Reticle load lock system and method

Abstract

A reticle load lock with a variable size orifice valve or with a servo valve control is described. The servo valve control can continuously adjust the size of the orifice so that the reticle load lock can be pumped or vented at an optimal level. The servo valve control pressure curve follows an optimized pressure rate to protect the integrity of the pellicle structure. The optimized servo valve control curve minimizes the pump down and vent time without exceeding the pressure rate (dP / dt) limit. By following the optimized pressure rate curve, the servo valve control significantly reduces the time to pump down and vent and prevents the pellicle from rupturing.

Description

Cross-reference to related applications

[0001] This application claims priority to US application 63 / 602,717, filed November 27, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] The description in this article generally relates to a mask-loading lock system and method. Background Technology

[0003] Photolithography (e.g., projection) equipment can be used in, for example, the fabrication of integrated circuits (ICs). In this case, a patterning apparatus (e.g., a mask) can include or provide a pattern corresponding to a single layer (“design layout”) of the IC, and this pattern can be transferred onto a target portion (e.g., comprising one or more dies) on a substrate (e.g., a silicon wafer) that has already been coated with a layer of radiation-sensitive material (“resist”) by methods such as irradiating a target portion through the pattern on the patterning apparatus. Typically, a single substrate comprises multiple adjacent target portions, and the photolithography projection apparatus continuously transfers the pattern onto the target portions one target portion at a time. In one type of photolithography projection apparatus, the pattern on the entire patterning apparatus is transferred to a single target portion in a single operation. This type of apparatus is often referred to as a stepper. In an alternative apparatus (often referred to as a step-scan apparatus), a projection beam scans across the patterning apparatus along a given reference direction (“scanning” direction) while the substrate moves synchronously parallel to or antiparallel to that reference direction. Different portions of the pattern on the patterning apparatus are progressively transferred to a single target portion. In these lithography devices, the pattern forming apparatus is held by a pattern forming apparatus chuck with an optical contact clamp. Summary of the Invention

[0004] Some photolithography equipment operates under vacuum pressure. To introduce or remove a photomask from the equipment, the environment surrounding the photomask needs to be evacuated or vented separately. Traditional pumping or venting methods use three separate valves and orifices, which is inefficient. In this system and method, a valve with a variable-sized orifice is used for optimal pumping and venting operations. As described below, this valve is part of the photomask loading lock. By controlling the orifice size, an ideal pressure-rate curve can be followed for the fastest pumping speed without sacrificing the structural integrity of the photomask surface. Therefore, the pumping and venting time for the photomask loading lock is significantly reduced.

[0005] According to an embodiment, a mask loading lock is provided. The mask loading lock includes a loading lock chamber having a closure movable between an open position and a closed position, wherein when the closure is in the open position, a mask can be inserted into or removed from the chamber. The mask loading lock includes a pump system configured to vent the chamber. The mask loading lock includes a venting system configured to pressurize the chamber. The mask loading lock includes a first valve having a variable-sized orifice and configured to communicate the pump system with the chamber. The mask loading lock includes a second valve having a variable-sized orifice and configured to communicate the venting system with the chamber. The mask loading lock includes a controller operatively connected to the first and second valves and configured to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile.

[0006] In some embodiments, the mask loading lock further includes a pressure sensor operatively connected to the controller and configured to monitor the pressure inside the room and provide the controller with a pressure signal indicating the pressure inside the room.

[0007] In some embodiments, the controller controls the orifice size based on the pressure signal.

[0008] In some embodiments, the controller is pre-programmed to control the orifice size based on a predetermined pressure curve that varies over time.

[0009] In some embodiments, the mask includes a surface film, wherein the mask is separated from the surface film by a small air gap.

[0010] In some embodiments, the small air gap is between 50 μm and 1 mm wide.

[0011] In some embodiments, the gas is vented from the chamber to create a vacuum environment.

[0012] In some embodiments, the controller is configured to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment.

[0013] In some embodiments, the non-vacuum environment is at atmospheric pressure.

[0014] In some embodiments, the first valve and the second valve are servo control valves with orifice size control.

[0015] In some embodiments, the closure element is a gate valve.

[0016] According to an embodiment, a photolithography apparatus is provided. The photolithography apparatus includes an irradiation system that provides a radiation beam. The photolithography apparatus includes a support structure that supports a photomask, wherein the photomask is configured to impart a pattern in its cross-section to the radiation beam. The photolithography apparatus includes a substrate support that supports a substrate. The photolithography apparatus includes a projection system that projects the patterned beam onto a target portion of the substrate. The photolithography apparatus includes a photomask loading lock. The photomask loading lock includes a loading lock chamber having a closure movable between an open position and a closed position, wherein when the closure is in the open position, the photomask can be inserted into or removed from the chamber. The photomask loading lock includes a pump system configured to vent the chamber. The photomask loading lock includes a venting system configured to pressurize the chamber. The photomask loading lock includes a first valve having a variable-sized orifice and configured to communicate the pump system with the chamber. The mask-mounted lock includes a second valve having a variable-sized orifice and configured to communicate the ventilation system with the chamber. The mask-mounted lock also includes a controller operatively connected to both the first and second valves and configured to control the orifice size to regulate the pressure in the chamber over time based on a desired pressure profile.

[0017] In some embodiments, the mask-mounted lock further includes a pressure sensor operatively connected to the controller and configured to monitor the pressure inside the room and provide the controller with a pressure signal indicating the pressure inside the room.

[0018] In some embodiments, the controller controls the orifice size based on the pressure signal.

[0019] In some embodiments, the controller is pre-programmed to control the orifice size based on a predetermined pressure curve that varies over time.

[0020] In some embodiments, the mask includes a surface film, wherein the mask is separated from the surface film by a small air gap.

[0021] In some embodiments, the small air gap is between 50 μm and 1 mm wide.

[0022] In some embodiments, the gas is vented from the chamber to create a vacuum environment in the chamber.

[0023] In some embodiments, the controller is configured to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment.

[0024] In some embodiments, the non-vacuum environment is at atmospheric pressure.

[0025] In some embodiments, the first valve and the second valve are servo control valves with orifice size control.

[0026] In some embodiments, the closure element is a gate valve.

[0027] According to an embodiment, a method for loading a lock using a mask is provided. The method includes inserting a mask into or removing it from a closure when the closure of the lock chamber is in an open position, wherein the closure is movable between an open position and a closed position. The method includes evacuating the chamber using a pump system. The method includes pressurizing the chamber using a venting system. The method includes communicating the pump system to the chamber using a first valve with a variable-sized orifice. The method includes communicating the venting system to the chamber using a second valve with a variable-sized orifice. The method includes using a controller operatively connected to the first and second valves to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile.

[0028] In some embodiments, the method further includes monitoring the pressure in the room using a pressure sensor operatively connected to the controller, and using the pressure sensor to provide the controller with a pressure signal indicating the pressure in the room.

[0029] In some embodiments, the method further includes using the controller to control the orifice size based on the pressure signal.

[0030] In some embodiments, the method further includes pre-programming the controller to control the orifice size based on a predetermined pressure curve that varies over time.

[0031] In some embodiments, the mask includes a surface film, wherein the mask is separated from the surface film by a small air gap.

[0032] In some embodiments, the small air gap is between 50 μm and 1 mm wide.

[0033] In some embodiments, the gas is vented from the chamber to create a vacuum environment in the chamber.

[0034] In some embodiments, the method further includes using the controller to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment.

[0035] In some embodiments, the non-vacuum environment is at atmospheric pressure.

[0036] In some embodiments, the first valve and the second valve are servo control valves with orifice size control.

[0037] In some embodiments, the closure element is a gate valve.

[0038] According to an embodiment, a method for using a mask loading lock is provided. The method includes inserting a mask into a loading lock chamber via a closure member when the closure member is in an open position, wherein the closure member is movable between an open position and a closed position. The method includes venting the loading lock chamber by using a pump system and a first valve having a variable-sized orifice, and by controlling the size of the orifice using a controller operatively connected to the first valve to control the pressure in the chamber over time based on a desired pumping pressure curve. The method includes moving the mask from the loading lock chamber to a lithography apparatus. The method includes exposing a substrate using a pattern of the mask in the lithography apparatus. The method includes moving the mask from the lithography apparatus to the loading lock chamber. The method includes venting the loading lock chamber by using a venting system and a second valve having a variable-sized orifice, and by controlling the size of the orifice using a controller operatively connected to the second valve to control the pressure in the chamber over time based on a desired venting pressure curve. The method includes removing the mask from the loading lock chamber via the closure member when the closure member is in the open position.

[0039] In some embodiments, the method further includes monitoring the pressure in the room using a pressure sensor operatively connected to the controller, and using the pressure sensor to provide the controller with a pressure signal indicating the pressure in the room.

[0040] In some embodiments, the method further includes using the controller to control the orifice size based on the pressure signal.

[0041] In some embodiments, the method further includes pre-programming the controller to control the orifice size based on a predetermined pressure curve that varies over time.

[0042] In some embodiments, the mask includes a surface film, wherein the mask is separated from the surface film by a small air gap.

[0043] In some embodiments, the small air gap is between 50 μm and 1 mm wide.

[0044] In some embodiments, the gas is vented from the chamber to create a vacuum environment in the chamber.

[0045] In some embodiments, the method further includes using the controller to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment.

[0046] In some embodiments, the non-vacuum environment is at atmospheric pressure.

[0047] In some embodiments, the first valve and the second valve are servo control valves with orifice size control.

