Field-to-field correction using superimposed targets

Abstract

A metrology system may include a controller coupled to a metrology tool. The controller may receive a metrology target design, the metrology target design including at least one first feature formed by exposing a first exposure field on a sample using a lithography tool and at least one second feature formed by exposing a second exposure field on the sample using the lithography tool, wherein the second exposure field overlaps the first exposure field at a location of a metrology target on the sample. The controller may further receive metrology data associated with the metrology target fabricated according to the metrology target design, determine one or more fabrication errors during fabrication of the metrology target based on the metrology data, and generate correction terms based on the one or more fabrication errors to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on 35 U.S.C. §119(e) and claims U.S. Provisional Application No. 62 / 782,594, filed on December 20, 2018, entitled “OVERLAY MARK DESIGN AND ALGORITHMIC APPROACHES FOR IMPROVING OVL MODELED FIELD TERMS AND CORRECTING SCANNER ERRORS,” invented by Enna Leshinsky-Altshuller, Inna Tarshish-Shapir, Mark Ghinovker, Diana Shaphirov, Guy Ben Dov, Roie Volkovich and Chris Steely, the entire text of which is incorporated herein by reference. Technical Field

[0003] The present invention relates generally to superposition metrology measurements, and more particularly to superposition metrology measurements that provide field-to-field correction terms. Background Art

[0004] Semiconductor fabrication lines typically incorporate metrology measurements at one or more points during the fabrication process to monitor and control the fabrication of features on a particular sample and / or across multiple samples. For example, a typical fabrication process includes fabricating multiple dies distributed across the surface of a sample (e.g., a semiconductor wafer, etc.), wherein each die includes multiple patterned material layers that form device components. Each patterned layer may be formed by a series of steps (including material deposition, photolithography, and etching) to produce the pattern of interest. In addition, the photolithography tools (e.g., scanners, steppers, etc.) used in the exposure step have a field of view that is substantially smaller than the sample size, so that each sample layer is exposed using many exposure fields distributed across the sample. Therefore, it may be desirable to monitor and control field-to-field errors associated with the size and setting of the exposure fields used to expose each layer across the sample, and to monitor and control overlay errors associated with features on different sample layers within each exposure field, which increases the number of metrology targets on the sample and reduces fabrication throughput. However, typical metrology systems require separate targets and / or measurement techniques for overlay metrology and field-to-field metrology. It is therefore desirable to provide systems and methods for performing high throughput overlay metrology and field-to-field metrology. Summary of the invention

[0005] According to one or more illustrative embodiments of the present invention, a metrology system is disclosed. In one illustrative embodiment, the system includes a controller communicatively coupled to a metrology tool. In another illustrative embodiment, the controller receives a metrology target design, the metrology target design including at least one first feature formed by exposing a first exposure field on a sample using a lithography tool and at least one second feature formed by exposing a second exposure field on the sample using the lithography tool. In another illustrative embodiment, the second exposure field partially overlaps the first exposure field and further overlaps the first exposure field on the sample at a location of a metrology target. In another illustrative embodiment, the controller receives metrology data associated with the metrology target fabricated according to the metrology target design. In another illustrative embodiment, the controller determines one or more fabrication errors during fabrication of the metrology target based on the metrology data. In another illustrative embodiment, the controller generates one or more correction terms based on the one or more fabrication errors to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps.

[0006] According to one or more illustrative embodiments of the present invention, a pattern mask is disclosed. In one illustrative embodiment, the pattern mask includes one or more device pattern elements located in a device area of ​​the pattern mask. In another illustrative embodiment, the pattern mask includes a first set of metrology pattern elements located in a first target area. In another illustrative embodiment, the pattern mask includes a second set of metrology pattern elements located in a second target area. In another illustrative embodiment, the first target area and the second target area are arranged on opposite sides of the device area along a first direction. In another illustrative embodiment, the first set of metrology pattern elements and the second set of metrology pattern elements are configured to form at least a portion of a metrology target on a sample when the pattern mask is exposed on the sample using a first exposure field and a second exposure field, the first exposure field and the second exposure field being distributed so that the first target area of ​​the first exposure field overlaps the second target area of ​​the second exposure field on the sample at the location of the metrology target.

[0007] According to one or more illustrative embodiments of the present invention, a metrology method is disclosed. In one illustrative embodiment, the method includes exposing a first exposure field on a sample using a lithography tool to form at least one first feature of a metrology target. In another illustrative embodiment, exposing a second exposure field on the sample using the lithography tool to form at least one second feature of the metrology target, wherein the second exposure field partially overlaps the first exposure field, and wherein the second exposure field overlaps the first exposure field at a location of the metrology target on the sample. In another illustrative embodiment, the method includes generating metrology data associated with the metrology target using a metrology tool. In another illustrative embodiment, the method includes determining one or more manufacturing errors during manufacturing of the metrology target based on the metrology data. In another illustrative embodiment, the method includes generating one or more correction terms based on the one or more manufacturing errors to adjust one or more manufacturing parameters of the lithography tool in one or more subsequent lithography steps.

[0008] It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not necessarily limit the invention as claimed. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the general description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Those skilled in the art may better understand the numerous advantages of the present invention with reference to the accompanying drawings, in which:

[0010] Figure 1A is a conceptual diagram illustrating a production system according to one or more embodiments of the present invention;

[0011] Figure 1B is a conceptual diagram illustrating a lithography subsystem according to one or more embodiments of the present invention;

[0012] Figure 1C is a block diagram of a metering subsystem according to one or more embodiments of the present invention;

[0013] Figure 2 is a conceptual top view of a sample illustrating a plurality of overlapping exposure fields associated with a plurality of photolithography steps performed by a photolithography subsystem associated with fabrication of a particular sample layer in accordance with one or more embodiments of the present invention;

[0014] Figure 3 is a conceptual top view of a double-layer field-sensitive stacking target according to one or more embodiments of the present invention;

[0015] Figure 4A is suitable for forming according to one or more embodiments of the present invention Figure 3A top view of a pattern mask of a field-sensitive superposition target illustrated in FIG.

[0016] Figure 4B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Figure 4A The pattern mask uses overlapping exposure fields along two orthogonal directions to produce a field-sensitive superposition target;

[0017] Figure 5A is suitable for forming according to one or more embodiments of the present invention Figure 3 A top view of a pattern mask of a design of a field-sensitive superposition target including four grid regions in which portions of first layer target features and portions of second layer target features are located in each grid region as illustrated in FIG.

