WO2025201787A1

WO2025201787A1 - Masking blade

Info

Publication number: WO2025201787A1
Application number: PCT/EP2025/055286
Authority: WO
Inventors: Marcus Adrianus Van De Kerkhof; Krijn Frederik BUSTRAAN; Jim Vincent OVERKAMP; Adrianus Josephus Petrus VAN ENGELEN; Martinus Agnes Willem Cuijpers
Original assignee: ASML Netherlands BV
Current assignee: ASML Netherlands BV
Priority date: 2024-03-25
Filing date: 2025-02-27
Publication date: 2025-10-02
Anticipated expiration: 2026-09-25

Abstract

A masking module for a scanning lithographic apparatus. The masking module comprises at least two masking blades each configured to inhibit the transmission of at least a portion of electromagnetic radiation from a patterning device to a substrate during a scanning operation, wherein the at least two masking blades are in mechanical connection with one another. The masking module further comprises a driver configured to move the masking blades in a scanning direction during the scanning operation.

Description

MASKING BLADE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of EP application 24165903.6 which was filed on March 25, 2024 and EP application 24170739.7 which was filed on April 17, 2024 and which are incorporated herein in its entirety by reference.

FIELD

[0002] The present invention relates to a masking module which may be suitable for a lithographic apparatus. The lithographic apparatus may be an extreme ultraviolet (EUV) lithographic apparatus.

BACKGROUND

[0003] A lithographic apparatus is a machine constructed to apply a desired pattern onto a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern at a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) provided on a substrate.

[0004] To project a pattern on a substrate a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features which can be formed on the substrate. A lithographic apparatus, which uses extreme ultraviolet (EUV) radiation, having a wavelength within the range 4-20 nm, for example 6.7 nm or 13.5 nm, may be used to form smaller features on a substrate than a lithographic apparatus which uses, for example, radiation with a wavelength of 193 nm.

[0005] The volume around the patterning device of existing lithographic apparatus is very space constrained due to a large number of components and assemblies/modules existing close to the patterning device.

[0006] One such module is the masking module which typically acts to restrict the area of the patterning device illuminated by electromagnetic radiation by means of moveable masking blades, adjacent to the patterning device, configured to inhibit the transmission of electromagnetic radiation. [0007] Each existing masking blade is typically moved by a remote driver via long unsupported driver arm because space constraints in the volume around the patterning device preclude placement of the drivers nearer the masking blades. This makes the conventional masking blades and their support both very large and very heavy. Manufacturing conventional masking blades and there support is therefore challenging. Conventional masking blades and their support may also be too large and/or too heavy to be accommodated in future lithographic apparatus designs.

[0008] It may be desirable to provide an apparatus that obviates or mitigates one or more problems associated with the prior art. SUMMARY

[0009] According to a first aspect there is provided a masking module for a scanning lithographic apparatus, the masking module comprising: at least two masking blades each configured to inhibit the transmission of at least a portion of electromagnetic radiation from a patterning device to a substrate during a scanning operation, wherein the at least two masking blades are in mechanical connection with one another; and a driver configured to move the masking blades in a scanning direction during the scanning operation.

[00010] Due to space constraints immediately about the support structure (or reticle/mask table), conventional masking blades are typically actuated by remote actuators via long unsupported members. Conventionally masking blades are also driven individually, requiring a driver for each masking blade, making the conventional masking module very large and heavy. The mechanical connection between the masking blades advantageously enables a single driver to be used to drive the masking blades, resulting in a masking module comprising fewer driver components. Reducing the number of driver components may also make the masking module easier to manufacture.

[00011] The masking blades may be mounted to at least one shared support, such that the shared support mechanically connects the masking blades.

[00012] The use of a shared support may require few additional components and is relatively mechanically simple. The use of a shared support may therefore provide the benefits of mechanically connecting the masking blades without substantially increasing the mechanically complexity or cost of the masking blade module. The use of a shared support may increase the stiffness of the mechanical connection.

[00013] The masking blades may be mechanically connected to at least one actuator.

[00014] The actuator may be configured to adjust the spacing between the masking blades in the scanning direction during a non-scanning period.

[00015] Adjusting the spacing between the masking blades may advantageously enable a plurality of image area sizes on the patterning device to be accommodated.

[00016] The relative positions of the masking blades may be substantially fixed during the scanning operation.

[00017] The masking blades may be configured to define an opening between the masking blades. [00018] A first masking blade may be configured to inhibit the transmission of electromagnetic radiation to a first region of the patterning device during the scanning operation, and a second masking blade may be configured to inhibit the transmission of electromagnetic radiation to a third patterning device region during the scanning operation; wherein during at least a portion of the scanning operation the masking blades may be configured to allow the transmission of electromagnetic radiation to a second patterning device region via the opening between the masking blades.

[00019] The driver may be configured to move the masking blades during at least a portion of the scanning operation such that the velocities of the masking blades in the scanning direction are: less than or equal to the velocity of the patterning device in the scanning direction; and/or greater than or equal to the velocity of the patterning device in the scanning direction.

[00020] A first masking blade may be configured to inhibit the transmission of patterned electromagnetic radiation to a first region of the substrate during the scanning operation, and a second masking blade may be configured to inhibit the transmission of patterned electromagnetic radiation to a third substrate region during the scanning operation; wherein during at least a portion of the scanning operation the masking blades may be configured to allow the transmission of patterned electromagnetic radiation to a second substrate region via the opening between the masking blades.

[00021] The scanning operation may be a substantially continuous linear scan in the scanning direction; and wherein the patterning device may be configured to move with a non-zero velocity in the scanning direction during at least a portion of the scanning operation.

[00022] The use of a scanning operation may advantageously enable the use of a smaller beam size and/or cross-sectional area. The use of a scanning operation may advantageously enable the use of an EUV radiation source. The use of a scanning operation may advantageously provide more control over the region (e.g., the image area) of the patterning device that is illuminated. The use of a scanning operation may advantageously enable the use of a beam comprising electromagnetic radiation with a higher frequency and shorter wavelength.

[00023] The masking module may further comprise a controller configured to transmit control signals to the driver, wherein the control signals are configured to cause the driver to move the masking blades in the scanning direction during the scanning operation.

[00024] The driver may further comprise: at least one motor, at least one bearing, at least one drive arm; and wherein the driver may be configured to cause the motor to move the masking blades via the drive arm, and the drive arm is supported by the bearing.

[00025] According to a second aspect there is provided a scanning operation method for a scanning lithographic apparatus, the scanning operation method comprising: a first scanning phase, configured such that during the first scanning phase a first masking blade inhibits the transmission of electromagnetic radiation to a first region of a patterning device; a second scanning phase, configured such that during the second scanning phase electromagnetic radiation is transmitted to a second patterning device region via an opening between the first masking blade and a second masking blade; and a third scanning phase, configured such that during the third scanning phase the second masking blade inhibits the transmission of electromagnetic radiation to a third patterning device region; wherein the first masking blade and the second masking blade are in mechanical connection with one another.

[00026] A driver may be configured to move the masking blades in a scanning direction during the scanning operation.

[00027] The position of the first masking blade relative to the second masking blade may be substantially fixed during the scanning operation. [00028] The electromagnetic radiation may be a beam, and the width of the beam in the scanning direction may be less than the width of the opening in the scanning direction.

[00029] During the first scanning phase the beam may be directed towards the first patterning device region; during the second scanning phase the beam may be directed towards the second patterning device region; during the third scanning phase the beam may be directed towards the third patterning device region.

[00030] The first patterning device region and the second patterning device region may be separated by a first border; and the second patterning device region and the third patterning device region may be separated by a second border.

[00031] During the first scanning phase the first border may be substantially aligned with an internal edge of the first masking blade.

[00032] During the first scanning phase the velocities of the masking blades in the scanning direction may be substantially equal to the velocity of the patterning device in the scanning direction.

[00033] The velocities of the masking blades being substantially equal to the velocity of the patterning device may advantageously enable the first patterning device region to be masked by the first masking blade as the patterning device passes through the beam.

