Method and apparatus for configuring the spatial dimensions of a beam during scanning

Abstract

According to one aspect of the present invention, there is provided a method for configuring the step of scanning a photon beam or a particle beam across a pattern forming device for exposing a pattern onto a substrate, wherein the method comprises: determining a spatial resolution of a pattern correction configured to improve the quality of the exposure; and determining a spatial dimension of the beam based on the determined spatial resolution of the pattern correction.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority from European application No. 18192251.9 filed on September 3, 2018 and European application No. 19150960.3 filed on January 9, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a method and apparatus for exposing a pattern using radiation. In particular, the present invention relates to a method and apparatus for scanning a photon beam or a particle beam across a patterning device. Background Art

[0004] A lithographic apparatus is a machine configured to apply a desired pattern to a substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus can project a pattern (also commonly referred to as a "design layout" or "design") from a patterning device (e.g., a mask) onto a layer of radiation-sensitive material (resist) disposed on a substrate (e.g., a wafer).

[0005] To project a pattern onto a substrate, a lithographic apparatus can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. Typical wavelengths currently in use are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm. Compared to lithographic apparatuses using radiation having a wavelength of, for example, 193 nm, lithographic apparatuses using extreme ultraviolet (EUV) radiation with a wavelength in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on a substrate.

[0006] Low-k1 lithography can be used to process features smaller than the typical resolution limit of the lithographic apparatus. In such processes, the resolution equation can be expressed as CD = k1 × λ / NA, where λ is the wavelength of the radiation employed, NA is the numerical aperture of the projection optics in the lithographic apparatus, CD is the "critical dimension" (typically the minimum feature size printed, but in this case, half the pitch), and k1 is an empirical resolution factor. Generally, the smaller k1 is, the more difficult it is to reproduce on a substrate shapes and dimensions similar to those planned by circuit designers to achieve specific electrical functionality and performance. To overcome these difficulties, complex fine-tuning steps can be applied to the lithographic projection apparatus and / or design layout. These steps include, for example, but are not limited to, optimization of the NA, customized illumination schemes, use of phase-shifting patterning devices, various optimizations of the design layout, such as optical proximity correction (OPC, sometimes also referred to as "optical and process correction") in the design layout, or other methods generally defined as "resolution enhancement techniques" (RET). Alternatively, a tight control loop for controlling the stability of the lithographic apparatus can be used to improve the reproduction of patterns at low k1.

[0007] The radiation beam used by a lithographic apparatus may not cover the entire patterning device simultaneously. To project a pattern onto a substrate, the radiation beam may be scanned across the patterning device. The properties of the patterning device, substrate, and radiation beam may all contribute to the characteristics of the resulting pattern. Optimizing several of these properties to achieve an exposure that produces a pattern matching the intended design may include optimizing properties associated with the radiation beam itself. Summary of the Invention

[0008] According to one aspect of the present invention, there is provided a method for configuring the steps of scanning a photon beam or a particle beam across a pattern forming device for exposing a pattern onto a substrate, wherein the method comprises: determining a spatial resolution of a pattern correction configured to improve the quality of the exposure; and determining a spatial size of the beam based on the determined spatial resolution of the pattern correction.

[0009] Optionally, configuring the steps is performed in a lithographic device.

[0010] Optionally, the patterning corrections include corrections to mitigate the effects of one or more of alignment, overlay, critical dimension, dose, and focus.

[0011] Optionally, the patterning correction is determined based on one or more measurements performed on another substrate.

[0012] Optionally, the beam cross-section defines a slit at the patterning device.

[0013] Optionally, the beam passes through an exposure slit area for forming the shape of the slit.

[0014] Optionally, the spatial dimension of the beam is related to the length of the slit in a scanning direction.

[0015] Optionally, the spatial size of the beam is indirectly proportional to the spatial resolution of the patterning correction.

[0016] Optionally, according to S 2 +C 2 ≤1.1C 2 , the length S of the slit is related to the spatial resolution C of the patterned correction.

[0017] Optionally, the patterning device comprises a plurality of dies to be exposed to the substrate at a plurality of locations, wherein the spatial resolution of the patterning correction is less than a size of a die in the plurality of dies.

[0018] Optionally, the patterning device comprises a mask or a reticle.

[0019] Optionally, the spatial dimensions of the beam are controlled by a beam stop.

[0020] Optionally, the beam stop comprises a plurality of movable blades.

[0021] Optionally, the patterning device is positioned at an image plane of the beam and the beam stop is positioned in a conjugate plane of the image plane.

[0022] Optionally, variable beam shaping optics are used to adjust the spatial dimensions of the beam.

[0023] Optionally, the method further comprises scanning the beam across a patterning device to expose the pattern onto the substrate.

[0024] Optionally, the method further comprises adjusting one or more properties of the beam to apply the patterning correction during scanning of the beam across the patterning device.

[0025] Optionally, scanning the beam across the patterning device comprises moving one of the patterning device and the beam relative to the other of the patterning device and the beam.

[0026] According to another aspect of the invention, there is provided an electronic data carrier comprising instructions which, when executed on at least one processor, cause the at least one processor to control an apparatus to perform a method as described herein.

[0027] According to another aspect of the present invention, there is provided an apparatus for configuring the steps of scanning a photon beam or a particle beam across a pattern forming device for exposing a pattern onto a substrate, the apparatus comprising a processor configured to execute computer program code to perform the following method: determining the spatial resolution of a pattern correction configured to improve the quality of the exposure; and determining the spatial size of the beam based on the determined spatial resolution of the pattern correction.

[0028] Optionally, a device is provided, which is used in semiconductor manufacturing and includes the device described above.

[0029] Optionally, a lithography cell system is provided, comprising the apparatus for use in semiconductor manufacturing.

