Lithographic apparatus and associated method

Abstract

A lithographic method includes forming an image of a reticle multiple times on a substrate. Each such image forming process includes: irradiating a reticle and a first portion of a pellicle with a radiation beam; and collecting the radiation scattered by the reticle and projecting the radiation onto a target area of the substrate using projection optics. The lithographic method further includes periodically illuminating the reticle and a second portion of the pellicle with the radiation beam, the reticle and the second portion of the pellicle at least partially surrounding the first portion. Some pellicles are susceptible to hydrogen etching, and such pellicles tend to fail in areas surrounding the central portion. Advantageously, hydrogen etching of the reticle and the second portion of the pellicle can be suppressed by periodically irradiating the reticle and the second portion of the pellicle with a radiation beam.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to European application 23168209.7 filed on April 17, 2023 and European application 23188348.9 filed on July 28, 2023, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present invention relates to an apparatus for handling or using a reticle and pellicle assembly for use in an extreme ultraviolet (EUV) lithographic apparatus and related methods. The present invention also relates to a reticle which can be particularly suitable for use in an apparatus and method for handling a reticle and pellicle assembly. The present invention further relates to a pellicle for use in a lithographic apparatus. The present invention further relates to a lithographic apparatus. BACKGROUND

[0004] A lithographic apparatus is a machine that is constructed to apply a desired pattern onto a substrate. For example, the lithographic apparatus can be used in the manufacture of integrated circuits (IC). For example, the lithographic apparatus can project a pattern from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) that is provided on a substrate.

[0005] The wavelength of the radiation used by the lithographic apparatus to project a pattern onto a substrate determines the minimum size of features that can be formed on the substrate. Lithographic apparatuses that use EUV radiation (i.e., electromagnetic radiation having a wavelength within a range of 4-20 nm) can be used to form smaller features on a substrate than those formed by using conventional lithographic apparatuses, which can use electromagnetic radiation with a wavelength of 193 nm.

[0006] A patterning device (e.g., a mask) used to impart a pattern to a beam of radiation in a lithographic apparatus can form part of a mask assembly. The mask assembly can include a pellicle to protect the patterning device from particle contamination. The pellicle can be supported by a pellicle frame.

[0007] It can be desirable to provide an apparatus which obviates or mitigates one or more problems associated with prior art. SUMMARY

[0008] According to a first aspect of the present disclosure, there is provided a lithographic method, the lithographic method comprising: forming an image of a reticle on a substrate a plurality of times, each such image forming process comprising: illuminating a first portion of a reticle and pellicle assembly with a beam of radiation; and collecting radiation scattered by the reticle and projecting the radiation onto a target area of the substrate using projection optics; and periodically illuminating a second portion of the reticle and pellicle assembly with a beam of radiation, the second portion of the reticle and pellicle assembly at least partially encircling the first portion.

[0009] The lithographic method according to the first aspect is advantageous, as will now be discussed.

[0010] Any contamination on the reticle will typically alter the image formed on the substrate, resulting in a print error. To avoid particle contamination of the reticle, it is known to use a thin membrane, referred to as a pellicle, to protect the reticle. The pellicle is disposed in front of the reticle and prevents particles from falling on the reticle. The pellicle is disposed such that it is not sharply imaged onto the substrate (e.g. a wafer coated with resist) and thus particles on the pellicle are less likely to interfere with the imaging process than particles on the reticle. One particularly promising material for use as a pellicle membrane in EUV lithography apparatuses is carbon nanotube (CNT) fabric, which can provide very high EUV transmissivity (greater than 98%) and very good mechanical stability. However, a low pressure of hydrogen gas is typically disposed within the lithography apparatus, which forms a hydrogen plasma in the presence of EUV radiation (during exposure). It has been found that such hydrogen ions and hydrogen radicals from the hydrogen plasma can etch the pellicle formed of CNT, limiting the possible lifetime of the pellicle and blocking commercial implementation of CNT pellicles.

[0011] It has been found that the etching of carbon by hydrogen ions and radicals is temperature dependent. In particular, it has been found that: (a) the carbon etch rate is non-zero at lower temperatures; (b) the carbon etch rate drops to a negligible level at a threshold temperature, above which the carbon etch remains at a negligible level; and (c) a pellicle within an EUV lithography scanner will typically cycle through a temperature range of sample temperatures, within which the carbon etch rate is not negligible during each cycle. For example, in an EUV lithography scanner, during operation, the EUV radiation beam is scanned back and forth over the pellicle, which results in permanent temperature fluctuations.

[0012] It has also been found that, once the pellicle has been heated above the threshold level at which hydrogen etching becomes negligible, there is a time delay before the etch rate increases from the negligible level once heating is removed. It is believed that heating to a sufficient temperature causes hydrogen to desorb from the pellicle, which reduces the hydrogen etch rate to a negligible level. Furthermore, it is believed that there is a time delay in the increase in etch rate after removal of heating, because after heating, the surface of the pellicle takes a non-zero time to replenish with hydrogen.

[0013] The first portion of the reticle and pellicle assembly is the portion that is irradiated with (EUV) radiation to form an image of the reticle on a substrate. Thus, the first portion of the reticle and pellicle assembly can comprise the image forming portion of the reticle and the corresponding portion of the pellicle. During each image forming process, the first portion of the reticle and pellicle assembly is exposed to EUV radiation. This will result in heating of the first portion of the reticle and pellicle assembly (each portion of the first portion of the reticle and pellicle assembly will be heated periodically for a lithographic scanner, with the rate at which the image is formed giving the periodicity, i.e. once per die). As will be appreciated by the skilled person, within a lithographic apparatus, a hydrogen plasma is formed from the EUV radiation (used to expose a substrate). Thus, a hydrogen plasma is formed in the vicinity of the first portion of the reticle and pellicle assembly, which is exposed to and heated by the EUV radiation. It will also be appreciated that the plasma can extend to surrounding areas which are not directly heated by the EUV radiation. As a result, the inventors have found that the pellicle tends to fail in the region surrounding the central portion (the central portion corresponding to the image forming portion).

[0014] Advantageously, by periodically irradiating the second portion of the reticle and pellicle assembly with the beam of radiation, hydrogen etching of the second portion of the reticle and pellicle assembly (the second portion of the reticle and pellicle assembly at least partially surrounds the first portion) can be inhibited.

[0015] It will be appreciated that, as used herein, the second portion partially surrounds the first portion is intended to mean that the second portion is adjacent to the first portion. It will be appreciated that, as used herein, the second portion is adjacent to the first portion is intended to mean that the first portion and the second portion are in contact or share a common boundary for at least a portion of the first portion. The second portion can extend along and be adjacent to at least one side of the first portion (the first portion can be substantially rectangular). The second portion can extend along and be adjacent to more than one side of the first portion (the first portion can be substantially rectangular). In some embodiments, the second portion can completely surround the first portion. That is, the second portion can extend along and be adjacent to all (four) sides of the first portion (the first portion can be substantially rectangular).

[0016] By periodically irradiating an enlarged exposure field, periodically irradiating the second portion of the reticle and pellicle assembly with the beam of radiation can be achieved.

[0017] The exposure field is the area of the reticle and pellicle assembly that is exposed to radiation. It will be appreciated that the extent of the exposure field in the non-scan direction can be defined by the extent of the radiation beam in the non-scan direction (which can be defined by a pair of masking blades). It will be appreciated that the extent of the exposure field in the scan direction can be defined by both the extent of the radiation beam in the scan direction (which can be defined by a pair of masking blades) and the extent of the scan motion.

[0018] Such irradiation of the enlarged field can be part of the exposure of a target region of the substrate (i.e. part of the image forming process). Alternatively, the irradiation of the enlarged field can be between exposures of two target regions of the substrate (i.e. between two image forming processes). For example, the irradiation of the enlarged field can occur between exposures of different target regions (or dies) of a single substrate, or even between exposures of different substrates.

[0019] By varying the exposure field, it is possible to periodically irradiate the reticle and pellicle assembly with the radiation beam using the second portion.

[0020] It will be appreciated that the extent and / or position of the exposure field can be varied.

[0021] The exposure field used for at least some of the image forming processes can be different to the exposure field used for a previous image forming process.

[0022] At least one edge of the exposure field used for each of at least some of the image forming processes can be shifted by an offset.

[0023] For example, the offset can be approximately 50 pm. At least one of the edges of the exposure field can be stepped by such an offset every n exposures (e.g. every exposure). In some embodiments, all of the edges of the exposure field can be stepped by such an offset. The method can use, for example, approximately five different positions for each edge of the exposure field, and the position of each edge of the exposure field can be stepped or cycled through all (e.g. five) of the different positions.

[0024] The exposure field used for a plurality of image forming processes can vary continuously.

[0025] For example, the position of at least one edge of the exposure field can vary continuously. For example, the position of at least one edge of the exposure field can oscillate over a range of positions about a nominal position. The amplitude of such oscillation can be approximately 100 pm. In some embodiments, all of the edges of the exposure field can vary continuously.

[0026] During each image forming process, at least one masking blade can be used in order to mask an adjacent target region of the substrate from being irradiated by the radiation beam.

[0027] Preferably, four shielding blades can be used to define the exposure area and shield adjacent target areas on all four sides of the exposure area. The exposure field can be defined by the exposure area, the scan length, and the positions of the four shielding blades.

[0028] In some embodiments, by controlling at least one shielding blade, an expanded exposure field or a modified exposure field can be achieved.

[0029] The position of at least one masking blade can be manipulated so that the perimeter of the exposure area expands over the extended area.

[0030] For example, the perimeter of the exposure area can be spread out over an area with a size of approximately 100 μm.

[0031] In some embodiments, four masking blades may be used during exposure of each target area to define the exposure field, and for each target area adjacent to the edge of the substrate, at least one masking blade corresponding to the edge of the exposure field adjacent to the edge of the substrate may be positioned to expand the exposure field.

[0032] The target region adjacent to the edge of the substrate can be referred to as an edge target region or an edge die. It will be understood that such an edge target region does not have adjacent target regions on all sides. Instead, on at least one side (adjacent to the edge of the substrate), each edge target region has no adjacent neighboring target region. For such edge target regions (or dies) on the substrate, masking blades can be positioned to expand the exposure area. For example, for such edge target regions (or dies) on the substrate, the masking blades can be shifted by 1 mm or more relative to a nominal position to expand the exposure area. Advantageously, this will result in the irradiation of a portion of the mask and coating assembly adjacent to a first portion of the mask and coating assembly using a radiation beam. If the masking blades are controlled in this manner for all such edge dies, then a portion of the mask and coating assembly substantially surrounding the first portion of the mask and coating assembly can be irradiated using radiation.

[0033] Images formed multiple times on a substrate can include images formed on multiple target regions of the substrate. Each of these multiple target regions can be approximately rectangular. These multiple target regions can be arranged in a two-dimensional array.

[0034] In some embodiments, a standard zigzag scanning pattern can be used to expose a two-dimensional array of target regions, wherein each row of target regions (extending in the non-scanning direction) is exposed sequentially. One target region from each row has no adjacent target region on one side, while another target region has no adjacent target region on the other side. Therefore, with this arrangement, portions of the mask and film assembly adjacent to a first portion of the mask and film assembly but offset in the non-scanning direction can be exposed to radiation during the exposure of each row. Conversely, during the exposure of the first half of the substrate, there are some target regions that have no adjacent target regions on a first side in the scanning direction, but no target regions that have no adjacent target regions on another (second) side in the scanning direction. Similarly, during the exposure of the first half of the substrate, there are some target regions that have no adjacent target regions on a second side in the scanning direction, but no target regions that have no adjacent target regions on a first side in the scanning direction.

[0035] In some embodiments, an exposure pattern can be used to expose a two-dimensional array of target regions in which multiple rows of target regions (extending in the non-scanning direction) are exposed in different orders in order to increase the frequency at which target regions that have no adjacent target regions on a first or second side in the scanning direction are increased.

[0036] Images formed multiple times on a substrate can include: images formed on multiple target regions of the substrate, the multiple target regions being arranged in a two-dimensional array, wherein the two-dimensional array of target regions is exposed one row at a time, and wherein the rows are exposed out of order.

[0037] Each image formation process may include a scanning exposure, in which the mask and coating assembly are moved relative to the radiation beam in the scanning direction.

[0038] In embodiments where an expanded exposure field is periodically irradiated, radiation scattered from the mask and film assembly from the expanded exposure field may not be projected onto the substrate.

[0039] For example, in some embodiments, the substrate can be moved such that radiation scattered from the mask and the film assembly does not incident on the substrate. Alternatively, in some embodiments, the baffle can be closed to prevent radiation scattered from the mask and the film assembly from incident on the substrate.

[0040] Generally, the duration for which the radiation beam periodically irradiates the mask and the second portion of the film assembly can be sufficiently long to heat the second portion of the film to a desired temperature (e.g., above a threshold temperature where hydrogen etching of the film can be negligible). In some embodiments, the desired temperature can be above 900 K. It will be understood that the time required to heat the film to the desired temperature will depend on the power of the radiation beam while it is heating the film.

[0041] The process of periodically irradiating a second portion of a mask and a film assembly with a radiation beam may include exposing the second portion to EUV radiation to heat the film to a temperature at which the hydrogen etching rate of the film can be neglected.

[0042] For example, periodically irradiating a second portion of a mask and a film assembly with a radiation beam may include exposing the second portion to EUV radiation to heat the film to a temperature above 800 K, such as above 900 K.

[0043] Generally, the time interval between two consecutive irradiations of the mask and the second portion of the coating assembly using a radiation beam can be small enough to prevent the surface of the coating from being replenished with hydrogen after the heating from the first irradiation. Furthermore, it will be understood that the time required for the surface of the coating to be replenished with hydrogen after the heating from the first irradiation will depend on the conditions near the coating. In some embodiments, the time interval between two consecutive irradiations of the mask and the second portion of the coating assembly can be approximately 100 ms.

[0044] Periodically irradiating the second portion of the mask and the coating assembly with a radiation beam allows the second portion of the mask and the coating assembly to be irradiated once for each substrate.

[0045] The second part of the mask and the film assembly can be periodically irradiated with a radiation beam so that the second part of the mask and the film assembly is irradiated once for each row of target areas on the substrate.

[0046] According to a second aspect of this disclosure, a lithography component of a lithography apparatus is provided, the lithography component comprising: a support structure configured to support a mask and a surface coating assembly for receiving a radiation beam; and a controller operable to control the support structure and / or the radiation beam such that: (a) an image of the mask supported by the support structure is formed multiple times on a substrate, each such image forming process comprising: irradiating a first portion of the mask and the surface coating assembly with the radiation beam; and projecting radiation scattered by the mask onto a target area of ​​the substrate using projection optics; and (b) periodically irradiating a second portion of the mask and the surface coating assembly with the radiation beam, the second portion of the mask and the surface coating assembly at least partially surrounding the first portion.

[0047] The lithography component according to the second aspect is advantageous, as now discussed.

[0048] As discussed above, a diaphragm placed in front of the photomask prevents particles from falling onto the mask, which can improve optical performance (by reducing printing errors). One particularly promising material for use as a diaphragm in EUV lithography equipment is a fabric of carbon nanotubes (CNTs); however, CNT diaphragms are susceptible to hydrogen etching. It has been found that etching of carbon by hydrogen ions and free radicals decreases to a negligible level at a threshold temperature, and above this threshold temperature, carbon etching remains negligible. It has also been found that once the diaphragm has been heated above the threshold level (where hydrogen etching becomes negligible), there is a time lag before the etching rate increases from a negligible level once the heating is removed.

[0049] The first portion of the mask and coating assembly is the part irradiated by (EUV) radiation to form an image of the mask on the substrate. Therefore, the first portion of the mask and coating assembly can include the image-forming portion of the mask and the corresponding portion of the coating. During each image-forming process, the first portion of the mask and coating assembly is exposed to EUV radiation. This results in heating of the first portion of the mask and coating assembly (for a lithography scanner, each segment or portion of the first portion of the mask and coating assembly will be periodically heated, with the periodicity determined by the rate at which the image is formed, i.e., once per die). As those skilled in the art will understand, within a lithography apparatus, hydrogen plasma is formed by EUV radiation (used for exposing the substrate). Therefore, hydrogen plasma forms near the first portion of the mask and coating assembly, which is exposed to and heated by EUV radiation. It will also be understood that the plasma can extend into surrounding areas not directly heated by EUV radiation. As a result, the inventors have found that the film tends to fail in the area surrounding the central portion (which corresponds to the image-forming portion).

[0050] Advantageously, hydrogen etching of the second portion of the mask and the film assembly (which at least partially surrounds the first portion) can be suppressed by periodically irradiating the second portion of the mask and the film assembly with a radiation beam.

[0051] The controller is capable of operating to implement the method according to the first aspect disclosed.

[0052] The lithography apparatus may also include a scanning mechanism that is operable to move the support structure relative to the radiation beam in the scanning direction.

[0053] The scanning mechanism can also be operated to move the substrate stage of the lithography apparatus relative to the projection system of the lithography apparatus, such that the image of the mask formed by the projection system is substantially stationary relative to the substrate. This can be described as the synchronous movement of the support structure and the substrate stage. The movement (direction and speed) of the substrate stage relative to the support structure will generally depend on the image inversion and magnification characteristics of the projection system.

[0054] The controller is capable of operating to control the scanning mechanism.