[00034] During the third scanning phase the second border may be substantially aligned with an internal edge of the second masking blade.

[00035] During the third scanning phase the velocities of the masking blades in the scanning direction are substantially equal to the velocity of the patterning device in the scanning direction.

[00036] The velocities of the masking blades being substantially equal to the velocity of the patterning device may advantageously enable the third patterning device region to be masked by the second masking blade as the patterning device passes through the beam.

[00037] During at least a portion of the second scanning phase the velocities of the masking blades in the scanning direction may be: less than or equal to the velocity of the patterning device in the scanning direction; and/or greater than or equal to the velocity of the patterning device in the scanning direction.

[00038] According to a third aspect there is provided a method of manufacturing a semiconductor device comprising the steps of: receiving a substrate with a photoresist layer and directing radiation using the scanning operation method as described to transfer a pattern from a mask onto the photoresist layer; and removing a portion of the photoresist layer to form the pattern over the substrate.

[00039] According to a fourth aspect there is provided a lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a support structure constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto the substrate; and a masking module as described. BRIEF DESCRIPTION OF THE DRAWINGS

[00040] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

Figure 1A depicts a lithographic system comprising a lithographic apparatus and a radiation source;

Figure IB depicts a side view of a scanning lithographic apparatus, which may be that shown in Figure 1A;

Figure 2 depicts a top-down view of an example masking module for a scanning lithographic apparatus;

Figure 3 depicts a side view of an example masking module, as shown in Figure 2;

Figure 4 depicts a side view of an example masking module, as shown in in Figures 2 and 3;

Figure 5 A depicts a side view of an example masking module in a first configuration, as shown in Figures 2 and 3;

Figure 5B depicts a side view of an example masking module in a second configuration, as shown in Figures 2 and 3;

Figure 6 depicts an example scanning operation method for a scanning lithographic apparatus;

Figure 7A-7C depict the relative positions of masking blades, patterning device, and electromagnetic radiation during various phases of the scanning operation method shown in Figure 6, viewed from below the masking blades and patterning device.

Figure 8 depicts the velocity in the scanning direction of the masking blades and the patterning device during the scanning operation method as shown in Figures 6-7C; and

Figure 9 depicts the velocity in the scanning direction of the masking blades and the patterning device during the scanning operation method as shown in Figures 6-7C.

DETAILED DESCRIPTION

[00041] Figure 1 A shows a lithographic system comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate electromagnetic radiation in the form of an EUV radiation beam B and to supply the EUV radiation beam B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT configured to support a patterning device MA (e.g., a mask), a projection system PS and a substrate table WT configured to support a substrate W.

[00042] The illumination system IL is configured to condition the EUV radiation beam B before the EUV radiation beam B is incident upon the patterning device MA. Thereto, the illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. The faceted field mirror device 10 and faceted pupil mirror device 11 together provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL may include other mirrors or devices in addition to, or instead of, the faceted field mirror device 10 and faceted pupil mirror device 11.

[00043] After being thus conditioned, the EUV radiation beam B interacts with the patterning device MA. The region of the patterning device MA illuminated by the radiation beam B may be at least partially defined by a masking module 12. As a result of this interaction, a patterned EUV radiation beam B’ is generated. The projection system PS is configured to project the patterned EUV radiation beam B’ onto the substrate W. For that purpose, the projection system PS may comprise a plurality of mirrors 13,14 which are configured to project the patterned EUV radiation beam B’ onto the substrate W held by the substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV radiation beam B’, thus forming an image with features that are smaller than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated as having only two mirrors 13,14 in Figure 1 A, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[00044] The substrate W may include previously formed patterns. Where this is the case, the lithographic apparatus LA aligns the image, formed by the patterned EUV radiation beam B’, with a pattern previously formed on the substrate W.

[00045] A relative vacuum, i.e. a small amount of gas (e.g. hydrogen) at a pressure well below atmospheric pressure, may be provided in the radiation source SO, in the illumination system IL, and/or in the projection system PS.

[00046] The lithographic apparatus LA and radiation source SO described herein can be used in method for performing a circuit layout patterning process. A circuit layout patterning method comprises receiving a substrate W with a photoresist layer. The method further comprises directing EUV radiation from radiation source SO to the photoresist layer to form a patterned photoresist layer. The method further comprises developing and etching the patterned photoresist layer to form a circuit layout.

[00047] The radiation source SO shown in Figure 1A is, for example, of a type which may be referred to as a laser produced plasma (LPP) source. A laser system 1, which may, for example, include a CO2 laser, is arranged to deposit energy via a laser beam 2 into a fuel (i.e., a target material), such as tin (Sn) which is provided from, e.g., a fuel generator 3. Although tin is referred to in the following description, any suitable fuel may be used. The fuel may, for example, be in liquid form, and may, for example, be a metal or alloy. The fuel generator 3 may comprise a nozzle configured to direct the fuel, e.g. in the form of droplets, along a trajectory towards a plasma formation region 4. The laser beam 2 is incident upon the fuel at the plasma formation region 4. The deposition of laser energy into the tin creates a plasma 7 at the plasma formation region 4. Radiation, including EUV radiation, is emitted from the plasma 7 during de-excitation and recombination of electrons with ions of the plasma 7.

[00048] The EUV radiation from the plasma 7 is collected and focused by a collector 5. Collector 5 comprises, for example, a near-normal incidence radiation collector 5 (sometimes referred to more generally as a normal-incidence radiation collector). The collector 5 may have a multilayer mirror structure which is arranged to reflect EUV radiation (e.g., EUV radiation having a desired wavelength such as 13.5 nm). The collector 5 may have an ellipsoidal configuration, having two focal points. A first one of the focal points may be at the plasma formation region 4, and a second one of the focal points may be at an intermediate focus 6, as discussed below.

[00049] The laser system 1 may be spatially separated from the radiation source SO. Where this is the case, the laser beam 2 may be passed from the laser system 1 to the radiation source SO with the aid of a beam delivery system (not shown) comprising, for example, suitable directing mirrors and/or a beam expander, and/or other optics. The laser system 1, the radiation source SO and the beam delivery system may together be considered to be a radiation system.

[00050] Electromagnetic radiation that is reflected by the collector 5 forms the EUV radiation beam B. The EUV radiation beam B is focused at intermediate focus 6 to form an image at the intermediate focus 6 of the plasma present at the plasma formation region 4. The image at the intermediate focus 6 acts as a virtual radiation source SO for the illumination system IL. The radiation source SO is arranged such that the intermediate focus 6 is located at or near to an opening 8 in an enclosing structure 9 of the radiation source SO.

[00051] The region of the patterning device MA illuminated by the EUV radiation beam B as partially or wholly defined by the masking module 12 may be referred to as the illumination region. The illumination region may be smaller than the patterning device MA in one or more directions.

[00052] In some examples the patterning device MA may be a reticle and/or any other suitable patterning device.

[00053] In an example lithographic apparatus LA, the lithographic apparatus LA may be a scanning lithographic apparatus LA. In a scanning lithographic apparatus LA the patterning device support structure MT may be movable in a scanning direction Y so as to expose a greater region of the patterning device MA in a single dynamic scanning exposure. The patterning device support structure MT is movably mounted. The lithographic apparatus LA may be considered to comprise a scanning module operable to move the patterning device support structure MT relative to a support frame. The EUV radiation beam B may have an extent which can only illuminate a portion of the patterning device MA in the scanning direction Y at any one time. The movement of the patterning device support structure MT allows a greater area of the patterning device MA to move through the path of the EUV radiation beam B, cumulatively exposing a greater region of the patterning device MA to electromagnetic radiation B in a single dynamic scanning exposure.

[00054] In some examples the substrate W may be a wafer and/or any other suitable substrate.

