systems, and more specifically to the field of device and integrated circuit manufacturing. More specifically, this disclosure generally relates to purging or removing contaminants from a load-locked chamber. Background Technology

[0002] In semiconductor manufacturing, wafers undergo various processing steps, which may leave residual process gases, fragments, and byproducts on the wafer surface. When the wafer is subsequently transferred to a load-locking chamber, these residues on the wafer surface may detach. This detached residue or contaminant may adhere to the inner walls of the load-locking chamber and / or other components in fluid communication with the load-locking chamber, thereby corroding or damaging the inner walls and / or components. Therefore, it is desirable to remove the detached residue or contaminant to prevent corrosion or damage to the load-locking chamber without compromising its function and lifespan. Such damage to the load-locking chamber due to contamination can lead to costly maintenance and potential downtime.

[0003] When a wafer is present in a processing chamber, residues or contaminants can be removed by running one or more purge cycles within the chamber. A purge cycle typically involves introducing a purge gas that helps remove residues from the wafer surface. However, processing chambers are characterized by their large volume. Therefore, the time required to remove residues can be quite long, which can impact the overall yield of the semiconductor manufacturing process, slowing down production and affecting operational efficiency.

[0004] Any discussion set forth in this section (including discussions of problems and solutions) is included in this disclosure for the purpose of providing background information and should not be construed as an admission that any or all of the discussions were known at the time of making this invention or otherwise constitute prior art. Summary of the Invention

[0005] This invention provides a simplified overview of some concepts, which will be described in further detail below. This invention is not intended to require the identification of key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0006] Various embodiments of this disclosure relate to removing residues from the wafer surface by transferring the wafer to a load-locked chamber and performing a purging process inside the load-locked chamber to remove residues from the wafer surface or any contaminants discharged from the load-locked chamber.

[0007] According to an example of this disclosure, a load-locking module may include: a load-locking chamber; at least one wafer holder configured to support a wafer in the load-locking chamber; an injection system coupled to the load-locking chamber and configured to provide purge gas into the load-locking chamber; an exhaust system coupled to the load-locking chamber and configured to remove gas from the load-locking chamber; and a controller. The controller may be a system for providing purge gas inside the load-locking chamber to increase the chamber pressure inside the load-locking chamber to a first level. The controller may then control the exhaust system to remove gas from the load-locking chamber, causing the chamber pressure to decrease from the first level to a second level, and then control the injection system to provide purge gas inside the load-locking chamber, causing the chamber pressure to increase from the second level to a third level.

[0008] According to examples of this disclosure, the venting system may include a first vent valve and a second vent valve, wherein the second vent valve can remove gas from the load-locked chamber at a faster rate than the first vent valve. According to examples of this disclosure, a controller may be configured to control the venting system to remove gas from the load-locked chamber by: opening the first vent valve during a first time period to reduce the chamber pressure from a first level to an intermediate level; closing the first vent valve; opening the second vent valve during a second time period to reduce the chamber pressure from the intermediate level to a second level; and closing the second vent valve. According to examples of this disclosure, the second time period may be longer than the first time period. According to examples of this disclosure, the controller may also be configured to control the injection system to provide purge gas or inert gas inside the load-locked chamber during a portion of the first or second time period.

[0009] According to examples of this disclosure, the injection system may include a first injection valve and a second injection valve, wherein the second injection valve supplies gas to the load-locked chamber at a faster rate than the first injection valve. In some embodiments, the injection system further includes a mass flow controller connected in series with the first injection valve. According to examples of this disclosure, the controller may be configured to control the injection system to supply purge gas inside the load-locked chamber, such that opening the first injection valve increases the chamber pressure to a first level or a third level. After the chamber pressure reaches an intermediate level, the controller may open the second injection valve to increase the chamber pressure from the intermediate level to the first or third level. After the chamber pressure reaches the first or third level, the controller may close both the first and second injection valves.

[0010] According to examples of this disclosure, the first level of chamber pressure in the load-locked chamber can be substantially equal to the third level, and the second level is lower than the first and third levels.

[0011] According to examples of this disclosure, the controller may be further configured to control the exhaust system to remove gas from the load-locked chamber after the chamber pressure increases from the second level to the third level.

[0012] According to examples of this disclosure, the load-locking module may further include a first gate valve coupled to the load-locking chamber and configured to allow wafer transfer between the load-locking chamber and the Equipment Front-End Module (EFEM). The controller may be configured to keep the first gate valve closed while removing contaminants from the load-locking chamber.

[0013] According to examples of this disclosure, the load-locking module may include a second gate valve coupled to the load-locking chamber and configured to allow the transfer of a wafer between the load-locking chamber and the wafer transport chamber. Before removing contaminants from the load-locking chamber, the controller may be configured to set the second gate valve to an open state and transfer the wafer from the wafer transport chamber to the load-locking chamber.

[0014] According to examples in this disclosure, the purging gas may include molecular nitrogen, argon, or helium.

[0015] According to an example of this disclosure, a method for removing contaminants from a load-locked chamber may include providing a wafer inside the load-locked chamber, providing a purge gas inside the load-locked chamber to increase the chamber pressure inside the load-locked chamber to a first level, removing the gas from the load-locked chamber to decrease the chamber pressure from the first level to a second level, and providing a purge gas inside the load-locked chamber to increase the chamber pressure from the second level to a third level.

[0016] According to examples of this disclosure, removing gas from a load-locked chamber may include opening a first vent valve during a first time period to reduce the chamber pressure from a first level to an intermediate level, closing the first vent valve, opening a second vent valve during a second time period to reduce the chamber pressure from the intermediate level to a second level, and closing the second vent valve. The second vent valve may remove gas from the load-locked chamber at a faster rate than the first vent valve. According to examples of this disclosure, the second time period may be longer than the first time period. According to examples of this disclosure, removing gas from the load-locked chamber may also include providing purge gas or inert gas inside the load-locked chamber during a portion of the first or second time period.