[0055] The photolithography apparatus may further include: a first pair of masking blades arranged to define the exposure area in a first direction; and a second pair of masking blades arranged to define the exposure area in a second direction.

[0056] The first pair of masking blades and the second pair of masking blades can be movable to change the extent of the exposure area. The controller is operable to control the position of each of the first pair of masking blades and the second pair of masking blades, or each pair of masking blades. In use, two pairs of masking blades can be used to define the exposure area and mask adjacent target areas on all four sides of the exposure area.

[0057] The first direction can be the scanning direction, and in order to form an image of a mask supported by a support structure on a target area of ​​the substrate, the controller can operate to: control the scanning mechanism to move the mask supported by the support structure through the exposure area; and control the position of the first pair of shielding blades to shield adjacent target areas of the substrate from being irradiated by the radiation beam.

[0058] As the target area of ​​the substrate moves into the exposure area, the first pair of shielding blades moves such that only the target area receives radiation (i.e., any part of the substrate outside the target area is not exposed). At the start of the scan exposure, one of the shielding blades in the first pair is positioned in the path of the radiation beam as a baffle, ensuring that no part of the substrate receives radiation. At the end of the scan exposure, the other shielding blade in the first pair is positioned in the path of the radiation beam as a baffle, ensuring that no part of the substrate receives radiation. During the middle portion of the scan exposure, when there is no overlap between the exposure area (where radiation is received) and any adjacent target area of ​​the substrate, both shielding blades in the first pair are positioned in the retracted position.

[0059] In order to irradiate the second part of the mask and film assembly with a radiation beam, the controller can be operated to control the first pair of shielding blades and / or the second pair of shielding blades to irradiate an expanded exposure field.

[0060] The exposure field is the area of ​​the mask and film assembly exposed to radiation. It will be understood that the extent of the exposure field in the non-scanning direction can be defined by the extent of the radiation beam in the non-scanning direction (which can be defined by a pair of shielding blades). It will be understood that the extent of the exposure field in the scanning direction can be defined by both the extent of the radiation beam in the scanning direction (which can be defined by a pair of shielding blades) and the range of the scanning motion.

[0061] Irradiation of such an expanded field can be part of the exposure of a target area of ​​the substrate (i.e., part of the image formation process). Alternatively, irradiation of the expanded field can occur between exposures of two target areas of the substrate (i.e., between two image formation processes). For example, irradiation of the expanded field can occur between exposures of different target areas (or dies) of a single substrate, or even between exposures of different substrates.

[0062] In order to irradiate the second part of the mask and film assembly with a radiation beam, the controller can be operated to control the first pair of shielding blades and / or the second pair of shielding blades to change the exposure field.

[0063] It will be understood that the range and / or position of the exposure field can be changed.

[0064] The controller is operable to control a first pair of masking blades and / or a second pair of masking blades such that the exposure field used for at least some image forming processes is different from the exposure field used for previous image forming processes.

[0065] For example, the controller can operate to control the first pair of masking blades and / or the second pair of masking blades such that at least one edge of the exposure field for each of the at least some image forming processes is shifted by an offset.

[0066] For example, the offset could be approximately 50 μm. At least one edge of the exposure field can be stepped with such an offset every n exposure cycles (e.g., each exposure cycle). In some embodiments, all edges of the exposure field can be stepped with such an offset. The method implemented by the controller can use, for example, approximately five different positions for each edge of the exposure field, and can make the position of each edge of the exposure field step or cycle through all (e.g., the five) different positions.

[0067] The controller is operable to control the first pair of masking blades and / or the second pair of masking blades, so that the exposure field for multiple image forming processes changes continuously.

[0068] For example, the position of at least one edge of the exposure field can vary continuously. For example, the position of at least one edge of the exposure field can oscillate at some locations around a nominal position. The amplitude of such oscillation can be approximately 100 μm. In some embodiments, all edges of the exposure field can vary continuously.

[0069] In order to irradiate the second part of the mask and the film assembly with the radiation beam, the controller can be operated to control the first pair of shielding blades and / or the second pair of shielding blades so that the perimeter of the exposure area unfolds over the extended area.

[0070] For example, the perimeter of the exposure area can be spread out over an area with a size of approximately 100 μm.

[0071] In order to irradiate a second part of the mask and the film assembly with a radiation beam, the controller is operable to control a first pair of masking blades and / or a second pair of masking blades such that when an image of the mask supported by the support structure is formed on a target area adjacent to the edge of the substrate, at least one masking blade of the masking blades corresponding to the edge adjacent to the edge of the substrate of the exposure field can be positioned to expand the exposure field.

[0072] The target region adjacent to the edge of the substrate can be referred to as an edge target region or an edge die. It will be understood that such an edge target region does not have adjacent target regions on all sides. Instead, on at least one side (adjacent to the edge of the substrate), each edge target region has no adjacent neighboring target region. For such edge target regions (or dies) on the substrate, masking blades can be positioned to expand the exposure area. For example, for such edge target regions (or dies) on the substrate, the masking blades can be shifted by 1 mm or more relative to their nominal position to expand the exposure area. Advantageously, this will result in the irradiation of a portion of the mask and coating assembly adjacent to a first portion of the mask and coating assembly using a radiation beam. If the masking blades are controlled in this manner for all such edge dies, then a portion of the mask and coating assembly substantially surrounding the first portion of the mask and coating assembly can be irradiated using radiation.

[0073] Images formed multiple times on a substrate can include images formed on multiple target regions of the substrate. Each of these multiple target regions can be approximately rectangular. These multiple target regions can be arranged in a two-dimensional array.

[0074] Generally, the duration for which the radiation beam periodically irradiates the mask and the second portion of the film assembly can be sufficiently long to heat the second portion of the film to a desired temperature (e.g., above a threshold temperature where hydrogen etching of the film can be negligible). In some embodiments, the desired temperature can be above 900 K. It will be understood that the time required to heat the film to the desired temperature will depend on the power of the radiation beam while it is heating the film.

[0075] When the mask and the second part of the film assembly are irradiated with a radiation beam, the controller can operate to heat the film to a temperature at which the hydrogen etching rate of the film can be negligible.

[0076] For example, the controller can be operated to heat the film to a temperature above 800 K, such as above 900 K.

[0077] According to a third aspect of this disclosure, a photolithography apparatus including components of the second aspect of this disclosure is provided.

[0078] The lithography apparatus may further include: an irradiation system configured to modulate a radiation beam received by the mask and the coating assembly; a substrate stage configured to support a substrate; and a projection system configured to receive the radiation beam from the mask and the coating assembly and project the radiation beam onto the substrate.

[0079] According to a fourth aspect of this disclosure, a surface film for use in a photolithography apparatus is provided, the surface film comprising a frame and a septum, the septum being surrounded and supported by the frame; wherein the septum is generally flat and defines a plane of the surface film; wherein the frame has a thickness generally perpendicular to the plane of the surface film and a width generally parallel to the plane of the surface film; and wherein, in the plane of the surface film, an outer portion of the frame contacts the septum, and along at least one edge of the septum, an inner portion of the frame has a reduced thickness relative to the outer portion of the frame, such that the inner portion of the frame does not contact the septum.

[0080] In use, the diaphragm will receive a heat load from the radiation used by the lithography equipment (e.g., EUV radiation), while the frame will remain at a lower temperature. Due to the presence of the frame (which has greater thermal inertia than the diaphragm due to its larger size), the area of ​​the diaphragm in contact with the frame has a reduced temperature. The surface film according to the fourth aspect of this disclosure is advantageous because it allows the contact portion between the frame and the diaphragm to move outward along at least one edge of the diaphragm without reducing the width of the frame (i.e., the size of the frame that is generally parallel to the plane of the surface film). This allows the frame to maintain a similar level of rigidity while allowing the contact portion between the frame and the diaphragm to move outward. Furthermore, advantageously, by moving the portion of the diaphragm in contact with the frame (and in use, this portion of the diaphragm in contact with the frame at a lower temperature than the rest of the diaphragm) outward, the diaphragm is exposed to less or even no high-intensity EUV-induced hydrogen plasma.

[0081] The recess formed between the inner portion of the frame, which has a reduced thickness, and the diaphragm can have a substantially uniform thickness.

[0082] Alternatively, the recess formed between the inner portion of the frame with a reduced thickness and the diaphragm may have a thickness that varies from the inner edge of the frame to the outer portion of the frame.

[0083] It will be understood that the width of the internal portion of the frame with a reduced thickness can be selected such that the portion of the diaphragm in contact with the frame (and in use, the portion of the diaphragm in contact with the frame is at a lower temperature than the rest of the diaphragm) is not adjacent to high-intensity EUV-induced hydrogen plasma.

[0084] The width of the internal sub-section of the frame, which has a reduced thickness, can be greater than 2 mm.

[0085] The width of the inner portion of the frame with reduced thickness can be greater than 2.2 mm. In some embodiments, the width of the inner portion of the frame with reduced thickness can be approximately 2.5 mm.

[0086] According to a fifth aspect of this disclosure, a photolithography apparatus is provided, the photolithography apparatus comprising: a surface film including a frame and a diaphragm surrounded and supported by the frame; a hydrogen source; and an irradiation system arranged to irradiate the surface film with radiation; wherein a portion of the diaphragm in contact with the frame is disposed at a location where EUV-induced hydrogen plasma does not diffuse.

[0087] Advantageously, because the portion of the diaphragm in contact with the frame is positioned where the EUV-induced hydrogen plasma does not diffuse, the diaphragm undergoes less etching from the plasma. The surface film of the photolithography apparatus according to the fifth aspect of this disclosure may include the surface film according to the fourth and / or sixth aspects of this disclosure.

[0088] According to a sixth aspect of this disclosure, a surface film for use in a photolithography apparatus is provided, the surface film comprising: a frame; a diaphragm surrounded and supported by the frame; and a shielding member adjacent to a peripheral portion of the diaphragm adjacent to the frame; wherein the diaphragm is generally flat and defines a plane of the surface film; and wherein the shielding member is spaced apart from the diaphragm in a direction generally perpendicular to the plane of the surface film.

[0089] The coating according to the sixth aspect of this disclosure is advantageous because the shielding member can protect the coating from etching by plasma (e.g., EUV-induced hydrogen plasma) during use (e.g., in an EUV lithography apparatus).

[0090] The conventional idea might be that masking blades can be used as plasma shielding for the surface film. However, it has recently been found that the most etched areas on the CNT separator lie below the masking blades outside the exposure area (indicating that the masking blades do not provide effective plasma shielding for the surface film). It is believed that the distance between the masking blades and the surface film separator is too large to provide effective shielding. Although in use, there is typically not a large space between the surface film separator and other components (e.g., masking blades), it is believed that sufficient space exists for a relatively thin shield, thus allowing the surface film according to the sixth aspect of this disclosure to be used in existing lithography equipment.

[0091] The shielding element may extend beyond the boundary of the mask, but remains outside the quality area (or a portion of the mask corresponding to the image-forming area of ​​the mask).

[0092] The membrane according to the sixth aspect of this disclosure may, as needed, include any features of the membrane according to the fourth aspect of this disclosure.

[0093] The shielding member may include a first shielding member adjacent to a first surface of a peripheral portion of the diaphragm, and a second shielding member adjacent to a second surface of a peripheral portion of the diaphragm.

[0094] The first surface can be the surface of the film that faces away from the photomask during use (and can be referred to as the upper surface or front surface of the film). The second surface can be the surface of the film that faces the photomask during use (and can be referred to as the lower surface or rear surface of the film).

[0095] It may be desirable for the shield to be as close as possible to the surface of the diaphragm, as this minimizes the amount of plasma diffusing beneath the shield (i.e., between the shield and the diaphragm), thus maximizing plasma shielding. Typically, it may be desirable for the distance between the shield and the diaphragm surface to be less than the Debye length of the plasma (which can be less than 1 mm, or less than 0.2 mm during EUV pulses). It may also be desirable for the shield to be far enough from the diaphragm surface to allow for any diaphragm sagging without the risk of the shield contacting the diaphragm surface.

[0096] It will be understood that, in embodiments where the shielding includes a first shielding member and a second shielding member, the first shielding member and the second shielding member can be positioned at different distances from the diaphragm. Alternatively, the first shielding member and the second shielding member can be positioned at substantially the same distance from the diaphragm.

[0097] The distance between the shield and the diaphragm can be less than 1 mm. For example, the distance between the surface of the shield and the diaphragm can be between 200 μm and 1000 μm. For example, the distance between the surface of the shield and the diaphragm can be between 400 μm and 800 μm.

[0098] It will be understood that the distance between the first shielding member and the diaphragm can be less than 1 mm, and / or the distance between the second shielding member and the diaphragm can be less than 1 mm. In particular, the distance between the front surface of the diaphragm and the shielding member adjacent to the front surface of the diaphragm can be less than 1 mm.

[0099] The shielding element can have a thickness of less than 1 mm. The shielding element can have a thickness between approximately 100 μm and 300 μm. The shielding element can have a thickness of approximately 200 μm or less. The thickness of the shielding element can be selected to be readily available commercially.

[0100] The shield can extend approximately 1 mm to 1.5 mm away from the frame in a plane parallel to the diaphragm.

[0101] Preferably, the shield can extend to cover a portion of the diaphragm that would be adjacent to the plasma but not receive EUV radiation during use in the absence of the shield. The shield can remain approximately 0.5 mm to 1.5 mm away from the quality area of ​​the diaphragm (i.e., the portion of the diaphragm corresponding to the image-forming area of ​​the mask), so that the shield does not interfere with the EUV beam.

[0102] The shielding element can be formed of a material that is transparent to the wavelength of radiation used to periodically heat the diaphragm during use.

[0103] For example, the shield can be formed of a material that is transparent to infrared (IR) and / or deep ultraviolet (DUV) radiation. This allows the shield to protect the diaphragm from the effects of plasma while still allowing the use of this radiation to periodically heat the diaphragm.

[0104] The shielding element can be formed from a material that is inert in hydrogen plasma.

[0105] Shielding components may include sapphire (Al2O3).

[0106] For example, the shielding element may include a glass material coated with sapphire (Al2O3). Alternatively, the shielding element may be formed of sapphire.

[0107] According to a seventh aspect of this disclosure, a photolithography apparatus is provided, the photolithography apparatus comprising: a surface film, the surface film including: a frame, a diaphragm surrounded and supported by the frame, and a shield adjacent to a peripheral portion of the diaphragm adjacent to the frame; a hydrogen source; and an irradiation system arranged to irradiate the surface film with radiation; wherein the shield is adjacent to a portion of the diaphragm to which EUV-induced hydrogen plasma would diffuse without such a shield.

[0108] Advantageously, since the shielding element is adjacent to a portion of the diaphragm to which EUV-induced hydrogen plasma would diffuse without it, the shielding element protects the diaphragm from the plasma (and associated plasma etching) that would be present without it. The surface film of the lithography apparatus according to the seventh aspect of this disclosure may include the surface film according to the fourth and / or sixth aspects of this disclosure.

[0109] It will be understood that one or more aspects or features described above or mentioned below may be combined with one or more other aspects or features. Attached Figure Description

[0110] Embodiments of the invention will now be described by way of example only with reference to the accompanying schematic drawings, in which:

[0111] - Figure 1 It is a schematic diagram of a lithography system that includes lithography equipment and a radiation source;

[0112] - Figure 2A It is set in the first end position Figure 1 A schematic plan view of the support structure and pattern forming apparatus shown in the figure;

[0113] - Figure 2B It is set in the second end position Figure 1 A schematic plan view of the support structure and pattern forming apparatus shown in the figure;

[0114] - Figure 3A Is it through Figure 1 A schematic diagram of the pattern forming device and the first cross section of the mask-covering blade on the support structure of the lithography equipment;

[0115] - Figure 3B Is it through Figure 1 A schematic diagram of the pattern forming device and the second cross section of the mask-shielding blade on the support structure of the lithography equipment;

[0116] - Figure 4 It is shown that the first configuration is presented Figure 1 A plan view of the y-masking blades and x-masking blades (dashed lines) of a photolithography device;

[0117] - Figure 5 The diagram shows the values ​​for four different ion energies: 5 eV, 10 eV, 20 eV, and 30 eV, for 1.5 • 10 eV. 19 m -2 •s -1 The hydrogen ion flux, the expected etching rate of hydrogen etching of carbon as a function of temperature; Figure 5 It also shows the functional relationship between sp3 carbon concentration and temperature;

[0118] - Figure 6 It is a schematic qualitative diagram showing the relationship between the hydrogen etching rate and the time after heating to the temperature at which the hydrogen etching becomes negligible once the heating is removed.

[0119] - Figure 7 This is a schematic illustration of a novel photolithography method according to embodiments of the present disclosure;

[0120] - Figure 8 It is possible Figure 7 A schematic plan view of the mask and film assembly used in the photolithography method;

[0121] - Figure 9 A graph showing the relationship between the change in resist height on a wafer exposed to EUV radiation via a surface film and the non-scanning position (x position) is presented, indicating the relationship between the EUV transmittance of the CNT surface film and the non-scanning position (x position).

[0122] - Figure 10 It shows Figure 7 A flowchart of the first embodiment of the method shown;

[0123] - Figure 11A The illustration shows a standard photolithography method in which a standard exposure field is used n*m times to form an image on a target area on a substrate;

[0124] - Figure 11B The diagram shows... Figure 10 The photolithography method shown involves using a standard exposure field n times to form an image on a target area on a substrate, followed by an enlarged exposure field once; this process of n+1 exposures is repeated m times.

