Lithographic apparatuses, reticle cooling apparatuses and related methods

Abstract

This invention provides a system, apparatus, and method for removing heat from a 1x magnifying glass. One example method may include generating a cooling control signal by a cooling controller based on timing data for a projection of a patterned radiation beam, absorption data for an exposed area, and a target heat transfer rate formed by irradiating the exposed area on a 1x magnifying glass supported by a 1x magnifying glass stage. The cooling control signal may instruct a 1x magnifying glass cooling device to actuate actuators to modify a distance between the 1x magnifying glass and a top of the 1x magnifying glass cooling device. The method may further include modifying the distance between the 1x magnifying glass and the top based on the cooling control signal using the actuators to modify a heat transfer rate associated with the removal of heat from the 1x magnifying glass to the target heat transfer rate.

Description

[Technical Field]

[0001] This invention relates to lithography equipment, and more specifically, to heat removal of a magnifying mask used in lithography equipment. [Previous Technology]

[0002] A lithography apparatus is a machine that applies a desired pattern to a substrate (typically to a target portion of the substrate). Lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device (which is interchangeably referred to as a mask or magnifying mask) can be used to generate a circuit pattern to be formed on a single layer of the IC being formed. This pattern can be transferred to a target portion (e.g., a portion including a die, a die, or several dies) on a substrate (e.g., a silicon wafer). The transfer of the pattern is typically performed by imaging onto a radiation-sensitive material (e.g., a resist) layer provided on the substrate. Generally, a single substrate will contain a network of continuously patterned adjacent target portions. Traditional lithography equipment includes: a so-called stepper, which irradiates target areas by exposing the entire pattern onto the target area at once; and a so-called scanner, which irradiates target areas by scanning the pattern with a radiation beam in a given direction ("scanning" direction) while simultaneously scanning the target areas parallel or antiparallel (e.g., opposite) to this scanning direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0003] As semiconductor manufacturing processes continue to advance, the size of circuit components has been shrinking for decades, while the number of functional components, such as transistors, per device has been steadily increasing, following a trend commonly known as "Moore's Law." To comply with Moore's Law, the semiconductor industry is pursuing technologies that enable the generation of increasingly smaller features. Photolithography equipment uses electromagnetic radiation to project patterns onto a substrate. The wavelength of this radiation determines the minimum size of the feature patterned on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0004] Extreme ultraviolet (EUV) radiation, such as electromagnetic radiation (sometimes referred to as soft X-rays) with wavelengths of about 50 nanometers (nm) or smaller, including light with wavelengths of about 13.5 nm, can be used in or with lithography equipment to create extremely small features in or on substrates such as silicon wafers. Compared to lithography equipment using radiation with wavelengths of, for example, 193 nm, lithography equipment using EUV radiation with wavelengths in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on substrates.

[0005] Methods for generating EUV light include, but are not limited to, converting materials having emission spectral lines in the EUV range (e.g., xenon (Xe), lithium (Li), or tin (Sn)) into a plasma state. For example, in one such method known as laser-generated plasma (LPP), plasma can be generated by irradiating a target material, such as a droplet, plate, strip, stream, or cluster of material, with an amplified beam, which may be called a driving laser. In the context of the LPP source, the target material is interchangeably referred to as fuel. For this procedure, plasma is typically generated in a sealed container, such as a vacuum chamber, and various types of metrological equipment are used to monitor the plasma.

[0006] The radiation beam used to project a pattern placed on a magnifying mask onto a substrate will deliver a large amount of heat to the magnifying mask. The localized expansion of the magnifying mask caused by heating can reduce the accuracy of the projected pattern overlaying the pattern already existing on the substrate. [Summary of the Invention]

[0007] This invention describes various systems, devices, and methods for removing heat from a photomask during operation of a lithography apparatus, thereby improving the accuracy of projected patterns overlaying patterns already existing on a substrate.

[0008] In some embodiments, the present invention describes a lithography apparatus. The lithography apparatus may include an optical system configured to guide a radiation beam onto a magnifying mask supported by a magnifying mask stage to form a patterned radiation beam. The radiation beam may cause heating of exposed areas of the magnifying mask. The lithography apparatus may further include a magnifying mask cooling device configured to remove heat from the magnifying mask. The magnifying mask cooling device may include a cooling element disposed below the magnifying mask and adjacent to the exposed area. The cooling element may include a body comprising a chamber connected to a channel configured to deliver gas to a chamber. The top of the chamber may be disposed adjacent to the magnifying mask and may include an opening configured to output gas toward the magnifying mask. The magnifying mask cooling device may further include an actuator configured to modify the distance between the top and the magnifying mask. The photomask cooling device may further include a cooling controller configured to generate a cooling control signal based on timing data for the projection of the patterned radiation beam, absorption data for the exposed area on the photomask, and a target heat transfer rate. The cooling control signal may be configured to instruct the photomask cooling device to actuate an actuator to modify the distance between the top and the photomask. The cooling controller may be further configured to transmit the cooling control signal to the actuator.

[0009] In some embodiments, the present invention describes a photomask cooling device. The photomask cooling device may include a cooling element configured to be positioned below and adjacent to an exposed area of ​​a photomask supported by a photomask stage. The cooling element may include a body containing a chamber connected to a channel configured to deliver gas to a chamber. The top of the chamber may be configured to be positioned adjacent to the photomask and may include an opening configured to output gas toward the photomask. The photomask cooling device may further include an actuator configured to modify the distance between the top and the photomask. The photomask cooling device may further include a cooling controller configured to generate a cooling control signal based on timing data for the projection of a patterned radiation beam generated by the photomask, absorption data for the exposed area on the photomask, and a target heat transfer rate. The cooling control signal can be configured to instruct the actuator of the photomask cooling device to modify the distance between the top and the photomask. The cooling controller can be further configured to transmit the cooling control signal to the actuator.

[0010] In some embodiments, the present invention describes a method for removing heat from a self-reducing photomask. The method may include generating a cooling control signal by a cooling controller based on timing data for the projection of a patterned radiation beam (formed by irradiating an exposed area on a photomask supported by a photomask stage), absorption data for the exposed area, and a target heat transfer rate. The cooling control signal may instruct a photomask cooling device to actuate an actuator to modify the distance between the photomask and the top of a chamber connected to a channel for delivering gas to the chamber. The channel may be disposed in the body of a cooling element of the photomask cooling device. The method may further include transmitting the cooling control signal to the actuator by the cooling controller. The method may further include modifying the distance between the photomask and the top by the actuator based on the cooling control signal to modify the heat transfer rate associated with heat removal from the photomask to a target heat transfer rate.

[0011] Other features, structures, and operations of various forms are described in detail below with reference to the accompanying drawings. It should be noted that the invention is not limited to the specific forms described herein. Such forms are presented herein for illustrative purposes only. Additional forms will become apparent to those skilled in the art based on the teachings contained herein.

Implementation Method

[0027] This specification discloses one or more embodiments that possess the features of the present invention. The disclosed embodiments are merely illustrative of the invention. The scope of the invention is not limited to the disclosed embodiments. The breadth and scope of the invention are defined by the appended claims and their equivalents.

[0028] The embodiments described herein and the references to "an embodiment," "an example embodiment," etc., in this specification may include a specific feature, structure, or characteristic, but different embodiments may not necessarily include that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be understood that, whether explicitly described or not, implementing this feature, structure, or characteristic in conjunction with other embodiments is within the understanding of those skilled in the art.

[0029] For ease of description, spatial relative terms such as “below,” “under,” “lower,” “above,” “upper,” “upper,” etc., are used herein to describe the relationship between one element or feature and another, as illustrated in the figures. In addition to the orientations depicted in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein will be interpreted accordingly.

[0030] As used herein, the term "about" indicates a given quantity of value that may vary based on a particular technique. Based on a particular technique, the term "about" may indicate a given quantity of value that varies, for example, within 10% to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0031] Overview

[0032] In one example, the magnification mask in an EUV scanner can be heated by absorbing EUV radiation and cooled via a water-cooled magnification mask fixture. For a source with a power greater than approximately 500 W, the absorption can be, for example, approximately 100 watts (W). However, indirect cooling via a water-cooled magnification mask stage can be inefficient and requires a water connection to a rapidly moving magnification mask fixture, which can impair electromechanical integration performance. Furthermore, the thermal resistance of a thick magnification mask can cause a relatively slow cooling response and first wafer effect. Additionally, material inhomogeneity can limit the effectiveness of feedforward software correction. Moreover, a large thermal gradient through the magnification mask can limit the effectiveness of back-side cooling via the magnification mask fixture.

[0033] In contrast, some embodiments of the present invention provide a photomask cooling shroud having a cooling plate that is brought close to the surface of the photomask adjacent to an EUV radiation beam in the scanning direction (e.g., the Y direction) by a forced flow of cold air. In some embodiments, scanning motion can cause dynamic heating (e.g., in the EUV radiation beam) and cooling (e.g., away from the beam above the cooling plate), which can be balanced to approximately 0 W by tuning cooling parameters based on EUV absorption (e.g., which can be derived from end-user operation data or measured in situ). In some embodiments, the photomask cooling shroud described herein can be positioned between the photomask and the photomask shielding (ReMa) Y-shaped blades in a scanning EUV lithography apparatus. In some embodiments, the photomask cooling shroud described herein can be operated using hydrogen (H2) at a separation distance between approximately 50 micrometers and approximately 100 micrometers from the surface of the photomask. In some cases, the reticle cooling device described in this article may also be referred to as a "reticle cooling hood".

[0034] In some embodiments, the present invention provides heat removal from a photomask by means of the following operation: as an initial operation, a cooling control signal is generated based on timing data for the projection of a patterned radiation beam (the patterned radiation beam is formed by irradiating an exposed area on a photomask supported by a photomask stage), absorption data for the exposed area, and a target heat transfer rate. In some embodiments, the present invention further provides transmitting the cooling control signal to a photomask cooling shroud to instruct a set of actuators (e.g., one or more actuators) to modify the distance between the photomask and the photomask cooling shroud. In some embodiments, the present invention provides modifying the distance between the photomask and the photomask cooling shroud using the set of actuators and based on the cooling control signal to modify the heat transfer rate associated with heat removal from the photomask to a target heat transfer rate.

[0035] In some embodiments, the reticle cooling shroud described herein may include any combination or sub-combination of the components, structures, features, and technologies described herein: U.S. Patent No. 10,747,127, issued August 18, 2020, entitled "Lithographic apparatus"; U.S. Patent No. 10,416,574, issued September 17, 2019, entitled "Lithographic apparatus"; U.S. Patent No. 6,445,439, issued September 3, 2002, entitled "EUV reticle thermal management"; each of these patents is incorporated herein by reference in its entirety. In some embodiments, the photomask cooling hood described herein, superior to the wafer cooling techniques described in one or more of these references, can offer reduced complexity and thus lower costs and improved reliability. This is because the movement of the photomask stage is less complex than that of the wafer stage (e.g., the photomask stage can scan only in the Y direction, while the wafer stage can step in both the X and Y directions), and the thermal requirements of the low thermal expansion material (LTEM) photomask substrate are less stringent than those of the wafer substrate. Furthermore, the photomask may not be coated with a degassing resist, thus thermal coupling is more stable at this location, and H2 can be used with reduced effects from thermal adaptability (TAC) variations. Alternatively or concurrently, the usable volume at the photomask level is larger than that at the wafer level due to many dimensions being approximately four times larger and having less conflicting functions (e.g., little or no need for Z-mirrors and dynamic gas locks (DGL)).

[0036] In some cases, the cooling technique for the phasing mask described herein can also be achieved by zero cross-displacement of the phasing mask material. However, this may require preheating the phasing mask to achieve overlay improvement and to update the phasing mask writing and quality assessment infrastructure to correct for errors during phasing mask writing and quality assessment.

