Measurement system and measurement method

Abstract

This invention provides a system and method for high-throughput overlay and field-to-field measurements. [Solution] The processor 108 of the control device 106 receives a first measurement dataset related to a first set of measurement target features on the sample. The first set of measurement target features includes one or more first features formed by exposing a first exposure field on a first layer of the sample, and one or more second features formed by exposing a second exposure field on a second layer of the sample that is different from the first layer. The processor also receives a second measurement dataset related to a second set of measurement target features on the sample. The second set of measurement target features further includes one or more third features formed by exposing a third exposure field on a second layer of the sample, and one or more fourth features formed by exposing a fourth exposure field on a first layer of the sample.

Description

Technical Field

[0001] The present disclosure generally relates to overlay metrology measurements, and more particularly, to overlay metrology measurements that provide inter-field correction values.

Background Art

[0002] (Related Application) This application claims priority from U.S. Provisional Application No. 62 / 782,594, filed on Dec. 20, 2018, entitled "OVERLAY MARK DESIGN AND ALGORITHMIC APPROACHES FOR IMPROVING OVL MODELED FIELD TERMS AND CORRECTING SCANNER ERRORS", with Enna Leshinsky-Altshuller, Inna Tarshish-Shapir, Mark Ghinovker, Diana Shaphirov, Guy Ben Dov, Roie Volkovich, and Chris Steely as inventors, and incorporates the entire disclosure of the provisional application herein by reference.

[0003] Semiconductor manufacturing lines typically incorporate measurement and control processes at one or more points in the manufacturing process to monitor and control the creation of features on specific samples and / or features spanning multiple samples. For example, a common manufacturing process involves creating multiple chips dispersed across the entire surface of a sample (e.g., a semiconductor wafer), where each chip contains multiple patterned layers of material forming the device components. Each patterned layer may be formed by a series of steps including material deposition, lithography, and etching to form the desired pattern. Furthermore, the field of view of the lithography tools used in the exposure step (e.g., scanners, steppers, etc.) is substantially smaller than the dimensions of the sample, and each sample layer is exposed using multiple exposure fields dispersed across the entire sample. Therefore, it is desirable to monitor and control inter-field errors related to the dimensions and arrangement of the multiple exposure fields of the sample for exposing each layer, and overlay errors related to features on different sample layers within each exposure field, but this increases the number of measurement targets on the sample and reduces manufacturing throughput. However, typical measurement systems require separate targets and / or measurement techniques for overlay and field-to-field measurements. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2007 / 0058169 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Therefore, there is a need to provide systems and methods that support high-throughput overlay and field-to-field measurements. [Means for solving the problem]

[0006] A measurement system is disclosed according to one or more exemplary embodiments of this disclosure. In one exemplary embodiment, the system includes a control device communicatively coupled to a measurement tool. In another exemplary embodiment, the control device receives a measurement target design including at least a first feature formed by exposing a first exposure field of a sample using a lithography tool, and at least a second feature formed by exposing a second exposure field of the sample using a lithography tool. In another exemplary embodiment, the second exposure field partially overlaps with the first exposure field and further overlaps with the first exposure field at the location of the measurement target on the sample. In another exemplary embodiment, the control device receives measurement data relating to a measurement target fabricated according to the measurement target design. In another exemplary embodiment, the control device identifies one or more manufacturing errors during the fabrication of the measurement target based on the measurement data. In another exemplary embodiment, the control device generates one or more correctable values ​​based on the one or more manufacturing errors for adjusting one or more manufacturing parameters of the lithography tool in one or more subsequent lithography steps.

[0007] A pattern mask is disclosed according to one or more exemplary embodiments of the present disclosure. In one exemplary embodiment, the pattern mask includes one or more element pattern elements within the element region of the pattern mask. In another exemplary embodiment, the pattern mask includes a first set of measurement pattern elements in a first target region. In another exemplary embodiment, the pattern mask includes a second set of measurement pattern elements in a second target region. In another exemplary embodiment, the first and second target regions are located on opposite sides of the element region in a first direction. In another exemplary embodiment, the first and second sets of measurement pattern elements are configured to form at least a portion of a measurement target on a sample when the pattern mask is exposed on the sample by a first exposure field and a second exposure field, the second exposure field being provided such that the first target region of the first exposure field and the second target region of the second exposure field overlap at the location of the measurement target on the sample.

[0008] Measurement methods are disclosed according to one or more embodiments of this disclosure. In one exemplary embodiment, the method includes exposing a first exposure field on a sample using a lithography tool to form at least a first feature of a measurement target. In another exemplary embodiment, the method includes exposing a second exposure field on a sample using a lithography tool to form at least a second feature of a measurement target, wherein the second exposure field partially overlaps with the first exposure field, and the second exposure field overlaps with the first exposure field at the location of the measurement target on the sample. In another exemplary embodiment, the method includes generating measurement data corresponding to the measurement target using a measurement tool. In another exemplary embodiment, the method includes identifying one or more manufacturing errors during the manufacturing of the measurement target based on the measurement data. In another exemplary embodiment, the method includes generating one or more correctable values ​​for adjusting one or more manufacturing parameters of a lithography tool in one or more subsequent lithography steps based on one or more manufacturing errors.

[0009] The above-mentioned summary description and the following detailed description are provided for illustrative and explanatory purposes only and do not necessarily limit the invention as described in the claims. The accompanying drawings incorporated into the specification and constituting part of the specification illustrate embodiments of the invention and, together with the summary description, serve to explain the principles of the invention.

[0010] Many of the advantages of this disclosure will be more clearly understood by those skilled in the art by referring to the accompanying drawings. [Brief explanation of the drawing]

