Lithographic apparatus and associated methods

Abstract

A method is provided for configuring a photolithography apparatus including an irradiator optics for guiding at least a portion of a radiation beam to an irradiation region of a patterning apparatus to impart a pattern to the radiation beam and form a patterned radiation beam. The method includes configuring the irradiator optics such that at least two different portions of the patterning apparatus receive radiation from different regions of the irradiator optics within a pupil plane associated with the irradiator optics, the at least two different portions being different at least in position along a scanning direction of the irradiation region.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Application 63 / 618,079, filed January 5, 2024, and European Application 24153301.7, filed January 23, 2024, both of which are incorporated herein by reference in their entirety. Technical Field

[0002] This invention relates to photolithography equipment. It also relates to a corresponding method for forming patterns on a target area of ​​a substrate. The photolithography equipment and method can utilize extreme ultraviolet (EUV) radiation. Background Technology

[0003] A photolithography apparatus is a machine configured to apply a desired pattern onto a substrate. Photolithography apparatus can be used, for example, to manufacture integrated circuits (ICs). A photolithography apparatus can, for example, project a pattern at a patterning device (e.g., a mask) onto a radiation-sensitive material (resist) layer disposed on a substrate.

[0004] To project patterns onto a substrate, photolithography equipment can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be formed on the substrate. Compared to photolithography equipment that uses radiation with a wavelength of, for example, 193 nm, photolithography equipment that uses extreme ultraviolet (EUV) radiation in the 4-20 nm range (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on the substrate.

[0005] It is desirable to provide control over various properties of the radiation beam used in a photolithography apparatus to project a pattern onto a substrate. For example, it is desirable to monitor the energy of the radiation beam to allow control over the radiation dose delivered to the substrate. Furthermore, it is desirable to provide control over the shape (i.e., spatial distribution) of the radiation beam within the plane of the patterning apparatus. Additionally, it is desirable to provide control over the angular distribution of the radiation beam within the plane of the patterning apparatus. The angular distribution of the radiation beam within the plane of the patterning apparatus can be referred to as the illumination mode, which can be selected based on the pattern being imaged to increase image contrast on the substrate.

[0006] It may be desirable to provide new, alternative lithography equipment and / or methods that at least partially address one or more problems associated with existing art arrangements, whether identified herein or elsewhere. Summary of the Invention

[0007] In a first aspect, a method is provided for configuring a lithography apparatus including an irradiator optics for guiding at least a portion of a radiation beam to an irradiation region of a patterning apparatus to impart a pattern to the radiation beam and form a patterned radiation beam. The method includes: configuring the irradiator optics such that at least two distinct portions of the patterning apparatus receive radiation from different regions within a pupil plane associated with the irradiator optics, the at least two distinct portions being different in position at least along a scanning direction of the irradiation region; receiving radiation having a first angular distribution at a first portion of the irradiation region and receiving radiation having a second angular distribution at a second portion of the irradiation region, wherein the first portion and the second portion are separated in the scanning direction, wherein alignment of a spatial image associated with features on the patterning apparatus depends on the coordinates of the radiation beam in the pupil plane; and correcting spatial image displacement associated with differences between portions of the irradiation region. Attached Figure Description

[0008] Embodiments of the invention will now be described by way of example only, with reference to the accompanying schematic diagrams, wherein: Figure 1 A lithography system including lithography equipment and a radiation source is shown; Figure 2a schematically shown Figure 1 The roughly circular portion of the field-matrix mirror device of the photolithography system shown illustrates the central shielding portion of the two parts that receive radiation. Figure 2b It shows Figure 1 An example shape of the field surface of a faceted field mirror device in a known EUV lithography apparatus, as shown; Figure 3a and 3b The diagram shows a first optical element (or faceted pupil mirror device) not positioned in or conjugate with the entrance pupil of the projection system, and a first position of the entrance pupil of the projection system in the illumination area (see [reference]). Figure 3a ) and the second position in the irradiated area (see Figure 3b A simplified and schematic representation of the projection (the ring represented by the dashed line) onto the first optical element. Figure 4a The first position for use in the irradiation area is shown (e.g.) Figure 3a Irradiation mode (as shown); Figure 4b A second position (e.g.) is shown in the irradiation area. Figure 3b Irradiation mode (as shown); Figure 5 This is a schematic diagram of an embodiment of the irradiation system according to the present disclosure; Figure 6This is a schematic diagram of an embodiment of an irradiation system according to the present disclosure, the irradiation system including a second optical element comprising a plurality of focusing elements, each set of focusing elements being arranged to direct radiation to different portions of a plurality of portions of an irradiation area; Figure 7 It is a graph of irradiation intensity (I) versus (vs.) the length of the irradiated area (y) in the scanning direction; Figure 8 This is a schematic diagram of an embodiment of an irradiation system according to the present disclosure, the irradiation system including a second optical element comprising a plurality of focusing elements, each set of focusing elements being arranged to direct radiation to different portions of a plurality of portions of an irradiation area. Figure 9 a and 9b are representations of the focal plane. Figure 10 This diagram illustrates the overlay error caused by a locally tilted wafer surface and methods to reduce overlay error. Figure 11 This illustrates the decomposition of the six-pole irradiation mode into a dynamic irradiation distribution consisting of two rotating tripolar irradiation modes. Figure 12 This demonstrates the decomposition of the six-pole irradiation mode into three rotating dipole irradiation modes. Detailed Implementation

[0009] Figure 1 A lithography system including a radiation source SO and a lithography apparatus LA is shown. The radiation source SO is configured to generate an EUV radiation beam B and provide the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an irradiation system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS, and a substrate stage WT configured to support a substrate W.

[0010] The irradiation system IL is configured to adjust the EUV radiation beam B before it is incident on the patterning device MA. Furthermore, 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 the EUV radiation beam B with the desired cross-sectional shape and desired intensity distribution. The irradiation system IL may include other mirrors or devices attached to or replacing the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11.

[0011] The lithography apparatus LA also includes a controller CN, which is operable to control the configuration of the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11. To achieve this, the controller CN is operable to send appropriate control signals s1, s2 to each of the faceted pupil mirror assembly 11 and the faceted field mirror assembly 10.

[0012] After such adjustment, the EUV radiation beam B interacts with the patterning device MA. As a result of this interaction, a patterned EUV radiation beam B' is generated. A projection system PS is configured to project the patterned EUV radiation beam B' onto a substrate W. For this purpose, the projection system PS may include a plurality of mirrors 13, 14, configured to project the patterned EUV radiation beam B' onto the substrate W held by the substrate stage WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B', thereby forming an image with features smaller than the corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 can be applied. Although in Figure 1 The projection system PS is shown as having only two mirrors 13 and 14, but the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0013] The substrate W may include a previously formed pattern. In this case, the photolithography apparatus LA aligns the image formed by the patterned EUV radiation beam B' with the pattern previously formed on the substrate W.

[0014] A relative vacuum, i.e., a small amount of gas (e.g., hydrogen) at a pressure much lower than atmospheric pressure, can be provided in the radiation source SO, the irradiation system IL, and / or the projection system PS.

[0015] For example, Figure 1 The radiation source SO shown is of the type that can be called a laser-generated plasma (LPP) source. A laser system 1, which may include, for example, a CO2 laser, is arranged to deposit energy into a fuel, such as tin (Sn) supplied, for example, from a fuel emitter 3, via a laser beam 2. Although tin is mentioned in the description below, 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 may include a nozzle configured to guide tin, for example, in droplet form, along a trajectory toward a plasma forming region 4. The laser beam 2 is incident on the tin at the plasma forming region 4. The laser energy deposited into the tin creates a tin plasma 7 at the plasma forming region 4. During the deexcitation and recombination of electrons and ions in the plasma, radiation, including EUV radiation, is emitted from the plasma 7.

[0016] EUV radiation from the plasma is collected and focused by collector 5. Collector 5 includes, for example, a near-vertical incident radiation collector 5 (sometimes more generally referred to as a vertical incident radiation collector). Collector 5 may have a multi-layered mirror 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 structure with two focal points. 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, as described below.

[0017] Laser system 1 can be spatially separated from radiation source SO. In this case, laser beam 2 can be transmitted from laser system 1 to radiation source SO by means of a beam delivery system (not shown) including, for example, suitable directional mirrors and / or beam expanders and / or other optical devices. Laser system 1, radiation source SO, and beam delivery system can be considered together as a radiation system.

[0018] The radiation reflected by collector 5 forms an EUV radiation beam B. The EUV radiation beam B is focused at intermediate focus 6 to form an image of the plasma present in plasma formation region 4 at intermediate focus 6. The image at intermediate focus 6 serves as a virtual radiation source for the irradiation system IL. The radiation source SO is arranged such that intermediate focus 6 is located at or near the opening 8 in the enclosed structure 9 of the radiation source SO.

[0019] although Figure 1 The radiation source SO is described as a laser-generated plasma (LPP) source, but any suitable source, such as a discharge-generated plasma (DPP) source or a free-electron laser (FEL), can be used to generate EUV radiation.

[0020] The faceted field reflector assembly 10 and the faceted pupil reflector assembly 11 are arranged to provide a desired angular distribution of the radiation beam B at the patterning device MA, and a desired uniformity of radiation intensity at the patterning device MA. The angular distribution of radiation at the patterning device MA can be referred to as the illumination mode. It can also be referred to as the pupil or pupil fill. The illumination system IL can be arranged to provide Kohler illumination of the illumination region IR (through which the patterning device MA can move during exposure of the substrate W), such that the plasma at the plasma formation region 4 is defocused at the patterning device MA and in the conjugate plane of the substrate W (and therefore does not affect the characteristics of the radiation beam). As used herein, the illumination region IR can also be referred to as the illumination slit or slit. The illumination region may include the unique region of the patterning device illuminated at any given time by at least a portion of the EUV radiation beam B.