[0048] In some embodiments, the closure element is a gate valve. Attached Figure Description

[0049] One or more embodiments are illustrated in conjunction with the accompanying drawings, which are included and form part of this specification, and these embodiments are explained together with the specification. The embodiments will now be described by way of example only with reference to the accompanying drawings, in which corresponding reference numerals indicate corresponding parts, and wherein:

[0050] Figure 1A This is a schematic diagram of a reflective lithography apparatus according to an embodiment of the present disclosure.

[0051] Figure 1B This is a schematic diagram of a transmission lithography apparatus according to an embodiment of the present disclosure.

[0052] Figure 1C This is a more detailed schematic diagram of a reflective lithography apparatus according to an embodiment of the present disclosure.

[0053] Figure 2 An embodiment of a photolithography unit or cluster according to an embodiment is schematically depicted.

[0054] Figure 3A This is a schematic diagram of a mask-mounted lock according to an embodiment of the present disclosure.

[0055] Figure 3B This is a perspective view of a mask-mounted lock according to an embodiment of the present disclosure.

[0056] Figure 4A It is a pressure rate curve for ventilation according to an embodiment of the present disclosure.

[0057] Figure 4B This is a pressure-rate curve for pumping according to an embodiment of the present disclosure.

[0058] Figure 5 A method for loading a lock using a mask, according to an embodiment, is shown.

[0059] Figure 6 This is a block diagram of an example computer system according to an embodiment. Detailed Implementation

[0060] In photolithography, exposure must be performed under vacuum pressure. With the latest advancements in extreme ultraviolet (EUV) lithography, EUV radiation sources require vacuum conditions. Therefore, the entire EUV lithography system is maintained under vacuum pressure. Furthermore, exposure requires the use of many different masks to form the desired pattern on the substrate. The environment around the mask can be pumped out in a mask loading lock before the mask enters the EUV lithography system.

[0061] However, conventional mask loading locks are inefficient and not optimized for throughput. Conventional mask loading locks typically use three separate valves and orifices. These locks use a first valve with a small orifice size to pump or vent to a certain pressure, at which point a second valve with a medium orifice size takes over. After pumping or venting to a second pressure, a third valve with a large orifice size replaces the second valve. The third valve then pumps or vents the mask loading lock to either vacuum or atmospheric pressure. As the mask loading lock is further pumped, the orifice size increases. The problem with this typical three-part valve system is that each of the three valves and orifices pumps at a fixed, non-adjustable rate. Typically, the pumping or venting speed can only be changed as the orifice size changes. Since the sizes of the three orifices are fixed and cannot be adjusted, it is impossible to change the pumping or venting speed unless switching between the three orifices. Therefore, the typical three-part valve system limits how quickly the loading lock can be pumped or vented. Alternatively, a conventional mask plate loading lock has only one fixed-size valve. This loading lock will pump more slowly than a loading lock with three separate valves and orifices.

[0062] In contrast, the valve with a variable-size orifice or the mask loading lock with servo-valving described herein solves the problems associated with three separate valve systems. The servo-controlled valve or proportional valve can continuously adjust the orifice size, allowing the mask loading lock to be pumped at an optimal level. Compared to existing systems, the servo-valving pressure profile follows a larger pressurization rate while maintaining the structural integrity of the diaphragm attached to the mask. The diaphragm is a thin, transparent membrane covering the mask to prevent contaminants from reaching its surface. The optimized servo-valving profile minimizes pumping and venting times without exceeding the pressure rate (dP / dt) limit. By following the optimized pressure rate profile, servo-valving significantly reduces the time required to pump and / or vent the loading lock chamber compared to conventional methods. Furthermore, the servo valve system and method described herein allow for greater flexibility by adjusting the orifice to any size and can be easily programmed for different pumping and / or venting rates.

[0063] While specific references may be made herein to the manufacture of integrated circuits (ICs), it should be understood that the descriptions herein may have other possible applications. For example, they may be used to manufacture integrated optical systems, guide and detection patterns for magnetic domain memories, liquid crystal display panels, thin-film magnetic heads, etc. Those skilled in the art will understand that, in the context of such alternative applications, any use of the terms “mask,” “wafer,” or “die” herein is to be considered synonymous with the more general terms “mask,” “substrate,” and “target portion,” respectively. Furthermore, any use of the terms “mask” or “mask” herein is to be considered synonymous with the more general term “patterning apparatus.”

[0064] As an introduction, before a pattern is transferred from a patterning apparatus (such as a mask) to a substrate, the substrate may undergo various processes, such as resist coating, photoresist application, and soft baking. After exposure, the substrate may undergo other processes (“post-exposure processes”), such as post-exposure baking (PEB), development, hard baking, and measurement and / or other inspection of the transferred pattern. This series of processes forms the basis for fabricating a single layer of a device (such as an IC). The substrate may then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, chemical mechanical polishing, etc., all of which are to complete a single layer of the device. If the device requires multiple layers, the entire process or variations thereof is repeated for each layer. Ultimately, each target portion on the substrate forms a device. These devices are then separated from each other using techniques such as dicing or sawing, allowing individual devices to be mounted on a carrier, connected to pins, etc.

[0065] Fabricating devices (such as semiconductor devices) typically involves processing a substrate (such as a semiconductor wafer) using a variety of manufacturing processes to form various features and multilayer structures of the device. These layers and features are typically fabricated and processed using processes such as deposition, photolithography, etching, chemical mechanical polishing, ion implantation, and / or other processes. Multiple devices can be fabricated on multiple dies on a substrate and then separated into individual devices. This device fabrication process can be viewed as a patterning process. A patterning process includes patterning steps, such as optical and / or nanoimprint lithography using a patterning apparatus in a photolithography device, to transfer a pattern from the patterning apparatus onto the substrate, and typically (but optionally) also includes one or more associated patterning processing steps, such as resist development using a developing apparatus, baking the substrate using a baking tool, etching according to the pattern using an etching apparatus, etc. A patterning process typically involves one or more metrological processes.

[0066] Photolithography is a step in the fabrication of devices such as integrated circuits (ICs), in which patterns formed on a substrate define the functional elements of the device, such as microprocessors and memory chips. Similar photolithography techniques are also used in the fabrication of flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0067] As semiconductor manufacturing processes continue to advance, the number of functional elements (such as transistors) in each device has steadily increased over the past few decades, a trend often referred to as "Moore's Law," while the size of functional components continues to shrink. At current technological levels, the layers of a device are fabricated using photolithography projection equipment. This equipment uses a deep ultraviolet irradiation source to project the design layout onto a substrate, thereby forming individual functional elements with dimensions much smaller than 100 nm, which is less than half the wavelength of the irradiation source (e.g., a 193 nm irradiation source).

[0068] The process of printing features smaller than the classical resolution limit of a photolithography projection apparatus is often referred to as low-k1 lithography. This is derived from the resolution formula CD = k1 × λ / NA, where λ is the wavelength of the radiation used (currently mostly 248 nm or 193 nm), NA is the numerical aperture of the projection optics in the photolithography projection apparatus, CD is the "critical size" (usually referring to the smallest feature size that can be printed), and k1 is an empirical resolution factor. Generally, the smaller k1 is, the more difficult it is to reproduce patterns on the substrate that are similar in shape and size to those planned by the designer to achieve specific electrical functions and performance. To overcome these difficulties, complex fine-tuning steps are applied to the photolithography projection apparatus, design layout, or patterning apparatus. These complex fine-tuning steps include, but are not limited to, optimizing NA and optical coherence settings, customizing illumination schemes, using phase-shifting patterning apparatus, performing optical proximity correction (OPC, sometimes also called "optical and process correction") in the design layout, overlay measurements, or other methods typically positioned as "resolution enhancement techniques" (RET).

[0069] As used herein, the term "projection optics" should be broadly understood to encompass various types of optical systems, including, for example, refractive optics, reflective optics, aperture optics, and catadioptric optics. The term "projection optics" may also include components for any of these design types used to guide, shape, or control a projected radiation beam, either jointly or individually. The term "projection optics" can include any optical component in a lithographic projection apparatus, regardless of its location in the optical path of the apparatus. Projection optics can include optical components for shaping, adjusting, and / or projecting radiation from a source before it passes through a patterning apparatus, and / or for shaping, adjusting, and / or projecting radiation after it has passed through the patterning apparatus. Projection optics typically do not include a source or a patterning apparatus.

[0070] Figure 1A and Figure 1BThis is a schematic illustration of lithography apparatus 100 and lithography apparatus 100', embodiments of which can be implemented in or for the lithography apparatus. Lithography apparatus 100 and lithography apparatus 100' each include: an irradiation system (irradiator) IL configured to modulate a radiation beam B (e.g., ultraviolet (UV), deep ultraviolet (DUV), or extreme ultraviolet (EUV) radiation); a support structure (e.g., a mask stage) MT configured to support a patterning apparatus (e.g., a mask, a stencil, or a dynamic patterning apparatus) MA and connected to a first positioner PM configured to accurately position the patterning apparatus MA; and a substrate stage (e.g., a wafer stage) WT (e.g., WTa, WTb, or both) configured to hold a substrate (e.g., a wafer coated with resist) W and connected to a second positioner PW configured to accurately position the substrate W. Lithography apparatus 100 and 100' also include a projection system PS configured to project a pattern, imparted by a patterning apparatus MA to a radiation beam B, onto a target portion C (e.g., comprising one or more dies) of a substrate W. In lithography apparatus 100, the patterning apparatus MA and projection system PS are reflective. In lithography apparatus 100', the patterning apparatus MA and projection system PS are transmissive.