[0018] Figure 5B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Figure 5A The pattern mask in the embodiment uses partially overlapping exposure fields along two orthogonal directions to produce a field-sensitive superposition target;

[0019] Fig. 6A is suitable for forming according to one or more embodiments of the present invention Figure 3 A top view of a pattern mask of a box-in-box design of a field-sensitive overlay target illustrated in FIG. 1 , in which portions of first-layer target features and portions of second-layer target features are located in a series of nested boxes;

[0020] Figure 6B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig. 6A The pattern mask in the method utilizes partially overlapping exposure fields to produce a field-sensitive overlay target;

[0021] Fig. 7A is suitable for forming according to one or more embodiments of the present invention Figure 3 A top view of a pattern mask of a "ruler" type design of a field-sensitive superposition target illustrated in FIG. 1 , in which portions of first layer target features and portions of second layer target features are located in a series of nested comb patterns;

[0022] Figure 7B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig. 7A The pattern mask in the method utilizes partially overlapping exposure fields to produce a field-sensitive overlay target;

[0023] Fig. 8A is suitable for forming according to one or more embodiments of the present invention Figure 3A top view of a pattern mask of an AIMid design of a field-sensitive overlay target illustrated in FIG. 1 , in which first layer target features and second layer target features are staggered;

[0024] Figure 8B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig. 8A The pattern mask in the method utilizes partially overlapping exposure fields to produce a field-sensitive overlay target;

[0025] Fig.9A is suitable for forming according to one or more embodiments of the present invention Figure 3 A top view of a pattern mask of an AIMid design of a field-sensitive superposition target illustrated in FIG. 1 , in which first layer target features and second layer target features overlap to form a cross pattern;

[0026] Fig. 9B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig.9A The pattern mask in the method utilizes partially overlapping exposure fields to produce a field-sensitive overlay target;

[0027] Fig.10 is a conceptual top view of a single-layer field-sensitive overlay target according to one or more embodiments of the present invention;

[0028] Fig.11A is suitable for forming according to one or more embodiments of the present invention Fig.10 A top view of a pattern mask of a field-sensitive superposition target illustrated in FIG.

[0029] Fig. 11B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig.11A The pattern mask in the embodiment uses partially overlapping exposure fields along two orthogonal directions to produce a field-sensitive superposition target;

[0030] Fig.12 is a conceptual top view of a single-layer field-sensitive overlay target according to one or more embodiments of the present invention;

[0031] Fig.13A is a top view of a pattern mask suitable for forming first layer features according to one or more embodiments of the present invention;

[0032] Fig. 13B is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig.13A The pattern mask in the embodiment uses partially overlapping exposure fields to produce the first layer features of the field-sensitive overlay target;

[0033] Fig. 13Cis a top view of a pattern mask suitable for forming second layer features according to one or more embodiments of the present invention;

[0034] Fig.13D is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig. 13C The pattern mask in the embodiment utilizes partially overlapping exposure fields to produce the second layer features of the field-sensitive overlay target;

[0035] Fig.13E is a top view of a portion of a sample according to one or more embodiments of the present invention, the illustration of which is based on Fig.9A The pattern mask in the embodiment uses partially overlapping exposure fields along two orthogonal directions to produce a field-sensitive superposition target; and

[0036] Fig.14 is a flow chart illustrating steps performed in a field-sensitive superposition metrology method according to one or more embodiments of the present invention. DETAILED DESCRIPTION

[0037] Reference will now be made in detail to the disclosed subject matter illustrated in the accompanying drawings. The present invention has been specifically shown and described with respect to certain embodiments and specific features thereof. The embodiments described herein should be construed as illustrative and not restrictive. It should be readily apparent to those skilled in the art that various changes and modifications may be made in form and detail without departing from the spirit and scope of the present invention.

[0038] Embodiments of the present invention are directed to systems and methods for providing overlay metrology and field-to-field metrology (e.g., field-sensitive overlay metrology) for a common metrology target. Field-sensitive overlay metrology can utilize new overlay measurement techniques or conventional overlay measurement techniques for field-sensitive overlay targets to provide data indicative of overlay error and / or field-to-field error. For example, the relative positions of features on a field-sensitive overlay metrology target can be sensitive not only to variations between overlapping exposures in a common exposure field (as is the case with a typical overlay target), but also to variations between adjacent exposure fields to provide data indicative of field-to-field variations.

[0039] For purposes of the present invention, the term "additive metrology" refers broadly to measuring the misalignment of features formed by two or more exposures on a common portion of a sample. In this regard, additive metrology can provide measurements of the alignment of features formed on two or more layers on a sample as well as measurements of the alignment of features formed on a common sample layer by successive exposures (e.g., double patterning, triple patterning, etc.). Additionally, for purposes of the present invention, the term "field-to-field metrology" refers broadly to measuring the difference between features formed in two or more exposures in different fields (e.g., adjacent fields) on a sample. For example, field-to-field errors can include, but are not limited to, errors in registration or scaling between fields. Thus, the systems and methods disclosed herein can provide metrological measurements of a wide variety of process errors in a common measurement step.

[0040] Certain embodiments of the present invention are directed to field-sensitive overlay targets adapted to provide data indicative of both overlay error and field-to-field error. It should be recognized herein that a typical overlay metrology target is formed by forming different portions of the target by making multiple exposures of the same area of ​​a sample, either on the same layer or different layers (e.g., the same exposure field of a lithography tool). In this regard, the relative positions and / or sizes of features formed in different exposures are indicative of alignment errors of the lithography tool aiming at the repeatedly exposed exposure fields. In contrast, a field-sensitive overlay target may be formed by making multiple exposures of a common portion of a sample, wherein at least one exposure field only partially overlaps one or more other exposure fields used to produce the target. For example, one or more features of a metrology target may be formed by exposing a first field on the sample, and one or more features may be formed by exposing a second field on the sample, wherein the second field only partially overlaps the first field at the location of the metrology target. In this regard, the relative positions and / or sizes of features in a field-sensitive overlay target are sensitive to, among other things, field-to-field variations of the various exposure fields used to produce the target.

[0041] It is contemplated herein that a field-sensitive overlay target may generally have the same design as any non-field-sensitive overlay target. For example, overlay metrology target designs suitable for adaptation include image-based metrology targets, such as, but not limited to, advanced imaging metrology (AIM) targets, AIM-in-die (AIMid) targets, frame-in-frame targets, or multi-layer AIMid (MLAIMid) targets. As another example, overlay metrology target designs suitable for adaptation include scatterometry-based overlay (SCOL) targets. Thus, the field-sensitive overlay target may be measured and characterized by any new or existing overlay metrology tool. However, the metrology algorithms used to extract information about error sources associated with the measurement of the field-sensitive overlay target may differ to account for different sources of error measured by the field-sensitive overlay target.

[0042] Additional embodiments of the present invention are directed to photomasks suitable for making field-sensitive overlay targets. For example, a photomask may include a device region that includes a pattern associated with a device feature and one or more target regions that surround the device region. Specifically, target regions on opposite sides of the device region may include complementary portions of the field-sensitive overlay target. In this regard, a full layer of the field-sensitive overlay target may be made by making overlapping exposures (e.g., overlapping exposure fields) of a sample, where the amount of overlap is designed to produce a complete pattern of the field-sensitive overlay target.

[0043] Additional embodiments of the present invention are directed to generating correction terms for a lithography tool based on both overlay data and field-to-field data generated using a field-sensitive overlay target. For example, a feed-forward correction term may be provided to the lithography tool during exposure of a subsequent layer to compensate for measurement variations on the current layer. As another example, a feedback correction term may be provided to the lithography tool to mitigate variations (e.g., drift) over time.