[0030] According to another aspect of the present invention, a device is provided, which is configured to obtain measurement data related to one or more properties of a pattern exposed on a substrate, determine the spatial resolution of patterning parameters of the pattern based on the measurement data, and determine the spatial dimensions of a photon beam or particle beam of a pattern forming device based on the determined spatial resolution.

[0031] Optionally, an apparatus is provided for use in semiconductor manufacturing including the apparatus described in the above paragraph.

[0032] Optionally, a lithography cell system is provided, comprising the apparatus for use in semiconductor manufacturing.

[0033] According to another aspect of the present invention, a method is provided for determining the position of a feature within a functional area on a pattern forming device configured for use in a lithography process, the method comprising determining the position of the feature within the functional area based at least in part on a dependence of spatial characteristics of a process performed after the lithography process on the position of the feature.

[0034] According to another aspect of the present invention, there is provided a patterning device comprising features positioned within the functional area using a method according to the previous aspect.

[0035] According to another aspect of the present invention, a method is provided for determining a preferred orientation of a die relative to another die on a pattern forming device configured for patterning a substrate in a process, the method comprising: determining the preferred orientation of the die based on the morphology of the substrate after performing the patterning process. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which:

[0037] - Figure 1 depicting a schematic overview of the lithographic apparatus;

[0038] - Figure 2 A schematic overview depicting the lithographic cell;

[0039] - Figure 3 Depicts a schematic representation of overall lithography, showing the collaboration between three key technologies used to optimize semiconductor manufacturing;

[0040] - Figure 4 depicts a flow chart representing steps in a method for configuring the spatial dimensions of a scanning beam; and

[0041] - Figure 5a 、 Figure 5b and Figure 5c A diagram depicting an example overlay error to be corrected.

[0042] - Figure 6a and Figure 6b The effect of varying the orientation of the die relative to adjacent dies along the scan direction on the fingerprint of the focus parameter is depicted. DETAILED DESCRIPTION

[0043] In this document, the terms "radiation" and "beam" are used to cover all types of electromagnetic radiation, including ultraviolet radiation (e.g., having a wavelength of 365 nm, 248 nm, 193 nm, 157 nm or 126 nm) and extreme ultraviolet radiation (EUV, e.g., having a wavelength in the range of about 5 nm to 100 nm).

[0044] As used herein, the terms "reticle," "mask," or "patterning device" should be broadly interpreted to refer to a general patterning device that can be used to impart a patterned cross-section to an incident radiation beam that corresponds to the pattern to be created in a target portion of the substrate. The term "light valve" may also be used in this context. In addition to typical masks (transmissive or reflective, binary, phase-shifting, hybrid, etc.), examples of other such patterning devices include programmable mirror arrays and programmable LCD arrays.

[0045] Figure 1A lithographic apparatus LA is schematically depicted. The lithographic apparatus LA comprises an illumination system (also called illuminator) IL configured to condition a radiation beam B (e.g., UV radiation, DUV radiation, or EUV radiation), a mask support (e.g., mask table) MT configured to support a patterning device (e.g., mask) MA and connected to a first positioner PM configured to accurately position the patterning device MA according to certain parameters, a substrate support (e.g., wafer stage) WT configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate support according to certain parameters, and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., comprising one or more dies) of the substrate W.

[0046] In operation, the illumination system IL receives a radiation beam from a radiation source SO, for example, via a beam delivery system BD. The illumination system IL may include various types of optical elements for directing, shaping, and / or controlling the radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, and / or other types of optical elements, or any combination thereof. The illuminator IL may be used to condition the radiation beam B to have a desired spatial and angular intensity distribution in its cross-section at the plane of the patterning device MA.

[0047] The term "projection system" PS as used herein should be broadly interpreted as covering various types of projection systems appropriate to the exposure radiation used or to other factors such as the use of an immersion liquid or the use of a vacuum, including refractive, reflective, catadioptric, anaglyphic, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof. Any use of the term "projection lens" herein should be considered synonymous with the more general term "projection system" PS.

[0048] The lithographic apparatus LA may be of a type in which 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 the space between the projection system PS and the substrate W - this is also known as immersion lithography. More information on immersion techniques is given in US6952253, which is incorporated herein by reference.

[0049] The lithographic apparatus LA may also be of a type having two or more substrate supports WT (also known as a "dual stage"). In such a "multi-stage" machine, the substrate supports WT may be used in parallel, and / or steps for preparing a substrate W for subsequent exposure may be performed on a substrate W positioned on one of the substrate supports WT while another substrate W on another substrate support WT is being used to expose a pattern on another substrate W.

[0050] In addition to the substrate support WT, the lithographic apparatus LA may also include a measurement platform. The measurement platform is arranged to hold sensors and / or cleaning devices. The sensors may be arranged to measure properties of the projection system PS or properties of the radiation beam B. The measurement platform may hold multiple sensors. The cleaning devices may be arranged to clean parts of the lithographic apparatus, such as parts of the projection system PS or parts of the system that provide immersion liquid. The measurement platform may be moved beneath the projection system PS when the substrate support WT is away from the projection system PS.

[0051] In operation, a radiation beam B is incident on a patterning device MA (e.g. a mask) held on a mask support MT and is patterned by a pattern (design layout) present on the patterning device MA. Having traversed the mask MA, the radiation beam B passes through a projection system PS which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioner PW and a position measurement system IF, the substrate support WT can be accurately moved, for example in order to position a different target portion C in the path of the radiation beam B in a focused and aligned position. Similarly, a first positioner PM and possibly a further position sensor (which is located in the substrate support WT) are provided. Figure 1 The patterning device MA may be accurately positioned relative to the path of the radiation beam B using mask alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks P1, P2 occupy dedicated target portions as shown, they may be positioned in spaces between target portions. When the substrate alignment marks P1, P2 are positioned between target portions C, they are referred to as scribe lane alignment marks.

