Optical device and method of optical device metrology

Abstract

Embodiments of the present disclosure relate to optical devices having one or more metrology features and methods of optical device metrology to provide metrology tool position identification with negligible impact on optical performance of the optical device. The optical device includes one or more target features. The target features described herein provide metrology tool position identification with negligible impact on optical performance of the optical device. In a metrology process, the target features allow the metrology tool to determine one or more positions of the optical device having a surface area of a macro-scale. The target features correspond to one or more structures merged together, one or more structures merged together surrounded by one or more structures that have been removed, or one or more structures that have been removed having one or more contours defined by structures adjacent to the target features.

Description

background Technical Field

[0002] The embodiments of this disclosure generally relate to optical devices and methods for measuring optical devices. More specifically, the embodiments of this disclosure relate to optical devices having one or more metrological features and methods for measuring optical devices that provide position identification of metrological tools while having negligible impact on the optical performance of the optical device. Background Technology

[0004] Optical devices can be used to manipulate the propagation of light. One example of an optical device is a planar optical device, such as a metasurface. Another example is a waveguide combiner, such as an augmented reality waveguide combiner. Optical devices in the visible and near-infrared spectroscopy may require structures mounted on substrate surfaces with macroscopic dimensions, such as nanostructures. The optical performance of an optical device depends on the properties of the nanostructure. These properties include the size of the nanostructure and its position relative to other nanostructures.

[0005] As an emerging technology, processing substrates to form optical devices is both complex and challenging. Metrology is required to verify the dimensions of nanostructures to ensure they are within acceptable tolerances. Accordingly, what is needed in the art are optical devices with one or more metrological features and metrological methods that provide positional identification of metrological tools while having negligible impact on the optical performance of the device. Summary of the Invention

[0006] Embodiments of this disclosure generally relate to optical devices and methods for measuring optical devices. In one embodiment, the optical device includes: a substrate and a plurality of structures disposed on the surface of the substrate of the optical device. The plurality of structures include a critical size of less than one micrometer. The plurality of structures include one or more target features corresponding to one or more structures combined together. The ratio of one or more target features to the plurality of structures is between about 1:100,000 and about 1:1,000,000,000.

[0007] In another embodiment, the optical device includes a substrate and a plurality of structures disposed on the surface of the substrate. The plurality of structures include a critical dimension of less than one micrometer. The plurality of structures include one or more target features. The ratio of the one or more target features to the plurality of structures is between about 1:100,000 and about 1:1,000,000,000. The one or more target features can be read by a metrological tool, and the one or more target features include at least one or more structures merged together, one or more merged structures surrounded by one or more removed structures, or one or more removed structures having one or more contours defined by structures adjacent to the target features.

[0008] In another embodiment, the method includes the step of guiding the measuring area of ​​a metrological tool over an approximate first position on the surface of a substrate of an optical device. The method further includes the step of identifying the precise location of a first target feature of the optical device, the optical device including a plurality of structures disposed on the surface. The plurality of structures includes one or more target features, wherein the one or more target features can be read by the metrological tool, and the one or more target features include at least one of the following: one or more structures merged together, one or more merged structures surrounded by one or more removed structures, or one or more removed structures having one or more contours defined by structures adjacent to the target feature. The method further includes the step of determining one or more of the following for at least one of the plurality of structures based on the precise location within the measuring area: critical dimension, gap, pitch, and perimeter distance. The method further includes repeating the following steps at one or more subsequent locations: guiding the measuring tool to measure the area, identifying target features, and determining one or more of the following for at least one of the plurality of structures: critical size, gap, pitch, and perimeter distance. Attached Figure Description

[0009] To gain a more detailed understanding of the features described above in this disclosure, a more specific description of the disclosure, which has been briefly summarized above, can be obtained by referring to embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only typical embodiments of this disclosure and should not be considered as limiting the scope of this disclosure, as other equivalent embodiments are permissible.

[0010] Figure 1A , Figure 1C and Figure 1E This is a schematic top view of an optical device having one or more target features according to the embodiments described herein.

[0011] Figure 1B , Figure 1D and Figure 1F This is a schematic cross-sectional view of an optical device having one or more target features according to the embodiments described herein.

[0012] Figure 2 This is a flowchart of a method for measuring optical devices according to the embodiments described herein.