[0021] In photolithography, the illumination of the patterning apparatus MA is crucial. Specifically, it is desirable to control the angular distribution of radiation at the irradiated region IR of the patterning apparatus MA, where it is exposed to radiation. This angular distribution is conveniently described by the spatial distribution of radiation in the illumination pupil plane, which describes how the light cone incident on each point of the patterning apparatus MA is filled. In a conventional illumination mode, radiation uniformly fills a circular region of the illumination pupil plane centered on the optical axis, such that each point on the patterning apparatus is illuminated by a solid light cone. In a dipole illumination mode, radiation fills two regions of the illumination pupil plane, spaced apart from and located on opposite sides of the optical axis. Many other illumination modes are known. In principle, an optimal illumination mode can be defined to image a given pattern under given conditions. Therefore, flexibility in illumination modes is desirable.

[0022] Irradiation uniformity is also very important. Irradiation uniformity affects the uniformity of the dose exposed to the target portion of the substrate W, which affects critical size uniformity (CDU), an important measure of the size uniformity of features formed on the substrate W. For example, it may be desirable to maintain a desired spatial intensity distribution of radiation across the irradiated region IR. As used herein, the spatial intensity distribution of radiation across the irradiated region IR can be referred to as the slit profile.

[0023] Collector 5 is typically in the form of a concave reflector, configured to collect radiation emitted from plasma formation region 4 into a solid angle facing collector 5. This radiation is reflected and focused at intermediate focus 6. Consequently, within the housing, radiation beam B typically has the form of a converging radiation cone that converges at intermediate focus 6, with the outer edge of the cone... Figure 1 The image is represented by two lines. Downstream of the intermediate focal point 6, the radiation beam B is typically in the form of a diverging cone, incident on a field-faceted reflector assembly 10, which is typically circular. However, the radiation source SO may include a shield that blocks a portion of this radiation cone, so that certain parts of the diverging cone will not receive radiation from the collector 5. For example, the radiation source SO may include a shield (not shown) arranged to prevent the laser beam 2 from propagating through the opening 8 and entering the lithography apparatus LA (which could potentially damage optical components). This shield may be supported by a closed structure via a support (not shown). The shield and the support together form a shield for the radiation source SO. Thus, as... Figure 2a As schematically shown, the generally circular portion 20 of the field-faceted reflector device 10 may include a central portion 22 and two portions 24, 26. The central portion 22 coincides with the shield of the radiation source SO and does not receive any radiation, while the two portions 24, 26 receive radiation. It should be understood that this is schematic, and the shield can have any shape or construction.

[0024] Now for reference Figure 2a and 2b Description in Figure 1 The known faceted field mirror device 10 used in EUV lithography equipment of the type shown.

[0025] In known EUV lithography equipment, the faceted field mirror assembly 10 includes multiple field faces. Specifically, in such known EUV lithography equipment, portions 24 and 26 of the faceted field mirror assembly 10 that receive radiation from the radiation source SO are provided with multiple field faces. For example, portions 24 and 26 of the faceted field mirror assembly 10 that receive radiation from the radiation source SO can have on the order of 100 field faces (e.g., 300 field faces). In the plane of the faceted field mirror assembly 10, each field facet can have a curved shape 28, such as... Figure 2b As shown in the diagram. Typically, in the plane of the faceted field mirror assembly 10, each field facet may have an elongated shape, having a longer dimension in the x-direction and a shorter dimension in the y-direction. Each field facet includes a mirror, which can be arranged to image the intermediate focal point 6 onto the faceted pupil mirror assembly 11. To achieve this, the field facet may, for example, be concave.

[0026] The faceted pupil mirror assembly 11 includes a plurality of pupil facets. The faceted pupil mirror assembly 11 is arranged to project an image of each field facet of the faceted field mirror assembly 10 onto an illumination region IR (also referred to as a slit or illumination slit) at the patterning device MA. The illumination system IL is configured such that each field facet is imaged on the illumination region IR in an overlapping manner. Desiredly, in this known lithography apparatus, each image of the field facet fills the illumination region IR. The overlap of the field facet images at least partially cancels out irregularities in the radiation beam B provided by the radiation source SO.

[0027] The irradiation region IR can be curved or straight. Typically, in scanning lithography (LA) equipment, the irradiation region IR is elongated, with a longer dimension and a shorter dimension. The shorter dimension may align with the scanning direction of the support structure MT, while the longer dimension may align with the non-scanning direction. The irradiation region IR can be curved or straight. The irradiation region IR in... Figure 1 As shown in the figure, Figure 1 A cross-section of the patterning device is shown. The longer dimension (along the x-direction) of the irradiation area IR is perpendicular to... Figure 1 The plane, while the shorter dimension of the irradiated area IR (along the y-direction) is located in Figure 1 Within the plane.

[0028] It should be understood that the irradiation area IR can have a shape in the plane of the patterning device MA that typically corresponds to each field facet, for example, typically has Figure 2bThe shape 28 shown is an example. Note that the shape and size of the projection of each field facet onto the plane of the patterning device MA may not be exactly the same as the illumination region IR, and will depend on the magnification factors applied in the x and y directions by the field facets, the pupil facets (and any other optics upstream of the illumination region IR). The edge of the illumination region IR can be defined by two sets of scribe mask blades (not shown) that can cut off radiation so that the radiation does not incident on the patterning device outside the illumination region IR. Therefore, in such a known photolithography apparatus, each field facet can be arranged such that, without such scribe mask blades, each would overfill the illumination region IR. The illumination region IR can receive radiation from the central portion of each field facet, as... Figure 2b The dashed line 29 is shown within the example shape 28 of the field facet.

[0029] Therefore, in some existing EUV lithography equipment, the area surrounding the irradiation region IR is also provided with EUV radiation (although the portion of the irradiation region at the patterning device MA from the EUV-radiated substrate W is masked). This area surrounding the irradiation region IR can be obtained from the edge portions of each field-faceted mirror (which may be arranged at the dashed lines 29 and...). Figure 2b The portion of the shape between the edges in the schematic illustration receives EUV radiation. At least a portion of this portion of EUV radiation not used to expose the substrate W can be incident on an energy sensor, which can be used to monitor and control the radiation dose delivered to the substrate W.

[0030] Faceted field mirror devices 10 and / or faceted pupil mirror devices 11 with a large number of individually oriented or movable reflective optical elements have been proposed to better control the illumination mode of lithography equipment. For example, faceted field mirror devices 10 and / or faceted pupil mirror devices 11 including microelectromechanical systems (MEMS) micromirror arrays have been proposed.

[0031] In a typical lithography system, a pattern on a mask is illuminated, and the resulting diffraction levels are collected and projected to form an aerial image at the wafer level. This aerial image can trigger photochemical reactions in the photoresist layer on the wafer. Therefore, the pattern can be transferred from the mask to the wafer. EUV lithography tools can use EUV reflective masks, which can consist of a multilayer stack with EUV reflective and EUV absorbent portions to define the pattern. For example, a typical EUV mask in high-volume manufacturing scenarios can use a tantalum (Ta) absorber. In some cases, such as when the pattern is highly regular and / or dense, the EUV mask may include an attenuation phase-shifting mask.

[0032] Typical EUV systems optimize the illumination pupil (often referred to as "pupil shape" or "source") to increase printability and achieve high throughput for a given pattern on a mask. However, typical EUV irradiators may lack the flexibility to manipulate the angular distribution of radiation exposing the mask within the exposure field (i.e., different controllable pupils for different portions of the exposure field, each corresponding to a different portion of the mask). Therefore, it may be impossible to control the pupil within the exposure field. This lack of flexibility can be inherent in the optical design of the irradiation system.

[0033] Typically, a transmission or reflection mask comprises a large number of features. Each feature is imaged onto a wafer subjected to a variety of imaging conditions, where a specific illumination shape (pupil) is received by the feature. In most photolithography tools, the individual source points of the illumination source (e.g., corresponding to a specific angle of incidence on the mask) are independent of each other. A spatial image of the features can then be constructed by summing all the corresponding individual spatial images over the illumination pupil, each individual spatial image being associated with a specific angle of incidence of the illumination beam at the mask.

[0034] Reflective masks (e.g., EUV masks) can have phase shifts between diffraction orders that are related to the incident / diffraction angle. This can lead to misalignment of the spatial image at the wafer level between different incident angles. For masks based on absorption and reflection (e.g., Ta masks), this effect is called the "mask 3D effect." When the pupil shape includes a wide range of illumination angles, the spatial image will effectively be the sum of many individually offset spatial images, each associated with a corresponding angle across the wide range of illumination angles. The resulting spatial image is then said to have undergone so-called M3D fading, which is essentially a blurring of the mask image. M3D fading can also persist in attenuating phase-shifted masks. The main drawback of M3D fading is the loss of contrast. For example, the optimal pupil for a particular use case could be a y-dipole. The wafer-level spatial image could be a superposition of the north and south poles of a y-dipole. Experimentally, spatial images from the north and south poles can be aligned at the wafer level to achieve optimal contrast. In fact, due to the mask 3D effect, spatial images corresponding to the North and South Poles may be misaligned (shifted relative to each other), which may cause the aforementioned blurring (M3D attenuation) of the mask image, resulting in a loss of contrast.

[0035] The described M3D attenuation effect is most pronounced for pupil shapes characterized by large intervals between single poles. Thus, for example, dipole, tetrapole, and hexapole, where the poles are located at or near the edge of the illuminator pupil.