[0011] [Figure 1A] This is a conceptual diagram showing a manufacturing system according to one or more embodiments of the present disclosure. [Figure 1B] This is a conceptual diagram showing a lithography subsystem according to one or more embodiments of the present disclosure. [Figure 1C] A block diagram showing a measurement subsystem according to one or more embodiments of the present disclosure. [Figure 2] This diagram shows a conceptual top view of a sample, illustrating multiple superimposed exposure fields according to one or more embodiments of the present disclosure, corresponding to multiple lithography steps by a lithography subsystem involved in the fabrication of a particular sample layer. [Figure 3] This is a conceptual top view of a two-layer field detection overlay target according to one or more embodiments of the present disclosure. [Figure 4A] Figure 3 is a top view of a pattern mask according to one or more embodiments of the present disclosure, suitable for forming the field detection overlay target shown. [Figure 4B] This is a top view of a portion of the sample illustrating a process for creating a field-sensing overlay target based on the pattern mask of Figure 4A, using two orthogonal superimposed exposure fields, according to one or more embodiments of the present disclosure. [Figure 5A]A top view showing a pattern mask according to one or more embodiments of the present disclosure, suitable for forming the design of the field detection overlay target shown in Figure 3, the pattern mask comprising four cells, each cell containing a first layer of target features and a second layer of target features. [Figure 5B] This is a top view of a portion of the sample illustrating a process for creating a field-sensing overlay target based on the pattern mask of Figure 5A, using two orthogonal partially superimposed exposure fields, according to one or more embodiments of the present disclosure. [Figure 6A] A pattern mask according to one or more embodiments of the present disclosure, suitable for forming a nested box design of a field detection overlay target shown in Figure 3, wherein each portion of the target features of the first layer and the target features of the second layer are arranged in a series of nested boxes, and is a top view of the pattern mask. [Figure 6B] This is a top view of a portion of the sample illustrating a process for creating a field-detection overlay target based on the pattern mask of Figure 6A using a partially superimposed exposure field, according to one or more embodiments of the present disclosure. [Figure 7A] Figure 3 is a top view showing a pattern mask suitable for forming a "ruler" type design of the field detection overlay target shown in Figure 3, wherein the target features of the first layer and the parts of the target features of the second layer are arranged in a series of nested comb shapes. [Figure 7B] This is a top view of a portion of the sample illustrating a process for creating a field-detection overlay target based on the pattern mask of Figure 7A using a partially superimposed exposure field, according to one or more embodiments of the present disclosure. [Figure 8A] A top view of a pattern mask according to one or more embodiments of the present disclosure, suitable for forming the AIMid design of the field detection overlay target shown in Figure 3, wherein the target features of the first layer and the target features of the second layer are arranged in a staggered pattern. [Figure 8B] A top view showing a part of a sample, which illustrates a process of manufacturing a field detection overlay target based on the pattern mask of FIG. 8A using partially overlapping exposure fields according to one or more embodiments of the present disclosure. [Figure 9A] A pattern mask according to one or more embodiments of the present disclosure, suitable for forming the AIMid design of the field detection overlay target shown in FIG. 3, is a top view of the pattern mask in which the target features of the first layer and the target features of the second layer overlap to form a cross pattern. [Figure 9B] A top view showing a part of a sample, which illustrates a process of manufacturing a field detection overlay target based on the pattern mask of FIG. 9A using partially overlapping exposure fields according to one or more embodiments of the present disclosure. [Figure 10] A conceptual top view showing a single-layer field detection overlay target according to one or more embodiments of the present disclosure. [Figure 11A] A top view showing a pattern mask according to one or more embodiments of the present disclosure, suitable for forming the field detection overlay target shown in FIG. 10. [Figure 11B] A top view showing a part of a sample, which illustrates a process of manufacturing a field detection overlay target based on the pattern mask of FIG. 11A using partially overlapping exposure fields in two orthogonal directions according to one or more embodiments of the present disclosure. [Figure 12] A conceptual top view showing a single-layer field detection overlay target according to one or more embodiments of the present disclosure. [Figure 13A] A top view of a pattern mask according to one or more embodiments of the present disclosure, suitable for forming the features of the first layer. [Figure 13B] A top view showing a part of a sample, which illustrates a process of manufacturing the features of the first layer of a field detection overlay target based on the pattern mask of FIG. 13A using partially overlapping exposure fields according to one or more embodiments of the present disclosure. [Figure 13C] This is a top view of a pattern mask suitable for forming a second layer feature according to one or more embodiments of the present disclosure. [Figure 13D] This is a top view showing a portion of the sample, illustrating a process in which a partial superimposed exposure field is used to create a feature for the second layer of a field-sensing overlay target based on the pattern mask of Figure 13C, according to one or more embodiments of the present disclosure. [Figure 13E] This is a top view showing a portion of the sample, illustrating a process for creating a field-sensing overlay target based on the pattern mask of Figure 9A, using a partially superimposed exposure field in two orthogonal directions, according to one or more embodiments of the present disclosure. [Figure 14] This flowchart illustrates the steps performed in a field detection overlay measurement method according to one or more embodiments of the present disclosure. [Modes for carrying out the invention]

[0012] Next, the contents of this disclosure as shown in the accompanying drawings will be described in detail. This disclosure is illustrated and described specifically based on particular embodiments and their individual features. The embodiments described herein are illustrative and not limiting. Various modifications and changes can be made to form and details without deviating from the spirit and scope of this disclosure, as will be readily apparent to those skilled in the art.

[0013] Embodiments of this disclosure relate to systems and methods for providing overlay measurement and inter-field measurement (e.g., field-detected overlay measurement) on a common measurement target. Field-detected overlay measurement can provide data indicating at least one of overlay error and inter-field error by utilizing novel or conventional overlay measurement techniques on a field-detected overlay target. For example, the relative position of features on a field-detected overlay measurement target can provide data representing inter-field variation by detecting not only variation between overlapping exposures within a common exposure field, as in the case of a general overlay target, but also variation between adjacent exposure fields.

[0014] For the purposes of this disclosure, the term overlay measurement broadly means the measurement of alignment defects of features formed by two or more exposures to a common area of ​​a sample. In this regard, overlay measurement can provide measured values ​​of alignment of features formed by continuous exposures to a common sample layer (e.g., double patterning, triple patterning, etc.), as well as measurements of alignment of features formed on two or more layers of a sample. Also for the purposes of this disclosure, the term inter-field measurement broadly means the measurement of differences between features formed by two or more exposures in different fields (e.g., adjacent fields) on a sample. For example, inter-field errors may include, but are not limited to, inter-field overlapping errors or scaling errors. Accordingly, the systems and methods disclosed herein can provide measured values ​​for a wide range of processing errors in a common measurement step.

[0015] Some embodiments of this disclosure relate to field-sensing overlay targets suitable for simultaneously providing data representing overlay error and inter-field error. In this specification, a typical overlay measurement target is understood to be constructed by forming different parts of the target on either the same layer or multiple different layers through multiple exposures of the same area of ​​a sample (e.g., the same exposure field of a lithography tool). Therefore, the relative positions and / or relative dimensions of features formed by different exposure processes represent the alignment error of the lithography tool with respect to the exposure fields of the repeated exposure processes. In contrast, a field-sensing overlay target can be formed by multiple exposures of a common area of ​​a sample, where at least one exposure field partially overlaps with one or more other exposure fields used to generate the target. For example, one or more features of the measurement target may be formed by exposure of a first field on the sample, and one or more features may be formed by exposure of a second field on the sample, where the second field partially overlaps with the first field at the location of the measurement target. Therefore, the relative position and / or relative dimensions of the features of the field-detected overlay target are particularly affected by inter-field variations of the various exposure fields used to generate the target.

[0016] In this specification, field-sensing overlay targets may generally have the same design as non-field-sensing overlay targets. For example, suitable overlay measurement target designs include image-based measurement targets, which include, but are not limited to, Advanced Imaging Metrology (AIM) targets, AIM in-die (AIMid) targets, nested box targets, or multilayer AIMid (MLAIMid) targets. Another example of a suitable overlay measurement target design is a scatterometry-based overlay (SCOL) target. Thus, field-sensing overlay targets can be measured and characterized by novel or existing overlay measurement tools. However, the measurement algorithm used to extract information about the causes of errors in the measurements of field-sensing overlay targets may differ depending on the various different causes of errors measured by the field-sensing overlay target.