[00055] In some examples the EUV radiation beam B comprises, one or more of: electromagnetic radiation, EUV radiation. In some examples the electromagnetic radiation B is EUV radiation. In some examples the electromagnetic radiation is, one or more of: a beam, formed as a beam, a radiation beam, formed as a radiation beam, an EUV radiation beam, formed as an EUV radiation beam. [00056] Figure IB depicts a side view of a scanning lithographic apparatus LA, similar to that shown in Figure 1 A. In the example of Figure IB, the patterning device MA is a patterning device and the lithographic apparatus LA is a scanning lithographic apparatus LA. In Figure IB electromagnetic radiation B is directed from a radiation source SO towards the patterning device MA. The electromagnetic radiation B is depicted by the dashed arrows.

[00057] As shown in Figure IB, a masking blade 203 in the masking module 12 inhibits the transmission of at least a first portion of the electromagnetic radiation B to the patterning device MA. This is depicted in Figure IB by the dashed arrows terminating at the masking blade 203. In Figure IB at least a second portion of the electromagnetic radiation B is incident on the patterning device MA. In particular, some of the electromagnetic radiation B is incident on an image area 1001 of the patterning device MA. The electromagnetic radiation B incident on the image area 1001 illuminates the image area 1001. As shown in Figure IB, electromagnetic radiation B does not substantially illuminate areas outside of the image area 1001 (termed non-image areas 1003). The image area 1001 of the patterning device MA is an area of the patterning device MA comprising a pattern that a user selects to be illuminated during a scanning operation.

[00058] As discussed in relation to Figure 1A, the illuminated image area 1001 of the patterning device MA may generate patterned electromagnetic radiation B’. The patterned electromagnetic radiation B’ may be one or more of: a patterned beam; a patterned radiation beam; a patterned EUV radiation beam. The patterning device MA may generate the patterned electromagnetic radiation B’ by reflecting at least a portion of the incident electromagnetic radiation B. The patterning device MA may generate the patterned beam B’ by reflecting at least a portion of the incident beam B.

[00059] The patterned electromagnetic radiation B’ may expose a pattern on a field of the substrate W (substrate field 1005). As shown in Figure IB the patterned electromagnetic radiation B’ is not substantially incident on a neighbouring substrate field 1007, and does not substantially expose a pattern on a neighbouring substrate field 1007.

[00060] In this way the masking blade 203 defines the image area of the patterning device MA illuminated by the electromagnetic radiation B and thus defines a substrate field 1005 exposed to the patterned electromagnetic radiation B’ generated by the patterning device MA.

[00061] In the example of Figure IB the masking blade 203 is located between the illumination system IL and the patterning device MA, and thus inhibits the transmission of electromagnetic radiation B from the illumination system IL to the patterning device MA. Locating the masking blade 203 between the illumination system IL and the patterning device MA advantageously limits conflict of the masking blade 203 with components of the projection system PS downstream (in terms of photon flow) of the patterning device MA. However, whilst not shown in Figure IB, in other examples masking blades (i.e. the masking blade 203 or others) may be positioned between the patterning device MA and the projection system PS, inhibiting the transmission of patterned electromagnetic radiation B’ from the patterning device MA to regions of the substrate W and/or the projection system PS. [00062] In the example of Figure IB the masking blade 203 is configured to define the boundary of an image area 1001 on the patterning device MA running perpendicular to the scanning direction Y and parallel to the non-scanning direction X (i.e., normal to the plane of the page). Such a masking blade 203 may be termed a Y masking blade. Whilst not shown, a scanning lithographic apparatus LA may further comprise one or more X masking blades. An X masking blade may be configured to define the boundary of an image area 1001 on the patterning device MA running parallel to the scanning direction Y and perpendicular to the non-scanning direction X.

[00063] In the example of Figure IB, the electromagnetic radiation is a beam B and the width of the beam B in the scanning direction Y is less than the width (wr,M4) of the patterning device MA in the scanning direction Y (i.e., WY.MA)- The width may be less than the width (WY.IA) of an image area 1001 on the patterning device MA in the scanning direction Y vvr,«). Whilst not shown in Figure IB, the width of the beam B in the non-scanning direction X may be, one or more of: less than the width (WX.MA) of the patterning device MA in the non-scanning direction X (i.e., WX.MA), less than the width (WX.IA) of an image area 1001 on the patterning device MA in the non-scanning direction X (i.e., WX A)- The cross-sectional area of the beam B may be, less than the area of the patterning device MA and may be less than the area of the image area 1001. As discussed, to illuminate the full surface of the patterning device MA and/or the full image area 1001, the patterning device MA is moved relative the radiation beam B in the scanning direction Y. In this way a greater area of the patterning device MA may move through the path of the beam B, cumulatively exposing a greater region of the patterning device MA to electromagnetic radiation B in a single dynamic scanning exposure.

[00064] In a scanning operation (e.g., a dynamic scanning exposure of a field) the patterning device MA and Y masking blades move relative to the beam B in the Y direction, enabling an image area 1001 to be illuminated on the patterning device MA by the illumination region of the beam B. The Y masking blades delimit the edges of the image area 1001 orientated perpendicular to the scanning direction Y. Similarly, the X masking blades may delimit the edges of the image area 1001 perpendicular to the X direction. Multiple scanning operations may be used to illuminate different image areas 1001 on the patterning device MA. Multiple scanning operations may be used to expose different fields on the substrate W. Scanning operations are further described with respect to Figures 6-9.

[00065] A description of some additional features of an example type of lithographic apparatus LA is now provided with reference to Figures 2 to 10.

[00066] Figure 2 depicts an example masking module 12 for a scanning lithographic apparatus LA. [00067] The masking module 12 depicted in Figure 2 comprises at least two masking blades 203 A, 203B, each configured to inhibit the transmission of at least a portion of electromagnetic radiation from a patterning device MA to a substrate W during a scanning operation, wherein the at least two masking blades 203A, 203B are in mechanical connection with one another. The masking module 12 may be configured such that each masking blade 203A, 203B inhibits transmission of a portion of electromagnetic radiation to the substrate at a different time during the scanning operation. For example, the masking blade 203A may inhibit transmission of a portion of electromagnetic radiation to the substrate at a first time and the masking blade 203B may inhibit transmission of a portion of the electromagnetic radiation to the substarte at a second time that is later than the first time. The masking module 12 depicted in Figure 2 further comprises a driver 207 configured to move the masking blades 203A, 203B in a scanning direction Y during the scanning operation. In the example of Figure 2, the scanning direction may be the Y direction and the masking blades 203A, 203B may be Y masking blades.

[00068] In some examples the masking module 12 may comprise at least two masking blades 203 A, 203B configured to inhibit the transmission of electromagnetic radiation B to at least two regions of a patterning device MA during a scanning operation, wherein the at least two masking blades 203 A, 203B are in mechanical connection with one another.

[00069] In some examples the masking module 12 may comprise at least two masking blades 203 A, 203B configured to inhibit the transmission of patterned electromagnetic radiation B’ to at least two regions of a substrate W and/or the projection system PS during a scanning operation, wherein the at least two masking blades 203A, 203B are in mechanical connection with one another.

[00070] In the example of Figure 2 the masking blades 203 A, 203B are in mechanical connection with one another via mechanical connections 205. In some examples the masking blades 203 A, 203B may be mechanically connected by a single mechanical connection 205. In some examples the masking blades 203 A, 203B may be mechanically connected by a plurality of mechanical connections 205.

[00071] The mechanical connection between the masking blades 203A, 203B advantageously enables a driver 207 to be used to drive the masking blades 203A, 203B. In some examples, a single driver 207 may advantageously be used to drive the at least two masking blades 203A, 203B. The mechanical connection 205 between the masking blades 203A, 203B therefore results in a masking module 12 comprising fewer driver 207 components which may reduce, one or more of: the mass of the masking module 12, the size of the masking module 12. For example the masking module 12 may comprise fewer driver 207 components in the form of, one or more of: actuator components, sensor components, cooling components. Reducing the number of driver 207 components may also make the masking module 12 easier to manufacture.