[0052] like Figure 2 As shown in , the lithography apparatus LA may form part of a lithography cell LC (sometimes also referred to as a lithography cell or (lithography) cluster), which typically also includes equipment for performing pre-exposure and post-exposure processes on a substrate W. Conventionally, these include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, and, for example, a chill plate CH and a bake plate BK for regulating the temperature of the substrate W (e.g., for regulating the solvent in the resist layer). A substrate transporter or robot RO picks up substrates W from input / output ports I / O1, I / O2, moves the substrates between the different process equipment, and transfers the substrates W to a loading station LB of the lithography apparatus LA. The devices in the lithography cell, which are also often collectively referred to as a coating and developing system, are typically under the control of a coating and developing system control unit TCU, which itself may be controlled by a management control system SCS, which may also control the lithography apparatus LA, for example, via the lithography control unit LACU.

[0053] In order to correctly and consistently expose substrates W exposed by lithographic apparatus LA, it is desirable to inspect the substrates to measure properties of the patterned structures, such as overlay errors between subsequent layers, line thickness, critical dimensions (CDs), etc. For this purpose, an inspection tool (not shown) may be included in lithography cell LC. If errors are detected, adjustments may be made to subsequent exposures of substrates or other processing steps to be performed on substrate W, particularly if the inspection is performed before other substrates W from the same batch or lot are yet to be exposed or processed.

[0054] The inspection apparatus (which may also be referred to as a metrology apparatus) is used to determine properties of the substrate W, and in particular to determine how properties vary between different substrates W, or how properties associated with different layers of the same substrate W vary between layers. The inspection apparatus may alternatively be configured to identify defects on the substrate W, and may, for example, be part of the lithography cell LC, or may be integrated into the lithography apparatus LA, or may even be a separate device. The inspection apparatus may measure properties on a latent image (the image in the resist layer after exposure), or on a semi-latent image (the image in the resist layer after a post-exposure bake step PEB), or on a developed resist image (in which either the exposed or unexposed portions of the resist have been removed), or even on an etched image (after a pattern transfer step such as etching).

[0055] Typically, the patterning process in the lithographic apparatus LA is one of the most critical steps in the process, requiring high accuracy in the size and placement of structures on the substrate W. To ensure this high accuracy, three systems can be combined in a process such as Figure 3 . One of these systems is the lithographic apparatus LA, which is (in practice) connected to a metrology tool MT (a second system) and to a computer system CL (a third system). The key to this "holistic" environment is optimizing the collaboration between these three systems to enhance the overall process window and provide a tight control loop, thereby ensuring that the patterning performed by the lithographic apparatus LA remains within the process window. The process window defines the range of process parameters (e.g., dose, focus, overlay) within which a particular manufacturing process produces a defined result (e.g., a functional semiconductor device), typically within the range of permitted process parameter variations in the lithographic or patterning process.

[0056] The computer system CL can use (part of) the design layout to be patterned to predict which resolution enhancement technology will be used and perform computational lithography simulations and calculations to determine which mask layout and lithographic equipment settings achieve the maximum overall process window (in terms of resolution enhancement technology) for the patterning process. Figure 3Typically, the resolution enhancement technique is arranged to match the patterning possibilities of the lithographic apparatus LA. The computer system CL may also be used to detect where within the process window the lithographic apparatus LA is currently operating (e.g. using input from the metrology tool MT) to predict whether defects due to, for example, suboptimal processing may be present (e.g., at Figure 3 is depicted by an arrow pointing to “0” in the second scale SC2).

[0057] The metrology tool MT may provide input to the computer system CL to enable accurate simulations and predictions, and may provide feedback to the lithographic apparatus LA to identify, for example, possible drift in the calibration state of the lithographic apparatus LA (e.g., Figure 3 ) depicted by multiple arrows in the third scale SC3.

[0058] As mentioned above, data obtained from the metrology tool can be used to determine the properties of the image after exposure. The data can be related to properties such as overlay, critical dimension, dose, focus, etc. The data can be used to determine whether there is an exposure error based on one or more of the overlay, critical dimension, dose, or focus properties. Such errors may be caused by the settings of the equipment, or the errors may exist on the substrate, for example, due to defects on the wafer and / or the process used to prepare the wafer for exposure or the deposition of previous pattern layers. The measurement data can also be used to determine whether adjustments can be made to the exposure profile to improve future exposures of patterns on the substrate (which can be the same substrate, or a different but substantially similar substrate), for example, to remove or reduce errors detected in one or more properties. Profile adjustments, also known as corrections, can be applied to global exposure conditions across the substrate, or to more localized exposure conditions (e.g., across a smaller area on the substrate). The size of the area on the substrate requiring specific correction determines the extent to which the system can correct for measured errors in one or more parameters. Therefore, when the size of the area on the wafer requiring specific correction is expected to be small, it is desirable to increase the correction resolution. In an example, the size of the area on the substrate associated with the functional blocks of the device measures 2*2 mm 2 In order to provide corrections specific to the functional blocks, a correction resolution on the sub-mm scale is required. The achievable correction resolution may be affected by the properties of the radiation beam and may in particular depend on one or more of the size and shape of the radiation beam irradiating the patterning device.

[0059] According to the present disclosure, methods and apparatus are provided herein for determining and setting the spatial dimensions of a radiation beam used to form a pattern on a substrate via exposure of a patterning device based on a desired spatial resolution of corrections to be applied to an exposure recipe. Figure 4Steps in a method for determining the size of spatial parameters of a radiation beam are shown, which are explained in more detail below. In step 400, one or more properties of a pattern after exposure as described above are measured. In step 402, a system, such as a computer system CL, determines errors in one or more of the measured properties. In step 404, the system determines corrections to be applied to subsequent exposures to remove or reduce these errors. In step 406, the highest resolution of the identified corrections to be applied is determined. In step 408, the spatial dimensions of the radiation beam required to achieve this correction resolution are identified and set in the device. In step 410, the pattern is exposed using the set spatial dimensions of the radiation beam. The resulting exposed image can be measured by a metrology device to determine the corrections, and the process can be repeated.