[0036] Duo-monopole dual-exposure (as described in WO2020221556, incorporated herein by reference) overcomes the aforementioned drawbacks in some cases. However, when implementing the duo-monopole dual-exposure method, two exposures are required to effectively halve the throughput. By exposing only one monopole, most of the light in the complementary monopole may be lost, potentially leading to a loss of throughput. Two separate exposures could be used at lower doses, one for the Arctic and one for the Antarctic, but this could result in additional overhead losses between exposures, and the low dose could lead to stage-limited throughput.

[0037] In some cases, attenuation compensation techniques such as projection optics box (POB) attenuation injection (as described in WO2023104419A1, incorporated herein by reference) have been used to partially overcome the aforementioned drawbacks of double monopole exposure. POB attenuation injection can provide only partial recovery of the contrast loss caused by the M3D effect. For example, POB attenuation injection can compensate for spatial misalignment by shifting the spatial images of the North and South Poles in the dipole region to their nominal positions, thereby compensating for the M3D effect. However, the previously described POB attenuation injection can only operate on spatial patterns on horizontal lines.

[0038] Using the lithography apparatus LA according to this disclosure, the pupil can be adjusted in the scanning direction of the irradiation area IR, which can adjust the irradiation mode in the scanning direction. This can be achieved by utilizing the pupil tuning capability of a suitable configurable irradiation module (e.g., a MEMS irradiator) to divide the angular distribution of the exposure field (irradiation area IR) in the scanning direction (i.e., the y-direction) into, for example, a first angular distribution and a second angular distribution.

[0039] During exposure, a first angular distribution corresponding to a first portion of the irradiated region IR and a second angular distribution corresponding to a second portion of the irradiated region IR can spatially overlap in a transition region or transition zone. The transition zone can correspond to the middle or central portion of the irradiated region IR.

[0040] The first and second angular distributions can be complementary. That is, the first angular distribution can include a first peripheral region of a full-angle distribution defined by the numerical aperture of the illuminator, and the second angular distribution can include a second peripheral region of a full-angle distribution. The first and second peripheral regions can be mirror-symmetrically located within the full-angle distribution (commonly referred to as the pupil plane of the illuminator optics). For example, the first and second angular distributions can include corresponding monopoles of opposite poles; for example, the first angular distribution can include a monopole with a north pole, and the second angular distribution can include a monopole with a south pole. Thus, the transition region can include a y-dipole, i.e., a complementary monopole, formed by the overlap of the first and second angular distributions. Advantageously, this method can allow for dual monopoles in a single exposure, which can improve throughput. A y-dipole transition example may be beneficial when writing a horizontal spatial pattern.

[0041] The complementary bimonopole angular distribution with y-dipole transitions described above is a non-limiting example. The complementary bimonopole angular distribution can have, for example, an x-dipole transition region, which is advantageous for writing vertical linear spatial patterns. In some cases, the complementary distribution can be a rotating bimonopole, which is advantageous for writing rotating line spacing. In some cases, the method can be extended to angular distributions corresponding to multipole types, such as quasar and hexapole angular distributions. In this case, the slit or illumination region IR can be divided into multiple regions, i.e., at least two regions corresponding to different magnetic poles.

[0042] Advantageously, the transition zone or transition area where both the first and second angular distributions exist can be used for alignment purposes, such as mask alignment.

[0043] In some examples, a linear gradient of the POB (as described in WO2023104419A1) can be used to compensate for the offset between a spatial image of a first angular distribution and a spatial image of a second angular distribution at the wafer level, for example, to compensate for the displacement of the spatial image as the mask stage tilts. This can improve contrast loss due to mask-induced attenuation (M3D effect) and increase the overlap process window (OPW). In some cases, system drift (e.g., due to thermal effects) causes variations in projection lens aberrations. Transition regions can be used to facilitate aberration drift measurements and thus facilitate the correction of said aberrations.

[0044] In some embodiments, the irradiation system IL of the lithography apparatus includes a first optical element, and the angular distribution of radiation at the irradiation region IR depends on the spatial distribution of radiation received by the first optical element. However, the first optical element is not disposed in the entrance pupil of the projection system PS or in a plane conjugate thereto. The first optical element may be the faceted pupil reflector device 11 described above.

[0045] The angular distribution of radiation at the irradiated region IR depends on the spatial distribution of radiation received by the first optical element 11. However, the first optical element 11 is not positioned within or in the plane conjugate of the entrance pupil of the projection system PS. This means that the entrance pupil of the projection system PS projects onto the first optical element 11 via each point of the irradiated region IR, typically mapping onto different portions of the first optical element 11. The inventors have recognized that this allows the first optical element 11 to be irradiated in order to create different irradiation patterns for different portions of the irradiated region IR.

[0046] exist Figure 3a and 3b A simplified schematic diagram of a first optical element 11 is shown. The first optical element 11 includes a mirror array comprising an array of individually movable mirror facets (denoted as circles). The mirror array 11 is arranged to receive radiation and guide at least a portion of the received radiation to an illumination region IR. Some individual facets receive radiation (from a second optical element 10) and are represented by shaded circles, while some individual facets do not receive radiation and are represented by hollow circles. The angular distribution of radiation at the illumination region IR depends on which mirror facet in the array of individually movable mirror facets receives radiation. Figure 3a and 3b The diagram also shows the first position in the irradiated area IR (see...). Figure 3a ) and the second position in the irradiated area IR (see Figure 3b The projection 30 (represented by the dashed line) of the entrance pupil of the projection system PS onto the first optical element 11. For a given position in the illumination area IR, the pupil or illumination pattern is the projection of the entrance pupil onto the first optical element 11. The first position in the illumination area IR (e.g., ...) is used for this purpose. Figure 3a The illumination pattern 32 (i.e., the overlap between the projection 30 and the first optical element 11) shown in the image is in... Figure 4a The diagram shows the second position (e.g., in the irradiation region IR) used for illumination. Figure 3b Irradiation mode 34 (as shown) in Figure 4b As shown in the image.

[0047] It should be understood that, since the first optical element 11 is not located in or in the plane conjugate of the entrance pupil of the projection system PS, the projection 30 of the entrance pupil of the projection system PS onto the mirror array 11 via each point of the illumination area IR is typically mapped onto different parts of the mirror array (and thus onto a different set of individual movable mirror facets).

[0048] Because the first optical element 11 is positioned within the entrance pupil of the projection system PS or in a plane conjugate thereto, the pupil will change with the illumination area IR when observed through the illumination region IR. For example, from Figure 3a and 3b It can be seen that the "spots" of light from the individual mirror facets (i.e., shadow circles) being illuminated will appear to move or jump in the pupil plane as a function of their position in the illumination area IR. Advantageously, this allows for some control over the angular distribution received in the illumination area IR.

[0049] In some embodiments, each individually movable mirror facet of the first optical element 11 comprises a microelectromechanical system (MEMS) micromirror. Therefore, for such an embodiment, the first optical element 11 can be considered to comprise a MEMS micromirror array.

[0050] In some embodiments, the irradiation region IR comprises multiple portions, and the irradiation system IL is configured to control the received radiation such that portions of the received radiation directed to different portions of the irradiation region IR have different angular distributions, as now referenced. Figure 5 and 6 The discussion focuses on the use of different illumination modes for different portions of the illumination region IR. For scanning lithography equipment (also known as a scanner), different portions of the illumination region IR can correspond to different positions along the scanning direction (which can be the y-direction) of the illumination region IR.

[0051] As mentioned above, refer to Figure 1 In some embodiments, the irradiation system IL further includes a second optical element 10, which is arranged to receive radiation from the radiation source SO and guide at least a portion of the received radiation to the first optical element 11. The second optical element may be the faceted field reflector device 10 described above.

[0052] The second optical element 10 may include a second mirror array comprising a two-dimensional array of individually movable mirror facets. In some embodiments, each individually movable mirror facet of the second optical element 10 comprises a microelectromechanical system (MEMS) micromirror. Therefore, the second optical element 10 can be considered to comprise a MEMS micromirror array. The faceted field mirror assembly 10 may include approximately 100,000 individually movable reflective optical elements. These reflective optical elements may substantially cover portions 24, 26 of the faceted field mirror assembly 10 that receive radiation from the radiation source SO (see...). Figure 2a (and related discussions). In some embodiments, any gap between adjacent reflective optical elements may be minimal.

[0053] In some embodiments, a two-dimensional array of independently movable reflective optical elements disposed on the faceted field mirror assembly 10 can be considered to include multiple sets of reflective optical elements. Each set of reflective optical elements may include multiple adjacent independently movable reflective optical elements on the faceted field mirror assembly 10. Each set of reflective optical elements in the multiple sets of reflective optical elements may be referred to as a cluster of reflective optical elements.

[0054] For reference now Figure 5 and 6 The individual movable mirror facets of the two-dimensional array discussed can be arranged differently from each other.

[0055] like Figure 5 As illustrated very schematically in embodiments of this disclosure, the second optical element 10 may include different portions 36, 38, which may have different sizes and / or shapes and may be imaged onto different portions 40, 42 of the illumination region IR. This contrasts with known arrangements in which the second optical element 10 includes multiple identical surfaces (or sets of MEMS mirrors forming identical virtual surfaces) entirely imaged onto the entire illumination region IR.

[0056] Each of the multiple different portions 36, 38 can be considered as a focusing element with optical power. Each of the multiple focusing elements 36, 38 can, for example, be arranged to form an image of the intermediate focus 6 (i.e., the virtual radiation source) at or near the first optical element 11 (i.e., the pupil faceted mirror).

[0057] For example, in some embodiments, each of the focusing elements 36, 38 may include a concave mirror (e.g., as described above). Figure 1 (One of the field-faceted reflectors described).