[0017] Further embodiments of this disclosure relate to photomasks suitable for fabricating field-sensing overlay targets. For example, a photomask may include an element region containing a pattern corresponding to an element feature, and one or more target regions around the element region. In particular, the target regions on both sides of the element region may include complementary areas of the field-sensing overlay target. Thus, a complete layer of the field-sensing overlay target may be fabricated by superimposed exposure (e.g., superimposed exposure fields) on the same sample, where the amount of superimposition is designed to generate a complementary pattern of the field-sensing overlay target.

[0018] Further embodiments of this disclosure cover generating correctable values ​​for a lithography tool based on both overlay data and inter-field data generated using a field-sensing overlay target. For example, feedforward correctable values ​​may be provided to the lithography tool during exposure of a later layer to compensate for variations measured in the current layer. As another example, feedback correctable values ​​can be provided to the lithography tool to mitigate variations (drift) over time.

[0019] Furthermore, this specification considers that field-sensing overlay measurement can be suitable for measuring, controlling, and / or mitigating various sources of manufacturing errors. Such manufacturing errors include, but are not limited to, variations in the shape of the photomask and / or sample, stress on the photomask and / or sample, surface tension effects on the photomask and / or sample, or errors related to the lithography tool itself. Therefore, correctable values ​​based on field-sensing overlay measurement can provide highly accurate and efficient control of the lithography process.

[0020] Next, with reference to Figures 1A to 14, a field detection overlay measurement system and method will be described in more detail according to one or more embodiments of this disclosure.

[0021] Figure 1A is a conceptual diagram showing a manufacturing system 100 according to one or more embodiments of the present disclosure. In one embodiment, the system 100 includes a lithography subsystem 102 for imaging one or more pattern elements (e.g., element pattern elements, measurement target pattern elements, etc.) of a pattern mask on a sample in a lithographic manner. The lithography subsystem 102 may include, but is not limited to, any lithography tool known in the art, such as a scanner or a stepper. In another embodiment, the system 100 includes a measurement subsystem 104 for characterizing one or more features on a sample. The measurement subsystem 104 may include an overlay measurement tool suitable for measuring the relative position of sample features (e.g., features of a field-sensing overlay target). In one embodiment, the measurement subsystem 104 includes an image-based measurement tool for measuring measurement data based on the generation process of one or more images of the sample. In another embodiment, the measurement subsystem 104 includes a scantometry-based measurement system for measuring measurement data based on the scattering of light from the sample (reflection, diffraction, diffuse scattering, etc.). In another embodiment, the system 100 includes a control device 106. In other embodiments, the control unit 106 includes one or more processors 108 configured to execute program instructions held in the memory medium 110. In this regard, one or more processors 108 of the control unit 106 can execute any of the various process steps described throughout this disclosure.

[0022] One or more processors 108 of the control unit 106 may include any element processors known in the art. In this sense, one or more processors 108 may include microprocessor-type devices configured to execute algorithms and / or instructions. In one embodiment, one or more processors 108 may consist of a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, or any other computer system (e.g., a network computer) configured to execute a program built to drive system 100, as described throughout this disclosure. The term “processor” is also broadly defined and includes any device having one or more element processors that execute program instructions obtained from a non-temporary memory medium 110. Furthermore, the steps described throughout this disclosure may be performed by a single control unit 106 or by multiple control units instead. Furthermore, control unit 106 may include one or more control units housed in a common housing or in multiple housings. This allows any one control unit, or a combination of multiple control units, to be individually packaged as modules suitable for integration into system 100. Furthermore, the control device 106 can analyze the data received from the detector 132 and send the analyzed data to additional components within the system 100 (e.g., the lithography subsystem 102) or to an external source.

[0023] The memory medium 110 may include any storage medium known in the art that is suitable for storing program instructions executable on one or more associated processors 108. For example, the memory medium 110 may include a non-temporary memory medium. Other examples include, but are not limited to, read-only memory, random-access memory, magnetic or optical memory devices (e.g., disks), magnetic tapes, solid-state drives, etc. Furthermore, the memory medium 110 may be housed within a common control unit housing having one or more processors 108. In one embodiment, the memory medium 110 may be located remotely from the physical locations of one or more processors 108 and the control unit 106. For example, one or more processors 108 of the control unit 106 may access remote memory (e.g., a server) accessible from a network (e.g., the Internet, an intranet, etc.). Thus, the foregoing description should be interpreted as merely an example and not a limitation to the present invention.

[0024] Figure 1B is a conceptual diagram showing a lithography subsystem 102 according to one or more embodiments of the present disclosure. In one embodiment, the lithography subsystem 102 includes a lithography illumination source 112 configured to generate an illumination beam 114. One or more illumination beams 114 may include one or more selected wavelengths of light, and may include, but are not limited to, ultraviolet (UV) radiation, visible light radiation, or infrared (IR) radiation.

[0025] Illumination from the lithography illumination source 112 may have any spatial distribution (e.g., illumination pattern). For example, the lithography illumination source 112 may be, but is not limited to, a unipolar illumination source, a bipolar illumination source, a C-quad illumination source, a quasar illumination source, or a free-form illumination source. In this regard, the lithography illumination source 112 may generate an on-axis illumination beam 114 in which the illumination light propagates along (or parallel to) the optical axis 116, and / or any number of off-axis illumination beams 114 in which the illumination light propagates at an angle to the optical axis 116.

[0026] To further elaborate, for the purposes of this disclosure, the illumination poles of the lithography illumination source 112 may represent illumination from a specific location. In this regard, each spatial position of the lithography illumination source 112 (for example, a spatial position relative to the optical axis 116) can be considered an illumination pole. Furthermore, the illumination poles may have any shape or size known in the art. In addition, the lithography illumination source 112 is considered to have an irradiation profile corresponding to the distribution of illumination poles.

[0027] Furthermore, the lithography illumination source 112 may generate illumination beams 114 in any manner known in the art. For example, illumination beams 114 may be formed as illumination from the illumination poles of the lithography illumination source 112 (e.g., a portion of the illumination profile of the lithography illumination source 112). As another example, the lithography illumination source 112 may include multiple illumination sources that generate multiple illumination beams 114.

[0028] In other embodiments, the lithography subsystem 102 includes a mask support device 118 configured to hold the pattern mask 120 in place. In other embodiments, the lithography subsystem 102 includes a set of projection optics 122 configured to project an image of the pattern mask 120, illuminated by one or more illumination beams 114, onto a sample 124 placed on a sample stage 126, thereby generating printed pattern elements corresponding to the image of the pattern mask 120. In other embodiments, the mask support device 118 may be configured to drive or position the pattern mask 120. For example, the mask support device 118 can drive the pattern mask 120 to a specified position relative to the projection optics 122 of system 100.

[0029] 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, sample 124 may include a resist layer 128. In this regard, a set of projection optics 122 can project an image of the pattern mask 120 onto the resist layer 128 to expose the resist layer 128, and in a subsequent etching step, the exposed material can be removed (e.g., positive etching) or the unexposed material can be removed (e.g., negative etching) to provide printed features on sample 124. The pattern mask 120 may also 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) in which pattern elements are positively imaged as printed pattern elements. As an 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.).