[0060] The radiation beam B may be a photon beam or a particle beam. Such particles may be, for example, electrons or ions. The radiation beam B may be incident on a pattern forming device MA. After passing through the pattern forming device, the radiation beam passes through a projection system PS, by transmission or reflection, which focuses the beam onto a substrate W, which may be positioned on a substrate support table WT. In some cases, when the radiation beam B irradiates the entire pattern forming device, the pattern forming device MA and the substrate W may remain fixed relative to each other so that they are exposed simultaneously. This mode of operation may be referred to as step mode. In a single static exposure, the irradiation pattern on the pattern forming device is projected onto a target portion C of the substrate W. After exposure of the pattern, the substrate W may be shifted relative to the pattern forming device MA, and the pattern may likewise be exposed to a different target portion C' of the substrate W. In step mode, the maximum size of the target segment C that can be exposed by the radiation beam B in a single static exposure is determined by the exposure field limitation.

[0061] In some cases, the radiation beam does not irradiate the entire patterning device simultaneously, but is scanned across the patterning device to gradually expose a pattern. This mode of operation may be referred to as a scanning mode. Scanning the radiation beam B across the patterning device can be achieved by keeping the radiation beam stationary and moving the patterning device MA relative to the beam. The substrate W can be moved synchronously with the patterning device MA. The synchronous movement of the patterning device MA and the substrate W can take into account the properties of the projection system PS, such as (de)magnification and / or image inversion.

[0062] The scanning can be performed along a direction, which can be a linear direction. A linear direction perpendicular to the linear scanning direction can be referred to as a non-scanning direction. The radiation beam B can extend to cover the entire dimension of the patterning device MA in the non-scanning direction. The dimension of the radiation beam B in the scanning direction can be referred to as the length. The size and shape of the cross-section of the beam in the plane of the patterning device MA when incident on the patterning device MA can be referred to as the slit of the radiation beam B.

[0063] The shape and size of the slit can be determined within the exposure slit region. In particular, the exposure slit region can be used to determine the length of the slit. The exposure slit region can be positioned between the source of the radiation beam and the patterning device MA. Beam shaping actions that affect properties other than the slit length can be performed within and / or outside the exposure slit region. Alternatively or additionally, shaping of the radiation beam B can be performed after the radiation beam B passes through the patterning device MA. Beam shaping techniques and methods can be used to alter the shape of the slit, and the resulting slit shapes can include, for example, square, rectangular, or trapezoidal shapes. The size of the slit in the plane of the patterning device along the non-scanning direction can be in the order of centimeters, for example, 3 cm. The slit length can be in the order of millimeters, for example, 1 mm to 10 mm, or 1 mm to 20 mm. The desired control of the slit length can be in the order of millimeters, for example, selecting a slit length between 1 mm and 20 mm. The slit length can be set with a resolution of 1 mm or 0.1 mm. One or both of mechanical (e.g., beam stops) and optical (e.g., beam shaping optics) methods and tools can be used to shape the beam to define the slit. The exposure slit region can be positioned in a plane in the radiation beam path, which can be conjugate to the plane of the patterning device MA. A beam stop positioned in the exposure slit region can be used to define the slit size and shape, thereby blocking an area of ​​the beam so that only a portion of the beam cross-section is obtained, resulting in a slit of the desired shape and size at the patterning device. The beam stop can include one or more blades, which can be movable blades that can be moved in and out of at least a portion of the path of the radiation beam to block or unblock a portion of the radiation beam. The beam stop can be positioned in a conjugate plane to the patterning device MA for the radiation beam B, so that adjustments to the shape of the beam are transferred to the slit in the plane of the patterning device MA. Alternatively or in addition, beam shaping optics can be used to set the shape and size of the beam. The exposure slit region that determines the shape and size of the slit can include a three-dimensional region along a portion of the propagation path of the radiation beam B (e.g., a region containing elements of the beam shaping optics). Compared to a beam stop, beam shaping optics have the advantage of not blocking a portion of the power of the radiation beam. However, beam stops may be cheaper and easier to implement than beam shaping optics.In a lithographic apparatus as disclosed herein, the power provided by the source may be sufficient so that blocking part of the beam is acceptable and does not hinder performance of the apparatus.

[0064] The computer system CL may be configured to determine corrections to be applied to the exposure recipe based on measurements performed by the metrology system. The computer system CL may further be configured to determine a minimum spatial resolution for the corrections determined. Based on this determined minimum correction resolution, the computer system CL may determine to adjust one or more exposure parameters to achieve this resolution and instruct the associated exposure system to apply the corrections to one or more subsequent exposures. Such a system may include, for example, portions of a lithographic apparatus configured to set the dose, focus, position, direction, size and / or shape of a radiation beam. Applying adjustments to the exposures may be achieved in a number of ways, for example by using an actuator to change the shape and / or size of the radiation beam so that the corrections can be implemented during a scan of the irradiation patterning device.

[0065] As mentioned above, one of the properties that may affect the achievable correction resolution of the system is the size and shape of the radiation beam B, and specifically the size and shape of the slit. The length of the slit may affect the achievable correction resolution and mechanism. If the slit length is large, a larger portion of the substrate is exposed simultaneously, and the correction applied to the beam will affect a larger portion of the resulting exposed image. Smaller corrections applied by a slit with a larger length can be averaged over the scan. In scanning mode, the correction applied to the selected solution is convolved with the length of the slit scanned over the area to which the correction is applied during exposure. In an exemplary implementation, the computer system CL determines the minimum correction size to be applied. Based on the scan speed, the computer system CL can determine the duration of the correction to be applied to the beam, for example, 1 ms. The slit length and the scan speed further determine the duration that a point on the patterning device is exposed to a portion of the radiation beam. For a given scan speed, if the slit length is large, the exposure time of the location to be patterned on the substrate will be longer than if the slit length were smaller at the same scan speed. For larger slit lengths, the total exposure time can be, for example, 10 ms or 30 ms. In the example case described here, a 1 ms correction applied to a location can be averaged over the remaining 9 ms of exposure of that location to the rest of the radiation beam B, and the correction will not be successfully implemented. Moreover, during the 1 ms of applying the correction, this correction is already applied to the area on the substrate irradiated by the slit, which increases with the length. Therefore, increasing the slit length negatively impacts the correction resolution due to the longer averaging effect of the scan, and thereby increases the area over which the correction is applied.

