Handling system for microlithographic photomasks, inspection system and processing system having a handling system

Abstract

This invention relates to a loading and unloading system for a photomask (17), comprising an articulated robotic arm (26) and an alignment device (30). The alignment device (30) is designed to rotate the photomask (17) held by the alignment device (30) about a vertical axis (51) during a first movement process and to flip the photomask about a horizontal axis (52) during a second movement process. This invention also relates to an inspection system having a loading and unloading system and a processing system having a loading and unloading system.

Description

Technical Field

[0001] The present invention relates to a loading and unloading system for a lithography mask, a processing system having a loading and unloading system, and an inspection system having a loading and unloading system. Prior Art

[0002] Photomasks are used in lithographic projection exposure equipment to create integrated circuits with extremely small structures. The photomask, illuminated by extremely short-wavelength deep ultraviolet or extreme ultraviolet radiation (DUV or EUV radiation), is imaged onto the lithographic object, transferring the mask structure to the lithographic object.

[0003] To ensure high-quality images created on lithographic objects, photomasks must be dimensionally accurate and unaffected by contamination. For this reason, photomasks are inspected before initial use or during maintenance procedures and, if necessary, post-processed, cleaned, or calibrated. In this context, various inspection and processing systems are used, to which the photomasks are transferred for the necessary steps. These steps are often performed in a vacuum.

[0004] For example, contamination can arise from outgassing from components surrounding the photomask, which can lead to contaminants being deposited on the photomask surface. This is particularly problematic in areas of the photomask where structures for subsequent wafers are located. Contamination risks can also arise from foreign particles, such as those originating from contact points on the photomask. Since the photomask is typically made of plastic, it has a relatively high outgassing rate. Plastic particles decompose under the influence of ultraviolet light, forming carbon, which can reduce the reflectivity of the photomask and optical components.

[0005] Before the reticle is introduced into the inspection / processing system, it must be correctly aligned. To do this, the reticle is rotated about the vertical axis and / or flipped about the horizontal axis, depending on its initial state. This is followed by a movement process to introduce the reticle into the inspection or processing system.

[0006] It is known to use a six-axis robot with all the necessary degrees of freedom for mobile processing, including reticle translation and alignment. However, the spatial conditions around inspection and processing systems are often very limited, so the available space for a six-axis robot is insufficient. In particular, the mounting height of the assembly carrying the reticle is often very high, making it impossible to deposit the reticle in such a confined space.

[0007] Complex systems are also known in which different system components are used to move different parts of the process. For example, a first system component may be responsible for translational movement in the horizontal plane, a second system component may be responsible for rotation about a vertical axis, and a third system component may be responsible for flipping the reticle about a horizontal axis. Summary of the Invention

[0008] The object of the present invention is to provide a loading and unloading system, an inspection system, and a processing system that avoids these disadvantages. This object is achieved by the features of the independent claims. Advantageous embodiments are described in detail in the dependent claims.

[0009] A lithography mask handling system according to the present invention includes an articulated robot arm and an alignment device. The alignment device is designed to rotate a mask held by the alignment device about a vertical axis during a first movement process and to flip the mask about a horizontal axis during a second movement process. The designation of the first and second movement processes is independent of any restrictions regarding the temporal order of the movement processes.

[0010] The present invention has realized that this allows to reduce complexity relative to known systems. With respect to the type of joints required for the handling system according to the present invention, it is easier to design the joints so that the mask can be handled under vacuum conditions without outgassing.

[0011] The articulated robotic arm may include a robotic arm base, a first articulated arm attached to the robotic arm base via a first rotation joint, a second articulated arm attached to the first articulated arm via a second rotation joint, and a third articulated arm attached to the second articulated arm via a third rotation joint.

[0012] A rotary joint is a joint that precisely provides rotation about a single axis. This restriction to one degree of freedom allows for simple joint packaging, which is advantageous for preventing outgassing. One or more rotary joints may be vacuum-tightly packaged, thereby preventing particles generated within the rotary joint from escaping into the surrounding environment. The axes of the first, second, and third rotary joints of the articulated robot arm may be aligned parallel to one another, allowing the end of the third rotary joint to move within the XY plane by actuating the rotary joint. The XY plane may be a horizontal plane.

