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    公开号:NL1035641A1
    申请号:NL1035641
    申请日:2008-06-30
    公开日:2009-01-06
    发明作者:Johannes Onvlee；Suzan Leonie Auer-Jongepier；Norbertus Josephus Martinus Van Den Nieuwelaar
    申请人:Asml Netherlands Bv；
    IPC主号:
    专利说明:

    LITHOGRAPHIC APPARATUS AND DEVICE MANUFACTURING METHOD
    BACKGROUND
    Field of the Invention
    The present invention relates to a lithographic apparatus, a lithographic system, a computer-implemented method and a computer program product to schedule the loading of a utility wafer in a flow of substrates.
    Description of the Related Art A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such a case, a patterning device, which is alternatively referred to as a mask or a reticle, may be used to generate a circuit pattern to be formed on an individual layer of the IC. This pattern can be transferred onto a target portion (e.g., including part of, one, or several dies) on a substrate (e.g., a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the "scanning" direction) while synchronously scanning the substrate parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
    In lithographic systems, a substrate track may be connected directly to the lithographic apparatus. Such substrate track comprises one or more processing units, which are configured to (automatically) process substrates. A substrate handler, for instance a substrate robot or an interface unit may be provided to transfer substrates between the substrate track and the lithographic apparatus when introducing a substrate into the lithographic apparatus, and for transferring a substrate which has been exposed, from the lithographic apparatus to the substrate track.
    In the known lithographic apparatus, the flow of substrates through the substrate track and the lithographic apparatus is designed in such a way that a substrate enters the substrate track at a particular input location, after which the substrate passes one or more processing units before being transferred to the lithographic apparatus for exposure. Thereafter, the substrate is transferred back to the substrate track where it is tasks out of the substrate track after the substrate has passed one or more processing units. During optimal production there is a continuous flow of substrates through the lithographic system.
    The present invention relates to the use of utility wafers, i.e. non-processing wafers, such as calibration wafers, dummy wafers, maintenance wafers or closing wafers. These utility wafers may be used when the presence of a wafer on a substrate support is desired for another reason than the current exposure or a pattern on a substrate to therewith avoid the use and waste of production / processing substrates.
    For instance, calibration wafers may be used for calibration or the lithographic apparatus before actual production. Dummy wafers may be used for instance during warming up and / or testing of the lithographic system. Maintenance wafers may be loaded on the substrate support used during maintenance. The use of closing wafers will be explained hereinafter. It is remarked that one or more of the functions as described with respect to calibration wafers, dummy wafers, maintenance wafers and closing wafers, may be performed by using one single type of utility wafer. For instance a "closing wafer" may also be used as a maintenance or dummy wafer.
    In a known version or a lithographic apparatus, the lithographic apparatus comprises an immersion system. In such a lithographic apparatus a liquid is between a substrate being exposed or to be exposed and a final element of the projection system, for instance a lens element. The provision of immersion liquid in this space may substantially improve exposure results. However, after exposure the substrate support may be moved away from the projection system to exchange the substrate supported on the substrate support for a new one, which when no further measures have been taken may result in that the liquid captured in the immersion space will run out of this space since the substrate is typically a hero at the bottom side of the immersion space. In different versions of the known lithographic apparatus, different solutions have been proposed to close the immersion space in order to make movement or the substrate support away from the projection system possible.
    One of these solutions, typically for a lithographic apparatus having two (or more) substrate supports is that when a first substrate supported by a first substrate support has moved away from the projection system, a second substrate support is moved simultaneously under the projection system while there is a relatively small gap between the first substrate support and the second substrate support. As a result, the liquid in the immersion space is substantial hero within this space.
    This solution works well for a continuous flow of substrates through the lithographic system. However, there may be a gap in the flow substrates. Thereby, it may be desirable that the time in which a substrate is in contact with the immersion liquid as short as possible. Furthermore, the time between exposure and the bake of substrates in the bake device or the substrate track, is critical with respect to the quality of the final product. Therefore, it is undesirable to keep an exposed substrate in the lithographic apparatus in order to avoid the liquid runs out of the immersion space in the case there is a gap in a flow of substrates or when this substrate is at the end of a batch or substrates.
    As a solution for this problem, it has been proposed to introduce so-called closing wafers into this system, which closing wafers may fill up the gaps in or at the end of a batch or substrates to be exposed by the lithographic apparatus. Such closing wafer is introduced in the lithographic system at the input location of the substrate track and follows the same path as the substrates as described above. A drawback of this solution is that when a gap comes into existence in the lithographic system itself, for instance in the substrate track, it is not possible to introduce a closing wafer in time to close the immersion space without unwanted delays, since the time required to transfer a closing wafer from the input location of the substrate track through the substrate handler to the respective substrate support is too long. Furthermore, substrates of the batch or substrates may be present between the gap in the flow of substrates and the input location of the substrate track. It is not possible to by-pass these substrates present in the lithographic system. Therefore, it is a disadvantage of the known lithographic system that the scheduling of the loading of a closing wafer cannot always be performed adequately.
    The above or similar drawbacks may also apply for the use of other utility wafers, i.e. non-processing wafers, such as calibration, dummy or maintenance wafers in the known lithographic system.