[0044] It is further contemplated herein that field-sensitive overlay metrology may be suitable for measuring, controlling and / or mitigating various sources of fabrication errors, including but not limited to shape variations of the photomask and / or sample, stress on the photomask and / or sample, surface tension effects on the photomask and / or sample, or errors associated with the lithography tool itself. Thus, correction terms based on field-sensitive overlay measurements may provide highly accurate and efficient control of the lithography process.

[0045] Reference now Figures 1A to 14 , a system and method for field-sensitive superposition metrology are described in more detail according to one or more embodiments of the present invention.

[0046] Figure 1Ais a conceptual diagram illustrating a fabrication system 100 according to one or more embodiments of the present invention. In one embodiment, the system 100 includes a lithography subsystem 102 that lithographically images one or more pattern elements (e.g., device pattern elements, metrology target pattern elements, etc.) on a pattern mask on a sample. The lithography subsystem 102 may include any lithography tool known in the art, such as, but not limited to, a scanner or a stepper. In another embodiment, the system 100 includes a metrology subsystem 104 to characterize one or more features on a sample. The metrology subsystem 104 may include an overlay metrology tool suitable for measuring relative positions of sample features (e.g., features of a field-sensitive overlay target). In one embodiment, the metrology subsystem 104 includes an image-based metrology tool that measures metrology data based on one or more images of the sample generated. In another embodiment, the metrology subsystem 104 includes a scatterometry-based metrology system that measures metrology data based on scattering (reflection, diffraction, diffuse scattering, etc.) of light from the sample. In another embodiment, the system 100 includes a controller 106. In another embodiment, the controller 106 includes one or more processors 108 configured to execute program instructions maintained on the memory medium 110. In this regard, the one or more processors 108 of the controller 106 may perform any of the various process steps described throughout this disclosure.

[0047] The one or more processors 108 of the controller 106 may include any processing element known in the art. In this sense, the one or more processors 108 may include any microprocessor type device configured to execute algorithms and / or instructions. In one embodiment, the one or more processors 108 may be composed of the following: a desktop computer, a large computer system, a workstation, an image computer, a parallel processor, or any other computer system (e.g., a network connection computer) configured to execute a program, which is configured to operate the system 100, as described throughout the present invention. It should be further recognized that the term "processor" can be broadly defined as any device that includes one or more processing elements that execute program instructions from a non-temporary memory medium 110. In addition, the steps described throughout the present invention can be implemented by a single controller 106 or another option is to implement multiple controllers. In addition, the controller 106 may include one or more controllers housed in a common housing or multiple housings. In this way, any controller or controller combination in the controller can be individually packaged as a module suitable for integration into the system 100. Furthermore, the controller 106 may analyze the data received from the detector 132 and feed the data to additional components within the system 100 or external to the system 100 (eg, the lithography subsystem 102 ).

[0048] The memory medium 110 may include any storage medium known in the art that is suitable for storing program instructions that can be executed by the associated one or more processors 108. For example, the memory medium 110 may include a non-transitory memory medium. As another example, the memory medium 110 may include, but is not limited to, a read-only memory, a random access memory, a magnetic or optical storage device (e.g., a disk), a tape, a solid-state drive, etc. It should be further noted that the memory 110 and the one or more processors 108 can be housed in a common controller housing. In one embodiment, the memory 110 can be remotely located relative to the physical location of the one or more processors 108 and the controller 106. For example, the one or more processors 108 of the controller 106 can access a remote memory (e.g., a server) that can be accessed via a network (e.g., the Internet, an intranet, etc.). Therefore, the above description should not be construed as limiting the present invention, but is merely illustrative.

[0049] Figure 1B is a conceptual diagram illustrating a lithography subsystem 102 in accordance with one or more embodiments of the present invention. In one embodiment, the lithography subsystem 102 includes a lithography illumination source 112 configured to generate an illumination beam 114. The one or more illumination beams 114 may include one or more selected wavelengths of light including, but not limited to, ultraviolet (UV) radiation, visible radiation, or infrared (IR) radiation.

[0050] The illumination of the lithographic illumination source 112 may have any spatial distribution (e.g., an illumination pattern). For example, the lithographic illumination source 112 may include, but is not limited to, a monopole illumination source, a dipole illumination source, a C-Quad illumination source, a quasar illumination source, or a free-form illumination source. In this regard, the lithographic illumination source 112 may generate a coaxial illumination beam 114 in which the illumination propagates along (or parallel to) the optical axis 116 and / or any number of off-axis illumination beams 114 in which the illumination propagates at an angle relative to the optical axis 116.

[0051] It should be further noted herein that for purposes of the present invention, an illumination pole of a lithographic illumination source 112 may represent illumination from a specific location. In this regard, each spatial location (e.g., with respect to optical axis 116) of a lithographic illumination source 112 may be considered an illumination pole. Furthermore, an illumination pole may have any shape or size known in the art. Additionally, a lithographic illumination source 112 may be considered to have an illumination distribution corresponding to the distribution of illumination poles.

[0052] Furthermore, the lithographic illumination source 112 can generate the illumination beam 114 by any method known in the art. For example, the illumination beam 114 can be formed in the form of illumination from an illumination pole of the lithographic illumination source 112 (e.g., a portion of the illumination distribution of the lithographic illumination source 112, etc.). As another example, the lithographic illumination source 112 can include multiple illumination sources for generating multiple illumination beams 114.

[0053] In another embodiment, the lithography subsystem 102 includes a mask support 118. The mask support 118 is configured to hold a pattern mask 120. In another embodiment, the lithography subsystem 102 includes a set of projection optics 122 configured to project an image of the pattern mask 120 illuminated by the one or more illumination beams 114 onto a sample 124 disposed on a sample stage 126 to produce a printed pattern element corresponding to the image of the pattern mask 120. In another embodiment, the mask support 118 can be configured to actuate or position the pattern mask 120. For example, the mask support 118 can actuate the pattern mask 120 to a selected position relative to the projection optics 122 of the system 100.

[0054] The sample 124 may include any number of photosensitive materials and / or material layers suitable for receiving an image of the pattern mask 120. For example, the sample 124 may include a photoresist layer 128. In this regard, the set of projection optics 122 may project an image of the pattern mask 120 onto the photoresist layer 128 to expose the photoresist layer 128 and a subsequent etching step may remove the exposed material (e.g., positive etching) or the unexposed material (e.g., negative etching) to provide printed features on the sample 124. In addition, the pattern mask 120 may be used in any imaging configuration known in the art. For example, the pattern mask 120 may be a positive mask (e.g., a bright field mask) that positively images a pattern element into a printed pattern element. As another example, the pattern mask 120 may be a negative mask (e.g., a dark field mask) in which the pattern elements of the pattern mask 120 form negative printed pattern elements (e.g., gaps, spaces, etc.).