[0017] According to examples of this disclosure, providing purge gas inside the load-locked chamber to increase the chamber pressure to a first or third level may include opening a first injection valve. After the chamber pressure reaches an intermediate level, a second injection valve may be opened to increase the chamber pressure from the intermediate level to the first or third level, and after the chamber pressure reaches the first or third level, both the first and second injection valves may be closed.

[0018] According to examples of this disclosure, the method may also include removing gas from the load-locked chamber after the chamber pressure increases from a second level to a third level.

[0019] According to examples of this disclosure, the method may further include: keeping a first gate valve closed while removing contaminants from the load-locked chamber, the first gate valve being coupled to the load-locked chamber and configured to allow the transfer of a wafer between the load-locked chamber and the device front-end module (EFEM).

[0020] According to an example of this disclosure, providing a wafer inside a load-locked chamber may include setting a second gate valve coupled to the load-locked chamber to an open state, transferring the wafer from a wafer transport chamber to the load-locked chamber through the open second gate valve, and setting the second gate valve to a closed state.

[0021] For the purpose of summarizing the invention and its advantages relative to the prior art, certain objects and advantages of the invention have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the invention. Therefore, for example, those skilled in the art will recognize that the invention may be embodied or implemented in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0022] All these embodiments are intended to fall within the scope of the invention disclosed herein. Those skilled in the art will readily appreciate these and other embodiments from the following detailed description of certain embodiments with reference to the accompanying drawings; however, the invention is not limited to any particular embodiment disclosed. Attached Figure Description

[0023] To facilitate identification of any particular element or action being discussed, one or more of the most significant digits in the reference numerals refer to the drawing number in which the element was first introduced.

[0024] Embodiments of this disclosure can be more fully understood when considered in conjunction with the following illustrative drawings, and by referring to the detailed description and claims.

[0025] Figure 1A An example wafer processing apparatus according to one or more embodiments of the present disclosure is shown.

[0026] Figure 1B Another example wafer processing apparatus according to one or more embodiments of the present disclosure is shown.

[0027] Figure 2 An example load locking module according to one or more embodiments of the present disclosure is shown.

[0028] Figure 3 This is a flowchart illustrating an example of a method for purging a load-locked chamber according to one or more embodiments of the present disclosure.

[0029] Figure 4AThe illustration shows one or more embodiments according to this disclosure. Figure 3 Example of how chamber pressure in the load-locked chamber changes over time during each stage of the example method.

[0030] Figure 4B The illustration shows one or more embodiments according to this disclosure. Figure 3 Example states of different components of the load-locking chamber during each stage of the example method.

[0031] Figure 5 This is a flowchart illustrating another exemplary method of purging a load-locked chamber according to one or more embodiments of the present disclosure.

[0032] Figure 6A The illustration shows one or more embodiments according to this disclosure. Figure 5 Example of how chamber pressure in the load-locked chamber changes over time during each stage of the example method.

[0033] Figure 6B The illustration shows one or more embodiments according to this disclosure. Figure 5 Example states of different components of the load-locking chamber during each stage of the example method.

[0034] Figure 7A A functional block diagram of a controller according to one or more embodiments of the present disclosure is shown.

[0035] Figure 7B The processing circuitry of a controller according to one or more embodiments of the present disclosure is shown.

[0036] It should be understood that the elements in the accompanying drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements to aid in understanding the embodiments shown in this disclosure. Detailed Implementation

[0037] The following description of exemplary embodiments of the methods and compositions is merely illustrative and for purposes of explanation only. The following description is not intended to limit the scope of this disclosure or the claims. Furthermore, the description of multiple embodiments having indicated features or steps is not intended to exclude other embodiments having additional features or steps or other embodiments including different combinations of said features or steps.

[0038] As used herein, the term "wafer" can refer to any underlying material that can be used to form or on which devices, circuits, or films can be formed using methods according to embodiments of the invention. A wafer may comprise a bulk material, such as silicon (e.g., single-crystal silicon), other group IV materials (e.g., germanium), or other semiconductor materials (e.g., group II-VI or III-V semiconductor materials), and may comprise one or more layers overlying or underlying the bulk material. A wafer may include various topologies, such as gaps, including recesses, lines, trenches, or spaces between raised portions (e.g., fins) formed within or on at least a portion of the layers of the wafer. By way of example, a wafer may comprise a bulk semiconductor material and an insulating or dielectric material layer covering at least a portion of the bulk semiconductor material. Furthermore, the term "wafer" can refer to any one or more underlying materials that can be used or on which devices, circuits, or films can be formed. A "wafer" can be continuous or discontinuous; rigid or flexible; solid or porous. A "wafer" can be in any form, such as powder, plate, or workpiece. Plate-type wafers can include wafers of various shapes and sizes. For example, the wafer can be made of materials such as silicon, silicon germanium, silicon oxide, gallium arsenide, gallium nitride, and silicon carbide. A continuous wafer can extend beyond the boundary of the processing chamber where the deposition process takes place and can move through the processing chamber, allowing the process to continue until the end of the wafer is reached. Continuous wafers can be supplied from a continuous wafer feed system, allowing continuous wafers to be manufactured and output in any suitable form. Non-limiting examples of continuous wafers may include sheets, nonwoven films, rolls, foils, meshes, flexible materials, or bundles of continuous filaments or fibers (i.e., ceramic fibers or polymer fibers). Continuous wafers may also include a carrier or sheet on which non-continuous wafers are mounted.