[0071] The irradiation system IL may include various types of optical components for guiding, shaping, or controlling the radiation beam B, such as refractive, reflective, reflective-refractive, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.

[0072] The support structure MT holds the patterning apparatus MA in a manner dependent on the orientation of the patterning apparatus MA, the design of at least one of the lithography apparatuses 100 and 100', and other conditions such as whether the patterning apparatus MA is held in a vacuum environment. The support structure MT can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning apparatus MA. Depending on the requirements, the support structure MT can be, for example, a frame or stage, which can be fixed or movable. By using sensors, the support structure MT can ensure that the patterning apparatus MA is in the desired position, for example, relative to the projection system PS.

[0073] The term "patterning apparatus" MA should be interpreted broadly as any apparatus that can be used to impart a pattern to the radiation beam B in the cross-section of the radiation beam B in order to generate a pattern in a target portion C of the substrate W. The pattern imparted to the radiation beam B may correspond to a specific functional layer in the target portion C for forming an integrated circuit.

[0074] The pattern forming apparatus MA can be a transmissive type (such as in...) Figure 1B(as in a 100' lithography device) or reflective (as in...) Figure 1A (As in the photolithography apparatus 100). Examples of pattern forming apparatus MA include photomasks, masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in photolithography and include mask types such as binary, alternating phase-shift, and attenuation phase-shift masks, as well as various hybrid mask types. Examples of programmable mirror arrays use a matrix arrangement of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors impart a pattern to the radiation beam B reflected by the matrix of small mirrors.

[0075] The term "projection system" PS can encompass any type of projection system suitable for the exposure radiation used or for other factors such as the use of an immersion liquid on a substrate W or the use of a vacuum, including refractive, reflective, reflective-refractive, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof. Because other gases may absorb excessive radiation or electrons, a vacuum environment can be used for EUV or electron beam radiation. Therefore, a vacuum environment can be established throughout the beam path by means of vacuum walls and a vacuum pump.

[0076] The lithography apparatus 100 and / or lithography apparatus 100' can be of the type having two (dual-platform) or more substrate stages WT (and / or two or more mask stages). In such a "multi-platform" machine, additional substrate stages WT can be used in parallel, or one or more other substrate stages WT can be used for exposure while preparatory steps are performed on one or more stages. In some cases, the additional stage may not be a substrate stage WT. For example, alignment measurements using an alignment sensor AS and / or level (height, tilt, etc.) measurements using a level sensor LS can be performed (in... Figure 1B middle).

[0077] refer to Figure 1A and Figure 1B The irradiator IL receives the radiation beam from the radiation source SO. For example, when the source SO is an excimer laser, the source SO and the lithography apparatus 100, 100' can be separate physical entities. In such a case, the source SO is not considered to be part of the lithography apparatus 100 or 100', and the radiation beam B is delivered by means of a beam delivery system BD including, for example, suitable directional mirrors and / or beam expanders. Figure 1B (In the middle) the beam is transferred from the source SO to the irradiator IL. In other cases, for example, when the source SO is a mercury lamp, the source SO can be a component of the lithography apparatus 100, 100'. If necessary, the source SO, the irradiator IL, and the beam transfer system BD can be referred to as the radiation system.

[0078] An illuminator IL can alter the intensity distribution of the beam. The illuminator can be arranged to limit the radial range of the radiation beam such that the intensity distribution is non-zero within an annular region in the pupil plane of the illuminator IL. Alternatively or additionally, the illuminator IL can be operated to limit the beam distribution within the pupil plane such that the intensity distribution is non-zero within multiple equally spaced sectors in the pupil plane. The intensity distribution of the radiation beam within the pupil plane of the illuminator IL can be referred to as the illumination mode.

[0079] The irradiator IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam. Figure 1B (In the middle). Typically, at least the outer radial range and / or inner radial range (often referred to as "σ-outer" and "σ-inner", respectively) of the intensity distribution in the pupil plane of the irradiator can be adjusted. Additionally, the irradiator IL may include various other components ( Figure 1B (In the middle), such as integrator IN and concentrator CN. Irradiator IL can be used to adjust the radiation beam B to have the desired uniformity and intensity distribution in its cross-section.

[0080] refer to Figure 1A A radiation beam B is incident on a patterning apparatus (e.g., a mask) MA held on a support structure (e.g., a mask stage) MT and is patterned by the patterning apparatus MA. In the lithography apparatus 100, the radiation beam B is reflected from the patterning apparatus (e.g., the mask) MA. After being reflected from the patterning apparatus (e.g., the mask) MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W. The substrate stage WT can be accurately moved (e.g., to position the different target portion C in the path of the radiation beam B) by means of a second positioner PW and a position sensor IF2 (e.g., an interferometric device, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor IF1 (e.g., an interferometric device, a linear encoder, or a capacitive sensor) can be used to accurately position the patterning apparatus (e.g., the mask) MA relative to the path of the radiation beam B. The pattern forming apparatus (e.g., mask) MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0081] refer to Figure 1B Radiation beam B is incident on a patterning apparatus (e.g., mask MA) held on a support structure (e.g., mask stage MT) and patterned by the patterning apparatus. After passing through the mask MA, radiation beam B passes through a projection system PS, which focuses the beam onto the target portion C of the substrate W. The projection system PS is supported on a reference frame RF.

[0082] The terms “radiation” and “beam” used in this document cover all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., wavelengths of 365, 248, 193, 157, or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., wavelengths in the range of 5–20 nm), as well as particle beams (such as ion beams or electron beams).

[0083] Using a second positioner PW and a position sensor IF2 (e.g., an interferometric apparatus, a linear encoder, or a capacitive sensor), the substrate stage WT can be precisely moved (e.g., to position different target portions C within the path of the radiation beam B). The position sensor IF2 measures the substrate stage WT in three dimensions. In this example, the position sensor IF2 is an interferometric apparatus. A z-axis interferometer is located on the side of the substrate stage WT. An interferometric mirror has 45-degree inclined surfaces attached to the left and right sides of the substrate stage WT. An interferometric laser is mounted such that the laser beam is incident on the interferometric mirror. Figure 1B The relationship between the interferometric laser and the mirror of position sensor IF2 is shown. Similarly, the first positioner PM and another position sensor IF1 (as shown) Figure 1A (As shown) can be used to accurately position the mask MA relative to the path of the radiation beam B (e.g., after mechanical retrieval from a mask library or during scanning). The position sensor IF1 measures the mask stage MT in three dimensions. In this example, the position sensor IF1 is an interferometric measuring device. The z-direction interferometer is located on the side of the mask stage MT. The interferometric mirror has 45-degree inclined surfaces attached to the left and right sides of the mask stage MT. An interferometric laser is mounted such that the laser beam is incident on the interferometric mirror.

[0084] Typically, the mask stage MT can be moved using a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) forming the portion of the first positioner PM. Similarly, the substrate stage WT can be moved using a long-stroke module and a short-stroke module forming the portion of the second positioner PW. In the case of a stepper (relative to a scanner), the mask stage MT can be connected to a short-stroke actuator or can be fixed. The mask MA and substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks (as illustrated) occupy dedicated target portions, these marks can be located in the space between the target portions (called scribing alignment marks). Similarly, in cases where more than one die is disposed on the mask MA, the mask alignment marks can be located between the dies.

[0085] The lithography equipment 100 and 100' can be used in at least one of the following modes:

[0086] 1. In step mode, when the entire pattern applied to the radiation beam B is projected onto the target portion C in one go, the support structure (e.g., mask stage) MT and the substrate stage WT are kept substantially stationary (i.e., single static exposure). The substrate stage WT is then shifted in the X and / or Y directions so that different target portions C can be exposed.

[0087] 2. In scanning mode, while projecting the pattern applied to the radiation beam B onto the target portion C, the support structure (e.g., mask stage) MT and the substrate stage WT are scanned simultaneously (i.e., single dynamic exposure). The velocity and orientation of the substrate stage WT relative to the support structure (e.g., mask stage) MT can be determined by the magnification (reduction) and image inversion characteristics of the projection system PS.

[0088] 3. In another mode, while the pattern applied to the radiation beam B is projected onto the target portion C, the support structure (e.g., a mask stage) MT is kept substantially stationary, thereby holding the programmable patterning apparatus in place, and the substrate stage WT is moved or scanned. A pulsed radiation source SO can be used, and the programmable patterning apparatus can be updated as needed after each movement of the substrate stage WT or between successive radiation pulses during scanning. This mode of operation can be readily applied to maskless lithography utilizing programmable patterning apparatuses such as programmable mirror arrays.

[0089] Alternatively, combinations and / or variations or entirely different usage patterns described may be used.

[0090] In some embodiments, the lithography apparatus 100 includes an extreme ultraviolet (EUV) source configured to generate an EUV radiation beam for EUV lithography. Typically, the EUV source is configured in a radiation system, and a corresponding irradiation system is configured to modulate the EUV radiation beam from the EUV source.

[0091] Figure 1C A lithography apparatus 100 is shown in more detail, comprising a source-collector device SO, an irradiation system IL, and a projection system PS. The source-collector device SO is constructed and arranged such that a vacuum environment can be maintained within a closed structure 120 of the source-collector device SO. EUV radiation emission plasma 110 can be formed by a discharge-generated plasma source. EUV radiation can be generated by a gas or vapor (e.g., Xe gas, Li vapor, or Sn vapor), wherein thermal plasma 110 is generated to emit radiation in the EUV range of the electromagnetic spectrum. Thermal plasma 110 is generated, for example, by a discharge, thereby causing at least partially ionized plasma. For example, Xe, Li, Sn vapor, or any other suitable gas or vapor with a partial pressure of 10 Pa may be required to effectively generate radiation. In an embodiment, a plasma of excited tin (Sn) is provided to generate EUV radiation.