[0058] Alternatively, each of the multiple focusing elements 36, 38 may comprise a group or cluster of individually movable mirror facets of a two-dimensional array. For example, each focusing element may comprise a cluster of (typically flat) mirror facets (e.g., MEMS mirrors) arranged to collectively form a concave mirror.

[0059] Note that, in order to ensure the uniformity of the spatial distribution of radiation on the irradiation area IR (which is important for dose control), each location in the irradiation area IR can receive radiation from multiple focusing elements 36, 38 (although for ease of understanding, in...). Figure 5 Only two focusing elements are shown, but it should be understood that in practice, there could be 100 or 1000 focusing elements on the second optical element 10. However, in embodiments of this disclosure, typically, each location in the illumination area IR does not receive radiation from all the focusing elements 36, 38, compared to known arrangements.

[0060] Depend on Figure 5 The radiation guided by the two focusing elements 36 and 38 shown partially overlaps spatially at the irradiation region IR. However, in embodiments of this disclosure, compared to known arrangements, the radiation guided by the two different focusing elements typically does not substantially cover the irradiation region IR, and an adjustable overlap may exist between the radiation guided by the two different focusing elements at the irradiation region IR.

[0061] In some embodiments of this disclosure, the second optical element may include multiple sets of focusing elements. Each set of focusing elements may be arranged to direct radiation to different portions of a plurality of sections of the illumination region IR. Radiation directed by two focusing elements from a given set may spatially overlap at the illumination region IR and may fill corresponding portions of the illumination region IR. Radiation directed by two focusing elements from different sets may have adjustable spatial overlap at the illumination region IR. Referring now to Figure 6 Discuss examples of this arrangement.

[0062] exist Figure 6 In the example shown, the second optical element 10 includes two focusing elements 44 and 46. The first focusing element 44 is arranged to direct radiation to a first portion 48 of the illumination region IR. The second set of focusing elements 46 is arranged to direct radiation to a second portion 50 of the illumination region IR. The radiation directed by the two focusing elements spatially overlaps at the illumination region IR and can fill the corresponding portions (48 or 50) of the illumination region IR.

[0063] It should be understood that, although the focusing elements 44, 46 and the irradiation area IR are in Figure 6 The image is shown as a roughly rectangular shape, but this is merely for ease of understanding the new arrangement of focusing elements 44 and 46. In reality, the illumination area IR can be matched to the incident aperture of the projection system PS, and for example, could be... Figure 2b As shown and in the above forms.

[0064] The first and second optical components 10, 11 are arranged to form an image of each of the focusing elements 44, 46 in corresponding portions 48, 50 of the illumination region IR. All these images from a given group are spatially superimposed at the illumination region IR.

[0065] Each focusing element in the focusing element can have substantially the same size and shape (which can be imaged onto the corresponding portions 48, 50 of the irradiated area IR).

[0066] Each focusing element guides radiation via a different portion of the first optical element. For example, focusing element 44 guides radiation to a first portion 48 of the illumination region IR via portion 52 of the first optical element 11. Similarly, focusing element 46 guides radiation to a second portion 50 of the illumination region IR via portion 54 of the first optical element 11. In this way, the radiation beam is guided to the patterning device such that at least two different portions of the patterning device (different in position at least along the scanning direction of the illumination region) receive radiation from different regions of the irradiator optics (i.e., focusing elements 44 and 46) within the pupil plane associated with the irradiator optics.

[0067] Figure 7 The diagram illustrates the pupils 56 and 58, or illumination patterns, of two different portions 48 and 50 of the illumination region IR. In this example, the pupil 56 of the first portion 48 of the illumination region IR is a monopole including the South Pole, and the pupil 58 of the second portion 50 of the illumination region IR is a monopole including the North Pole.

[0068] exist Figure 6 In the example shown, the illumination system IL (which includes a first optical element 11 and a second optical element 10) is configured to control radiation (received from a radiation source SO and directed to a patterning device MA) such that radiation with a first angular distribution 56 is received at a first portion 48 of the illumination region IR, and radiation with a second angular distribution 58 is received at a second portion 50 of the illumination region IR, each angular distribution corresponding to a different region of the illuminating optical pupil plane. Specifically, one end of the illumination region IR (e.g., in the scanning direction y) may receive radiation with the first angular distribution 56, and the other end of the illumination region IR may receive radiation with the second angular distribution 58.

[0069] exist Figure 6 In the example shown, the first angular distribution 56 and the second angular distribution 58 may overlap in the illumination region IR, which corresponds to the center (i.e., the middle) of the slit in the third portion of the IR transition region 57. In this example, because the first angular distribution 56 and the second angular distribution 58 include complementary monopoles (i.e., north and south poles), the transition region 57 may include a y-dipole.

[0070] The transition region 57 can be adjustable, for example, by selecting (in the case of actuable elements 44 and / or 46) a specific set of pupil facets 54 and 56. Advantageously, the transition region 57 can be tuned for a specific purpose. During monopole exposure, stage alignment or projection lens-related measurements may become sensitive to focal point changes due to the inherent non-telecentricity of the monopole (i.e., the centroid of the angular distribution is significantly offset from the optical axis of the illuminator). A monopole can concentrate light on one side of the pupil, which may not be optimal for wavefront measurements requiring a uniformly filled pupil. In some cases, diffusers (e.g., on reference marks) have been used to homogenize the pupil with limited success. Therefore, monopole exposure can result in high gradients in the pupil, which can adversely affect wavefront measurements. Therefore, the transition region can be configured, for example, with a dipole to facilitate stage alignment operations and wavefront measurements.

[0071] In the example, the alignment of the spatial image associated with the features of the patterning device can depend on the coordinates of the radiation beam in the pupil plane associated with the irradiator optics. In some cases, such as due to the M3D effect, the spatial image may be misaligned at the wafer level. That is, due to attenuation effects, the north and south poles of the dipole illumination may be displaced on the wafer in the X direction. According to aspects of this disclosure, a method can be provided to correct the displacement by providing radiation having a first angular distribution and a second angular distribution to counteract the displacement. The displacement may be associated with a difference between portions of the irradiated area. The correction may be based on projection lens configuration or focus adjustment.

[0072] In some examples, the first angular distribution and the second angular distribution correspond to a monopole, wherein the full angular distribution is a y-dipole, and wherein the features to be illuminated on the patterning device include vertical lines.

[0073] In some examples, the first angular distribution and the second angular distribution correspond to a monopole, wherein the full angular distribution is an x-dipole, and wherein the features to be illuminated on the patterning device include horizontal lines.

[0074] exist Figure 8 In the example shown, the first optical component 11 includes four focusing elements 44, 45, 46, and 47, which are arranged to guide radiation to the illumination region IR via portions 52, 53, 54, and 55 of the first optical element 11, to form an image of each focusing element 44, 45, 46, and 47 in corresponding portions of the illumination region IR. In this example, the angular distributions 56, 58, 60, and 62 vary in the scanning (i.e., Y) and non-scanning (i.e., X) directions. In other examples not shown, the illumination region IR can be illuminated in either the scanning or non-scanning directions using radiation with any number of varying angular distributions in corresponding portions of the illumination region IR, depending on the needs of any particular use case.

[0075] In some cases, imaging improvement processes (e.g., overlay optimization) can be implemented where the interaction between pupil non-telecentricity and focus error during scanning can lead to overlay errors on the wafer. For example, inherently non-telecentric monopolar illumination can be co-optimized with focus control (i.e., focus variation during scanning) to apply a pattern shift that can offset existing overlay errors or anticipate predicted overlay errors. In contrast to the contrast enhancement operations described above, overlay improvement operations may be more favorable to telecentric illumination during scanning. Therefore, the illumination area IR can be adjusted to balance contrast gain and minimizing overlay errors. That is, the illumination area IR, or its control, becomes a control knob for correcting overlay errors. The entire illumination area IR can be tunable to benefit any particular use case. For example, when stitching two fields, tuning the pupil at the periphery of the illumination area to be stitched may be beneficial.

[0076] In some cases, such as depending on the pattern to be written, providing an asymmetric angular distribution (i.e., in the irradiated area IR along the scanning direction) can be beneficial. For example, the intensity effect caused by M3D can be minimized by having asymmetric exposure conditions, such as a pupil shape varying along the scanning direction in the irradiated area. For a particular type of feature (e.g., horizontal or vertical line spacing), the intensity of the first angular distribution can differ from the intensity of one or more second angular distributions to address the intensity effect caused by M3D. That is, when one end of the irradiated area IR is irradiated independently of the other end of the irradiated area IR at least in the scanning direction (e.g., using a monopole), there may be some periodicity during scanning.

[0077] Due to the reflective nature of EUV masks, they are illuminated with EUV radiation at a 6-degree object principal ray angle (CRAO). The azimuth angle of the EUV radiation principal ray can follow the curvature of the slit or the irradiated area IR, which can cause a variation in the radiation angle at the end of the irradiated area IR by + / - 6 degrees, resulting in wafer-level pattern shift. Furthermore, EUV masks can have angle-dependent reflectivity. That is, changing the incident angle of radiation on the mask can lead to different reflectivities, which can cause the M3D effect, resulting in further pattern shift. Besides the reflective asymmetry of EUV masks, the degree of variation in the radiation angle caused by the curvature of the irradiated area IR can be due to non-centrocentricity (i.e., the center of the angular distribution may deviate from the optical axis of the irradiator). For example, a negative centrocentric shift can exist at one end of the irradiated area IR, while a positive centrocentric shift can exist at the opposite end, which can lead to pattern shift and contrast loss. To counteract the non-centrocentricity, a method can be provided comprising: determining a pattern offset or a predicted pattern offset on a wafer based on the principal ray angle and the principal ray azimuth angle at the object; and determining an angular distribution of radiation in an irradiated region IR based on the pattern offset or the predicted pattern offset, wherein the angular distribution in the irradiated region IR varies at least along the scanning direction of the irradiated region IR. In a purely exemplary angular distribution, the irradiated region IR may include a first monopole and a second monopole distributed along the scanning direction of the irradiated region IR, wherein the first monopole may include a first irradiation intensity, and the second monopole may include a second irradiation intensity different from the first irradiation intensity. The first and second irradiation intensities may be determined based on the principal ray angle and the principal ray azimuth angle at the object.