[0013] For ease of understanding, the same reference numerals have been used as much as possible to denote the same elements common to multiple figures. Elements disclosed in one embodiment are intended to be useful in other embodiments without specific description. Detailed Implementation

[0014] Embodiments of this disclosure generally relate to optical devices and methods for measuring optical devices. The metrological features of the optical devices described herein provide location identification for metrological tools with negligible impact on the optical performance of the optical device. These metrological features allow metrological tools to determine one or more locations of a portion of an optical device having a macroscopic surface area.

[0015] Figure 1A This is a schematic top view of an optical device 100a having one or more target features 114 according to the embodiments described herein, and Figure 1B This is a schematic cross-sectional view of an optical device 100a having one or more target features 114 according to the embodiments described herein. Figure 1C This is a schematic top view of an optical device 100b having one or more target features 114 according to the embodiments described herein, and Figure 1D This is a schematic cross-sectional view of an optical device 100b having one or more target features 114 according to the embodiments described herein. Figure 1E This is a schematic top view of an optical device 100c having one or more target features 114 according to the embodiments described herein, and Figure 1F This is a schematic cross-sectional view of an optical device 100c having one or more target features 114 according to the embodiments described herein.

[0016] The embodiments described herein provide optical devices 100a, 100b, and 100c, which include a structure 102 disposed on a surface 103 of a substrate 101. In some embodiments that can be combined with other embodiments described herein, optical devices 100a, 100b, and 100c are planar optical devices, such as metasurfaces. In other embodiments that can be combined with other embodiments described herein, optical devices 100a, 100b, and 100c are waveguide synthesizers, such as augmented reality waveguide synthesizers. In one embodiment that can be combined with other embodiments described herein, the surface area 109 of the substrate 101 is approximately 70 cm². 2 Approximately 800cm 2 The surface 103 of the substrate 101 includes structures 102 disposed on the surface 103, such as nanostructures, having a size less than one micrometer, for example, a nanometer-sized size. The structure 102 has a critical dimension 106, such as one of the following: the width or diameter of the structure 102, the pitch of the structure 102, or the gap between the structures 102. In one embodiment that can be combined with other embodiments described herein, the critical dimension 106 is less than 1 micrometer (μm) and corresponds to the width or diameter of the structure 102, depending on the cross-section of the structure 102. In one embodiment that can be combined with other embodiments described herein, the critical dimension 106 is from about 100 nanometers (nm) to about 1000 nm. Although... Figures 1A to 1F Structure 102 is depicted as having a square or rectangular cross-section. The cross-section of structure 102 may have other shapes, including but not limited to: circular, triangular, elliptical, regular polygonal, irregular polygonal, and / or irregularly shaped cross-sections. In some embodiments that can be combined with other embodiments described herein, the cross-section of structure 102 on a single optical device 100a, 100b, 100c has different shapes.

[0017] Each of the optical devices 100a, 100b, and 100c includes a critical dimension 102 in its structure 102. In some embodiments that can be combined with other embodiments described herein, at least one of the critical dimensions 106 of structure 102 may differ from at least one of the critical dimensions 106 of one or more other structures 102. In some embodiments that can be combined with other embodiments described herein, gaps 108 are provided between each structure in structure 102. In some embodiments that can be combined with other embodiments described herein, one or more of the gaps 108 surrounding structure 102 differ from one or more other gaps 108 surrounding another structure 102. In some embodiments that can be combined with other embodiments described herein, structure 102 may be arranged in one or more arrays 104. One or more arrays 104 may be arranged non-periodically. In some embodiments that can be combined with other embodiments described herein, structure 102 may be arranged in two or more arrays 104. In embodiments that can be combined with other embodiments described herein, each structure in structure 102 may have a pitch 110, i.e., the distance between the leading edges of adjacent structures 102. In one embodiment that can be combined with other embodiments described herein, the pitch 110 in the X direction is different from the pitch 110 in the Y direction. In another embodiment that can be combined with other embodiments described herein, one or more pitches 110 in the X direction are different from one or more other pitches 110 in the X direction, and / or one or more pitches 110 in the Y direction are different from one or more other pitches 110 in the Y direction. In some embodiments that can be combined with other embodiments described herein, a structure 102 adjacent to one edge of the edge 111 of surface 103 may have a peripheral distance 112, i.e., the distance from structure 102 to one edge of the edge 111 immediately adjacent to that structure 102. In one embodiment that can be combined with other embodiments described herein, at least one of the peripheral distances 112 may be different from the other peripheral distances 112.