[0066] As disclosed herein, the resolution of the convolution correction is preferably close to the resolution of the correction C to be applied. This can be achieved by setting the slit length S so that S 2 +C 2 <aC 2is achieved, where a is a scalar number greater than and close to 1. In the example, the correction dimension C is 1 mm, and the maximum permissible value of a is set to 1.1. This selected value of a determines the corresponding maximum permissible slit length aC under those conditions. 2 -C 2 >S 2 , so for the determined correction C = 1 mm, S must be less than to comply with the requirement set by the chosen a. For a known setting of the values ​​C and S, the lowest value of a obtained can be considered as a relative measure for the extent to which the correction C for the slit length S in question is achievable.

[0067] Reducing the slit length means that a smaller area of ​​the substrate to be patterned is exposed at any one time, meaning that corrections applied to the beam irradiate a smaller area. Therefore, corrections applied to the beam are applied to a smaller area. Furthermore, if the beam length is smaller, the length of time that any one location on the substrate is exposed is reduced, meaning that corrections can be applied for a shorter amount of time and are not averaged out over the rest of the beam scan. Corrections to the radiation beam can be applied to a smaller area on the patterned substrate over a shorter exposure area and for a shorter duration, thereby increasing the resolution at which corrections can be applied.

[0068] As described herein, some embodiments relate to the selection of slit length, which can affect the productivity and quality of the resulting exposed image. Advantages of shorter slit lengths include the ability to apply higher-resolution corrections, resulting in greater accuracy in exposure. Advantages of larger slit lengths, compared to shorter lengths, include the potential for higher productivity due to the simultaneous exposure of a larger area of ​​the pattern. Another advantage of larger lengths is the ability to average dose variations within the slit, resulting in more uniform exposure and increased dose control.

[0069] The effect of slit length variation will now be described in more detail with respect to an example for correcting overlay errors, as Figure 5a 、 Figure 5b and Figure 5c As shown in FIG. The horizontal axis represents the scanning direction of the beam along the pattern forming device. The vertical axis represents the overlay error of the exposed pattern on the substrate in the scanning direction. Both axes are expressed in arbitrary units. Figure 5a In the example, the overlay error is constant along the scan direction. To correct for this constant error, a constant adjustment along the scan direction can be applied to the matching scheme. Because the same adjustment is applied at every point along the scan direction, the ability to perform this correction is not limited by the slit length. In fact, a larger slit length and averaging of dose variations within the slit can be beneficial for increasing throughput.

[0070] exist Figure 5bIn , the example overlay error is not constant along the scan direction, and instead possesses a periodicity, varying linearly along the scan direction. As explained above, the slit length will affect the resolution of the correction. Figure 5c It also shows that the overlay error varies linearly along the scanning direction. Figure 5b , Figure 5c The example error has a high rate of change in the overlap error, which means that a high-resolution correction is required to address this situation. Figure 5c The maximum slit length of the correction can be achieved less than Figure 5b The maximum slit length of the correction. Figure 5b and Figure 5c The example error of has a linearly varying profile. However, the methods and apparatus disclosed herein deal with the spatial dimensions of the correction to be applied to the exposure. Therefore, other nonlinear error profiles can also be handled using the methods and apparatus described above.

[0071] The structures deposited on the substrate during the lithographic exposure may have dimensions in the nanometer or micrometer range. To increase the production throughput of the lithographic process, multiple of these structures may be positioned on the same patterning device MA and patterned during the same exposure. A structure or collection of structures on the patterning device MA that is separate from other structures on the patterning device MA may be referred to as a die. An example size of a die on the patterning device is 10 mm x 10 mm (100 mm x 10 mm). 2 ), but the die size can be larger or smaller than these dimensions and can have a square, rectangular, or other shape. Multiple dies can be arranged in an array on the patterning device. Each die includes a pattern that can be independent of the other dies on the patterning device. Because the structures contained within a die can be different from the structures of other dies, the correction to be applied can be different between dies. To enable intra-die correction, that is, to apply different corrections to different dies, the slit length can be at least small enough to achieve a correction resolution that is smaller than the size of the die in the scan direction.

[0072] Alternatively or in addition to providing a slit length that is small enough to enable intra-die correction, it is proposed to improve the correction force of process parameters across the substrate by configuring a patterning device used in patterning the substrate.

[0073] Typically, the patterning device comprises a plurality of functional areas comprising (product) features.

[0074] The functional regions may be associated with a certain functionality required for the semiconductor device to implement the following regions, such as first and second functional regions providing (cache) memory, a third functional region including a graphics processing unit (GPU), and a fourth functional region including logic for controlling the memory.

[0075] Alternatively, the functional region may be associated with a die region that is a product feature of a whole functional semiconductor device (a layer). Each functional region is repeatedly provided to the patterning device. The patterning device may then include, for example, six functional regions (die); three dies in the scan direction across the patterning device and two dies in a direction perpendicular to the scan direction.

[0076] In many cases, the distribution of features across a functional area affects the characteristics of processes performed after the exposure step of the patterning device. For example, the density of features across a functional area can vary along the scan direction, significantly affecting the substrate topography after undergoing etching, deposition, and polishing (CMP) steps. Topography is the height profile of the substrate across the exposure field of a substrate that has undergone a patterning process (performed by a lithographic apparatus).