[0125] - Figure 12 It shows Figure 7 A flowchart of the second embodiment of the method shown;

[0126] - Figure 13 A graph showing the relationship between the change in resist height on a wafer exposed to EUV radiation via a surface film and the non-scanning position (x-position) at the mask level is shown, the graph for (a) standard photolithography method (solid line); (b) Figure 12 A novel photolithography method indicates the functional relationship between the EUV transmittance of the CNT surface film and the non-scanning position (x position), wherein the shielding blades are stepped in 10 steps of 2 mm each (dashed line).

[0127] - Figure 14 It shows Figure 7 A flowchart of the third embodiment of the method shown;

[0128] - Figure 15 It is a schematic plan view representation of a substrate comprising multiple (generally rectangular) target regions or dies (generally circular); it also shows a standard zigzag scan pattern in which each row of target regions (extending in the non-scanning direction) is exposed sequentially, wherein the exposure order of the target regions is indicated by a number on each target region, the scan direction of the exposure of each target region is indicated by a solid arrow, and the movement of the substrate between the exposure of two consecutive target regions is indicated by a dashed line;

[0129] - Figure 16A cross-sectional view shows a portion of the diaphragm of the mask and diaphragm assembly, including the mask, diaphragm frame, and diaphragm. Also shown are: a shielding blade, a portion of the diaphragm that can receive EUV radiation in use, and a portion of the diaphragm that does not receive EUV radiation in use but does receive hydrogen plasma.

[0130] - Figure 17A This is a schematic cross-section of a known portion of the surface film;

[0131] - Figure 17B to Figure 17D It is a schematic cross-section of a portion of three novel membranes, wherein along at least one edge of the diaphragm, the inner portion of the frame has a reduced thickness relative to the outer portion of the frame, such that the inner portion of the frame does not contact the diaphragm.

[0132] - Figure 17E This is a schematic cross-section of a portion of another novel surface film, which is Figure 17A The known film shown is a variant, but with a smaller width than the known film.

[0133] - Figure 18 A novel mask and a mask assembly including a novel surface membrane according to embodiments of the present disclosure are shown. The novel surface membrane is provided with a shield to protect the peripheral portion of the diaphragm from hydrogen plasma etching; and

[0134] - Figure 19 It shows Figure 18 The enlarged portion of the novel mask and film assembly is shown. Detailed Implementation

[0135] Figure 1 A lithography system is shown. The lithography system includes a radiation source SO and a lithography apparatus LA. The radiation source SO is configured to generate an extreme ultraviolet (EUV) radiation beam B. The lithography apparatus LA includes: an irradiation system IL; a support structure MT configured to support a mask assembly 15 including a patterning apparatus MA (e.g., a mask or stencil); a projection system PS; and a substrate stage WT configured to support a substrate W. The irradiation system IL is configured to adjust the radiation beam B before it is incident on the patterning apparatus MA. The projection system is configured to project the radiation beam B (now patterned by the patterning apparatus MA) onto the substrate W. The substrate W may include a previously formed pattern. Under such conditions, the lithography apparatus aligns the patterned radiation beam B with the pattern previously formed on the substrate W.

[0136] The radiation source SO, the irradiation system IL, and the projection system PS can all be constructed and arranged such that the radiation source SO, the irradiation system IL, and the projection system PS can be isolated from the external environment. A gas at a pressure lower than atmospheric pressure (e.g., hydrogen) can be provided in the radiation source SO. A vacuum can be provided in the irradiation system IL and / or the projection system PS. A small amount of gas at a pressure much lower than atmospheric pressure (e.g., hydrogen) can be provided in the irradiation system IL and / or the projection system PS.

[0137] Figure 1 The radiation source SO shown belongs to the type that can be referred to as a laser-generated plasma (LPP) source. A laser 1, which can be, for example, a CO2 laser, is arranged to deposit energy via a laser beam 2 onto a fuel such as tin (Sn), which is supplied by a fuel emitter 3. Although tin is mentioned in the following description, any suitable fuel can be used. The fuel can be, for example, in liquid form and can be, for example, a metal or alloy. The fuel emitter 3 can include a nozzle configured to guide tin, for example, in droplet form, along a trajectory toward the plasma-forming region 4. The laser beam 2 is incident on the tin located at the plasma-forming region 4. The laser energy deposited into the tin generates plasma 7 at the plasma-forming region 4. During the deexcitation and recombination of ions in the plasma, radiation, including EUV radiation, is emitted from plasma 7.

[0138] EUV radiation is collected and focused by a near-normal incident radiation collector 5 (sometimes more generally referred to as a normal incident radiation collector). Collector 5 may have a multilayer structure arranged to reflect EUV radiation (e.g., EUV radiation with a desired wavelength such as 13.5 nm). Collector 5 may have an elliptical configuration with two elliptical foci. As discussed below, the first focal point may be located at plasma formation region 4, and the second focal point may be located at intermediate focal point 6.

[0139] In other embodiments of the laser-generated plasma (LPP) source, collector 5 may be a so-called grazing incidence collector, which is arranged to receive EUV radiation at a grazing incidence angle and focus the EUV radiation at an intermediate focal point. The grazing incidence collector may be, for example, a nested collector comprising multiple grazing incidence reflectors. The grazing incidence reflectors may be arranged symmetrically about an optical axis.

[0140] The radiation source SO may include one or more contaminant traps (not shown). For example, a contaminant trap may be located between the plasma formation region 4 and the radiation collector 5. The contaminant trap may be, for example, a rotating foil trap, or any other suitable form of contaminant trap.

[0141] Laser 1 can be separated from radiation source SO. Under such conditions, laser beam 2 can be transmitted from laser 1 to radiation source SO with the assistance of a beam delivery system (not shown), which includes, for example, suitable directional mirrors and / or beam expanders, and / or other optical components. Laser 1 and radiation source SO can be considered together as a radiation system.

[0142] Radiation reflected by collector 5 forms radiation beam B. Radiation beam B is focused at point 6 to form an image of plasma formation region 4, which serves as a virtual radiation source for irradiating system IL. Point 6 where radiation beam B is focused can be referred to as the intermediate focal point. Radiation source SO is arranged such that intermediate focal point 6 is located at or near opening 8 in the enclosure structure 9 of radiation source SO.

[0143] A radiation beam B is transmitted from a radiation source SO to an irradiation system IL, which is configured to modulate the radiation beam. The irradiation system IL may include a faceted field mirror assembly 10 and a faceted pupil mirror assembly 11. Together, the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11 provide a radiation beam B with a desired cross-sectional shape and a desired angular distribution. The radiation beam B is transmitted from the irradiation system IL and incident on a mask assembly 15 held by a support structure MT. The mask assembly 15 includes a pattern forming device MA and a surface film 19. The surface film is mounted to the pattern forming device MA via a surface film frame 17. The mask assembly 15 may be referred to as a mask and surface film assembly 15. The pattern forming device MA reflects and patternes the radiation beam B. The irradiation system IL may include other mirrors or devices besides or alternatives to the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11.

[0144] After reflection from the patterning apparatus MA, the patterned radiation beam B enters the projection system PS. The projection system includes multiple mirrors 13 and 14 configured to project the radiation beam B onto a substrate W held by a substrate stage WT. The projection system PS can apply a reduction factor to the radiation beam to form an image with features smaller than those on the corresponding features of the patterning apparatus MA. For example, a reduction factor equal to four can be applied. Although in Figure 1 The projection system PS has two mirrors 13 and 14, but the projection system PS can include any number of mirrors (e.g., six mirrors).

[0145] The photolithography apparatus can be used, for example, in a scanning mode, where a support structure (e.g., a mask stage) MT and a substrate stage WT are scanned synchronously while a pattern applied to the radiation beam is projected onto the substrate W (i.e., dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure (e.g., the mask stage) MT can be determined by the scaling and image inversion characteristics of the projection system PS. The patterned radiation beam incident on the substrate W can include a radiation band. The radiation band can be referred to as an exposure slit. During scanning exposure, movement of the substrate stage WT and the support structure MT allows the exposure slit to travel across the exposure field of the substrate W.

[0146] Figure 1 The radiation source SO and / or lithography apparatus shown may include components not illustrated. For example, a spectral filter may be provided in the radiation source SO. The spectral filter may be substantially transmissive to EUV radiation but substantially blocking radiation of other wavelengths, such as infrared radiation.

[0147] In other embodiments of the lithography system, the radiation source SO may take other forms. For example, in an alternative embodiment, the radiation source SO may include one or more free-electron lasers. One or more free-electron lasers may be configured to emit EUV radiation that can be provided to one or more lithography apparatuses.

[0148] As briefly described above, the mask assembly 15 includes a surface film 19 provided adjacent to the patterning apparatus MA. The surface film 19 is provided in the path of the radiation beam B such that the radiation beam B passes through the surface film 19 both when it approaches the patterning apparatus MA from the irradiation system IL and when it is reflected from the patterning apparatus MA toward the projection system PS. The surface film 19 comprises a thin film or membrane that is substantially transparent to EUV radiation (however, the surface film 19 will absorb a small amount of EUV radiation). "EUV-transparent surface film" or "substantially transparent film to EUV radiation" herein means that the surface film 19 is transmissive to at least 65% of EUV radiation, preferably at least 80%, and more preferably at least 90% of EUV radiation. The surface film 19 serves to protect the patterning apparatus MA from particle contamination.

[0149] Although efforts may be made to maintain a clean environment inside the lithography apparatus LA, particles can still be present inside the lithography apparatus LA. In the absence of the surface film 19, particles may deposit onto the patterning apparatus MA. Particles on the patterning apparatus MA may adversely affect the pattern imparted to the radiation beam B and thus affect the pattern transferred to the substrate W. The surface film 19 advantageously provides a barrier between the patterning apparatus MA and the environment within the lithography apparatus LA to prevent particle deposition on the patterning apparatus MA.

[0150] The surface film 19 is positioned at a distance sufficient to prevent any particles incident on the surface of the surface film 19 from being in the field plane of the lithography apparatus LA. This separation between the surface film 19 and the patterning apparatus MA reduces the extent to which any particles on the surface of the surface film 19 impart a pattern to the radiation beam B imaged onto the substrate W. It will be understood that if a particle is present in the radiation beam B but is located at a position not in the field plane of the radiation beam B (e.g., not at the surface of the patterning apparatus MA), any image of the particle will not be focused on the surface of the substrate W. In the absence of other considerations, it might be desirable to position the surface film 19 at a considerable distance from the patterning apparatus MA. However, in practice, the space available in the lithography apparatus LA to accommodate the surface film is limited due to the presence of other components. In some embodiments, the spacing between the surface film 19 and the patterning apparatus MA may be, for example, between approximately 1 mm and 10 mm, for example, between 1 mm and 5 mm, for example, between 2 mm and 2.5 mm.

[0151] The surface film may include a boundary portion and a separator. The boundary portion of the surface film may be hollow and generally rectangular, and the separator may be demarcated by the boundary portion. As is known in the art, the surface film can be formed by depositing one or more thin layers of material on a generally rectangular silicon substrate. During this stage of surface film construction, the silicon substrate supports one or more thin layers. Once a layer of desired or target thickness and composition has been applied, the central portion of the silicon substrate is removed by etching (this may be referred to as back-side etching). The peripheral portion of the rectangular silicon substrate is not etched (or alternatively etched to a degree smaller than the central portion). This peripheral portion forms the boundary portion of the final surface film, while the one or more thin layers form the separator of the surface film (the separator is surrounded by the boundary portion). The boundary portion of the surface film may be formed of silicon.

[0152] Such a surface membrane may require some support from a more rigid surface membrane frame. The surface membrane frame can provide two functions. First, it can support the surface membrane and also tighten the membrane's septum. Second, it can facilitate the connection between the surface membrane and the patterning apparatus (mask). In a known arrangement, the surface membrane frame may include a main, generally rectangular body portion glued to the boundary portion of the surface membrane and titanium attachment mechanisms glued to the sides of this body. An intermediate fixing member (referred to as a stud) is attached to the patterning apparatus (mask). The intermediate fixing member (stud) on the patterning apparatus (mask) can engage (e.g., releasably engage) with the attachment members of the surface membrane frame.

[0153] One particularly promising material for use as the diaphragm of the surface film 19 in EUV lithography equipment is carbon nanotube (CNT) fabric, which can provide very high EUV transmittance (greater than 98%) and very good mechanical stability. However, low-pressure hydrogen gas is typically present within the lithography equipment LA, which forms hydrogen plasma in the presence of EUV radiation B (during exposure of the substrate W). It has been found that these hydrogen ions and hydrogen radicals from the hydrogen plasma can etch the surface film 19 formed by CNTs, thereby limiting the potential lifetime of the surface film 19 and hindering the commercial implementation of CNT surface films.

[0154] Now for reference Figure 2A to Figure 4 Descriptions are provided of some additional features of the lithography apparatus LA of the example type (specifically, some features and components that are similar to those of the support structure MT).

[0155] The support structure MT can move in the scanning direction to expose a larger area of ​​the patterning apparatus MA of the mask and the film assembly 15 in a single dynamic scan exposure, as now referenced. Figure 2A and Figure 2B The discussion. Figure 2A and Figure 2B A schematic plan view of the support structure MT, mask, and membrane assembly 15 located in two different positions is shown.

[0156] The support structure MT is movably mounted within region 24. Specifically, the support structure MT can be positioned along the scanning direction (as indicated by arrow 26) (e.g., in...). Figure 2A The first end position shown in the figure is the same as (as shown in the figure). Figure 2B (As shown) the movement between the second end positions.

[0157] Unless otherwise illustrated, the following Cartesian coordinate set will be used throughout this specification. The scanning direction is labeled as the y-direction. Directions also in the plane of the support structure MT and perpendicular to the scanning direction are referred to as non-scanning directions, and these directions are labeled as the x-direction. Directions perpendicular to the plane of the support structure MT are labeled as the z-direction.

[0158] The lithography apparatus LA can be considered to include a scanning module operable to move a support structure MT in the scanning direction between at least a first end position and a second end position. For example, the scanning module can be operable to move the support structure MT relative to a support frame (schematically indicated by region 24) in the scanning direction, the support structure MT being considered to be movably mounted to the support frame.

[0159] The mask and film assembly 15 can be considered to include a central portion 15a and a peripheral portion 15b surrounding the central portion 15a. The central portion 15a can be referred to as the image forming portion and can coincide with the patterned radiation beam B of the mask MA and a portion of the septum of the film 19. The peripheral portion 15b can coincide with the border portion of the film 19 and the frame of the film 19.

[0160] The movement of the support structure MT between a first position and a second position defines a first extended region 28 of the support structure MT, said extended first extended region being defined by all areas in which the central portion 15a of the mask and the film assembly 15 can be disposed. That is, the extended first extended region 28 of the support structure MT is defined by moving the central portion 15a of the mask and the film assembly 15 from (as in...) Figure 2A The first end position (as shown in) is moved to (as in) Figure 2B The area defined by the second end position (as shown in the figure).

[0161] The photolithography apparatus LA is provided with four masking blades that define the extent of the field on the irradiated substrate W, as now referenced. Figure 3A , Figure 3B and Figure 4 As described. When the irradiation system IL is mounted on the support structure MT, the irradiation system IL is operable to irradiate an area of ​​the pattern forming apparatus MA. This area may be referred to as a slit of the irradiation system IL and is at least partially defined by four masking blades, which define a generally rectangular area of ​​the pattern forming apparatus capable of receiving radiation. The extent of the generally rectangular area in a first direction, which may be referred to as the x-direction, is defined by a pair of x-masking blades 32, 34. The extent of the generally rectangular area in a second direction, which may be referred to as the y-direction, is defined by a pair of y-masking blades 36, 38.

[0162] Each of the shielding blades 32, 34, 36, and 38 is positioned close to, but slightly outside, the plane of the pattern forming apparatus on the support structure MT. The x-shielding blades 32 and 34 are positioned in the first plane 40, and the y-shielding blades 36 and 38 are positioned in the second plane 42.

[0163] Each of the shielding blades 32, 34, 36, and 38 defines one edge of a rectangular field region 44 in the plane of the pattern forming apparatus MA, which can receive radiation. In practice, the irradiation system IL can irradiate only a portion of the rectangular field region 44. (As in...) Figure 4 As shown, the irradiation system IL can be arranged to irradiate a curved slit region 46, which can (depending on the position of the y-shading blades 36, 38) coincide with a portion of a rectangular field region 44.

[0164] The curved slit region 46 may be partially defined by optics within the illumination system IL and / or the projection system PS. Additionally, the curved slit region 46 may be partially defined by a plurality of independently movable objects provided along one or two of the curved edges of the curved slit region 46. These independently movable objects may be referred to as connecting fingers. The plurality of independently movable objects may be provided at different x-positions and movable in the y-direction to control the superposition of each movable object with the radiation beam B generated by the illumination system IL. Controlling the y-position of the movable member can control the shape (or at least the intensity distribution) of one or two of the curved edges of the curved slit region 46. The movable member can be used to minimize variations in the radiation dose provided by the radiation beam B at different positions in the non-scanning direction (i.e., the x-direction). Furthermore, the curved slit region 46 may be partially defined by a physical aperture (e.g., the entrance aperture of the projection system PS).