[00072] It is desirable that the distance between the illumination system IL and the patterning device MA is small, to facilitate focussing the electromagnetic radiation B onto the patterning device MA. As shown in the example of Figure IB, the masking module 12 is positioned between the illumination system IL and the patterning device MA. As such, reducing the size of the masking module 12 may advantageously reduce the distance between the illumination system IL and the patterning device MA, enabling improved focussing of the electromagnetic radiation B onto the patterning device MA.

[00073] In some examples the relative positions of the masking blades 203A, 203B may be substantially fixed during the scanning operation. In some examples the masking blades 203A, 203B may be configured to define an opening between the masking blades 203 A, 203B. The spacing between the at least two masking blades 203A, 203B (and the width of the opening) in the scanning direction Y may be substantially fixed during the scanning operation. For example the spacing may be, one or more of: 90 mm, substantially 90 mm, approximately 90 mm, 88 to 92 mm, 85 to 95 mm, 80 to 100 mm, 75 to 105 mm, 70 to 110 mm. The spacing may be selected to reduce stroke and increase stiffness of the mechanical connection 205. The spacing may be selected to ensure the maximum acceleration of the masking blades 203A, 203B remains below an engineering tolerance. For example where the velocity of the patterning device MA in the scanning direction Y is 5.2 m/s and a beam B width is 22 mm, a spacing of 88 mm enables image area widths WY.IA of between 73 mm and 132 mm to be scanned without exceeding an engineering tolerance (approx. 400 m/s²) for the maximum acceleration of the masking blades 203A, 203B

[00074] The masking blades 203A, 203B may define the opening between the internal edges of the masking blades 203 A, 203B. The spacing may be measured between the internal edges of the masking blades 203 A, 203B.

[00075] In some examples the opening between the at least two masking blades 203 A, 203B may be a slit and/or a hole. In some examples the at least two masking blades 203A, 203B may be in mechanical connection with one another such that they form a single masking blade 203. In some examples the at least two masking blades 203 A, 203B may be integrated and/or integrally formed such that they form a single masking blade 203. The single masking blade 203 may comprise an opening, a slit and/or a hole as described.

[00076] In some examples the masking blades 203A, 203B may further comprise a plurality of slits and/or a plurality of holes, internal to the masking blade 203 (i.e., within the footprint of the masking blade 203). The plurality of slits and/or the plurality of holes internal to the masking blades 203 A, 203B may be used for special applications (e.g., Transmission Image Sensor exposures which may be used to measure the position at substrate level of a projected aerial image of a marker at the patterning device level).

[00077] In some examples a first masking blade 203A may be configured to inhibit the transmission of electromagnetic radiation B to a first region of the patterning device MA (also referred to as a first patterning device region) during the scanning operation. A second masking blade 203B may be configured to inhibit the transmission of electromagnetic radiation B to a third patterning device region during the scanning operation. During at least a portion of the scanning operation the masking blades 203A, 203B may be configured to allow the transmission of electromagnetic radiation B to a second patterning device region via the opening between the masking blades 203 A, 203B.

[00078] In some examples a first masking blade 203A may be configured to inhibit the transmission of a beam B to a first region of the patterning device MA (also referred to as a first patterning device region) during the scanning operation. A second masking blade 203B may be configured to inhibit the transmission of the beam B to a third patterning device region during the scanning operation. During at least a portion of the scanning operation the masking blades 203A, 203B may be configured to allow the transmission of the beam B to a second patterning device region via the opening between the masking blades 203 A, 203B.

[00079] The first patterning device region may be a patterning device region outside of the image area 1001. The first patterning device region may be a non-image area 1003 of the patterning device MA during the scanning operation. The second patterning device region may be a patterning device region within the image area 1001. The second patterning device region may be an image area 1001 and/or a portion of an image area 1001 of the patterning device MA during the scanning operation. The third patterning device region may be a patterning device region outside of the image area 1001. The third patterning device region may be a non-image area 1003 of the patterning device MA during the scanning operation.

[00080] The masking blades 203A, 203B may be configured to mask regions of the patterning device MA outside of the image area 1001 during the scanning operation. The masking blades 203A, 203B may be configured to allow the illumination by electromagnetic radiation B of an imaging area of the patterning device MA during the scanning operation. The opening defined by the masking blades 203A, 203B allows the transmission of electromagnetic radiation B and/or illumination by electromagnetic radiation B because the opening does not substantially inhibit the transmission of electromagnetic radiation B.

[00081] In some examples, during the portion of the scanning operation the second patterning device region may generate patterned electromagnetic radiation B’ and/or a patterned beam B’. The second patterning device region may generate the patterned electromagnetic radiation B’ and/or a patterned beam B’ by reflecting the electromagnetic radiation B and/or beam B incident on the second patterning device region. The patterned electromagnetic radiation B’ and/or a patterned beam B’ may be directed toward a substrate field 1005. The patterned electromagnetic radiation B’ and/or a patterned beam B’ may expose a substrate field 1005.

[00082] In some examples, the patterning device regions may not overlap. The first patterning device region may be positioned in front of (such that it is scanned before) a second patterning device region and the third patterning device region relative to the scanning direction Y. The second patterning device region may be positioned between the first patterning device region and the third patterning device region relative to the scanning direction Y. The third patterning device region may be positioned behind the first patterning device region and the second patterning device region relative to the scanning direction Y.

[00083] The first patterning device region (non-image area 1003) and the second patterning device region (image area 1001) may be separated in an axis perpendicular to the scanning direction Y (and parallel to the non-scanning direction X) by a first border. The first border may be a first black border of the image area 1001. The first border may be a first black border on the patterning device MA. The second patterning device region (image area 1001) and the third patterning device region (non-image area 1003) may be separated in an axis perpendicular to the scanning direction Y (and parallel to the non-scanning direction X) by a second border. The second border may be a second black border of the image area 1001. The second border may be a second black border on the patterning device MA. The first border and/or the second border may have a non-zero width in the scanning direction Y. The first border and/or the second border may have a width of, one or more of: 3.5 mm, substantially 3.5 mm, approximately 3.5 mm, between 3-4 mm.

[00084] After the scanning operation completes, the patterning device MA is moved to a new start position in the scanning direction Y and the non-scanning direction X to enable further scanning operations. After the scanning operation completes, the masking module 12 may be moved to a new start position in the scanning direction Y to enable further scanning operations. The further scanning operations may be used to illuminate other image areas 1001 on the patterning device MA. The other image areas 1001 may or may not overlap with the original image area 1001. The further scanning operations may be used to expose different substrate W fields 1005, 1007.

[00085] Whilst not shown in Figure IB and Figure 2, in some examples a first masking blade 203A may be configured to inhibit the transmission of patterned electromagnetic radiation B’ to a first region of the substrate W (also referred to as a first substrate region) during the scanning operation. A second masking blade 203B may be configured to inhibit the transmission of patterned electromagnetic radiation B’ to a third substrate region during the scanning operation. During at least a portion of the scanning operation the masking blades 203A, 203B may be configured to allow the transmission of patterned electromagnetic radiation B’ to a second substrate region via the opening between the masking blades 203 A, 203B.

[00086] In some examples a first masking blade 203A may be configured to inhibit the transmission of a patterned beam B’ to a first region of the substrate (also referred to as a first substrate region) during the scanning operation. A second masking blade 203B may be configured to inhibit the transmission of the patterned beam B’ to a third substrate region during the scanning operation. During at least a portion of the scanning operation the masking blades 203 A, 203B may be configured to allow the transmission of the patterned beam B’ to a second substrate region via the opening between the masking blades 203 A, 203B.

[00087] The first substrate region may be a substrate region outside of an exposure substrate field 1005. The first substrate region may be an adjacent substrate field 1007. The second substrate region may be a substrate region within the exposure substrate field 1005. The third substrate region may be a substrate region outside of the exposure field 1005. The third substrate region may be another adjacent substrate field.

[00088] The masking blades 203A, 203B may be configured to mask regions of the substrate W outside of the exposure substrate field 1007 during the scanning operation. The masking blades 203 A, 203B may be configured to allow the illumination by patterned electromagnetic radiation B’ of an exposure field of the substrate W during the scanning operation. The opening defined by the masking blades 203 A, 203B allows the transmission of patterned electromagnetic radiation B’ and/or exposure by patterned electromagnetic radiation B’ because the opening does not substantially inhibit the transmission of patterned electromagnetic radiation B’.