[0077] exist Figure 6a In , an example of three identical dies oriented in an end-to-end configuration along the scan direction is given. Each die has an associated feature layout that results in a focus profile along the scan direction, as indicated by the expected focus values ​​associated with the six measurement points (points in the graph) (per die). Figure 6a In the depicted example, the left side point of each die is associated, for example, by the perimeter structure of the die, and the five points immediately adjacent to the perimeter are associated with the cell structure of the die.

[0078] from Figure 6a It is clearly visible that a steep gradient of the focus profile occurs between the dies. For example, within a translation as small as 1 mm along the scan direction, the focus step between Die 1 and Die 2 can be as large as 100 nm. In particular, for 3D NAND manufacturing processes involving the deposition, etching, and polishing of thick layers, the focus steps can have considerable amplitude.

[0079] Where the focus steps are too large and / or occur over too small a spatial scale, the lithographic apparatus used in subsequent lithographic process steps may not be equipped to accurately control the focus of the substrate while scanning the patterning device.

[0080] It is recommended to configure the patterning device so that the location of features within the functional area (which is the area of ​​the semiconductor device defined by the die or function) is selected based on the expected spatial scale of the characteristics of the process performed after exposure of the patterning device. Specifically, the location of the features within the functional area is selected so that focus step, overlay, edge placement error (EPE), critical dimension (CD), or dose are expected to occur at a spatial scale sufficient to be corrected by the control device of the lithography process.

[0081] Where the functional areas are dies, efficient positioning of features may be achieved by rotating or mirroring an existing layout of features for a series of one or more dies.

[0082] Figure 6b Depicts the expected focus profile if the second die (die 2) has a rotated (180 degrees around center) or mirrored feature layout relative to die 1 and die 3. Figure 6b It follows that there are no longer any focus steps between the dies, only focus steps within each die (due to, for example, the difference between the peripheral structure and the cell structure). Furthermore, compared to the initial focus steps associated with the initial feature layout of Die 2 ( Figure 6a ), the spatial scale along which the focus steps between die 2 and die 3 are generated (in the scanning direction) has been doubled. This doubling effectively reduces the gradient of the focus variation between the dies, which makes the focus steps easier to correct by a focus control system included in the scanning lithographic apparatus.

[0083] In an embodiment, the patterning device comprises a plurality of functional regions, characterized in that a layout of features associated with a first functional region is mirrored and / or rotated compared to a layout of features associated with a second functional region adjacent to the first functional region.

[0084] So far, given the example (specifically, Figure 6a and Figure 6b ) discloses a specific embodiment of the general concept of distributing features over at least one functional area based on an expected dependency of spatial characteristics of subsequent processes on the locations of the features.

[0085] The distribution of features (e.g., the locations of features) across the functional regions is typically defined during the design process of the patterning device. Empirical or physical models of process steps known in the art of semiconductor manufacturing, such as polishing, etching, and deposition of layers, can be used to predict the spatial characteristics (e.g., the configuration of feature locations) of a given feature layout. After determining the locations of features to be included in at least one functional region, the patterning device can be manufactured by providing the features to a substrate of the patterning device (typically using a photolithographic process).

[0086] Furthermore, the distribution of features across at least one functional region can be determined in conjunction with the selection of the spatial dimensions of the beam used in patterning the substrate. The positioning of the features across the functional region can be performed, for example, based on an existing layout of features across the functional region and updated only if it is determined that the spatial resolution of the patterning correction is not sufficiently high for providing semiconductor devices produced using the photolithography process. The updated positions of the features can then be determined, for example, based on a rotation of the existing layout of features so that the spatial resolution of the spatial characteristics of processes performed subsequent to the photolithography process does not exceed the correction capabilities.

[0087] In an embodiment, the location of features within the functional area on the patterning device is based at least in part on the spatial resolution of the patterning correction and spatial characteristics of a process performed after exposing the pattern onto the substrate.

[0088] In an embodiment, the location of a feature on a functional area on a patterning device configured for use in a lithographic process is determined based at least in part on a dependency of a spatial characteristic of a process performed after the lithographic process on the location of the feature.

[0089] In an embodiment, the patterning device comprises a plurality of functional areas, each functional area representing an individual die.

[0090] In an embodiment, the position of a feature within a functional region is determined by a rotation of the layout of features associated with another functional region on the patterning device.

[0091] In an embodiment, the rotation is a 180 degree rotation about the center of the functional area.

[0092] In an embodiment, the location of features within a functional region is determined by mirroring the layout of features associated with another functional region on the patterning device.

[0093] In an embodiment, the mirroring is defined relative to an axis of symmetry of another functional area.

[0094] In an embodiment, the axis of symmetry is perpendicular to a scanning direction of a lithographic apparatus used in a lithographic process.

[0095] In an embodiment, the process performed subsequent to the lithographic process is a second lithographic process, and the spatial characteristic is the ability to control parameters associated with the second lithographic process.

[0096] In an embodiment, the parameter associated with the second lithography process is one of: focus, critical dimension, overlay, edge placement error, dose.

[0097] In an embodiment, the process performed subsequent to the photolithography process is an etching or deposition process, and the spatial characteristic is a topography of the substrate after undergoing the photolithography process and the etching or deposition process.

[0098] In an embodiment, based on the determined positions of the features on the at least one functional area, the patterning device is manufactured according to any suitable embodiment for determining said positions.

[0099] In an embodiment, the patterning device comprises features positioned within the functional area using a method of manufacturing a patterning device.

[0100] In an embodiment, determining a preferred orientation of a die relative to another die on a patterning device configured for use in a process for patterning a substrate comprises determining the preferred orientation of the die based on a topography of the substrate after performing the process for patterning the substrate.

[0101] In an embodiment, the patterning device is configured for use in a process for producing 3D NAND devices.