[0037] Numerous exemplary embodiments exist of the systems, apparatuses, methods, and computer programs disclosed herein. For example, the phasing mask cooling hood described herein does not require active position control (e.g., reducing the complexity of mechanical and volumetric considerations, even when such active position control is practically possible). In some embodiments, the substantial elimination of active position control may be achieved by positioning it for higher source power (e.g., greater than about 800 W) of stacking gain, or by positioning it as an opening to significantly reduce the complexity of the phasing mask stage by removing the water cooling line from the dynamic interface to the fast scanning stage. In some embodiments, the substantial elimination of active position control may also extend the maximum scanning speed and acceleration achievable by the phasing mask stage (e.g., in the positive and negative Y directions).

[0038] However, it is beneficial to present an example environment in which the present invention can be implemented before describing such a pattern in more detail.

[0039] Example Microfilm System

[0040] Figures 1A and 1B are schematic illustrations of the lithography apparatus 100 and 100', respectively, which are embodiments of the present invention. As shown in Figures 1A and 1B, the lithography apparatus 100 and 100' are illustrated from a perspective (e.g., a side view) perpendicular to the XZ plane (e.g., the X-axis points to the right, the Z-axis points upward, and the Y-axis points inward from the viewer on the page), while the patterned device MA and the substrate W are presented from an additional perspective (e.g., a top view) perpendicular to the XY plane (e.g., the X-axis points to the right, the Y-axis points upward, and the Z-axis points outward from the viewer on the page).

[0041] In some embodiments, lithography apparatus 100 and / or lithography apparatus 100' may include one or more of the following structures: an irradiation system IL (e.g., an irradiator) configured to modulate a radiation beam B (e.g., a deep ultraviolet (DUV) radiation beam or an extreme ultraviolet (EUV) radiation beam); a support structure MT (e.g., a mask stage, a photomask stage) configured to support a patterning device MA (e.g., a mask, a photomask, or a dynamic patterning device) and connected to a first positioner PM configured to accurately position the patterning device MA; and a substrate holder (such as a substrate stage WT (e.g., a wafer stage)) configured to hold a substrate W (e.g., a resist-coated wafer) and connected to a second positioner PW configured to accurately position the substrate W. Lithography devices 100 and 100' also include a projection system PS (e.g., a refractive projection lens system) configured to project a pattern imparted by a patterning device MA to a radiating beam B onto a target portion C (e.g., a portion comprising one or more grains) of a substrate W. In lithography device 100, the patterning device MA and the projection system PS are reflective. In lithography device 100', the patterning device MA and the projection system PS are transmissive.

[0042] In some embodiments, during operation, the irradiation system IL may receive a radiated beam from a radiation source SO (e.g., via a beam delivery system BD shown in FIG. 1B). The irradiation system IL may include various types of optical components for guiding, shaping, or controlling the radiation, such as refractive, reflective, reflective-refractive, magnetic, electromagnetic, electrostatic, and other types of optical components, or any combination thereof. In some embodiments, the irradiation system IL may be configured to adjust the radiated beam B to have a desired spatial and angular intensity distribution in its cross-section at the plane of the patterned device MA.

[0043] In some embodiments, the support structure MT may hold the patterned device MA in a manner dependent on the orientation of the patterned device MA relative to the reference frame, the design of at least one of the lithography devices 100 and 100', and other conditions such as whether the patterned device MA is held in a vacuum environment. The support structure MT may use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterned device MA. The support structure MT may be a frame or a stage, for example, which may be fixed or movable as needed. By using sensors, the support structure MT can ensure that the patterned device MA is, for example, in the desired position relative to the projection system PS.

[0044] The term "patterning device" MA should be broadly interpreted to refer to any device that can be used to impart a pattern to a radiation beam B in its cross-section 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 device, which is generated in the target portion C to form an integrated circuit.

[0045] In some configurations, the patterning device MA can be transmissive (as in the lithography device 100' of FIG. 1B) or reflective (as in the lithography device 100 of FIG. 1A). The patterning device MA can include various structures, such as a magnifying mask, a mask, a programmable mirror array, a programmable LCD panel, other suitable structures, or combinations thereof. The mask can include mask types such as binary, alternating phase shift, or attenuation phase shift, as well as various hybrid mask types. In one example, the programmable mirror array can include a matrix configuration of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors can impart a pattern to the radiation beam B reflected by the matrix of small mirrors.

[0046] The term "projection system" PS should be interpreted broadly and may encompass any type of projection system suitable for exposure to radiation and / or for use with a wetted liquid (e.g., on a substrate W) or a vacuum, including refractive, reflective, reflective-refractive, magnetic, synthetic, electromagnetic, and electrostatic optical systems, or any combination thereof. A vacuum environment may be used for EUV or electron beam radiation because other gases may absorb excessive radiation or electrons. A vacuum environment can therefore be provided throughout the beam path by means of vacuum walls and a vacuum pump. Furthermore, in some instances, any use of the term "projection lens" herein may be interpreted as synonymous with the more general term "projection system" PS.

[0047] In some embodiments, lithography apparatus 100 and / or lithography apparatus 100' may be of the type having two (e.g., "dual stages") or more two substrate stages (e.g., two or more of substrate stages WT) and / or two or more two reduction mask stages (e.g., two or more of support structures MT). In such "multi-stage" machines, additional substrate stages WT can be used in parallel, or preparatory steps can be performed on one or more stages while one or more other substrate stages WT are used for exposure. In one example, a preparatory step for subsequent exposure of substrate W can be performed on substrate W positioned on one of the substrate stages WT, while another substrate W positioned on the other substrate stage WT is used to expose a pattern onto the other substrate W. In some embodiments, the additional stage may not be a substrate stage WT.

[0048] In some embodiments, in addition to the substrate stage WT, the lithography apparatus 100 and / or the lithography apparatus 100' may include a measurement stage. The measurement stage may be configured to hold sensors. The sensors may be configured to measure properties of the projection system PS, properties of the radiation beam B, or both. In some embodiments, the measurement stage may hold multiple sensors. In some embodiments, the measurement stage may move below the projection system PS when the substrate stage WT is away from the projection system PS.

[0049] In some embodiments, lithography apparatus 100 and / or lithography apparatus 100' may also be of the type in which at least a portion of the substrate is covered by a liquid (e.g., water) having a relatively high refractive index to fill the space between the projection system PS and the substrate W. A wetting liquid may also be applied to other spaces within the lithography apparatus, such as the space between the patterned device MA and the projection system PS. Immersion techniques are used to increase the numerical aperture of the projection system. The term "immersion" as used herein does not mean that a structure such as the substrate must be submerged in the liquid, but only that the liquid is positioned between the projection system and the substrate during exposure. Various immersion techniques are described in U.S. Patent No. 6,952,253, issued October 4, 2005, entitled "LITHOGRAPHIC APPARATUS AND DEVICE MANUFACTURING METHOD," which is incorporated herein by reference in its entirety.

[0050] Referring to Figures 1A and 1B, the irradiation system IL receives a radiation beam B from a radiation source SO. For example, when the radiation source SO is an excimer laser, the radiation source SO and the lithography device 100 or 100' may be separate physical entities. In such cases, the radiation source SO is not considered part of the lithography device 100 or 100', and the radiation beam B is delivered from the radiation source SO to the irradiation system IL by means of a beam delivery system BD (e.g., shown in Figure 1B) including, for example, suitable guide mirrors and / or beam expanders. In other cases, such as when the radiation source SO is a mercury lamp, the radiation source SO may be an integral part of the lithography device 100 or 100'. The radiation source SO and the irradiator IL may (if necessary) be referred to together with the beam delivery system BD as the radiation system.

[0051] In some embodiments, the illumination system IL may include an adjuster AD for adjusting the angular intensity distribution of the radiated beam. Typically, at least the outer radial range and / or inner radial range (typically referred to as "σ outer" and "σ inner," respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. Furthermore, the illumination system IL may include various other components, such as a condenser IN and a radiation collector CO (e.g., a condenser or collector optics). In some embodiments, the illumination system IL may be used to adjust the radiated beam B to have a desired uniformity and intensity distribution in its cross-section.

[0052] Referring to FIG. 1A, in operation, the radiating beam B may be incident on a patterning device MA (e.g., a mask, a photomask, a programmable mirror array, a programmable LCD panel, any other suitable structure or combination thereof), which may be held on a support structure MT (e.g., a photomask stage) and may be patterned by a pattern (e.g., a design layout) presented on the patterning device MA. In the lithography apparatus 100, the radiating beam B may be reflected from the patterning device MA. In the case that has traversed the patterning device MA (e.g., after being reflected from the patterning device), the radiating beam B may pass through a projection system PS, which may focus the radiating beam B onto a target portion C of the substrate W or onto a sensor disposed at the stage.

[0053] In some configurations, the substrate stage WT can be accurately moved, for example, to position different target portions C in the path of the radiation beam B, by means of a second positioner PW and a position sensor IFD2 (e.g., an interferometric device, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor IFD1 (e.g., an interferometric device, a linear encoder, or a capacitive sensor) can be used to accurately position the patterned device MA relative to the path of the radiation beam B.

[0054] In some configurations, mask alignment marks M1 and M2 and substrate alignment marks P1 and P2 can be used to align the patterned device MA and the substrate W. Although Figures 1A and 1B illustrate substrate alignment marks P1 and P2 as occupying dedicated target portions, substrate alignment marks P1 and P2 can be positioned in the space between target portions. When substrate alignment marks P1 and P2 are positioned between target portions C, these substrate alignment marks are referred to as kerf alignment marks. Substrate alignment marks P1 and P2 can also be configured in the target portion C region as in-die marks. These in-die marks can also be used, for example, as metrological marks for overlay measurement.

[0055] In some cases, for illustrative and not limiting purposes, one or more of the figures herein may utilize the Cartesian coordinate system. The Cartesian coordinate system comprises three axes: the X-axis, the Y-axis, and the Z-axis. Each of the three axes is orthogonal to the other two axes (e.g., the X-axis is orthogonal to both the Y-axis and the Z-axis, the Y-axis is orthogonal to both the X-axis and the Z-axis, and the Z-axis is orthogonal to both the X-axis and the Y-axis). Rotation about the X-axis is called Rx rotation. Rotation about the Y-axis is called Ry rotation. Rotation about the Z-axis is called Rz rotation. In some cases, the X-axis and Y-axis define a horizontal plane, while the Z-axis is in the vertical direction. In some cases, the orientation of the Cartesian coordinate system may be different, for example, such that the Z-axis has a component along the horizontal plane. In some cases, another coordinate system, such as a cylindrical coordinate system, may be used.

[0056] Referring to FIG. 1B, the radiating beam B is incident on a patterned device MA held on a support structure MT, and is patterned by the patterned device MA. Having traversed the patterned device MA, the radiating beam B passes through a projection system PS, which focuses the beam onto a target portion C of the substrate W. In some embodiments, the projection system PS may have a pupil conjugate with the pupil of the illumination system. In some embodiments, the radiated portion may diverge from the intensity distribution at the pupil of the illumination system and traverse the mask pattern without being affected by diffraction at the mask pattern MP, thus producing an image of the intensity distribution at the pupil of the illumination system.

[0057] The projection system PS projects an image MP' of a mask pattern MP onto a resist layer coated on a substrate W, wherein the image MP' is formed by radiation of its own intensity distribution from a diffracted beam generated from the mask pattern MP. For example, the mask pattern MP may include a linear and spatial array. At the array, radiation diffracts a diffracted beam, different from zero-order diffraction, which has a change of direction in a direction perpendicular to the line. The reflected light (e.g., a zero-order diffracted beam) traverses the pattern without any change in its propagation direction. The zero-order diffracted beam traverses an upper lens or upper lens group upstream of the pupil conjugate of the projection system PS to reach the pupil conjugate. The portion of the intensity distribution in the plane of the pupil conjugate and associated with the zero-order diffracted beam is an image of the intensity distribution in the pupil of the illumination system IL. In some embodiments, the aperture device may be positioned or substantially located in the plane including the pupil conjugate of the projection system PS.