[00089] Whilst not shown in Figure 2, the masking module 12 may further comprise at least two supplementary masking blades configured to inhibit the transmission of electromagnetic radiation B to supplementary regions of the patterning device MA during the scanning operation. The supplementary regions may be non-image areas 1003 of the patterning device MA. The supplementary masking blades may be orientated perpendicular to the non-scanning direction X and parallel to the scanning direction Y. The supplementary masking blades may be X masking blades. The supplementary regions may be substantially perpendicular to the regions. The supplementary masking blades may not be moved by the driver 207 during the scanning operation. The positions of the supplementary masking blades may be substantially fixed relative to the lithographic apparatus LA and/or the masking module 12 during the scanning operation. The spacing (wx,o_Pen) in the non-scanning direction X between the supplementary masking blades may be substantially fixed during scanning operation. The supplementary masking blades may be moved in the non-scanning direction X by one or more supplementary drivers (not shown) during a non-scanning period. The non-scanning period may be, one or more of: a period before a scanning operation, a period between scanning operations, a period after a scanning operation. The non-scanning period may be a period between lots. The spacing wx,o_pen may be adjusted once per lot. The spacing wx,o_pen may be one or more of: 26 mm, substantially 26 mm, approximately 26 mm, between 25 to 27 mm, between 20-30 mm.

[00090] Whilst not shown in Figure 2, the distance (IIZ,SMB-MA) between the supplementary masking blades and the patterning device MA in a direction Z perpendicular to both the scanning direction Y and the non-scanning direction X may be less than the distance (IIZ,MB-MA) between the masking blades 203 and the patterning device MA in the Z direction (i.e., !IZ,SMB-MA < IIZMB-MA)- The distance !VZ,SMB-MA may be one or more of: 5 mm, substantially 5 mm, approximately 5 mm. The distance IIZ,MB-MA may be one or more of: 10 mm, substantially 10 mm, approximately 10 mm.

[00091] In some examples the supplementary masking blades are substantially fixed both during the scanning operation and outside of the scanning operation. In these examples different image area 1001 widths in the non-scanning direction X may be accommodated by changing the width of the image area border (i.e. the border between the image area 1001 and non-image area 1003 on the patterning device MA) in the non-scanning direction X. The image area border may be a black border.

[00092] In some examples the masking module 12 does not comprise the supplementary masking blades. In these examples the image area 1001 width in the non-scanning direction X may be determined by the width of the image area border and the width of the beam B.

[00093] In some examples, the driver 207 may be configured to move the masking blades 203A, 203B during at least a portion of the scanning operation such that the velocities of the masking blades 203A, 203B in the scanning direction Y are: less than or equal to the velocity of the patterning device MA in the scanning direction Y and/or greater than or equal to the velocity of the patterning device MA in the scanning direction Y.

[00094] The velocities of the masking blades 203A, 203B in the scanning direction Y may be less than or equal to the velocity of the patterning device MA in the scanning direction Y when the width of the image area WY.IA is greater than or equal to the spacing WY,o_Pen- The velocities of the masking blades 203A, 203B in the scanning direction Y may be less than or equal to the velocity of the patterning device MA in the scanning direction Y when the width of the image area WY.IA is greater than or equal to approximately two-thirds of the spacing WY, open-

100095] The velocities of the masking blades 203 A, 203B may change during a scanning operation. [00096] The width of the image area WY.IA being substantially equal to approximately two-thirds of the spacing wy.open may advantageously enable the exposure on the substrate W of fields with a width in the scanning direction Y of, one or more of: 11 mm, substantially 11 mm, approximately 11 mm, between 10.5 and 11.5 mm, between 10 and 12 mm, between 9 and 13 mm.

[00097] The velocities of the masking blades 203 A, 203B in the scanning direction Y may be greater than or equal to the velocity of the patterning device MA in the scanning direction Y when the width of the image area WY.IA is less than approximately two-thirds of the spacing WY, open-

100098] The masking blades 203 A, 203B may advantageously enable an image area 1001 on a patterning device MA to be more sharply delimited, resulting in the field 1005 exposed on a substrate W being more sharply delimited. The masking blades 203A, 203B may advantageously reduce the transmission of stray patterned electromagnetic radiation B’ to neighbouring substrate fields 1007 and so allow for greater packing of fields on the substrate W.

[00099] In the example of Figure 2, the scanning operation may be a substantially continuous linear scan in the scanning direction Y. The patterning device MA may be configured to move with a nonzero velocity in the scanning direction Y during at least a portion of the scanning operation. The patterning device MA may be configured to move with a non-zero velocity in the scanning direction Y relative to the beam B and/or the electromagnetic radiation B during at least a portion of the scanning operation. The patterning device MA may be configured to move with a non-zero velocity in the scanning direction Y during at least a portion of the scanning operation, wherein the non-zero velocity is one or more of: 5.2 m/s, substantially 5.2 m/s, approx. 5.2 m/s, between 5.0-5.5 m/s, between 4.5-6.0 m/s, between 4.0-7.0 m/s.

[000100] The scanning operation may not be a flood-illumination operation. The scanning operation may not be a step-and-repeat operation.

[000101] The use of a scanning operation may advantageously enable the use of a smaller a beam B size and/or cross-sectional area. The use of a scanning operation may advantageously enable the use of an EUV radiation source SO. The use of a scanning operation may advantageously provide more control over the region (e.g., the image area 1001) of the patterning device MA that is illuminated. The use of a scanning operation may advantageously enable the use of a beam B comprising electromagnetic radiation with a higher frequency and shorter wavelength.

[000102] Whilst not shown in Figure 2, in some examples the masking module 12 may comprise a controller configured to transmit control signals to the driver 207. The control signals may be configured to cause the driver 207 to move the masking blades 203 A, 203B in the scanning direction Y during the scanning operation. The controller may be a computing device. The controller may comprise, one or more of: a memory, a storage, a processor.

[000103] In some examples the controller may be configured to send control signals to one or more supplementary drivers (not shown).

[000104] Figure 3 depicts a side view of an example masking module 12, as shown in Figure 2.

[000105] The driver 207 in the example of Figure 3 further comprises: at least one motor 301, at least one bearing 303, at least one drive arm 305. The driver 207 is configured to cause the motor 301 to move the masking blades 203 via the drive arm 305, and the drive arm 305 is supported by the bearing 303.

[000106] The motor 301 may comprise one or more of: a linear motor motion system (LIMMS), a Lorentz motor. Advantageously, the LIMMS may be stronger and/or more efficient compared to the Lorentz motor. A LIMMS may be used preferentially in the masking module 12 shown in Figures 2 and 3.

[000107] The bearing 303 may be an air bearing. As shown in the example of Figure 3, the motor 301 and the bearing 303 may be integrated and/or integrally formed. Where the motor 301 and the bearing 303 are integrated and/or integrally formed, the motor 301 may perform an electromagnetic bearing function.

[000108] The skilled person would appreciate that in other examples the motor 301 and the bearing 303 may be separate and/or physically separated components.

[000109] In the example masking module 12 shown in Figure 3, the motor 301 is connected to the masking blades 203 and/or the mechanical connection(s) 205 via a drive arm(s) 305. The skilled person would appreciate that whilst only one mechanical connection 205 and one drive arm 305 are shown in Figure 3, the masking module 12 may comprise a plurality of mechanical connections 205 and/or a plurality of drive arms 305.

[000110] In some examples the motor 301 may be positioned between two bearings 303 and/or two drive arms 305. The two bearings 303 and/or two drive arms 305 may be arranged substantially parallel to one another and substantially parallel to the scanning direction Y, such that a space is defined between the two bearings 303 and/or two drive arms 305. The motor 301 may be positioned in this space. Advantageously, this driver 207 configuration may occupy a smaller volume compared to a conventional driver configuration in which each bearing 303 and/or drive arm is associated with a separate motor. [000111] Figure 4 depicts a side view of an example masking module 12, as shown in in Figures 2 and 3.