[0039] As used herein, the term "layer" can refer to any continuous or discontinuous structure and material. For example, a layer can include two-dimensional materials, three-dimensional materials, nanoparticles, or even partial or complete molecular layers or partial or complete atomic layers or atomic and / or molecular clusters. A layer can include a material or layer with pinholes, which can be at least partially continuous.

[0040] The term "atomic layer deposition" can refer to a vapor phase deposition process in which deposition cycles, typically multiple consecutive deposition cycles, are performed in a processing chamber. As used herein, the term atomic layer deposition is also intended to include processes specified by related terms such as chemical vapor deposition, atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas-source MBE, organometallic MBE, and chemical beam epitaxy when performed using alternating pulses of precursor / reactive gases and purge gases (e.g., inert carrier gases).

[0041] Typically, for an ALD process, during each deposition cycle, a precursor is introduced into the reaction chamber and chemisorbed onto the deposition surface (e.g., the wafer surface may include previously deposited material from a previous ALD cycle or other materials), forming a monolayer or submonolayer material that does not readily react with further precursors (i.e., a self-limiting reaction). Subsequently, in some cases, a reactant (e.g., another precursor or reactive gas) may be introduced into the processing chamber to convert the chemisorbed precursor into the desired material on the deposition surface. The reactant is capable of further reacting with the precursor. During one or more deposition cycles, such as during each step of each cycle, a purging step may be used to remove any excess precursor from the processing chamber and / or any excess reactant and / or reaction byproducts from the reaction chamber.

[0042] In this disclosure, any two numbers of a variable may constitute a feasible range of the variable, and any range indicated may include or exclude endpoints. Furthermore, any value of the indicated variable (whether or not it is indicated by “about”) may refer to an exact value or an approximate value and includes equivalents, and in some embodiments may refer to an average, median, representative value, multi-value, etc. Additionally, in this disclosure, the terms “comprising,” “consisting of,” and “having” may, in some embodiments, independently mean “generally or broadly comprising,” “including,” “substantially consisting of,” or “consisting of.” The meaning of any definition in this disclosure does not necessarily exclude the common and customary meaning in some embodiments. In some cases, percentages indicated herein may be relative or absolute percentages.

[0043] Numerous example materials are given throughout the embodiments of this disclosure. It should be noted that the chemical formulas given for each example material should not be interpreted as limiting, and the non-limiting example materials given should not be limited by the given example stoichiometry.

[0044] In this specification, it will be understood that the terms "on" or "above" may be used to describe relative positional relationships. Another element, film, or layer may be directly on the mentioned layer, or another layer (intermediate layer) or element may be inserted therebetween, or a layer may be disposed on the mentioned layer but not completely cover the surface of the mentioned layer. Therefore, unless the term "directly" is used alone, the terms "on" or "above" will be interpreted as relative concepts. Similarly, it will be understood that the terms "below," "under," or "beneath" will be interpreted as relative concepts.

[0045] When wafers are handled during semiconductor device manufacturing, residues (such as residual process gases, fragments, and byproducts) may remain on the wafer surface as a result of the process. These residues can cause various types of contamination. First, self-contamination can occur when residues on the wafer react with the atmosphere and damage the wafer itself (e.g., crystal defects, mask etching, or pattern collapse). Equipment contamination can occur when residues on the wafer react with moisture in the atmosphere and cause degassing, which may transfer to wafer handling equipment (e.g., robotic arms used to transfer wafers) or components and / or inner walls of the load-locking chamber. These residues or contaminants can then cause corrosive damage to the equipment over time.

[0046] This document describes a process for removing residues and / or contaminants from the surface of a wafer located in a load-lock chamber and / or from inside the load-lock chamber. Residues or contaminants can be removed via a purging process within the load-lock chamber. Removing residues and / or contaminants from the load-lock chamber prevents corrosion and / or damage to the load-lock chamber. Furthermore, residues on the wafer surface can be removed, preparing the wafer for the next stage of the semiconductor manufacturing process.

[0047] One of the significant advantages of performing the purging process in a load-locked chamber rather than a processing chamber is the smaller chamber volume compared to the processing chamber. The relatively smaller size of the load-locked chamber offers several benefits, contributing to improved efficiency in semiconductor manufacturing processes. For example, the smaller volume of the load-locked chamber allows for faster purging cycles, which helps minimize delays between steps throughout the semiconductor manufacturing process, resulting in better system yield and operational efficiency. With a smaller volume to manage inside the load-locked chamber, the purging gas can more effectively and quickly remove any residual escaping gases from the wafer. Faster and more efficient removal of residues and / or contaminants reduces the likelihood of material degradation or corrosion inside the load-locked chamber, thereby improving the lifespan and reliability of the load-locked module.

[0048] Now turn to the attached image. Figure 1A This is a diagram illustrating an example configuration of a wafer processing apparatus 10. The wafer processing apparatus 10 may include multiple load ports. Figure 1AIn the example, there are three load ports, namely load ports 12, 14, and 16. The number of load ports in the wafer processing apparatus 10 is set to three, but there may be two, four, or more load ports. The front-end module 18 may be arranged adjacent to multiple load ports 12, 14, and 16. The front-end module 18 includes a fan filter unit (FFU) which may be configured to transfer wafers at atmospheric pressure. The front-end module 18 may include a first wafer transfer device 19. According to one example, the first wafer transfer device 19 may be a robot for transferring wafers. Load ports 12, 14, and 16, the front-end module 18, and the first wafer transfer device 19 may be collectively referred to as a device front-end module (EFEM) or housing.