[0058] The projection system PS is configured to capture not only a zero-order diffracted beam, but also a first-order or higher-order diffracted beam (not shown) by means of a lens or lens group. In some embodiments, dipole illumination can be used to image a line pattern extending in a direction perpendicular to the line to utilize the resolution enhancement effect of dipole illumination. For example, a first-order diffracted beam interferes with a corresponding zero-order diffracted beam at a level on the substrate W to produce an image of a mask pattern MP at the highest possible resolution and program window (e.g., the available depth of focus combined with an allowable exposure dose deviation). In some embodiments, astigmatic aberration can be reduced by providing a radiating pole (not shown) in the opposite conjugate of the illumination system pupil. Furthermore, in some embodiments, astigmatic aberration can be reduced by blocking the zero-order beam in the pupil conjugate of the projection system PS associated with the radiating pole in the opposite conjugate. This is described in more detail in U.S. Patent No. 7,511,799, issued on March 31, 2009, entitled “LITHOGRAPHIC PROJECTION APPARATUS AND A DEVICE MANUFACTURING METHOD,” which is incorporated herein by reference in its entirety.

[0059] In some configurations, the substrate stage WT can be accurately moved, for example, to position different target portions C at focused and aligned positions in the path of the radiation beam B, by means of a second positioner PW and a position measurement system PMS (e.g., a position sensor including an interferometric device, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor (e.g., an interferometric device, a linear encoder, or a capacitive sensor) (not shown in FIG. 1B) can be used to accurately position the patterned device MA relative to the path of the radiation beam B (e.g., after mechanical capture from a mask library or during scanning). Mask alignment marks M1 and M2 and substrate alignment marks P1 and P2 can be used to align the patterned device MA and the substrate W.

[0060] Generally, the movement of the support structure MT can be achieved by means of a long-stroke positioner (coarse positioning) and a short-stroke positioner (fine positioning) forming part of the first positioner PM. Similarly, the movement of the substrate stage WT can be achieved by means of a long-stroke positioner and a short-stroke positioner forming part of the second positioner PW. In the case of a stepper (relative to a scanner), the support structure MT may be connected only to the short-stroke actuator, or it may be fixed. The patterned device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. Although the substrate alignment marks (as described) occupy a dedicated target portion, they can be positioned in the space between the target portions (e.g., kerf alignment marks). Similarly, in the case where more than one die is disposed on the patterned device MA, the mask alignment marks M1 and M2 can be positioned between the dies.

[0061] The support structure MT and the patterned device MA can be located within a vacuum chamber V, where an in-vacuum robot can be used to move patterned devices, such as masks, into and out of the vacuum chamber. Alternatively, when the support structure MT and the patterned device MA are located outside the vacuum chamber, an out-of-vacuum robot, similar to the in-vacuum robot, can be used for various transport operations. In some cases, it is necessary to calibrate both the in-vacuum and out-of-vacuum robots to smoothly transfer any payload (e.g., a mask) to a stationary motion mount.

[0062] In some configurations, the lithography devices 100 and 100' can be used in at least one of the following configurations:

[0063] 1. In the stepping mode, the support structure MT and the substrate stage WT remain substantially stationary, while the entire pattern applied to the radiation beam B is projected onto the target portion C in a single step (e.g., single static exposure). Subsequently, the substrate stage WT is shifted in the X and / or Y directions, allowing different target portions C to be exposed.

[0064] 2. In the scanning mode, the support structure MT and the substrate stage WT are scanned synchronously, and the pattern applied to the radiation beam B is projected onto the target portion C (e.g., single dynamic exposure). The speed and direction of the substrate stage WT (e.g., wafer stage) relative to the support structure MT (e.g., a magnified mask stage) can be determined by the (reduction) magnification and image inversion characteristics of the projection system PS.

[0065] 3. In another mode, the support structure MT remains substantially stationary, thereby holding the programmable patterning device MA, while the substrate stage WT moves or scans, simultaneously projecting the pattern imparted to the radiation beam B onto the target portion C. A pulsed radiation source SO can be used, and the programmable patterning device can be updated as needed after each movement of the substrate stage WT or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography using programmable patterning devices MA (such as programmable mirror arrays).

[0066] In some cases, the lithography devices 100 and 100' may adopt a combination and / or a variation or a completely different usage mode of the above-mentioned usage modes.

[0067] In some embodiments, as shown in FIG1A, the lithography apparatus 100 may include an EUV source configured to generate an EUV radiation beam B for EUV lithography. Generally, the EUV source may be configured in a radiation source SO, and the corresponding irradiation system IL may be configured to adjust the EUV radiation beam B of the EUV source.

[0068] Figure 2 shows the lithography device 100 (or its modified architecture) in more detail, which includes a radiation source SO (e.g., a source collector device), an illumination system IL, and a projection system PS. As shown in Figure 2, the lithography device 100 is illustrated from a perspective (e.g., a side view) perpendicular to the XZ plane (e.g., the X-axis points to the right and the Z-axis points upward).

[0069] The radiation source SO is constructed and configured such that a vacuum environment can be maintained within the enclosure structure 220. The radiation source SO includes a source chamber 211 and a collector chamber 212, and is configured to generate and transmit EUV radiation. EUV radiation can be generated by a gas or vapor, such as xenon (Xe) gas, lithium (Li) vapor, or tin (Sn) vapor, wherein an EUV radiation emitting plasma 210 is generated to emit radiation in the EUV range of the electromagnetic spectrum. The EUV radiation emitting plasma 210, which is at least partially ionized, can be generated by, for example, a discharge or a laser beam. A partial pressure of, for example, about 10.0 Pascals (Pa) of Xe gas, Li vapor, Sn vapor, or any other suitable gas or vapor can be used to efficiently generate radiation. In some cases, an excited tin plasma is provided to generate EUV radiation.

[0070] Radiation emitted by EUV radiation-emitting plasma 210 is transmitted from source chamber 211 to collector chamber 212 via a gas barrier or contaminant trap 230 (e.g., in some cases also referred to as a contaminant barrier or foil trap) positioned in or behind an opening in source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap 230 further indicated herein includes at least a channel structure.

[0071] Collector chamber 212 may include a radiation collector CO (e.g., a concentrator or collector optics) that may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation traversing the radiation collector CO may be reflected from the grating spectral filter 240 to be focused into a virtual source point IF. The virtual source point IF is often referred to as the intermediate focus, and the source collector device is configured such that the virtual source point IF is located at or near an opening 219 in the enclosure structure 220. The virtual source point IF is an image of the EUV radiation-emitting plasma 210. The grating spectral filter 240 may be used to suppress infrared (IR) radiation.

[0072] Subsequently, radiation traverses the illumination system IL, which may include a faceted field mirror device 222 and a faceted pupil mirror device 224. The faceted field mirror device and the faceted pupil mirror device are configured to provide the desired angular distribution of the radiation beam 221 at the patterned device MA and the desired uniformity of the radiation intensity at the patterned device MA. When the radiation beam 221 is reflected at the patterned device MA held by the support structure MT, a patterned beam 226 is formed, and the patterned beam 226 is imaged by the projection system PS onto the substrate W held by the wafer stage or substrate stage WT via reflective elements 228 and 229.

[0073] The illumination system IL and projection system PS may typically contain more elements than are shown. Depending on the type of lithography equipment, the grating spectral filter 240 may be present. Furthermore, there may be more mirrors than shown in Figure 2. For example, the projection system PS may contain one to six additional reflective elements than shown in Figure 2.

[0074] The radiation collector CO illustrated in Figure 2 is depicted as a nested collector with grazing incidence reflectors 253, 254, and 255, merely as an example of a collector (or collector mirror). The grazing incidence reflectors 253, 254, and 255 are arranged symmetrically about the optical axis O, and this type of radiation collector CO is preferably used in conjunction with a discharge-generating plasma (DPP) source.

[0075] Example Microfilm Unit

[0076] Figure 3 illustrates a lithocell 300, which is sometimes also referred to as a lithocell or cluster. As shown in Figure 3, the lithocell 300 is illustrated from a view (e.g., a top view) perpendicular to the XY plane (e.g., the X-axis points to the right and the Y-axis points upward).

[0077] The lithography apparatus 100 or 100' may form part of the lithography unit 300. The lithography unit 300 may also include one or more devices to perform pre-exposure and post-exposure processes on a substrate. For example, such devices may include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a cooling plate CH, and a baking plate BK. A substrate handler RO (e.g., a robot) picks up a substrate from input / output ports I / O1 and I / O2, moves the substrate between different process devices, and delivers the substrate to the loading area LB of the lithography apparatus 100 or 100'. These devices, often collectively referred to as the coating and developing system, are under the control of a coating and developing system control unit TCU, which is itself controlled by a supervisory control system SCS, which in turn controls the lithography apparatus via a lithography control unit LACU. Thus, different devices can be operated to maximize output and processing efficiency.

[0078] Example of a radiation source

[0079] Figure 4 shows an example of a radiation source SO used in an example reflective lithography device (e.g., lithography device 100 of Figure 1A). As shown in Figure 4, the radiation source SO is illustrated from a view perpendicular to the XY plane (e.g., a top view), as described below.

[0080] The radiation source SO shown in Figure 4 belongs to the type that can be called a laser-generated plasma (LPP) source. A laser system 401 (which may include, for example, a carbon dioxide (CO2) laser) is configured to deposit energy onto fuel targets 403' (such as one or more discrete tin (Sn) droplets) via one or more laser beams 402, which are provided by a fuel target generator 403 (e.g., a fuel emitter, droplet generator). Depending on some configurations, the laser system 401 may be a pulsed, continuous-wave, or quasi-continuous-wave laser, or may operate in a manner consistent with the foregoing. The trajectory of the fuel target 403' (e.g., droplets) emitted from the fuel target generator 403 may be parallel to the X-axis. Depending on some configurations, one or more laser beams 402 propagate in a direction parallel to the Y-axis, which is perpendicular to the X-axis. The Z-axis is perpendicular to both the X and Y axes and typically extends into (or outside) the plane of the page, but in other configurations, other configurations are used. In some embodiments, the laser beam 402 may propagate in a direction other than parallel to the Y-axis (e.g., in a direction other than orthogonal to the X-axis direction of the trajectory of the fuel target 403').

[0081] In some configurations, one or more laser beams 402 may include a pre-pulse laser beam and a main-pulse laser beam. In these configurations, the laser system 401 may be configured to use the pre-pulse laser beam to impact each of the fuel targets 403' to generate a modified fuel target. The laser system 401 may be further configured to use the main-pulse laser beam to impact each of the modified fuel targets to generate plasma 407.

[0082] Although tin is mentioned in the following description, any suitable target material may be used. The target material may be, for example, in liquid form and may be, for example, a metal or alloy. The fuel target generator 403 may include a nozzle configured to guide tin along a trajectory toward the plasma formation region 404, for example, in the form of a fuel target 403' (e.g., discrete droplets). Throughout the remainder of the description, references to "fuel," "fuel target," or "fuel droplets" should be understood to refer to the target material (e.g., droplets) emitted by the fuel target generator 403. The fuel target generator 403 may include a fuel emitter. One or more laser beams 402 are incident on the target material (e.g., tin) at the plasma formation region 404. The deposition of laser energy in the target material generates plasma 407 at the plasma formation region 404. During the de-excitation and recombination of ions and electrons in the plasma, radiation, including EUV radiation, is emitted from the plasma 407.