[0102] In an embodiment, the topography is associated with a height profile across one or more die regions on the substrate.

[0103] In an embodiment, the preferred orientation of the die is associated with the height profile of the substrate, which can be corrected by available focus control mechanisms of the patterning process.

[0104] Further embodiments of the invention are disclosed in the following list of numbered aspects:

[0105] 1. A method of configuring the step of scanning a photon beam or a particle beam across a patterning device for exposing a pattern onto a substrate, the method comprising:

[0106] determining a spatial resolution of a patterned correction configured to improve the quality of the exposure; and

[0107] The spatial dimensions of the photon or particle beam are determined based on the determined spatial resolution of the patterning correction.

[0108] 2. The method of clause 1, wherein configuring the steps is performed in a lithographic apparatus.

[0109] 3. The method of clause 2, wherein the patterning corrections include corrections to mitigate the effects of one or more of alignment, overlay, critical dimension, dose, and focus.

[0110] 4. The method according to any preceding aspect, wherein the patterning correction is determined based on one or more measurements performed on another substrate.

[0111] 5. The method of any preceding clause, wherein the beam cross-section defines a slit at the patterning device.

[0112] 6. The method according to clause 5, wherein the photon beam or particle beam passes through an exposure slit area for forming the shape of the slit.

[0113] 7. A method according to any one of clauses 5 or 6, wherein the spatial size of the photon beam or particle beam is related to the length of the slit in the scanning direction.

[0114] 8. The method of clause 1, wherein the spatial size of the photon beam or particle beam is indirectly proportional to the spatial resolution of the patterned correction.

[0115] 9. The method according to aspect 7, wherein the 2 +C 2 ≤1.1C 2 , the length S of the slit is related to the spatial resolution C of the patterned correction.

[0116] 10. The method of any preceding clause, wherein the patterning device comprises a plurality of dies to be exposed to the substrate at a plurality of locations, and wherein a spatial resolution of the patterning correction is smaller than a size of a die in the plurality of dies.

[0117] 11. The method of any preceding clause, wherein the patterning device comprises a mask or a reticle.

[0118] 12. The method according to any preceding clause, wherein the spatial dimensions of the photon or particle beam are controlled by a beam stop.

[0119] 13. The method of clause 12, wherein the beam stop comprises a plurality of movable blades.

[0120] 14. A method according to clause 13, wherein the patterning device is positioned at an image plane of the beam, and wherein the beam stop is positioned in a conjugate plane of the image plane.

[0121] 15. A method according to any preceding aspect, wherein variable beam shaping optics are used to adjust the spatial dimensions of the beam.

[0122] 16. A method according to any preceding clause, further comprising scanning the beam across the patterning device to expose the pattern onto the substrate.

[0123] 17. The method of clause 16, further comprising adjusting one or more properties of the beam to apply a patterning correction during scanning of the beam across the patterning device.

[0124] 18. A method according to clause 16 or 17, wherein scanning the beam across the patterning device comprises moving one of the patterning device and the beam relative to the other of the patterning device and the beam.

[0125] 19. An electronic data carrier comprising instructions which, when executed on at least one processor, cause the at least one processor to control an apparatus to perform the method according to any one of clauses 1 to 18.

[0126] 20. An apparatus for configuring the step of scanning a photon beam or a particle beam across a patterning device for exposing a pattern onto a substrate, the apparatus comprising a processor configured to execute computer program code to:

[0127] determining a spatial resolution of a patterned correction configured to improve the quality of the exposure; and

[0128] The spatial dimensions of the photon or particle beam are determined based on the determined spatial resolution of the patterning correction.

[0129] 21. An apparatus for use in semiconductor manufacturing comprising the apparatus according to clause 20.

[0130] 22. A lithocell system comprising the apparatus according to clause 21 for use in semiconductor manufacturing.

[0131] 23. A device configured to:

[0132] obtaining measurement data related to one or more properties of a pattern exposed on a substrate;

[0133] determining a spatial resolution of patterning parameters of the pattern based on the measurement data; and

[0134] The spatial dimensions of the photon or particle beam of the patterning device are determined based on the determined spatial resolution.

[0135] 24. An apparatus for use in semiconductor manufacturing comprising the apparatus of clause 23.

[0136] 25. A lithocell system comprising the apparatus of clause 24 for use in semiconductor fabrication.

[0137] 26. A method for determining the position of a feature within a functional area on a pattern forming device configured for use in a lithography process, the method comprising: determining the position of the feature within the functional area based at least in part on the dependence of spatial characteristics of a process performed subsequent to the lithography process on the position of the feature.

[0138] 27. The method of clause 26, wherein the patterning device comprises a plurality of functional regions, each functional region representing an individual die.

[0139] 28. A method according to clause 26 or 27, wherein the position of a feature within a functional area is determined by rotating the layout of features associated with another functional area on the patterning device.

[0140] 29. The method of clause 28, wherein the rotation is a 180 degree rotation about the center of the functional area.

[0141] 30. A method according to clause 26 or 27, wherein the position of the features within the functional area is determined by mirroring the layout of features associated with another functional area on the patterning device.

[0142] 31. A method according to clause 30, wherein the mirroring is defined relative to an axis of symmetry of another functional area.

[0143] 32. A method according to clause 31, wherein the axis of symmetry is perpendicular to a scanning direction of a lithographic apparatus used in a lithographic process.

[0144] 33. A method according to any of clauses 26 to 32, wherein the process is a second lithographic process and the spatial characteristic is the ability to control parameters associated with the second lithographic process.

[0145] 34. The method of clause 33, wherein the parameter is one of: focus, critical dimension, overlay, edge placement error, dose.

[0146] 35. The method of any one of clauses 26 to 32, wherein the process is an etching or deposition process, and the spatial characteristic is the topography of the substrate after undergoing a photolithography process and an etching or deposition process.