[0078] Figure 7 A graph showing the illumination intensity (I) versus the IR length of the irradiated region in the scan direction (y) for an exemplary complementary dual monopole exposure is presented. Complementary monopole regions 56 and 58, and a dipole transition region 57 can be observed. The transition region 57 can be adjusted for different applications.

[0079] In some cases, it is not possible to optimize exposure for all operations (e.g., mask alignment, wavefront correction, imaging enhancement, and overlay enhancement). For example, overlay enhancement may require scanning to change telecentrism, but contrast enhancement requires scanning to change non-telecentrism (i.e., pole division). In such cases, exposure can be co-optimized (i.e., by the angular distribution of the IR of the irradiated area) to provide the best-case scenario. This co-optimization can co-optimize, for example, imaging or placement metrics (e.g., overlay or edge placement error) and contrast. Some optimization processes are described below and can be based on, for example, wafer focus control, the type of layer being printed, and / or edge placement error (EPE) formulas. The optimization processes can also be applied, for example, to optimize POB attenuation injection. Another co-optimization method suitable for or applicable to this application is described in US2022 / 0334499A1, which is incorporated herein by reference.

[0080] It is known that scanners may include components that may degrade throughout the lifetime of the component or scanner. In cases of component degradation, it may be difficult to consistently repeat the same exposures and irradiations to replicate a specific pattern on the wafer. That is, the expected pupil may change over time, which could be a cause of variations in the system fingerprint. In other cases, using conventional tools (i.e., conventional scanners) in conjunction with existing technology scanners during multi-tool exposure can lead to exposure or irradiation mismatches (also known as tool-to-tool matching), for example, due to component degradation over time (e.g., in the collector or irradiator) or differences in manufacturing and / or setup tolerances. This can result in pupil mismatch between tools, which can adversely affect, for example, overlay performance across tool lifetimes or between tools, and thus critical dimension performance. To mitigate these problems, a method can be provided to match a first angular distribution with a second angular distribution. A first angular distribution (e.g., as provided by a first tool) can be determined and used as a baseline angular distribution. A second angular distribution (e.g., from a second tool, or from the first tool at different time points) can be determined and optimized based on the first angular distribution. This is achieved by modifying the second angular distribution in the irradiated area IR, at least in the non-scanning direction (e.g., by using the irradiation system IL currently described, which includes first and second optical elements 11, 10), to minimize the difference between the first and second angular distributions. The second angular distribution can be optimized based on selected critical size features on the target. Thus, pupil variation can be minimized (e.g., as a result of part degradation or tool-to-tool matching).

[0081] In some cases, the M3D effect can cause non-uniform exposure of the field (i.e., the exposure field of the wafer) toward the edge or margin of the wafer, which can lead to diagonal CD fingerprint variations relative to the scanning (i.e., Y) and non-scanning (i.e., X) directions. According to aspects of this disclosure, a method for providing uniform exposure can be provided, comprising: determining an exposure non-uniformity or a predicted non-uniformity; and determining an angular distribution of radiation in an irradiated region IR based on the non-uniformity or the predicted non-uniformity, the angular distribution varying at least in the scanning direction. In some cases, the angular distribution may be fixed or constant in the non-scanning direction (i.e., X), and the angular distribution may be different, or dynamically varied in the scanning direction (i.e., Y) based on the determined or predicted non-uniformity. Thus, for example, diagonal CD fingerprint variations can be minimized.

[0082] In some cases, such as those described in WO2023104419A1, known overlay correction (i.e., POB attenuation) methods may include, for example, tilting the mask and / or wafer stage or configuring a projection lens to modify the angular distribution of radiation included in the illumination region IR. In a particular example, processes involving wafer bonding can cause wafer deformation that may lead to overlay errors. Known correction methods may include configuring a projection lens to modify the angular distribution of radiation included in the illumination region IR, as represented by one or more Zernike functions (e.g., Z2, also known as Z2 injection, which may correspond to image displacement in the x-direction). In some cases, POB attenuation injection may lead to further attenuation errors. For example, Z2 injection may result in Z3 attenuation errors, which may correspond to y-displacement of imaging features that cause contrast loss. This attenuation may affect the CD and contrast performance of horizontal and 2D features.

[0083] According to various aspects of this disclosure, a method can be provided to mitigate errors caused by overlay correction by providing radiation with an angular distribution (e.g., using the currently described illumination system IL comprising first and second optical elements 11, 10), the angular distribution corresponding to a telecentric offset in the illumination region IR at least in the scanning direction. The angular distribution can be determined based on the error introduced by the overlay correction. In some examples, the error can be an image offset. In the example above, where the Z3 attenuation error is introduced by the overlay correction, the angular distribution can be determined based on a y-displacement of an image feature or a predicted y-displacement of an image feature, where the angular distribution can correspond to a telecentric y-offset in the illumination region IR. In some cases, the method may further include tilting the wafer stage to provide a linear focus profile by scanning. That is, providing radiation with an angular distribution that corresponds to a telecentric offset in the illumination region IR can result in further attenuation errors in the z-direction. Therefore, a telecentric offset can be determined to optimally counteract the error caused by the overlay correction, and the wafer stage tilt can be determined accordingly to provide optimal focus by scanning. Alternatively, the stage tilt can be determined based on focus-sensitive features on the wafer to provide optimal focus through scanning, and the telecentric offset can then be determined based on errors caused by overlay correction. In some examples, the amount of stage tilt (i.e., overlay) and telecentric offset is optimized to find a balance between optimal overlay performance and optimal focus performance.

[0084] Figure 9 a illustrates an example of how non-telecentric illumination 901 (non-telecentric relative to optical axis 915) combined with a focus offset 903 relative to focal plane 904 (e.g., due to projection lens modification) can cause a field position-dependent pattern offset 902. By configuring non-telecentricity and focus offset in the exposure field, the pattern offset can be configured, for example, to counteract existing overlay errors. Figure 9 b illustrates an example of how, according to various aspects of this disclosure, a reduced overlay error 905 can be achieved through a combination of non-telecentric illumination 901 provided by pupil variation (i.e., angular distribution corresponding to telecentric offset) and focal offset variation 903 provided by wafer stage tilt. That is, by utilizing a combination of non-telecentric illumination 901 and appropriately selected focal offset / tilt 903, a reduced overlay error (i.e., ...) can be provided relative to existing overlay errors (not shown). Figure 9 (See solid black arrow 905 shown in b). Edge roll-off correction

[0085] In another example, the object of the present invention is to configure illumination 901 to mitigate pattern placement error (PPE) associated with substrate unevenness that causes overlay errors. Substrate (wafer) unevenness can be, for example, caused by the fact that the wafer is uneven and less effectively clamped to the substrate stage at edge regions, a so-called edge roll-off (ERO). This results in a locally tilted wafer surface at the edge regions of the wafer. In the case of telecentric illumination of the wafer edge regions (e.g., targeting a patterned flat wafer), the local tilt causes local PPE (overlay error) because the wafer surface does not coincide with the assumed flat wafer plane perpendicular to the optical axis of the optics. To counteract the PPE caused by ERO, illumination 901 can be configured to have a non-telecentric variation that counteracts the overlay error variation associated with ERO on the edge regions. Overlay correction is proposed to be achieved by applying a pupil variation on one or more portions of one or more illumination regions within the wafer edge regions. In one embodiment, the pupil variation can cause a non-telecentric condition that is expected to result in an image offset (variation) in the XY plane of the wafer (associated with PPE) due to the local wafer tilt (variation). Figure 10 The principle of overlay error correction is described. In the first scenario (Scenario 1), a flat area of ​​wafer 1030 is patterned by imaging pattern 1020 using telecentric illumination mode 1010. In Scenario 2, the same telecentric illumination mode is used to pattern a (locally) tilted wafer region 1031. Due to the tilted surface, pattern 1020 will not coincide with the intended pattern placement 1021 (depicted by a gray box), thus introducing pattern offset that leads to overlay error. Scenario 3 describes a situation where an intentional amount of non-telecentricity is introduced by patterning the tilted wafer region 1031 using non-telecentric illumination mode 1011. Pattern 1022 now again coincides with its intended pattern placement 1021, thus at least reducing pattern placement error and therefore reducing potential overlay error.

[0086] Empirically, the required non-centrocentricity equals the overlay error divided by the focal change that causes the overlay error. The overlay error caused by the tilted wafer surface 1031 can be calculated by multiplying the wafer surface tilt by half the wafer thickness. Reduce attenuation by changing the shape of the pupil.