[0018] Multiple structures 102 include one or more target features 114a, 114b, ... 114n (collectively referred to herein as "target features 114"). In one embodiment that can be combined with other embodiments described herein, target feature 114 corresponds to one or more structures 102 merged together. In another embodiment that can be combined with other embodiments described herein, target feature 114 corresponds to one or more merged structures 102 surrounded by one or more removed structures 102. In yet another embodiment that can be combined with other embodiments described herein, target feature 114 corresponds to one or more removed structures 102 having one or more contours defined by structures 102 adjacent to target feature 114. The target feature 114 described herein provides position identification of metrological tools and has a negligible impact on the optical performance of optical devices 100a, 100b, and 100c. For example, optical devices 100a, 100b and 100c have a ratio of approximately 1:100,000 to approximately 1:1,000,000,000 of a combined structure 102, a removed structure 102, or a combination of both to the total structure 102.

[0019] In metrological processes (such as method 200 described herein), target feature 114 allows a metrological tool to determine one or more locations 116 of a surface 103 (e.g., a surface 103 having a macroscopic surface area 109). From one or more locations 116, the metrological tool (such as any electron beam-based metrological tool, including but not limited to scanning electron microscopy (SEM), critical-size scanning electron microscopy (CDSEM), or transmission electron microscopy (TEM)) can measure one or more of the following: critical size 106, gap 108, pitch 110, peripheral distance 112, and other dimensions within the measurement area 118 of the metrological tool. In one embodiment, which can be combined with other embodiments described herein, the measurement area 118 is less than about 40 micrometers (μm). One or more target features 114 can be read by the metrological tool. One or more target features 114 allow measurement of one or more of the following by a metrological tool: the critical dimension 106 of each of one or more structures 102 set on surface 103 and having macroscopic dimensions, the gap 108, the pitch 110, the perimeter distance 112, and other dimensions.

[0020] like Figure 1A and 1B As shown, target feature 114 may correspond to one or more structures 102 combined together. This can be combined with other embodiments described herein. Figure 1A and Figure 1BIn the implementation of the method, the target feature 114 includes, but is not limited to, cross (e.g., Figure 1A and Figure 1B (as shown in the image), rectangles, squares, circles, semicircles, triangles, and / or other patterns that can be read by metrology tools (such as any electron beam-based metrology tool, including but not limited to SEM, CDSEM, or TEM). Figure 1C and Figure 1D As shown, target feature 114 may correspond to one or more structures 102 that have been removed. This can be combined with other embodiments described herein. Figure 1C and Figure 1D In this embodiment, the target feature 114 has one or more contours 117a, 117b, ... 117n (collectively referred to herein as "contour 117"), which are defined by the structure 102 of the optical device 100b adjacent to the removed structure 102. Contour 117 includes, but is not limited to, intersections (such as... Figure 1C and Figure 1D (as shown in the image), rectangles, squares, circles, semicircles, triangles, and / or other patterns that can be read by metrology tools (such as any electron beam-based metrology tool, including but not limited to SEM, CDSEM, or TEM). Figure 1E and Figure 1F As shown, target feature 114 may correspond to one or more structures 102 that are merged together and surrounded by one or more removed structures 102. This can be combined with other embodiments described herein. Figure 1E and Figure 1F In the implementation of the method, the target feature 114 includes, but is not limited to, intersections (such as... Figure 1E and Figure 1F (as shown in the figure), rectangles, squares, circles, semicircles, triangles, and / or other patterns that can be read by metrology tools (such as any electron beam-based metrology tool, including but not limited to SEM, CDSEM, or TEM).

[0021] In one embodiment that can be combined with other embodiments described herein, structure 102 is formed of a substrate material. In another embodiment that can be combined with other embodiments described herein, structure 102 includes one or more structural materials. In one embodiment that can be combined with other embodiments described herein, one or more target features 114 are formed of a substrate material. In another embodiment that can be combined with other embodiments described herein, target feature 114 includes one or more structural materials. In another embodiment that can be combined with other embodiments described herein, structure 102 and target feature 114 include the same material. In yet another embodiment that can be combined with other embodiments described herein, structure 102 and target feature 114 include different materials.