[0083] EUV radiation is collected and focused by radiation collector 405 (e.g., radiation collector CO). In some embodiments, radiation collector 405 may comprise a near-normal incident radiation collector (sometimes more commonly referred to as a normal incident radiation collector). Radiation collector 405 may be a multilayer structure configured to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as about 13.5 nm). According to some embodiments, radiation collector 405 may have an elliptical configuration with two focal points. As discussed herein, the first focal point may be located at plasma forming region 404, and the second focal point may be located at intermediate focal point 406.

[0084] In some configurations, the laser system 401 may be positioned at a relatively long distance from the radiation source SO. In this case, one or more laser beams 402 may be delivered from the laser system 401 to the radiation source SO by means of a beam delivery system (not shown) including, for example, suitable guide mirrors and / or beam expanders and / or other optics. The laser system 401 and the radiation source SO may be considered together as a radiation system.

[0085] Radiation reflected by radiation collector 405 forms a radiation beam B. Radiation beam B is focused at a point (e.g., intermediate focus 406) to form an image of plasma formation region 404, which acts as a virtual radiation source for irradiating system IL. The point where radiation beam B is focused may be referred to as the intermediate focus (IF) (e.g., intermediate focus 406). Radiation source SO is configured such that intermediate focus 406 is located at or near an opening 408 in the enclosure structure 409 of radiation source SO.

[0086] A radiation beam B is transmitted from a radiation source SO to an illumination system IL, which is configured to adjust the radiation beam B. The radiation beam B is transmitted from the illumination system IL and incident on a patterned device MA held by a support structure MT. The patterned device MA reflects and patterns the radiation beam B. After reflection from the patterned device MA, the patterned radiation beam B enters a projection system PS. The projection system includes a plurality of mirrors configured to project the radiation beam B onto a substrate W held by a substrate stage WT. The projection system PS may apply a reduction factor to the radiation beam to form an image with features smaller than the corresponding features on the patterned device MA. For example, a reduction factor of four may be applied. Although the projection system PS is shown in FIG. 2 as having two mirrors, the projection system may include any number of mirrors (e.g., six mirrors).

[0087] The radiation source SO may also include components not shown in Figure 4. For example, a spectral filter may be provided in the radiation source SO. The spectral filter may substantially transmit EUV radiation, but substantially block radiation of other wavelengths, such as infrared radiation.

[0088] The radiation source SO (or radiation system) may further include a fuel target imaging system to obtain an image of the fuel target (e.g., droplets) in the plasma forming region 404, or more specifically, to obtain an image of the shadow of the fuel target. The fuel target imaging system can detect light diffracted from the edge of the fuel target. The reference to an image of a fuel target below should also be understood as an image of the shadow of the fuel target or a diffraction pattern caused by the fuel target.

[0089] The fuel target imaging system may include a photodetector such as a CCD array or a CMOS sensor, but it should be understood that any imaging device suitable for acquiring an image of the fuel target may be used. It should be understood that, in addition to a photodetector, the fuel target imaging system may include optical components such as one or more lenses. For example, the fuel target imaging system may include a camera 410, such as a photodetector or a combination of a photodetector and one or more lenses. Optical components may be selected such that the photodetector or camera 410 acquires near-field and / or far-field images. The camera 410 may be positioned at any suitable location within the radiation source SO, from which the camera has a line of sight to the plasma forming region 404 and one or more markers (not shown in FIG. 4) disposed on the radiation collector 405. However, in some cases, it may be necessary to position the camera 410 away from the propagation path of one or more laser beams 402 and away from the trajectory of the fuel target emitted from the fuel target generator 403 to avoid damage to the camera 410. Depending on the configuration, camera 410 is configured to provide an image of the fuel target to controller 411 via connector 412. Connector 412 is shown as a wired connection, but it should be understood that connector 412 (and other connectors mentioned herein) may be implemented as wired or wireless connections or a combination thereof.

[0090] As shown in FIG. 4, the radiation source SO may include a fuel target generator 403 configured to generate fuel targets 403' (e.g., discrete tin droplets) and emit the fuel targets 403' toward the plasma formation region 404. The radiation source SO may further include a laser system 401 configured to impact one or more of the fuel targets 403' with one or more laser beams 402 to generate plasma 407 at the plasma formation region 404. The radiation source SO may further include a radiation collector 405 (e.g., a radiation collector CO) configured to collect radiation emitted by the plasma 407.

[0091] Example: Cooling equipment for magnified photomasks

[0092] Figures 5 through 10 illustrate an example reduction mask cooling device for removing heat from a patterning device MA (e.g., a mask, reduction mask, or dynamic patterning device) positioned between the illumination system IL and the projection system PS in the example lithography apparatus 100 or 100'. In some embodiments, the example reduction mask cooling device described with reference to Figures 5 through 10 may be included in or associated with an example lithography apparatus such as a scanning lithography apparatus.

[0093] Figures 5A and 5B are schematic illustrations of portions of an example lithography apparatus 500 according to some embodiments of the present invention. As shown in Figure 5A, the example lithography apparatus 500 may include an optical system (not depicted) configured to guide a radiation beam 502 (e.g., an EUV radiation beam) onto a magnifying mask 504 (e.g., including a plurality of fluid cooling channels 508 and a plurality of nodules 510) supported by a magnifying mask stage 506 to form a patterned radiation beam. The radiation beam 502 may cause heating of the exposed area 512 of the magnifying mask 504.

[0094] In some embodiments, the lithography apparatus 500 may include a photomask cooling device 520 configured to remove heat from the photomask 504. For example, the photomask cooling device 520 may be configured to remove heat from a first cooling region 514 located adjacent to the exposed area 512 of the photomask 504 (e.g., in the negative Y direction). Alternatively, the photomask cooling device 520 may be configured to remove heat from a second cooling region 516 located adjacent to the exposed area 512 of the photomask 504 (e.g., in the positive Y direction).

[0095] In some embodiments, the first cooling region 514, the second cooling region 516, or both may be located within approximately 3 cm or less of the line bisecting the exposed region 512. In some embodiments, the first cooling region 514, the second cooling region 516, or both may be located within approximately 2 cm or less of the edge of the exposed region 512. In some embodiments, the photomask cooling device 520 may include a cooling element configured to be positioned below the photomask 504 and adjacent to the exposed region 512. In some embodiments, the cooling element may be in thermal communication with the photomask 504. In some embodiments, the cooling element may be separated from the exposed region 512 in a direction corresponding to the scanning direction of the lithography apparatus 500. In some embodiments, the distance d between the upper surface of the cooling element (e.g., the first top 536, the second top 546) and the lower surface of the photomask 504 may be less than approximately 1 mm. In some cases, the distance d can be between approximately 50 micrometers and approximately 100 micrometers.

[0096] In some embodiments, the cooling element may include a body having a chamber connected to a channel configured to deliver gas to a chamber. In some embodiments, the top of the chamber may be configured to be positioned adjacent to the magnifying glass 504 and may include an assembly of openings (e.g., one or more openings) configured to output gas toward the magnifying glass 504. In some embodiments, the assembly of openings includes a row of apertures or an array of apertures. In some embodiments, the body of the cooling element may further include at least one movable optical valve configured to selectively close at least a subset of the row of apertures or the array of apertures. In other embodiments, the cooling element may include an open cavity provided in the uppermost surface of the body relative to the magnifying glass 504. In some embodiments, the body may be flexible to control cooling provided by a portion of the gas disposed (e.g., present) between the cooling element and the magnifying glass 504. In some embodiments, the photomask cooling device 520 may further include a heat shield positioned between a portion of the cooling element and the photomask 504. In some embodiments, the heat shield may be configured to reduce the amount of heat removed from the photomask 504 by a portion of the cooling element.

[0097] In some embodiments, the photomask cooling device 520 may include a pair of cooling elements, the pair of cooling elements including a first cooling element 530 and a second cooling element 540. In some embodiments, the pair of cooling elements may be provided on opposite sides of the exposure area 512. For example, the first cooling element 530 may be disposed below the photomask 504 and adjacent to the exposure area 512 in the negative Y direction, and the second cooling element 540 may be disposed below the photomask 504 and adjacent to the exposure area 512 in the positive Y direction.

[0098] As shown in FIG. 5B, in some embodiments, the first cooling element 530 may include a first body 532, the first body including a first chamber 534 connected to a first channel (not depicted) configured to deliver a first gas (e.g., H2) to a first chamber 534. In some embodiments, a first top 536 of the first chamber 534 may be positioned adjacent to the magnifying glass 504 (e.g., at a distance d below the magnifying glass 504 in the negative Z direction). In some embodiments, the first top 536 may include a first set of openings 538 defined by the first top 536 and configured to output the first gas toward the magnifying glass 504 (e.g., toward a first cooling region 514 as indicated by the first gas flow 539). In some embodiments, the density of the first set of openings 538 may vary (e.g., along a direction transverse to the scanning direction of the scanning lithography apparatus) such that the density of the first set of openings 538 is higher at the outer ends of the first top 536 than in the central portion of the first top 536. In some embodiments, the first body 532 may further include a first fluid cooling channel 533 configured to remove heat from the first body 532. In some embodiments, the photomask cooling device 520 may further include a first heat shield 550 positioned between a portion of the first cooling element 530 and the photomask 504. In some embodiments, the first heat shield 550 may be configured to reduce the amount of heat removed from the photomask 504 by a portion of the first cooling element 530.

[0099] In some embodiments, the second cooling element 540 may include a second body 542 comprising a second chamber 544 connected to a second channel (not depicted) configured to deliver a second gas (e.g., H2) to a second chamber 544. In some embodiments, a second top 546 of the second chamber 544 may be disposed adjacent to the magnifying glass 504 (e.g., at a distance d below the magnifying glass 504 in the negative Z direction). In some embodiments, the second top 546 may include a second set of openings 548 configured to output the second gas toward the magnifying glass 504 (e.g., toward a second cooling region 516 as indicated by the second gas flow 549). In some embodiments, the density of the second set of openings 548 may vary (e.g., along a direction transverse to the scanning direction of the scanning lithography apparatus) such that the density of the second set of openings 548 is higher at the outer ends of the second top 546 than in the central portion of the second top 546. In some embodiments, the second body 542 may further include a second fluid cooling channel 543 configured to remove heat from the second body 542. In some embodiments, the photomask cooling device 520 may further include a second heat shield 560 positioned between a portion of the second cooling element 540 and the photomask 504. In some embodiments, the second heat shield 560 may be configured to reduce the amount of heat removed from the photomask 504 by a portion of the second cooling element 540.

[0100] In some embodiments, the lithography apparatus 500 may be a scanning lithography apparatus configured to form a curved exposure area, and the pair of cooling elements may be flexible. For example, the first cooling element 530 may include a recessed front edge corresponding to the curved exposure area. In another embodiment, the first cooling element 530 may include a protruding front edge corresponding to a reflection of the curved exposure area (e.g., around an axis extending transversely to the scanning direction of the scanning lithography apparatus). In yet another embodiment, the first cooling element 530 may include a top member that is curved (e.g., transversely to the scanning direction of the scanning lithography apparatus) such that the outer end of the top member is closer to the magnification mask 504 than the central portion of the top member.

[0101] FIG6 is a schematic illustration of a portion of an example lithography apparatus 600 according to some embodiments of the present invention. As shown in FIG6, the example lithography apparatus may include an optical system (not depicted) configured to guide a radiation beam 602 (e.g., an EUV radiation beam) onto a magnifying mask 604 supported by a magnifying mask stage 606 to form a patterned radiation beam. The radiation beam 602 may cause heating of the exposed area 612 of the magnifying mask 604.