    SUMMARY
    It is desirable to provide a lithographic apparatus and / or system with the loading of a utility wafers, such as a closing wafer may be performed more adequately to increase product quality and / or throughput of the lithographic apparatus or lithographic system.
    According to an aspect of the invention there is provided a lithographic apparatus including: - an illumination system configured to condition a radiation beam; - a patterning device support 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; and - a projection system configured to project the patterned radiation beam onto a target portion of the substrate, said said lithographic apparatus comprises a utility wafer storage device for holding one or more utility wafers, a utility wafer scheduling unit configured to schedule the loading of a utility wafer in a flow of substrates in said lithographic apparatus, and a substrate handler for transferring a utility wafer between said utility wafer storage device and said substrate table.
    According to an aspect of the invention there is provided a lithographic system including: - a substrate track including one or more processing units configured to process substrates; and - a lithographic apparatus including: - an illumination system configured to condition a radiation beam; - a patterning device support 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; and - a projection system configured to project the patterned radiation beam onto a target portion of the substrate, said said lithographic apparatus comprises a utility wafer storage device for holding one or more utility wafers, a utility wafer scheduling unit configured to schedule the loading of a utility wafer in a flow of substrates in said lithographic apparatus, and a substrate handler for transferring a utility wafer between said utility wafer storage device and said substrate table, and said said substrate handler or a second substrate handler is configured to transfer a substrate between said lithographic apparatus and said substrate track.
    According to an aspect of the invention there is provided computer-implemented method of scheduling the loading of a utility wafer in a flow of substrates in lithographic apparatus, including the steps of: - detecting a gap in the flow of substrates in or towards said lithographic apparatus, - determining whether the loading of a closing wafer in said gap is desired, and - when desired, scheduling the loading of a utility wafer in said flow or substrates to fill said gap ·
    According to an aspect of the invention there is provided a computer program product to schedule the loading of a utility wafer in a flow or substrates in a lithographic apparatus, including: - software code configured to detect a gap in a flow or substrates in or towards said lithographic apparatus, - software code configured to determine whether the loading of a utility wafer in said gap is desired, and - software code configured to schedule, when desired, the loading of a utility wafer in said flow or substrates to fill said gap.
    LETTER DESCRIPTION OF THE DRAWINGS
    Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:
    Figure 1 depicts a lithographic apparatus according to an embodiment of the invention; Figure 2 schematically depicts a lithographic system according to a first embodiment of the invention; and
    Figure 3 schematically depicts a possible cause for the presence of a gap in a flow or substrates in a lithographic system.
    DETAILED DESCRIPTION
    Figure 1 schematically depicts a lithographic apparatus according to one embodiment of the invention. The apparatus includes an illumination system (illuminator) IL configured to condition a radiation beam B (eg UV radiation or any other suitable radiation), a mask support structure (eg a mask table) MT constructed to support a patterning device (eg a mask) MA and connected to a first positioning device PM configured to accurately position the patterning device in accordance with certain parameters. The apparatus also includes a substrate table (eg a wafer table) WT or "substrate support" constructed to hold a substrate (eg a resist-coated wafer) W and connected to a second positioning device PW configured to accurately position the substrate in accordance with certain parameters. The apparatus further includes a projection system (e.g. a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion C (e.g. including one or more dies) or the substrate W.
    The illumination system may include various types of optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination of, for directing, shaping, or controlling radiation.
    The mask support structure supports, i.e. bears the weight of, the patterning device. It holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device is a hero in a vacuum environment. The mask support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The mask support structure may be a frame or a table, for example, which may be fixed or movable as required. The mask support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms "reticle" or "mask" may be considered synonymous with the more general term "patterning device."
    The term "patterning device" used should be broadly interpreted as referring to any device that can be used to impart a radiation beam with a pattern in its cross-section so as to create a pattern in a target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern in the target portion of the substrate, for example if the pattern includes phase-shifting features or so called assist features. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit.
    The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography, and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted so as to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in a radiation beam which is reflected by the mirror matrix.
    The term "projection system" used should be broadly interpreted as encompassing any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term "projection lens" may also be considered as synonymous with the more general term "projection system".
    As here depicted, the apparatus is of a transmissive type (e.g., employing a transmissive mask). Alternatively, the apparatus may be of a reflective type (e.g., employing a programmable mirror array or a type referred to above, or employing a reflective mask).
    The lithographic apparatus may be of a type having two (dual stage) or more substrate tables or "substrate supports" (and / or two or more mask tables or "mask supports"). In such "multiple stage" machines the additional tables or supports may be used in parallel, or preparatory steps may be carried out on one or more tables or supports while one or more other tables or supports are being used for exposure.
    The lithographic apparatus may also be a type of at least a portion of the substrate may be covered by a liquid having a relatively high refractive index, e.g., water, so as to fill a space between the projection system and the substrate. Liquid immersion may also be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques can be used to increase the numerical aperture of projection systems. The term "immersion" as used does not mean that a structure, such as a substrate, must be submerged in liquid, but rather only means that a liquid is located between the projection system and the substrate during exposure.