[0049] A first load-locking chamber (first LLC) 20 and a second load-locking chamber (second LLC) 30 can be disposed adjacent to the front-end module 18. The first LLC 20 and the second LLC 30 can be connected to a vacuum device and can be set to atmospheric pressure or vacuum. According to one example, the first LLC 20 and the second LLC 30 can be two independent chambers, preventing gas from moving from one chamber to the other. For informational purposes, in Figure 1A The system provides two load-locking chambers, but can provide three or more load-locking chambers. Gate valve 22 can be located between the first LLC 20 and the front-end module (FEM) 18. Gate valve 32 can be located between the second LLC 30 and the FEM 18.

[0050] A wafer transfer chamber (WHC) 40 may be positioned adjacent to a load locking module including a first LLC 20 and a second LLC 30. A second wafer transfer device 41 may be present in the WHC 40. According to one example, the second wafer transfer device 41 may be a robot for transferring wafers. A gate valve 24 may be disposed between the first LLC 20 and the WHC 40. A gate valve 34 may be disposed between the second LLC 30 and the WHC 40. Processing chambers 42, 44, 46, and 48 may be adjacent to the WHC 40 via gate valves 42a, 44a, 46a, and 48a, respectively.

[0051] WHC40 can contact WHC60 via a through chamber 50. According to one example, the through chamber 50 may include an upper through chamber with a gate valve on the WHC60 side and a lower through chamber with a gate valve on the WHC40 side. In other words, a gate valve may exist between WHC40 and WHC60 in both the upper and lower through chambers. This allows the pressures of WHC40 and WHC60 to be different from each other. A third wafer transfer device 62 may be disposed within WHC60. According to one example, each of the second wafer transfer device 41 and the third wafer transfer device 62 may have two vertically arranged arms. According to another example, the number of arms can be any number.

[0052] Processing chambers 64, 66, 68, and 70 may be adjacent to WHC60 via gate valves 64a, 66a, 68a, and 70a, respectively. According to one example, processing chambers 42, 44, 46, and 48, and processing chambers 64, 66, 68, and 70, may be configured as apparatus for forming epitaxial growth films on a wafer through single-wafer processing, such as by chemical vapor deposition (CVD), atomic layer epitaxy (ALE), molecular beam epitaxy (MBE), gas-source MBE, organometallic MBE, or chemical beam epitaxy. Layers can be grown on the wafer by providing alternating pulses of precursor / reactive gas and purge gas (e.g., inert carrier gas) in the reactor chamber.

[0053] The controller 28 can control the transport and processing of wafers in the wafer processing apparatus 10. According to one example, the controller 28 manages a job list, issues commands for transporting wafers, and issues commands for processing wafers. As information, wafers can be transported along a transport path already specified by the control job.

[0054] Figure 1A The wafer processing apparatus 10 can be configured differently. According to one example, the through chamber 50, WHC 60, and processing chambers 64, 66, 68, and 70 can be omitted. According to another example, the processing chambers for single-wafer processing can be replaced by a dual-chamber module (DCM) or a quad-chamber module (QCM), or by another batch processing chamber.

[0055] Figure 1B An example of another wafer processing apparatus 90 is shown. The wafer processing apparatus 90 may include four DCMs 96 that are in contact with the WHC 40 and have two chambers. The wafer processing apparatus 90 may also include a load locking chamber 98, which includes one or more wafer supports to support the wafer.

[0056] Figure 2 A more detailed side view of an exemplary load-locking module 200 is shown, including a load-locking chamber 202 (e.g., load-locking chamber 20, 30, or 98) and associated components. The load-locking chamber 202 may include a wafer holder 208 configured to support a wafer 210. Residue 212 may adhere to the surface of the wafer 210. Some of the residue 212 may detach from the surface of the wafer 210 and adhere to the inner walls of the load-locking chamber 202, gate valves 214 and 216, and / or other components connected to the load-locking chamber 202. The detached residue may corrode the inner walls, gate valves, and / or components of the load-locking chamber 202. Residue remaining on the wafer may damage the wafer itself.

[0057] The load lock chamber 202 may also include or be connected to a gate valve 216 (e.g., gate valve 24 or 34). When the gate valve 216 is open, there may be fluid communication between the load lock chamber 202 and WHC 204 (e.g., WHC 40). When the gate valve 216 is closed, there is no fluid communication between the load lock chamber 202 and WHC 204. When the gate valve 216 is open, a wafer can be transferred from the processing chamber (e.g., processing chambers 42, 44, 46, 48, 64, 66, 68, or 70), WHC 40, or WHC 60 to the load lock chamber 202. Additionally, when the gate valve 216 is open, a wafer can be transferred from the load lock chamber 202 to the processing chamber (e.g., processing chambers 42, 44, 46, 48, 64, 66, 68, or 70), WHC 40, or WHC 60.

[0058] The load lock chamber 202 may also include or be coupled to another gate valve 214 (e.g., gate valve 22 or 32). When gate valve 214 is open, fluid communication may exist between the load lock chamber 202 and the front-end module 206 (e.g., front-end module 18). When gate valve 214 is closed, there is no fluid communication between the load lock chamber 202 and the front-end module 206. When gate valve 214 is open, a wafer can be transferred from the front-end module 206 or a load port (e.g., load port 12, 14, or 16) to the load lock chamber 202. Additionally, when gate valve 214 is open, a wafer can be transferred from the load lock chamber 202 to the front-end module 206 or a load port.