[0102] In some embodiments, the lithography apparatus 600 may include a photomask cooling device 620 configured to remove heat from the photomask 604 (e.g., from a first cooling region 614 and a second cooling region 616 disposed adjacent to the exposure area 612). In some embodiments, the photomask cooling device 620 may include a first cooling element 630 and a second cooling element 640 disposed below the photomask 604 (e.g., within a vertical distance d of less than about 1 mm below the photomask 604 in the negative Z direction) and adjacent to the exposure area 612 (e.g., within a distance of less than about 3 cm). In some embodiments, the first cooling element 630 may include a first body 632 including a first chamber 634 connected to a gas source 680 (e.g., an H2 source having an H2 valve), the gas source being configured to deliver a first gas (e.g., H2) to the first chamber 634. In some embodiments, the first body 632 may further include a first fluid cooling channel 633 connected to a cooling chamber 682 (e.g., a fluid cooling chamber having vacuum insulation tubes, a heat exchanger, and a cryogenic cooler) and configured to remove heat from the first body 632. In some embodiments, the second cooling element 640 may include a second body 642, which includes a second chamber 644 connected to a gas source 680 configured to deliver a second gas (e.g., H2) to a second chamber 644. In some embodiments, the second body 642 may further include a second fluid cooling channel 643 connected to the cooling chamber 682 and configured to remove heat from the second body 642.

[0103] In some embodiments, the lithography apparatus 600 may further include actuators (e.g., three actuators arranged in a triangle in the XY plane) configured to modify the distance d between the top of the photomask cooling device 620 (e.g., the top of the first cooling element 630 and the top of the second cooling element 640) and the lower surface of the photomask 604. In some embodiments, the actuators may include a first actuator 686A mechanically coupled to the first cooling element 630, a second actuator 686B mechanically coupled to the second cooling element 640, and a third actuator (not depicted) mechanically coupled to both the first cooling element 630 and the second cooling element 640.

[0104] In some embodiments, the lithography apparatus 600 may further include a cooling controller 684 configured to generate a cooling control signal based on timing data for the projection of the patterned radiation beam, absorption data for the exposed area 612 on the magnifying mask 604, and a target heat transfer rate. In some embodiments, the cooling control signal may be configured to instruct the magnifying mask cooling device 620 to actuate an actuator to modify the distance d between the top of the magnifying mask cooling device 620 and the lower surface of the magnifying mask 604. In some embodiments, the distance d between the top of the magnifying mask cooling device 620 and the lower surface of the magnifying mask 604 may be between approximately 50 micrometers and approximately 100 micrometers.

[0105] In some embodiments, the photomask cooling device 620 may further include a first valve (not depicted) configured to selectively restrict a first flow of a first gas within a first chamber 634 of the first cooling element 630. In some embodiments, the first valve may define a first gas delivery channel between a first fluid inlet and a first fluid overflow outlet connected to the first chamber 634. In some embodiments, the first valve may include a first housing portion and a first sliding member. In some embodiments, the first sliding member is slidable between a first position where the first gas delivery channel is unrestricted and a second position where the first gas delivery channel is partially restricted. In some embodiments, the first sliding member may be configured not to physically contact the first housing portion.

[0106] In some embodiments, the reduction mask cooling device 620 may further include a second valve (not depicted) configured to selectively restrict a second flow of a second gas within the second chamber 644 of the second cooling element 640. In some embodiments, the second valve may define a second gas delivery channel between a second fluid inlet and a second fluid overflow outlet connected to the second chamber 644. In some embodiments, the second valve may include a second housing portion and a second sliding member. In some embodiments, the second sliding member is slidable between a second position where the second gas delivery channel is unrestricted and a second position where the second gas delivery channel is partially restricted. In some embodiments, the second sliding member may be configured not to physically contact the second housing portion.

[0107] In some embodiments, the lithography apparatus 600 may further include a photomask temperature adjustment system 688 configured to adjust a first temperature of the photomask 604 to a second temperature higher than the first temperature before the photomask 604 is placed on the photomask stage 606. In some embodiments, the lithography apparatus 600 may further include a heating device (not depicted) configured to heat the photomask 604. In some embodiments, the heating device may include a pair of heating elements, including a first heating element and a second heating element. In some embodiments, the pair of heating elements may be configured to heat a photomask region positioned at opposite ends of the exposure area 612 in a non-scanning direction of the lithography apparatus. In some embodiments, the lithography apparatus 600 may further include a remote temperature sensing system (not depicted) including a photodetector configured to detect thermal radiation emitted from a target area of ​​the photomask 604.

[0108] In some embodiments, the cooling control signal generated by the cooling controller 684 may be further configured to modify the operation of the photomask cooling device 620 (e.g., the first cooling element 630, the second cooling element 640), the gas source 680, the cooling chamber 682, the actuators (e.g., the first actuator 686A, the second actuator 686B), the photomask temperature adjustment system 688, any other suitable components or devices, or any combination thereof. In some embodiments, the cooling controller 684 may be configured to transmit the cooling control signal (e.g., directly or indirectly via one or more wired or wireless communication paths) to the photomask cooling device 620 (e.g., the first cooling element 630, the second cooling element 640), the gas source 680, the cooling chamber 682, the actuators (e.g., the first actuator 686A, the second actuator 686B), the photomask temperature adjustment system 688, any other suitable components or devices, or any combination thereof.

[0109] Figures 7A and 7B are schematic illustrations of a portion of an example lithography apparatus 700A in a first time and a portion of an example lithography apparatus 700B in a second time after the first time, according to some embodiments of the present invention. As shown in Figure 7A, the example lithography apparatus 700A may include an optical system (not depicted) configured to guide a radiation beam 702 (e.g., an EUV radiation beam) onto a magnifying mask 704 supported by a magnifying mask stage (not depicted) to form a patterned radiation beam by reflecting the radiation beam 702 away from patterned areas of the magnifying mask 704, such as patterned areas 705A, 705B, and 705C. The radiation beam 702 may cause heating of the exposed areas of the magnifying mask 704.

[0110] In some embodiments, the lithography apparatus 700A may include a photomask cooling device 720 configured to remove heat from the photomask 704. For example, the photomask cooling device 720 may be configured to remove heat from a first cooling region disposed adjacent to the exposed area of ​​the photomask 704 (e.g., in the negative Y direction). Alternatively, the photomask cooling device 720 may be configured to remove heat from a second cooling region disposed adjacent to the exposed area of ​​the photomask 704 (e.g., in the positive Y direction).

[0111] In some embodiments, the photomask cooling device 720 may include a first cooling element 730 and a second cooling element 740 positioned on opposite sides of the exposed area. For example, the first cooling element 730 may be disposed below the photomask 704 and adjacent to the exposed area in the negative Y direction, and the second cooling element 740 may be disposed below the photomask 704 and adjacent to the exposed area in the positive Y direction.

[0112] In some embodiments, the first cooling element 730 may include a first body 732, the first body including a first chamber 734 connected to a first channel (not depicted) configured to deliver a first gas (e.g., H2) to a first chamber 734. In some embodiments, at a first time, a first top 736 of the first chamber 734 may be positioned adjacent to the magnifying mask 704 in the negative Z direction at approximately a first distance d1 below the magnifying mask 704. In some embodiments, the first top 736 may include a first set of openings 738 configured to output the first gas toward a first cooling region of the magnifying mask 704, as indicated by a first gas flow 739. In some embodiments, the density of the first set of openings 738 may vary in a direction transverse to the scanning direction 701, such that the density of the first set of openings 738 is higher at the outer ends of the first top 736 than in the central portion of the first top 736. In some embodiments, the first body 732 may further include a first fluid cooling channel 733 configured to remove heat from the first body 732. In some embodiments, the photomask cooling device 720 may further include a first heat shield 750 positioned between a portion of the first cooling element 730 and the photomask 704. In some embodiments, the first heat shield 750 may be configured to reduce the amount of heat removed from the photomask 704 by a portion of the first cooling element 730.

[0113] In some embodiments, the second cooling element 740 may include a second body 742, which includes a second chamber 744 connected to a second channel (not depicted) configured to deliver a second gas (e.g., H2) to a second chamber 744. In some embodiments, a second top 746 of the second chamber 744 may be positioned adjacent to the magnifying mask 704 in the negative Z direction at approximately a first distance d1 below the magnifying mask 704. In some embodiments, the second top 746 may include a second set of openings 748 configured to output the second gas toward a second cooling region of the magnifying mask 704, as indicated by a second gas flow 749. In some embodiments, the density of the second set of openings 748 may vary along a direction transverse to the scanning direction 701, such that the density of the second set of openings 748 is higher at the outer ends of the second top 746 than in the central portion of the second top 746. In some embodiments, the second body 742 may further include a second fluid cooling channel 743 configured to remove heat from the second body 742. In some embodiments, the photomask cooling device 720 may further include a second heat shield 760 positioned between a portion of the second cooling element 740 and the photomask 704. In some embodiments, the second heat shield 760 may be configured to reduce the amount of heat removed from the photomask 704 by a portion of the second cooling element 740.

[0114] Referring to FIG7B, in some embodiments, the photomask cooling device 720 may include or be mechanically coupled to actuators (e.g., three actuators arranged in a triangle in the XY plane), which are configured to modify the distance between the lower surface of the photomask 704 and the first top 736 of the first cooling element 730, the second top 746 of the second cooling element 740, or both, in response to a cooling control signal received by the self-cooling controller.

[0115] In some embodiments, the photomask cooling device 720 may include, or be electrically or otherwise communicatively coupled to, a cooling controller configured to generate a cooling control signal based on timing data for the projection of the patterned radiation beam, absorption data for the exposed area on the photomask 704, and a target heat transfer rate. In some embodiments, the cooling control signal may be configured to instruct the photomask cooling device 720 to actuate the actuators to modify (e.g., by means of a change in distance Δd) the distance between the lower surface of the photomask 704 and the first top 736 of the first cooling element 730, the second top 746 of the second cooling element 740, or both. In some configurations, the change in distance Δd = |d1 - d2|, where a positive value of Δd corresponds to a movement of the photomask cooling device 720 in the positive Z direction, thus increasing the effective heat transfer rate to achieve increased cooling, and a negative value of Δd corresponds to a movement of the photomask cooling device 720 in the negative Z direction, thus decreasing the effective heat transfer rate to achieve reduced cooling. In some configurations, the cooling controller may be configured to transmit cooling control signals (e.g., directly or indirectly via one or more wired or wireless communication paths) to the photomask cooling device 720 (e.g., the first cooling element 730, the second cooling element 740), actuators, any other suitable components or devices, or any combination thereof.

[0116] In an illustrative and non-limiting example, as shown in FIG7A, when the exposed area of ​​the magnifying mask 704 conforms to the patterned area 705B, the first distance d1 may be approximately 70 micrometers at the first time, thereby causing relatively less heating of the magnifying mask 704. Subsequently, the cooling controller may determine that the gap in the patterned area (e.g., causing relatively more heating of the magnifying mask 704) appears at a second time later than the first time, and in response to the determination, generate a cooling control signal, which is configured to instruct the magnifying mask cooling device 720 to actuate the actuator to modify the distance between the lower surface of the magnifying mask 704 and the first top 736 of the first cooling element 730, the second top 746 of the second cooling element 740, or both, by changing the distance Δd by approximately 20 micrometers to increase the effective heat transfer rate to achieve increased cooling in the first and second cooling areas adjacent to the exposed area of ​​the magnifying mask 704. The cooling controller can transmit a cooling control signal to the actuator (e.g., directly or indirectly via the photomask cooling device 720). The actuator can receive the cooling control signal and modify (e.g., by moving the photomask cooling device upwards as indicated by arrow 742) the distance between the lower surface of the photomask 704 and the first top 736 of the first cooling element 730, the second top 746 of the second cooling element 740, or both, by changing Δd by a distance of approximately 20 micrometers, such that when the exposed area of ​​the photomask 704 does not conform to the patterned area, the second distance d2 is approximately 50 micrometers at a second time, as shown in FIG7B.

[0117] Figures 8, 9, and 10 schematically depict example embodiments of a reduction-size mask cooling device configured according to various configurations to solve the problem of uniform cooling power distribution. The embodiments of Figures 8, 9, and 10 may include some features common to the previously described embodiments, such as features from the embodiments described with reference to Figures 5A, 5B, 6, 7A, and 7B. For brevity, features depicted and / or described in conjunction with other embodiments are omitted below.