[0030] The control device 106 may be communicatively connected to any element or combination of elements within the lithography subsystem 102, and may, but is not limited to, being connected to a mask support device 118 and / or a sample stage 126 to direct pattern elements on the pattern mask 120 to be transferred to a sample 124, or being connected to a lithography illumination source 112 to control one or more features of the illumination beam 114.

[0031] Figure 1C is a block diagram of a measurement subsystem 104 according to one or more embodiments of the present disclosure. The system 100 may generate one or more images corresponding to light arriving from a sample 124 (e.g., sample light 130) on at least one detector 132 using any method known in the art. In one embodiment, the detector 132 is positioned in the field of view to generate an image of one or more features on the sample 124. In this respect, the system 100 can operate as an image-based overlay measurement tool. In another embodiment, the detector 132 is positioned in the pupil plane to generate an image based on the angle of light arriving from the sample 124 (e.g., based on reflection, diffraction, scattering, etc.). In this respect, the system 100 can operate as a scantometry-based measurement tool.

[0032] In one embodiment, the measurement subsystem 104 includes a measurement illumination source 134 that generates a measurement illumination beam 136. The measurement illumination source 134 may be identical to the lithography illumination source 112, or it may be a separate illumination source configured to generate an independent measurement illumination beam 136. The measurement illumination beam 136 may include, but is not limited to, one or more selected wavelengths of light, including vacuum ultraviolet (VUV) radiation, deep ultraviolet (DUV) radiation, ultraviolet (UV) radiation, visible light radiation, or infrared (IR) radiation. The measurement illumination source 134 can further generate a measurement illumination beam 136 that includes any range of selected wavelengths. In another embodiment, the measurement illumination source 134 may include a spectrally tunable illumination source that generates a measurement illumination beam 136 having an adjustable spectrum.

[0033] The measurement illumination source 134 may further generate a measurement illumination beam 136 having a time profile. For example, the measurement illumination source 134 can generate a continuous measurement illumination beam 136, a pulsed measurement illumination beam 136, or a modulated measurement illumination beam 136. The measurement illumination beam 136 may also be transmitted from the measurement illumination source 134 by free-space propagation or by guided light (e.g., optical fiber, optical conductor, etc.).

[0034] In other embodiments, the measurement illumination source 134 delivers a measurement 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 optics 142 suitable for modulating and / or adjusting the measurement illumination beam 136. For example, one or more illumination optics 142 could be, 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-optic shutters, acousto-optic shutters, etc.). As an example, one or more illumination optics 142 may include an aperture diaphragm to control the angle of illumination on the sample 124, and / or a field diaphragm to control the spatial range of illumination on the sample 124. In one example, the illumination path 138 includes an aperture diaphragm positioned in the conjugate plane of the back focal plane of the objective lens 144 to provide telecentric illumination of the sample. In another embodiment, the system 100 includes an objective lens 144 that focuses the measurement illumination beam 136 onto the sample 124.

[0035] In other embodiments, sample 124 is placed on sample stage 146. Sample stage 146 may include any device suitable for positioning sample 124 within system 100. For example, sample stage 146 may include a linear translation table, a rotary table, a tip / tilt table, etc.

[0036] In other embodiments, the detector 132 is configured to capture radiation arriving from the sample 124 through the focusing path 148 (e.g., sample light 130). For example, the focusing path 148 may include, but is not required to include, a focusing lens (e.g., an objective lens 144 as shown in Figure 1C) or one or more additional focusing path lenses 150. In this regard, the detector 132 can receive radiation reflected or scattered from the sample (e.g., reflected or scattered by specular reflection or diffuse reflection, etc.) or radiation generated by the sample 124 (e.g., light emission related to absorption of the measurement illumination beam 136, etc.).

[0037] The focusing path 148 may further include any number of focusing optical components 152 that transmit and / or modulate the illumination focused by the objective lens 144, the focusing optical components 152 being, but not limited to, one or more focusing path lenses 150, one or more filters, one or more polarizers, or one or more beam blocks. The focusing path 148 may also include a field diaphragm to control the spatial range of the sample imaged on the detector 132, or an aperture diaphragm to control the angular range of illumination from the sample used to generate an image on the detector 132. In other embodiments, the focusing path 148 includes optical components, an aperture diaphragm positioned in the conjugate plane of the back focal plane of the objective lens 144 to provide telecentric imaging of the sample.

[0038] The detector 132 may include any type of optical detector known in the art that is suitable for measuring the illumination received from the sample 124. For example, the detector 132 may include a sensor suitable for generating one or more images of a stationary sample 124 (e.g., a sample in stationary 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 an example, the detector 132 may include, but is not limited to, a line sensor or a time delay and integration (TDI) sensor that is suitable for generating one or more images of the sample 124 during operation (e.g., during the scanning mode of operation).

[0039] In other embodiments, the detector 132 may include a spectroscopic detector suitable for identifying the wavelength of radiation arriving from the sample 124. In other embodiments, the system 100 may include a plurality of detectors 132 (for example, corresponding to a plurality of beam paths formed by one or more beam splitters), which facilitates multiple measurement processes by the system 100.

[0040] In one embodiment, as shown in Figure 1C, the system 100 includes a beam splitter 154 positioned so that the objective lens 144 can deliver the measurement illumination beam 136 to the sample 124 while simultaneously collecting radiation arriving from the sample 124. In this case, the system 100 may be configured in reflected illumination mode.

[0041] In other embodiments, the control unit 106 is communicatively connected to one or more components of the system 100. In this case, the control unit 106 can send and receive data from any component of the system 100. For example, the control unit 106 may be configured to receive data including one or more images obtained from the detector 132, but is not limited to this configuration.

[0042] Figure 2 is a conceptual top view of sample 124 illustrating a plurality of superimposed exposure fields 202 according to one or more embodiments of this disclosure, associated with a plurality of lithography steps by a lithography subsystem 102 involved in the fabrication of a particular sample layer. In one embodiment, a pattern mask 120 is imaged onto each exposure field 202. Alternatively, the same pattern mask 120 may be repeatedly imaged onto each exposure field 202, or a plurality of pattern masks 120 may be imaged onto a selection of exposure fields 202. However, it should be understood that Figure 2 is not drawn to scale. Conversely, the parameters in Figure 2, such as the dimensions of each exposure field 202 relative to the dimensions of sample 124, the number of exposure fields 202, or the amount of superimposition of adjacent exposure fields 202, are selected for illustrative purposes only and should not be interpreted as limiting.

[0043] In one embodiment, as shown in Figure 2, adjacent exposure fields 202 may overlap to form an overlapping region 204 distributed from edge to edge of sample 124. Since element features (e.g., features corresponding to the chip distributed from edge to edge of sample 124) can be fabricated in any of the non-overlapping regions 206, a field-sensing overlay target or each portion thereof on a particular sample layer may be formed by exposure from adjacent overlapping exposure fields 202 to any of the overlapping regions 204. In contrast, as used herein, a typical overlay measurement target is recognized as being formed using fully overlapping exposure fields 202 involving different lithography steps in the same or different layers.