[0013] Each of the rotary joints may have a joint driver, so that actuation of the joint driver can change the position of the rotary joint. The joint driver can be controlled by a control signal.

[0014] The articulated robot arm may include a linear actuator to modify the height position of the third articulated arm in the Z direction. The linear actuator may be positioned between the robot arm base and the first articulated arm. Changing the height position of the first articulated arm also changes the height position of the second articulated arm, which is supported by the first articulated arm. The linear actuator is also limited to a single degree of freedom of movement, which is advantageous for preventing outgassing. The linear actuator may be vacuum-tightly encapsulated to prevent the generation of particles due to friction.

[0015] The alignment device may include a holding mechanism for the photomask. The holding mechanism may be designed to hold the photomask in the holding mechanism regardless of alignment relative to gravity. In one embodiment, the holding mechanism includes a first clamping jaw and a second clamping jaw. The holding mechanism may include an actuator that allows for setting a distance between the first clamping jaw and the second clamping jaw. In a first state of the holding mechanism, the distance between the clamping jaws may be greater than the distance between two opposing ends of the photomask to be held. In a second state of the holding mechanism, the clamping jaws may abut against both ends of the photomask, thereby holding the photomask between the clamping jaws.

[0016] The holding mechanism can have an initial position in which the holding mechanism is designed to grip and lift the photomask on the structure. The photomask on the structure can be aligned horizontally. The holding device can be coupled to two opposing edges of the photomask to lift the photomask.

[0017] Inspection and handling systems are often designed to require the reticle to be introduced in a defined alignment. Assuming a reticle with a roughly rectangular shape, there are four positions where the reticle is rotated 90°, with the edges of the reticle aligned parallel to the X-direction and parallel to the Y-direction. To bring the reticle into the correct one of the four possible rotational positions, it may be necessary to rotate the reticle about the Z-axis.

[0018] Correct alignment also involves the correct side of the reticle pointing upward. If the reticle is placed on the structure in the wrong alignment, it must be flipped 180° around the horizontal axis to align it correctly. Therefore, there are eight different possibilities for aligning the reticle held in the holding mechanism.

[0019] The handling system may include a sensor mechanism for capturing the alignment of the reticle. The reticle may have markings that allow for alignment identification. For example, if one of the four corners of the reticle has a marking, this marking can clearly determine the four possible rotational positions of the reticle. Similarly, based on a marking, it can be determined whether the reticle needs to be flipped. The sensor mechanism can be designed to capture the alignment of the reticle based on such markings. For example, the sensor mechanism may include an optical sensor that responds to a pair of markings.

[0020] The sensor mechanism can be a component of the alignment device. This is advantageous in that information about the photomask held in the alignment device can be directly obtained through the sensor mechanism.

[0021] The alignment device may include a first rotary drive for rotating the holding mechanism about a vertical axis. The vertical axis is defined as an axis at right angles to the plane of the reticle. The first rotary drive preferably has exactly one degree of freedom, in particular rotational freedom about the axis. The first rotary drive may be vacuum-tightly packaged. The first rotary drive may have four rotational positions, each position differing by 90°. Multiple control commands for appropriately controlling the first rotary drive may be stored in a control unit of the handling system. The first rotary drive may include a fine-tuning tool that allows various rotational positions to be preset with high precision. The alignment device can then be adjusted directly via a drive shaft, rather than through fine mechanical adjustments. The axis of the first rotary drive may be at right angles to the plane spanned by the reticle held in the holding mechanism. The axis of the first rotary drive may intersect the center of the reticle, so that the reticle is balanced relative to the axis. Advantageously, the low torque of the first rotary drive is sufficient to rotate the holding mechanism holding the reticle.

[0022] The first rotary actuator may include a motor having a rotor and a stator. The motor may be a stepper motor. The stator may be mounted on a structure of the alignment device. The first rotary actuator may include an encoder that provides information about the rotational position of the motor. The first rotary actuator forms an actuator for a handling system with a single degree of freedom.