[0165] Each of the shielding blades 32, 34, 36, and 38 can move independently between a retracted position and an inserted position, wherein in the retracted position, each of the shielding blades 32, 34, 36, and 38 is not positioned in the path of the radiation beam, and in the inserted position, each of the shielding blades 32, 34, 36, and 38 at least partially blocks the radiation beam projected by the irradiation system IL onto the pattern forming apparatus MA. By moving the shielding blades 32, 34, 36, and 38 into the path of the radiation beam, the radiation beam B can be truncated (in the x and / or y directions), thus limiting the range of the field region 44 receiving the radiation beam B.

[0166] The x-direction corresponds to the non-scanning direction of the lithography apparatus LA, and the y-direction corresponds to the scanning direction of the lithography apparatus LA. The patterning apparatus MA is movable in the y-direction through the field region 44 (as indicated again by arrow 26) to expose a larger area of ​​the patterning apparatus MA in a single dynamic scan exposure.

[0167] During dynamic exposure of the target area of ​​substrate W, the target area moves through the exposure area in the plane of substrate W, which is the portion of the exposure area 44 of the patterning apparatus MA of substrate W imaged onto it by the projection system PS. As the target area of ​​substrate W moves into the exposure area, the first shielding blades 36, 38 move such that only the target area receives radiation (i.e., no part of the substrate outside the target area is exposed). At the start of the scan exposure, one of the y-shielding blades 36, 38 is positioned in the path of the radiation beam B as a baffle, ensuring that no part of substrate W receives radiation. At the end of the scan exposure, the other y-shielding blade 36, 38 is positioned in the path of the radiation beam B as a baffle, ensuring that no part of substrate W receives radiation. During the middle portion of the scan exposure, when there is no overlap between the exposure area 44 (which receives radiation B) and any of the adjacent target areas of substrate W, both y-shielding blades 36, 38 are positioned in a retracted position.

[0168] The rays of radiation beam B are shown adjacent to each of the shielding blades 32, 34, 36, and 38. It will be understood that each point in the slit region 46 is irradiated with radiation from some angle. For example, each point in the slit region 46 may receive a radiation cone. The rays of radiation beam B, shown adjacent to each of the shielding blades 32, 34, 36, and 38, indicate the average direction of the radiation received by the pattern forming apparatus MA. The rays of radiation beam B, shown adjacent to each of the shielding blades 32, 34, 36, and 38, may be referred to as the main rays. Figure 3A and Figure 3B As can be seen, in this embodiment, when projected onto the xz plane, the main ray of radiation is usually incident directly onto the pattern forming apparatus MA; however, when projected onto the yz plane, the main ray of radiation is usually incident onto the pattern forming apparatus MA at an angle of 48°.

[0169] The lithography apparatus LA may also include a gas nozzle 50, which may be arranged adjacent to the support structure MT to guide the airflow 52. Specifically, the airflow 52 provided by the gas nozzle 50 adjacent to the support structure MT is generally parallel to the surface of the pattern forming apparatus MA and may be referred to as crossflow. The gas nozzle 50 may generally be arranged in the same plane (first plane 40) as the x-masking vanes 32, 34. The gas nozzle may be oriented in the scanning direction such that the airflow 52 is generally parallel to the scanning direction and flows between the x-masking vanes 32, 34. The gas nozzle 50 can be considered as part of a gas supply module operable to provide airflow adjacent to the support structure MT.

[0170] The gas nozzle 50 can form a hydrogen source capable of supplying a portion of the hydrogen near the surface membrane 19 of the surface membrane and mask assembly when the surface membrane and mask assembly 15 is supported by the support structure MT.

[0171] Figure 4 The plan view of the y-shading blades 36 and 38 in the second plane 42 is shown, as in the positive z-direction (i.e., in... Figure 3B (Observed from the top). The positions of the x-shaped shielding blades 32 and 34 and the gas nozzle (which is positioned in the first plane 40) are shown by dotted lines. Figure 4 In this configuration, four shielding blades 32, 34, 36, and 38 are arranged to define a generally rectangular field region 44, within which a slit region 46 is disposed. This can be a typical configuration of the four shielding blades 32, 34, 36, and 38 during exposure of the central portion of a target region (e.g., a die on a substrate W). As explained above, each of the x-shielding blades 32 and 34 is operable to move in the x-direction, and each of the y-shielding blades 36 and 38 is operable to move in the y-direction to control the size of the field region 44. The y-shielding blades 36 and 38 are configured such that they can be actuated from the same side of the field region 44. To achieve this, the y-shielding blades 36 and 38 are shaped such that (however, the y-shielding blades 36 and 38 are located in substantially the same plane 42), each of the y-shielding blades 36 and 38 is provided with a slit along the same direction ( Figure 4 One or more support sections extending in the negative y direction.

[0172] The shielding blades 32, 34, 36, 38 and the gas nozzle 50 can be mounted on a common shielding blade assembly support (not shown). It will be understood that the shielding blades 32, 34, 36, 38 can be movably mounted on such a support such that the shielding blades 32, 34, 36, 38 can move relative to the support. The gas nozzle can be statically mounted on such a support.

[0173] In some embodiments, the lithography apparatus LA may be provided with a surface film 19 formed of CNTs.

[0174] The interaction between hydrogen ions and carbon materials is quantitatively described in the following two published papers, the contents of which are hereby incorporated by reference: (1) J. Roth, C. García-Rosales, “Analytic description of the chemicalerosion of graphite by hydrogen ions,” Nucl. Fusion, 1996, 36 / 12, 1647-1659; and (2) J. Roth, C. García-Rosales, “Corrigendum - Analytic description of the chemical erosion of graphite by hydrogen ions,” Nucl. Fusion, 1997, 37, 897. This quantitative description of the interaction between hydrogen ions and carbon materials can be referred to as the Roth-García-Rosales (RGR) model. The RGR model can be used to predict the etching yield as a function of temperature for carbon materials at typical hydrogen ion energies (e.g., ion energies ranging from 1 eV to 30 eV) encountered within a lithography apparatus. In an EUV lithography apparatus, the typical hydrogen ion flux incident on the surface film can be approximately 1.10... 19 m -2 · s -1 In EUV lithography equipment, the typical hydrogen ion flux incident on the surface film can be on multiple orders of magnitude, such as 1.10. 19 m -2 · s -1 (For example, from 10) 18 m -2 · s -1 Up to 10 20 m -2 · s -1 ).

[0175] Figure 5 The figures show the values ​​for four different ion energies: 5 eV, 10 eV, 20 eV, and 30 eV, for 1.5 × 10⁻⁶ eV. 19 m -2 · s -1 The hydrogen ion flux, the expected etching rate of carbon hydrogen etching as a function of temperature. Figure 5 It also shows the functional relationship between sp3 carbon concentration and temperature. From Figure 5As can be seen, for these typical environmental conditions in a lithography apparatus (LA), the hydrogen etching rate of the surface film formed solely by CNTs is expected to decrease to a negligible level at temperatures around 1050 K. However, those skilled in the art will appreciate that different minimum temperatures can be desired under different conditions.

[0176] In some embodiments, the minimum temperature is the temperature above which the hydrogen etch rate of the surface film 19 decreases to a level that can be ignored. In some embodiments, the minimum temperature may be 1000 K or above. As explained above, this can be advantageous for surface films formed solely of CNTs, wherein the hydrogen ion flux incident on the surface film may be approximately 1.10 19 m -2 · s -1 The hydrogen ion energy is approximately 1 eV to 30 eV. More preferably, the minimum temperature can be 1050 K or higher. In some embodiments, the minimum temperature can be 1100 K or higher.

[0177] The hydrogen etching rate decreases to a negligible level at high temperatures, which can be controlled by the transformation of sp3 carbon to sp2 carbon at a given temperature (see [reference]). Figure 5 Furthermore, a similar process occurs when forming sp2 carbon structures (such as graphene or CNTs), where the temperature of carbon is raised to convert the carbon into sp2 carbon, and the sp2 carbon structure is formed from said sp2 carbon. Such processes for growing graphene include, for example, chemical vapor deposition (CVD) and plasma-enhanced chemical vapor deposition (PE-CVD). Moreover, it is known that the growth of graphene from sp3 carbon sources can be initiated at temperatures as low as 300°C (573 K) in the presence of a single-atom catalyst. That is, the conversion of sp3 carbon to sp2 carbon can begin at this temperature in the presence of a single-atom catalyst. Lowering the etch-free operating temperature range of the film 19 is beneficial because it reduces the thermal load on the environment of the film 19. This also means that the heating system 20 must supply less heat to the film 19, which makes it easier for the system to provide this heat.

[0178] It has been found that once the film 19 has been heated to a level exceeding a threshold (at which hydrogen etching becomes negligible), there is a time lag before the etching rate increases from the negligible level once the heating is removed. It has also been found that after the time period at which the temperature at which hydrogen etching becomes negligible is reached, the hydrogen etching rate changes over time once the heating is removed, typically as follows: Figure 6 As shown in the qualitative analysis.

[0179] It is believed that heating to a sufficient temperature causes hydrogen to desorb from the surface film 19, reducing the hydrogen etching rate to a negligible level. Furthermore, it is believed that there is a time lag Δt in the increase in etching rate after heat removal, because the surface of the surface film 19 takes a non-zero time to be replenished with hydrogen after heating. This hydrogen replenishment rate can be proportional to the hydrogen radical flux to the septum of the surface film 19 within the lithography apparatus LA. As time increases from the time since heat removal, the etching rate eventually rises to the typical value for the surface film 19 at room temperature.

[0180] Some embodiments of this disclosure relate to a novel photolithography method 100, such as... Figure 7 As shown schematically. Figure 8 This is a schematic plan view of the mask and the film assembly 15 that can be used in photolithography method 100. Now refer to... Figure 7 and Figure 8 Let's discuss the novel photolithography method 100. It will be understood that the above references can be used. Figure 1 to Figure 4 The lithography apparatus LA of the described type is used to perform the novel lithography method 100, and the features of such lithography apparatus LA associated with the novel lithography method 100 will have the same characteristics as described above. Figure 1 to Figure 4 The same reference numerals are used in the description of the figures.

[0181] The photolithography method 100 includes a step 102 of forming an image of a mask multiple times on a substrate. Each such image forming process includes: irradiating a first portion 60 of the mask and the surface film assembly 15 with a radiation beam B; and collecting the radiation scattered by the mask MA and projecting the radiation onto a target area of ​​the substrate W using a projection optics PS.

[0182] The photolithography method 100 further includes a step 104 of periodically irradiating a second portion 62 of the mask and the surface coating assembly 15 using a radiation beam B. The second portion 62 of the mask and the surface coating assembly 15 at least partially surrounds the first portion 60. Figure 8 As shown, in at least some embodiments, the second portion 62 of the mask and the film assembly 15 substantially surrounds the first portion 60.

[0183] The first part 60 of the mask and the film assembly 15 can correspond to Figure 2A and Figure 2B The central portion 15a is shown and described above. Similarly, the second portion 62 can correspond to... Figure 2A and Figure 2B At least a portion of the peripheral portion 15b shown and as described above. Figure 8 As shown, in at least some embodiments, the mask and film assembly 15 may further include a third portion 64 surrounding the second portion 62. For such embodiments, in Figure 2A andFigure 2B The peripheral portion 15b shown and described above can be equivalent to a combination of the second portion 62 and the third portion 64. The third portion 64 can, for example, coincide with the border portion of the film 19 and the frame of the film 19.

[0184] As is being discussed now, Figure 7 The photolithography method 100 shown schematically is advantageous.

[0185] As mentioned above, any contaminants on the mask MA will typically alter the image formed on the substrate W, leading to printing errors. To avoid particle contamination of the mask MA, a thin diaphragm known as a surface layer 19 is used to protect the mask MA. The surface layer 19 is positioned in front of the mask MA and prevents particles from falling onto it. The surface layer 19 is configured such that it will not be clearly imaged onto the substrate W (e.g., a wafer coated with resist), and therefore particles on the surface layer 19 are less likely to interfere with the imaging process compared to particles on the mask MA. A particularly promising material for use as a diaphragm in EUV lithography equipment is carbon nanotube (CNT) fabric, which can provide very high EUV transmittance (greater than 98%) and very good mechanical stability. However, low-pressure hydrogen is typically present within the lithography equipment LA, which forms hydrogen plasma in the presence of EUV radiation (during exposure). It has been found that hydrogen ions and hydrogen radicals from hydrogen plasma can etch the surface film 19 formed by CNTs, thereby limiting the possible lifespan of the surface film 19 and hindering the commercial implementation of CNT surface films.

[0186] It has been found that the etching of carbon by hydrogen ions and free radicals is temperature-dependent. Specifically, it has been found that: (a) the carbon etching rate is non-zero at lower temperatures; and (b) the carbon etching rate decreases to a negligible level at a threshold temperature, and remains negligible above this threshold temperature. It has also been found that once the film 19 has been heated above the threshold level (where hydrogen etching becomes negligible), there is a time lag before the etching rate increases from a negligible level once the heating is removed.

[0187] The first portion 60 of the mask and film assembly 15 is the portion irradiated by (EUV) radiation B to form an image of the mask MA on the substrate W. Therefore, the first portion 60 of the mask and film assembly 15 may include the image-forming portion of the mask MA and the corresponding portion of the film 19. During each image formation process 102, the first portion 60 of the mask and film assembly 15 is exposed to EUV radiation B. This results in heating of the first portion 60 of the mask and film assembly 15 (for a lithography scanner LA, each portion or segment of the first portion 60 of the mask and film assembly 15 will be periodically heated, with the periodicity given by the rate at which the image is formed, i.e., once per die). As those skilled in the art will understand, within the lithography apparatus LA, hydrogen plasma is formed by EUV radiation B (for exposing the substrate W). Therefore, hydrogen plasma is formed near the first portion 60 of the mask and film assembly 15, which is exposed to EUV radiation and heated by this EUV radiation B. It will also be understood that the plasma can extend into the surrounding area that is not directly heated by EUV radiation B. As a result, the inventors have found that the coating 19 tends to fail in the region 62 surrounding the central portion 60 (which corresponds to the image forming portion).

[0188] Figure 9 A graph showing the function relationship between EUV transmittance of the CNT film and the non-scanning position (x position) is presented. Figure 9 The graph shown represents the change in resist height on a wafer exposed to EUV radiation via a surface coating, as a function of the non-scanning position (x-position). The change in resist height on the wafer is proportional to the change in EUV transmittance of the surface coating. Larger negative changes in resist height correspond to larger increases in EUV transmittance. Figure 9 The positions of the x-shading blades 32 and 34 are also shown (see [reference]). Figure 3A and Figure 3B ). Figure 9 The portion of the graph shown between the two lines corresponding to the positions of the x-shielding blades 32 and 34 represents the first portion 60 of the mask and coating assembly 15, which corresponds to the image forming portion of the mask MA. It can be seen that the EUV transmittance of the coating increases sharply only in the region outside the two lines corresponding to the positions of the x-shielding blades 32 and 34. This corresponds to a region that is not directly heated by the EUV radiation beam B but into which hydrogen ions and free radicals from the plasma can freely diffuse. This region, which may have a size of approximately 50 μm or 100 μm, is adjacent to the first portion 60 of the mask and coating assembly 15 and corresponds to the second portion 62 of the mask and coating assembly 15.

[0189] Advantageously, hydrogen etching of the second portion 62 of the mask and the film assembly 15 (which at least partially surrounds the first portion 60) can be suppressed by periodically irradiating the mask and the film assembly 15 with radiation beam B.

[0190] Figure 7 The photolithography method 100 shown includes the following two steps: (a) step 102, which involves forming an image of a mask multiple times on a substrate; and (b) step 104, which involves periodically irradiating the mask and a second portion 62 of the surface film assembly 15 using a radiation beam B. These steps can be performed in any order, as will be referred to below. Figure 10 to Figure 15 The subject of discussion.

[0191] In some embodiments, the irradiation 104 of the second portion 62 of the mask and the surface film assembly 15 using the radiation beam B can occur between exposures 102 of two target regions of the substrate W (i.e., between two image formation processes using the first portion 60 of the mask and the surface film assembly 15 with the radiation beam B). For example, the irradiation 104 of the second portion 62 of the mask and the surface film assembly 15 using the radiation beam B can occur between exposures of different target regions (or dies) of a single substrate W, or even between exposures of different substrates W. Reference will be made below. Figure 10 , Figure 11A and Figure 11B Examples of this type of arrangement are discussed.

[0192] Alternatively, in some embodiments, the irradiation 104 of the second portion 62 of the mask and the film assembly 15 using the radiation beam B can occur during the exposure of the target area of ​​the substrate W, and can be part of the exposure of the target area of ​​the substrate W (i.e., part of the image formation process using the first portion 60 of the mask and the film assembly 15 using the radiation beam B). Reference will be made below. Figure 12 to Figure 15 Examples of this type of arrangement are discussed.

[0193] In some embodiments, the mask and substantially the entire second portion 62 of the coating assembly 15 can be irradiated simultaneously using the radiation beam B. Reference will be made below. Figure 10 , Figure 11A and Figure 11B Examples of this type of arrangement are discussed.

[0194] Alternatively, in some embodiments, the second portion 62 of the mask and the coating assembly 15 may be irradiated with radiation beam B during multiple different exposures, each of which may expose a different portion or segment of the second portion 62 of the mask and the coating assembly 15 to radiation B. Reference will be made below. Figure 12 to Figure 15 Examples of this type of arrangement are discussed.