[000112] In the example of Figure 4, the masking blades 203 are mounted to at least one shared support 401, such that the shared support 401 mechanically connects the masking blades 203. In the example of Figure 4, the mechanical connection 205 comprises the shared support 401. In some examples the masking blades 203 may be mechanically connected by a single shared support 401. In some examples the masking blades 203 may be mechanically connected by a plurality of shared supports 401.

[000113] In some examples the masking blades 203 may be mounted to the shared support 401, and the shared support 401 may be mounted to the drive arm 305. For example, a first shared support 401 may be mounted to a first drive arm 305 and a second shared support 401 may be mounted to a second drive arm 305. In this example the masking blades 203 may be mounted to the first shared support 401 and the second shared support 401. The shared support 401 may be a bracket and/or any other suitable supporting means.

[000114] The use of a shared support 401 to mechanically connect the masking blades 203 advantageously requires few additional components and is relatively mechanically simple. The use of a shared support 401 therefore provides benefits of mechanically connecting the masking blades 203 (as previously discussed) without substantially increasing the mechanically complexity or cost of the masking blade module 12. The use of a shared support 401 may increase the stiffness of the mechanical connection 205.

[000115] Figure 5A depicts a side view of an example masking module 12, as shown in Figures 2 and 3.

[000116] In the example of Figure 5A the masking blades 203 are mechanically connected to at least one actuator 501. In the example of Figure 5A the at least one actuator 501 is in a first configuration. The first configuration may be an extended configuration and/or a substantially extended configuration. [000117] In some examples the masking blades 203 may be in mechanical connection with one another via at least one actuator 501.

[000118] In some examples the actuator 501 may be mounted to a drive arm 305. A first masking blade 203A may be mounted the actuator 501 by a first support 503A, and a second masking blade 203B may be mounted to the drive arm 305 by a second support 503B. The masking blades 203 A, 203B may both be mounted to and driven by at least one shared drive arm 305.

[000119] Whilst not shown in Figure 5A, the skilled person would appreciate that a first actuator 501 may be mounted to a first drive arm 305 and a second actuator 501 may be mounted to a second drive arm 305.

[000120] In some examples the actuator 501 may further comprise a brake 505. The brake 505 may be positioned between the first support 503A and the second support 503B. The brake 505 may be used during scanning operation to inhibit movement of the first support 503A relative to the second support 503B, thus inhibiting the movement of the first masking blade 203A relative to the second masking blade 203B. The brake 505 may advantageously be used to increase the stiffness of the mechanical connection 205 between the first masking blade 203 A and the second masking blade 203B.

[000121] In some examples the actuator 501 may be, one or more of: a mechanical guide, a flexure guide, a push-pull rod. In some examples the push-pull rod may be housed in a substantially closed environment and/or sleeve. The substantially closed environment and/or sleeve may be configured to inhibit the release of particles into the lithographic apparatus LA. The actuator 501 may be configured to have good defectivity performance. The actuator 501 may be particle free and/or substantially particle free.

[000122] Particle free and/or substantially particle free actuators 501 may advantageously maintain good defectivity performance in proximity to the patterning device MA, by reducing contamination of the patterning device MA. Particle free and/or substantially particle free actuators 501 may advantageously improve the performance of the lithographic apparatus LA by reducing contamination of the patterning device MA.

[000123] In some examples the actuator 501 is configured to adjust the spacing between the masking blades 203 in the scanning direction Y during a non-scanning period.

[000124] The actuator 501 may be configured to adjust the spacing between the masking blades 203 in the scanning direction Y. As previously discussed, the non-scanning period may be, one or more of: a period before a scanning operation, a period between scanning operations, a period after a scanning operation. The non-scanning period may be a period in which a scanning operation is not taking place. The non-scanning period may be a period between lots. The spacing may be adjusted once per lot. Adjusting the spacing may be relatively slow compared to the scanning operation.

[000125] Adjusting the spacing between the masking blades 203 may advantageously enable a plurality of image area 1001 sizes on the patterning device MA to be accommodated. In particular, adjusting the spacing in the scanning direction Y may enable a plurality of image area 1001 widths in the scanning direction Y to be accommodated. The masking module 12 may therefore provide the benefits of mechanically connecting the masking blades 203 whilst increasing the tolerance with regard to image sizes on the patterning device MA.

[000126] In some examples the actuator 501 may have a low mass. In some examples the actuator 501 may have a relatively low mass compared to one or more of: the driver 207, the drive arm 305.

[000127] Figure 5B a side view of an example masking module 12, as shown in Figures 2 and 3. In the example of Figure 5A the at least one actuator 501 is in a second configuration. In this second configuration the actuator 501 has a smaller length in the scanning direction Y relative to the first configuration as depicted in Figure 5A. In this second configuration the spacing between the masking blades 203 in the scanning direction Y is reduced relative to the first configuration as depicted in Figure 5A. The second configuration may be a retracted configuration and/or a substantially retracted configuration. The skilled person would appreciate that the actuator 501 may also increase the spacing Y,open-

[000128] In some examples the difference between wy.open in the first actuator configuration and wr.open in the second actuator configuration may be one or more of: 30 mm, substantially 30 mm, approximately 30 mm, on the order of 30 mm.

[000129] Figure 6 depicts an example scanning operation method for a scanning lithographic apparatus LA that may be performed by the masking module 12 shown in Figures 1A to 5B.

[000130] The example scanning operation method for a scanning lithographic apparatus LA shown in Figure 6 comprises block 601, block 603 and block 605.

[000131] In the example of Figure 6, block 601 is a first scanning phase. The first scanning phase 601 is configured such that during the first scanning phase 601 a first masking blade 203A inhibits the transmission of electromagnetic radiation B to the first region of a patterning device MA.

[000132] In the example of Figure 6, block 603 is a second scanning phase. The second scanning phase 603 is configured such that during the second scanning phase 603 electromagnetic radiation B is transmitted to a second patterning device region via an opening between the first masking blade 203 A and a second masking blade 203B.

[000133] In the example of Figure 6, block 605 is a third scanning phase. The third scanning phase 605 is configured such that during the third scanning phase 605 the second masking blade 203B inhibits the transmission of electromagnetic radiation B to a third patterning device region.

[000134] In the scanning operation method depicted in Figure 6, the first masking blade 203A and the second masking blade 203B are in mechanical connection with one another.

[000135] The skilled person would appreciate that in other examples of the scanning operation method, in block 601 and block 605 the masking blades 203 may inhibit the transmission of patterned electromagnetic radiation B’ to regions of a substrate W and/or the projection system PS. Similarly, the skilled person would appreciate that in other examples of the scanning operation, in block 603 patterned electromagnetic radiation B’ may be transmitted to regions of a substrate W and/or the projection system PS via an opening between the masking blades 203.

[000136] Similarly termed features (e.g., masking blades 203) shown in Figure 6 may correspond to those features as described in relation to the previous examples shown in Figures 1-5B.

[000137] In some examples block 601 precedes block 603, and block 603 precedes block 605. Similarly, in some examples block 603 follows block 601, and block 605 follows block 603. The skilled person would appreciate that the blocks 601, 603, 605 may be performed in any other suitable order.

[000138] In some examples the first scanning phase 601 precedes the second scanning phase 603, and the second scanning phase 603 precedes the third scanning phase 605. Similarly, in some examples the second scanning phase 603 follows the first scanning phase 601, and the third scanning phase 605 follows the second scanning phase 603. The skilled person would appreciate that the scanning phases may be performed in any other suitable order. [000139] In some examples, a driver 207 is configured to move the masking blades 203 in a scanning direction Y during the scanning operation shown in Figure 6. The driver may correspond to the driver 207 discussed in relation to the previous examples shown in Figures 1-5B.

[000140] In some examples the position of the first masking blade 203A relative to the second masking blade 203B is substantially fixed during the scanning operation.