[0087] As explained in the previous section of this document, the so-called mask 3D effect can cause scan position-dependent image shift (attenuation), which manifests as a loss of image contrast. In addition to the mask 3D effect, variations in projective optical aberrations along the scan direction can also cause this attenuation and thus affect image contrast. It has been found that at least a portion of the attenuation caused by aberrations can be counteracted by configuring illumination pupils at different portions of the illumination area along the scan direction. Figure 11An example is described where a hexapolar illumination pupil 1100 is divided into a first tripolar 1110 associated with a first portion of the illumination region and a second tripolar 1120 associated with a second portion of the illumination region, wherein the first and second illumination regions are separated in the scanning direction “slit-Y”. A dual tripolar configuration is found (use case 2). Figure 11 The “UC2” in the text and the six-polar pupil (use case 1; Figure 11 In the context of "UC1", if the aberration level is 1 nm / mm tilted for coma (Zenick 5 and / or 6), the contrast loss due to aberration ranges from 9% to 2%, such as... Figure 11 The dashed line in the figure represents the Zernike coefficient as a function of the slit-Y coordinate (e.g., along the scanning direction). Aberration control-induced attenuation

[0088] In some cases, attenuation caused by the mask 3D effect can be at least partially corrected by inducing a change in the projection optical aberration along the scanning direction to counteract it. This can be further improved by selecting appropriate variations in the illumination pupils at different portions of the illumination area along the scanning direction. For example, it has been found that for each corresponding portion of the illumination area, the previously discussed hexapolar illumination configuration can be divided into three dipole pupils (each with a different orientation), while simultaneously injecting a linear variation of the Z5 aberration at said portion of the illumination area along the scanning direction. Figure 12 The diagram depicts the decomposition of the hexapolar 1200 into three dipoles, each dipole being associated with a different irradiation region oriented along the scanning direction “slit-Y”. The dipole configurations for each dipole are dipole-X 1210, dipole-X 1220 rotated by 60 degrees, or dipole-X 1230 rotated by 120 degrees. Improved Z-contour resist through dynamic pupil shape control

[0089] To date, the purpose of varying the illumination pupil along the scanning direction has been to counteract or induce spatial image offset variations within the substrate plane (e.g., associated with PPE / overlay errors). However, the described pupil shape control method can also be used to control the focal position of the spatial image during the scanning direction in order to homogenize the spatial image through the resist stack. In one embodiment, different portions of the illumination region have different illumination pupils (e.g., including different monopoles within a dipole or quadrupole shape), such that each portion (each portion separated in the scanning direction) is associated with a different focal position of the spatial image. Optionally, the projection optics can be configured to further inject a focal point (Z4) tilted along the scanning direction to further homogenize the spatial image along the resist stack. Attenuation reduction based on double exposure using different areas on the mask or different masks

[0090] In another embodiment, it can be decided not to apply a position-dependent illumination pupil during the scanning operation, but instead to perform a double-exposure type scanning operation using two different pupil shapes and a positional offset between the scanning exposures to address pupil shape-dependent image offsets (leading to attenuation). When a suitable set of pupil shapes and a carefully chosen positional offset are selected, this method can achieve a similar reduction in attenuation caused by mask 3D effects. A drawback of this method is that the chosen positional offset may only be suitable for a narrow range of features on the mask; for example, features with small pitch may require a larger positional offset than features with small pitch, and vice versa. This drawback is proposed to be overcome by using any of the methods mentioned below:

[0091] 1) As described above, the scanning exposure is divided into two exposures, but each exposure uses a different mask (“intermediate mask”). Each mask is configured to be illuminated with its corresponding pupil shape and is further configured to apply different positional offsets to different features (e.g., different spacings) such that each feature receives the optimal positional offset between the different exposures.

[0092] 2) As described above, the scanning exposure is divided into two exposures, but instead of different masks, different regions of the mask ("intermediate mask") are used for each exposure. Each region is configured to be illuminated with its corresponding pupil shape and is further configured to apply different position offsets (e.g., different pitches) to different features, such that each feature receives the optimal position offset between the different exposures.

[0093] It has been found that when the proposed method is used to apply feature-specific positional offsets between exposures, a 17% better image log slope (ILS) can be obtained compared to dual monopole exposures based on a single mask / single mask region configuration, in the case of L / S gratings spanning a pitch range of 28–150 nm.

[0094] In one embodiment, a method of configuring a lithography apparatus is provided, the lithography apparatus including an irradiator optics for guiding at least a portion of a radiation beam to an irradiation region of a patterning apparatus to impart a pattern to the radiation beam and form a patterned radiation beam, the method comprising: configuring the irradiator optics such that at least two distinct portions of the patterning apparatus receive radiation from different regions within a pupil plane associated with the irradiator optics, the at least two distinct portions being different at least in position along a scanning direction of the irradiation region, wherein each of the distinct portions includes a plurality of features positioned such that when the lithography apparatus is used in a dual-exposure setup to provide the distinct portions to the same region on the substrate, the corresponding positions of each of the plurality of features on the substrate are nominally equal between the distinct portions.

[0095] In one embodiment, multiple features are lines and spacing (L / S) with different pitches.

[0096] In one embodiment, different regions within the pupil plane are associated with different poles of the dipole pupil shape. Pattern displacement caused by mask bias and methods to reduce pattern displacement

[0097] In some cases, patterning devices can be optimized to create patterns of mask features by applying a so-called (mask) bias to the dimensions (height and / or width) of one or more portions of the absorbing material provided to a reflective or transmissive substrate. For example, the absorbing material can be tantalum (Ta). For instance, in low-n mask structures, spatial image contrast can be enhanced by tuning the bias (in this case, the absorber height) to optimize the amplitude of the diffraction orders. However, the phase between diffraction orders can also change, thus causing a shift in the lateral position of the spatial image between monopoles, for example, of a chosen pupil shape. However, the shift between monopoles can be corrected using the methods mentioned above, for example, by configuring the irradiator optics such that at least two different portions of the patterning device receive radiation from different regions within the pupil plane associated with the irradiator optics, said at least two different portions differing in position at least along the scanning direction of said irradiation region. The latter is typically combined with corrections using distortion mechanisms to bring the spatial image associated with the different regions within the pupil plane to a desired (“nominal”) position, for example, by introducing a specific aberration fingerprint along the scanning direction based on one or more manipulators of the projection optics using a photolithography apparatus.

[0098] Therefore, by using a method that provides different pupil shapes for different parts of the patterning device, a significant contrast enhancement of the spatial image is facilitated by allowing stronger mask bias, resulting in greater contrast enhancement while offsetting the side effects of extremely specific spatial image displacement.

[0099] Another advantage is that the same absorber height can be used for multiple features on the patterning device, such as horizontal (H) and vertical (V) features. This allows a single patterning device to be used for exposure of H and V features, but spatial image contrast is still optimized.