[0023] The rotor and the holding mechanism can be directly coupled or a structural component of the alignment device holding the holding mechanism, so that the holding mechanism rotates directly with the rotor. If the motor shaft of the first rotary drive is aligned parallel to the vertical axis about which the photomask rotates, a smaller motor shaft footprint is advantageous for lower installation height. Generally speaking, a smaller shaft footprint is better achieved with an external rotor motor than with an internal rotor motor. A larger motor diameter is acceptable as an alternative.

[0024] A transmission can also be arranged between the motor of the first rotary drive and the holding mechanism. The motor shaft can then be aligned differently from the axis about which the holding mechanism rotates. For example, the two shafts may be at an angle of 90°. If the motor shaft is aligned horizontally, an inner rotor motor with a smaller diameter than an outer rotor motor may be advantageous.

[0025] A low installation height is a specific requirement for the handling of photomasks according to the present invention. Only when the low installation height requirement is met is it possible to deposit the photomask within the space or to guide the photomask through an opening defined upward and downward by adjacent structures. The only available space that allows the photomask to be introduced into the space and deposited is the space between adjacent structures. The holding mechanism may include a frame support to which are attached two clamping elements designed to clamp the photomask disposed in a horizontal plane when viewed from a lateral direction. To this end, the horizontal extent of the frame support with these clamping elements may be greater than the extent of the photomask in the relevant direction. The directional specifications defined with respect to the installation height relate to the alignment of the photomask with the holding mechanism.

[0026] A smaller vertical distance between the light mask and the frame supports facilitates a lower installation height. The vertical distance between the light mask and the frame supports can be less than 6 mm, preferably less than 2 mm, and more preferably less than 1 mm. This specification relates to the maximum vertical clearance between the light mask and the frame supports.

[0027] A smaller mounting height of the frame bracket is advantageous. For example, the mounting height of the frame bracket can be less than 12 mm, preferably less than 8 mm, and more preferably less than 6 mm. This specification relates to the frame bracket not protruding laterally beyond the portion of the light mask.

[0028] The frame holder with multiple clamping elements can be designed to hold the photomask regardless of its alignment relative to the force of gravity of the unit formed by the frame holder, clamping elements, and photomask. To this end, it is usually necessary to clamp the photomask around so that the clamping elements cover the portion that protrudes beyond the photomask on the side facing away from the frame holder. The portion of the clamping elements that protrudes beyond the photomask can have a vertical extent of no more than 3 mm, and preferably no more than 2 mm. If these vertical extents of the clamping elements differ, the specification relates to the clamping element with the largest extent. The clamping elements can have a surface with significant static friction in the area where they abut the photomask. For example, the surface can consist of PEEK.

[0029] The first rotary drive may be configured such that the frame bracket is disposed between the first rotary drive and the light shield relative to the vertical direction. The installation height of the first rotary drive may be less than 40 mm, preferably less than 25 mm, and more preferably less than 10 mm.

[0030] In an alternative embodiment, a lower installation height can be achieved by arranging the first rotary drive to the side of the photomask. This requires transferring the rotational motion from the first rotary drive to the rotational motion of the photomask. This transfer can be accomplished, for example, using a toothed belt or a metal belt.

[0031] The components of the handling system to be introduced into a confined space can be installed at a height corresponding to the maximum vertical reach from the clamping element to the first rotary drive. Specifically, the frame component attached to the first rotary drive can be fastened so that it does not protrude vertically beyond the rotary drive. The frame component can form a load-bearing connection between the light mask and the articulated arm of the articulated robot. The installed height of these components can be less than 100 mm, preferably less than 80 mm, more preferably less than 60 mm, and even more preferably less than 40 mm. The installed height, including the first rotary drive and extending to the closest surface of the light mask, can be less than 30 mm, preferably less than 20 mm, and more preferably less than 15 mm.