    Referring to figure 1, the illuminator IL receives a radiation beam from a radiation source SO. The source and the lithographic apparatus may be separate entities, for example when the source is an excimer laser. In such cases, the source is not considered to be part of the lithographic apparatus and the radiation beam is passed from the source SO to the illuminator IL with the aid of a beam delivery system BD including, for example, suitable directing mirrors and / or a beam expander. In other cases the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, may be referred to as a radiation system.
    The illuminator IL may include an adjuster AD configured to adjust the angular intensity distribution of the radiation beam. Generally, at least the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) or the intensity distribution in a pupil plane or the illuminator can be adjusted. In addition, the illuminator IL may include various other components, such as an integrator IN and a condenser CO. The illuminator may be used to condition the radiation beam, to have a desired uniformity and intensity distribution in its cross-section.
    The radiation beam B is an incident on the patterning device (e.g., mask MA), which is a hero on the mask support structure (e.g., mask table MT), and is patterned by the patterning device. Having traversed the mask MA, the radiation beam B passes through the projection system PS, which is the beam onto a target portion C or the substrate W. With the aid of the second positioning device PW and position sensor IF (eg an interferometric device, linear encoder or capacitive sensor), the substrate table WT can be moved accurately, eg so as to position different target portions C in the path of the radiation beam B. Similarly, the first positioning device PM and another position sensor (which is not explicitly depicted in Figure 1) can be used to accurately position the mask MA with respect to the path of the radiation beam B, eg after mechanical retrieval from a mask library, or during a scan. In general, movement of the mask table MT may be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioning device PM. Similarly, movement of the substrate table WT or "substrate support" may be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the mask table MT may be connected to a short-stroke actuator only, or may be fixed. Mask MA and substrate May be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they may be located in spaces between target portions (these are known as scribe-lane alignment marks). Similarly, in situations in which more than one that is provided on the mask MA, the mask alignment marks may be located between the dies.
    The depicted apparatus could be used in at least one of the following modes: 1. In step mode, the mask table MT or "mask support" and the substrate table WT or "substrate support" are kept essentially stationary, while an entire pattern imparted to the radiation beam is projected onto a target portion C at one time (ie a single static exposure). The substrate table WT or "substrate support" is then shifted in the X and / or Y direction so that a different target portion can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. 2. In scan mode, the mask table MT or "mask support" and the substrate table WT or "substrate support" are scanned synchronously while a pattern is imparted to the radiation beam is projected onto a target portion C (ie a single dynamic exposure) . The velocity and direction of the substrate table WT or "substrate support" relative to the mask table MT or "mask support" may be determined by the (de-) magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in the non-scanning direction) or the target portion in a single dynamic exposure, whereas the length of the scanning motion has the height (in the scanning direction) of the target portion. 3. In another mode, the mask table MT or "mask support" is kept essentially stationary holding a programmable patterning device, and the substrate table WT or "substrate support" is moved or scanned while a pattern is projected onto the radiation beam a target portion C. In this mode, generally a pulsed radiation source is employed and the programmable patterning device is updated as required after each movement of the substrate table WT or "substrate support" or in between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array or a type as referred to above.
    Combinations and / or variations on the modes described above or use or entirely different modes or use may also be employed.
    Figure 2 shows schematically a first embodiment or a lithographic system according to the invention. The lithographic system comprises a lithographic apparatus LA and a substrate track ST. The substrate track ST and lithographic apparatus LA may be integrated into a single apparatus or may be two separate apparatuses combined as one system.
    The lithographic apparatus comprises a substrate handler SH. The substrate handler SH is configured to transfer substrates between the substrate track and the lithographic apparatus LA. The substrate handler SH may be a substrate robot or interface unit or any other device suitable for transferring substrates between the lithographic apparatus LA and the substrate track ST.
    In the lithographic apparatus LA, the substrates are exposed to a patterned radiation beam as discussed above.
    The substrate track ST is provided to produce a continuous flow of substrates to and from the lithographic apparatus, while a number of pre and post exposure processes are carried out with respect to these substrates. For this reason, the substrate track ST comprises a number of processing units which are each configured to process a substrate. The substrates are introduced into the substrate track at input I. Furthermore, an output O is provided for output or substrates from the lithographic apparatus after they have been processed in the lithographic system.
    In the input path of the substrate track ST, i.e. from the input I to the substrate handler SH, the substrate track comprises a coat device C. The coat device C is configured to coat a substrate with a photo-resistant or photo-sensitive coating. During exposure this coating will be exposed to a patterned radiation beam.
    In the output path of the substrate track ST, ie from the substrate handler SH to the output O, the following processing units are arranged: a bake and chill device B / C and a develop device D. The bake and chill device B / C is configured to bake and subsequently chill the substrate after exposure. The develop device D is configured to develop the coating after exposure so that the desired pattern comes into existence on the substrate. After development the substrate may leave the substrate track at the output O.
    In alternative expo of the lithographic system the substrate track ST may be provided with other or further processing units for carrying out different processes before introducing the substrate into the lithographic apparatus or after exposure in the lithographic apparatus, such as a priming device, a cleaning device , a pre-bake device, measurement of inspection devices and / or other devices for carrying out a specific treatment of the substrate.