[0195] In some embodiments, step 104, which involves periodically irradiating the mask and the second portion 62 of the film assembly 15 using radiation beam B, is achieved by periodically irradiating an expanded exposure field, as now referred to. Figure 10 And as discussed in Figure 11.

[0196] The exposure field is the area of ​​the mask and the film assembly 15 exposed to radiation. It will be understood that the extent of the exposure field in the non-scanning direction (x-direction) can be defined by the extent of the radiation beam B in the non-scanning direction (which can be defined by a pair of shielding blades 32, 34). It will be understood that the extent of the exposure field in the scanning direction (y-direction) can be defined by both the extent of the radiation beam in the scanning direction (which can be defined by a pair of shielding blades 36, 38) and the range of the scanning motion.

[0197] Irradiation of such an expanded field can be part of the exposure of the target area of ​​the substrate W (i.e., part of the image forming process 102).

[0198] Alternatively, as now referenced Figure 10 As explained in Figure 11, the illumination of the extended field can occur between exposures of two target regions of the substrate W (i.e., between two image formation processes). For example, the illumination of the extended field can occur between exposures of different target regions (or dies) of a single substrate W, or even between exposures of different substrates W.

[0199] Figure 10 It shows Figure 7 The flowchart of the first embodiment 100a of the method 100 shown is as follows. Once the process begins, multiple (n) images are formed on a target area (e.g., a die) of a substrate W (e.g., a wafer coated with resist). After each image is formed on the target area, another image is formed if not all n images have been formed. After each image is formed on the target area, if all n images have been formed, an expanded exposure field is formed. It will be understood that the exposure of the expanded field is achieved through appropriate control of the masking blades 32, 34, 36, 38. For example, the masking blades 32, 34, 36, 38 may be positioned at a nominal location during the formation of each image on the target area of ​​the substrate W, while the masking blades 32, 34, 36, 38 may be positioned at different locations during the exposure of the expanded field.

[0200] Once the expanded field has been exposed to the EUV radiation beam B, the image counter can be reset, and additional n images can be exposed on the target area (e.g., die) of the substrate W (e.g., a wafer coated with resist). The process of forming n images on the target area of ​​the substrate W and then performing a single expanded exposure on the mask and the film assembly 15 can be repeated, for example, m times.

[0201] Figure 11A and Figure 11B yes Figure 10 A schematic illustration comparing method 100a with a standard photolithography process.

[0202] Figure 11A The illustration depicts a standard photolithography method in which a standard exposure field 70 is used n*m times to form an image on a target area on a substrate. A first portion 60 of the mask and film assembly 15 is exposed to EUV radiation and is therefore periodically heated to a temperature sufficient to minimize hydrogen etching of this first portion 60. Hydrogen plasma formed by EUV radiation near the first portion 60 of the mask and film assembly 15 also diffuses into the region adjacent to a second portion 62 of the mask and film assembly 15 surrounding the first portion 60. Since the second portion 62 of the mask and film assembly 15 is not directly heated by EUV radiation, this second portion 62 will undergo significant hydrogen etching, and the film will tend to fail in this second portion 62.

[0203] Figure 11B The diagram shows... Figure 10 The illustrated photolithography method 100a involves n exposures using a standard exposure field 70 to form an image on a target area on a substrate W, followed by one exposure using an expanded exposure field 72. This process of n+1 exposures is repeated m times. The first portion 60 of the mask and film assembly 15 is exposed to EUV radiation and is therefore periodically heated again to a temperature sufficient to minimize hydrogen etching of the first portion 60. During the n exposures using the standard exposure field, hydrogen plasma formed by EUV radiation near the first portion 60 of the mask and film assembly 15 also diffuses into the region adjacent to the second portion 62 of the mask and film assembly 15 surrounding the first portion 60. However, since the second portion 62 of the mask and film assembly 15 is directly heated by EUV radiation B during the exposures using the expanded exposure field, this second portion 62 of the mask and film assembly 15 will undergo significantly less hydrogen etching. In fact, if the time interval between two consecutive irradiations of the mask and the second portion 62 of the coating assembly 15 using the radiation beam B with the expanded exposure field 72 is small enough to prevent the surface of the coating from being replenished with hydrogen after the heating from the first such irradiation, the hydrogen etching of the second portion 62 can be minimized. Furthermore, it will be understood that the time required for replenishing the surface of the coating with hydrogen after the heating from the first irradiation using the expanded field 72 will depend on the conditions near the coating. In some embodiments, the time interval between two consecutive irradiations of the mask and the second portion 62 of the coating assembly can be approximately 100 ms or less.

[0204] During exposure using the expanded exposure field 72, the hydrogen plasma formed by EUV radiation B near the first portion 60 and second portion 62 of the mask and film assembly 15 will also diffuse into the region adjacent to the third portion 66 surrounding the second portion 62 of the mask and film assembly 15. Since the third portion 66 of the mask and film assembly 15 is not directly heated by EUV radiation B, this third portion 66 will undergo significant hydrogen etching, and the film may tend to fail in this third portion 66. However, the third portion 66 of the mask and film assembly 15 will only be exposed to this plasma for 1 / (n+1) of the time. This is in contrast to standard photolithography, in which the second portion 62 of the mask and film assembly 15 is exposed to plasma essentially for the entire time. Therefore, there will be a reduction in the amount of etching in the region experiencing the most etching, and a corresponding increase in the lifespan of the film (by a factor of n+1).

[0205] When the expanded exposure field 72 is periodically irradiated with radiation B, the radiation scattered from the mask and the surface film assembly 15 may not be projected onto the substrate W. This type of exposure can be called pseudo-exposure.

[0206] This pseudo-exposure can result in minimal adaptation to standard lithography methods. However, it also leads to a reduction in the productivity or throughput of the LA lithography equipment. In some embodiments, approximately one additional pseudo-exposure can be used per wafer (approximately ~100 full-field dies). This means that the throughput of the pseudo-exposure site is reduced by only ~1%. In some embodiments, a pseudo-exposure can be performed approximately once every ten dies, resulting in a throughput reduction of ~10%.

[0207] In some embodiments, the substrate W can be moved such that radiation scattered from the mask and surface coating assembly 15 does not incident on the substrate W. The spurious exposure can simply be selected outside the wafer W region and exposed after a row of target areas on the wafer W. Such exposure has been used in some lithography methods to ensure that edge dies are exposed to the same stray light as dies in the middle of the wafer W. Alternatively, in some embodiments, a baffle can be closed to prevent radiation scattered from the mask and surface coating assembly 15 from incident on the substrate W.

[0208] exist Figure 10 , Figure 11A and Figure 11BIn some embodiments of the illustrated embodiment 100a, this irradiation of the expanded field 72 may be part of the exposure of a target area of ​​the substrate W (i.e., part of the image formation process 102). Advantageously, this means that the exposure of the expanded field 72 will not negatively impact the productivity of the lithography equipment LA. Such embodiments can be achieved by making some changes to the mask and / or field distribution on the wafer W (see reference below). Figure 14 and Figure 15 (To be discussed further).

[0209] exist Figure 7 In some embodiments of the method 100 shown, step 104, which involves periodically irradiating the mask and the film assembly 15 with a radiation beam, is achieved by changing the exposure field. It will be understood that, typically, the range and / or location of the exposure field can vary. (Refer to above) Figure 10 to Figure 11B The described embodiment 100a is an example of such an embodiment in which the exposure field is changed. Referring now... Figure 12 to Figure 15 Other embodiments of this method of altering the exposure field are described below.

[0210] Figure 12 It shows Figure 7 The flowchart of the second embodiment 100b of the method 100 shown is as follows. Once the process begins, multiple images are formed on a target area (e.g., a die) of a substrate W (e.g., a wafer coated with resist). After each image is formed on the target area, the exposure field is changed (in range and / or location). It will be understood that the change of exposure field is achieved by appropriate control of the masking blades 32, 34, 36, 38.

[0211] For example, the masking blades 32, 34, 36, and 38 may be positioned at a first location during the formation of a first image on a target area of ​​the substrate W, and the same masking blades 32, 34, 36, and 38 may be positioned at a second location during the formation of a second image on the target area of ​​the substrate W, and so on. Typically, the position of at least one edge of the exposure field (defined by one of the masking blades 32, 34, and 36) used in at least some image forming processes is shifted by an offset relative to the position of at least one edge of the exposure field in a previous image forming process.

[0212] For example, the offset could be approximately 50 μm. At least one edge of the exposure field can be stepped with such an offset every n exposure cycles (e.g., each exposure cycle). In some embodiments, all edges of the exposure field can be stepped with such an offset (by having each of the masking blades 32, 34, 36, 38 stepped with such an offset). Method 100b can use, for example, approximately five different positions for each edge of the exposure field, and the position of each edge of the exposure field can be stepped or cycled through all (e.g., the five) different positions.

[0213] Figure 13 The graphs showing the EUV transmittance of the indicated CNT film as a function of the non-scanning position (x position) for the following methods are shown: (a) standard lithography method (solid line); (b) Example 100b of the novel method, wherein the shielding blades 32 and 34 are stepped in ten 2 mm increments (dashed line). Figure 13 The graph shown represents the relationship between the change in resist height on a wafer exposed to EUV radiation via a surface film and the non-scanning position (x-position) at the mask level. The change in resist height on the wafer is proportional to the change in EUV transmittance of the surface film. Larger negative changes in resist height correspond to larger increases in EUV transmittance. Figure 13 The approximate locations of the x-shading blades 32 and 34 are also shown (see [reference]). Figure 3A and Figure 3B As can be seen from the comparison of the curves for the standard photolithography method and the novel method in Example 100b, advantageously, due to the stepping of the x-shading blades 32, 34, there are no longer sharp peaks in the EUV transmittance of the surface film only in the region outside the x-shading blades 32, 34.

[0214] In alternative embodiments, the exposure field used for multiple image forming processes can be continuously varied. For example, the position of at least one edge of the exposure field (defined by the masking blades 32, 34, 36, 38) can be continuously varied. For example, the position of at least one edge of the exposure field (defined by the masking blades 32, 34, 36, 38) can oscillate at some positions around a nominal position. The amplitude of such oscillation can be approximately 100 μm. In some embodiments, all edges of the exposure field can be continuously varied (by oscillating the positions of all masking blades 32, 34, 36, 38).

[0215] although Figure 12 The illustrated exemplary embodiment 100b includes changing the exposure field after an image forming process; however, in alternative embodiments, the exposure field may be changed after a different number of image forming processes. Generally, the exposure field used for at least some image forming processes may differ from the exposure field used for previous image forming processes.

[0216] In some embodiments, in order to form an image on each target region of the substrate W adjacent to the edge of the substrate W, at least one of the masking blades 32, 34, 36, 38 corresponding to the edge of the exposure field adjacent to the edge of the substrate W can be positioned to expand the exposure field, as now referenced. Figure 14 and Figure 15 As described above, generally, four shielding blades 32, 34, 36, 38 can be used during exposure of each target region of substrate W to define the exposure field.

[0217] Figure 14 It shows Figure 7 The flowchart of the third embodiment 100c of the method 100 shown. Figure 15 It is a schematic plan view representing a substrate W comprising multiple (generally rectangular) target regions C or dies (generally circular). Figure 15 In the illustrated embodiment, the substrate W includes 110 target regions C. Target regions C adjacent to the edges of the substrate W may be referred to as edge target regions or edge dies. It will be understood that such edge target regions C do not have adjacent target regions C on all sides. Instead, on at least one side (adjacent to the edges of the substrate W), each edge target region C has no adjacent neighboring target region C. For example, the upper left target region C (numbered 110) has no adjacent target regions in either the positive y-direction or the negative x-direction. For such edge target regions C (or dies) on the substrate W, shielding blades 32, 34, 36, and 38 may be positioned to expand the exposure area, as now explained.

[0218] Once the third embodiment 100c of method 100 begins, multiple images are formed on a target area (e.g., a die) of the substrate W (e.g., a wafer coated with resist). If the next target area to be exposed is not an edge target area, a nominal exposure area can be used (e.g., the masking blades 32, 34, 36, 38 are in the nominal position). If the next target area to be exposed is an edge target area, an expanded exposure area can be used (e.g., at least one of the masking blades 32, 34, 36, 38 is in the open position). It will be understood that the exposure field can be altered by appropriate control of the masking blades 32, 34, 36, 38.

[0219] For example, for such edge target regions C (or dies) on substrate W, the shielding blades 32, 34, 36, 38 can be shifted by 1 mm or more relative to their nominal positions to expand the exposure area. Advantageously, this will result in the irradiation of a portion of the mask and coating assembly 15 adjacent to the first portion 60 of the mask and coating assembly 15 (and corresponding to a portion or segment of the second portion 62 of the mask and coating assembly 15) using radiation beam B. If the shielding blades 32, 34, 36, 38 are controlled in this manner for all such edge dies C, then a portion 62 of the mask and coating assembly 15 substantially surrounding the first portion 60 of the mask and coating assembly 15 can be irradiated using radiation B.

[0220] Forming multiple images of a mask MA on a substrate can include forming images of the mask MA on multiple target regions C of a substrate W. Each of the multiple target regions C can be approximately rectangular. The multiple target regions C can be arranged in a two-dimensional array.

[0221] In some embodiments, a standard zigzag scan pattern can be used to expose a two-dimensional array of target regions C, in which each row of target regions C (extending in the non-scanning direction) is sequentially exposed. Figure 15 The diagram illustrates a standard zigzag scanning pattern, where the exposure sequence of target regions C is indicated by a number on each target region. The scanning direction of the exposure of each target region C is indicated by a solid arrow, and the movement of the substrate W between exposures of two consecutive target regions C is indicated by a dashed line.

[0222] In each row, one target region C has no adjacent target region on one side, while another target region has no adjacent target region on the other side. For example, in the second row starting from the top, target region 99 has no adjacent target region on the left (negative x direction), and target region 106 has no adjacent target region on the right (negative y direction). Therefore, with this arrangement, portions of the mask and coating assembly 15 that are adjacent to the first portion 60 of the mask and coating assembly 15 but offset in the non-scanning direction (x direction) can be exposed to radiation during the exposure of each row.

[0223] Conversely, during exposure of the first half of substrate W, there are some target regions that do not have adjacent target regions on the first side in the scanning direction, but there are no target regions that do not have adjacent target regions on the other (second) side in the scanning direction. For example, in the first half of substrate W ( Figure 15During the exposure of the lower half of the substrate W, some target regions C have no adjacent target regions below (in the negative y direction), but no target regions have no adjacent target regions above (in the positive y direction). Similarly, during the exposure of the first half of the substrate, some target regions have no adjacent target regions on the second side in the scanning direction, but no target regions have no adjacent target regions on the first side in the scanning direction. For example, in the second half of the substrate W (… Figure 15 During the exposure of the upper half of the substrate W, there are some target regions C that have no adjacent target regions above (in the positive y direction), but there are no target regions that have no adjacent target regions below (in the negative y direction).

[0224] In some embodiments, an exposure pattern can be used to expose a two-dimensional array of target regions C, in which multiple rows of target regions C (extending in the non-scanning direction, i.e., the x-direction) are exposed in different orders to increase the exposure on the first or second side in the scanning direction (i.e., on the x-direction). Figure 15 The frequency of target regions (located above or below the target region) without adjacent target regions is increased. In some embodiments, forming an image of a mask MA multiple times on a substrate W may include: forming an image of a mask MA on a plurality of target regions C on the substrate W, the plurality of target regions C being arranged in a two-dimensional array, wherein the two-dimensional array of target regions C is exposed one row at a time, and wherein the rows are exposed out of order.

[0225] exist Figure 7 In some embodiments of the method 100 shown, at least one shielding blade 32, 34, 36, 38 may be used during each image formation process to shield adjacent target regions C of the substrate W from the radiation beam B. Preferably, four shielding blades 32, 34, 36, 38 may be used to define an exposure area and shield adjacent target regions C on all four sides of the exposure area C. The exposure field C may be defined by the exposure area, the scan length, and the positions of the four shielding blades 32, 34, 36, 38.

[0226] exist Figure 7 In some embodiments of the method 100 shown, at least one masking blade 32, 34, 36, 38 can be manipulated such that the perimeter of the exposure area is expanded over the extended region. For example, the perimeter of the exposure area can be expanded over an area with a size of approximately 100 μm.

[0227] exist Figure 7In some embodiments of the method 100 shown, each image formation process may include a scanning exposure in which the mask and the film assembly 15 are moved relative to the radiation beam B in a scanning direction (e.g., the y direction).

[0228] Generally, in Figure 7 In an embodiment of method 100 shown, the duration for which the second portion 62 of the mask and the film assembly 15 is periodically irradiated with radiation beam B can be sufficiently long to heat the second portion 62 of the film to a desired temperature (e.g., above a threshold temperature where hydrogen etching of the film can be negligible). In some embodiments, the desired temperature can be above 900 K. It will be understood that the time required to heat the film to the desired temperature will depend on the power of radiation beam B while it is heating the film.

[0229] exist Figure 7 In some embodiments of the method 100 shown, periodically irradiating the mask and the second portion 62 of the coating assembly 15 with the radiation beam B may include exposing the second portion 62 to EUV radiation to heat the coating to a temperature at which the hydrogen etching rate of the coating can be negligible. For example, periodically irradiating the mask and the second portion 62 of the coating assembly 15 with the radiation beam B may include exposing the second portion to EUV radiation to heat the coating to a temperature above 800 K, such as above 900 K.