[0100] Other embodiments of the present invention are disclosed in the following list of numbered clauses: 1. A method of configuring a photolithography apparatus, the photolithography apparatus including an irradiator optics for guiding at least a portion of a radiation beam to an irradiation region of a patterning apparatus to impart a pattern to the radiation beam and form a patterned radiation beam, the method comprising: configuring the irradiator optics such that at least two different portions of the patterning apparatus receive radiation from different regions within a pupil plane associated with the irradiator optics, the at least two different portions being different at least in position along a scanning direction of the irradiation region. 2. The method according to Clause 1 further includes: receiving radiation having a first angular distribution at a first portion of the irradiation area and receiving radiation having a second angular distribution at a second portion of the irradiation area; wherein the first portion and the second portion are separated in the scanning direction. 3. The method according to Clause 2 further includes: receiving radiation such that the first angular distribution and the second angular distribution overlap at a third portion of the irradiated area. 4. The method according to Clause 3, wherein the angle distribution and area at the third portion are adjustable based on the adjustment of the first angle distribution and / or the second angle distribution. 5. The method according to any one of Clauses 3 or 4 further includes using the third portion of the irradiation area to measure at least one of the following: mask alignment, optical aberrations related to projection optics used to image the patterning apparatus onto a target portion of the substrate, or for imaging improvement. 6. The method according to any one of clauses 2 to 5, wherein the alignment of the spatial image associated with the features on the patterning device depends on the coordinates of the radiation beam in the pupil plane, and the method further includes correcting for spatial image displacement associated with differences between said portions of the irradiated area. 7. The method according to Clause 6, wherein the correction is based on at least one of focus adjustment or projection lens configuration. 8. The method according to Clause 6 or Clause 7, wherein the spatial alignment displacement is caused by the mask 3D effect. 9. The method according to any one of clauses 2 to 8, wherein the first angular distribution relates to a first peripheral region of the full angular distribution defined by the numerical aperture of the portion capturing the radiation beam, and the second angular distribution relates to a second peripheral region of the full angular distribution, the first peripheral region and the second peripheral region being symmetrically positioned in the full angular distribution endoscopic mirror. 10. The method according to any one of the preceding clauses further includes optimizing the different angular distributions based on a trade-off of at least two of the following: mask alignment, optical aberration measurement and correction, or imaging improvement. 11. The method according to any one of the preceding clauses includes optimizing different angular distributions and their areas in the scan partition based on a trade-off between at least layout metrics and contrast metrics. 12. The method according to any one of Clauses 10 or 11, wherein the optimization is performed using at least one of source mask optimization, optical proximity correction, or cost function reduction. 13. The method according to any one of the preceding clauses, wherein the irradiation area includes a unique area of ​​the patterning device that is irradiated by at least a portion of the radiation beam at any given time. 14. The method according to any one of the preceding clauses, wherein the first angular distribution and the second angular distribution correspond to a monopole, wherein the full angular distribution is a y-dipole, and wherein the feature to be irradiated on the patterning device includes a vertical line. 15. The method according to any one of clauses 1 to 13, wherein the first angular distribution and the second angular distribution correspond to a monopole, wherein the full angular distribution is an x-dipole, and wherein the irradiated feature on the patterning device includes a horizontal line. 16. The method according to any one of clauses 1 to 15 further comprises: receiving radiation at a plurality of portions of the irradiation area, each portion corresponding to an angular distribution of radiation different from the other portions, wherein the plurality of portions are separated in scanning and non-scanning directions. 17. The method according to any one of Clauses 1 to 15, further comprising: determining a first full-angle distribution of radiation at the patterning device; determining a second full-angle distribution of radiation at the patterning device; and modifying the second angular distribution based on the first full-angle distribution to minimize the difference between the first angular distribution and the second angular distribution, wherein the second full-angle distribution differs at least at a position along the scanning direction of the irradiation area. 18. The method according to any one of clauses 1 to 15, further comprising: determining an incident angle of radiation corresponding to at least a portion of the irradiation region; projecting a patterned radiation beam onto a target region of a substrate; determining or predicting a pattern offset on a horizontal plane of the substrate based on the incident angle of radiation; and determining an angular distribution of radiation in the irradiation region based on the determined or predicted pattern offset, wherein the angular distribution differs at least at a position along a scanning direction of the irradiation region. 19. The method according to Clause 18, wherein the angular distribution of radiation in the irradiated area comprises a first monopole and a second monopole, wherein the first monopole comprises a first irradiation intensity, and wherein the second monopole comprises a second irradiation intensity different from the first irradiation intensity. 20. The method according to any one of clauses 1 to 15, further comprising: projecting a patterned radiation beam onto a target area of ​​a substrate; determining or predicting non-uniformity of exposure at the substrate level; and determining an angular distribution of radiation in the irradiated area based on the determined or predicted non-uniformity, wherein the angular distribution differs at least at positions along a scanning direction of the irradiated area. 21. The method according to Clause 20, wherein the angle distribution is constant in the non-scanning direction of the irradiation area, and wherein the angle distribution differs in the scanning direction based on the determined or predicted non-uniformity. 22. The method according to any one of clauses 1 to 15, further comprising: projecting a patterned radiation beam onto a target region of a substrate; determining or predicting an image offset at a horizontal level of the substrate; and determining an angular distribution of radiation in the irradiated region based on the determined or predicted image offset, wherein the angular distribution corresponds to a telecentric offset in the irradiated region. 23. The method according to Clause 22 further comprises: determining an optimal focus by scanning at the substrate level; and performing substrate stage tilting to provide the optimal focus by scanning. 24. The method according to Clause 23 further includes optimizing the angular distribution and optimal focus by scanning, based on a trade-off between at least overlay performance and focusing performance. 25. A method of irradiating features on a patterning apparatus, comprising: generating a radiation beam; using irradiator optics to guide at least a portion of the radiation beam to an irradiation area of ​​the patterning apparatus, thereby patterning the radiation beam and forming a patterned radiation beam; and projecting the patterned radiation beam onto a target area of ​​a substrate; wherein the angular distribution of the patterned radiation beam has spatial and / or temporal separation at least in a non-scanning direction. 26. An irradiation system for a photolithography apparatus, operable to: receive radiation and guide at least a portion of the received radiation to an irradiation region of a patterning apparatus, thereby patterning the radiation and forming a patterned radiation beam; and project the patterned radiation beam onto a target region of a substrate; wherein the irradiation system is operable to guide the radiation beam to the patterning apparatus such that at least two different portions of the patterning apparatus receive radiation with different angular distributions in a scanning direction of the irradiation region. 27. The irradiation system according to Clause 26, wherein the irradiation system is operable to control the received radiation such that a first portion of the irradiation area receives radiation having a first angular distribution and a second portion of the irradiation area receives radiation having a second angular distribution; wherein the first portion and the second portion are separated in the scanning direction. 28. The irradiation system according to Clause 27, wherein the irradiation system is further operable to control the received radiation such that the first angular distribution and the second angular distribution overlap at a third portion of the irradiated area. 29. The irradiation system according to Clause 28, wherein the irradiation system is further operable to adjust the area and angle distribution of radiation at the third portion based on the first angular distribution and the second angular distribution. 30. The irradiation system according to clauses 26 to 29, wherein the first angular distribution relates to a first peripheral region of the full angular distribution defined by the numerical aperture of the portion capturing the radiation beam, and the second angular distribution relates to a second peripheral region of the full angular distribution, the first peripheral region and the second peripheral region being symmetrically positioned in the full angular distribution endoscopic plane. 31. The illumination system according to any one of clauses 27 to 30, wherein the illumination system includes a projection system operable to correct spatial image displacement of a spatial image associated with features on the patterning device, the displacement being associated with a difference between portions of the illumination area. 32. The illumination system according to clause 31, wherein the illumination system is operable to correct the spatial displacement based on at least one of focus adjustment or projection lens configuration. 33. The illumination system according to any one of clauses 29 to 32, wherein the illumination system is also operable to use the third portion of the illumination area for at least one of: mask alignment, optical aberration measurement and correction, or imaging improvement. 34. The illumination system according to any one of Clauses 26 to 33, wherein the illumination system is also operable to optimize different angular distributions based on a trade-off of at least two of the following: mask alignment, optical aberration measurement and correction, or imaging improvement. 35. The illumination system according to Clause 34, wherein the illumination system is further operable to perform optimization using at least one of source mask optimization, optical proximity correction, or cost function reduction. 36. The irradiation system according to any one of clauses 26 to 35, wherein the irradiation system comprises: A first optical element; and wherein the different angular distributions of radiation at the irradiated area depend on the spatial distribution of radiation received by the first optical element. 37. The illumination system according to Clause 36, wherein the first optical element comprises a mirror array, the mirror array comprising an array of individually movable mirror facets, the mirror array being arranged to receive radiation and guide at least a portion of the received radiation to the illumination area; and The different angular distribution of the radiation at the irradiated area depends on which mirror facet in the array of individual movable mirror facets receives the radiation. 38. The illumination system according to any one of clauses 36 or 37, wherein the illumination system further comprises: a second optical element arranged to receive radiation from a radiation source and to direct at least a portion of the received radiation to the first optical element; wherein the second optical element comprises a second mirror array comprising a two-dimensional array of individually movable mirror facets. 39. The illumination system according to Clause 38, wherein each of the independently movable mirror facets of the first optical element and / or the second optical element comprises a microelectromechanical system micromirror. 40. The illumination system according to any one of clauses 38 or 39, wherein the second optical element comprises a plurality of focusing elements having optical power. 41. The illumination system according to Clause 40, wherein each of the plurality of focusing elements comprises a group or cluster of the individual movable mirror facets of the two-dimensional array. 42. The irradiation system according to Clause 40, wherein the second optical element comprises a plurality of focusing elements, wherein each set of focusing elements is arranged to direct radiation to a different portion of the at least two different portions of the irradiation area. 43. The irradiation system according to any one of clauses 26 to 42, operable to guide the radiation beam such that the first angular distribution and the second angular distribution are monopolar, wherein the full angular distribution is y-dipole, and wherein the feature to be irradiated on the patterning device includes vertical lines. 44. An irradiation system according to any one of clauses 26 to 42, operable to guide the radiation beam such that the first angular distribution and the second angular distribution are monopolar, wherein the full angular distribution is x-dipole, and wherein the features to be irradiated on the patterning device include horizontal lines. 45. An irradiation system according to any one of clauses 26 to 44, operable to: direct said radiation to a plurality of portions of an irradiation area, each portion corresponding to an angular distribution of radiation different from the other portions, wherein said plurality of portions are separated in scanning and non-scanning directions. 46. ​​An irradiation system according to any one of clauses 26 to 44, operable to: determine a first full-angle distribution of radiation at the patterning device; determine a second full-angle radiation distribution at the patterning device; and modify the second angular distribution based on the first full-angle distribution to minimize the difference between the first angular distribution and the second angular distribution, wherein the second full-angle distribution is modified at least at a position along the scanning direction of the irradiation area. 47. An irradiation system according to any one of clauses 26 to 46, operable to: determine an incident angle of radiation corresponding to at least a portion of the irradiation region; determine or predict a pattern offset on a substrate level based on the incident angle of radiation; and control the received radiation based on the determined or predicted pattern offset to provide an angular distribution of radiation in the irradiation region, wherein the angular distribution is different at least at a position along a scanning direction of the irradiation region. 48. The irradiation system according to Clause 47 is operable to control the received radiation such that the angular distribution of radiation in the irradiation area includes a first monopole and a second monopole, wherein the first monopole includes a first irradiation intensity, and wherein the second monopole includes a second irradiation intensity different from the first irradiation intensity. 49. An irradiation system according to any one of clauses 26 to 46, operable to: determine or predict non-uniformity of exposure at the substrate level; and control the received radiation based on the determined or predicted non-uniformity to provide an angular distribution of radiation in the irradiation region, wherein the angular distribution differs at least at positions along the scanning direction of the irradiation region. 50. The irradiation system according to Clause 49, wherein the angle distribution is constant in the non-scanning direction of the irradiation area, and wherein the angle distribution differs in the scanning direction based on the determined or predicted non-uniformity. 51. The illumination system according to clauses 26 to 46 is operable to: determine or predict an image offset at a substrate level; and control the received radiation based on the determined or predicted image offset to provide an angular distribution of radiation in the illumination region, wherein the angular distribution corresponds to a telecentric offset in the illumination region. 52. A photolithography apparatus comprising an irradiation system according to any one of clauses 26 to 51. 53. The lithography apparatus according to Clause 52, including a substrate stage, the lithography apparatus being operable to: determine an optimal focus by scanning at the substrate level; perform substrate stage tilting to provide the optimal focus by scanning; and optimize the angular distribution and optimal focus during scanning based on a trade-off between at least overlay performance and focusing performance. 54. A method for forming a pattern on a target region of a substrate, the method comprising: Generating a radiation beam; using an irradiator optics to guide at least a portion of the radiation beam to an irradiation area of ​​a patterning device, thereby patterning the radiation beam and forming a patterned radiation beam; and projecting the patterned radiation beam onto the target area of ​​the substrate; wherein the radiation beam is guided to the patterning device such that at least two different portions of the patterning device receive radiation from different areas of the irradiator optics within a pupil plane associated with the irradiator optics, the at least two different portions being different at least in position along the scanning direction of the irradiation area. 55. The method according to Clause 22, wherein the predicted image offset is associated with a local tilt of the substrate. 56. The method according to Clause 6 or Clause 7, wherein the spatial alignment displacement is caused by aberration variation along the scanning direction. 57. The method according to Clause 8 further includes inducing aberration changes along the scanning direction based on the spatial image displacement and the configuration of the illuminator optics. 58. The method according to Clause 2, wherein the focal position of the spatial image associated with a feature on the patterning device depends on the coordinates of the radiation beam in the pupil plane, and the method further comprises homogenizing the spatial image based on the difference in focal position between the portions of the irradiated area. 59. The method according to Clause 1, wherein each of the different portions comprises a plurality of features positioned such that when the lithography apparatus is used in a dual-exposure setting to provide the different portions to the same area on the substrate, the corresponding positions of each of the plurality of features on the substrate are nominally equal between the different portions. 60. The method according to Clause 6, wherein the spatial alignment displacement is caused by a bias applied to the absorber portion of the patterning device. 61. The method according to Clause 60, wherein the applied bias is configured to optimize the amplitude of the diffraction order scattered from the patterning device in order to improve the contrast of the spatial image. 62. The method of Clause 61, wherein the applied bias is an optimized absorber height (thickness). 63. The method according to Clause 62, wherein the height of the absorber is optimized for a plurality of features on the patterning device. 64. The method according to any one of clauses 60 to 63, wherein the patterning device comprises a low-n material. 65. A computer program comprising program instructions that, when run on a suitable device, are operable to perform the method of any one of clauses 1 to 25 or 54 to 64. 66. A non-transitory computer program carrier, comprising the computer program of clause 65.