[000141] Figure 7A-7C depict the relative positions of masking blades 203, patterning device MA, and electromagnetic radiation during various phases of the scanning operation method shown in Figure 6, viewed from below the masking blades 203 and patterning device MA.

[000142] In the example of Figure 7, the electromagnetic radiation B, 703 is a beam B. The width of the beam B, 703 in the scanning direction Y is less than the width of the opening in the scanning direction Y.

[000143] In some examples the width of the beam B, 703 in the scanning direction Y may be one or more of: less than the width WY.MA of the patterning device MA in the scanning direction Y; substantially less that the width WY,MA of the patterning device MA in the scanning direction Y. The width of the beam B, 703 in the scanning direction Y may be one or more of: less than the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y; substantially less that the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y. The width of the beam B, 703 in the scanning direction Y may be, one or more of: 22 mm, substantially 22 mm, approximately 22 mm, between 21-23 mm, between 20-25 mm, between 15-30 mm.

[000144] The width of the beam B, 703 in the non-scanning direction X may be, one or more of: equal to the width WX.MA of the patterning device MA in the non-scanning direction X; substantially equal to the width WX.MA of the patterning device MA in the non-scanning direction X. The width of the beam B, 703 in the non-scanning direction X may be, one or more of: equal to the width WX.IA of the image area 701, 1001 on the patterning device MA in the non-scanning direction X; substantially equal to the width of the image area WX.IA on the patterning device MA in the non-scanning direction X. [000145] The width of the beam B, 703 in the non-scanning direction X may be greater than the width of the beam B, 703 in the scanning direction Y. The beam B, 703 may be elongate in the non-scanning direction X. The beam B, 703 may be a beam slit.

[000146] The use of a beam B, 703 to illuminate the patterning device MA may provide more control over the region of the patterning device MA that is illuminated. The use of a beam B, 703 may enable the use of electromagnetic radiation with a higher frequency and shorter wavelength (e.g., EUV radiation).

[000147] Figure 7A depicts a portion of the first scanning phase 601 at time During the first scanning phase 601 the beam B, 703 is directed towards the first patterning device region. In the example Figure 7A, the first patterning device region is the non-image area 1003 above masking blade 203A and outside of the image area 701, 1001. As shown in Figure 7A the masking blade 203A inhibits the transmission of electromagnetic radiation in the form of beam B, 703 to the non-image area 1003 above the masking blade 203 A and outside of the image area 701, 1001.

[000148] Figure 7B depicts a portion of the second scanning phase 603 at time . At time t₂, the patterning device MA (including the image area 701, 1001) and the masking blades 203 have moved in the scanning direction Y relative to the beam B, 703. During the second scanning phase 603 the beam B, 703 is directed towards the second patterning device region. In the example of Figure 7B, the second patterning device region is the image area 701, 1001 above the opening between the first masking blade 203A and the second masking blade 203B. As shown in Figure 7B, electromagnetic radiation in the form of beam B, 703 is transmitted to the image area 701, 1001 above the opening between the first masking blade 203 A and the second masking blade 203B.

[000149] Figure 7C depicts a portion of the third scanning phase 605 at time tj. At time fc, the patterning device MA (including the image area 701, 1001) and the masking blades 203 have again moved in the scanning direction Y relative to the beam B, 703. During the third scanning phase 605 the beam B, 703 is directed towards the third patterning device region. During the third scanning phase 605 the beam B, 703 is directed towards the third patterning device region. In the example Figure 7A, the third patterning device region is the non-image area 1003 above masking blade 203B and outside of the image area 701, 1001. As shown in Figure 7C the masking blade 203B inhibits the transmission of electromagnetic radiation in the form of beam B, 703 to the non-image area 1003 above the masking blade 203B and outside of the image area 701.

[000150] In some examples the first patterning device region and the second patterning device region may be separated by a first border 701 A. The first border 701 A may be a first black border of the image area 701, 1001. The first border may be a first black border on the patterning device MA.

[000151] In some examples the second patterning device region and the third patterning device region may be separated by a second border 701B. The second border 701B may be a second black border of the image area 701, 1001. The second border 701B may be a second black border on the patterning device MA.

[000152] As previously discussed, the first border 701 A and/or the second border 701B may have a non-zero width in the scanning direction Y. The first border 701A and/or the second border 701B may have a width of, one or more of: 3.5 mm, substantially 3.5 mm, approximately 3.5 mm, between 3-4 mm.

[000153] As shown in the example of Figure 7 A, during the first scanning phase 601 the first border 701 A may be substantially aligned with an internal edge of the first masking blade 203 A. In some examples the centre of the first border 701A may be substantially aligned with an internal edge of the first masking blade 203A.

[000154] As shown in the example of Figure 7C, during the third scanning phase 605 the second border 70 IB may be substantially aligned with an internal edge of the second masking blade 203B. In some examples the centre of the second border 701B may be substantially aligned with an internal edge of the second masking blade 203B.

[000155] Whilst Figures 7A-7C depict the width wy.open of the opening between the masking blades 203 in the scanning direction Y as less than the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y, the skilled person would appreciate that the width WY.open of the opening may be one or more of: greater than the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y ; equal to or substantially equal to the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y; less that the width WY.IA of the image area 701, 1001 on the patterning device MA in the scanning direction Y.

[000156] In some examples the second scanning phase 603 may commence when, one or more of: the internal edge of the first masking blade 203A exits a beam B, 703 directed at the patterning device MA; the first border 701A exits a beam B, 703 directed at the patterning device MA; the centre of the first border 701A exits a beam B, 703 directed at the patterning device MA.

[000157] In some examples the third scanning phase 605 may commence when, one or more of: the internal edge of the second masking blade 203B enters a beam B, 703 directed at the patterning device MA; the second border 701B enters a beam B, 703 directed at the patterning device MA; the centre of the second border 701B enters a beam B, 703 directed at the patterning device MA.

[000158] In some examples ti < t < fc.

[000159] Figure 8 depicts the velocity 805 in the scanning direction Y of the masking blades 203 and the velocity 807 in the scanning direction Y of the patterning device MA during the scanning operation method as shown in Figures 6-7C. Similarly, Figure 9 depicts the velocity 905 in the scanning direction Y of the masking blades 203 and the velocity 907 in the scanning direction Y of the patterning device MA during a scanning operation method as shown in Figures 6-7C.

[000160] In Figure 8 the x axis 801 is time t, and the y axis 803 is velocity VY in the scanning direction Y. Similarly, in Figure 9 the x axis 901 is time t, and the y axis 903 is velocity VY in the scanning direction Y.

[000161] As shown in the examples of Figures 8 and 9, during the first scanning phase 601 the velocities 805 of the masking blades 203 in the scanning direction Y are substantially equal to the velocity 807 of the patterning device MA in the scanning direction Y.

[000162] The velocities 805 of the masking blades 203 being substantially equal to the velocity 807 of the patterning device MA advantageously enables the first patterning device region to be masked by the first masking blade 203A as the patterning device MA passes through the beam B, 703.

[000163] As shown in the examples of Figures 8 and 9, during the third scanning phase 605 the velocities 805 of the masking blades 203 in the scanning direction Y are substantially equal to the velocity 807 of the patterning device MA in the scanning direction Y. [000164] The velocities 805 of the masking blades 203 being substantially equal to the velocity of the patterning device MA advantageously enables the third patterning device region to be masked by the second masking blade 203B as the patterning device MA passes through the beam B, 703.

[000165] As shown in the example of Figure 8, during at least a portion of the second scanning phase 603 the velocities 805 of the masking blades 203 in the scanning direction Y are less than or equal to the velocity 807 of the patterning device MA in the scanning direction Y.

[000166] In some examples the masking blades 203 may decelerate in the scanning direction Y between the first scanning phase 601 and the second scanning phase 603. The masking blades 203 may accelerate in the scanning direction Y between the second scanning phase 603 and the third scanning phase 605.