[0059] Furthermore, the load-locked chamber 202 can be coupled to an exhaust system 220, which is configured to remove gas from the load-locked chamber 202. The exhaust system 220 includes a dry pump 226 connected to the load-locked chamber 202 via both a slow exhaust valve 222 and a fast exhaust valve 224. The purging process inside the load-locked chamber 202 may require pressure variations between relatively high and relatively low pressures within the chamber. When evacuating the load-locked chamber 202 from a relatively high pressure to a relatively low pressure, the evacuation rate is preferably not large enough to cause undesirable turbulence (which could agitate particles within or attached to the pipe network of the load-locked chamber 202). Such turbulence or agitation of particles is undesirable because these events can contaminate or otherwise adversely affect the quality of the wafer 210. To avoid such undesirable turbulence, the processing chamber evacuation can typically occur in two steps. First, evacuation can be initiated by opening the slow exhaust valve 222, which includes a small orifice valve. The small opening of the slow exhaust valve 222 limits the rate at which gas can exit the load lock chamber 202. Slowly removing gas via the slow exhaust valve 222 helps minimize gas turbulence and particle agitation in the wafer 210. After pumping for a period of time through the slow exhaust valve 222 or after reaching a specific chamber pressure, the fast exhaust valve 224, which includes a larger opening, is opened to complete the evacuation. In some examples, the gas flow rate at the slow exhaust valve 222 can be from 0.1 to 15 slm, while the gas flow rate at the fast exhaust valve 224 can be from 15 to 50 slm.

[0060] The load lock chamber 202 may be further coupled to the injection system 230, which injects purge gas into the load lock chamber 202. The purge gas may be provided by a purge gas source 236. An exemplary purge gas source 236 may include one or more separate gas canisters, including nitrogen, argon, helium, carbon dioxide, and / or other inert gases. The purge gas source 236 may be coupled to the load lock chamber 202 via two valves (slow injection valve 232 and fast injection valve 234). In some embodiments, the purge gas source 236 may be coupled to the load lock chamber 202 via a first path 231 and a second path 233 in parallel. In some embodiments, the first path includes the slow injection valve 232. In some embodiments, the second path 233 includes the fast injection valve 234. In some embodiments, the first path may also include a mass flow controller 235 connected in series with the slow injection valve 232. In some embodiments, the mass flow controller 235 is located upstream of the slow injection valve 232. The mass flow controller 235 may be any suitable device capable of measuring and / or controlling the gas flow rate in the first path 231. The mass flow controller can be a thermal mass flow controller, an ultrasonic mass flow controller, a Coriolis mass flow controller, etc. When pumping the load-locked chamber 202 from a relatively low pressure to a relatively high pressure, the pumping rate is preferably not large enough to cause undesirable turbulence. Therefore, the pumping process in the load-locked chamber can occur in two steps, similar to the evacuation process described above. First, the pumping process can be started by opening the mass flow controller 235 and / or the slow injection valve 232, which includes a small orifice valve. The small size of the opening of the slow injection valve 232 limits the rate at which gas can enter the load-locked chamber 202. After gas has been pumped into the load-locked chamber 202 for a period of time via the slow injection valve 232 and / or the mass flow controller 235, or after a specific chamber pressure has been reached, the fast injection valve 234, which includes a larger opening valve, is opened to complete the backfilling of the load-locked chamber 202 with purge gas. In some examples, the gas flow rate at the slow injection valve 232 can be 0.1 to 15 slm, while the gas flow rate at the fast injection valve 234 can be 15 to 50 slm.

[0061] A chamber pressure sensor 240 can be coupled to the load-locked chamber 202 and configured to measure the pressure inside the load-locked chamber 202. A controller 250 is shown connected to the pressure sensor 240, an exhaust system 220 (e.g., connected to a slow exhaust valve 222 and a fast exhaust valve 224), an injection system 230 (e.g., connected to a slow injection valve 232, a mass flow controller 235, and / or a fast injection valve 234), and gate valves 214 and / or 216. The controller 250 can be configured to open and close gate valves 214 and / or 216, open or close slow exhaust valves 222 and / or fast exhaust valves 224 to remove gas from the load-locked chamber 202, and open or close one or more of the slow injection valves 232, mass flow controller 235, and fast injection valve 234 to provide purge gas inside the load-locked chamber 202. The controller can be configured to perform... Figure 3 and Figure 5 The method described below.

[0062] Figure 3 A flowchart 300 is shown illustrating an example method of purging a load-locked chamber (e.g., load-locked chamber 202) according to one or more embodiments of the present disclosure. The steps in flowchart 300 may be performed by a controller (e.g., controller 28 or 250) coupled to the load-locked chamber or by a wafer processing apparatus (e.g., wafer processing apparatus 10 or 20) carrying the load-locked chamber.

[0063] In step 302 of flowchart 300, a first gate valve (e.g., gate valve 214) may be closed between the load-locking chamber and a front-end module (e.g., front-end module 18 or 206) adjacent to the load-locking chamber. In step 304, a second gate valve (e.g., gate valve 216) may be opened between the load-locking chamber and a wafer transport chamber (e.g., wafer transport chamber 40 or 204) adjacent to the load-locking chamber. In step 306, a wafer may be transferred from the wafer transport chamber to the load-locking chamber via the opened gate valve. The wafer may be deposited in a wafer holder (e.g., wafer holder 208) inside the load-locking chamber. After the wafer is provided inside the load-locking chamber in step 306, the second gate valve may be closed in step 308. After the second gate valve is closed, the chamber pressure inside the load-locking chamber may be at the same level or substantially the same level as the pressure inside the wafer transport chamber. For example, Figure 4A An example of how the chamber pressure in the load-locked chamber changes over time is shown, while Figure 4B Example states of different components of the load lock chamber are shown. During time period A, after the wafer is transferred to the load lock chamber and after the second gate valve is closed, the chamber pressure inside the load lock chamber may be at the initial level 402 (e.g., the chamber pressure level of the wafer transport chamber).