[0044] In other embodiments, the pattern of the exposure field 202 may be replicated in a series of lithography steps associated with the manufacturing process. For example, a first set of pattern elements corresponding to a first sample layer may be fabricated using a series of steps including a material deposition step, a lithography step using the pattern of the exposure field 202 (e.g., as shown in Figure 2), and an etching step. A second set of pattern elements corresponding to a second sample layer may be fabricated using a series of additional material deposition steps, a lithography step using the pattern of the exposure field 202, an etching step, etc., during which the patterns of each exposure field 202 corresponding to the first and second sample layers are aligned. A similar process may be performed by multiple alignment exposures on a single sample layer (e.g., multiple exposures such as a double patterning step).

[0045] Next, with reference to Figures 3 to 13E, field-sensing measurement targets and their formation will be described in detail according to one or more embodiments of this disclosure. In this specification, a field-sensing measurement target may include features on any number of sample layers formed from any number of superimposed exposure fields 202. Figures 3 to 9B show a non-limiting example of a two-layer field-sensing overlay target, in which features corresponding to a first sample layer are formed using one exposure field 202, and features corresponding to a second sample layer are formed using an adjacent superimposed exposure field 202. In these designs, the relative position and / or relative dimensions of the features of the first layer relative to the features of the second layer change, in particular, depending on the field-to-field variation between multiple lithography steps for different sample layers. Figures 10 to 11B show a non-limiting example of a single-layer field-sensing overlay target. In this design, the relative position and / or relative dimensions of the features of the first layer relative to the features of the second layer change, in particular, depending on the field-to-field variation between multiple lithography steps for a single sample layer. Figures 12 to 13E show a non-limiting example of a two-layer field-sensing overlay target formed using four exposures across two exposure fields 202. In this example, the first layer features are fabricated using adjacent exposure fields 202 in a manner similar to the examples in Figures 10 to 11B, and the second layer features are fabricated using the same adjacent exposure fields 202 used for the first layer features. In this design, target areas containing features from different layers, formed from fully overlapping exposure fields 202, can function as conventional overlay targets and provide data representing the alignment and / or scaling errors of the lithography tool during sequential exposures of each exposure field 202. Target areas containing features formed from partially overlapping exposure fields 202 can provide data indicating errors between fields. It should also be understood that the examples herein are presented for illustrative purposes only and should not be construed as limiting.For example, other designs of one- or two-layer field-sensing overlay targets that provide conventional overlay data and / or inter-field data also fall within the spirit and scope of this disclosure. As another example, a field-sensing overlay target may include features on three or more sample layers formed using at least one exposure field 202 which overlaps only partially with other exposure fields 202 at the location of the target.

[0046] Figure 3 is a conceptual top view showing a two-layer field-sensing overlay target 300 according to one or more embodiments of the present disclosure. In one embodiment, the field-sensing overlay target 300 includes a first-layer target feature 302 formed using a first exposure field 202 and a second-layer target feature 304 formed using a second exposure field, where the second exposure field 202 partially overlaps with the first exposure field 202. For example, using the example in Figure 2, the first-layer target feature 302 can be associated with exposure field 202a and the second-layer target feature 304 can be associated with exposure field 202b. Thus, the first-layer target feature 302 and the second-layer target feature 304 are complementary parts of the complete field-sensing overlay target 300.

[0047] It should be understood that the layout of the field detection overlay target 300 in Figure 3 is intended as an example, not an limitation. The target features 302 of the first layer and the target features 304 of the second layer may be arranged in any configuration suitable for overlay measurement. For example, the layout of the target features 302 of the first layer and the target features 304 of the second layer is not limited to the diagram in Figure 3 in which the target features 302 of the first layer and the target features 304 of the second layer each contain two cells and are distributed along intersecting diagonals. Rather, the target features 302 of the first layer and the target features 304 of the second layer can be distributed in any number of cells in any pattern suitable for overlay measurement. In one example, the target features 302 of the first layer and the target features 304 of the second layer may be completely or partially superimposed. Also, either the target features 302 of the first layer or the target features 304 of the second layer may be segmented along one or more directions.

[0048] Therefore, this specification further assumes that the relative positions of features formed by different exposure processes can be determined using any technique, and these relative positions may be affected by various causes of errors, including overlay errors and inter-field errors already described herein. For example, the position of the target feature 302 in the first layer may be directly compared with the target feature 304 in the second layer. As another example, the centers of symmetry corresponding to the target feature 302 in the first layer and the target feature 304 in the second layer (e.g., centers of rotational symmetry, mirror symmetry, etc.) may be compared.

[0049] Figures 4A to 9B show various designs of the field-detection overlay target 300 exemplified in Figure 3, along with corresponding pattern masks 120 suitable for forming various designs using adjacent partially superimposed exposure fields 202. However, it should be understood that the designs of the field-detection overlay target 300 exemplified in Figures 4A to 9B are shown for illustrative purposes only and should not be construed as limiting. In this specification, it is assumed that any overlay target design can be adapted to field detection by creating complementary regions using adjacent partially superimposed exposure fields 202.

[0050] Figure 4A is a top view of a pattern mask 402 (for example, corresponding to the pattern mask 120 in Figure 1B) according to one or more embodiments of the present disclosure, suitable for forming the field-sensing overlay target 300 shown in Figure 3. In one embodiment, the pattern mask 402 includes an element region 404 containing a pattern of element features (not shown) corresponding to the semiconductor element to be fabricated. In another embodiment, the pattern mask 402 includes complementary portions of the field-sensing overlay target 300 within the boundary 406 of the opposing imaging regions on both sides of the element region 404. For example, the pattern mask 402 includes complementary portions of the field-sensing overlay target 300 along the horizontal axis for forming a complete field-sensing overlay target 300 using horizontally adjacent exposure fields 202, and further includes complementary portions of the field-sensing overlay target 300 along the vertical axis for forming a complete field-sensing overlay target 300 using vertically adjacent exposure fields 202. In particular, the pattern elements 408 corresponding to the target feature 302 of the first layer are arranged on the left and upper sides of the element region 404, and the pattern elements 410 corresponding to the target feature 304 of the second layer are arranged on the right and lower sides of the element region 404.

[0051] Figure 4B is a partial top view of sample 124 illustrating the fabrication of a field-sensing overlay target 300 based on the pattern mask 402 of Figure 4A, formed in two orthogonal directions using superimposed exposure fields 202, according to one or more embodiments of the present disclosure. In one embodiment, each exposure field 202 contains an image of the pattern mask 402. The spacing and superimposition of adjacent exposure fields 202 can be selected such that complementary portions of the field-sensing overlay target 300 overlap on sample 124 to form a complete field-sensing overlay target 300 in the superimposed region 204, while element features corresponding to the element region 404 of the pattern mask 402 are formed in the non-overlapping region 206.

[0052] For example, a field-detection overlay target 300a is formed using a first layer of target features 302 obtained from a first exposure field 202 (e.g., exposure field 202a) and a second layer of target features 304 obtained from a second exposure field 202 (e.g., exposure field 202b). As another example, a field-detection overlay target 300b is formed using a first layer of target features 302 obtained from a first exposure field 202 (e.g., exposure field 202a) and a second layer of target features 304 obtained from a third exposure field 202 (e.g., exposure field 202c).