[0055] The controller 106 may be communicatively coupled to any element or combination of elements in the lithography subsystem 102 , such as, but not limited to, a mask support device 118 and / or a sample stage 126 for guiding the transfer of pattern elements on the pattern mask 120 to the sample 124 , and a lithography illumination source 112 for controlling one or more characteristics of the illumination beam 114 .

[0056] Figure 1C1 is a block diagram of a metrology subsystem 104 according to one or more embodiments of the present invention. The system 100 may generate one or more images associated with light emitted from the sample 124 onto at least one detector 132 (e.g., sample light 130) using any method known in the art. In one embodiment, the detector 132 is located at a field plane to generate an image of one or more features on the sample 124. In this regard, the system 100 may be used as an image-based overlay metrology tool. In another embodiment, the detector 132 is located at a pupil plane to generate an image based on the angle of light emitted from the sample 124 (e.g., based on reflection, diffraction, scattering, etc.). In this regard, the system 100 may be used as a scatterometry-based metrology tool.

[0057] In one embodiment, the metrology subsystem 104 includes a metrology radiation source 134 to generate a metrology radiation beam 136. The metrology radiation source 134 may be the same as the photolithography radiation source 112 or may be a separate radiation source configured to generate a separate metrology radiation beam 136. The metrology radiation beam 136 may include one or more selected wavelengths of light including, but not limited to, vacuum ultraviolet (VUV) radiation, deep ultraviolet (DUV) radiation, ultraviolet (UV) radiation, visible radiation, or infrared (IR) radiation. The metrology radiation source 134 may further generate a metrology radiation beam 136 including any range of selected wavelengths. In another embodiment, the metrology radiation source 134 may include a spectrally tunable radiation source to generate a metrology radiation beam 136 having a tunable spectrum.

[0058] The metrological radiation source 134 may further generate a metrological radiation beam 136 having any temporal distribution. For example, the metrological radiation source 134 may generate a continuous metrological radiation beam 136, a pulsed metrological radiation beam 136, or a modulated metrological radiation beam 136. Additionally, the metrological radiation beam 136 may be delivered from the metrological radiation source 134 via free space propagation or via guided light (e.g., optical fiber, light duct, etc.).

[0059] In another embodiment, the metrology illumination source 134 directs a metrology illumination beam 136 to the sample 124 via an illumination path 138. The illumination path 138 may include one or more lenses 140 or additional illumination optical components 142 suitable for modifying and / or adjusting the metrology illumination beam 136. For example, the one or more illumination optical components 142 may include, but are not limited to, one or more polarizers, one or more filters, one or more beam splitters, one or more diffusers, one or more homogenizers, one or more apodizers, one or more beam shapers, or one or more shutters (e.g., mechanical shutters, electro-optical shutters, acousto-optical shutters, etc.). As another example, the one or more illumination optical components 142 may include an aperture stop to control the angle of illumination onto the sample 124 and / or a field stop to control the spatial span of illumination onto the sample 124. In one example, the illumination path 138 includes an aperture stop located at a plane conjugate to the back focal plane of the objective 144 to provide telecentric illumination for the sample. In another embodiment, the system 100 includes an objective 144 that focuses the metrology illumination beam 136 onto the sample 124.

[0060] In another embodiment, the sample 124 is disposed on a sample stage 146. The sample stage 146 may include any device suitable for positioning the sample 124 within the system 100. For example, the sample stage 146 may include any combination of a linear translation stage, a rotation stage, a tilt-up stage, and the like.

[0061] In another embodiment, the detector 132 is configured to capture radiation (eg, sample light 130) emitted from the sample 124 via a focusing path 148. For example, the focusing path 148 may include, but need not include, a focusing lens (eg, Figure 1C ) or one or more additional focusing path lenses 150. In this regard, the detector 132 may receive radiation reflected or scattered from the sample 124 (e.g., via specular reflection, diffuse reflection, etc.) or generated by the sample 124 (e.g., associated with absorption of the metrological radiation beam 136). Fluorescence wait).

[0062] The focusing path 148 may further include any number of focusing optical components 152 to direct and / or modify the illumination focused by the objective 144, including but not limited to one or more focusing path lenses 150, one or more filters, one or more polarizers, or one or more beam stops. Additionally, the focusing path 148 may include: a field stop to control the spatial span of the sample that is imaged onto the detector 132; or an aperture stop to control the angular span of the illumination from the sample used to produce the image on the detector 132. In another embodiment, the focusing path 148 includes an aperture stop located in a plane conjugate to the back focal plane of the optical element objective 144 to provide telecentric imaging for the sample.

[0063] Detector 132 may include any type of optical detector known in the art suitable for measuring the illumination received from sample 124. For example, detector 132 may include a sensor suitable for producing one or more images of static sample 124 (e.g., in a static mode of operation), such as, but not limited to, a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) sensor, a photomultiplier tube (PMT) array, or an avalanche photodiode (APD) array. As another example, detector 132 may include a sensor suitable for producing one or more images of sample 124 in motion (e.g., a scanning mode of operation), such as, but not limited to, a line sensor or a time delay and integration (TDI) sensor.

[0064] In another embodiment, the detector 132 may include a spectral detector suitable for identifying wavelengths of radiation emitted from the sample 124. In another embodiment, the system 100 may include multiple detectors 132 (e.g., associated with multiple beam lines generated by one or more beam splitters) to facilitate multiple metrology measurements made by the system 100.

[0065] In one embodiment, Figure 1C , system 100 includes a beam splitter 154 oriented so that objective 144 can simultaneously direct metrology illumination beam 136 to sample 124 and collect radiation emitted from sample 124. In this regard, system 100 can be configured to be in epi-illumination mode.

[0066] In another embodiment, the controller 106 is communicatively coupled to one or more elements of the system 100. In this regard, the controller 106 may transmit and / or receive data from any component of the system 100. For example, the controller 106 may be configured to receive data, including but not limited to one or more images from the detector 132.

[0067] Figure 2 1 is a conceptual top view of a sample 124 illustrating a plurality of overlapping exposure fields 202 associated with a plurality of lithography steps performed by the lithography subsystem 102 associated with fabrication of a particular sample layer in accordance with one or more embodiments of the present invention. In one embodiment, a pattern mask 120 is imaged onto each exposure field 202. Furthermore, the same pattern mask 120 may be repeatedly imaged onto each exposure field 202 or multiple pattern masks 120 may be imaged onto a selected exposure field 202. However, it should be understood that Figure 2 Not drawn to scale. Rather, Figure 2Parameters in , such as, but not limited to, the size of each exposure field 202 relative to the size of sample 124, the number of exposure fields 202, or the amount of overlap between adjacent exposure fields 202, are selected for illustrative purposes and should not be construed as limiting.

[0068] In one embodiment, Figure 2 , adjacent exposure fields 202 may overlap to form overlap regions 204 distributed across sample 124. Device features (e.g., associated with dies distributed across sample 124) may be fabricated in any of non-overlap regions 206, while field-sensitive overlay targets on a particular sample layer, or portions thereof, may be formed in any of overlap regions 204 based on exposures from adjacent overlapping exposure fields 202. In contrast, it should be recognized herein that typical overlay metrology targets may be formed on the same layer or on different layers using fully overlapping exposure fields 202 associated with different lithography steps.