[0147] 36. A patterning device comprising features positioned within a functional area using the method of any one of clauses 26 to 35.

[0148] 37. A method of manufacturing a patterning device, the method comprising the step of applying features in functional areas on a patterning device, wherein the features are positioned according to the method of any one of clauses 26 to 35.

[0149] 38. A device manufacturing process comprising the step of patterning a substrate using the patterning device according to clause 36.

[0150] 39. A method for determining a preferred orientation of a die relative to another die on a patterning device configured for use in a process of patterning a substrate, the method comprising determining the preferred orientation of the die based on the topography of the substrate after performing the patterning process.

[0151] 40. The method of clause 39, wherein the patterning device is configured for use in a process for producing a 3D NAND device.

[0152] 41. The method of clause 39, wherein the topography is associated with a height profile across one or more die regions on the substrate.

[0153] 42. The method of clause 41, wherein the preferred orientation of the die is associated with a height profile that can be corrected by available control mechanisms of the patterning process.

[0154] 43. A method according to any one of Aspects 1 to 25, further comprising: configuring the pattern forming device by positioning features within a functional area on the pattern forming device based at least in part on the spatial resolution of the patterning correction and / or the spatial characteristics of a process performed after exposing the pattern to the substrate.

[0155] 44. A pattern forming device comprising a plurality of functional regions, wherein the layout of features associated with a first functional region is mirrored and / or rotated compared to the layout of features associated with a second functional region adjacent to the first functional region.

[0156] 45. The patterning device of clause 44, wherein the layout of features associated with the first functional area is mirrored relative to an axis of symmetry of the first functional area compared to the layout of features associated with the second functional area.

[0157] 46. ​​The patterning device of clause 44, wherein the layout of features associated with a first functional area is rotated about a center of the first functional area compared to the layout of features associated with a second functional area.

[0158] 47. The patterning device of any one of clauses 44 to 46, wherein the functional area is a die.

[0159] 48. The patterning device of any one of clauses 44 to 47, wherein the patterning device is configured for use in a 3D NAND manufacturing process.

[0160] 49. The method according to aspect 1, wherein the patterning device is a patterning device according to aspect 36 or any one of aspects 44 to 48.

[0161] The methods and apparatus described herein may be used in the lithographic fabrication of integrated circuits, which may be, for example, 3D NAND structures.

[0162] The methods described herein may be in the form of instructions contained on an electronic data carrier. The electronic data carrier may comprise hardware or a signal that is downloadable and transmittable via a wired or wireless connection medium.

[0163] Although specific reference may be made herein to the use of lithographic apparatus in IC manufacturing, it should be understood that the lithographic apparatus described herein may have other applications. Possible other applications include the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads, and the like.

[0164] Although specific reference may be made herein to embodiments of the present invention in the context of lithographic apparatus, embodiments of the present invention may be used in other apparatus. Embodiments of the present invention may form part of mask inspection equipment, metrology equipment, or any apparatus that measures or processes an object such as a wafer (or other substrate) or a mask (or other patterning device). These apparatuses may generally be referred to as lithographic tools. Such lithographic tools may use vacuum conditions or ambient (non-vacuum) conditions.

[0165] Although specific reference may be made above to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention is not limited to optical lithography and may be used in other applications such as imprint lithography, where the context permits.

[0166] Although specific embodiments of the present invention have been described above, it will be appreciated that the present invention may be practiced in other ways than those described. The above description is intended to be illustrative and not restrictive. Therefore, those skilled in the art will appreciate that modifications may be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. A method for configuring a photon beam or a particle beam used in scanning exposure of a pattern on a pattern forming device onto a substrate, the method comprising: determining a spatial resolution of a patterning correction configured to improve a quality of the scanning exposure; and determining a spatial size of the photon or particle beam based on the determined spatial resolution of the patterned correction, Wherein the beam cross section defines a slit at the patterning device and the spatial dimension of the photon or particle beam is associated with the length of the slit in the direction of the scanning exposure. The method according to claim 1 , wherein the configuring is performed in a lithographic apparatus.

3. The method of claim 2, wherein the patterning corrections include corrections to mitigate the effects of one or more of alignment, overlay, critical dimension, dose, and focus.

4. The method of claim 1, wherein the patterning correction is determined based on one or more measurements performed on another substrate. 5 . The method according to claim 1 , wherein the photon beam or particle beam passes through an exposure slit area for forming a shape of the slit.

6. The method of claim 1, wherein the spatial size of the photon or particle beam is indirectly proportional to the spatial resolution of the patterned correction.

7. The method according to claim 1, wherein , the length S of the slit is related to the spatial resolution C of the patterning correction.

8. The method of claim 1, wherein the patterning device comprises a plurality of dies to be exposed to the substrate at a plurality of locations, and wherein the spatial resolution of the patterning correction is less than a size of one of the plurality of dies.

9. The method of claim 1, wherein the patterning device comprises a mask.

10. The method of claim 1, wherein the patterning device comprises a reticle.

11. The method of claim 1, wherein the spatial dimensions of the photon or particle beam are controlled by a beam stop.

12. The method according to claim 1, further comprising: The patterning device is configured by positioning features within functional regions on the patterning device based at least in part on the spatial resolution of the patterning correction.

13. An electronic data carrier comprising instructions which, when executed on at least one processor, cause the at least one processor to control a device to perform the method according to claim 1.

14. An apparatus for configuring a photon beam or a particle beam used in scanning exposure of a pattern on a pattern forming device onto a substrate, the apparatus comprising a processor configured to execute computer program code to perform the following method: determining a spatial resolution of a patterning correction configured to improve the quality of the scanning exposure; and determining a spatial size of the photon or particle beam based on the determined spatial resolution of the patterned correction, Wherein the beam cross section defines a slit at the patterning device and the spatial dimension of the photon or particle beam is associated with the length of the slit in the direction of the scanning exposure.

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