[0230] Generally, the time interval between two consecutive irradiations of the mask and the second portion 62 of the coating assembly 15 using radiation beam B can be small enough to prevent the surface of the coating from being replenished with hydrogen after the heating from the first irradiation. Furthermore, it will be understood that the time required for the surface of the coating to be replenished with hydrogen after the heating from the first irradiation will depend on the conditions near the coating. In some embodiments, the time interval between two consecutive irradiations of the mask and the second portion of the coating assembly can be approximately 100 ms.

[0231] exist Figure 7 In some embodiments of the method 100 shown, step 104, in which the mask and the second portion 62 of the film assembly 15 are periodically irradiated with radiation beam B, causes the second portion 62 of the mask and the film assembly 15 to be irradiated once for each substrate W.

[0232] exist Figure 7 In some embodiments of the method 100 shown, step 104, in which the mask and the second portion 62 of the film assembly 15 are periodically irradiated with radiation beam B, causes the second portion 62 of the mask and the film assembly 15 to be irradiated once for each row of target regions C on the substrate W.

[0233] As described above, embodiments of this disclosure propose using the masking blades 32, 34, 36, and 38 in novel modes of operation. In some embodiments (particularly when an expanded exposure field is exposed as part of the formation of an image on a target area of ​​the substrate W), this novel functionality of the masking blades 32, 34, 36, and 38 can be combined with some changes to the mask layout and / or the film boundary, as now discussed.

[0234] Typically, a mask includes a central image-forming portion surrounded by a black boundary region. This black boundary region may have a reflectivity to EUV radiation ranging from 0.1% to 5%, for example, less than 1%. The black boundary region may have a size of approximately 1 mm to 5 mm, for example, approximately 2 mm to 3 mm. Around this black boundary, the mask may be provided with one or more alignment marks.

[0235] In embodiments where the expanded exposure field is exposed as part of the formation of an image on a target area of ​​substrate W, the expanded field, due to additional flash, particularly at the corners of the target area, may adversely affect critical dimensional uniformity (CDU). This effect will depend on the effectiveness of the mask's black boundary and the field layout used on the wafer (e.g., the proximity of two adjacent target areas C together).

[0236] When using extended exposure to recover the surface film, the available image area or region may be reduced. Since the extended exposure field is not used for every exposure (of the target region C of the substrate W), the additional area (relative to the nominal exposure field) must contain imaging information. In some embodiments, the mask may be configured with an extended black border to mitigate any loss of imaging performance caused by the extended exposure field.

[0237] For example, in some embodiments, the operation of the novel shielding blades 32, 34, 36, 38 may involve periodically using an expanded exposure field in which each of the shielding blades 32, 34, 36, 38 is moved outward by a distance of approximately ~800 μm relative to a single die / target region C. (See above reference...) Figure 10 , Figure 11A and Figure 11B This is explained to mean that the second portion 62 of the mask and the coating assembly 15 is exposed to EUV light, thereby preventing hydrogen etching of the second portion 62 from starting. The frequency of this expanded exposure area can be approximately ~1 per 50 dies / target areas C, which will result in a 50-fold increase in the coating's lifespan.

[0238] However, in some existing mask layouts, the black border of the mask is now wide enough to allow the masking blades 32, 34, 36, and 38 to move very far freely without causing imaging artifacts at the edges and corners of the target area C.

[0239] One way to achieve an expanded black border is to reduce the size of the available image-forming area. For example, the imaging field can be reduced by shifting all the edges of the image-forming area of ​​the mask inward by ~800 μm in both the x and y directions.

[0240] Another way to achieve an extended black boundary is to move the position of alignment marks on the mask. Alignment marks are typically positioned in a so-called quiet zone. A quiet zone is a region around the alignment mark where no other radiation scattering or reflection features are present that could interfere with the signal from the alignment mark. Specifically, no other radiation scattering or reflection features are positioned in the quiet zone to: (a) avoid cross-terms of the alignment mark signal; and (b) prevent any radiation leakage through the surrounding absorber material (typically, the alignment mark can be significantly smaller than the sensitive area of ​​the detector used for alignment measurements, making these measurements highly sensitive to stray radiation even when any stray radiation falls on the absorber area of ​​the detector). In some embodiments, to achieve an extended black boundary, the alignment mark can be moved from the quiet zone and into the dicing channel (the region corresponding to the gap between adjacent target regions C on the wafer W), which allows the black boundary to be extended into the quiet zone. Alternatively, in some embodiments, the dimensions of the film boundary and frame can be reduced, for example, by 1 mm, the dimensions of the black boundary can be increased by 1 mm, and the alignment mark can be moved outward by 1 mm. In such embodiments, the alignment mark can terminate on a lower quality portion of the mask. However, this is not expected to cause any significant problems.

[0241] If a reduction in the available image area is unacceptable or undesirable, an alternative could be to allow an expanded exposure field to overlap with the coating boundary. Generally, exposure at the coating boundary is avoided because all EUV light will be absorbed, resulting in a thermal boundary; however, the thermal load from the periodic use of an expanded exposure field at the coating boundary may be acceptable.

[0242] Some embodiments of this disclosure relate to Figure 1 The lithography equipment LA of the type shown. The lithography equipment LA may include the above-referenced... Figure 1 to Figure 4 The described features. In particular, the novel lithography apparatus LA according to embodiments of this disclosure includes: a controller CN operable to control the irradiation system IL (see...). Figure 1The substrate includes a support structure MT, a substrate stage WT, and a projection system PS, for the following purposes: (a) to form multiple images of a mask MA supported by the support structure MT on the substrate W, each such image formation process comprising: irradiating a first portion 60 of the mask and the surface film assembly 15 with a radiation beam B; and projecting the radiation scattered by the mask MA onto a target region C on the substrate W using a projection optics PS; and (b) to periodically irradiate a second portion 62 of the mask and the surface film assembly 15 with a radiation beam B, the second portion 62 of the mask and the surface film assembly 15 at least partially surrounding the first portion 60.

[0243] Because this lithography equipment LA allows the implementation of the novel lithography methods 100, 100a, 100b, and 100c discussed above, this lithography equipment LA is advantageous.

[0244] As discussed above, the surface layer 19 positioned in front of the mask MA prevents particles from falling onto the mask MA, which can improve optical performance (by reducing printing errors). A particularly promising material for use as a diaphragm in EUV lithography equipment is a fabric of carbon nanotubes (CNTs); however, CNT surface layers are susceptible to hydrogen etching. It has been found that etching of carbon by hydrogen ions and free radicals decreases to a negligible level at a threshold temperature, and remains negligible above this threshold temperature. It has also been found that once the surface layer 19 has been heated above the threshold level (where hydrogen etching becomes negligible), there is a time lag before the etching rate increases from a negligible level once the heating is removed.

[0245] The first portion 60 of the mask and film assembly 15 is the portion irradiated by (EUV) radiation to form an image of the mask MA on the substrate W. Therefore, the first portion 60 of the mask and film assembly 15 may include the image-forming portion of the mask MA and the corresponding portion of the film 19. During each image-forming process, the first portion 60 of the mask and film assembly 15 is exposed to EUV radiation. This results in heating of the first portion 60 of the mask and film assembly 15 (for a lithography scanner LA, each portion of the first portion 60 of the mask and film assembly 15 will be periodically heated, given by the rate at which the image is formed, i.e., once per die). As those skilled in the art will understand, within the lithography apparatus LA, hydrogen plasma is formed by EUV radiation (for exposing the substrate W). Therefore, hydrogen plasma forms near the first portion 60 of the mask and film assembly 15, which is exposed to and heated by EUV radiation. It will also be learned that the plasma can extend into the surrounding area that is not directly heated by EUV radiation. As a result, the inventors have found that the coating tends to fail in the area surrounding the central portion (which corresponds to the image-forming portion).

[0246] Advantageously, hydrogen etching of the second portion 62 of the mask and the film assembly 15 (which at least partially surrounds the first portion 60) can be suppressed by periodically irradiating the mask and the film assembly 15 with radiation beam B.

[0247] The controller CN is capable of operating to implement the novel photolithography methods 100, 100a, 100b, and 100c discussed above.

[0248] The lithography apparatus LA may also include a scanning mechanism operable to move a support structure MT relative to a radiation beam B modulated by an illumination system IL in the scanning direction (y-direction). The scanning mechanism is also operable to move a substrate stage WT relative to a projection system PS, such that the image of a mask MA formed by the projection system PS is substantially stationary relative to the substrate W. This can be described as the synchronous movement of the support structure MT and the substrate stage WT. The movement (direction and speed) of the substrate stage WT relative to the support structure MT will typically depend on the image inversion and magnification characteristics of the projection system PS.

[0249] The controller CN is capable of operating to control the scanning mechanism.

[0250] As described above, the lithography apparatus LA may include: a first pair of masking blades 36, 38, the first pair of masking blades 36, 38 being arranged to define the exposure area in a first direction (y direction); and a second pair of masking blades 32, 34, the second pair of masking blades 32, 34 being arranged to define the exposure area in a second direction (x direction).

[0251] The first pair of masking blades 36, 38 and the second pair of masking blades 32, 34 can be movable to change the extent of the exposure area. The controller CN is operable to control the position of each or each pair of masking blades 36, 38 and 32, 34. In use, both pairs of masking blades 36, 38, 32, 34 can be used to define the exposure area and mask adjacent target areas C on all four sides of that exposure area.

[0252] In some embodiments, in order to form an image of a mask MA supported by a support structure MT on a target region C of a substrate W, the controller CN is operable to: control the scanning mechanism to move the mask MA supported by the support structure MT through the exposure area; and control the position of the first pair of shielding blades 36, 38 to shield the adjacent target region C of the substrate W from being irradiated by the radiation beam.

[0253] In some embodiments, in order to irradiate the mask and the second portion 62 of the film assembly 15 with the radiation beam B, the controller CN can be operated to control the first pair of shielding blades 36, 38 and / or the second pair of shielding blades 32, 34 to irradiate an expanded exposure field.

[0254] The exposure field is the area of ​​the mask and the film assembly 15 exposed to radiation. It will be understood that the extent of the exposure field in the non-scanning direction (x-direction) can be defined by the extent of the radiation beam in the non-scanning direction (which can be defined by a pair of shielding blades 32, 34). It will be understood that the extent of the exposure field in the scanning direction (y-direction) can be defined by both the extent of the radiation beam in the scanning direction (which can be defined by a pair of shielding blades 36, 38) and the range of the scanning motion.

[0255] Irradiation of this expanded field can be part of the exposure of a target region of the substrate W (i.e., part of the image formation process). Alternatively, irradiation of the expanded field can occur between exposures of two target regions C of the substrate W (i.e., between two image formation processes). For example, irradiation of the expanded field can occur between exposures of different target regions C (or dies) of a single substrate W, or even between exposures of different substrates W.

[0256] In some embodiments, in order to irradiate the mask and the second portion 62 of the film assembly 15 with the radiation beam B, the controller CN is operable to control the first pair of shielding blades 36, 38 and / or the second pair of shielding blades 32, 34 to change the exposure field. It will be understood that the range and / or position of the exposure field can be changed.

[0257] In some embodiments, the controller CN is operable to control the first pair of shielding blades 36, 38 and / or the second pair of shielding blades 32, 34 such that the exposure field used for at least some image forming processes is different from the exposure field used for previous image forming processes.

[0258] In some embodiments, the controller CN is operable to control the first pair of masking blades 36, 38 and / or the second pair of masking blades 32, 34 such that at least one edge of the exposure field for each of at least some image forming processes is shifted by an offset. For example, this offset may be approximately 50 μm. At least one edge of the exposure field may be stepped with such an offset every n exposure processes (e.g., each exposure process). In some embodiments, all edges of the exposure field may be stepped with such an offset. The method implemented by the controller CN may use, for example, approximately five different positions for each edge of the exposure field, and may cause the position of each edge of the exposure field to be stepped or cycled through all (e.g., the five) different positions.

[0259] In some embodiments, the controller CN is operable to control the first pair of masking blades 36, 38 and / or the second pair of masking blades 32, 34, such that the exposure field for multiple image forming processes is continuously varied. For example, the position of at least one edge of the exposure field can be continuously varied. For example, the position of at least one edge of the exposure field can oscillate at some positions around a nominal position. The amplitude of such oscillation can be approximately 100 μm. In some embodiments, all edges of the exposure field can be continuously varied.

[0260] In some embodiments, in order to irradiate the mask and the second portion 62 of the film assembly 15 with the radiation beam B, the controller CN is operable to control the first pair of shielding blades 36, 38 and / or the second pair of shielding blades 32, 34 such that the perimeter of the exposure area expands over the extended region. For example, the perimeter of the exposure area may expand over an area having a size of approximately 100 μm.

[0261] In some embodiments, in order to irradiate the second portion 62 of the mask and the film assembly 15 with the radiation beam B, the controller CN is operable to control the first pair of shielding blades 36, 38 and / or the second pair of shielding blades 32, 34 such that when an image of the mask MA supported by the support structure MT is formed on a target region C adjacent to the edge of the substrate W, at least one of the shielding blades 32, 34, 36, 38 corresponding to the edge of the exposure field adjacent to the edge of the substrate W can be positioned to expand the exposure field.

[0262] The target region C adjacent to the edge of the substrate W can be referred to as the edge target region C or the edge die. It will be understood that such an edge target region C does not have adjacent target regions C on all sides. Instead, on at least one side (adjacent to the edge of the substrate W), each edge target region C has no adjacent neighboring target region. For such edge target regions C (or dies) on the substrate W, shielding blades 32, 34, 36, 38 can be positioned to expand the exposure area. For example, for such edge target regions C (or dies) on the substrate W, shielding blades 32, 34, 36, 38 can be shifted by 1 mm or more relative to their nominal positions to expand the exposure area. Advantageously, this will result in the irradiation of a portion 62 of the mask and coating assembly 15 adjacent to the first portion 60 of the mask and coating assembly 15 using the radiation beam B. If the shielding blades 32, 34, 36, and 38 are controlled in this manner for all such edge dies, then radiation B can be used to irradiate a portion 62 of the mask and the film assembly 15 that substantially surrounds the first portion 60 of the mask and the film assembly 15.

[0263] Forming multiple images of a mask MA on a substrate can include forming images of the mask MA on multiple target regions C of a substrate W. Each of the multiple target regions C can be approximately rectangular. The multiple target regions C can be arranged in a two-dimensional array.

[0264] Generally, the duration for which the mask and the second portion 62 of the film assembly 15 are periodically irradiated by the radiation beam B can be sufficiently long to heat the second portion 62 of the film to a desired temperature (e.g., above a threshold temperature where hydrogen etching of the film can be negligible). In some embodiments, the desired temperature can be above 900 K. It will be understood that the time required to heat the film to the desired temperature will depend on the power of the radiation beam while it is heating the film.

[0265] In some embodiments, when the mask and the second portion 62 of the film assembly 15 are irradiated with radiation beam B, the controller CN is operable to heat the film to a temperature at which the hydrogen etching rate of the film is negligible. For example, the controller CN is operable to heat the film to a temperature above 800 K, such as above 900 K.

[0266] Some embodiments of this disclosure relate to novel surface films for use in photolithography equipment, which have been adapted to undergo less plasma etching during use than existing surface films; and relate to including such novel surface films in... Figure 1 The type of lithography equipment LA shown in the figure is now referenced. Figure 16 to Figure 19 The subject of discussion.

[0267] Figure 16 A portion of the mask and membrane assembly is shown in cross-section. A portion of the mask MA, the membrane frame 17, and the membrane septum 19 are all present. Figure 16 The image is shown in the diagram. A portion of the support 74 that facilitates the connection between the faceplate (frame 17 and diaphragm 19) and the mask MA is also shown. The support 74 may include an intermediate fixing member (referred to as a stud) that is secured to the pattern forming apparatus (mask). The intermediate fixing member (stud) on the pattern forming apparatus (mask) can engage (e.g., releasably engage) with an attachment member of the faceplate frame 17. This is all schematically represented as the support 74. One of the x-shading blades 32 is also shown.

[0268] The coating can receive a portion of EUV radiation during use. Figure 16 The portion 76 of the film that can receive EUV radiation can be roughly equivalent to the first portion 60 of the mask and film assembly 15 discussed above (the portion irradiated by (EUV) radiation B to form an image of the mask MA on the substrate W). That is, the portion 76 of the film can include the portion of the film 19 corresponding to the image-forming portion of the mask MA.

[0269] The portion of the membrane that does not receive EUV radiation but does receive hydrogen plasma during use... Figure 16 The middle part is indicated by arrow 78. This portion 78 of the film can be roughly equivalent to the portion surrounding the central portion 60 of region 62 of the mask and film assembly 15, and as discussed above. The location of the peak etch intensity attributed to hydrogen plasma is in Figure 16 The middle is indicated by arrow 80.

[0270] In use, the diaphragm 19 will receive a heat load from EUV radiation (e.g., EUV radiation) used by the lithography equipment, and potentially also from one or more heaters. However, the frame 17 will remain at a temperature significantly lower than that of the diaphragm 19 due to its significantly increased heat capacity and thermal inertia. The area of ​​the diaphragm 19 in contact with the frame 17 has a reduced temperature due to the presence of the frame 17, and there is good thermal contact between the frame 17 and the diaphragm 19 (the frame 17 functions as a heat sink). However, it can be seen that there is an overlap between the diaphragm 19 and the frame 17 in the portion 78 of the diaphragm that does not receive EUV radiation but does receive hydrogen plasma.