    When a batch of substrates is exposed by the lithographic system of figure 1, the flow of substrates will generally follow the following path. The flow of substrates will be introduced into the substrate track ST at the input I. Then it will follow the input path crossing the coating device C. Then it will be transferred by the substrate handler SH to the lithographic apparatus for exposing of the substrate with a patterned beam of radiation. After exposure the substrate will be transferred back to the substrate track ST by the substrate handler SH. In the output path the substrate will be baked and chilled in the bake and chill device B / C and thereafter be developed in the develop device D. After development the substrate may leave the substrate track ST at the output O.
    The lithographic apparatus LA is of the type having two substrate supports WT and an immersion system IS between the projection system PS and a substrate support WT arranged under the projection system PS. In FIG. 2 the substrate support WT arranged under the projection system is shown in dashed lines. In an immersion system a liquid is between a substrate being exposed or to be exposed and a final element of the projection system PS, for instance a lens element. The provision of such liquid in this space may substantially improve exposure results. However, in such a system, moving the substrate support away from the projection system to exchange the substrate for a new one, results in the liquid captured in the immersion space will run out of this space when no further measures are tasks in particular in the case that the substrate is a hero at the bottom side of the immersion space.
    In the known lithographic apparatus, different solutions have been proposed to close the immersion space after exposure in order to make movement of the substrates away from the projection system without the running or immersion liquid out of the immersion space, possible.
    One of these solutions, typically for a lithographic apparatus having two (or more) substrate supports is that when a first substrate supported by a first substrate support has moved away from the projection system, a second substrate support is moved simultaneously under the projection system while there is a relatively small gap between the first substrate support and the second substrate support. As a result, the liquid in the immersion space is substantially hero within this space, first between the first substrate and the projection system and then between a second substrate and the projection system.
    This solution works well for a continuous flow of substrates through the lithographic system. Furthermore, it has been proposed to use so-called closing wafers in the lithographic system, which closing wafers may be introduced in the substrate track at the end of a batch or substrates to be exposed by the lithographic apparatus. The closing wafer which has substantially the same shape and size as a process substrate may be supported by a substrate support to close the immersion space after exposure of the batch of substrates has finished.
    This is desirable since the time in which a substrate is in contact with the immersion liquid should be as short as possible. Moreover, the time between exposure and the bake of substrates in the bake device or the substrate track, is critical with respect to the quality of the final product. At the same time, it's desirable to keep the immersion liquid in the immersion space so that exposure or a new batch or substrates can be started directly. By inserting the closing wafer, the time from end of exposure on the substrate support WT to start or bake in bake device B (PEB time) may have been kept optimal for an exposed substrate, since this substrate does not have to be used to keep the immersion space closed. Therewith, the product quality and / or throughput is thus positively influenced.
    However, there may also be a gap in the flow or a batch of substrates, as will be explained hereinafter, in which case the above solution may not always be a suffice. FIG. 3 depicts a schematic flow of substrates through a lithographic system according to an embodiment of the invention. In FIG. 3, an example of a gap in the flow of substrates caused by a maintenance action or break-down in the substrate track ST is shown affecting the flow of substrates through the lithographic system. In this example, coat device C is tasks down for maintenance or is damaged and cannot be used for a certain time. As can be seen, the substrates entering the coat device C are stopped (as represented by the dark shaded substrates) while the existing substrates in the lithographic system continue to flow through the lithographic system (as represented by the light shaded substrates). In an uncommon circumstance, all the substrates may stop in the lithographic system. Due to the coat device maintenance, a gap between substrates 1 and 2 has been created which reduces the productivity of the lithographic system.
    As can be understood from FIG. 3, substrate processing in the lithographic system loses productivity due to the gap between substrates 1 and 2 caused by a maintenance action or break-down in the substrate track ST. A gap should be understood to include a spacing between two substrates, in a part of the lithographic system, that exceeds a defined or accepted spacing between the substrates during processing in the referenced part of the lithographic system. Such spacing maybe measured, for example, in terms of time, distance and number of process positions in the lithographic system.
    Furthermore, while gaps have been described above as being caused by maintenance actions, a gap in the flow or substrate may be due to any reason. For example, a gap in the flow of substrates in at least a part of the lithographic system may be due to logistics such as untimely delivery of substrates (and other materials, e.g., masks) to the lithographic system. A gap in the flow of substrates may also be caused by unscheduled downtime or interrupts in a part of the lithographic system. A gap in the flow of substrates could also be caused by processing time and its variations in at least a part of the lithographic system such as due to system timing variations, bottlenecks (ie, a part of the lithographic system always has a gap due to the operation of another part of the lithographic system) and substrate recipes (which could lead to the shift or a bottleneck from one part of the lithographic system to another).
    When a gap in the flow of substrates comes into existence in the lithographic system, it is not possible to introduce a closing wafer in time via the substrate track of the known lithographic apparatus to close the immersion space, since the time required to transfer a closing wafer from the input location of the substrate track via the substrate handler to the respective substrate support is too long. Furthermore, substrates of the batch of substrates may be present between the gap in the flow substrates and the input location of the substrate track, or due to a maintenance action as shown in FIG 3 the closing wafer may not be able to pass the substrate track .. Therefore, it is a disadvantage of the known lithographic system that the scheduling of the loading of a closing wafer can not always be performed adequately.