[0118] In one embodiment, FIG8 depicts a cross-section 800 of a portion (e.g., viewed from below) of a magnifying mask cooling apparatus 40 including a first cooling element 4002 and a second cooling element 4003. A curved exposure region E is also depicted. The first cooling element 4002 and the second cooling element 4003 are curved in the curved exposure region E. The first cooling element 4002 may be separable into three chambers: an inner chamber 4004; a first outer chamber 4005; and a second outer chamber 4006. The first outer chamber 4005 and the second outer chamber 4006 are located on either side of the inner chamber 4004. Following the Cartesian coordinate system for lithography equipment, the first outer chamber 4005 and the second outer chamber 4006 are located on either side of the inner chamber 4004 in the X direction (e.g., on either side of the inner chamber in the non-scanning direction). The second cooling element 4003 may have a single chamber 4008. The top, which has an opening (not depicted), can be positioned above chambers 4004, 4005, 4006 and 4008, and cooling gas can flow out from the opening to the magnifying glass to cool the magnifying glass.

[0119] In some configurations, the first cooling element 4002 and the second cooling element 4003 may have a curved shape having a curve that substantially corresponds to the curve of the curved exposed region E. The width of the first cooling element 4002 and the second cooling element 4003 may be different from the width of the curved exposed region E (for example, the curved exposed region E may be narrower than the cooling element).

[0120] In some configurations, the first cooling element 4002 may be considered to have a recessed leading edge. This leading edge may be the edge at which the first cooling element 4002 first encounters the target region 4000 in the scanning direction as it is directed toward the second cooling element 4003 (e.g., during a scan exposure in the negative Y direction, as indicated by the arrow shown in FIG8, the first cooling element 4002 encounters the target region 4000 before the second cooling element 4003).

[0121] In some configurations, the second cooling element 4003 may be considered to have a protruding leading edge. The leading edge may be the edge of the target area that the second cooling element 4003 first encounters when it is guided to the first cooling element 4002 in the scanning direction (e.g., during a scan exposure in the positive Y direction, opposite to the arrow shown in FIG8, the second cooling element 4003 encounters the target area before the first cooling element 4002).

[0122] In some cases, during scanning exposure using a magnifying mask moving in the negative Y direction, the outer edge 4001 of the target area 4000 is heated by a radiation beam before the middle portion of the curved exposure area E. This can cause deformation of the curved exposure area E, which may be difficult to correct using the projection system PS of the lithography apparatus 100 or 100'. This can be addressed by providing cooling gas in the first outer chamber 4005 and the second outer chamber 4006 before providing cooling gas to the inner chamber 4004. This can be achieved, for example, by opening the valves connected to the first outer chamber 4005 and the second outer chamber 4006 before opening the valve connected to the inner chamber 4004. Alternatively, stronger cooling can be provided from the first outer chamber 4005 and the second outer chamber 4006 than from the inner chamber 4004. For example, stronger cooling can be achieved by providing cooling gas at a higher pressure or lower temperature in the first outer chamber 4005 and the second outer chamber 4006 than in the inner chamber 4004.

[0123] In some embodiments, the photomask cooling device 40 can provide concentrated or dedicated cooling at the outer edge 4001 of the target region 4000. As a result, when exposure of the target region 4000 begins, the outer edge 4001 of the target region 4000 can be cooled as much as the central portion of the target region 4000. Therefore, the initial heating of the outer edge 4001 of the target region 4000 during lithography exposure causes a third-order deformation reduction in the curved exposure region E.

[0124] In some embodiments, the second cooling element 4003 may consist of a single chamber 4008 instead of three chambers. This is because third-order deformation can be reduced when the scan direction is reversed (e.g., during scan exposure in the positive Y direction, opposite to the arrow shown in FIG8) and the second cooling element 4003 is located in the target region 4000 before the curved exposure region E. In some embodiments, third-order deformation may occur when the outer edge 4001 of the target region 4000 is heated before the central portion of the target region 4000 during scan exposure in the negative Y direction, but this may not occur during scan exposure in the positive Y direction. Because the third-order deformation problem may not occur when the second cooling element 4003 is before the curved exposure region E, dividing the single chamber 4008 into three chambers may not provide much benefit. As a result, the reduction mask cooling device 40 can use the first cooling element 4002 and the second cooling element 4003 to reduce the third-order deformation of the target region 4000. The first cooling element 4002 and the second cooling element 4003 can have a relatively simple structure (e.g., in an embodiment where having three chambers provides the benefit, there are three chambers 4004, 4005, and 4006 on one side; but in an embodiment where having three chambers does not provide much benefit, there is only one chamber 4008 on the other side). In some cases, the second cooling element 4003 can be separated into three chambers, similar to the first cooling element 4002.

[0125] In some samples, due to the curved shape of the exposed slit, the center, left, and right sides of the curved exposure area E are exposed earlier depending on the scanning direction. To minimize overlay error, it is preferable to cool the width of the curved exposure area E in different ways. A curved cooling gas flux configured across the width of the cooling surface to obtain a cooling flux distribution can be achieved by selecting an appropriate distribution of the holes in the top of the cooling element. However, a cooling flux distribution across the width works best in a rarefied (e.g., low-pressure) gas operating state rather than a continuous (e.g., high-pressure) gas operating state. In such samples, a gas (e.g., H2) can be selected to work in a rarefied operating state, and another gas (e.g., N2) can be selected to work in a state close to continuous operation. If a blocked airflow is selected, the profile can scale almost linearly with the gap height.

[0126] FIG9 depicts a cross-section 900 of a portion (e.g., viewed from below) of a portion of a photomask cooling device 41 including a first cooling element 4022 and a second cooling element 4023. The first cooling element 4022 includes a first chamber 4024, and the second cooling element 4023 includes a second chamber 4025. A curved exposure area E is also depicted in FIG9. A top having an opening (not depicted) may be positioned above the first chamber 4024 and the second chamber 4025, and cooling gas may flow from the opening onto the photomask to cool the photomask.

[0127] In some configurations, the curved exposed region E, the first chamber 4024, and the second chamber 4025 are all curved. However, in the embodiment shown in FIG9, the first chamber 4024 of the first cooling element 4022 has a curve that is substantially a mirror image (e.g., a reflection around the X-axis) of the curved exposed region E. In other words, the first chamber 4024 of the first cooling element 4022 may be curved in the opposite direction to the curved exposed region E. The curve of the second chamber 4025 of the second cooling element 4023 substantially corresponds to the curve of the curved exposed region E.

[0128] In some configurations, during scanning exposure in the negative Y direction, as depicted by the arrows in FIG9, the first cooling element 4022 is located in the region of the magnifying mask before the curved exposure region E. In some configurations, it may be necessary to provide more cooling to the curved exposure region E at its edge than at its center. In the embodiment shown in FIG9, this can be achieved by delaying the time at which cooling is provided by the first cooling element 4022. Specifically, cooling can be delayed (e.g., based on a cooling control signal or a portion thereof) so that it does not begin when the center point 4026 of the leading edge of the first chamber 4024 passes the starting point of the target region 4000. Instead, cooling can be delayed, for example, until the outer end 4028 of the first chamber 4024 reaches the outer edge 4001 of the target region 4000. When using this approach, the outer edge 4001 of the target region 4000 receives full cooling from the first cooling element 4022, while the central portion of the target region 4000 may not receive full cooling but instead receives less cooling. Therefore, third-order deformation caused by the outer edge 4001 of the target region 4000 exposed before the central region of the target region 4000 can be prevented or reduced.

[0129] In some samples, the third-order deformation problem may not occur when scanning in the opposite direction (e.g., in the positive Y direction). For this reason, the second chamber 4025 of the second cooling element 4023 may not be a mirror image of the curved exposed area E.

[0130] FIG10 depicts a cross-section 1000 of a portion (e.g., viewed from one side) of a reticle cooling device 42 including a cooling element 4040 according to a given configuration. In FIG10, the reticle cooling device 42 is depicted using a cross-section along the Y direction. The cooling element 4040 includes a housing 4044 that defines a chamber 4041 and a top member 4042 (e.g., which may also be referred to as a curved top). The top member 4042 may have openings (not depicted) through which cooling gas is transferred from the chamber 4041 to the reticle R during use. The top member 4042 may be curved such that the outer end of the top member 4042 (e.g., in the X direction) is closer to the reticle R than the central portion of the top member 4042. This advantageously provides stronger cooling of the reticle at the edge of the exposure area E (e.g., the curved exposure area E shown in FIG8 and FIG9) than at the center of the exposure area E. This can reduce the third-order deformation. The curvature of the top component 4042 can be, for example, substantially parabolic.

[0131] In some configurations, a piezoelectric actuator (not depicted) may be provided at the end of the top member 4042. The piezoelectric actuator may be used to modify (e.g., based on a cooling control signal or a portion thereof) the curvature of the top member 4042. For example, the piezoelectric actuator may be used to move the top member from a curved configuration (e.g., as depicted in FIG10) to a flat configuration. For example, a curved configuration may be used when the edge of the target area is irradiated by the exposed area E but the central portion of the target area is not irradiated. When the entire target area is irradiated by the exposed area E, the top member 4042 may then move to a flat profile.

[0132] In other configurations (not depicted), instead of providing a top component 4042, the top of the housing 4044 may be flat, but may have a higher density of openings at the outer ends of the top (e.g., in the X direction) than in the central portion of the top. The pore density can be configured to provide cooling equivalent to that provided by a parabolic curved top having a constant pore density. The term "pore density" refers to the proportion of an open top compared to a closed top proportion.

[0133] In some embodiments, the first cooling element and the second cooling element located on either side of the exposed area E can be independently switched on and off. This can be applied to any of the embodiments depicted in Figures 8, 9 and 10, or in combination with other embodiments.

[0134] In some configurations, the features described with reference to Figures 8, 9, and 10 can be combined with each other or with other features. For example, the inverted curvature depicted in Figure 9 can be separated from the cooling chamber to form an internal chamber and an external chamber combination as depicted in Figure 8. In another example, the inverted curvature depicted in Figure 9 can be combined with the independent switching of a first cooling element and a second cooling element. In another example, a curved top (or modified pore density) can be combined with the independent switching of a first cooling element and a second cooling element.

[0135] In some embodiments, any or a combination of the photomask cooling devices disclosed herein may form part of a photomask inspection device. The photomask inspection device may use EUV radiation to irradiate the photomask and use an imaging sensor to monitor the radiation reflected from the photomask. The image received by the imaging sensor is used to determine whether a defect exists in the photomask. The photomask inspection device may include optics (e.g., a mirror) configured to receive EUV radiation from an EUV radiation source and form it into a radiation beam to be guided at the photomask. The photomask inspection device may further include optics (e.g., a mirror) configured to collect EUV radiation reflected from the photomask and form an image of the photomask at the imaging sensor. The photomask inspection device may include a processor configured to analyze the image of the photomask at the imaging sensor and determine from the analysis whether any defects exist on the photomask. The processor can be further configured to determine whether the detected reduction mask defects will result in unacceptable defects in the image projected onto the substrate when the reduction mask is used by the lithography equipment.

[0136] In some embodiments, any or a combination of the photomask cooling devices disclosed herein may form part of a measuring device. The measuring device may be used to measure the alignment of a projected pattern formed on a substrate with respect to a pattern already present on the substrate. This measurement of relative alignment may be referred to as overlay. The measuring device may be positioned, for example, adjacent to a lithography apparatus, and may be used to measure overlay before the substrate (and resist) have been treated.