[0053] Next, with reference to Figures 5A to 9B, various designs of the field-sensing overlay target and their corresponding pattern masks will be described in more detail according to one or more embodiments of this disclosure. The description of the pattern mask 402 for fabricating the field-sensing overlay target 300 corresponding to Figures 4A and 4B, and the description of the partial superposition exposure of the pattern mask 402 on sample 124, can be applied to the target designs shown in Figures 5A to 9B.

[0054] Figure 5A is a top view of a pattern mask 502 (e.g., corresponding to pattern mask 120 in Figure 1B) suitable for forming the design of the field-sensing overlay target 300 shown in Figure 3, and shows a pattern mask 502 according to one or more embodiments of the present disclosure, which includes four cells in which portions of the target features 302 of the first layer and the target features 304 of the second layer are arranged in each cell. Specifically, pattern elements 408 corresponding to the target features 302 of the first layer are arranged on the left and lower sides of the element region 404, and pattern elements 410 corresponding to the target features 304 of the second layer are arranged on the right and upper sides of the element region 404. Figure 5B is a partial top view of sample 124, illustrating the fabrication of a field-sensing overlay target 300 based on the pattern mask of Figure 5A, which is formed in two orthogonal directions using a partially superimposed exposure field 202, according to one or more embodiments of the present disclosure. The relative positions of the target feature 302 in the first layer and the target feature 304 in the second layer in this design can be determined by comparing their respective centers of rotational symmetry, but are not necessarily limited to this. For example, the target feature 302 in the first layer and the target feature 304 in the second layer are 90 degrees rotationally symmetric. However, this specification considers, to be in the spirit and scope of this disclosure, designs including other types of symmetry, such as 180 degrees rotational symmetry or mirror symmetry, but are not limited to these.

[0055] Figure 6A is a top view of a pattern mask 602 (e.g., corresponding to pattern mask 120 in Figure 1B) suitable for forming the nested box design of the field-sensing overlay target 300 shown in Figure 3, showing a pattern mask 602 according to one or more embodiments of the present disclosure, in which the portions of the first layer target features 302 and the second layer target features 304 are arranged in a series of nested boxes. Figure 6B is a partial top view of sample 124, illustrating the fabrication of a field-sensing overlay target 300 based on the pattern mask 602 of Figure 6A, formed using a partially superimposed exposure field 202 according to one or more embodiments of the present disclosure. Although not shown in the figure, the field-sensing overlay target 300 may be formed by multiple partial superimposed exposures of the pattern mask 602 along the vertical direction of Figure 6B, in a manner similar to that shown in Figures 4B and 5B.

[0056] Figure 7A is a top view of a pattern mask 702 (e.g., corresponding to pattern mask 120 in Figure 1B) suitable for forming a "Ruler" type design of the field-detection overlay target 300 shown in Figure 3, where the portions of the first layer target features 302 and the second layer target features 304 are arranged in a series of nested comb shapes, representing the pattern mask 702 according to one or more embodiments of the present disclosure. Figure 7B is a partial top view of sample 124, illustrating the fabrication of a field-detection overlay target 300 based on the pattern mask 702 of Figure 7A, formed using a partially superimposed exposure field 202 according to one or more embodiments of the present disclosure. Although not shown in the figure, the field-detection overlay target 300 may also be formed by multiple partial superimposed exposures of the pattern mask 702 along the vertical direction of Figure 7B, in a manner similar to that shown in Figures 4B and 5B.

[0057] Figure 8A is a top view of a pattern mask 802 (e.g., corresponding to pattern mask 120 in Figure 1B) suitable for forming the AIMid design of the field-sensing overlay target 300 shown in Figure 3, showing a pattern mask 802 according to one or more embodiments of the present disclosure, in which the target features 302 of the first layer and the target features 304 of the second layer are arranged in a staggered pattern. Figure 8B is a partial top view of sample 124, illustrating the fabrication of a field-sensing overlay target 300 based on the pattern mask 802 of Figure 8A, formed using a partially superimposed exposure field 202 according to one or more embodiments of the present disclosure. Although not shown in the figure, the field-sensing overlay target 300 may be formed by multiple partial superimposed exposures of the pattern mask 802 along the vertical direction of Figure 8B, in a manner similar to that shown in Figures 4B and 5B.

[0058] Figure 9A is a top view of a pattern mask 902 (e.g., corresponding to pattern mask 120 in Figure 1B) suitable for forming the AIMid design of the field-sensing overlay target 300 shown in Figure 3, and shows a pattern mask 902 according to one or more embodiments of the present disclosure, in which the target features 302 of the first layer and the target features 304 of the second layer overlap to form a cross pattern. Figure 9B is a partial top view of sample 124, illustrating the fabrication of a field-sensing overlay target 300 based on the pattern mask 902 of Figure 9A, formed using a partially superimposed exposure field 202 according to one or more embodiments of the present disclosure. Although not shown in the figure, the field-sensing overlay target 300 may be formed by multiple partial superimposed exposures of the pattern mask 902 along the vertical direction of Figure 9B, in a manner similar to that shown in Figures 4B and 5B.

[0059] Next, with reference to Figures 10 to 11B, a single-layer field-sensing overlay target 1000 will be described according to one or more embodiments of the present disclosure. Figure 10 is a conceptual top view of a single-layer field-sensing overlay target 1000 according to one or more embodiments of the present disclosure. The single-layer field-sensing overlay target 1000 of Figure 10 is similar to the two-layer field-sensing overlay target 300 shown in Figure 3, but differs in that all features are formed using an exposure field 202 corresponding to a common sample layer. Specifically, the single-layer field-sensing overlay target 1000 may include a first set of target features 1002 corresponding to a first exposure field 202 (e.g., exposure field 202a) and a second set of target features 1004 corresponding to a second exposure field 202 (e.g., exposure field 202b or exposure field 202c).

[0060] Figure 11A is a top view of a pattern mask 1102 (for example, corresponding to pattern mask 120 in Figure 1B) according to one or more embodiments of the present disclosure, suitable for forming the field-sensing overlay target 1000 shown in Figure 10. Specifically, pattern element 1104 corresponds to a first set of target features 1002, and pattern element 1106 corresponds to a second set of target features 1004. Figure 11B is a partial top view of sample 124, showing the fabrication of a field-sensing overlay target 1000 based on the pattern mask 1102 of Figure 11A, formed in two orthogonal directions using a partially superimposed exposure field 202, according to one or more embodiments of the present disclosure.

[0061] Next, with reference to Figures 12 to 13E, a two-layer field-sensing overlay target 1200 will be described according to one or more embodiments of the present disclosure. Figure 12 is a conceptual top view of a single-layer field-sensing overlay target 1200 according to one or more embodiments of the present disclosure.

[0062] In one embodiment, the field-detection overlay target 1200 is formed by four exposures. For example, the field-detection overlay target 1200 may include a first set of first layer features 1202 formed from a first exposure field 202 (e.g., exposure field 202a) and a second set of first layer features 1204 formed from a second exposure field (e.g., exposure field 202b or exposure field 202c) that partially overlaps with the first exposure field. The field-detection overlay target 1200 may further include a first set of second layer features 1206 formed from a first exposure field (e.g., exposure field 202a) and a second set of second layer features 1208 formed from a second exposure field (e.g., exposure field 202b or exposure field 202c).