[0069] In another embodiment, the pattern of exposure field 202 may be replicated in multiple lithography steps associated with the fabrication process. For example, a series of material deposition steps, lithography steps using the pattern of exposure field 202 (e.g., Figure 2 ), etching steps, etc. A first set of pattern elements associated with a first sample layer may be made using a series of additional material deposition steps, photolithography steps using the pattern of exposure field 202, etching steps, etc., wherein the patterns of exposure field 202 associated with the first sample layer and the second sample layer are aligned. A similar process may be implemented on a single sample layer to perform multiple aligned exposures (e.g., a double patterning process, etc.).

[0070] Reference now Figures 3 to 13E , field-sensitive metrology targets and their formation are described in greater detail according to one or more embodiments of the present invention. It is contemplated herein that field-sensitive metrology targets may include features formed by any number of overlapping exposure fields 202 on any number of sample layers. Figures 3 to 9B Illustrated are non-limiting examples of dual-layer field-sensitive overlay targets in which features associated with a first sample layer are formed using one exposure field 202, and features associated with a second layer are formed using adjacent overlapping exposure fields 202. In these designs, the relative position and / or size of first layer features with respect to second layer features is sensitive to, among other things, field-to-field variations between lithography steps associated with different sample layers. Figures 10 to 11B A non-limiting example of a single-layer field-sensitive overlay target is illustrated. In this design, the relative position and / or size of first layer features relative to second layer features is sensitive to, among other things, field-to-field variations between lithography steps associated with a single sample layer. Figures 12 to 13EIllustrated is a non-limiting example of a two-layer field-sensitive overlay target formed using four exposures across two exposure fields 202: the first layer features use adjacent exposure fields 202 to Figures 10 to 11B , and the second layer features are made in a similar manner to the illustration in , and the second layer features are made using the same adjacent exposure field 202 used for the first layer features. In this design, the portion of the target that includes features formed by completely overlapping exposure fields 202 located on different layers can be used as a traditional overlay target and provide data indicative of alignment errors and / or scaling errors of the lithography tool used for consecutive exposures of the respective exposure fields 202. In addition, the portion of the target that includes features formed by partially overlapping exposure fields 202 can provide data indicative of field-to-field errors. In addition, it should be understood that the examples herein are provided for illustrative purposes only and should not be construed as limiting. For example, additional designs of single-layer or dual-layer field-sensitive overlay targets that provide traditional overlay data and / or field-to-field data are within the spirit and scope of the present invention. As another example, the field-sensitive overlay target may include features on three or more sample layers formed by at least one exposure field 202 that only partially overlaps other exposure fields 202 at the target location.

[0071] Figure 3 2 is a conceptual top view of a dual-layer field-sensitive overlay target 300 according to one or more embodiments of the present invention. In one embodiment, the field-sensitive overlay target 300 includes a first layer of target features 302 formed using a first exposure field 202 and a second layer of target features 304 formed using a second exposure field, wherein the second exposure field 202 only partially overlaps the first exposure field 202. For example, using Figure 2 As shown in FIG. 3 , first layer target features 302 may be associated with exposure field 202 a and second layer target features 304 may be associated with exposure field 202 b. Thus, first layer target features 302 and second layer target features 304 are complementary parts of full field sensitive superposition target 300.

[0072] It should be understood that Figure 3 The layout of the field-sensitive overlay target 300 in FIG. 1 is intended to be illustrative and not limiting. The first layer target features 302 and the second layer target features 304 may be arranged in any configuration suitable for overlay measurement. For example, the layout of the first layer target features 302 and the second layer target features 304 is not limited to Figure 3 304. In the embodiment of the present invention, the first layer target features 302 and the second layer target features 304 each include two grid areas and are distributed along a cross diagonal line. Instead, the first layer target features 302 and the second layer target features 304 can be distributed in any number of grid areas in any pattern suitable for superposition measurement. In one example, the first layer target features 302 and the second layer target features 304 can overlap completely or partially. In addition, either the first layer target features 302 or the second layer target features 304 can be segmented along one or more directions.

[0073] Thus, it is further contemplated herein that any technique may be used to determine the relative positions of features formed by different exposures, the positions of which may be affected by various sources of error, including overlay error and field-to-field error as previously described herein. For example, the position of first layer target feature 302 may be directly compared to second layer target feature 304. As another example, the centers of symmetry (e.g., rotational symmetry, reflection symmetry, etc.) associated with first layer target feature 302 and second layer target feature 304 may be compared.

[0074] Figures 4A to 9B Graphical instructions Figure 3 2 and 3. Various designs of field-sensitive superposition targets 300 are illustrated in FIG. 1 and illustrate associated pattern masks 120 suitable for making various designs using adjacent partially overlapping exposure fields 202. However, it should be understood that the present invention is provided for illustration purposes only. Figures 4A to 9B The design of the field-sensitive overlay target 300 illustrated in FIG. 2 should not be construed as limiting. It is contemplated herein that any overlay target design may be adapted to be field-sensitive by using adjacent partially overlapping exposure fields 202 to make complementary portions.

[0075] Figure 4A is suitable for forming according to one or more embodiments of the present invention Figure 3 The pattern mask 402 (eg, corresponding to Figure 1B 4. In one embodiment, pattern mask 402 includes a device region 404 including a pattern of device features (not shown) associated with a semiconductor device being fabricated. In another embodiment, pattern mask 402 includes a complementary portion of field-sensitive overlay target 300 located on an opposite side of device region 404 but within boundary 406 of the imaging region. For example, pattern mask 402 includes a complementary portion of field-sensitive overlay target 300 along a horizontal axis for forming a full field-sensitive overlay target 300 using exposure fields 202 adjacent along a horizontal direction, and also includes a complementary portion of field-sensitive overlay target 300 along a vertical axis for forming a full field-sensitive overlay target 300 using exposure fields 202 adjacent along a vertical direction. Specifically, pattern elements 408 associated with first layer target features 302 are located on the left and top side of device region 404, and pattern elements 410 associated with second layer target features 304 are located on the right and bottom side of device region 404.

[0076] Figure 4B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Figure 4AThe pattern mask 402 is used to make the field-sensitive overlay target 300 along two orthogonal directions using overlapping exposure fields 202. In one embodiment, each exposure field 202 includes an image of the pattern mask 402. In addition, the overlap interval and overlap amount between adjacent exposure fields 202 can be selected so that complementary portions of the field-sensitive overlay target 300 overlap on the sample 124 to form the full field-sensitive overlay target 300 in the overlap region 204, while device features associated with the device regions 404 of the pattern mask 402 are formed in the non-overlap region 206.

[0077] For example, field-sensitive overlay target 300a is formed using first layer target features 302 from first exposure field 202 (e.g., exposure field 202a) and second layer target features 304 from second exposure field 202 (e.g., exposure field 202b). As another example, field-sensitive overlay target 300b is formed using first layer target features 302 from first exposure field 202 (e.g., exposure field 202a) and second layer target features 304 from third exposure field 202 (e.g., exposure field 202c).