[0137] In some embodiments, although the disclosed embodiments are described in the context of lithography equipment, the embodiments disclosed herein can also be used in the context of other equipment. For example, the embodiments disclosed herein may form part of any equipment for measuring or processing objects such as substrates (e.g., wafers) or lithography masks (e.g., masks or other patterning devices). Such equipment may generally be referred to as lithography tools. Such lithography tools may use vacuum conditions (e.g., such as in EUV radiation) or ambient (non-vacuum) conditions (e.g., such as in DUV radiation). In some embodiments, the term "EUV radiation" may be considered to encompass electromagnetic radiation having wavelengths in the range of 4 to 20 nanometers (e.g., in the range of 13 to 14 nanometers). EUV radiation may have wavelengths less than 10 nanometers (e.g., in the range of 4 to 10 nanometers, such as 6.7 nanometers or 6.8 nanometers).

[0138] Example program for heat removal from self-expanding photomasks

[0139] FIG11 is an example method 1100 for removing heat from a self-reducing photomask according to some aspects or a portion thereof of the present invention. The operation described with reference to example method 1100 may be performed by or in accordance with any of the systems, devices, components, technologies or combinations thereof described herein, such as those described with reference to FIG1 to 10 above and FIG12 below.

[0140] At operation 1102, the method may include generating a cooling control signal by means of a cooling controller based on timing data for the projection of a patterned radiation beam (the patterned radiation beam being formed by irradiating an exposed area on a magnifying mask supported by a magnifying mask stage), absorption data for the exposed area, and a target heat transfer rate. In some embodiments, the cooling control signal may instruct the magnifying mask cooling device to actuate an actuator to modify the distance between the magnifying mask and the top of a chamber connected to a channel for delivering gas to the chamber. In some embodiments, the channel may be disposed within the body of a cooling element of the magnifying mask cooling device. In some embodiments, in addition to or as an alternative to operation 1102, the method may also include measuring the distortion of the magnifying mask using two references (e.g., transmission image sensor (TIS) markers or any other suitable references) and using the distortion measurement to adjust the cooling, heating, or both provided by the magnifying mask cooling device. In some configurations, the generation of the cooling control signal may be achieved using suitable mechanical, electrical or other methods, and may include generating the cooling control signal according to any configuration or combination thereof described with reference to Figures 1 to 10 above and Figure 12 below.

[0141] At operation 1104, the method may include transmitting a cooling control signal to an actuator via a cooling controller. In some embodiments, the transmission of the cooling control signal may be implemented using suitable mechanical, electrical or other methods, and includes transmitting the cooling control signal according to any embodiment or combination of embodiments described with reference to Figures 1 to 10 above and Figure 12 below.

[0142] At operation 1106, the method may include modifying the distance between the magnifying mask and the top (e.g., from a first distance d1 shown in FIG. 7A to a second distance d2 shown in FIG. 7B) by means of an actuator and based on a cooling control signal to modify the heat transfer rate associated with heat removal from the magnifying mask to a target heat transfer rate. In some embodiments, the modification of the distance between the magnifying mask and the top may be implemented using suitable mechanical, electrical or other methods, and includes modifying the distance between the magnifying mask and the top according to any embodiment or combination of embodiments described with reference to FIG. 1 to FIG. 10 above and FIG. 12 below.

[0143] Instance Computing System

[0144] The present invention may be implemented in hardware, firmware, software, or any combination thereof. The present invention may also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. The machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, the machine-readable medium may include: read-only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagation signals (e.g., carrier waves, infrared signals, digital signals, etc.); and other machine-readable media. Furthermore, firmware, software, conventions, instructions, and combinations thereof may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only, and such actions are actually generated by a computing device, processor, controller, or other device that executes the firmware, software, conventions, instructions, or combinations thereof, thereby enabling actuators or other devices (e.g., servo motors, robotic devices) to interact with the physical world.

[0145] Various configurations may be implemented using one or more computing systems, such as the instance computing system 1200 shown in FIG. 12. The instance computing system 1200 may be a specific computer capable of performing the functions described herein, such as: the instance laser system 401 described with reference to FIG. 4; the photomask cooling device 520 described with reference to FIG. 5; the photomask cooling device 620, gas source 680, cooling box 682, cooling controller 684, actuator (e.g., first actuator 686A, second actuator 686B) or photomask temperature regulation system 688 described with reference to FIG. 6; the photomask cooling device 720, cooling controller or actuator described with reference to FIG. 7; any other suitable system, subsystem or component; or any combination thereof. The instance computing system 1200 may include one or more processors (also referred to as a central processing unit or CPU), such as processor 1204. Processor 1204 is connected to communication infrastructure 1206 (e.g., bus). The instance computing system 1200 may also include user input / output devices 1203, such as monitors, keyboards, and indicators, that communicate with the communication infrastructure 1206 via a user input / output interface 1202. The instance computing system 1200 may also include main memory 1208 (e.g., one or more main storage devices), such as random access memory (RAM). Main memory 1208 may include one or more levels of cache memory. Main memory 1208 has control logic (e.g., computer software) and / or data stored therein.

[0146] The instance computing system 1200 may also include auxiliary memory 1210 (e.g., one or more auxiliary storage devices). For example, auxiliary memory 1210 may include hard disk drive 1212 and / or removable storage drive 1214. Removable storage drive 1214 may be floppy disk drive, tape drive, compact optical drive, optical storage device, tape backup device, and / or any other storage device / drive.

[0147] The removable storage drive 1214 can interact with the removable storage unit 1218. The removable storage unit 1218 includes a computer-usable or readable storage device on which computer software (control logic) and / or data are stored. The removable storage unit 1218 can be a floppy disk, magnetic tape, optical disc, DVD, optical storage disk, and / or any other computer data storage device. The removable storage drive 1214 reads from and / or writes to the removable storage unit 1218.

[0148] According to some embodiments, auxiliary memory 1210 may include other components, tools, or other means for allowing computer programs and / or other instructions and / or data to be accessed by instance computing system 1200. For example, such components, tools, or other means may include removable storage unit 1222 and interface 1220. Examples of removable storage unit 1222 and interface 1220 may include program cartridges and cartridge interfaces (such as program cartridges and cartridge interfaces found in video game devices), removable memory chips (such as EPROM or PROM) and associated sockets, memory sticks and USB ports, memory cards and associated memory card slots, and / or any other removable storage unit and associated interface.

[0149] The instance computing system 1200 may further include a communication interface 1224 (e.g., one or more network interfaces). The communication interface 1224 enables the instance computing system 1200 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (individually and collectively referred to as remote device 1228). For example, the communication interface 1224 may allow the instance computing system 1200 to communicate with the remote device 1228 via a communication path 1226, which may be wired and / or wireless and may include any combination of LAN, WAN, Internet, etc. Control logic, data, or both may be transmitted to and from the instance computing system 1200 via the communication path 1226.

[0150] The operations described in the foregoing embodiments of the present invention can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations in the foregoing embodiments can be performed in hardware, software, or both. In some embodiments, tangible non-transitory devices or articles of manufacture include tangible non-transitory computer-usable or readable media on which control logic (software) is stored, also referred to herein as computer program products or program storage devices. These include, but are not limited to: instance computing system 1200, main memory 1208, secondary memory 1210, and removable storage units 1218 and 1222, and tangible articles embodying any combination of the foregoing. This control logic, when executed by one or more data processing devices (such as instance computing system 1200), causes such data processing devices to operate as described herein.

[0151] Based on the teachings contained herein, it will be apparent to those skilled in the art how to manufacture and use embodiments of the present invention using data processing devices, computer systems, and / or computer architectures other than those shown in FIG12. Specifically, embodiments of the present invention can be implemented and operated using software, hardware, and / or operating systems other than those described herein.

[0152] The embodiments may be further described using the following terms: 1. A lithography apparatus comprising: an optical system configured to guide a radiation beam onto a magnifying mask supported by a magnifying mask stage to form a patterned radiation beam, wherein the radiation beam causes heating of an exposed area of ​​the magnifying mask; and a magnifying mask cooling device configured to remove heat from the magnifying mask, wherein the magnifying mask cooling device comprises: a cooling element disposed below the magnifying mask and adjacent to the exposed area, wherein: the cooling element comprises a body including a chamber connected to a channel configured to deliver gas to a chamber, the top of the chamber being disposed adjacent to the magnifying mask and including an opening configured to output gas toward the magnifying mask; an actuator configured to modify the distance between the top and the magnifying mask; and a cooling controller configured to: A cooling control signal is generated based on timing data for the projection of the patterned radiation beam, absorption data for the exposed area on the photomask, and the target heat transfer rate, wherein the cooling control signal is configured to instruct the photomask cooling device actuator to modify the distance between the top and the photomask; and the cooling control signal is transmitted to the actuators. 2. The lithography apparatus of claim 1, wherein the distance between the top and the photomask is between about 50 micrometers and about 100 micrometers. 3. The lithography apparatus of claim 1, wherein the cooling element is separated from the exposed area in a direction corresponding to the scanning direction of the lithography apparatus. 4. The lithography apparatus of claim 1, wherein: the cooling element is a first cooling element; the photomask cooling device includes a pair of cooling elements, the pair of cooling elements including a first cooling element and a second cooling element; and the pair of cooling elements are provided on opposite sides of the exposed area. 5. The lithography apparatus of item 4, wherein: the lithography apparatus includes a scanning lithography apparatus configured to form a curved exposure area; and the pair of cooling elements are curved. 6. The lithography apparatus of item 5, wherein the first cooling element includes a recessed leading edge corresponding to the curved exposure area. 7. The lithography apparatus of item 5, wherein the first cooling element includes a protruding leading edge corresponding to the reflection of the curved exposure area. 8. The lithography apparatus of item 5, wherein the first cooling element includes a top member that is curved transversely to the scanning direction of the scanning lithography apparatus, such that the outer end of the top member is closer to the magnification mask than the center portion of the top member. 9. The lithography apparatus of clause 5, wherein: the top of the chamber of the body of the cooling element is the first top of the first chamber of the first body of the first cooling element; the openings include a first set of openings defined by the first top; the density of the first set of openings varies along a direction transverse to the scanning direction of the lithography apparatus; and the density of the first set of openings is higher at the outer end of the first top than in the central portion of the first top.10. The lithography apparatus of claim 1, wherein the cooling element further includes an open cavity provided in the uppermost surface of the body relative to the photomask. 11. The lithography apparatus of claim 1, wherein the openings comprise a row of apertures or an array of apertures. 12. The lithography apparatus of claim 11, wherein the body further includes at least one movable optical valve configured to selectively close at least a subset of the row of apertures or the array of apertures. 13. The lithography apparatus of claim 1, further comprising: a heat shield positioned between a portion of the cooling element and the photomask, wherein the heat shield is configured to reduce the amount of heat removed from the photomask by that portion of the cooling element. 14. The lithography apparatus of claim 1, wherein: the channel is a first channel; the photomask cooling apparatus further includes a valve configured to selectively restrict gas flow within the first channel; the valve defines a second channel between a fluid inlet and a fluid outlet connected to the first channel; the valve includes a housing portion and a sliding member; the sliding member is slidable between a first position and a second position, in which the second channel is unrestricted and in the second position the second channel is partially restricted; and the sliding member is configured not to physically contact the housing portion. 15. The lithography apparatus of claim 1, wherein the body is flexible to control cooling provided by a portion of the gas disposed between the cooling element and the photomask. 16. The lithography apparatus of claim 1, further including a photomask temperature adjustment system configured to adjust a first temperature of the photomask to a second temperature higher than the first temperature before the photomask is placed on the photomask stage. 17. The lithography apparatus of claim 1, further comprising: a heating device configured to heat the photomask, wherein: the heating device includes a pair of heating elements, including a first heating element and a second heating element; and the pair of heating elements are configured to heat a photomask region positioned at opposite ends of the exposed area in a non-scanning direction of the lithography apparatus. 18. The lithography apparatus of claim 1, wherein the cooling element is in thermal communication with the photomask.19. A photomask cooling device comprising: a cooling element configured to be disposed below and adjacent to an exposed area of ​​a photomask supported by a photomask stage, wherein: the cooling element includes a body having a chamber connected to a channel configured to deliver gas to a chamber, the top of the chamber being configured to be disposed adjacent to the photomask, and including an opening configured to output gas toward the photomask; actuators configured to modify the distance between the top and the photomask; and a cooling controller configured to: generate a cooling control signal based on timing data of a projection of a patterned radiation beam generated by the photomask, absorption data of the exposed area on the photomask, and a target heat transfer rate, wherein the cooling control signal is configured to instruct the photomask cooling device to actuate the actuators to modify the distance between the top and the photomask; and transmit the cooling control signal to the actuators. 20. A method comprising: generating a cooling control signal by a cooling controller based on timing data for the projection of a patterned radiation beam (the patterned radiation beam being formed by irradiating an exposed area on a photomask supported by a photomask stage), absorption data for the exposed area, and a target heat transfer rate, wherein the cooling control signal instructs a photomask cooling device to actuate actuators to modify the distance between the photomask and the top of a chamber connected to a channel for delivering gas to the chamber, the channel being located within the body of a cooling element of the photomask cooling device; transmitting the cooling control signal from the cooling controller to the actuators; and modifying the distance between the photomask and the top by the actuators based on the cooling control signal to modify a heat transfer rate associated with heat removal from the photomask to the target heat transfer rate.