[000167] As previously described, velocities 805 of the masking blades 203 in the scanning direction

Y which are less than or equal to the velocity 807 of the patterning device MA in the scanning direction

Y during the second scanning phase 603 advantageously enable illumination of an image area 701, 1001 during a scanning operation in which the width WY.IA of the image area 701, 1001 in the scanning direction Y is one or more of: greater than the spacing wr.open between the masking blades 203 in the scanning direction Y, greater than or equal to approximately two-thirds of the spacing WY,_open between the masking blades 203 in the scanning direction Y.

[000168] As shown in the example of Figure 9, during at least a portion of the second scanning phase 603 the velocities 805 of the masking blades 203 in the scanning direction Y are greater than or equal to the velocity 807 of the patterning device MA in the scanning direction Y.

[000169] In some examples the masking blades 203 may accelerate in the scanning direction Y between the first scanning phase 601 and the second scanning phase 603. The masking blades 203 may decelerate in the scanning direction Y between the second scanning phase 603 and the third scanning phase 605.

[000170] As previously described, velocities 805 of the masking blades 203 in the scanning direction

Y which are greater than or equal to the velocity 807 of the patterning device MA in the scanning direction Y during the second scanning phase 603 advantageously enable illumination of an image area 701, 1001 during a scanning operation in which the width WY.IA of the image area 701, 1001 in the scanning direction Y is less than approximately two-thirds the spacing WY,_open between the masking blades 203 in the scanning direction Y.

[000171] References 809 and 909 illustrate the maximum velocity of the patterning device MA in the scanning direction Y during the scanning operation.

[000172] Although specific reference may be made in this text to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquidcrystal displays (LCDs), thin-film magnetic heads, etc. [000173] Although specific reference may be made in this text to embodiments of the invention in the context of a lithographic apparatus, embodiments of the invention may be used in other apparatus. Embodiments of the invention may form part of a mask inspection apparatus, a metrology apparatus, or any apparatus that measures or processes an object such as a wafer (or other substrates) or mask (or other patterning devices). These apparatus may be generally referred to as lithographic tools. Such a lithographic tool may use vacuum conditions or ambient (non- vacuum) conditions.

[000174] Although specific reference may have been made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention, where the context allows, is not limited to optical lithography and may be used in other applications, for example imprint lithography.

[000175] Where the context allows, embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the 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 form readable by a machine (e.g., a computing device). 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, acoustical, and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions in fact result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc. and in doing that may cause actuators or other devices to interact with the physical world.

[000176] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. The descriptions above are intended to be illustrative, not limiting. Thus it will be apparent to one skilled in the art that modifications may be made to the invention as described without departing from the scope of the claims set out below.

Claims

1. A masking module for a scanning lithographic apparatus, the masking module comprising: at least two masking blades each configured to inhibit the transmission of at least a portion of electromagnetic radiation from a patterning device to a substrate during a scanning operation, wherein the at least two masking blades are in mechanical connection with one another; and a driver configured to move the masking blades in a scanning direction during the scanning operation.

2. The masking module as claimed in claim 1, wherein the masking blades are mounted to at least one shared support, such that the shared support mechanically connects the masking blades.

3. The masking module as claimed in claim 1, wherein the masking blades are mechanically connected to at least one actuator.

4. The masking module as claimed in claim 3, wherein the actuator is configured to adjust the spacing between the masking blades in the scanning direction during a non-scanning period.

5. The masking module as claimed in any preceding claim, wherein the relative positions of the masking blades are substantially fixed during the scanning operation.

6. The masking module as claimed in any proceeding claim, wherein the masking blades are configured to define an opening between the masking blades.

7. The masking module as claimed in claim 6, wherein a first masking blade is configured to inhibit the transmission of electromagnetic radiation to a first region of the patterning device during the scanning operation, and a second masking blade is configured to inhibit the transmission of electromagnetic radiation to a third patterning device region during the scanning operation; wherein during at least a portion of the scanning operation the masking blades are configured to allow the transmission of electromagnetic radiation to a second patterning device region via the opening between the masking blades.

8. The masking module as claimed in claim 7, wherein the driver is configured to move the masking blades during at least a portion of the scanning operation such that the velocities of the masking blades in the scanning direction are: less than or equal to the velocity of the patterning device in the scanning direction; and/or greater than or equal to the velocity of the patterning device in the scanning direction.

9. The masking module as claimed in claim 6, wherein a first masking blade is configured to inhibit the transmission of patterned electromagnetic radiation to a first region of the substrate during the scanning operation, and a second masking blade is configured to inhibit the transmission of patterned electromagnetic radiation to a third substrate region during the scanning operation; wherein during at least a portion of the scanning operation the masking blades are configured to allow the transmission of patterned electromagnetic radiation to a second substrate region via the opening between the masking blades.

10. The masking module as claimed in any preceding claim, wherein the scanning operation is a substantially continuous linear scan in the scanning direction; and wherein the patterning device is configured to move with a non-zero velocity in the scanning direction during at least a portion of the scanning operation.

11. The masking module as claimed in any preceding claim, further comprising a controller configured to transmit control signals to the driver, wherein the control signals are configured to cause the driver to move the masking blades in the scanning direction during the scanning operation.

12. The masking module as claimed in any preceding claim, wherein the driver further comprises: at least one motor, at least one bearing, at least one drive arm; and wherein the driver is configured to cause the motor to move the masking blades via the drive arm, and the drive arm is supported by the bearing.

13. A scanning operation method for a scanning lithographic apparatus, the scanning operation method comprising: a first scanning phase, configured such that during the first scanning phase a first masking blade inhibits the transmission of electromagnetic radiation to a first region of a patterning device; a second scanning phase, configured such that during the second scanning phase electromagnetic radiation is transmitted to a second patterning device region via an opening between the first masking blade and a second masking blade; and a third scanning phase, configured such that during the third scanning phase the second masking blade inhibits the transmission of electromagnetic radiation to a third patterning device region; wherein the first masking blade and the second masking blade are in mechanical connection with one another.

14. The scanning operation method as claimed in claim 13, wherein a driver is configured to move the masking blades in a scanning direction during the scanning operation.

15. The scanning operation method as claimed in claim 13 or 14, wherein the position of the first masking blade relative to the second masking blade is substantially fixed during the scanning operation.

16. The scanning operation method as claimed in claims 13 to 15, wherein the electromagnetic radiation is a beam, and the width of the beam in the scanning direction is less than the width of the opening in the scanning direction.

17. The scanning operation method as claimed in claim 16, wherein: during the first scanning phase the beam is directed towards the first patterning device region; during the second scanning phase the beam is directed towards the second patterning device region; during the third scanning phase the beam is directed towards the third patterning device region.

18. The scanning operation method as claimed in claims 13 to 17, wherein the first patterning device region and the second patterning device region are separated by a first border; and the second patterning device region and the third patterning device region are separated by a second border.

19. The scanning operation method as claimed in claim 18, wherein during the first scanning phase the first border is substantially aligned with an internal edge of the first masking blade.

20. The scanning operation method as claimed in claims 13 to 19, wherein during the first scanning phase the velocities of the masking blades in the scanning direction are substantially equal to the velocity of the patterning device in the scanning direction.

21. The scanning operation method as claimed in claims 18 to 20, wherein during the third scanning phase the second border is substantially aligned with an internal edge of the second masking blade.

22. The scanning operation method as claimed in claims 13 to 21, wherein during the third scanning phase the velocities of the masking blades in the scanning direction are substantially equal to the velocity of the patterning device in the scanning direction.

23. The scanning operation method as claimed in claim 13 to 22, wherein during at least a portion of the second scanning phase the velocities of the masking blades in the scanning direction are: less than or equal to the velocity of the patterning device in the scanning direction; and/or greater than or equal to the velocity of the patterning device in the scanning direction.

24. A method of manufacturing a semiconductor device comprising the steps of: receiving a substrate with a photoresist layer and directing radiation using the scanning operation method of any of claims 13 to 23 to transfer a pattern from a mask onto the photoresist layer; and removing a portion of the photoresist layer to form the pattern over the substrate.

25. A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a support structure constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto the substrate; and a masking module according to any one of claims 1 to 12.