[0022] The substrate 101 may also be selected to transmit a suitable amount of light of a desired wavelength or wavelength range, such as one or more wavelengths from about 100 to about 3000 nanometers. Non-limitingly, in some embodiments, the substrate 101 is configured such that it transmits about 50% to about 100% of the infrared to ultraviolet region of the spectrum greater than or equal to the transmission rate. The substrate 101 may be formed of any suitable material, provided that it can sufficiently transmit light in the desired wavelength or wavelength range and can serve as adequate support for the optical devices 100a, 100b, 100c described herein. In some embodiments that can be combined with other embodiments described herein, the material of the substrate 101 has a relatively low refractive index compared to the refractive index of the structural materials of the plurality of structures 102. Substrate selection may include substrates of any suitable material, including but not limited to amorphous dielectrics, non-amorphous dielectrics, crystalline dielectrics, silicon oxide, polymers, and combinations thereof. In some embodiments that can be combined with other embodiments described herein, the substrate 101 comprises a transparent material. In one embodiment that can be combined with other embodiments described herein, substrate 101 is transparent and has an absorption coefficient of less than 0.001. Suitable examples may include oxides, sulfides, phosphides, tellurides, or combinations thereof. In one example, substrate 101 comprises silicon (Si), silicon dioxide (SiO2), silicon nitride (SiN), fused silica, quartz, silicon carbide (SiC), germanium (Ge), silicon germanium (SiGe), indium phosphide (InP), gallium arsenide (GaAs), gallium nitride (GaN), sapphire, a high-refractive-index transparent material (such as high-refractive-index glass), or a combination thereof.

[0023] In one embodiment that can be combined with other embodiments described herein, the structural material of structure 102 and / or target feature 114 includes a non-conductive material, such as a dielectric material. The dielectric material may include amorphous dielectrics, non-amorphous dielectrics, and crystalline dielectrics. Examples of dielectric materials include, but are not limited to, silicon-containing materials, such as Si, silicon nitride (Si3N4), silicon oxynitride, and silicon dioxide. Silicon may be crystalline silicon, polycrystalline silicon, and / or amorphous silicon (a-Si). In another embodiment that can be combined with other embodiments described herein, the structural material of structure 102 and / or target feature 114 includes a metal-containing dielectric material. Examples of metal-containing dielectric materials include, but are not limited to, materials containing titanium dioxide (TiO2), zinc oxide (ZnO), tin dioxide (SnO2), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), cadmium stannate (Cd2SnO4), cadmium stannate (tin oxide) (CTO), zinc stannate (SnZnO3), and niobium oxide (Nb2O5). In yet another embodiment, which can be combined with other embodiments described herein, the structural material of the structure and / or target feature 114 comprises a nanoimprint resist material. Examples of nanoimprint resist materials include, but are not limited to, at least one of the following: spin-coated glass (SOG), flowable SOG, organic, inorganic, and hybrid (organic and inorganic) nanoimprintable materials, which may contain at least one of the following: silicon carbide (SiOC), titanium dioxide (TiO2), silicon dioxide (SiO2), vanadium oxide (IV) (VO2) x Materials of aluminum oxide (Al2O3), indium tin oxide (ITO), zinc oxide (ZnO), tantalum pentoxide (Ta2O5), silicon nitride (Si3N4), titanium nitride (TiN), and zirconium dioxide (ZrO2), or combinations thereof.

[0024] In one embodiment that can be combined with other embodiments described herein, structure 102 and target feature 114 can be formed by one of the following: ion beam etching, reactive ion etching, electron beam etching, wet etching, nanoimprint lithography (NIL), and combinations thereof. In another embodiment that can be combined with other embodiments described herein, a photoresist is disposed on one of the structural material layer and the surface 103 of the substrate 101. In another embodiment that can be combined with other embodiments described herein, the NIL process is used to directly pattern the structural material layer. In one embodiment that can be combined with other embodiments described herein, the photoresist is exposed and developed in a photolithography process to expose an unmasked portion of a hard mask disposed between one of the structural material layer and the surface 103 and the photoresist. In another embodiment that can be combined with other embodiments described herein, the photoresist is imprinted in a NIL process to expose an unmasked portion of a hard mask disposed between one of the structural material layer and the surface 103 and the photoresist. The unmasked portion of the hard mask is etched to expose one of the structural material layer and the surface 103. The exposed structural material layer or surface 103 is etched to form structure 102 and target feature 114. In embodiments that can be combined with other embodiments described herein, the exposed structural material layer or surface 103 is etched by ion beam etching or electron beam etching. In some embodiments that can be combined with other embodiments described herein, a hard mask is removed after etching the exposed structural material layer or surface 103.