[0101] It is often desirable to be able to computationally determine how the patterning process will produce the desired pattern on the substrate. For example, computational determination may include simulation and / or modeling. Models and / or simulations can be provided for one or more parts of the manufacturing process. For example, it may be desirable to simulate the photolithography process that transfers a patterning device pattern onto a resist layer of the substrate, and the pattern produced in that resist layer after resist development, simulating metrological operations such as determining overlay, and / or performing other simulations. The purpose of the simulation may be to accurately predict, for example, metric scales (e.g., overlay, critical dimensions, reconstruction of the three-dimensional profile of substrate features, the dose or focus of the photolithography equipment when printing features on the substrate with the photolithography equipment), manufacturing process parameters (e.g., edge arrangement, spatial image intensity slope, auxiliary resolution feature (SRAF), etc.), and / or other information, which can then be used to determine whether the intended or target design has been achieved. The intended design is typically defined as a pre-optical proximity-corrected design layout that can be provided in a standardized digital file format such as GDSII, OASIS, or other file formats.

[0102] Various optimization methods can be used to achieve pattern fidelity. Simulation and / or modeling can be used to determine one or more metrological metrics (e.g., performing overlay and / or other metrological measurements), configure one or more features of a patterned device pattern (e.g., performing optical proximity correction (OPC)), configure one or more features of illumination (e.g., changing one or more properties of the spatial / angular intensity distribution of illumination, such as changing the shape), configure one or more features of a projection optics (e.g., numerical aperture, etc.), and / or for other purposes. For example, such determination and / or configuration may commonly be referred to as mask optimization, source optimization, and / or projection optimization. Such optimizations can be performed individually or in different combinations. One such example is source mask optimization (SMO), which involves configuring one or more features of a patterned device pattern (e.g., OPC) and one or more features of illumination. For example, optimization can use the parametric models described herein to predict values ​​for various parameters, including images, etc.

[0103] In some embodiments, OPC is a photolithography enhancement technique used to compensate for image errors caused by diffraction or process effects. The OPC process configures the features of the pattern to correct for errors caused by light limitations (e.g., irregularities, such as linewidths narrower or wider than the design, distortions such as rounded corners, etc.). For example, the OPC process may move edges or add additional polygons to the pattern written on the mask. OPC can be implemented in various ways, such as using rule-based OPC driven by a pre-computed lookup table based on the width and spacing between features, or using a simulation model that dynamically simulates the final pattern of a given mask pattern. The aim is to reproduce the original layout drawn by the designer on the semiconductor wafer as accurately as possible.

[0104] In some embodiments, SMO is an optimization process in which one or more features of the illumination, such as source radiation intensity, pupil fill ratio (e.g., the percentage of radiation from the source passing through the pupil or aperture), amplitude and phase of the diffraction order, are optimized together with one or more features of the mask pattern (e.g., OPC).

[0105] In some embodiments, the optimization process of the system can be represented as a cost function. The optimization process may include finding a set of system parameters (design variables, process variables, check operation variables, etc.) that minimize the cost function. As used herein, the term "design variables" includes a set of parameters of a lithography projection apparatus or lithography process, such as user-adjustable parameters of the lithography projection apparatus, or image characteristics that a user can adjust by adjusting these parameters. It should be understood that any characteristic of the lithography projection process, including characteristics of the source, patterning apparatus, projection optics, or resist, can be a design variable in the optimization. Depending on the optimization objective, the cost function can have any suitable form. For example, the cost function can be the weighted root mean square (RMS) of the deviations of certain characteristics (evaluation points) of the system from expected values ​​(e.g., ideal values) of those characteristics. The cost function can typically be a nonlinear function of the design variables. Standard optimization techniques can then be used to minimize the cost function.

[0106] While this article provides specific references to the use of lithography equipment in IC manufacturing, it should be understood that the lithography equipment described herein can have other applications. Possible other applications include the fabrication of integrated optical systems, the guiding and detection of patterns in magnetic domain memory, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0107] Although embodiments of the invention may be specifically referred to herein in the context of lithography equipment, these embodiments can be used in other equipment. Embodiments of the invention can form part of mask inspection equipment, metrology equipment, or any equipment that measures or processes objects such as wafers (or other substrates) or masks (or other patterning devices). These devices are commonly referred to as lithography tools. Such lithography tools can use vacuum conditions or ambient (non-vacuum) conditions.

[0108] Where the context permits, embodiments of the present invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the present invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a machine-readable (e.g., computing device) form. For example, a machine-readable medium may include read-only memory (ROM); random access memory (RAM); magnetic storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagation signals (e.g., carrier waves, infrared signals, digital signals, etc.). Furthermore, firmware, software, routines, and instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are merely for convenience, and such actions are actually generated by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc., and in doing so, enable actuators or other devices to interact with the physical world.

[0109] While specific embodiments of the invention have been described above, it should be understood that the invention can be practiced in ways other than those described. The above description is intended to illustrate and not limit. Therefore, it will be apparent to those skilled in the art that modifications can be made to the described invention without departing from the scope of the following claims.

Claims

1. A method of configuring a photolithography apparatus, the photolithography apparatus including an irradiator optics, the irradiator optics being configured to guide at least a portion of a radiation beam to an irradiation area of ​​a patterning apparatus to impart a pattern to the radiation beam and form a patterned radiation beam, the method comprising: The irradiator optics are configured such that at least two different portions of the patterning device receive radiation from different regions within a pupil plane associated with the irradiator optics, the at least two different portions being different at least in position along the scanning direction of the irradiation area; Radiation with a first angular distribution is received at a first portion of the irradiation area, and radiation with a second angular distribution is received at a second portion of the irradiation area, wherein the first and second portions are separated in the scanning direction, and the alignment of the spatial image associated with features on the patterning device depends on the coordinates of the radiation beam in the pupil plane; and Correcting spatial image displacement associated with the difference between the portion of the irradiated area.

2. The method of claim 1, further comprising receiving radiation such that the first angular distribution and the second angular distribution overlap at a third portion of the irradiated area.

3. The method of claim 2, wherein the angle distribution and area at the third portion are adjustable based on the adjustment of the first angle distribution and / or the second angle distribution.

4. The method of claim 3, wherein the spatial alignment displacement is caused by the mask 3D effect.

5. The method of claim 1, wherein the first angular distribution and the second angular distribution correspond to a monopole, wherein the full angular distribution is a y-dipole, and wherein the feature to be irradiated on the patterning device includes vertical lines.

6. The method according to claim 1, further comprising: The patterned radiation beam is projected onto the target area of ​​the substrate; Determine or predict image offset at the substrate level; as well as The angular distribution of radiation in the irradiated area is determined based on the determined or predicted image offset, wherein the angular distribution corresponds to the telecentric offset in the irradiated area.

7. The method of claim 6, wherein the predicted image offset is associated with a local tilt of the substrate.

8. The method of claim 3, wherein the spatial alignment displacement is caused by aberration changes along the scanning direction.

9. The method of claim 4, further comprising inducing aberration changes along the scanning direction based on the spatial image displacement and the configuration of the illuminator optics.

10. The method of claim 1, wherein the focal position of the spatial image associated with a feature on the patterning device depends on the coordinates of the radiation beam in the pupil plane, and the method further comprises homogenizing the spatial image based on the difference in focal position between the portions of the irradiated area.

11. The method of claim 1, wherein each of the different portions comprises a plurality of features, the plurality of features being positioned such that when the lithography apparatus is used in a dual-exposure setting to provide the different portions to the same area on the substrate, the corresponding positions of each of the plurality of features on the substrate are nominally equal between the different portions.

12. The method of claim 1, wherein the spatial alignment displacement is caused by a bias applied to the absorber portion of the patterning device.

13. The method of claim 12, wherein the applied bias is configured to optimize the amplitude of the diffraction order scattered from the patterning device to improve the contrast of the spatial image.

14. A computer program comprising program instructions operable, when run on a suitable device, to perform the method of claim 1.

15. A non-transitory computer program carrier, comprising the computer program according to claim 14.

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