[0092] Radiation emitted by the thermal plasma 110 enters the collector chamber 112 from the source chamber 11 via an optional gas barrier or contaminant trap 113 (also referred to in some cases as a contaminant barrier or vane trap), which is positioned in or behind an opening in the source chamber 111. The contaminant trap 113 may include a channel structure. The contaminant trap 113 may also include a gas barrier or a combination of a gas barrier and a channel structure. In this document, the contaminant trap or contaminant barrier 113 is also indicated to include at least a channel structure.

[0093] Collector chamber 112 may include a radiation collector CO, which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side 151 and a downstream radiation collector side 152. Radiation passing through the collector CO may be reflected by a grating spectral filter 140 to be focused at a virtual source point IFP. The virtual source point IFP is often referred to as the intermediate focus, and the source collector device is arranged such that the intermediate focus IFP is located at or near an opening 119 in the enclosed structure 120. The virtual source point IFP is an image of the radiative emission plasma 110. The grating spectral filter 140 is particularly used to suppress infrared (IR) radiation.

[0094] Subsequently, radiation passes through an illumination system IL, which may include a faceted field mirror assembly 222 and a faceted pupil mirror assembly 224. The faceted field mirror assembly 222 and the faceted pupil mirror assembly 224 are arranged to provide a desired angular distribution of the radiation beam 21 at the patterning apparatus MA and a desired uniformity of radiation intensity at the patterning apparatus MA. When the radiation beam 221 is reflected at the patterning apparatus MA, held by the support structure MT, a patterned beam 226 is formed, and the patterned beam 226 is imaged onto a substrate W held by a wafer stage or substrate stage WT via a projection system PS through reflective elements 128 and 130.

[0095] Typically, more elements than are shown can be present in the illumination optical unit IL and the projection system PS. The grating spectral filter 140 may be optionally present depending on the type of photolithography equipment. Furthermore, more mirrors than are shown in the figures, for example, compared to... Figure 1C The reflective element shown can have 1-6 additional reflective elements in the projection system PS.

[0096] like Figure 1CThe collector optics CO illustrated in the figure are depicted as a nested collector with grazing incidence reflectors 153, 154, and 155, which is merely an example of a collector (or collector mirror). The grazing incidence reflectors 153, 154, and 155 are configured to be axially symmetrical about the optical axis O, and this type of collector optics CO is preferably used in conjunction with a discharge-generated plasma source, commonly referred to as a DPP source.

[0097] like Figure 2 As shown, the photolithography equipment 100 or 100' (in Figure 2 The lithography unit (LC), often referred to as "LA"), can form part of a lithography cluster (LC), which includes equipment for performing pre-exposure and post-exposure processes on the substrate. Typically, this equipment includes one or more spin coaters (SC) for depositing one or more resist layers, one or more developers for developing the post-exposure resist, one or more chillers (CH), and / or one or more bake plates (BK). A substrate transport device or robot (RO) picks up one or more substrates from input / output ports (I / O1, I / O2), moves the substrates between different process units, and delivers them to the lithography equipment's feed stage (LB). These devices, often collectively referred to as tracks, are controlled by a track control unit (TCU), which in turn is controlled by a management control system (SCS), which in turn controls the lithography equipment via the lithography control unit (LACU). Therefore, different devices can be operated to maximize throughput and processing efficiency.

[0098] To correctly and consistently expose a substrate exposed by a photolithography apparatus, and / or to monitor a portion of a patterning process (e.g., a device fabrication process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is desirable to examine the substrate or other object to measure or determine one or more properties, such as alignment, overlap (which may be, for example, between structures in a stacked layer, or between structures in the same layer that have been separately provided to said layers by, for example, a double patterning process), line thickness, critical dimension (CD), focus offset, or material properties, etc. For example, contaminants on a mask holder diaphragm (e.g., as described herein) can adversely affect overlap because clamping the mask on such contaminants will deform the mask. Therefore, the fabrication facility in which the photolithography unit LC is located typically also includes a metrology system that measures the substrate W (which has been processed in the photolithography unit) Figure 1A-1C The measurement system may be part of the lithography unit LC, for example, it may be part of the lithography apparatus 100 or 100'.

[0099] For example, one or more measurement parameters may include alignment, overlap between successive layers formed in or on a patterned substrate, critical dimensions (CD) (e.g., critical linewidth) of features formed in or on a patterned substrate, focusing or focusing errors of the optical lithography step, dose or dose errors of the optical lithography step, optical aberrations of the optical lithography step, and so on. Such measurements can be performed on a target on the product substrate itself and / or on a dedicated measurement target set on the substrate. The measurement can be performed after resist development, but before etching, after etching, after deposition, and / or at other times.

[0100] Various techniques exist for measuring structures formed during patterning processes, including the use of scanning electron microscopy, image-based measurement tools, and / or various specialized instruments. As mentioned above, a rapid and non-invasive specialized measurement tool is one that directs a radiation beam onto a target on a substrate surface and measures the properties of the scattered (diffracted / reflected) beam. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. This can be called diffraction-based measurement. One such application of diffraction-based measurement is the measurement of characteristic asymmetries within a target. For example, this can be used as a measure of overlap, but other applications are also known. For example, asymmetry can be measured by comparing relative portions of the diffraction spectrum (e.g., comparing the -1st and +1st orders in the diffraction spectrum of a periodic grating). Another application of diffraction-based measurement is the measurement of the characteristic width (CD) within a target.

[0101] Therefore, during device fabrication processes (e.g., patterning processes, photolithography processes, etc.), substrates or other objects may undergo various types of measurements during or after the process. These measurements can determine the presence of defects in a particular substrate, establish adjustments to the processes and equipment used in them (e.g., aligning two layers on a substrate or aligning a patterning apparatus with a substrate), measure the performance of processes and equipment, or be used for other purposes. Examples of measurements include optical imaging (e.g., optical microscopy), non-imaging optical measurements (e.g., diffraction-based measurements, such as the ASML YieldStar metrology tool, ASML SMASH metrology system), mechanical measurements (e.g., profilometry using styluses, atomic force microscopy (AFM)), and / or non-optical imaging (e.g., scanning electron microscopy (SEM)).

[0102] Measurement results can be provided directly or indirectly to the management and control system (SCS). If an error is detected, adjustments can be made to the exposure of subsequent substrates (especially if the inspection can be completed quickly and sufficiently so that one or more other substrates in the batch are still exposed) and / or to the subsequent exposure of already exposed substrates. Furthermore, already exposed substrates can be stripped and reworked to increase yield, or discarded to avoid further processing of substrates known to be defective. In cases where only some target portions of the substrate are defective, further exposure can be performed only on those target portions that meet specifications.

[0103] In a metrology system, metrology equipment is used to determine one or more properties of a substrate, particularly how one or more properties vary between different substrates, or how different layers of the same substrate vary between layers. As mentioned above, metrology equipment can be integrated into a lithography machine (LA) or a lithography unit (LC), or it can be a stand-alone device.

[0104] To achieve measurement, one or more targets can be formed on the substrate. In embodiments, the targets are specially designed and may include periodic structures. In embodiments, the targets are part of a device pattern, such as a periodic structure of the device pattern. In embodiments, the device pattern is a periodic structure of a memory device (e.g., a bipolar transistor (BPT), bit line junction (BLC), or similar structure).

[0105] In one embodiment, the target on the substrate may include one or more 1-D periodic structures (e.g., gratings) printed such that, after development, the periodic structure features are composed of solid resist lines. In another embodiment, the target may include one or more 2-D periodic structures (e.g., gratings) printed such that, after development, the one or more periodic structures are composed of solid resist pillars or vias in the resist. Alternatively, the strips, pillars, or vias may be etched into the substrate (e.g., etched into one or more layers on the substrate).

[0106] In this embodiment, one of the parameters of interest in the patterning process is overlap. Overlap can be measured using dark-field scattering measurements, where zero-order refraction (corresponding to specular reflection) is blocked, and only higher orders are processed. Refraction-based overlap measurement using dark-field detection of refraction order enables overlap measurement of smaller targets. These targets may be smaller than the illumination spot and may be surrounded by a device product structure on a substrate. In this embodiment, multiple targets can be measured in a single radiation capture.

[0107] As lithography nodes continue to shrink, increasingly complex wafer designs are becoming possible. Designers can use a variety of tools and / or techniques to ensure that complex designs are accurately transferred onto physical wafers. These tools and techniques can include mask optimization, source mask optimization (SMO), OPC, control design, and / or other tools and / or techniques. For example, a source mask optimization process is described in U.S. Patent No. 9,588,438 entitled "Optimization Flows of Source, Mask and Projection Optics," which is incorporated herein by reference in its entirety.

[0108] This system and / or method can be used as a standalone tool and / or technique, and / or can be used in conjunction with semiconductor manufacturing processes to enhance the accurate transfer of complex designs to physical wafers.