[0063] Figure 13A is a top view of a pattern mask 1302 (corresponding to, for example, the pattern mask 120 in Figure 1B) according to one or more embodiments of the present disclosure, which is suitable for forming first layer features (e.g., a first set of first layer features 1202 and a second set of first layer features 1204). Specifically, pattern element 1304 corresponds to the first set of first layer features 1202, and pattern element 1306 corresponds to the second set of first layer features 1204.

[0064] Figure 13B is a partial top view of sample 124, illustrating the fabrication of a first-layer feature of a field-sensing overlay target 1200 based on the pattern mask 1302 of Figure 13A, formed using a partially superimposed exposure field 202 (e.g., exposure fields 202a,b in the first layer lithography step) according to one or more embodiments of the present disclosure.

[0065] Figure 13C is a top view of a pattern mask 1308 (corresponding to, for example, the pattern mask 120 in Figure 1B) according to one or more embodiments of the present disclosure, which is suitable for forming second layer features (e.g., a first set of second layer features 1206 and a second set of second layer features 1208). Specifically, pattern element 1310 corresponds to the first set of second layer features 1206, and pattern element 1312 corresponds to the second set of second layer features 1208.

[0066] Figure 13D is a partial top view of sample 124 illustrating the fabrication of a second layer feature of a field-sensing overlay target 1200 based on the pattern mask 1308 of Figure 13C, formed using a partially superimposed exposure field 202 (e.g., exposure fields 202a,b in the second layer lithography step) according to one or more embodiments of the present disclosure. The exposure fields 202a,b in the second layer lithography step may also be fully superimposed with the corresponding exposure fields 202a,b in the first layer lithography step.

[0067] Figure 13E is a partial top view of sample 124, illustrating the fabrication of a field-sensing overlay target 1200 based on the pattern masks 1302 and 1308 of Figures 13A and 13C, formed in two orthogonal directions using a partially superimposed exposure field 202, according to one or more embodiments of the present disclosure.

[0068] As shown in Figures 12 to 13E, the field-sensing overlay target 1200 can provide both general overlay data and inter-field data relevant to 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 from superimposed exposure fields 202 (e.g., exposure field 202a) that completely overlap in the first and second layers, the relative position and / or relative dimensions of the first set of first layer features 1202 with respect to the first set of second layer features 1206 can be provided by the general overlay target and can indicate general overlay errors regarding the alignment of lithography steps across multiple layers. Similarly, the second set of first layer features 1204 and the second set of second layer features 1208 can also provide similar data.

[0069] However, the field detection overlay target 1200 can also provide data representing various inter-field errors. For example, the pattern mask 1302 in Figure 13A and the pattern mask 1308 in Figure 13C both function in the same manner as the pattern mask 1102 shown in Figure 11A. Therefore, the relative position and / or relative dimensions of the first layer feature 1202 of the first set with respect to the first layer feature 1204 of the second set can indicate inter-field errors in the first layer, while the relative position and / or relative dimensions of the second layer feature 1206 of the first set with respect to the second layer feature 1208 of the second set can indicate inter-field errors in the second layer. Furthermore, the field detection overlay target 1200 can provide data representing inter-field errors spanning multiple layers. For example, the relative position and / or relative dimensions of the first layer feature 1202 of the first set to the second layer feature 1208 of the second set can indicate inter-field errors across multiple layers, similar to the data obtained by the targets illustrated in Figures 3 to 13E. Similar data can also be obtained based on the first layer feature 1204 of the second set and the second layer feature 1208 of the second set.

[0070] As already explained herein, Figures 3 to 13E are provided for illustrative purposes only and should not be construed as limiting. Rather, a field-sensing overlay target can include any number of features formed by any number of exposures, provided that at least some of the target features are formed from exposure fields 202 that partially overlap with other exposure fields 202 used to form the target. Furthermore, a field-sensing overlay target can include combinations of features illustrated herein. For example, a field-sensing overlay target may include features in three or more sample layers.

[0071] Figure 14 is a flowchart illustrating the steps performed in Method 1400 of field-sensing overlay measurement according to one or more embodiments of the present disclosure. The applicant acknowledges that embodiments and feasible techniques already described herein in the context of System 100 should be construed as extending to Method 1400. However, it should be noted that Method 1400 is not limited to the configuration of System 100.

[0072] In one embodiment, the method includes step 1402 of exposing a first exposure field of a sample with a lithography tool to form at least a first feature of a measurement target (e.g., a field-detection overlay target). In another embodiment, the method includes step 1404 of exposing a second exposure field on the sample using a lithography tool that partially overlaps the first exposure field to form at least a second feature of the measurement target. Specifically, the second exposure field may overlap the first exposure field at the location of the measurement target on the sample. Thus, the first and second features of the measurement target can each form complementary regions of the measurement target.

[0073] In this specification, the first exposure field may be located in the same layer as the second exposure field, or in a different layer. Therefore, the first and second features may be features of the same or different layers of the sample. The method may also include additional exposures to form other features of the measurement target, each additional exposure completely or partially overlapping with other exposures used to generate features of the measurement target.

[0074] For example, Figures 3 to 13E show various non-limiting examples of performing steps 1402 and 1404 using system 100.

[0075] In other embodiments, the method includes step 1406 of generating measurement data corresponding to a measurement target using a measurement tool (e.g., measurement subsystem 104). In other embodiments, the method includes step 1408 of identifying one or more manufacturing errors during the fabrication of the measurement target based on the measurement data. For example, at least one of the relative position and relative dimensions of several features of the measurement target (e.g., a first feature, a second feature, any additional features, etc.) may indicate manufacturing errors during the fabrication of the measurement target, including but not limited to errors related to the lithography tool (e.g., field scaling error, inter-field alignment error, sample / mask alignment error, overlay error, etc.) or errors related to the sample (e.g., sample stress, sample defects, etc.).

[0076] In another embodiment, the method includes step 1410 of generating one or more correctable values ​​based on one or more manufacturing errors for adjusting one or more manufacturing parameters of a lithography tool in one or more subsequent lithography steps.

[0077] Step 1410 may include generating correctable values ​​to be used in any combination of feedback control or feedforward control of a lithography tool used to fabricate a measurement target (and thus, element features on the sample). For example, a feedforward correctable value may be provided to the lithography tool to compensate for variations measured in the current sample layer during exposure of a subsequent layer of the same sample. As another example, a feedback correctable value may be provided to the lithography tool to mitigate variations over time (e.g., drift). Such correctable values ​​may be applied to different parts of the same sample, to different samples within the same lot, or to multiple samples existing across multiple lots.

[0078] This specification considers that a measurement target generated by Method 1400 (e.g., a field-sensing overlay target) that provides detection capability for inter-field errors can enable the generation of correctable values ​​for lithography tools more accurately and effectively than a general overlay target. For example, the field-sensing measurement target disclosed herein makes it easy to determine a High-Resolution Reference Point (HRRP) to suppress overlay errors between joined target cells caused by different exposure fields. As another example, the field-sensing measurement target described herein may be printed along the edges of a field to facilitate patterning wrap geometry (PWG) measurement within and between fields, or to assist in the fine-tuning or verification of existing PWG techniques.