[0032] The alignment device may include a second rotary drive for tilting the holding mechanism about a horizontal axis. The horizontal axis refers to an axis aligned parallel to the plane of the reticle. The second rotary drive preferably has exactly one degree of freedom, in particular a rotational degree of freedom about an axis. The second rotary drive may be vacuum-tightly packaged. The second rotary drive may have a first rotational position and a second rotational position rotated 180° relative to the first rotational position. A plurality of control commands for appropriately controlling the second rotary drive may be stored in a control unit of the handling system. The second rotary drive may have a fine adjustment mechanism that allows various rotational positions to be preset with high precision. The alignment device can then be adjusted directly via the drive shaft, rather than through fine mechanical adjustments. The axis of the second rotary drive may lie within the plane spanned by the reticle held in the holding mechanism. The axis of the second rotary drive may intersect the center of the reticle, so that the reticle is balanced relative to the axis. Advantageously, the low torque of the second rotary drive is sufficient to tilt the holding mechanism holding the reticle.

[0033] The second rotary drive may include a motor having a rotor and a stator. The motor may be a stepper motor. The second rotary drive may include an encoder that provides information about the motor's rotational position. The stator may be secured to the alignment device structure. The rotor and the securing mechanism may be directly coupled, or the stator may be a structural component of the alignment device that secures the securing mechanism, so that the securing mechanism rotates directly with the rotor.

[0034] A low installation height for the alignment device is generally desirable. If the motor axis is parallel to the horizontal axis about which the optic rotates, and the motor has a small diameter, this helps reduce the installation height. In this case, the motor is advantageously an inner rotor motor, which generally allows for a smaller diameter than an outer rotor motor. A greater axial extent is also acceptable as an alternative.

[0035] A transmission device can also be arranged between the motor of the second rotary drive and the holding mechanism. The motor shaft can then be aligned differently from the axis about which the holding mechanism rotates. For example, there could be a 90° angle between the two shafts. If the motor shafts are aligned perpendicularly, it may be advantageous for an outer rotor motor to have a smaller axial extent than an inner rotor motor.

[0036] The first rotary drive can be fixed on a structural component of the alignment device that is flipped by the second rotary drive. Alternatively, the second rotary drive can be fixed on a structural component of the alignment device that rotates along with the first rotary drive.

[0037] The handling system may include a control unit, which is designed to control the plurality of rotary drives of the alignment device and / or the plurality of joint drives of the rotary joints via control signals.

[0038] The articulated robotic arm and the alignment device may be separate components of the handling system. The alignment device may be arranged in a fixed position so that if the articulated robotic arm is actuated, the alignment device remains in a fixed position relative to the robotic arm base of the articulated robotic arm.

[0039] The third articulated arm of the articulated robot arm can be implemented as an end effector, designed to remove the photomask from the alignment device and / or transfer the photomask to the alignment device. The third articulated arm can have a supporting element, on which the photomask carried by the third articulated arm is attached. The articulated robot arm can be designed to transfer the photomask to the holding mechanism of the alignment device and, after the photomask has been properly aligned by the alignment device, retrieve the photomask from the holding mechanism of the alignment device.

[0040] To transfer the reticle to the holding mechanism, the articulated robotic arm can be used to horizontally displace the reticle until it is horizontally positioned above or below the holding mechanism. The linear motor of the articulated robotic arm can be used to drive the reticle upward or downward until it is positioned at a height that allows it to be held by the holding mechanism. The third articulated arm can then be displaced to the side, allowing the alignment device to align the reticle without colliding with the various components of the articulated robotic arm. Transfer from the holding mechanism to the articulated robotic arm can then be performed. The articulated robotic arm can then transfer the reticle to the processing chamber or to the antechamber of the processing chamber of the inspection or processing system.

[0041] In an alternative embodiment, the articulated robot arm and the alignment device are components of a handling system designed as a single device. The alignment device can be attached to a third articulated arm of the articulated robot arm. Thus, when the articulated robot arm is actuated, the position of the alignment device changes with the third articulated arm.

[0042] The rotation axis of the alignment device can be aligned parallel to the longitudinal direction of the third articulated arm. This can be the rotation axis of the second rotary drive for turning the light mask 180°.

[0043] Before the holding mechanism of the loading and unloading system removes the photomask, the photomask can be placed on a support platform. The holding mechanism, along with the jointed robotic arm of the loading and unloading system, can be displaced horizontally until it is in a position capable of holding the photomask. Subsequently, the holding mechanism can be moved upward via the linear actuator of the jointed robotic arm to lift the photomask from the support platform.