[0109] Figure 3A A mask loading lock 300 is shown. The mask loading lock 300 includes a loading lock chamber 301, closures 302A and 302B, a pump system 303A, a venting system 303B, controllers 304A and 304B, valves 305A and 305B, a pressure sensor 306, closure actuators 307A and 307B, robots 308A and 308B, a vacuum chamber 310A, and an atmospheric chamber 310B. The loading lock chamber 301 includes a closed housing or space that can be pumped down to a vacuum condition or vented back to atmospheric conditions. The loading lock chamber 301 has closures 302A and 302B configured to facilitate the insertion or removal of a mask or mask MA. Closures 302A and 302B are movable between an open position and a closed position. Figure 3A Closures 302A and 302B are shown in the closed position. Closures 302A and 302B can be moved to the open position using closure actuators 307A and 307B, respectively. In some embodiments, closures 302A and 302B are gate valves. In another embodiment, closures 302A and 302B are doors that move between an open position and a closed position. In another embodiment, different types of valves can be used for closures 302A and 302B. Vacuum closure 302A is an opening that can be opened to connect loading lock chamber 301 to vacuum chamber 310A, and atmospheric closure 302B is an opening that can be opened to connect loading lock chamber 301 to atmospheric chamber 310B. Insertion or removal of mask MA can be performed by robots 308A and 308B, such as by a robotic arm (in... Figure 3A The arrow is shown in the middle; Figure 3B (More details are shown in the image) Execution.

[0110] On the vacuum side of loading lock chamber 301, robot 308A is an in-vacuum robot (IVR) that transports mask MA from loading lock chamber 301 to vacuum chamber 310A and vice versa. The transport of mask MA by robot 308A is accomplished via vacuum closure 302A. Closure 302A opens only when mask MA is ready to move between chambers. Vacuum closure 302A is opened and closed by vacuum closure actuator 307A. Pump system 303A is a vacuum pump configured to evacuate loading lock chamber 301 from atmospheric pressure to vacuum pressure. Pump system 303A empties loading lock chamber 301 by pumping air out of chamber 301 until a vacuum level is reached. The pumping speed of loading lock chamber 301 is controlled by vacuum valve 305A and vacuum controller 304A. Vacuum valve 305A has a variable-size orifice that can be controlled by vacuum controller 304A. Vacuum valve 305A is configured to connect pump system 303A to chamber 301, allowing pump system 303A to pump gas out of chamber 301. Vacuum valve 305A can be a servo-controlled valve, a proportional valve, or any other suitable type of valve. For example, valve 305A can be a servo-controlled variable flow valve for pumping. The orifice size of vacuum valve 305A affects the rate at which chamber 301 can be evacuated. A larger orifice size allows for a higher evacuation rate of pump system 303A, and a faster vacuum condition is reached in chamber 301. Controller 304A can enlarge the orifice size of valve 305A to increase the pumping speed. Alternatively, controller 304A can also reduce the orifice size of valve 305A to decrease the pumping speed. Vacuum controller 304A is operatively connected to vacuum valve 305A and is configured to control the orifice size to control the pressure in chamber 301 over time based on a desired pressure profile.

[0111] On the atmospheric side of loading lock chamber 301, robot 308B, an external vacuum robot (OVR), transports mask MA from loading lock chamber 301 to atmospheric chamber 310B and vice versa. The transport of mask MA by robot 308B is accomplished via atmospheric closure 302B. Closure 302B opens only when mask MA is ready to move between chambers. Atmospheric closure 302B is opened and closed by atmospheric closure actuator 307B. Ventilation system 303B introduces air into loading lock chamber 301 to bring chamber 301 from vacuum pressure to atmospheric pressure. Ventilation system 303B delivers pressurized clean dry air (CDA) to chamber 301, but other suitable gases may also be used. The rate of ventilation of loading lock chamber 301 is controlled by atmospheric valve 305B and atmospheric controller 304B. Atmospheric valve 305B has a variable-sized orifice that can be controlled by atmospheric controller 304B. Atmospheric valve 305B is configured to connect ventilation system 303B to chamber 301, allowing ventilation system 303B to introduce gas into chamber 301. Atmospheric valve 305B can be a servo-controlled valve, a proportional valve, or any other suitable type of valve. For example, valve 305B can be a servo-controlled variable flow valve for ventilation. The orifice size of atmospheric valve 305B affects the rate at which chamber 301 can be ventilated. A larger orifice size allows for a higher ventilation rate from ventilation system 303B, and a faster rate at which chamber 301 reaches atmospheric conditions. Controller 304B can enlarge the orifice size of valve 305B to increase the ventilation rate. Alternatively, controller 304B can also decrease the orifice size of valve 305B to reduce the ventilation rate. Atmospheric controller 304B is operatively connected to atmospheric valve 305B and is configured to control the orifice size to regulate the pressure in chamber 301 over time based on a desired pressure profile.

[0112] Now will describe Figure 3A The mask arrangement is shown. A surface layer PEL can be attached to the mask MA to prevent particles from reaching the mask MA. The surface layer PEL is a thin, transparent diaphragm covering the mask MA to prevent contaminants from reaching the mask surface. The surface layer PEL acts as a protective shield or filter to prevent dust or contaminant particles from interfering with the imaging of the pattern on the mask MA, thereby causing defects in the imaged wafer. The surface of the surface layer PEL is not flush with the pattern on the mask MA, so that dust particles attached to the surface layer PEL will remain out of focus during exposure. When attached, a small air gap AG is maintained between the surface layer PEL and the mask MA. The air gap AG is approximately 200 μm wide, but can range from 100 μm to 300 μm or from 50 μm to 1 mm.

[0113] Figure 3BA perspective view of the mask loading lock 300 is shown. On the vacuum side, the loading lock chamber 301 is used for pumping or venting the mask MA. After pumping, the mask MA is conveyed by an in-vacuum robot (IVR) 308A through a closure 302A located on the right side of the loading lock chamber 301. Figure 3B Not shown in the image; see also Figure 3A The mask MA is temporarily stored in the vacuum library (IVL) 331 before use. Afterwards, the IVR 308A retrieves the desired mask MA from the IVL 331 and provides it to the mask exchange device (RED) 332. RED 332 is used to change the mask during the photolithography process with the least possible amount of time. On the atmospheric side, the loading port 320 serves as the photolithography apparatus 100 or 100' (Figure 1 A-). Figure 1C The photomask MA is introduced into the lithography apparatus 100 or 100' via the loading port. An external vacuum robot (OVR) 308 B retrieves the photomask MA from the loading port 320 and passes it through the closure 302 B located on the left side of the loading lock chamber 301. Figure 3B Not shown in the image; see also Figure 3A The mask plate MA is brought to the loading lock chamber 301 for pumping.

[0114] Figure 3B The right side shows the replacement of the mask MA, which is attached to the surface film PEL and rests on the support structure MT, by RED 332. The air gap AG between the mask MA and the surface film PEL is not drawn, but it is still present. RED 332 removes one mask MA and surface film PEL from the support structure MT and replaces them on the support structure MT with another mask MA and surface film PEL.

[0115] When the mask MA is placed in chamber 301, the gas in chamber 301 can be vented to bring the mask MA into a vacuum environment. The gas can be allowed to return to chamber 301 to bring chamber 301 from a vacuum environment to a non-vacuum environment (at atmospheric pressure). Pump system 303A and venting system 303B are configured to vent or pressurize chamber 301, respectively. Pressure sensor 306 is operatively connected to controllers 304A and 304B and is configured to monitor the pressure within chamber 301 and provide a pressure signal indicating the pressure within chamber 301 to controllers 304A and 304B. Therefore, controllers 304A and 304B control the orifice size based on the pressure signal. Furthermore, controllers 304A and 304B are pre-programmed to control the orifice size based on a predetermined pressure curve changing over time. Pressure sensor 306 can be a pressure transducer or any other type of detector capable of measuring the pressure within chamber 301.

[0116] Figure 3A and Figure 3B The mask plate loading lock 300 shown can be Figures 1A-1C This is a part of the lithography apparatus 100 or 100' shown. Alternatively, the mask loading lock 300 may be separate from the lithography apparatus 100 or 100', but connected to the lithography apparatus 100 or 100'.

[0117] Evacuation is the process of bringing chamber 301, initially at atmospheric pressure, to a vacuum pressure. This is accomplished by evacuating gas from chamber 301 using pump system 303A. The continuous removal of gas from chamber 301 eventually brings it to a vacuum condition. Evacuation is performed to bring the mask MA from the surrounding environment of the lithography equipment 100 or 100' to a vacuum condition. On the other hand, venting is accomplished using venting system 303B and is the process of bringing chamber 301 from vacuum pressure to atmospheric pressure. Venting introduces gas back into chamber 301 to increase the pressure. The continuous introduction of gas into chamber 301 eventually brings it to atmospheric conditions. Venting is typically performed after evacuation.

[0118] Because of the small air gap AG between the mask MA and the membrane PEL, the pressure change over time generated by the pump system 303 A or the ventilation system 303 B in chamber 301 must not exceed a specific value to prevent the membrane PEL from rupturing. If the pressure change is too rapid, the air gap AG will expand or contract too much, causing the thin diaphragm of the membrane PEL to rupture. Therefore, the rate of pressure change must be monitored by the pressure sensor 306 to ensure that the rate of pressure change remains below a predetermined threshold. By reducing the pressure change, the air gap AG expands or contracts more slowly, which minimizes the stress acting on the membrane PEL. A pressure profile over time for ventilation or evacuation has been determined to minimize ventilation and / or evacuation time while maintaining the structural integrity of the membrane PEL. An optimal pressure profile over time has been determined based on modeling and / or testing. By closely following this pressure profile over time, it can be ensured that chamber 301 is evacuated or vented at the highest possible rate without damaging the membrane PEL.