[0078] Reference now Figures 5A to 9B , various designs of field-sensitive overlay targets and associated pattern masks are described in more detail according to one or more embodiments of the present invention. Figure 4A and 4B The description associated with the pattern mask 402 on the sample 124 of the associated field-sensitive superposition target 300 and the partially overlapping exposure of the pattern mask 402 may be applied to Figures 5A to 9B The target design illustrated in .

[0079] Figure 5A is suitable for forming according to one or more embodiments of the present invention Figure 3 The pattern mask 502 of the design of the field-sensitive superposition target 300 including four grid areas illustrated in FIG. Figure 1B 1 , wherein portions of first layer target features 302 and portions of second layer target features 304 are located in each grid region. Specifically, pattern elements 408 associated with first layer target features 302 are located on the left side and bottom side of device area 404, and pattern elements 410 associated with second layer target features 304 are located on the right side and top side of device area 404. Figure 5B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Figure 5AThe pattern mask 502 in the embodiment of the present invention is used to make a field-sensitive superposition target 300 using partially overlapping exposure fields 202 along two orthogonal directions. In this design, the relative positions of the first layer target features 302 and the second layer target features 304 can be determined by comparing the respective centers of rotational symmetry, but need not be determined. For example, the first layer target features 302 and the second layer target features 304 exhibit 90 degree rotational symmetry. However, it is contemplated herein that designs including other types of symmetry (including but not limited to 180 degree rotational symmetry or reflection symmetry) are within the spirit and scope of the present invention.

[0080] Fig. 6A is suitable for forming according to one or more embodiments of the present invention Figure 3 The pattern mask 602 (eg, corresponding to the frame design of the field-sensitive overlay target 300 illustrated in FIG. 3 ) is shown in FIG. Figure 1B 1 , a top view of a pattern mask 120 in FIG. 1 , in which portions of a first layer target feature 302 and portions of a second layer target feature 304 in a frame-in-frame design are located in a series of nested frames. Figure 6B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig. 6A The pattern mask 602 in FIG. 1 is used to produce the field-sensitive superposition target 300 using partially overlapping exposure fields 202. Although not shown, Figure 4B and 5B A similar approach as illustrated in Figure 6B The field-sensitive superposition target 300 is formed by partially overlapping exposure of the pattern mask 602 in the vertical direction.

[0081] Fig. 7A is suitable for forming according to one or more embodiments of the present invention Figure 3 The pattern mask 702 of the “ruler” type design of the field-sensitive superposition target 300 illustrated in FIG. Figure 1B FIG. 1 is a top view of a pattern mask 120 in FIG. 1 , in which a portion of a first layer target feature 302 and a portion of a second layer target feature 304 are located in a series of nested comb patterns in the “ruler” type design. Figure 7B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig. 7A The pattern mask 702 in FIG. 1 is used to produce the field-sensitive superposition target 300 using partially overlapping exposure fields 202. Although not shown, Figure 4B and 5B A similar approach as illustrated in Figure 7B The field-sensitive superposition target 300 is formed by partially overlapping exposure of the pattern mask 702 in the vertical direction.

[0082] Fig. 8A is suitable for forming according to one or more embodiments of the present invention Figure 3 The pattern mask 802 (eg, corresponding to Figure 1B FIG. 1 is a top view of a pattern mask 120 , in which the first layer target features 302 are interlaced with the second layer target features 304 in the AIMid design. Figure 8B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig. 8A The pattern mask 802 in FIG. 1 is used to produce the field-sensitive superposition target 300 using partially overlapping exposure fields 202. Although not shown, Figure 4B and 5B A similar approach as illustrated in Figure 8B The field-sensitive superposition target 300 is formed by partially overlapping exposure of the pattern mask 802 in the vertical direction.

[0083] Fig.9A One or more embodiments of the present invention are suitable for forming Figure 3 The pattern mask 902 (eg, corresponding to Figure 1B FIG. 1 is a top view of a pattern mask 120 in an AIMid design in which first layer target features 302 overlap with second layer target features 304 to form a cross pattern. Fig. 9B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig.9A The pattern mask 902 in FIG. 1 is used to produce the field-sensitive superposition target 300 using partially overlapping exposure fields 202. Although not shown, it can be combined with Figure 4B and 5B In a similar manner as illustrated in the diagram, Fig. 9B The field-sensitive superposition target 300 is formed by partially overlapping exposure of the pattern mask 902 in the vertical direction.

[0084] Reference now Fig.10 and 11B , a single-layer field-sensitive overlay target 1000 is described according to one or more embodiments of the present invention. Fig.10 is a conceptual top view of a single-layer field-sensitive overlay target 1000 according to one or more embodiments of the present invention. Fig.10 The double-layer field-sensitive superposition target 1200 is similar to Figure 3, but all features are formed using exposure fields 202 associated with a common sample layer. Specifically, single-layer field-sensitive overlay target 1000 may include a first set of target features 1002 associated with a first exposure field 202 (e.g., exposure field 202a) and a second set of target features 1004 associated with a second exposure field 202 (e.g., exposure field 202b or exposure field 202c).

[0085] Fig.11A is suitable for forming according to one or more embodiments of the present invention Fig.10 The pattern mask 1102 of the field-sensitive superposition target 1000 illustrated in FIG. Figure 1B Specifically, pattern element 1104 is associated with first set of target features 1002, and pattern element 1106 is associated with second set of target features 1004. Fig. 11B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig.11A The pattern mask 1102 in the embodiment of the present invention is used to produce a field-sensitive overlay target 1000 using partially overlapping exposure fields 202 along two orthogonal directions.

[0086] Reference now Figures 12 to 13E , a dual-layer field-sensitive overlay target 1200 is described according to one or more embodiments of the present invention. Fig.12 is a conceptual top view of a single-layer field-sensitive overlay target 1000 according to one or more embodiments of the present invention.

[0087] In one embodiment, the field-sensitive overlay target 1200 is formed by four exposures. For example, the field-sensitive overlay target 1200 may include a first set of first layer features 1202 formed by a first exposure field 202 (e.g., exposure field 202a) and a second set of first layer features 1204 formed by a second exposure field 202 (e.g., exposure field 202b or exposure field 202c) partially overlapping the first exposure field 202. The field-sensitive overlay target 1200 may further include a first set of second layer features 1206 formed by the first exposure field 202 (e.g., exposure field 202a) on the second sample layer and a second set of second layer features 1208 formed by the second exposure field 202 (e.g., exposure field 202b or exposure field 202c).

[0088] Fig.13A is a pattern mask 1302 (eg, corresponding to a first layer of features) suitable for forming first layer features (eg, a first set of first layer features 1202 and a second set of first layer features 1204) according to one or more embodiments of the present invention. Figure 1BSpecifically, pattern element 1304 is associated with the first set of first layer features 1202, and pattern element 1306 is associated with the second set of first layer features 1204.