[0064] Return to reference Figure 3In step 310, purge gas can be supplied to the load-locking chamber, causing the chamber pressure inside the load-locking chamber to increase from the initial level to a first level. For example, as... Figure 4A As shown, during time periods B and C, the chamber pressure increases from the initial level 402 to the first level 404. Supplying purge gas to the load-locked chamber may include opening one or more of a slow injection valve (e.g., slow injection valve 232), a mass flow controller (e.g., mass flow controller 235), and a fast injection valve (e.g., fast injection valve 234). For example, as... Figure 4B As shown, during time period B, the slow injection valve and / or mass flow controller can be opened. At the end of time period B, the chamber pressure inside the load-locked chamber can be at a cross level. After the chamber pressure crosses the cross level, time period C can begin, during which the fast injection valve can be opened, while the slow injection valve and / or mass flow controller remain open. Alternatively, the fast injection valve can be opened at the beginning of time period C, regardless of whether the chamber pressure inside the load-locked chamber has crossed the cross level. The slow injection valve can have a flow rate of 0.1-50 slm, while the fast injection valve can have a flow rate of 50-1000 slm. At the end of time period C, both the slow injection valve and / or mass flow controller and the fast injection valve can be closed.

[0065] Return to reference Figure 3 In step 312, gas can be removed from the load-locked chamber, causing the chamber pressure within the load-locked chamber to decrease from a first level to a second level. For example, as... Figure 4A As shown, during time periods D, E, and F, the chamber pressure decreases from a first level 404 to a second level 410. Removing gas from the load-locked chamber may include opening a slow vent valve (e.g., slow vent valve 222), a fast vent valve (e.g., fast vent valve 224), or both. For example, as... Figure 4BAs shown, during time period D, the slow vent valve can be opened. Time period D can be 1 to 20 seconds long. During time period D, the slow injection valve and / or mass flow controller can also be opened to allow a purge gas flow rate of 0.1 to 10 slm (e.g., nitrogen, argon, helium, or carbon dioxide). At the end of time period D, the chamber pressure inside the load-locked chamber can be at a first intermediate level 406. After the chamber pressure crosses the first intermediate level 406, time period E can begin, during which the fast vent valve can be opened while the slow vent valve remains open. Alternatively, the fast vent valve can be opened at the beginning of time period E regardless of whether the chamber pressure inside the load-locked chamber has crossed the first intermediate level 406. Time period E can be 1 to 10 seconds long. During time period E, the slow injection valve and / or mass flow controller can also be opened to allow a purge gas flow rate of 0.1 to 10 slm inside the load-locked chamber. At the end of time period E, the chamber pressure inside the load-locked chamber can be at a second intermediate level 408, such that the fast vent valve remains open at the beginning of time period F. Conversely, the slow vent valve can be closed during time period F. Time period F can be from 0.1 to 10 seconds. During time period F, the slow injection valve and / or mass flow controller can be closed. When removing gas from the load lock chamber, the slow vent valve can have a flow rate of 1-500 L / min, while the fast vent valve can have a flow rate of 500-20000 L / min. At the end of time period F, both the slow and fast vent valves can be closed, and the gas pressure can reach the second level 410.

[0066] Return to reference Figure 3 Steps 310 and 312 can constitute a purging cycle. In step 314, it can be determined whether the purging cycle needs to be repeated. If another purging cycle is needed, the method can continue to step 310. For example, as... Figure 4A As shown, during time periods G and H, the chamber pressure increases from the second level 410 to the third level 412. The third level can be substantially the same as or different from the first level 404 (e.g., higher or lower). The chamber pressure can be increased to the third level 412 by opening and closing the slow injection valve and / or mass flow controller, as well as the fast injection valve, in the same sequence performed during time periods B and C. (Return to Reference) Figure 3 In step 314, if it is determined that no further purge cycles are needed, the method ends.

[0067] Figure 5This is a flowchart illustrating another example method of purging a load-locked chamber (e.g., load-locked chamber 202) according to one or more embodiments of the present disclosure. The steps in flowchart 500 may be performed by a controller (e.g., controller 28 or 250) coupled to the load-locked chamber or by a wafer processing apparatus (e.g., wafer processing apparatus 10 or 20) carrying the load-locked chamber.

[0068] Steps 502, 504, 506, and 508 of flowchart 500 can be similar to Figure 3 Steps 302, 304, 306, and 308 of flowchart 300 are referenced here; therefore, details of steps 502, 504, 506, and 508 of flowchart 500 are omitted here. After both the first and second gate valves are closed, the chamber pressure inside the load locking chamber can be at the same level or substantially the same level as the pressure inside the wafer transport chamber. For example, Figure 6A Example variations of chamber pressure over time in the load-locking chamber are shown during different steps of flowchart 500, while Figure 6B Example states of different components of the load-locking chamber are shown. Figure 6A and Figure 6B As shown, during time period A, when the first gate valve (e.g., the gate valve between the load lock chamber (LLC) and the front-end module) and the second gate valve (e.g., the gate valve between the LLC and the wafer transport chamber) are closed, the chamber pressure inside the load lock chamber can be at the initial level 602 (e.g., the chamber pressure level of the wafer transport chamber).