[0025] Figure 2 This is a flowchart of a method 200 for metrology of an optical device. Method 200 provides the determination of one or more of the following: critical dimensions 106, gaps 108, pitches 110, peripheral distances 112, and other dimensions for each of one or more structures 102 of the optical devices 100a, 100b, and 100c. Method 200 utilizes a metrology tool (such as a CDSEM) based on instructions associated with corresponding features 114 as described herein, which is operable to: guide a measurement area 118 (e.g., imaging area) to one or more locations 116, read one or more target features 114, and measure one or more of the following: critical dimensions 106, gaps 108, pitches 110, peripheral distances 112, and other dimensions for each of one or more structures 102.

[0026] At operation 201, the measuring tool guides the measuring area 118 to a first position 116a of one or more positions 116 within the approximate area. At operation 202, once the measuring tool has guided the measuring area 118 to the approximate area of ​​the first position 116a, the measuring tool identifies the precise location of the first target feature 114a of the optical devices 100a, 100b, 100c. In one embodiment that can be combined with other embodiments described herein, the precise location of the first target feature 114a is within approximately 40 μm of the first position 116a. In one embodiment that can be combined with other embodiments described herein, the measuring tool uses image recognition (IR) software to identify the precise location of the first target feature 114a of the optical devices 100a, 100b, 100c. At operation 203, based on instructions associated with the first position 116a, the measuring tool measures one or more of the following at a specific location relative to the first target feature 114a and within the measuring area 118 of the first position 116a: critical dimensions 106, gaps 108, pitches 110, perimeter distances 112, and other dimensions of one or more structures 102. In one embodiment that can be combined with other embodiments described herein, as the measuring tool moves to the precise position of the first target feature 114a relative to the measuring area 118, the measuring tool can operate to store instructions to determine one or more of the following: critical dimensions 106, gaps 108, pitches 110, perimeter distances 112, and other dimensions of one or more structures 102.

[0027] At optional operation 204, operations 201 and 202 are repeated for subsequent target features 114b and 114n. After locating the subsequent target features 114b and 114n, operations 201, 202, and 203 may be repeated until the desired measurement result of one or more of the following is obtained by the metrology tool: critical dimension 106, gap 108, pitch 110, perimeter distance 112, and other dimensions of one or more structures 102. In one embodiment that can be combined with other embodiments described herein, when the metrology tool is moved to the precise position of the subsequent target feature 114b relative to the measurement area 118, the metrology tool can be operated to store instructions to determine one or more of the following: critical dimension 106, gap 108, pitch 110, perimeter distance 112, and other dimensions of one or more structures 102. In another embodiment that can be combined with other embodiments described herein, when a subsequent target feature 114n is read or identified by a measuring tool, the measuring tool can be operated to store instructions to determine one or more of the following: critical dimensions 106, gaps 108, pitches 110, peripheral distances 112, and other dimensions of one or more structures 102.

[0028] In summary, this invention provides optical devices 100a, 100b, 100c having one or more target features 114, and methods for metrologically measuring optical devices. The target features 114 described herein provide location identification for metrological tools, while having a negligible impact on the optical performance of optical devices 100a, 100b, 100c. In metrological processes (such as the method 200 described herein), the target features 114 allow metrological tools to determine one or more locations 116 of a surface 103 having a macroscopic surface area 109. At one or more locations 116, metrological tools (such as CDSEMs) are able to reliably and accurately measure one or more of the following: critical dimensions 106, gaps 108, pitches 110, peripheral distances 112, and other dimensions of one or more structures 102 disposed on the surface 103.

[0029] While the embodiments described above relate to this disclosure, other and further embodiments of this disclosure may be designed without departing from the basic scope of this disclosure, and the scope of this disclosure is determined by the appended claims.

Claims

1. An optical device, comprising: a substrate; and a plurality of structures disposed on a surface of the substrate of the optical device, the plurality of structures having a critical dimension of less than one micron, the plurality of structures including one or more target features corresponding to one or more structures merged together, wherein a ratio of one or more target features to the plurality of structures is between 1: 100,000 and 1: 1,000,000,000, and wherein the one or more target features are readable by a metrology tool.