    As a solution to this problem the present invention provides a closing wafer storage device CW-SD as depicted in Figure 2. The closing wafer storage device CW-SD comprises a number of closing wafers which are stored in the closing wafer storage location CW-SL . When required, a closing wafer can be transferred by the substrate handler SH from the storage location to the respective substrate table WT, as indicated by a dashed arrow in FIG. 3. In this way the gap between substrates 1 and 2 maybe filled by a closing wafer 3, and as a result the process substrates are not kept too long in the lithographic apparatus.
    When the closing wafer is no longer required in the lithographic apparatus, the closing wafer can be transferred back to the closing wafer storage device CW-SD. The closing wafer may be returned via the closing wafer CW-DC drying and cleaning device which is configured to dry and clean the closing wafer after use. When the closing wafer is three and cleaned it may be returned to the closing wafer storage location CW-SL where it can be stored until next use.
    The closing wafer storage device CW-SD is integrated in the lithographic apparatus and is placed directly next to the substrate handler SH so that a closing wafer can be directly transferred to a substrate support WT therewith by-passing all substrates possibly present in the input track or the substrate track as is clear from FIG. 3. This makes more quick and adequate loading or closing wafers possible. As a result, closing wafers can more easily be applied to fill in gaps in the flow or substrates through the lithographic system.
    The closing wafer storage device CW-SD makes subsequent use of closing wafers in the lithographic system possible without the need of introducing the closing wafers in the flow of substrates or the substrate track from input I to output O. As a result, a closing wafer is always present close to the substrate handler SH and, when required, it can easily be transferred to one of the substrate supports WT.
    The closing wafer storage device CW-SD comprises a separate input CW-I and output CW-O for introduction of a closing wafer in the lithographic system or for taking a closing wafer out of the lithographic system. In the embodiment shown the output CW-O is connected with the closing wafer drying and cleaning device CW-DC. When it is detected that the closing wafer cannot be cleaned within the closing wafer. wafer can be out of the substrate track ST via the CW-O output. New closing wafers may be introduced into the CW-SD closing wafer storage device via the CW-I closing wafer input. In alternative expiry the closing wafers may be introduced into the substrate track via input I and tasks out of the substrate track via output O. In such execution the closing wafer input CW-I and output CW-O may be omitted.
    To control the input and output of closing wafers into the lithographic apparatus, the lithographic apparatus LA comprises a closing wafer scheduling unit CW-SU. The closing wafer scheduling unit CW-SU is configured to schedule the loading of a closing wafer into the lithographic apparatus LA. Generally, the schedule unit whether or not it is desired to load a closing wafer in the flow of substrates in the lithographic apparatus, for instance by detecting the presence of a gap in the flow or substrates in the lithographic system, determining whether it is desired to fill that gap with a closing wafer, and consequently, when desired, the scheduling unit automatically actuates the respective substrate handler (s) for actual introduction of the closing wafer into the flow of substrates in the lithographic system. The gap may be detected by an interface configured to determine gaps / irregularities in the input branch or the substrate track ST.
    By providing an automatic scheduling unit it may be avoided that closing wafers are introduced too late in the flow of substrates. Furthermore, the scheduling unit may be configured to use different criteria for the determination of whether the loading or a closing wafer is required. The scheduling unit may be particularly advantageous for a lithographic system having a substrate track in which the flow of substrates can be monitored. In this way, timely the presence of a gap may be detected, and action may be tasks when required. The scheduling unit may also be used in a lithographic stand-alone apparatus, for instance for the scheduling or loading closing wafers at the end of a batch of substrates or when a gap occurs due to an error in the loading of substrates into the lithographic apparatus .
    In an embodiment, the loading or a closing wafer may for instance be based on the substrate support which is desired to be used for a process substrate, i.e. a substrate to be exposed. When for instance it is desired that only one of the two substrate supports will be used to carry a process substrate the other may be continuously loaded with a closing wafer.
    In another embodiment, the closing wafer scheduling unit CW-SU may be configured to determine whether the loading of a closing wafer in said lithographic apparatus is required on the basis of timing information of the substrate track ST and / or estimation of task durations in the substrate track unit and / or the lithographic apparatus. The closing wafer scheduling unit CW-SU may in such an application determine or estimate that a closing wafer is needed to fill a gap in the flow of substrates, for instance in or at the end or a batch of substrates. Then at the right moment the closing wafer may be introduced into the system to fill up the gap as detected by the closing wafer scheduling unit. Any suitable detection means for detection of the presence of a gap in the flow or substrates may be used. A method which for instance may be used for planning or tasks in the lithographic apparatus is disclosed in US 7,184,849, the contents of which is incorporated by reference.
    The closing wafer scheduling unit CW-SU may be further or as an alternative be configured to determine whether the loading of a closing wafer in said lithographic apparatus is required in order to optimize the time a process substrate is in contact with liquid or immersion system, to control the substrate flow in track unit by filling gaps in the substrate flow, and / or to control the substrate flow at the beginning or the end of a batch of substrates.