[0069] Return to reference Figure 5 In step 510, gas can be removed from the load-locking chamber, causing the chamber pressure inside the load-locking chamber to decrease from the initial level to a first level. For example, as... Figure 6A As shown, during time periods B and C, the chamber pressure decreases from the initial level 602 to the first level 606. Removing gas from the load-locked chamber may include opening a slow vent valve (e.g., slow vent valve 222), a fast vent valve (e.g., fast vent valve 224), or both. For example, as... Figure 6BAs shown, during time period B, the slow vent valve can be opened. Time period B can be 1 to 20 seconds long. During time period B, the slow injection valve and / or mass flow controller can also be opened to allow a purge gas (e.g., nitrogen, argon, helium, or carbon dioxide) at a flow rate of 0.1 to 10 slm. At the end of time period B, the chamber pressure inside the load-locked chamber can be at a first intermediate level 604, allowing the fast vent valve to open at the beginning of time period C. The slow vent valve can remain open during time period C. Alternatively, the fast vent valve can open at the beginning of time period C, regardless of whether the chamber pressure inside the load-locked chamber exceeds the first intermediate level. Time period C can be 1 to 10 seconds long. During time period C, the slow injection valve and / or mass flow controller can be closed. At the end of time period C, the chamber pressure inside the load-locked chamber can be at a first level 606. When removing gas from the load-locked chamber, the slow vent valve can have a flow rate of 1-500 L / min, while the fast vent valve can have a flow rate of 500-20000 L / min. At the end of time period C, both the slow exhaust valve and the fast exhaust valve can be closed.

[0070] Return to reference Figure 5 In step 512, purge gas can be supplied to the load-locking chamber, causing the chamber pressure inside the load-locking chamber to increase from a first level to a second level. For example, as... Figure 6A As shown, during time periods D and E, the chamber pressure increases from a first level 606 to a second level 610. Providing purge gas to the load-locked chamber may include opening one or more of a slow injection valve (e.g., slow injection valve 232), a mass flow controller (e.g., mass flow controller 235), and a fast injection valve (e.g., fast injection valve 234). For example, as... Figure 6B As shown, during time period D, the slow injection valve and / or mass flow controller can be opened. Time period D can be 1 to 10 seconds long. At the end of time period D, the chamber pressure inside the load lockout chamber can be at a cross level, such that at the beginning of time period E, the fast injection valve can be opened while the slow injection valve and / or mass flow controller remains open. Alternatively, the fast injection valve can be opened at the beginning of time period E, regardless of the chamber pressure inside the load lockout chamber. Time period E can be 1 to 10 seconds long. The slow injection valve can have a flow rate of 0.1-10 slm, while the fast injection valve can have a flow rate of 50-1000 slm. At the end of time period E, both the slow injection valve and / or mass flow controller and the fast injection valve can be closed.

[0071] Return to reference Figure 5Steps 510 and 512 can constitute a purging cycle. In step 514, it can be determined whether the purging cycle needs to be repeated. If another purging cycle is needed, the method can continue to step 510. If it is determined that no more purging cycles are needed, another gas removal step 514, similar to step 510, can be performed before the method ends.

[0072] Figure 7A This is a functional block diagram of the aforementioned controller (e.g., controller 28 or 250). The controller can function as a chamber state controller, controlling the state of the load-locked chamber. The controller may include a chamber pressure analyzer unit 702, which is the part that acquires information about the pressure level inside the load-locked chamber from one or more sensors (e.g., chamber pressure sensor 240) coupled to the load-locked chamber. The purge cycle execution unit 708 is responsible for executing... Figure 3 The processing and / or steps 302, 304, 306, 308, 310, 312 and 314 in the process. Figure 5 The processing steps 502, 504, 506, 508, 510, 512, 514, and 516 in the process. When processing... Figure 3 Step 312 and Figure 5 In steps 510 or 516, the gas removal unit 704 can be controlled by the purge cycle execution unit. The gas removal unit 704 can receive information about the pressure level inside the load-locked chamber from the chamber pressure analyzer unit 702 and control the opening and / or closing of the aforementioned slow exhaust valve and fast exhaust valve, as well as the opening and closing of the aforementioned dry pump. The purge gas injection unit 706 can process... Figure 3 Step 310 and Figure 5 Step 512 is controlled by the purge cycle execution unit. The purge gas injection unit 706 can receive information about the pressure level in the load lock chamber from the chamber pressure analyzer unit 702 and control the opening and closing of one or more of the aforementioned slow injection valve, mass flow controller, and fast injection valve.

[0073] The controller described above may include processing circuitry. Each of the functions performed in the controller can be implemented by at least one processing circuit. Specifically, by means of the processing circuitry, the controller performs one or more purge cycles in the load-locked chamber. The processing circuitry can be provided as dedicated hardware (dedicated circuitry) or as a CPU (central processing unit, processing device, arithmetic unit, microprocessor, microcomputer, processor, DSP) executing programs stored in memory. The processing circuitry can correspond to, for example, a single circuit, a composite circuit, a programming processor, a parallel programming processor, an ASIC, an FPGA, or a combination thereof. Each process performed by the controller can be implemented by a separate processing circuit or can be implemented jointly by processing circuits. Figure 7BAn example configuration of the controller is shown where the processing circuitry is a CPU. In this case, each function of the controller can be implemented by software or a combination of software and firmware. The software or firmware can be described as a program and can be stored in memory 710. Processor 712 can read and execute the program stored in memory 710 to implement each function. In other words, the controller may include memory 710 storing programs, which, when executed by the processing circuitry, cause each of the above steps to be performed. The memory may correspond to, for example, non-volatile or volatile semiconductor memory, such as RAM, ROM, flash memory, EPROM and EEPROM; magnetic disk; flexible disk; optical disk; mini disk; or DVD. Of course, a portion of each of the above functions can also be implemented by hardware, and another portion by software or firmware. Thus, the above functions are performed by the processor executing the program stored in memory, or by processing by dedicated circuitry.

[0074] For the purpose of summarizing the invention and its advantages relative to the prior art, certain objects and advantages of the invention have been described above. It should be understood, of course, that not all of these objects or advantages may necessarily be achieved according to any particular embodiment of the invention. Therefore, for example, those skilled in the art will recognize that the invention may be embodied or implemented in a manner that achieves or optimizes one or more advantages taught or suggested herein, without necessarily achieving other objects or advantages that may be taught or suggested herein.