[0089] Fig. 13B is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig.13A The pattern mask 1302 in 1304 is used to make the first layer features of the field-sensitive overlay target 1200 using partially overlapping exposure fields 202 (eg, exposure fields 202a, 202b in the lithography step for the first layer).

[0090] Fig. 13C is a pattern mask 1308 (eg, corresponding to a plurality of second layer features) suitable for forming second layer features (eg, first set of second layer features 1206 and second set of second layer features 1208) according to one or more embodiments of the present invention. Figure 1B Specifically, pattern element 1310 is associated with first set of second layer features 1206, and pattern element 1312 is associated with second set of second layer features 1208.

[0091] Fig.13D is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig. 13C The pattern mask 1308 in the embodiment of the present invention utilizes partially overlapping exposure fields 202 (e.g., exposure fields 202a, 202b in the photolithography step for the second layer) to produce second layer features of the field-sensitive overlay target 1200. In addition, the exposure fields 202a, 202b in the photolithography step for the second layer may completely overlap with the corresponding exposure fields 202a, 202b in the photolithography step for the first layer.

[0092] Fig.13E is a top view of a portion of a sample 124 according to one or more embodiments of the present invention, the illustration of which is based on Fig.13A and 13C The pattern masks 1302 and 1308 in FIG. 1 are used to produce the field-sensitive overlay target 1200 using partially overlapping exposure fields 202 along two orthogonal directions.

[0093] like Figures 12 to 13EAs illustrated, the field-sensitive overlay target 1200 can provide typical overlay data and field-to-field data associated with each layer and between layers. For example, since the first set of first layer features 1202 and the first set of second layer features 1206 are formed by completely overlapping exposure fields 202 (e.g., exposure fields 202a) in the first and second layers, the relative positions and / or sizes of the first set of first layer features 1202 relative to the first set of second layer features 1206 can indicate typical overlay errors caused by typical overlay targets associated with alignment lithography steps across multiple layers. In addition, the second set of first layer features 1204 and the second set of second layer features 1208 can provide similar data.

[0094] However, the field-sensitive overlay target 1200 may also provide data indicative of various field-to-field errors. For example, Fig.13A The pattern mask 1302 and Fig. 13C The pattern mask 1308 is similarly used as Fig.11A . Thus, the relative position and / or size of the first set of first layer features 1202 relative to the second set of first layer features 1204 may indicate field-to-field errors in the first layer, while the relative position and / or size of the first set of second layer features 1206 relative to the second set of second layer features 1208 may indicate field-to-field errors in the second layer. Additionally, the field-sensitive overlay target 1200 may provide data indicative of field-to-field errors across multiple layers. For example, the relative position and / or size of the first set of first layer features 1202 relative to the second set of second layer features 1208 may indicate field-to-field errors across multiple layers, similar to Figures 3 to 13E Similar data may also be obtained based on the second set of first layer features 1204 and the second set of second layer features 1208.

[0095] As previously described herein, it should be understood that Figures 3 to 13E is provided for illustration purposes only and should not be construed as limiting. Rather, a field-sensitive overlay target may include any number of features formed by any number of exposures, wherein at least some of the features of the target are formed by exposure fields 202 that only partially overlap other exposure fields 202 used to form the target. Furthermore, a field-sensitive overlay target may include a combination of features illustrated herein. For example, a field-sensitive overlay target may include features located on three or more sample layers.

[0096] Fig.14is a flow chart illustrating steps performed in a method 1400 for field-sensitive superposition metrology according to one or more embodiments of the present invention. Applicants note that the embodiments and enabling techniques previously described herein in the context of system 100 are interpreted as extending to method 1400. However, it is further noted that method 1400 is not limited to the architecture of system 100.

[0097] In one embodiment, the method includes step 1402: using a photolithography tool to expose a first exposure field on a sample to form at least one first feature of a metrology target (e.g., a field-sensitive overlay target). In another embodiment, the method includes step 1404: using the photolithography tool to expose a second exposure field on the sample to form at least one second feature of the metrology target, wherein the second exposure field partially overlaps the first exposure field. Specifically, the second exposure field may overlap the first exposure field at the location of the metrology target on the sample. In this regard, the first feature of the metrology target and the second feature of the metrology target may form complementary portions of the metrology target.

[0098] It is contemplated herein that the first exposure field may be on the same layer or on a different layer than the second exposure field. Thus, the first feature and the second feature may be on the same layer or on different layers of the sample. Furthermore, the method may include making additional exposures to form additional features of the metrology target, wherein each additional exposure completely or partially overlaps any other exposure used to produce the features of the metrology target.

[0099] For example, Figures 3 to 13E Various non-limiting examples of implementations of steps 1402 and 1404 using system 100 are illustrated.

[0100] In another embodiment, the method includes step 1406 of generating metrology data associated with a metrology target using a metrology tool (e.g., metrology subsystem 104, etc.). In another embodiment, the method includes step 1408 of determining one or more manufacturing errors during fabrication of the metrology target based on the metrology data. For example, the relative position and / or size of a feature (e.g., a first feature, a second feature, any additional features, etc.) of the metrology target may indicate a manufacturing error during fabrication of the metrology target, such as, but not limited to, an error associated with a lithography tool (e.g., field scaling error, field-to-field alignment error, sample-to-mask alignment error, overlay error, etc.) or an error associated with a sample (e.g., sample stress, sample imperfections, etc.).

[0101] In another embodiment, the method includes step 1410 of generating one or more correction terms based on the one or more fabrication errors to adjust one or more fabrication parameters of a lithography tool in one or more subsequent lithography steps.

[0102] Step 1410 may include any combination of feedback or feed-forward control of a lithography tool that generates correction terms for use in making metrology targets (and therefore device features on a sample). For example, feed-forward correction terms may be provided to a lithography tool during exposure of subsequent layers of the same sample to compensate for measurement variations on the current sample layer. As another example, feedback correction terms may be provided to a lithography tool to mitigate variations (e.g., drift) over time. These correction terms may be applied to different portions of the same sample, to different samples within the same batch, or to samples across multiple batches.

[0103] It is contemplated herein that a metrology target (e.g., a field-sensitive overlay target) generated by method 1400 that is sensitive to field-to-field errors may be able to generate more accurate and effective correction terms for a lithography tool than a typical overlay target. For example, the field-sensitive metrology target disclosed herein may facilitate determination of a high-resolution reference point (HRRP) to reduce overlay errors between stitched target grids originating from different exposure fields. As another example, the field-sensitive metrology target disclosed herein may be printed along field edges to facilitate intra-field and inter-field patterning warp geometry (PWG) measurements or to aid in fine-tuning or validating existing PWG techniques.