[0044] The alignment device can be actuated to properly align the photomask. The articulated robotic arm can then be actuated to transfer the photomask to a processing chamber of the inspection system or processing system, or to an anteroom of the processing chamber. A carrier on which the photomask is placed can be disposed in the processing chamber or the anteroom of the processing chamber. To this end, the articulated robotic arm is actuated to move the holding mechanism along with the photomask to a position above the carrier. The linear actuator of the articulated robotic arm is then actuated to move the holding mechanism downward, placing the photomask on the carrier.

[0045] The carrier platform may have a self-centering effect, allowing a reticle placed on the carrier platform to automatically be centered relative to the carrier platform. The carrier platform may include multiple wedge-shaped surfaces, along which the reticle slides when it is lowered onto the carrier platform. The wedge-shaped surfaces may be designed so that the lateral edges of the reticle contact the wedge-shaped surfaces. The wedge-shaped surfaces may have surfaces made of a material that facilitates sliding. The wedge-shaped surfaces may have a horizontal centering effect. The carrier platform may have one wedge-shaped surface for each of the four lateral edges of the reticle. The carrier platform may have two wedge-shaped surfaces for each of the four lateral edges of the reticle. The retaining mechanism may be designed so that when the reticle is placed on the carrier platform, the frame of the retaining mechanism can be positioned between two wedge-shaped surfaces on the lateral edges of the reticle. The retaining mechanism may be designed so that when the reticle is placed on the carrier platform, multiple clamping elements for clamping the reticle can be positioned between two wedge-shaped surfaces disposed on the lateral edges of the reticle.

[0046] The support structure can be designed so that the support structure can be displaced laterally beneath the reticle in each of the eight possible alignments of the reticle, so that the reticle can be placed on the support structure and released from the holding mechanism of the alignment device. Subsequently, the support structure and the alignment device can be spatially separated from each other. For these steps, the alignment device can be moved relative to the support structure, or the support structure can be moved relative to the alignment device.

[0047] The present invention also relates to an inspection system for lithography masks, comprising a loading and unloading system according to the present invention and a processing chamber for performing mask inspection. The loading and unloading system is designed to transfer the mask to the processing chamber or an antechamber of the processing chamber.

[0048] The present invention also relates to a processing system for lithography masks, comprising a loading and unloading system according to the present invention and a processing chamber for performing processing steps on the mask. The loading and unloading system is designed to transfer the mask to the processing chamber or an antechamber of the processing chamber. Simple diagram description

[0049] The present invention will be described below by way of example based on advantageous embodiments with reference to the accompanying drawings. In the drawings:

[0050] Figure 1 shows an inspection system according to the present invention;

[0051] Figure 2 shows an embodiment of the loading and unloading system according to the present invention;

[0052] Figure 3 shows a different view of the loading and unloading system of Figure 2;

[0053] Figure 4 shows multiple components of the loading and unloading system of Figures 2 and 3;

[0054] Figure 5 shows a view according to Figure 4 in another state of the loading and unloading system;

[0055] Figure 6 shows the mask on the carrier stage;

[0056] Figure 7 shows an alternative embodiment of the present invention according to a view of Figure 4;

[0057] Figure 8 shows an alternative embodiment of the loading and unloading system according to the present invention;

[0058] Figure 9 shows a component of the loading and unloading system of Figure 8;

[0059] Figure 10 shows a schematic diagram of a processing system according to the present invention; and

[0060] FIG. 11 shows an alternative embodiment of a processing system according to the present invention. Implementation Method

[0061] Generally, the lithography mask 17 is configured for use in a lithography projection exposure apparatus (not shown). In the lithography projection exposure apparatus, the mask 17 is irradiated with deep ultraviolet radiation or extreme ultraviolet radiation (DUV radiation / EUV radiation) to image the structure formed on the mask 17 onto the surface of a lithography object in the form of a wafer. The wafer is coated with a photoresist that reacts to the EUV radiation. An inspection system is used to verify that the mask meets requirements and is free of contamination. A processing system is used to post-process the mask or correct errors in the mask.

[0062] A handling system according to the invention is used to pick up a lithography mask 17 in an inspection system or a processing system, align it correctly, and put it down again.