[0075] All these embodiments are intended to fall within the scope of the invention disclosed herein. Those skilled in the art will readily appreciate these and other embodiments from the following detailed description of certain embodiments with reference to the accompanying drawings; however, the invention is not limited to any particular embodiment disclosed.

Claims

1. A load locking module, comprising: Load-locking chamber; At least one wafer holder configured to support a wafer in a load-locking chamber; An injection system, which is connected to the load lock chamber and configured to supply purge gas to the load lock chamber; An exhaust system, which is connected to the load lock chamber and configured to remove gas from the load lock chamber; as well as The controller is configured to remove contaminants from the load-locked chamber by: The injection system is controlled to provide purge gas inside the load-locked chamber, thereby increasing the chamber pressure inside the load-locked chamber to a first level; Control the exhaust system to remove gas from the load-locked chamber, causing the chamber pressure to decrease from a first level to a second level; and The injection system is controlled to provide purge gas inside the load-locked chamber, causing the chamber pressure to increase from the second level to the third level.

2. The load locking module according to claim 1, wherein, The exhaust system includes: First exhaust valve; and A second exhaust valve is configured to allow gas to be removed from the load-locked chamber at a faster rate than the first exhaust valve.

3. The load locking module according to claim 2, wherein, The controller is configured to control the exhaust system to remove gas from the load-locked chamber by: During a first time period, the first exhaust valve is opened to reduce the chamber pressure from the first level to an intermediate level; Close the first exhaust valve; During the second time period, the second exhaust valve is opened to reduce the chamber pressure from the intermediate level to the second level; as well as Close the second exhaust valve.

4. The load locking module according to claim 3, wherein, The second time period is longer than the first time period.

5. The load locking module according to claim 3, wherein, The controller is also configured to control the injection system to provide the purge gas inside the load-locking chamber during a portion of the first time period or the second time period.

6. The load locking module according to claim 1, wherein, The injection system includes: First injection valve; and The second injection valve allows the purge gas to be supplied to the load lock chamber at a faster rate than the first injection valve.

7. The load locking module according to claim 6, wherein, The controller is configured to control the injection system to provide the purge gas inside the load-locking chamber, such that the chamber pressure increases to the first level or the third level: Open the first injection valve; After the chamber pressure reaches the intermediate level, the second injection valve is opened to increase the chamber pressure from the intermediate level to the first or third level; as well as After the chamber pressure reaches the first or third level, close the first injection valve and the second injection valve.

8. The load locking module according to claim 1, wherein, The first level is substantially equal to the third level, and the second level is lower than both the first and third levels.

9. The load locking module according to claim 1, wherein, The controller is also configured to control the exhaust system to remove gas from the load-locked chamber after the chamber pressure increases from the second level to the third level.

10. The load-locking module of claim 1, further comprising a first gate valve coupled to the load-locking chamber and configured to allow transfer of the wafer between the load-locking chamber and the device front-end module (EFEM). in, The controller is configured to keep the first gate valve closed while removing the contaminant from the load lock chamber.

11. The load locking module of claim 1, further comprising a second gate valve coupled to the load locking chamber and configured to allow transfer of a wafer between the load locking chamber and the wafer transport chamber. in, The controller is configured to remove the contaminant from the load-locking chamber before: Set the second gate valve to the open position; and The wafer is transferred from the wafer handling chamber to the load locking chamber.

12. The load locking module according to claim 1, wherein, The purging gas includes molecular nitrogen (N2) or an inert gas.

13. A method for removing contaminants from a load-locked chamber, the method comprising: The chip is provided inside the load-locking chamber; Purge gas is supplied inside the load-locked chamber, causing the chamber pressure inside the load-locked chamber to increase to the first level; Gas is removed from the load-locked chamber, causing the chamber pressure to decrease from the first level to the second level; and Purge gas is supplied inside the load-locked chamber, causing the chamber pressure to increase from the second level to the third level.

14. The method according to claim 13, wherein, Removing gas from the load-locking chamber includes: During the first time period, the first exhaust valve is opened to reduce the chamber pressure from the first level to an intermediate level; Close the first exhaust valve; During the second time period, the second vent valve is opened to reduce the chamber pressure from the intermediate level to the second level, wherein the second vent valve removes gas from the load-locked chamber at a faster rate than the first vent valve; and Close the second exhaust valve.

15. The method according to claim 14, wherein, The second time period is longer than the first time period.

16. The method of claim 14, further comprising providing the purge gas or inert gas inside the load-locking chamber during a portion of the first time period or the second time period.

17. The method according to claim 13, wherein, Providing the purge gas inside the load-locking chamber to increase the chamber pressure to the first level or the third level includes: Open the first injection valve; After the chamber pressure reaches the intermediate level, the second injection valve is opened to increase the chamber pressure from the intermediate level to the first or third level; and After the chamber pressure reaches the first or third level, close the first injection valve and the second injection valve.

18. The method of claim 13, further comprising: After the chamber pressure increases from the second level to the third level, the gas is removed from the load-locked chamber.

19. The method of claim 13, further comprising: While removing the contaminants from the load-locked chamber, the first gate valve, which is coupled to the load-locked chamber and configured to allow the transfer of wafers between the load-locked chamber and the front-end module (FEM), is kept closed.

20. The method according to claim 13, wherein, The wafer provided inside the load-locking chamber includes: Set the second gate valve connected to the load locking chamber to the open position; The wafer is transferred from the wafer transport chamber to the load locking chamber via the second gate valve, which is in the open state; and Set the second gate valve to the closed position.

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