[0153] Although reference may be specifically made herein to the use of lithography equipment in IC manufacturing, it should be understood that the lithography equipment described herein may have other applications, such as manufacturing integrated optical systems, guiding and detecting patterns for magnetic domain memory, flat panel displays, LCDs, thin-film magnetic heads, etc. Those skilled in the art will understand that, in the context of these alternative applications, any use of the terms "wafer" or "die" herein may be considered synonymous with the more general terms "substrate" or "target portion," respectively. The substrates mentioned herein may be processed before or after exposure in, for example, a coating and developing system unit (a tool for applying a resist layer to a substrate and exposing the resist for development), a measurement unit, and / or a detection unit. Where applicable, the invention herein may be applied to these and other substrate processing tools. Furthermore, the substrate may be processed more than once, for example to produce a multilayer IC, such that the term "substrate" as used herein may also refer to a substrate that already contains multiple processed layers.

[0154] It should be understood that the wording or terminology used herein is for descriptive rather than limiting purposes, and that the terminology or terminology used herein should be interpreted by a person skilled in the art in light of the teachings herein.

[0155] As used herein, the term "substrate" describes a material on which a layer of material has been added. In some cases, the substrate itself may be patterned, and the material added on top of it may also be patterned or left unpatterned.

[0156] The examples disclosed herein are illustrative and not limiting of the embodiments of the invention. Other suitable modifications and adaptations to various conditions and parameters that are commonly encountered in the art and will be obvious to those skilled in the art are within the spirit and scope of the invention.

[0157] Although specific embodiments of the present invention have been described above, it should be understood that such embodiments may be practiced in other ways different from those described. The description is not intended to limit the embodiments of the present invention.

[0158] It should be understood that the Description of Embodiments section, rather than the Prior Art, Summary of the Invention, and Abstract of the Invention sections, is intended to interpret the scope of the patent application. The Summary of the Invention and Abstract of the Invention sections may describe one or more, but not all, exemplary embodiments as contemplated by the inventors, and therefore are not intended to limit the embodiments of the present invention or the scope of the appended patent application in any way.

[0159] Some aspects of the present invention have been described above using function building blocks, which illustrate the implementation of specified functions and their relationships. For ease of description, the boundaries of these function building blocks have been arbitrarily defined herein. Alternative boundaries can be defined as long as the specified functions and their relationships are properly executed.

[0160] The foregoing description of specific embodiments of the present invention will thus fully reveal the general nature of such embodiments: without departing from the general concept of the present invention, others can easily modify and / or adapt such specific embodiments for various applications by applying the knowledge known to those skilled in the art, without conducting improper experiments. Therefore, based on the teachings and instructions presented herein, such adaptations and modifications are intended to be within the meaning and scope of equivalents of the disclosed embodiments.

[0161] The scope and range of the present invention should not be limited by any of the above-described examples or embodiments, but should be defined only by the following claims and their equivalents. [Simplified Explanation of the Diagram]

[0012] The invention is described in accordance with the accompanying drawings, which are incorporated herein by reference and form a part of this specification, and together with the description, are used to explain the principles of the present invention and to enable those skilled in the art to perform and use the present invention.

[0013] FIG1A is a schematic illustration of some examples of reflective lithography devices according to the present invention.

[0014] FIG1B is a schematic illustration of a transmission lithography apparatus of some forms according to the present invention.

[0015] FIG2 is a more detailed schematic illustration of the reflective lithography device shown in FIG1A according to some aspects of the present invention.

[0016] Figure 3 is a schematic illustration of an example lithography unit of some forms according to the present invention.

[0017] Figure 4 is a schematic illustration of an example radiation source for an example reflective lithography device according to some forms of the present invention.

[0018] Figures 5A and 5B are schematic illustrations of examples of a photomask cooling device according to some aspects of the present invention.

[0019] Figure 6 is a schematic illustration of an example cooling system including an example reduction mask cooling device according to some aspects of the present invention.

[0020] Figures 7A and 7B are schematic illustrations of the operation of an example of a photomask cooling device according to some aspects of the present invention.

[0021] Figure 8 is a schematic illustration of another type of condenser cooling device according to some aspects of the present invention.

[0022] Figure 9 is a schematic illustration of another type of condenser cooling device according to some aspects of the present invention.

[0023] Figure 10 is a schematic illustration of another type of condenser cooling device according to some aspects of the present invention.

[0024] Figure 11 is an example method for removing heat from a self-scaling mask according to some of the present invention or a portion thereof.

[0025] Figure 12 is an example computer system for implementing some aspects or parts thereof of the present invention.

[0026] The features and advantages of the present invention will become more apparent from the following detailed description set forth in conjunction with the accompanying drawings, in which similar reference characters always identify corresponding elements. In these drawings, unless otherwise indicated, similar reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Furthermore, typically, the leftmost digit of the reference numeral first appears in the drawing of that reference numeral. Unless otherwise indicated, the drawings provided throughout the present invention should not be interpreted as to-scale drawings.

Claims

1. A lithography apparatus comprising: an optical system configured to guide a radiation beam onto a reticle supported by a reticle table to form a patterned radiation beam, wherein the radiation beam causes heating of an exposed area of ​​the reticle; and a reticle cooling device configured to remove heat from the reticle, wherein the reticle cooling device comprises: a cooling element disposed below the reticle and adjacent to the exposed area, wherein: The cooling element includes a body comprising a chamber connected to a channel configured to deliver gas to a cavity, a roof of the cavity being disposed adjacent to the photomask and including an opening configured to output the gas toward the photomask; actuators configured to modify a distance between the roof and the photomask; and a cooling controller configured to: generate a cooling control signal based on timing data for a projection of the patterned radiation beam, absorption data for the exposed area on the photomask, and a target heat transfer rate, wherein the cooling control signal is configured to instruct the photomask cooling device to actuate the actuators to modify the distance between the roof and the photomask; and transmit the cooling control signal to the actuators.

2. The lithography apparatus of claim 1, wherein the distance between the top and the magnifying mask is between about 50 micrometers and about 100 micrometers, and the cooling element is separated from the exposed area in a direction corresponding to one of the scanning directions of the lithography apparatus.

3. As in request item 1, the lithography equipment, wherein: The cooling element is a first cooling element; the photomask cooling device includes a pair of cooling elements, the pair of cooling elements including the first cooling element and a second cooling element; the pair of cooling elements are provided on opposite sides of the exposure area; the lithography device includes a scanning lithography device configured to form a curved exposure area; and the pair of cooling elements are curved.

4. The lithography apparatus of claim 3, wherein the first cooling element includes a recessed front edge corresponding to one of the curved exposed areas.

5. The lithography apparatus of claim 3, wherein the first cooling element includes a protruding front edge corresponding to a reflection of the curved exposed area.

6. The lithography apparatus of claim 3, wherein the first cooling element includes a top component that is bent laterally to one of the scanning directions of the lithography apparatus such that the outer end of the top component is closer to the magnifying mask than the central portion of one of the top components.

7. As in request item 3, the lithography device, wherein: The top of the chamber of the body of the cooling element is a first top of the first body of the first chamber of the first cooling element; the openings include a first set of openings defined by the first top; the density of the first set of openings varies along a direction transverse to the scanning direction of the scanning lithography device; and the density of the first set of openings is higher at the outer end of the first top than in the central portion of the first top.

8. The lithography apparatus of claim 1, wherein the cooling element further includes an open cavity provided in one of the uppermost surfaces of the body relative to the magnifying mask.

9. As in request item 1, the lithography device, wherein: The openings comprise a column of apertures or an array of apertures; and the body further comprises at least one movable optical valve configured to selectively close at least a subset of the column of apertures or the array of apertures.

10. The lithography apparatus of claim 1, further comprising: a heat shield positioned between a portion of the cooling element and the photomask, wherein the heat shield is configured to reduce the amount of heat removed from the photomask by the portion of the cooling element from the photomask.

11. As in request item 1, the lithography device, wherein: The channel is a first channel; the photomask cooling device further includes a valve configured to selectively restrict one flow of gas within the first channel; the valve defines a second channel connected between a fluid inlet and a fluid overflow outlet of the first channel; the valve includes a housing portion and a sliding member; the sliding member is slidable between a first position and a second position, in which the second channel is unrestricted and in the second position the second channel is partially restricted; and the sliding member is configured not to physically contact the housing portion.

12. The lithography apparatus of claim 1, further comprising a lithography mask temperature adjustment system configured to adjust a first temperature of one of the lithography masks to a second temperature higher than the first temperature before the lithography mask is placed on the lithography mask stage, wherein the body is flexible to control cooling provided by a portion of the gas disposed between the cooling element and the lithography mask.

13. The lithography apparatus of claim 1, further comprising: a heating device configured to heat the magnifying mask, wherein: The heating device includes a pair of heating elements, which include a first heating element and a second heating element; and the pair of heating elements are configured to heat a magnifying mask area located at opposite ends of the exposed area in a non-scanning direction of the lithography device, wherein the cooling element is in thermal communication with the magnifying mask.

14. A cooling device for a photomask, comprising: a cooling element configured to be disposed below a photomask supported by a photomask stage and adjacent to an exposed area of ​​the photomask, wherein: The cooling element includes a body having a chamber connected to a channel configured to deliver gas to a cavity, the top of the cavity being configured to be positioned adjacent to the photomask and including an opening configured to output the gas toward the photomask; an actuator configured to modify a distance between the top and the photomask; and a cooling controller configured to: generate a cooling control signal based on timing data generated by the photomask for a projection of a patterned radiation beam, absorption data for the exposed area on the photomask, and a target heat transfer rate, wherein the cooling control signal is configured to instruct the photomask cooling device to actuate the actuators to modify the distance between the top and the photomask; and transmit the cooling control signal to the actuators.

15. A method for cooling a magnifying mask, comprising: generating a cooling control signal by means of a cooling controller based on timing data for a projection of a patterned radiation beam, absorption data for an exposed area, and a target heat transfer rate, the patterned radiation beam being formed by irradiating the exposed area on a magnifying mask supported by a magnifying mask stage, wherein the cooling control signal instructs a magnifying mask cooling device to actuate actuators to modify a distance between the magnifying mask and a top of a chamber connected to a channel for delivering gas to a chamber, the channel being located in a body of a cooling element of the magnifying mask cooling device; transmitting the cooling control signal by the cooling controller to the actuators; and modifying the distance between the magnifying mask and the top by the actuators based on the cooling control signal to modify a heat transfer rate associated with the removal of heat from the magnifying mask to the target heat transfer rate.

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