[0063] FIG1 schematically illustrates an exemplary embodiment of an inspection system. A reticle 17 is configured in the inspection system such that an EUV beam path 15 emitted from an EUV radiation source 14 is directed to the reticle 17 via an illumination system 16. Illumination system 16 is used to shape the EUV radiation into a beam that illuminates an inspection field on the surface of the reticle 17 with uniform brightness. Reticle 17 can have, for example, a rectangular shape with an edge length between 100 mm and 200 mm. Using an XY positioning mechanism 19, the reticle can be moved in the XY plane to bring different inspection fields of the reticle into the region of the EUV beam path.

[0064] After being reflected by the reticle 17, the EUV beam path 15 continues through a projection lens 22 to an EUV camera 23 having an image sensor 24. The projection lens is used to image the inspection field of the reticle 17 onto the image sensor 24 of the EUV camera 23. The EUV radiation source 14, the illumination system 15, the reticle 17, the projection lens 22, and the EUV camera 23 are arranged in a processing chamber 18. During operation of the measurement apparatus, the processing chamber is under negative pressure.

[0065] The inspection system includes a transfer transition chamber 20, into which the photomask 17 to be inspected is inserted under atmospheric pressure. Before the photomask 17 is removed from the transfer transition chamber 20, the transfer transition chamber 20 is brought to a vacuum corresponding to that of the processing chamber 18.

[0066] The transfer of the reticle 17 to the transfer transition chamber 20 is performed via a handling system 21 located in the inspection system's antechamber 25. The handling system 21 is designed to ensure the correct alignment of the reticle 17. There are eight possible alignments for the reticle 17: four positions resulting from a 90° rotation about the vertical axis 51 and four corresponding positions resulting from a 180° flip about the horizontal axis 52. When the reticle 17 is inserted into the antechamber 25, it can assume any of the eight possible alignments. Only one of these eight possible alignments is inspected by the inspection system.

[0067] The handling system 21 identifies the alignment of the reticle 17 in the antechamber 25 and, if necessary, properly aligns the reticle 17 by appropriately rotating it about the vertical axis 51 (Z axis) and flipping it about the horizontal axis 52. The reticle 17 is then transferred to the processing chamber 18 of the inspection system.

[0068] 2 , the handling system 21 includes an articulated robot 26 having a robot base 34, a first articulated arm 27, a second articulated arm 28, and a third articulated arm 29. The first articulated arm 27 is attached to the robot base 34 via a first rotary joint 31. The second articulated arm 28 is attached to the first articulated arm 27 via a second rotary joint 32. The third articulated arm 29 is attached to the second articulated arm 28 via a third rotary joint 33. The third articulated arm 29 carries an alignment device 30. The axes of the rotary joints 31, 32, and 33 are vertically aligned (see FIG. 3 ), so that actuation of the rotary joints 31, 32, and 33 allows the alignment device 30 carried by the third articulated arm 29 to be positioned differently within the XY plane. The articulated robot 26 also includes a linear actuator 35 formed between the robot base 34 and the first articulated arm 27 and can be used to modify the height position of the alignment device 30.

[0069] According to FIG4 , the alignment device 30 includes a holding mechanism 39 having two grippers 40 between which the photomask 17 is held. The grippers 40 can be brought closer together to clamp the photomask 17 or moved away from each other to release the photomask 17 via an actuator (e.g., a Lorentz actuator). The holding mechanism 39 is connected to the third articulated arm 29 of the articulated robot 26 via a second rotary drive 38, a structural component 37, and a first rotary drive 36. Actuating the first rotary drive 36 rotates the photomask 17 about the vertical axis. The first rotary drive 36 can be driven to four different angular positions, each spaced 90° apart.

[0070] Second rotary drive 38 can be used to rotate structural assembly 37, along with first rotary drive 36 and reticle 17, 180° about horizontal axis 52. By using two rotational positions of second rotary drive 38 and four rotational positions of first rotary drive 36, alignment device 30 provides a total of eight different alignments for reticle 17. FIG. 5 illustrates one of the possible alignments, in which, relative to the state shown in FIG. 4 , reticle 17 has been rotated 180° about horizontal axis 52 and 90° about vertical axis 51.