[0271] Because the frame 17 is used as a heat sink, rapid heating of this portion of the diaphragm 19, which overlaps with both the frame 17 and the hydrogen plasma region, will not effectively raise the temperature of this portion of the diaphragm 19 above 600°C.

[0272] Some embodiments of this disclosure relate to novel surface films for use in lithography apparatus LA, which have been adapted to move the contact portion between the frame 17 and the diaphragm 19 outward along at least one edge of the diaphragm 19, as now referenced. Figure 17A to Figure 17E The subject of discussion.

[0273] Figure 17A This is a schematic cross-section of a portion of a known membrane 82. The known membrane 82 includes: a frame 17; and a diaphragm 19 surrounded and supported by the frame 17. The diaphragm 19 is generally flat and defines the plane of the membrane 82. The frame 17 is generally rectangular in cross-section, having a thickness 84 generally perpendicular to the plane of the membrane and a width 86 generally parallel to the plane of the membrane.

[0274] Figure 17B to Figure 17D This is a schematic cross-section of a portion of three novel faceplates 88, 89, and 90. The novel faceplates 88, 89, and 90 also include: a frame 17; and a diaphragm 19 surrounded and supported by the frame 17. The diaphragm 19 is generally flat and defines the planes of the faceplates 88, 89, and 90. The frame 17 has a thickness 84 generally perpendicular to the plane of the faceplate and a width 86 generally parallel to the plane of the faceplate.

[0275] Figure 17B to Figure 17DThe frame 17 of each of the novel membranes 88, 89, 90 shown can be considered to include an outer portion 17a and an inner portion 17b. The outer portion 17a of the frame 17 contacts the diaphragm 19, and along at least one edge of the diaphragm 19, the inner portion 17b of the frame 17 does not contact the diaphragm 19. In particular, along at least one edge of the diaphragm 19, the inner portion 17b of the frame 17 has a reduced thickness 84 relative to the outer portion 17a of the frame 17, such that the inner portion 17b of the frame 17 does not contact the diaphragm 19.

[0276] In use, the diaphragm 19 will receive radiation (e.g., EUV radiation) used by the lithography equipment and heat loads from one or more heaters, while the frame 17 will remain at a lower temperature. Due to the presence of the frame 17 (which has greater thermal inertia than the diaphragm 19 due to its larger size), the area of ​​the diaphragm 19 in contact with the frame 17 has a reduced temperature. Figure 17B to Figure 17D The novel membranes 88, 89, and 90 shown allow the contact portion between the frame 17 and the diaphragm 19 to move outward along at least one edge of the diaphragm 19 without reducing the width 86 of the frame 17 (i.e., the dimension of the frame 17 that is substantially parallel to the plane of the membrane). Figure 17B to Figure 17D The novel outer films 88, 89, and 90 shown are advantageous. This allows the frame 17 to maintain a similar level of rigidity (e.g., as shown in the diagram). Figure 17A The known membrane 82 shown is used, while the contact portion between the frame 17 and the diaphragm 19 is moved outward. Furthermore, advantageously, by moving the portion of the diaphragm 19 in contact with the frame 17 (and the portion of the diaphragm 19 in contact with the frame 17 at a lower temperature during use than the rest of the diaphragm 19) outward, the diaphragm 19 is exposed to less or even no high-intensity EUV-induced hydrogen plasma.

[0277] Figure 17B to Figure 17D The novel films 88, 89, and 90 shown, or each of the novel films 88, 89, and 90, define a recess 92 between the inner portion 17b of the frame 17 (having a reduced thickness 84) and the diaphragm 19. It will be understood that the recess 92 can have various different shapes. For example, the recess 92 can have a substantially uniform thickness (e.g., Figure 17C and Figure 17D (As shown). Figure 17C The illustrated embodiment also includes rounded or rounded portions between the inner portion 17a and the outer portion 17b of the frame 17. This arrangement can reduce stress concentration in the frame 17.

[0278] Alternatively, the recess 92 formed between the inner portion 17b (with a reduced thickness 84) of the frame 17 and the diaphragm 19 may have a thickness 84 that varies from the inner edge of the frame 17 to the outer portion 17b of the frame 17 (e.g., Figure 17B (As shown).

[0279] The width 86 of the inner portion 17b of the frame 17 (with a reduced thickness 84) can be selected such that the portion of the diaphragm 19 in contact with the frame 17 (and the portion of the diaphragm 19 in contact with the frame 17 is at a lower temperature in use than the rest of the diaphragm 19) is not adjacent to high-intensity EUV-induced hydrogen plasma (i.e., not superimposed on the region 78 of the surface membrane that does not receive EUV radiation but does receive hydrogen plasma and the frame 17; see also). Figure 16 ).

[0280] The width 86 of the inner portion 17b of the frame 17, which has a reduced thickness, can be greater than 2 mm. In some embodiments, the width 86 of the inner portion 17b of the frame 17 can be greater than 2.2 mm. In some embodiments, the width 86 of the inner portion 17b of the frame 17 can be approximately 2.5 mm.

[0281] Figure 17E This is a schematic cross-section of a part of another new type of film 94. Figure 17E The novel film 94 shown is similar to Figure 17A The known film 82 shown, except that the novel film 94 has a higher... Figure 17A The known surface film 82 shown has a smaller width 86. Similarly, this moves the contact point between the frame 17 and the diaphragm 19 outward along at least one edge of the diaphragm 19, which reduces etching of the surface film.

[0282] Some embodiments of this disclosure relate to Figure 1 A photolithography apparatus of the type shown includes: a surface film comprising a frame 17 and a diaphragm 19 surrounded and supported by the frame 17; a hydrogen source; and an irradiation system IL arranged to irradiate the surface film with radiation; wherein a portion of the diaphragm 19 in contact with the frame 17 is located at a position not reached by EUV-induced hydrogen plasma.

[0283] Advantageously, because the portion of the diaphragm 19 in contact with the frame 17 is located at a position where EUV-induced hydrogen plasma does not diffuse, the diaphragm 19 experiences less etching from the hydrogen plasma. The surface film of such a photolithography apparatus may include... Figure 17B to Figure 17E One or more of the following films 88, 89, 90, and 94 are shown: Figure 18 and Figure 19 A novel type of film as shown.

[0284] Some embodiments of this disclosure relate to novel surface films used in lithography apparatus LA, which have been adapted to provide shielding to protect peripheral portions of diaphragm 19 from hydrogen plasma etching, as now referenced. Figure 18 to Figure 19 The subject of discussion.

[0285] Figure 18 A novel mask and a mask assembly 98 including a novel mask are shown according to embodiments of the present disclosure. Figure 19 It shows Figure 18 The image shows an enlarged portion of the novel photomask and film assembly 98. The novel film is intended for use in a photolithography apparatus LA and includes: a frame 17; a diaphragm 19 surrounded and supported by the frame 17; and shielding members 98a, 98b adjacent to the peripheral portion of the frame 17 adjacent to the diaphragm 19. The diaphragm 19 is generally flat and defines the plane of the film. The shielding members 98a, 98b are spaced apart from the diaphragm 19 in a direction generally perpendicular to the plane of the film.

[0286] exist Figure 18 and Figure 19 In the illustrated embodiment, the shielding member includes a first shielding member 98a adjacent to a first surface of the peripheral portion of the diaphragm 19, and a second shielding member 98b adjacent to a second surface of the peripheral portion of the diaphragm 19. The first surface may be a surface of the diaphragm that faces away from the mask MA during use (and may be referred to as the upper surface or front surface of the diaphragm). The second surface may be a surface of the diaphragm that faces the mask MA during use (and may be referred to as the lower surface or rear surface of the diaphragm). Alternative embodiments may include only one of the first shielding member 98a and the second shielding member 98b.

[0287] Because shielding elements 98a and 98b can protect the surface film from etching by plasma (e.g., EUV-induced hydrogen plasma) during use (e.g., in an EUV lithography machine LA), Figure 18 and Figure 19 The novel film shown is advantageous.

[0288] The conventional idea might be that the mask shielding blades 32, 34, 36, and 38 could be used as plasma shielding for the surface membrane. However, it has recently been found that the most etched area on the CNT diaphragm lies below the mask shielding blades 32, 34, 36, and 38 outside the exposure area (i.e., the portion 76 of the surface membrane that can receive EUV radiation) (indicating that the mask shielding blades 32, 34, 36, and 38 do not provide effective plasma shielding for the surface membrane). It is believed that the distance between the mask shielding blades 32, 34, 36, and 38 and the diaphragm 19 of the surface membrane is too large to provide effective shielding. Although in use, there is generally not a large space between the diaphragm 19 of the surface membrane and other components (e.g., the mask shielding blades 32, 34, 36, and 38), it is believed that sufficient space exists for the relatively thin shielding elements 98a and 98b, allowing Figure 18 and Figure 19 The novel film shown is used in existing lithography equipment LA.

[0289] The shielding elements 98a and 98b may extend beyond the boundary of the film, but remain outside the quality area (or a portion of the film corresponding to the image forming area of ​​the mask MA).

[0290] The first shielding member 98a and / or the second shielding member 98b may be directly or indirectly supported by the frame 17 or the support member 74.

[0291] The support 74 for the diaphragm, which facilitates connection to the mask MA, may include an additional or extended portion 74b that extends further away from the mask MA than the diaphragm 19. The first shielding member 98a may be configured as a cantilever structure extending from this additional or extended portion 74b.

[0292] The second shielding member 98b can be configured as a cantilever structure extending from the frame 17. For example... Figure 19 As shown, this can be achieved by setting the frame as two frame portions 17a, 17b, wherein the second shielding member 98b is sandwiched between the two frame portions 17a, 17b and extends from the two frame portions 17a, 17b adjacent to the diaphragm 19.

[0293] Will understand, Figure 18 and Figure 19 The novel film shown can include, as needed. Figure 17B to Figure 17E Any features of the novel film shown.

[0294] It may be desirable for the shields 98a and 98b to be as close as possible to the surface of the diaphragm 19, as this will minimize the amount of plasma diffusing beneath the shields 98a and 98b (i.e., between the shields 98a and 98b and the diaphragm 19), thereby maximizing plasma shielding. Typically, it may be desirable for the distance between the shields 98a and 98b and the surface of the diaphragm 19 to be less than the Debye length of the plasma (the Debye length can be less than 1 mm, or less than 0.2 mm during EUV pulses). It may also be desirable for the shields 98a and 98b to be far enough from the surface of the diaphragm 19 to allow for any sagging of the diaphragm 19 without the risk of the shields 98a and 98b contacting the surface of the diaphragm 19.

[0295] It will be understood that the first shielding member 98a and the second shielding member 98b can be positioned at different distances from the diaphragm 19. Alternatively, the first shielding member 98a and the second shielding member 98b can be positioned at substantially the same distance from the diaphragm 19.

[0296] The distance between shielding members 98a and 98b and diaphragm 19 can be less than 1 mm. It will be understood that the distance 114a between the first shielding member 98a and diaphragm 19 can be less than 1 mm, and / or the distance 114b between the second shielding member 98b and diaphragm 19 can be less than 1 mm. Specifically, the distance between the front surface of diaphragm 19 and the shielding member 98a adjacent to the front surface of diaphragm 19 can be less than 1 mm. The distance 114a between the first shielding member 98a and diaphragm 19 can be between 200 μm and 1000 μm. The distance 114a between the first shielding member 98a and diaphragm 19 can be between 400 μm and 800 μm. The distance 114b between the second shielding member 98b and diaphragm 19 can be between 200 μm and 1000 μm. The distance 114b between the second shielding member 98b and diaphragm 19 can be between 400 μm and 800 μm.

[0297] The shielding members 98a and 98b may have a thickness of less than 1 mm. The thickness 112a of the first shielding member 98a may be approximately 100 μm to 300 μm. The thickness 112b of the second shielding member 98b may be approximately 100 μm to 300 μm. In some embodiments, the shielding members 98a and 98b may have a thickness 112a and 112b of approximately 200 μm or less. The shielding members 98a and 98b having thicknesses 112a and 112b may be selected from readily available commercially available materials.

[0298] The shielding elements 98a and 98b may extend a distance 116 away from the frame 17 in the plane of the diaphragm 19. The distance 116 may be, for example, about 1 mm to 1.5 mm.

[0299] Preferably, the shields 98a and 98b may extend to cover a portion of the diaphragm 19 that would be adjacent to the plasma but not receive EUV radiation during use in the absence of the shields. The shields 98a and 98b may maintain a distance 118 away from the quality region of the surface film 78 (i.e., the portion of the surface film corresponding to the image forming region of the mask MA) such that the shields do not interfere with the EUV light cone. For example, the distance 118 may be approximately 0.5 mm to 1.5 mm.

[0300] The shielding elements 98a and 98b can be formed of a material that is transparent to the wavelength of radiation used to periodically heat the diaphragm during use.

[0301] For example, shielding elements 98a and 98b can be formed of a material that is transparent to infrared (IR) and / or deep ultraviolet (DUV) radiation. This allows shielding elements 98a and 98b to protect the diaphragm from the effects of plasma while still allowing the use of such radiation to periodically heat the diaphragm 19.

[0302] The shielding components 98a and 98b can be formed from materials that are inert in hydrogen plasma.

[0303] The shielding elements 98a and 98b may include sapphire (Al2O3). For example, the shielding elements 98a and 98b may include a glass material coated with sapphire (Al2O3). Alternatively, the shielding elements 98a and 98b may be formed of sapphire.

[0304] Some embodiments of this disclosure relate to Figure 1 A lithography apparatus LA of the type shown, comprising: a surface film including: a frame 17, a diaphragm 19 surrounded and supported by the frame 17, and shielding elements 98a, 98b adjacent to a peripheral portion of the frame 17 adjacent to the diaphragm 19; a hydrogen source; and an irradiation system IL arranged to irradiate the surface film with radiation; wherein the shielding elements 98a, 98b are adjacent to a portion of the diaphragm 19 to which EUV-induced hydrogen plasma would diffuse without such shielding.

[0305] Advantageously, since the shielding elements 98a, 98b are adjacent to a portion of the surface film to which EUV-induced hydrogen plasma would diffuse without such shielding elements 98a, 98b, the shielding elements 98a, 98b protect the diaphragm 19 from the effects of the plasma (and associated plasma etching) that would be present without such shielding elements 98a, 98b. The surface film of such a lithography apparatus LA may include, for example... Figure 17B to Figure 17E The novel film types 88, 89, 90, 94 and / or shown are... Figure 18 and Figure 19 A novel type of film as shown.

[0306] References to masks or mask plates in this document may be interpreted as references to pattern forming apparatus (of which masks or mask plates are examples) and the terms may be used interchangeably. Specifically, the term "mask assembly" is synonymous with "mask plate assembly" and "pattern forming apparatus assembly".

[0307] While specific reference to embodiments of the invention is made herein within the context of a photolithography apparatus, embodiments of the invention can be used in other apparatuses. Embodiments of the invention can form part of mask inspection apparatus, metrology apparatus, or any apparatus for measuring or processing objects such as wafers (or other substrates) or masks (or other patterning apparatus). These apparatuses are generally referred to as “photolithography tools.” Such photolithography tools can use vacuum conditions or ambient (non-vacuum) conditions.

[0308] The term “EUV radiation” can be considered to include electromagnetic radiation with wavelengths in the range of 4 nm to 20 nm, for example, in the range of 13 nm to 14 nm. EUV radiation can also have wavelengths less than 10 nm, for example, wavelengths in the range of 4 nm to 10 nm, such as 6.7 nm or 6.8 nm.

[0309] While this article provides specific examples of the use of lithography equipment in IC manufacturing, it should be understood that the lithography equipment described herein can have other applications. Other possible applications include the fabrication of integrated optical systems, patterning for magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0310] While specific embodiments of the invention have been described above, it will be understood that the invention can be practiced in ways other than those described. The foregoing description is intended to be illustrative and not restrictive. Therefore, those skilled in the art will appreciate that modifications can be made to the invention as described without departing from the scope of the claims and aspects set forth below.

[0311] 1. A photolithography method, comprising:

[0312] The image of the mask is formed multiple times on the substrate, and each such image formation process includes:

[0313] The first part of the mask and the film assembly is irradiated with a radiation beam; and

[0314] The radiation scattered by the mask is collected and projected onto a target area of ​​the substrate using projection optics; and

[0315] The second portion of the mask and film assembly is periodically irradiated with a radiation beam, the second portion of the mask and film assembly at least partially surrounding the first portion.

[0316] 2. The method according to aspect 1, wherein the second portion of the mask and the film assembly is periodically irradiated with a radiation beam by periodically irradiating an expanded exposure field.

[0317] 3. The method according to aspect 1 or aspect 2, wherein the second portion of the mask and the film assembly is periodically irradiated with a radiation beam by changing the exposure field.

[0318] 4. The method according to aspect 3, wherein the exposure field for at least some image forming processes is different from the exposure field for previous image forming processes.

[0319] 5. The method according to aspect 4, wherein at least one edge of the exposure field for each of the at least some image forming processes is shifted by an offset.