2. The optical device of claim 1, wherein the metrology tool includes a scanning electron microscope (SEM), a critical dimension scanning electron microscope (CDSEM), or a transmission electron microscope (TEM).

3. The optical device of claim 2, wherein the structures merged together include crosses, rectangles, squares, circles, semicircles, triangles, and / or other patterns that are readable by the metrology tool.

4. The optical device of claim 2, wherein the one or more target features correspond to one or more structures of the plurality of structures merged together surrounded by one or more structures of the plurality of structures that have been removed.

5. The optical device of claim 2, wherein the one or more target features correspond to one or more structures of the plurality of structures that have been removed having one or more contours defined by structures adjacent to the target features.

6. The optical device of claim 5, wherein the one or more contours include crosses, rectangles, squares, circles, semicircles, triangles, and / or other patterns that are readable by the metrology tool.

7. The optical device of claim 1, wherein the plurality of structures include structures including: a width or diameter corresponding to a critical dimension of the plurality of structures; a gap between each of the structures; and a pitch corresponding to a distance between leading edges of adjacent structures of the plurality of structures.

8. The optical device of claim 7, wherein the plurality of structures are arranged in two or more arrays.

9. The optical device of claim 8, wherein at least one of the critical dimension or the pitch of the plurality of structures of a first array is different than the critical dimension or the pitch of the plurality of structures of a second array.

10. The optical device of claim 7, wherein the plurality of structures are arranged in one or more arrays, and the one or more arrays are arranged aperiodically.

11. An optical device, comprising: a substrate; and substrate; a plurality of structures disposed on a surface of the substrate of the optical device, the plurality of structures having a critical dimension of less than one micron, the plurality of structures including one or more target features corresponding to one or more structures merged together, wherein a ratio of one or more target features to the plurality of structures is between 1: 100,000 and 1: 1,000,000,000, and wherein the one or more target features are readable by a metrology tool. a plurality of structures disposed on a surface of a substrate of the optical device, the plurality of structures having a critical dimension of less than one micron, the plurality of structures including one or more target features, wherein a ratio of one or more target features to the plurality of structures is between 1 : 100,000 and 1 : 1,000,000,000, the one or more target features are readable by a metrology tool, and the one or more target features include at least one of: one or more structures merged together; one or more structures merged together surrounded by one or more structures removed; or one or more structures removed having one or more contours defined by structures adjacent to the target features.

12. A method for optical device metrology, comprising the steps of: directing a measurement area of a metrology tool to an approximate area of a first location of a surface of a substrate of an optical device; identifying an exact location of a first target feature of the optical device, the optical device including a plurality of structures disposed on the surface, the plurality of structures including one or more target features, wherein the one or more target features are readable by a metrology tool, and the one or more target features include at least one of: one or more structures merged together; one or more structures merged together surrounded by the removed one or more structures; or one or more structures removed having one or more contours defined by structures adjacent to the target features; determining one or more of a critical dimension, a gap, a pitch, and a perimeter distance of at least one structure of the plurality of structures based on the exact location within the measurement area; and repeating the steps of directing the measurement area of the metrology tool, identifying a target feature, and determining one or more of a critical dimension, the gap, the pitch, and the perimeter distance of at least one structure of the plurality of structures within the measurement area at one or more subsequent locations.

13. The method of claim 12, wherein the measurement area is less than 40 micrometers (pm).

14. The method of claim 12, wherein a ratio of one or more target features to the plurality of structures is between 1 : 100,000 and 1 : 1,000,000,000.

15. The method of claim 12, wherein the one or more structures merged together include a cross, a rectangle, a square, a circle, a semicircle, a triangle, and / or other pattern readable by the metrology tool.

16. The method of claim 12, wherein the step of identifying the precise position of the first target feature of the optical device comprises the steps of: identifying the exact location of the first target feature using image recognition (IR) software with the metrology tool.

17. The method of claim 12, wherein the metrology tool includes a scanning electron microscope (SEM), a critical dimension scanning electron microscope (CDSEM), or a transmission electron microscope (TEM).

18. The method of claim 12, wherein the step of determining one or more of a critical dimension of at least one structure of the plurality of structures, the gap, the pitch, and the perimeter distance comprises the steps of: to store instructions with the metrology tool to determine one or more of a critical dimension of at least one structure of the plurality of structures, the gap, the pitch, and the perimeter distance when the precise position of the metrology tool relative to the first target feature is moved to the measurement area.

Images