[0071] Figure 6 shows a support platform 41 on which the alignment device 30 can place the mask 17 after the mask 17 has been properly aligned. The support platform 41 includes a plurality of support structures 42 that define the dot-shaped areas on which the mask 17 rests. In an alternative embodiment, the support platform has inclined support surfaces, the distance between which corresponds to the width of the mask 17. Opposite edges of the mask rest on the support surface of the support platform. The edges of the mask 17 can be chamfered to create planar contact between the edges of the mask and the support surface of the support platform.

[0072] In the alternative exemplary embodiment of FIG7 , alignment device 30 includes two sensor mechanisms 43 that can be used to determine the current alignment of reticle 17. Sensor mechanisms 43 include optical sensors that respond to markings attached to reticle 17. Measurements from sensor mechanisms 43 allow the alignment of reticle 17 to be unambiguously determined from eight possible alignments. Thus, reticle 17 can be transferred to alignment device 30 in any alignment without requiring alignment device 30 to continue further processing the information.

[0073] FIG8 shows an exemplary embodiment in which the alignment device 30 is separate from the articulated robot arm 26. The alignment device 30 is located on the base via a housing 46. A gripper 40 is used to hold the reticle 17 on a frame support 39, which is attached to the housing 46 via a first rotary actuator 36. A second rotary actuator 38 is formed between the gripper 40 and the frame support 39, which can be used to flip the reticle 17 180° about a horizontal axis. By actuating the first rotary actuator 36, the frame support 39 and the reticle 17 rotate together about a vertical axis. The first rotary actuator 36 is designed to drive to four positions, each position differing by 90°. Thus, the alignment device 30 provides eight different alignments into which the reticle 17 can be positioned.

[0074] In the use of an end effector, the articulated robot 26 includes a receiving arm 44 ( FIG. 9 ) attached to the third articulated arm 29 of the articulated robot 26 . An upward-facing carrying protrusion 45 is attached to the receiving arm 44. To remove the reticle 17 from the carrying platform 41 , the third articulated arm 29 of the articulated robot 26 is moved until the carrying protrusion 45 is positioned below the reticle 17. The linear actuator 35 is used to lift the reticle 17 from the carrying platform 41 . The receiving arm 44 is moved to the position shown in FIG. 8 , where it is positioned between the two supports of the frame support 39 of the alignment device 30 and the reticle 17 is positioned between the jaws 40 of the holding mechanism 30 . The jaws 40 are moved so that the reticle 17 is held between the jaws. The articulated robot 26 retracts the receiving arm 44, allowing the alignment device 30 to be actuated without colliding with other components of the articulated robot 26 .

[0075] The reticle 17 is properly aligned by actuating the first rotary drive 36 and the second rotary drive 38. The reticle 17 is then removed from the alignment device 30 and transferred to the next carrier 41 of the inspection system using the corresponding process. The reticle 17 is now properly aligned for inspection in the processing chamber of the inspection system.

[0076] As shown in FIG8 , the frame bracket 39 of the alignment device 30 is designed so that each time the reticle 17 is aligned, the receiving arm 44 can be driven from the side into the available space so that the receiving arm 44 occupies a position below the reticle 17 .

[0077] 10 schematically shows a processing chamber 47 of a processing system for a DUV mask. An electron beam is used to process the mask in the processing chamber 47 for writing a specific structure on the substrate of the mask.

[0078] The photomask 17 to be processed can be retrieved via the carrier 41. The loading and unloading system 21 lifts the photomask 17 from the carrier 41. The alignment device 30 is used to properly align the photomask 17. The photomask is then transferred to an antechamber 48 of the processing chamber 47 through the actuation of the articulated robot 26. From the antechamber 48, the photomask can be transferred to the processing chamber 47.

[0079] 11 , the loading and unloading system 21 is disposed between the transition chamber 49 and the processing chamber 47 . The loading and unloading system 21 is designed to transfer the photomask 17 directly to the processing chamber 47 .

[0080] In all exemplary embodiments, each actuator of the handling system according to the invention has exactly one degree of freedom. This allows for perfect encapsulation of the actuator and prevents outgassing, even under the vacuum conditions in which the handling system operates.