[0320] 6. The method according to aspect 3, wherein the exposure field for multiple image forming processes is continuously varied.

[0321] 7. The method according to any of the foregoing aspects, wherein, during each image formation process, at least one shielding blade is used to shield adjacent target areas of the substrate from being irradiated by the radiation beam.

[0322] 8. The method according to aspect 7 when directly or indirectly subordinate to aspect 2 or aspect 3, wherein the irradiation expansion exposure field or the change of exposure field is achieved by controlling the at least one shielding blade.

[0323] 9. The method according to aspect 7 or aspect 8, wherein the position of the at least one masking blade is manipulated such that the perimeter of the exposure area expands over the extended area.

[0324] 10. The method according to any one of aspects 7 to 9, wherein four masking blades are used during exposure of each target region to define the exposure field, and wherein, for each target region adjacent to an edge of the substrate, at least one of the masking blades corresponding to an edge of the exposure field adjacent to the edge of the substrate is positioned to expand the exposure field.

[0325] 11. The method according to any of the foregoing aspects, wherein forming an image of a mask multiple times on a substrate comprises: forming the image of the mask on a plurality of target regions of the substrate, the plurality of target regions being arranged in a two-dimensional array, wherein the two-dimensional array of target regions is exposed one row at a time, and wherein the rows are exposed out of order.

[0326] 12. The method according to any of the foregoing aspects, wherein each image forming process includes a scanning exposure in which the mask and the film assembly are moved relative to the radiation beam along a scanning direction.

[0327] 13. The method according to any of the foregoing aspects when directly or indirectly subordinate to aspect 2, wherein, when the expanded exposure field is periodically irradiated, the radiation scattered from the mask and the film assembly is not projected onto the substrate.

[0328] 14. The method according to any of the foregoing aspects, wherein periodically irradiating a second portion of the mask and the film assembly with a radiation beam comprises: exposing the second portion to EUV radiation to heat the film to a temperature at which the hydrogen etching rate of the film can be negligible.

[0329] 15. The method according to any of the foregoing aspects, wherein the second portion of the mask and the film assembly is periodically irradiated with a radiation beam such that the second portion of the mask and the film assembly is irradiated once for each substrate.

[0330] 16. The method according to any of the foregoing aspects, wherein the second portion of the mask and the film assembly is periodically irradiated with a radiation beam such that the second portion of the mask and the film assembly is irradiated once for each row of target areas on the substrate.

[0331] 17. A photolithography component of a photolithography apparatus, the photolithography component comprising:

[0332] A support structure configured to support a mask and a surface assembly for receiving radiation beams; and

[0333] A controller, operable to control the support structure and / or the radiation beam, so as to:

[0334] (a) Forming multiple images of a mask supported by the support structure on a substrate, each such image formation process comprising: irradiating the mask and a first portion of the film assembly with the radiation beam; and projecting the radiation scattered by the mask onto a target area of ​​the substrate using projection optics; and

[0335] (b) Periodically irradiate a second portion of the mask and film assembly with the radiation beam, the second portion of the mask and film assembly at least partially surrounding the first portion.

[0336] 18. The lithography component according to aspect 17, wherein the controller is operable to implement the method according to any one of aspects 1 to 16.

[0337] 19. The photolithography component according to aspect 17 or aspect 18 further includes a scanning mechanism operable to move the support structure relative to the radiation beam in a scanning direction.

[0338] 20. The photolithography component according to any one of aspects 17 to 19, further comprising:

[0339] The first pair of shielding blades are arranged to define the exposure area in a first direction; and

[0340] The second pair of shielding blades is arranged to define the exposure area in the second direction.

[0341] 21. The photolithography apparatus according to aspect 20 when subordinate to aspect 19, wherein the first direction is the scanning direction, and wherein, in order to form an image of a mask supported by the support structure on a target area of ​​the substrate, the controller is operable to:

[0342] Control the scanning mechanism to move the mask supported by the support structure through the exposure area; and

[0343] The position of the first pair of shielding blades is controlled to shield the adjacent target area of ​​the substrate from being irradiated by the radiation beam.

[0344] 22. A lithography component according to any one of aspects 17 to 21 when directly or indirectly subordinate to aspect 20, wherein, in order to irradiate the second portion of the mask and film assembly with the radiation beam, the controller is operable to control the first pair of shielding blades and / or the second pair of shielding blades to irradiate an expanded exposure field.

[0345] 23. A photolithography component according to any one of aspects 17 to 22 when directly or indirectly subordinate to aspect 20, wherein, in order to irradiate the second portion of the mask and film assembly with the radiation beam, the controller is operable to control the first pair of shielding blades and / or the second pair of shielding blades to change the exposure field.

[0346] 24. The lithography component according to aspect 23, wherein the controller is operable to control the first pair of masking blades and / or the second pair of masking blades such that the exposure field for at least some image forming processes is different from the exposure field for previous image forming processes.

[0347] 25. The lithography component according to aspect 24, wherein the controller is operable to control the first pair of masking blades and / or the second pair of masking blades such that at least one edge of the exposure field for each of at least some image forming processes is shifted by an offset.

[0348] 26. The photolithography component according to aspect 23, wherein the controller is operable to control the first pair of masking blades and / or the second pair of masking blades such that the exposure field for multiple image forming processes is continuously varied.

[0349] 27. A photolithography component according to any one of aspects 17 to 26 when directly or indirectly subordinate to aspect 20, wherein, in order to irradiate the second portion of the mask and film assembly with the radiation beam, the controller is operable to control the first pair of masking blades and / or the second pair of masking blades such that the perimeter of the exposure area expands over the extended region.

[0350] 28. A photolithography component according to any one of aspects 17 to 27 when directly or indirectly subordinate to aspect 20, wherein, in order to irradiate the second portion of the mask and the film assembly with the radiation beam, the controller is operable to control the first pair of masking blades and / or the second pair of masking blades such that, when an image of the mask supported by the support structure is formed on a target region of the substrate adjacent to the edge of the substrate, at least one of the masking blades corresponding to the edge of the exposure field adjacent to the edge of the substrate is positioned to expand the exposure field.

[0351] 29. The photolithography component according to any one of aspects 17 to 28, wherein when the second portion of the mask and the film assembly is irradiated with the radiation beam, the controller is operable to heat the film to a temperature at which the hydrogen etching rate of the film can be negligible.

[0352] 30. A photolithography apparatus comprising the components described in any one of aspects 17 to 29.

[0353] 31. The photolithography apparatus according to aspect 30 further includes:

[0354] An irradiation system configured to modulate the radiation beam received by the mask and the film assembly;

[0355] Substrate stage, the substrate stage being configured to support a substrate; and

[0356] A projection system configured to receive the radiation beam from the mask and film assembly and project the radiation beam onto the substrate.

[0357] 32. A coating for use in a photolithography apparatus, the coating comprising:

[0358] Framework; and

[0359] A diaphragm, the diaphragm being surrounded and supported by the frame;

[0360] The diaphragm is generally flat and defines the plane of the surface membrane;

[0361] The frame has a thickness substantially perpendicular to the plane of the surface film and a width substantially parallel to the plane of the surface film; and

[0362] Wherein, in the plane of the membrane, the outer portion of the frame contacts the diaphragm, and along at least one edge of the diaphragm, the inner portion of the frame has a reduced thickness relative to the outer portion of the frame, such that the inner portion of the frame does not contact the diaphragm.

[0363] 33. The film according to aspect 32, wherein the recess formed between the inner portion of the frame having a reduced thickness and the diaphragm has a substantially uniform thickness.

[0364] 34. The film according to aspect 32, wherein the recess formed between the inner portion of the frame having a reduced thickness and the diaphragm has a thickness that varies from the inner edge of the frame to the outer portion of the frame.

[0365] 35. The film according to any one of aspects 32 to 34, wherein the width of the inner portion of the frame having a reduced thickness is greater than 2.2 mm.

[0366] 36. A photolithography apparatus, comprising:

[0367] A membrane, the membrane comprising a frame and a diaphragm surrounded and supported by the frame;

[0368] Hydrogen source; and

[0369] An irradiation system, the irradiation system being arranged to irradiate the surface film with radiation;

[0370] The portion of the diaphragm that contacts the frame is positioned at a location where EUV-induced hydrogen plasma does not diffuse.

[0371] 37. A coating for use in a photolithography apparatus, the coating comprising:

[0372] frame;

[0373] A diaphragm, the diaphragm being surrounded and supported by the frame; and

[0374] A shielding element, wherein the shielding element is adjacent to the peripheral portion of the diaphragm that is adjacent to the frame;

[0375] The diaphragm is generally flat and defines the plane of the surface membrane; and

[0376] The shielding element is spaced apart from the diaphragm in a direction substantially perpendicular to the plane of the surface membrane.

[0377] 38. The membrane according to aspect 37, wherein the shielding member includes a first shielding member adjacent to a first surface of the peripheral portion of the membrane and a second shielding member adjacent to a second surface of the peripheral portion of the membrane.

[0378] 39. The membrane according to aspect 37 or aspect 38, wherein the distance between the shielding member and the diaphragm is less than 1 mm.

[0379] 40. The film according to any one of aspects 37 to 39, wherein the shielding member has a thickness of less than 1 mm.

[0380] 41. The membrane according to any one of aspects 37 to 40, wherein the shielding member extends about 1 mm to 1.5 mm away from the frame on the membrane.

[0381] 42. The film according to any one of aspects 37 to 41, wherein the shielding member is formed of a material that is transparent to the wavelength of radiation used for periodically heating the film during use.

[0382] 43. The film according to any one of aspects 37 to 42, wherein the shielding element is formed of a material that is inert in hydrogen plasma.

[0383] 44. The film according to any one of aspects 37 to 43, wherein the shielding element comprises sapphire (Al2O3).

[0384] 45. A photolithography apparatus, comprising:

[0385] The membrane includes: a frame, a diaphragm surrounded and supported by the frame, and a shielding member adjacent to a peripheral portion of the diaphragm adjacent to the frame;

[0386] Hydrogen source; and

[0387] An irradiation system, the irradiation system being arranged to irradiate the surface film with radiation;

[0388] The shielding element is adjacent to a portion of the membrane to which EUV-induced hydrogen plasma would diffuse without such a shielding element.

Claims

1. A lithographic apparatus of a lithographic apparatus, the lithographic apparatus comprising: a support structure configured to support a reticle and pellicle assembly for receiving a beam of radiation; and a controller operable to control the support structure and / or the beam of radiation so as to: (a) form an image of the reticle supported by the support structure on a substrate a plurality of times, each such image formation process comprising: illuminating a first portion of the reticle and pellicle assembly with the beam of radiation; and using projection optics to project radiation scattered by the reticle onto a target area of the substrate; and (b) periodically illuminate a second portion of the reticle and pellicle assembly with the beam of radiation, the second portion of the reticle and pellicle assembly at least partially surrounding the first portion.

2. The lithography component of claim 1, wherein, The controller is operable to implement a method according to any of claims 16 to 31.

3. The lithographic apparatus of claim 1 or claim 2, further comprising a scanning mechanism operable to move the support structure in a scan direction relative to the beam of radiation.

4. The lithographic apparatus of any of claims 1 to 3, further comprising: a first pair of shutter blades arranged to define a range of an exposure area in a first direction; and a second pair of shutter blades arranged to define a range of an exposure area in a second direction. The first direction is the scan direction, and wherein, to form an image of the reticle supported by the support structure on a target area of a substrate, the controller is operable so as to:

5. The lithography component according to claim 4 when dependent on claim 3, wherein, control the scanning mechanism so as to move the reticle supported by the support structure through the exposure area; and control the position of the first pair of shutter blades so as to shield adjacent target areas of the substrate from being illuminated by the beam of radiation. To illuminate the second portion of the reticle and pellicle assembly with the beam of radiation, the controller is operable to control the first pair of shutter blades and / or the second pair of shutter blades so as to illuminate an enlarged exposure field.

6. The lithography member according to any of claims 1 to 5 when dependent directly or indirectly on claim 4, wherein, To illuminate the second portion of the reticle and pellicle assembly with the beam of radiation, the controller is operable to control the first pair of shutter blades and / or the second pair of shutter blades so as to vary the exposure field.

7. The lithography member according to any of claims 1 to 6 when dependent directly or indirectly on claim 4, wherein, The controller is operable to control the first pair of shutter blades and / or the second pair of shutter blades so that the exposure field for at least some image formation processes differs from the exposure field for a preceding image formation process.

8. The lithography component of claim 7, wherein, The controller is operable to control the first pair of shutter blades and / or the second pair of shutter blades so that at least one edge of the exposure field for each of at least some image formation processes is shifted by an offset amount.

9. The lithography component of claim 8, wherein, The controller is operable to control the first pair of shutter blades and / or the second pair of shutter blades so that the exposure field for a plurality of image formation processes varies continuously.

10. The photolithography component of claim 7, wherein, ​ 11. The lithography member of any of claims 1-10, when dependent directly or indirectly on claim 4, wherein, To irradiate the second portion of the reticle and pellicle assembly with the beam of radiation, the controller is operable to control the first and / or second pairs of masking vanes such that a perimeter line of the exposure field is unrolled over an extended area.

12. The lithography member of any of claims 1 to 11 when dependent directly or indirectly on claim 4, wherein, To irradiate the second portion of the reticle and pellicle assembly with the beam of radiation, the controller is operable to control the first and / or second pairs of masking vanes such that at least one of the masking vanes corresponding to an edge of the exposure field adjacent to an edge of the substrate is positioned to enlarge the exposure field when forming an image of a reticle supported by the support structure on a target area of a substrate adjacent to the edge of the substrate.

13. The lithography component of any one of claims 1 to 12, wherein, To irradiate the second portion of the reticle and pellicle assembly with the beam of radiation, the controller is operable to heat the pellicle to a temperature at which a hydrogen etch rate of the pellicle is negligible.

14. A lithographic apparatus comprising the component of any of claims 1 to 13.

15. The lithographic apparatus of claim 14, further comprising: an illumination system configured to condition the beam of radiation received by the reticle and pellicle assembly; a substrate table constructed to support a substrate; and a projection system configured to receive the beam of radiation from the reticle and pellicle assembly and to project the beam of radiation onto the substrate.

16. A lithographic method comprising: forming multiple images of a reticle on a substrate, each such image forming process comprising: irradiating a first portion of a reticle and pellicle assembly with a beam of radiation; and collecting radiation scattered by the reticle and projecting the radiation using projection optics onto a target area of a substrate; and periodically irradiating a second portion of the reticle and pellicle assembly with a beam of radiation, the second portion of the reticle and pellicle assembly at least partially surrounding the first portion. Periodically irradiating the second portion of the reticle and pellicle assembly with a beam of radiation is achieved by irradiating an enlarged exposure field.

17. The method of claim 16, wherein, Periodically irradiating the second portion of the reticle and pellicle assembly with a beam of radiation is achieved by changing an exposure field.

18. The method of claim 16 or claim 17, wherein, The exposure field used for at least some of the image forming processes is different from the exposure field used for a previous image forming process.

19. The method of claim 18, wherein, At least one edge of the exposure field used for each of at least some of the image forming processes is shifted by an offset.

20. The method of claim 19, wherein, The exposure field used for a plurality of image forming processes is continuously varied.

21. The method of claim 18, wherein, During each image forming process, at least one masking vane is used to mask an adjacent target area of the substrate from being irradiated by the beam of radiation.

22. The method of any preceding claim, wherein, Irradiating an enlarged exposure field or changing an exposure field is achieved by controlling the at least one masking vane.

23. The method according to claim 22 when directly or indirectly dependent on claim 2 or claim 3, wherein, The position of the at least one reticle masking vane is manipulated such that a perimeter line of the exposure field is unrolled over an extended area.

24. The method of claim 22 or claim 23, wherein, ​ 25. The method of any one of claims 22-24, wherein, The four masking blades are used during exposure of each target area to define the exposure field, and wherein for each target area adjacent to an edge of the substrate, at least one of the masking blades corresponding to an edge of the exposure field adjacent to the edge of the substrate is positioned to enlarge the exposure field.

26. The method of any preceding claim, wherein, Forming images of a mask on a substrate a plurality of times comprises forming images of the mask on a plurality of target areas of the substrate, the plurality of target areas being arranged as a two-dimensional array, wherein the two-dimensional array of target areas is exposed one row at a time, and wherein the rows are not exposed in order.

27. The method of any preceding claim, wherein, Each image forming process comprises a scan exposure in which the mask and pellicle assembly are moved relative to the beam of radiation in a scan direction.

28. The method according to any preceding claim when directly or indirectly dependent on claim 17, wherein, When the enlarged exposure field is illuminated periodically, the radiation scattered from the mask and pellicle assembly is not projected onto the substrate.

29. The method of any preceding claim, wherein, Periodically illuminating the second portion of the mask and pellicle assembly with a beam of radiation comprises exposing the second portion to EUV radiation to heat the pellicle to a temperature at which the hydrogen etch rate of the pellicle is negligible.

30. The method of any preceding claim, wherein, Periodically illuminating the second portion of the mask and pellicle assembly with a beam of radiation is such that the second portion of the mask and pellicle assembly is illuminated once for each substrate.

31. The method of any preceding claim, wherein, Periodically illuminating the second portion of the mask and pellicle assembly with a beam of radiation is such that the second portion of the mask and pellicle assembly is illuminated once for each row of target areas on a substrate.

Images