[0119] Furthermore, there is a finely controlled orifice size to maintain the pressure in the loading lock close to the established pressure profile during venting and pumping. This requires close pressure monitoring using a pressure sensor 306 (such as a pressure transducer), which sends a pressure signal to controllers 304A and 304B, which in turn closely control the valve opening size (making it larger or smaller) to ensure the pressure remains within the positive or negative range of the pressure profile. This is an iterative / continuous process.

[0120] Pressure sensor 306 provides real-time feedback on the pressure within chamber 301 to controllers 304A and 304B. This enables an iterative and continuous process to ensure the pressure remains within ±5% of the pressure curve. Therefore, the orifice sizes of valves 305A and 305B can be enlarged, reduced, or kept the same to optimize the pressure rate. Based on the pressure signal measured by pressure sensor 306, controllers 304A and 304B can determine how the orifice sizes should be adjusted (if possible). Modifying the orifice sizes of valves 305A and 305B maximizes pumping / venting speed and protects diaphragm integrity.

[0121] On the other hand, if the mask MA does not use a surface PEL, it can be evacuated and ventilated more quickly in the mask loading lock 300 compared to the case where a surface PEL is used. Since there is no surface PEL or air gap AG to worry about, the mask MA can be evacuated or ventilated more quickly.

[0122] Figure 4A The pressure-rate curves for ventilation are shown, and Figure 4B The pressure curve used for evacuation is shown. The pressure rate curve shows the pressure rate (dP / dt) as a function of pressure. The pressure rate (dP / dt) is the change in pressure over time. The greater the change in pressure over a short time period, the higher the pressure rate. A higher pressure rate will allow for faster evacuation or degassing. However, if the pressure rate is too high, the membrane PEL will be affected by the air gap AG ( Figure 3A Therefore, the limiting factor for the pressure rate is ensuring the structural integrity of the PEL membrane. Pressure sensor 306 measures the pressure within the loading lock chamber 301. In this example, this value is measured in Pascals (Pa). Furthermore, the pressure rate (dP / dt) can be calculated by acquiring the change in pressure measured by pressure sensor 306 over a certain time period. For example, if pressure sensor 306 measures pressure per second, the difference between two measurements will be the pressure rate.

[0123] As described above, the mask-mounted loading lock 300 is configured to facilitate the use of a servo-controlled valve. Servo valve control is achieved by using orifices with variable dimensions to quickly pump the loading lock chamber 301 to a vacuum level or vent the chamber 301 back to atmospheric pressure. Discontinuous valve control is a conventional method of pumping and / or venting using three separate valves and orifices. Venting has a different pressure profile than pumping. Figure 4A The ventilation curve shown represents pressures from 0.1 Pa (vacuum pressure) to 10 Pa. 5 Pa (atmospheric pressure). It should be from left (0.1 Pa) to right (10 Pa). 5 Pa) read Figure 4A The ventilation curve. Conversely, Figure 4B The pumping curve shown represents the pressure from 10... 5 The pump was pumped down to 0.1 Pa (vacuum pressure). Figure 4B The pumping curve should be from the right (10) 5 Read from 0.1 Pa to the left. Although the pressure profiles are different, each process in servo valve control takes approximately 90 seconds. Compared to typical discontinuous valve control, the combination time is significantly reduced. For example, discontinuous valve control typically takes approximately 220 seconds for venting and 160 seconds for pumping. Discontinuous valve control uses three separate valves and orifices, which can be viewed as three distinct steps in the diagram. Figure 4A In the diagram, three separate steps are shown as A1, A2, and A3. A1 vents with one orifice size, followed by A2 with different orifice sizes, and finally A3 with a third orifice size to bring the pressure to atmospheric pressure. The orifice size increases as venting progresses from A1 to A3. In other words, the orifice size is smallest for A1, medium for A2, and largest for A3. Figure 4B Three discrete steps are shown as B1, B2, and B3. Similarly, B1 pumps with the first orifice size, then B2 pumps with the second orifice size, and finally B3 pumps chamber 301 to vacuum pressure with the third orifice size. The orifice size increases as pumping progresses from B1 to B3. In other words, the orifice size is smallest for B1, medium for B2, and largest for B3. Discontinuous valve control is not optimal because the loading lock can pump faster if the diaphragm is damaged. However, since there are only three valves, each with a fixed orifice size, pumping and / or venting cannot be utilized at the optimal rate. Therefore, servo valve control is faster because the orifice adjusts incrementally. The servo valve control pressure curve follows a larger pressure rate but still maintains the structural integrity of the diaphragm. The optimized servo valve control curve minimizes pumping and venting times without exceeding the pressure rate (dP / dt) limit. The region between the servo valve curve and the discrete valve curve represents wasted yield. Therefore, the servo valve significantly reduces the pumping time within the mask loading lock. Using the servo valve control method doubles the throughput through the loading lock.

[0124] Furthermore, by using servo valves or proportional valves, updates can be easily made to achieve multiple pressure-rate profiles, or the profiles can be changed via software. No additional valves and orifices are required. Instead, servo valves with variable-size orifices can be programmed to the desired dimensions. Therefore, any desired pumping or venting speed can be achieved.

[0125] Figure 5A method 500 for loading a lock using a mask is illustrated. In some embodiments, one or more operations of method 500 may be controlled by one or more processors and / or computing systems, as described below (see [link]). Figure 6 The operation of method 500 presented below is intended to be illustrative. In some embodiments, method 500 may be performed with or without one or more of the operations discussed, and / or in the presence of one or more additional operations not described. Figure 5 The order of operations of method 500 shown and described below is not intended to be limiting.

[0126] In some embodiments, one or more operations of method 500 may be performed in one or more processing devices (e.g., digital processor, analog processor, digital circuitry designed to process information, analog circuitry designed to process information, state machine, and / or other mechanisms for electronically processing information, as described below). Figure 6 The method 500 is implemented and / or controlled by the one or more processing devices described herein. The one or more processing devices may include one or more means that perform some or all of the operations of method 500 in response to instructions electronically stored on an electronic storage medium. The one or more processing devices may include one or more means configured by hardware, firmware, and / or software specifically designed to perform one or more operations in method 500 (e.g., see below regarding...). Figure 6 (Discussion).

[0127] At operation 501, the mask MA is inserted from the atmospheric chamber 310B into the loading lock chamber 301 through the closure 302B, as follows. Figure 3A As shown. Insertion can be performed by robot 308B. When the mask MA is inserted, the loading lock chamber 301 is at atmospheric pressure or ambient pressure. In other words, the pressure inside the loading lock chamber 301 is the same as the pressure in the room.

[0128] At operation 502, gas is discharged from loading lock chamber 301 using pump system 303A via vacuum valve 305A with a variable-sized orifice, such as... Figure 3A As shown. By controlling the orifice size, the pressure in chamber 301 can be controlled over time. The orifice size is proportional to the pumping rate at which chamber 301 is loaded. The larger the orifice size, the faster the gas is removed from chamber 301. The orifice size can be determined based on a known pressure profile that maintains the structural integrity of the membrane PEL attached to the mask MA. A vacuum controller 304A, operatively connected to valve 305A, pumps chamber 301 based on the desired pumping pressure profile. The desired pumping pressure rate profile is shown in... Figure 4BThe curve is shown as a servo valve control curve. By closely following the pressure-rate curve, the pumping time can be optimized without damaging the diaphragm PEL. Pumping ends when the desired pressure (which is the vacuum pressure in this example) has been reached.

[0129] At operation 503, the mask MA is moved from... Figure 3A The loading lock chamber 301 in the middle moves to Figure 1A-1C The photolithography equipment 100 or 100' is used. This is performed by a robot 308A, etc. The mask MA, under vacuum pressure, will enter the photolithography equipment 100 or 100', which is also under vacuum pressure. The mask MA will be placed on the mask stage MT, as... Figure 1A-1C As shown.

[0130] In operation 504, Figure 1A-1C In the photolithography apparatus 100 or 100', the substrate W is exposed to a pattern on the mask MA. A radiation beam B emitted from the source SO is incident on the mask MA and the mask pattern is used to expose the substrate W. Thus, the pattern of the mask MA is patterned onto the substrate W. Before exposure is complete, all target portions C of the substrate W are exposed to the mask MA.

[0131] At operation 505, move the mask MA from... Figure 1A-1C The lithography equipment 100 or 100' in the middle is moved to Figure 3A Loading lock chamber 301 is performed by robot 308 A, etc. This can be done by the same robot arm or a different robot arm in operation 503. At this time, loading lock chamber 301 is still under vacuum pressure.

[0132] After operation 505 is completed, operation 506 is performed. Operation 506 involves ventilating the loading lock chamber 301 using the ventilation system 303B and a ventilation valve 305B with a variable-sized orifice, such as... Figure 3A As shown. By controlling the orifice size, the pressure in chamber 301 can be controlled over time. The orifice size is proportional to the rate at which the loading lock chamber 301 is vented. The larger the orifice size, the faster the gas enters chamber 301. The orifice size can be determined based on a known pressure profile that maintains the structural integrity of the membrane PEL attached to the mask MA. The venting controller 304B, operatively connected to valve 305B, vents chamber 301 based on the desired venting pressure profile. The desired venting pressure rate profile is shown in... Figure 4A The curve is shown as a servo-controlled valve. By closely following the pressure-rate curve, the ventilation time can be optimized without disrupting the membrane PEL. Ventilation ends when the desired pressure (atmospheric pressure in this example) has been reached.