[0081] 14: EUV radiation source 15: EUV beam path 16: Lighting system 17: Mask 18: Processing chamber 19:XY positioning mechanism 20: Transmission transition chamber 21: Loading and unloading system 22: Projection lens 23:EUV Camera 24: Image sensor 25:Front room 26: Joint Robotic Arm 27: First joint arm 28: Second joint arm 29: Third joint arm 30: Alignment device 31: First rotary joint 32: Second rotary joint 33: The third rotary joint 34: Robotic arm base 35: Linear drive 36: First rotary driver 37: Structural components 38: Second rotary drive 39: Holding mechanism / frame bracket 40: Holding mechanism / clamping claw / clamping element 41: Carrying platform 42: Bearing structure / support structure 43:Sensor mechanism 44: receiving arm 45: Load-bearing protrusion / support structure 46: Shell 47: Processing chamber 48:Front room 49: Transition chamber 51: Vertical axis 52: horizontal axis

Claims

1. A loading and unloading system for a photomask (17), comprising: an articulated robotic arm (26) and an alignment device (30) configured to rotate the photomask (17) held by the alignment device (30) about a vertical axis (51) during a first movement process and to flip the photomask about a horizontal axis (52) during a second movement process; wherein the alignment device (30) is configured such that a support structure (42, 45) is movable laterally below the photomask (17) in each of eight possible alignments of the photomask (17).

2. The loading and unloading system as claimed in claim 1, wherein the articulated robotic arm (26) includes a robotic arm base (34), a first articulated arm (27) attached to the robotic arm base (34) via a first rotary joint (31), a second articulated arm (28) attached to the first articulated arm (27) via a second rotary joint (32), and a third articulated arm (29) attached to the second articulated arm (28) via a third rotary joint (33).

3. The loading and unloading system as described in claim 1 or 2 further includes a first rotary drive (36) for rotating the photomask (17) about the vertical axis (51), the first rotary drive (36) having exactly one degree of freedom.

4. The loading and unloading system as described in claim 3, wherein the axial range of the first rotary drive (36) does not exceed 40 mm.

5. The loading and unloading system as described in claim 3, wherein the first rotary drive (36) has a vacuum-tight enclosure.

6. The loading and unloading system as described in claim 1 further includes a second rotary drive (38) for rotating the photomask (17) about the horizontal axis (52), the second rotary drive (38) having exactly one degree of freedom.

7. The loading and unloading system as claimed in claim 1, wherein the alignment device (30) includes a holding mechanism designed to hold the photomask (17) unaffected by gravity alignment.

8. The loading and unloading system as claimed in claim 7, wherein the holding mechanism includes a frame support (39), and wherein the maximum distance between the photomask (17) held by the holding mechanism and the frame support (39) is less than 6 mm.

9. The loading and unloading system as claimed in claim 8, wherein the holding mechanism includes a clamping element (40), and wherein the clamping element (40) protrudes no more than 3 mm beyond the photomask (17) held by the holding mechanism on the side opposite to the frame support (39).

10. The loading and unloading system as claimed in claim 7, wherein the center of the vertical axis (51) intersects the photomask (17) held in the holding mechanism.

11. The loading and unloading system as claimed in claim 7, wherein the horizontal axis (52) lies in the plane spanned by the photomask (17) held in the holding mechanism.

12. The loading and unloading system as described in claim 1 further includes a sensor mechanism (43) for capturing the alignment of the photomask (17).

13. An inspection system for a photomask, comprising a loading and unloading system (21) and a processing chamber (18) for inspecting the photomask (17), the loading and unloading system (21) being designed to transfer the photomask (17) to the processing chamber (18) or to the anterior chamber (25) of the processing chamber (18), and the loading and unloading system being designed as described in any one of claims 1 to 12.

14. A processing system for a photomask (17) comprising a loading / unloading system (21) and a processing chamber (47) for performing processing steps on the photomask (17), the loading / unloading system (21) being designed to transfer the photomask (17) to the processing chamber (47) or to a pre-chamber (48) of the processing chamber (47), and the loading / unloading system being designed as described in any one of claims 1 to 12.

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