[0104] The subject matter described herein sometimes illustrates different components contained in or connected to other components. It should be understood that these depicted architectures are only exemplary, and in fact many other architectures that achieve the same functionality can be implemented. In a conceptual sense, any component arrangement that achieves the same functionality is effectively "associated" so that the desired functionality is achieved. Therefore, any two components that are combined to achieve a specific functionality herein can be considered to be "associated" with each other so that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components that are so associated can also be considered to be "connected" or "coupled" to each other to achieve the desired functionality, and any two components that can be so associated can also be considered to be "coupleable" to each other to achieve the desired functionality. Specific examples that can be coupled include, but are not limited to, components that can physically interact and / or physically interact and / or components that can wirelessly interact and / or wirelessly interact and / or components that can logically interact and / or logically interact.

[0105] It is believed that the invention and its many attendant advantages will be appreciated from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of components without departing from the disclosed subject matter or sacrificing all of its substantial advantages. The forms described are merely illustrative, and the appended claims are intended to encompass and include such changes. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. A metering system, comprising: A controller communicatively coupled to the metrology tool, the controller comprising one or more processors configured to execute program instructions that cause the one or more processors to: receiving a metrology target design, wherein the metrology target design includes at least one first feature formed by exposing a first exposure field on a first layer of a sample using a photolithography tool, wherein the metrology target design further includes at least one second feature formed by exposing a second exposure field on a second layer of the sample different from the first layer using the photolithography tool, wherein the second exposure field partially overlaps the first exposure field, wherein the second exposure field overlaps the first exposure field at a location of a metrology target on the sample; receiving metrology data associated with the metrology target designed and manufactured according to the metrology target; determining one or more manufacturing errors during manufacturing of the metrology target based on the metrology data; and One or more correction terms are generated based on the one or more fabrication errors to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps.

2. The metrology system of claim 1, wherein the one or more fabrication errors comprise errors associated with the photolithography tool.

3. The metrology system of claim 2, wherein the one or more fabrication errors include at least one of a field scaling error, a field-to-field alignment error, a sample-to-mask alignment error, or an overlay error.

4. The metrology system of claim 1, wherein the one or more manufacturing errors include an error associated with the sample.

5. The metrology system of claim 4, wherein the one or more manufacturing errors include at least one of field sample stress or sample imperfections.

6. The metrology system of claim 1, wherein the metrology tool comprises: Image-based metrology tools.

7. The metrology system according to claim 6, wherein the metrology target design comprises: Design of at least one of an Advanced Imaging Metrology (AIM) target, an AIM-in-die target, a multi-layer AIM-in-die target, a frame-in-frame target, or a "ruler" target.

8. The metrology system of claim 1, wherein the metrology tool comprises: Scatterometry-based metrology tools.

9. The metering system according to claim 8, wherein the metering target comprises: Scatterometry metrology targets.

10. The metrology system of claim 1, wherein the metrology target is rotationally symmetric about at least one of 90 degrees or 180 degrees.

11. The metrology system of claim 1, wherein the metrology target is reflection symmetric about at least one axis.

12. The metrology system of claim 1 , wherein the metrology target design further comprises at least a third feature formed by exposing a third exposure field on the first layer of the sample using the photolithography tool, wherein the third exposure field partially overlaps with the first exposure field on the first layer of the sample and completely overlaps with the second exposure field on the second layer of the sample, wherein the metrology target design further comprises at least a fourth feature formed by exposing a fourth exposure field on the second layer of the sample using the photolithography tool, wherein the fourth exposure field partially overlaps with the first exposure field on the first layer of the sample and completely overlaps with the second exposure field on the second layer of the sample.

13. The metrology system of claim 12, wherein the one or more manufacturing errors include a stacking error based on at least one of a position of the first feature relative to the third feature or a position of the second feature relative to the fourth feature, wherein the one or more manufacturing errors further include a field-to-field error based on at least one of a position of the first feature relative to the fourth feature or a position of the second feature relative to the third feature.

14. A pattern mask comprising: one or more device pattern elements located in a device region of the pattern mask; a first set of metrology pattern elements located in a first target area; as well as a second group of metrology pattern elements located in a second target area, wherein the first target area and the second target area are arranged on opposite sides of the device area along a first direction, wherein the first group of metrology pattern elements and the second group of metrology pattern elements are configured to form at least a portion of a metrology target on the sample when the pattern mask is exposed on the sample using a first exposure field and a second exposure field, the first exposure field and the second exposure field being distributed so that the first target area of ​​the first exposure field overlaps with the second target area of ​​the second exposure field at a position of the metrology target on the sample.

15. The pattern mask of claim 14, wherein metrology measurements of the metrology target indicate one or more manufacturing errors along the first direction.

16. The pattern mask of claim 15, wherein the one or more fabrication errors include errors associated with a lithography tool used to expose the metrology target on the sample.

17. The pattern mask of claim 16, wherein the one or more fabrication errors include at least one of a field scaling error, a field-to-field alignment error, a sample-to-mask alignment error, or an overlay error.

18. The pattern mask of claim 15, wherein the one or more manufacturing errors include errors associated with the sample.

19. The pattern mask of claim 18, wherein the one or more manufacturing errors include at least one of field sample stress or sample imperfections.

20. The pattern mask of claim 14, wherein the metrology target comprises: At least one of an Advanced Imaging Metrology (AIM) target, an AIM-in-die target, a multi-layer AIM-in-die target, a frame-in-frame target, a "ruler" target, or a scatterometry target.

21. The pattern mask of claim 14, wherein the metrology target is rotationally symmetric about at least one of 90 degrees or 180 degrees.

22. The pattern mask according to claim 14, further comprising: a third set of metrology pattern elements located in a third target area; and a fourth group of metrology pattern elements located in a fourth target area, wherein the third target area and the fourth target area are arranged on opposite sides of the device area along a second direction orthogonal to the first direction, wherein the third group of metrology pattern elements and the fourth group of metrology pattern elements are configured to form an additional metrology target on the sample when the pattern mask is exposed on the sample using the first exposure field and the third exposure field, the first exposure field and the third exposure field being distributed so that the third target area of ​​the first exposure field overlaps with the fourth target area of ​​the third exposure field at a position of the additional metrology target on the sample.

23. The pattern mask of claim 22, wherein metrology measurements of the metrology target indicate one or more manufacturing errors along the first direction.

24. A measurement method, comprising: Using a photolithography tool to expose a first exposure field on a first layer of the sample to form at least one first feature of a metrology target; exposing a second exposure field on a second layer of the sample different from the first layer using the photolithography tool to form at least one second feature of the metrology target, wherein the second exposure field partially overlaps with the first exposure field, and wherein the second exposure field overlaps with the first exposure field at a location of the metrology target on the sample; generating metrology data associated with the metrology target using a metrology tool; determining one or more manufacturing errors during manufacturing of the metrology target based on the metrology data; and One or more correction terms are generated based on the one or more fabrication errors to adjust one or more fabrication parameters of the lithography tool in one or more subsequent lithography steps.

25. The metrology method of claim 24, wherein the one or more fabrication errors comprise errors associated with the photolithography tool.

26. The metrology method of claim 24, wherein the one or more fabrication errors include at least one of a field scaling error, a field-to-field alignment error, a sample-to-mask alignment error, or an overlay error.

Images