[0079] The contents described herein include, in some cases, other components included in other components, or other components combined with other components. It should be understood that the configurations described herein are merely examples, and in practice, numerous other configurations can be implemented to achieve the same function. Conceptually, configurations of components that achieve the same function are effectively "associated" in such a way that the desired function is realized. Therefore, two components combined in this specification to achieve a particular function, regardless of whether they are components or intermediate components, can be recognized as "associated" with each other in such a way that the desired function is realized. Similarly, two such associated components can be seen as "connected" or "combined" in such a way that the desired function is realized, and two components that can be associated in such a way can also be seen as "combinable" with each other in such a way that the desired function is realized. Specific examples of combinable components include, but are not limited to, physically interactable components, components that are physically interacting, wirelessly interactable components, components that are wirelessly interacting, logically interactable components, and / or logically interacting components.

[0080] We are confident that the present disclosure and its numerous accompanying advantages will be understood by the foregoing description. It will also be apparent that the form, structure, and arrangement of the components can be modified without deviating from the disclosed content or sacrificing any of the advantages of the disclosed materials. The described forms are merely illustrative, and the following claims are intended to imply and encompass the aforementioned modifications. It will also be understood that the present invention is defined by the accompanying claims.

Claims

1. A measurement system including a control device that is communicatively connected to a measurement tool, The control device includes one or more processors configured to execute program instructions, and the program instructions are directed to the one or more processors. Receiving a first measurement dataset associated with a first set of measurement target features on a sample, wherein the first set of measurement target features includes one or more first features formed by exposing a first exposure field on a first layer of the sample using a lithography tool, and one or more second features formed by exposing a second exposure field on a second layer of the sample that is different from the first layer using the lithography tool, wherein the first exposure field and the second exposure field are overlapping exposure fields that completely overlap in the first and second layers. Receiving a second measurement dataset relating to a second set of measurement target features on the sample, wherein the second set of measurement target features includes one or more third features formed by exposing a third exposure field on the first layer of the sample using a lithography tool, and the second set of measurement target features further includes one or more fourth features formed by exposing a fourth exposure field on the second layer of the sample using a lithography tool, wherein the first exposure field and the second exposure field are overlapping exposure fields that completely overlap in the first and second layers. The first exposure field and the third exposure field are partially overlapping fields that partially overlap in the first layer, and the second exposure field and the fourth exposure field are partially overlapping fields that partially overlap in the second layer. One or more manufacturing errors during the fabrication of a measurement target are identified based on at least the first and second measurement datasets, by specifying the overlay error spanning the first and second layers based on the relative position and / or relative dimensions of the first feature in the first set relative to the second feature in the first set, and the relative position and / or relative dimensions of the third feature in the second set relative to the fourth feature in the second set; by specifying the inter-field error in the first layer based on the relative position and / or relative dimensions of the first feature in the first set relative to the third feature in the second set; and by specifying the inter-field error in the second layer based on the relative position and / or relative dimensions of the second feature in the first set relative to the fourth feature in the second set. A measurement system, which is a program instruction that executes a measurement system.

2. A measurement system according to claim 1, The program instruction is directed to one or more processors, The field error spanning the first and second layers is determined by at least one of the relative position and / or relative dimensions of the first feature of the first set with respect to the fourth feature of the second set, and the relative position and / or relative dimensions of the second feature of the first set with respect to the third feature of the second set, These are program instructions that execute the program. Measurement system.

3. A measurement system according to claim 1, The one or more manufacturing errors include errors related to the lithography tool, Measurement system.

4. A measurement system according to claim 3, The one or more manufacturing errors include at least one of field scaling errors, inter-field alignment errors, sample / mask alignment errors, or overlay errors. Measurement system.

5. A measurement system according to claim 1, The one or more manufacturing errors include errors related to the sample, Measurement system.

6. A measurement system according to claim 5, The one or more manufacturing errors include errors caused by at least one of stress on the field sample or defects in the sample. Measurement system.

7. A measurement system according to claim 1, The aforementioned measurement tool includes an image-based measurement tool. Measurement system.

8. A measurement system according to claim 7, The first and second sets of measurement target features include the measurement target, Measurement system.

9. A measurement system according to claim 8, The measurement target includes at least one of an imaging measurement (AIM) target, an AIM chip target, a multilayer AIM chip target, a nested box target, or a "ruler" target. Measurement system.

10. A measurement system according to claim 8, The first and second sets of measurement target features include a scatterometry measurement target, Measurement system.

11. A measurement system according to claim 10, The measurement tool includes a scantometry-based measurement tool. Measurement system.

12. A measurement system according to claim 8, The measurement target is rotationally symmetrical, being symmetrical in at least one of 90 degrees or 180 degrees. Measurement system.

13. A measurement system according to claim 8, The measurement target is mirror-symmetric with respect to at least one axis. Measurement system.

14. A measurement system according to claim 1, The first and second sets of measurement target features include two or more measurement targets, Measurement system.

15. A measurement method, The step is to generate a first set of measurement datasets relating to a first set of measurement target features on a sample, wherein the first set of measurement target features includes one or more first features formed by exposing a first exposure field on a first layer of the sample using a lithography tool, and one or more second features formed by exposing a second exposure field on a second layer of the sample that is different from the first layer using the lithography tool, wherein the first exposure field and the second exposure field are overlapping exposure fields that completely overlap in the first and second layers. The step is to generate a second set of measurement datasets relating to a second set of measurement target features on the sample, wherein the second set of measurement target features includes one or more third features formed by exposing a third exposure field on the first layer of the sample using the lithography tool, and the second set of measurement target features further includes one or more fourth features formed by exposing a fourth exposure field on the second layer of the sample, and the first exposure field and the second exposure field are overlapping exposure fields that completely overlap in the first and second layers. The first exposure field and the third exposure field are partially overlapping fields that partially overlap in the first layer, and the second exposure field and the fourth exposure field are partially overlapping fields that partially overlap in the second layer. One or more manufacturing errors during the fabrication of a measurement target are identified based on at least the first and second measurement datasets, by determining the overlay error spanning the first and second layers based on the relative position and / or relative dimensions of the first feature in the first set relative to the second feature in the first set, and the relative position and / or relative dimensions of the third feature in the second set relative to the fourth feature in the second set; by determining the inter-field error in the first layer based on the relative position and / or relative dimensions of the first feature in the first set relative to the third feature in the second set; and by determining the inter-field error in the second layer based on the relative position and / or relative dimensions of the second feature in the first set relative to the fourth feature in the second set. Measurement method.

16. In the measurement method described in claim 15, further, The field error spanning the first and second layers is determined by at least one of the relative position and / or relative dimensions of the first feature of the first set with respect to the fourth feature of the second set, and the relative position and / or relative dimensions of the second feature of the first set with respect to the third feature of the second set. Measurement method.

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