[0133] At operation 507, the mask MA is removed from the loading lock chamber 301 to the atmospheric chamber 310B via the atmospheric closure 302B, as... Figure 3A As shown. This removal can be performed by robot 308B. When the mask is removed, the loading lock chamber 301 is at atmospheric pressure or ambient pressure. In other words, the pressure inside the loading lock chamber 301 is the same as the pressure in the room.

[0134] The mask mounting lock 300 is not limited to masks. Other components that need to be brought to vacuum pressure can also use the mounting lock, such as components of the substrate W, source SO, irradiator IL, or projection system PS.

[0135] Figure 6 This is a block diagram illustrating a computer system CS that can help implement the methods, processes, or systems(s) disclosed herein. The computer system CS may be included in and / or electrically coupled to the aforementioned lithography apparatus 100 or 100' (Figures 1 A-1C). The computer system CS includes a bus BS or other communication mechanism for communicating information, and a processor PRO1 (or multiple processors PRO1, PRO2, etc.) coupled to the bus BS for processing information. The computer system CS also includes main memory MM (such as random access memory (RAM)) or other dynamic storage device coupled to the bus BS for storing instructions and information to be executed by the processor PRO1. The main memory MM may also be used to store temporary variables or other intermediate information during instruction execution by the processor PRO1. The computer system CS also includes read-only memory ROM or other static storage device coupled to the bus BS for storing static information and instructions for the processor PRO. A storage device SD, such as a disk or optical disk, is provided and coupled to the bus BS for storing information and instructions.

[0136] The computer system CS can be coupled via a bus BS to a display DS for displaying information to the computer user, such as a cathode ray tube (CRT), flat panel display, or touchpad display. An input device ID, including alphanumeric keys and other keys, is coupled to the bus BS for communicating information and command selections to the processor PRO1. Another type of user input device is a cursor controller CC, such as a mouse, trackball, or cursor direction keys, for communicating directional information and command selections to the processor ROM and for controlling cursor movement on the display DS. This type of input device typically has two degrees of freedom on two axes (i.e., a first axis (e.g., x) and a second axis (e.g., y)), allowing the device to specify its position in a plane. A touchpad (screen) display can also be used as an input device.

[0137] According to one embodiment, a computer system CS can execute all of one or more processes and / or methods as described herein in response to processor PRO1 executing one or more sequences of one or more instructions included in main memory MM. These instructions can be read into main memory MM from another computer-readable medium, such as storage device SD. Execution of the instruction sequence included in main memory MM causes processor PRO1 to execute the processes and / or process steps described herein. One or more processors arranged in a multiprocessor configuration may also be employed to execute the instruction sequence included in main memory MM. In alternative embodiments, hard-wired circuitry may be used instead of or in combination with software instructions. Therefore, the description herein is not limited to any particular combination of hardware circuitry and software.

[0138] As used herein, the terms “computer-readable medium” or “machine-readable medium” refer to any medium that participates in providing instructions to a processor PRO1 for execution. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical discs or magnetic disks, such as storage devices SD. Volatile media include dynamic memory, such as main memory MM. Transmission media include coaxial cables, copper wires, and optical fibers, including wires (which include buses BS). Transmission media can also take the form of sound waves or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media include, for example, floppy disks, floppy disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tape, any other physical media with a perforated pattern, RAM, PROMs and EPROMs, FLASH-EPROMs, any other memory chips or cartridges, carrier waves as described below, or any other medium from which a computer can read.

[0139] Various forms of computer-readable media can be used to carry one or more sequences of one or more instructions to the processor PRO1 for execution. For example, instructions may initially be carried on the disk of a remote computer. The remote computer can load the instructions into its dynamic memory and transmit them over a network such as the Internet. A modem local to the computer system CS can receive data and convert it into an infrared signal using an infrared transmitter. An infrared detector coupled to the bus BS can receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to the main memory MM, and the processor PRO1 retrieves and executes the instructions from the main memory MM. The instructions received by the main memory MM may optionally be stored on the storage device SD before or after execution by the processor PRO1.

[0140] The computer system CS may also include a communication interface CI coupled to the bus BS. The communication interface CI provides bidirectional data communication coupling with a network link NDL connected to a local area network (LAN). For example, the communication interface CI may be an Integrated Services Digital Network (ISDN) card or a modem to provide data communication connectivity to a corresponding type of telephone line. As another example, the communication interface CI may be a LAN card to provide data communication connectivity to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface CI transmits and receives electrical, electromagnetic, or optical signals carrying digital data streams representing various types of information.

[0141] A network link (NL) typically provides data communication to other data devices via one or more networks. For example, a network link (NL) can provide a connection via a local area network (LAN) to a host computer (HC) or a data device operated by an Internet service provider (ISP). The ISP, in turn, provides data communication services via a global packet data communication network (now commonly referred to as the "Internet" INT). Both LANs and the Internet INT use electrical, electromagnetic, or optical signals to carry digital data streams. Signals passing through various networks and signals on the network link (NL) and through the communication interface (CI) (which carries digital data to and from the computer system (CS)) are example forms of carriers for transmitting information.

[0142] The computer system CS can send messages and receive data including process code via networks (multiple), network data (NL), and communication interfaces (CI). In the Internet example, the server SV can transmit the requested code for an application via the Internet (INT), Internet Service Provider (ISP), Local Area Network (LAN), and communication interface (CI). For example, such a download application can provide all or part of the methods described herein. The received code can be executed by the processor PRO1 upon reception and / or stored in storage device SD or other non-volatile storage device for later execution. In this way, the computer system CS can obtain application code in carrier form.

[0143] Various embodiments of the system and method are disclosed in the subsequent list of numbered entries: 1. A mask-loaded lock, comprising: a loading lock chamber having a closure movable between an open position and a closed position, wherein when the closure is in the open position, a mask can be inserted into or removed from the chamber; a pump system configured to vent the chamber; a venting system configured to pressurize the chamber; a first valve having a variable-sized orifice and configured to communicate the pump system with the chamber; a second valve having a variable-sized orifice and configured to communicate the venting system with the chamber; and a controller operatively connected to the first valve and the second valve and configured to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile. 2. The mask loading lock according to any one of the preceding clauses further includes a pressure sensor operatively connected to the controller and configured to monitor the pressure inside the room and provide the controller with a pressure signal indicating the pressure inside the room. 3. A mask-mounted lock according to any one of the preceding clauses, wherein the controller controls the orifice size based on the pressure signal. 4. A mask loading lock according to any one of the preceding clauses, wherein the controller is pre-programmed to control the orifice size based on a predetermined pressure curve that varies over time. 5. A mask-mounted lock according to any one of the preceding clauses, wherein the mask includes a surface film, and wherein the mask is separated from the surface film by a small air gap. 6. A mask plate mounting lock according to any one of the preceding clauses, wherein the small air gap is between 50 μm and 1 mm wide. 7. A mask-mounted lock according to any one of the preceding clauses, wherein gas is vented from the chamber to create a vacuum environment. 8. The mask loading lock according to any one of the preceding clauses, wherein the controller is configured to control the second valve to allow gas to enter the chamber so that the chamber is in a non-vacuum environment. 9. A mask mounting lock according to any one of the preceding clauses, wherein the non-vacuum environment is at atmospheric pressure. 10. The mask loading lock according to any one of the preceding clauses, wherein the first valve and the second valve are servo-controlled valves with orifice size control. 11. A mask plate mounting lock according to any one of the preceding clauses, wherein the closure element is a gate valve. 12. A photolithography apparatus includes: an irradiation system that provides a radiation beam; a support structure that supports a photomask, wherein the photomask is configured to impart a pattern in its cross-section to the radiation beam; a substrate support that supports a substrate; a projection system that projects the patterned beam onto a target portion of the substrate; and a photomask loading lock, including: a loading lock chamber having a closure movable between an open position and a closed position, wherein when the closure is in the open position, the photomask can be inserted into or removed from the chamber; a pump system configured to vent the chamber; a venting system configured to pressurize the chamber; a first valve having a variable-sized orifice and configured to communicate the pump system with the chamber; a second valve having a variable-sized orifice and configured to communicate the venting system with the chamber; and a controller operatively connected to the first and second valves and configured to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile. 13. The lithography apparatus according to any one of the preceding clauses further includes a pressure sensor operatively connected to the controller and configured to monitor the pressure in the chamber and provide the controller with a pressure signal indicating the pressure in the chamber. 14. The lithography apparatus according to any one of the preceding clauses, wherein the controller controls the aperture size based on the pressure signal. 15. The lithography apparatus according to any one of the preceding clauses, wherein the controller is pre-programmed to control the aperture size based on a predetermined pressure curve that varies over time. 16. The photolithography apparatus according to any one of the preceding clauses, wherein the photomask includes a surface film, wherein the photomask is separated from the surface film by a small air gap. 17. The lithography apparatus according to any one of the preceding clauses, wherein the small air gap is between 50 μm and 1 mm wide. 18. The lithography apparatus according to any one of the preceding clauses, wherein the gas is vented from the chamber to create a vacuum environment in the chamber. 19. The lithography apparatus according to any one of the preceding clauses, wherein the controller is configured to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment. 20. The lithography apparatus according to any one of the preceding clauses, wherein the non-vacuum environment is at atmospheric pressure. 21. The lithography apparatus according to any one of the preceding clauses, wherein the first valve and the second valve are servo control valves with orifice size control. 22. The lithography apparatus according to any one of the preceding clauses, wherein the closure element is a gate valve. 23. A method of loading a lock using a mask, comprising: inserting or removing a mask into or from a closure of a lock chamber when the closure is in an open position, wherein the closure is movable between an open position and a closed position; evacuating the chamber using a pump system; pressurizing the chamber using a venting system; communicating the pump system to the chamber using a first valve having a variable-sized orifice; communicating the venting system to the chamber using a second valve having a variable-sized orifice; and controlling the size of the orifice using a controller operatively connected to the first and second valves to control the pressure in the chamber over time based on a desired pressure profile. 24. The method according to any one of the preceding clauses further includes monitoring the pressure in the room using a pressure sensor operatively connected to the controller, and using the pressure sensor to provide the controller with a pressure signal indicating the pressure in the room. 25. The method according to any one of the preceding clauses further includes using the controller to control the orifice size based on the pressure signal. 26. The method according to any one of the preceding clauses further includes pre-programming the controller to control the orifice size based on a predetermined pressure curve that varies over time. 27. The method according to any one of the preceding clauses, wherein the mask comprises a surface film, wherein the mask is separated from the surface film by a small air gap. 28. The method according to any one of the preceding clauses, wherein the small air gap is between 50 μm and 1 mm wide. 29. The method according to any one of the preceding clauses, wherein the gas is vented from the chamber to create a vacuum environment in the chamber. 30. The method according to any one of the preceding clauses further includes using the controller to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment. 31. The method according to any one of the preceding clauses, wherein the non-vacuum environment is at atmospheric pressure. 32. The method according to any one of the preceding clauses, wherein the first valve and the second valve are servo-controlled valves with orifice size control. 33. The method according to any one of the preceding clauses, wherein the closure element is a gate valve. 34. A method of loading a locking member using a mask, comprising: inserting a mask into a loading locking chamber via a closure member when the closure member is in an open position, wherein the closure member is movable between an open position and a closed position; venting the loading locking chamber by using a pump system and a first valve having a variable-sized orifice, and controlling the size of the orifice by using a controller operatively connected to the first valve to control the pressure in the chamber over time based on a desired pumping pressure curve; moving the mask from the loading locking chamber to a photolithography apparatus; exposing a substrate using a pattern of the mask in the photolithography apparatus; moving the mask from the photolithography apparatus to the loading locking chamber; venting the loading locking chamber by using a venting system and a second valve having a variable-sized orifice, and controlling the size of the orifice by using a controller operatively connected to the second valve to control the pressure in the chamber over time based on a desired venting pressure curve; and removing the mask from the loading locking chamber via the closure member when the closure member is in the open position. 35. The method according to any one of the preceding clauses further includes monitoring the pressure in the room using a pressure sensor operatively connected to the controller, and using the pressure sensor to provide the controller with a pressure signal indicating the pressure in the room. 36. The method according to any one of the preceding clauses further includes using the controller to control the orifice size based on the pressure signal. 37. The method according to any one of the preceding clauses further includes pre-programming the controller to control the orifice size based on a predetermined pressure curve that varies over time. 38. The method according to any one of the preceding clauses, wherein the mask includes a surface film, wherein the mask is separated from the surface film by a small air gap. 39. The method according to any one of the preceding clauses, wherein the small air gap is between 50 μm and 1 mm wide. 40. The method according to any one of the preceding clauses, wherein the gas is vented from the chamber to create a vacuum environment in the chamber. 41. The method according to any one of the preceding clauses further includes using the controller to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment. 42. The method according to any one of the preceding clauses, wherein the non-vacuum environment is at atmospheric pressure. 43. The method according to any one of the preceding clauses, wherein the first valve and the second valve are servo control valves with orifice size control. 44. The method according to any one of the preceding clauses, wherein the closure element is a gate valve.