    The CW-SU scheduling unit typically comprises a microprocessor and appropriate software. The CW-SU scheduling unit is shown in the version of Figure 2 as a separate unit. However, the CW-SU scheduling unit may be integrated into another processing unit / control device or the substrate track ST and / or the lithographic apparatus LA, for a central processing unit and control device or the lithographic apparatus.
    Scheduling unit CW-SU usually includes software to perform the methods described above. In an embodiment, software to implement the methods described above is provided on an interface between a host system of the fab and the track and lithographic apparatus or a substrate processing system in the fab. Use can be made of existing interfaces and protocols (e.g., SECS protocols and interfaces) provided by the host system and the machines or the substrate processing system.
    More particularly, any step of the method may be executed on any general computer, such as a mainframe computer, personal computer or the like and one to more, or a part of one or more, program modules or objects generated from any programming language, such as C ++, Java, Fortran or the like. And still further, each step, or a file or object or the like implementing each step, may be executed by special purpose hardware or a circuit module designed for that purpose. For example, the invention may be implemented as a firmware program loaded into non-volatile storage or a software program loaded from or into a data storage medium as machine-readable code, such code being instructions executable by an array of logic elements such as a microprocessor or other digital signal processing unit.
    The invention may be implemented as an article of manufacture including a computer usable medium having computer readable program code means therein for executing the method steps of the invention, a program storage device readable by a machine, tangibly embodying a program or instructions executable by a machine to perform the method steps of the invention, a computer program product, or an article of manufacture including a computer usable medium having computer readable program code means therein, the computer readable program code means in said computer program product including computer readable code means for causing a computer to execute the steps of the invention. Such an article of manufacture, program storage device, or computer program product may include, but is not limited to, CD-ROMs, diskettes, tapes, hard drives, computer system memory (eg RAM or ROM) and / or the electronic, magnetic , optical, biological or other similar embodiment of the program (including, but not limited to, a carrier wave modulated, or otherwise manipulated, to convey instructions that can be read, demodulated / decoded and executed by a computer). Indeed, the article of manufacture, program storage device or computer program product may include any solid or fluid transmission medium, magnetic or optical, or the like, for failure or transmitting signals readable by a machine for controlling the operation of a general or special purpose computer according to the method of the invention and / or to structure its components in accordance with a system of the invention.
    The invention may also be implemented in a system. A system may include a computer that includes a processor and a memory device and optionally, a storage device, an output device such as a video display and / or an input device such as a keyboard or computer mouse. Moreover, a system may comprise an interconnected network or computers. Computers may equally be in stand-alone form (such as the traditional desktop personal computer) or integrated into another apparatus (such a cellular telephone).
    The system may be specially constructed for the required purposes to perform, for example, the method steps of the invention or it may include one or more general purpose computers as selectively activated or reconfigured by a computer program in accordance with the teachings stored in the computer (s). The system could also be implemented in whole or in part as a hard-wired circuit or as a circuit configuration fabricated into an application-specific integrated circuit. The invention presented is not inherently related to a particular computer system or other apparatus. The required structure for a variety of these systems will appear from the description given.
    The above embodiment of a lithographic system according to the invention comprises a closing wafer storage device configured to load closing wafers in the flow of substrates in the lithographic apparatus. A similar or the same storage device may be used for storage or other types of utility wafers such as calibration, dummy or maintenance wafers. Calibration wafers may be used for calibration or the lithographic apparatus before actual production. Dummy wafers may be used for instance during warming up and / or testing of the lithographic system. Maintenance wafers may be loaded on the substrate support used during maintenance.
    It is remarked that one or more of the functions as described with respect to calibration wafers, dummy wafers, maintenance wafers and closing wafers, may be performed by using one type of utility wafers. For instance a closing wafer may also be used as maintenance or dummy wafer. In other words, the lithographic apparatus may include a utility wafer storage device for failure or one type of utility wafers which can be used as calibration wafers, dummy wafers, maintenance wafers and / or closing wafers. However, as an alternative, it is also possible that the utility wafer storage device is used to handle different types of utility wafers.
    The scheduling unit may be configured to schedule the loading of any type of utility wafer in the flow or substrates in the lithographic apparatus.
    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 may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, liquid-crystal displays (LCDs), thin-film magnetic heads, etc. The skilled artisan will appreciate that, in the context of such alternative applications, any use of the terms "wafer" or " those "may be considered as synonymous with the more general terms" substrate "or" target portion ", respectively. The substrate referred to may be processed, before or after exposure, in for example a track (a tool that typically applies to a layer of resist to a substrate and develops the exposed resist), a metrology tool and / or an inspection tool. Where applicable, the disclosure may be applied to such and other substrate processing tools. Further, the substrate may be processed more than once, for example in order to create a multi-layer IC, so the term substrate used may also refer to a substrate that already contains multiple processed layers.
    Although specific reference may have been made above to the use of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications, for example imprint lithography, and where the context allows, is not limited to optical lithography. In imprint lithography a topography in a patterning device the pattern created on a substrate. The topography of the patterning device may be pressed into a layer or resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.
    The terms "radiation" and "beam" used include and compass all types of electromagnetic radiation, including ultraviolet (UV) radiation (eg having a wavelength of or about 365,248,193, 157 or 126 nm) and extreme ultra-violet (EUV) radiation (eg having a wavelength in the range of 5-20 nm), as well as particle beams, such as ion beams or electron beams.
    The term "lens", where the context allows, may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic and electrostatic optical components.
    While specific expired or the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may take the form of a computer program containing one or more sequences of machine-readable instructions describing a method as disclosed above, or a data storage medium (eg semiconductor memory, magnetic or optical disk) having such a computer program stored therein.
    权利要求:
    Claims (22)
    [1]
    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 or the clauses set out below. Other aspects of the invention are set out as in the following numbered clauses:
    [2]
    A lithographic apparatus comprising: - an illumination system configured to condition a radiation beam; - a patterning device support 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; and - a projection system configured to project the patterned radiation beam onto a target portion of the substrate, said said lithographic apparatus comprises a utility wafer storage device for holding one or more utility wafers, a utility wafer scheduling unit configured to schedule the loading of a utility wafer in a flow of substrates in said lithographic apparatus, and a substrate handler for transferring a utility wafer between said utility wafer storage device and said substrate table.
    [3]
    2. The lithographic apparatus of clause 1, said scheduling unit being configured to schedule the loading of a utility wafer in order to load a processing substrate on a selected substrate support.
    [4]
    3. The lithographic apparatus of clause 1, said said scheduling unit is configured to schedule the loading of a utility wafer in said lithographic apparatus on the basis of timing information of a track unit associated with said lithographic apparatus and / or estimation of task durations in said track unit or said lithographic apparatus.
    [5]
    4. The lithographic apparatus of clause 1, said said scheduling unit is configured to schedule the loading of a utility wafer in said lithographic apparatus in order to optimize: - the time a process substrate is in contact with liquid or an immersion system or said lithographic apparatus; - control of said flow substrates by filling gaps in said flow of substrates; - control of said flow of substrates at a beginning or an end or a batch of process substrates; and / or - control the post exposure delay time between end of exposure and transfer to a track unit.
    [6]
    5. The lithographic apparatus of clause 1, said scheduling unit is configured to schedule the loading of one or more utility wafers in said lithographic apparatus at the start of a new batch of substrates to warm-up and / or calibrate the lithographic apparatus before loading processing substrates.
    [7]
    6. The lithographic apparatus of clause 1, said said lithographic apparatus comprises two substrate supports and an immersion system configured to provide a liquid between a final element or said projection system and a substrate supported on one or said two substrate supports, and said said one or more utility wafers include at least one closing wafer intended to be used to close an immersion liquid space or said immersion system.
    [8]
    7. The lithographic apparatus of clause 1, said said utility wafer storage device comprises a drying unit and / or cleaning unit configured to dry and / or clean a utility wafer after use in a flow of substrates.
    [9]
    8. The lithographic apparatus or clause 1, said said utility wafer scheduling unit is integrated into a central control device or said lithographic apparatus.
    [10]
    9. The lithographic apparatus of clause 1, said said utility wafer scheduling unit comprises one or more detection device to monitor the flow of substrates in said lithographic apparatus and / or a substrate track associated with said lithographic apparatus.
    [11]
    10. A lithographic system including: - a substrate track including one or more processing units configured to process substrates; and - the lithographic apparatus of clause 1, said said substrate handler or a second substrate handler is configured to transfer a substrate between said lithographic apparatus and said substrate track.
    [12]
    11. A computer-implemented method of scheduling the loading of a utility wafer in a flow of substrates in a lithographic apparatus, including the steps of: - detecting a gap in the flow of substrates in or towards said lithographic apparatus, - determining whether the loading of a closing wafer in said gap is desired, and - when desired, scheduling the loading of a utility wafer in said flow or substrates to fill said gap.
    [13]
    12. The method of clause 11, the loading of a utility wafer is scheduled in order to load a processing substrate on a selected substrate support.
    [14]
    13. The method of clause 12, the loading of a utility wafer is determined on the basis of timing information of a track unit associated with said lithographic apparatus and / or estimation of task durations in said track unit or said lithographic apparatus.
    [15]
    14. The method of clause 11, the loading of a utility wafer is determined in order to optimize: - the time a process substrate is in contact with liquid or an immersion system or said lithographic apparatus; - the control of said flow or substrates by filling gaps in said flow or substrates; - the control of said flow of substrates at a beginning or an end or a batch of process substrates; and / or - the control of the post exposure delay time between end of exposure and transfer to a track unit.
    [16]
    15. The method of clause 11, the loading of one or more utility wafers in said lithographic apparatus is scheduled at the start of a new batch of substrates to warm-up and / or calibrate the lithographic apparatus before loading processing substrates.
    [17]
    16. A computer program product to schedule the loading of a utility wafer in a flow of substrates in a lithographic apparatus, including: - software code configured to detect a gap in a flow of substrates in or towards said lithographic apparatus, - software code configured to determine whether the loading of a utility wafer in said gap is desired, and - software code configured to schedule, when desired, the loading of a utility wafer in said flow or substrates to fill said gap.