[0144] The concepts disclosed herein can be associated with any general imaging system used for imaging subwavelength characteristics and are particularly applicable to emerging imaging techniques capable of generating increasingly shorter wavelengths. Emerging techniques already in use include EUV (Extreme Ultraviolet) and DUV lithography, with DUV lithography capable of generating 193 nm wavelengths using ArF lasers and even 157 nm wavelengths using fluorine lasers. Furthermore, EUV lithography can generate wavelengths in the 20–5 nm range by using synchrotrons or bombarding materials (solid-state or plasma) with high-energy electrons, thereby generating photons within this range.

[0145] While the concepts disclosed herein can be used for wafer fabrication on substrates such as silicon wafers, it should be understood that the disclosed concepts can also be used in any type of manufacturing system, such as systems for fabrication on substrates other than silicon wafers. Furthermore, combinations and sub-combinations of the disclosed elements can include individual embodiments. For example, cleaning systems and / or methods, along with associated lithography equipment, can include individual embodiments, and / or these features can be used together in the same embodiment.

[0146] The above description is intended to be illustrative only and not restrictive. Therefore, those skilled in the art will understand that modifications can be made in the described manner without departing from the scope of the claims set forth below.

Claims

1. A mask loading lock, comprising: A loading lock chamber, wherein the chamber has a closure movable between an open position and a closed position, wherein when the closure is in the open position, a mask can be inserted into or removed from the chamber; A pump system configured to empty the chamber; A ventilation system configured to pressurize the chamber; A first valve having a variable-sized orifice and configured to communicate the pump system with the chamber; A second valve, having a variable-sized orifice and configured to communicate the ventilation system with the chamber; as well as A controller, operatively connected to the first and second valves, is configured to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile.

2. The mask loading lock of claim 1 further includes a pressure sensor, the pressure sensor being operatively connected to the controller and configured to monitor the pressure inside the chamber and provide the controller with a pressure signal indicating the pressure inside the chamber, wherein: The controller controls the orifice size based on the pressure signal; and The controller is pre-programmed to control the orifice size based on a predetermined pressure curve that changes over time.

3. The mask plate loading lock according to claim 1, wherein: The mask includes a surface film, wherein the mask is separated from the surface film by a small air gap, the width of which is between 50 μm and 1 mm; The gas is vented from the chamber to create a vacuum environment in the chamber; The controller is configured to control the second valve to allow gas to enter the chamber, thereby creating a non-vacuum environment in the chamber; and The non-vacuum environment is at atmospheric pressure.

4. The mask plate loading lock according to claim 1, wherein: The first valve and the second valve are servo-controlled valves with orifice size control; and The closing element is a gate valve.

5. A photolithography apparatus, comprising: An irradiation system that provides a radiation beam; A support structure that supports a mask, wherein the mask is configured to impart a pattern in its cross-section to a radiating beam; A substrate support member that supports a substrate; A projection system that projects a patterned beam onto a target portion of the substrate; as well as Mask loading lock, including: A loading lock chamber, wherein the chamber has a closure movable between an open position and a closed position, wherein when the closure is in the open position, the mask can be inserted into or removed from the chamber; A pump system configured to empty the chamber; A ventilation system configured to pressurize the chamber; A first valve having a variable-sized orifice and configured to communicate the pump system with the chamber; A second valve, having a variable-sized orifice and configured to communicate the ventilation system with the chamber; and A controller, operatively connected to the first and second valves, is configured to control the size of the orifice to control the pressure in the chamber over time based on a desired pressure profile.

6. The lithography apparatus of claim 5, further comprising a pressure sensor operatively connected to the controller and configured to monitor the pressure in the chamber and provide the controller with a pressure signal indicating the pressure in the chamber, wherein: The controller controls the orifice size based on the pressure signal; and The controller is pre-programmed to control the orifice size based on a predetermined pressure curve that changes over time.

7. The photolithography apparatus according to claim 5, wherein: The mask includes a surface film, wherein the mask is separated from the surface film by a small air gap, the width of which is between 50 μm and 1 mm; The gas is vented from the chamber to create a vacuum environment in the chamber; The controller is configured to control the second valve to allow gas to enter the chamber, thereby creating a non-vacuum environment in the chamber; and The non-vacuum environment is at atmospheric pressure.

8. The photolithography apparatus according to claim 5, wherein: The first valve and the second valve are servo-controlled valves with orifice size control; and The closing element is a gate valve.

9. A method for loading a lock using a mask, comprising: When the closure of the loading lock chamber is in the open position, a mask is inserted into or removed from the closure, wherein the closure is movable between the open and closed positions; The chamber was emptied using a pump system; The chamber is pressurized using a ventilation system; The pump system is connected to the chamber using a first valve with a variable-sized orifice; The ventilation system is connected to the chamber using a second valve with a variable-sized orifice; and A controller, operably connected to the first and second valves, is used to control the size of the orifice in order to control the pressure in the chamber over time based on a desired pressure profile.

10. The method of claim 9, further comprising: The pressure in the room is monitored using a pressure sensor that is operatively connected to the controller, and a pressure signal indicating the pressure in the room is provided to the controller using the pressure sensor. The orifice size is controlled using the controller based on the pressure signal; as well as The controller is pre-programmed to control the orifice size based on a predetermined pressure curve that changes over time.

11. The method according to claim 9, wherein: The mask includes a surface film, wherein the mask is separated from the surface film by a small air gap, the width of which is between 50 μm and 1 mm; and The gas is vented from the chamber to create a vacuum environment in the chamber.

12. The method of claim 9, further comprising using the controller to control the second valve to allow gas to enter the chamber, thereby placing the chamber in a non-vacuum environment, wherein the non-vacuum environment is at atmospheric pressure.

13. The method according to claim 9, wherein: The first valve and the second valve are servo-controlled valves with orifice size control; and The closing element is a gate valve.

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