    [18]
    17. The computer program product or clause 16, where the software code is configured to schedule the loading or a utility wafer in order to load a processing substrate on a selected substrate support.
    [19]
    18. The computer program product or clause 16, where the software code is configured to determine the loading of a utility wafer on the basis or timing information of a track unit associated with said lithographic apparatus and / or estimation or task durations in said track unit or said lithographic apparatus.
    [20]
    19. The computer program product or clause 16, where the software code is configured to determine the loading of a utility wafer in order to optimize: - the time a process substrate is in contact with liquid or an immersion system or said lithographic apparatus; - the control of said flow or substrates by filling gaps in said flow or substrates; - the control of said flow of substrates at a beginning or an end or a batch of process substrates; and / or - the control of the post exposure delay time between end of exposure and transfer to a track unit.
    [21]
    20. The computer program product or clause 16, where the software code is configured to schedule the loading of one or more utility wafers in said lithographic apparatus at the start of a new batch of substrates to warm-up and / or calibrate the lithographic apparatus before loading processing substrates.
    [22]
    A lithographic apparatus comprising: - an illumination device adapted to provide a radiation beam; - a carrier constructed to support a patterning device capable of applying a pattern in a cross-section of the radiation beam to form a patterned radiation beam; - a substrate table constructed to support a substrate; - a projection system arranged for projecting the patterned radiation beam onto a target area of the substrate, characterized in that the lithographic apparatus is provided with a substrate storage device for storing one or more substrates, a substrate planning unit adapted for scheduling loading a substrate into a stream of substrates in the lithographic apparatus, and a substrate transport device for transporting a substrate between the substrate storage device and the substrate table.
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    JP2000323393A|1999-05-12|2000-11-24|Nikon Corp|Projection aligner, data conversion device and recording medium recorded with data conversion program|
    EP1255294A4|2000-01-17|2009-01-21|Ebara Corp|Wafer transfer control apparatus and method for transferring wafer|
    EP1184725A1|2000-09-04|2002-03-06|Infineon Technologies SC300 GmbH & Co. KG|Method for adjusting a lithographic tool|
    JP2003022962A|2001-07-10|2003-01-24|Canon Inc|Exposing system, method for fabricating device, factory for producing semiconductor and method for maintaining aligner|
    DE10208165C1|2002-02-26|2003-10-02|Advanced Micro Devices Inc|Method, control and device for controlling the chemical mechanical polishing of substrates|
    JP4093462B2|2002-10-09|2008-06-04|東京エレクトロン株式会社|Substrate processing method and substrate processing apparatus|
    US6879866B2|2003-08-04|2005-04-12|Asml Netherlands B.V.|Method, computer program product and apparatus for scheduling maintenance actions in a substrate processing system|
    US7113253B2|2003-09-16|2006-09-26|Asml Netherlands B.V.|Method, apparatus and computer product for substrate processing|
    JP4524601B2|2003-10-09|2010-08-18|株式会社ニコン|Exposure apparatus, exposure method, and device manufacturing method|
    JP2005252246A|2004-02-04|2005-09-15|Nikon Corp|Exposure device and exposure method, method of controlling position and method of fabricating the device|
    EP1724815B1|2004-02-10|2012-06-13|Nikon Corporation|Aligner, device manufacturing method, maintenance method and aligning method|
    US7184849B2|2004-05-25|2007-02-27|Asml Netherlands B.V.|Method of planning tasks in a machine, method of controlling a machine, supervisory machine control system, lithographic apparatus, lithographic processing cell and computer program|
    KR20170016532A|2004-06-09|2017-02-13|가부시키가이샤 니콘|Exposure system and device production method|
    JP2007173695A|2005-12-26|2007-07-05|Sokudo:Kk|Method and system for substrate processing, and substrate processing device|
    JP2007294817A|2006-04-27|2007-11-08|Sokudo:Kk|Method, system, and apparatus for processing substrates|KR20170113709A|2009-11-09|2017-10-12|가부시키가이샤 니콘|Exposure apparatus, exposure method, exposure apparatus maintenance method, exposure apparatus adjustment method and device manufacturing method|
    US9176397B2|2011-04-28|2015-11-03|Mapper Lithography Ip B.V.|Apparatus for transferring a substrate in a lithography system|
    NL2014792A|2014-06-16|2016-03-31|Asml Netherlands Bv|Lithographic apparatus, method of transferring a substrate and device manufacturing method.|
    WO2017144343A1|2016-02-23|2017-08-31|Asml Netherlands B.V.|Method of controlling a patterning process, lithographic apparatus, metrology apparatus lithographic cell and associated computer program|
    US11036200B2|2018-10-15|2021-06-15|Coretigo Ltd.|Last resort frequency mechanism in a wireless communication system|
    法律状态:
    2009-03-02| AD1A| A request for search or an international type search has been filed|
    优先权:
    申请号 | 申请日 | 专利标题
    US82243007|2007-07-05|
    US11/822,430|US7817241B2|2007-07-05|2007-07-05|Lithographic apparatus and device manufacturing method|
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