3d profile measurement using linnike interferometer

Abstract

Systems and methods for generating volumetric data are disclosed. Such systems and methods can include scanning a sample at a plurality of focal planes positioned along a depth direction of the sample. Such systems and methods can include generating, via a detector of a metrology subsystem, a plurality of images of a volumetric field of view of the sample at the plurality of focal planes. Such systems and methods can include aggregating the plurality of images to produce volumetric data for the volumetric field of view of the sample. The metrology subsystem can include a Linker interferometer.

Description

Technical Field

[0001] The present disclosure relates generally to interferometry, and more particularly to interferometry of bond pad shapes and gaps between bonded samples. Background Art

[0002] The ever-increasing demand for the physical density of semiconductor devices has led to a trend toward increasingly complex three-dimensional integrated circuit (3DIC) designs. The trend includes: optimizing processes for dedicated functions (e.g., adapting to certain device types, such as 3D NAND devices, complementary metal oxide semiconductor image sensor (CIS) devices, logic gates (e.g., AND gates), etc.); manufacturing device types on different samples; and then combining the samples to provide a single (3D bonded) structure (e.g., via wafer-to-wafer (W2W) bonding, die-to-die (D2D) bonding, die-to-wafer (D2W) bonding, etc.). For example, this combination may be temporary and / or permanent. Furthermore, this combination may be collective and / or direct. For example, collective may mean that multiple coupled dies are collectively D2W (Co-D2W) bonded in a single placement operation and direct may mean that individual dies are sequentially taken and placed.

[0003] One approach for achieving 3D IC design is to fabricate structures on two separate samples and bond them together with structures (interconnects, devices) near the interface. This technique can facilitate complex structure integration because the two samples can be fabricated separately and bonded in a subsequent process. This trend is also driven by the desire to overcome communication bottlenecks between different areas of the sample and between different functions by creating tight interconnects between the bonded samples.

[0004] However, defects can cause voids between the bonding surfaces. Defects can include, for example, undesired bumps, ridges, foreign particles, etc. For example, a particle of 1 micron or less can cause a void of tens of microns in size.

[0005] Some 3D IC methods place stringent requirements on the surfaces of the samples to be bonded and require tight bonding specifications to support tight interconnect density, small features with tight overlay alignment tolerances, etc. As part of the bonding process, the surfaces to be bonded may have a surface shape that is concave to allow a gap to temporarily form between the surfaces. This gap may shrink until the surfaces are bonded via the bonding process using heat and pressure. Typically, the pad shape is characterized prior to bonding by using an atomic force microscope (AFM). Summary of the invention

[0006] According to one or more embodiments of the present disclosure, a metrology system is disclosed. In one illustrative embodiment, the metrology system includes a metrology subsystem. In one illustrative embodiment, the metrology subsystem includes a detector configured for multi-pixel imaging. In one illustrative embodiment, the metrology subsystem includes an illumination source configured to generate an illumination beam. In one illustrative embodiment, the metrology subsystem includes a beam splitter configured to split the illumination beam into a measurement beam propagating in a measurement arm and a reference beam propagating in a reference arm. In one illustrative embodiment, the metrology subsystem includes a measurement objective configured to direct the measurement beam to a sample. In one illustrative embodiment, the metrology subsystem includes one or more illumination optics configured to illuminate a volumetric field of view of the sample with the measurement beam passing through the measurement objective. In one illustrative embodiment, the metrology subsystem includes a reference objective configured to direct the reference beam to a reference sample. In one illustrative embodiment, the metrology subsystem includes a controller communicatively coupled to the detector. In another illustrative embodiment, the controller includes one or more processors and may include a memory. In another illustrative embodiment, the one or more processors are configured to execute a set of program instructions stored on the memory. In another illustrative embodiment, the one or more processors are configured to execute program instructions to cause the one or more processors to receive multiple images from scanning of the sample at multiple focal planes located along the depth direction of the sample to generate the multiple images of the volumetric field of view of the sample at the multiple focal planes via the detector of the metrology subsystem. In another illustrative embodiment, the one or more processors are configured to execute program instructions to cause the one or more processors to aggregate the multiple images to generate volume data of the volumetric field of view of the sample.

[0007] According to one or more embodiments of the present disclosure, a method is disclosed. In one illustrative embodiment, the method may include, but is not limited to, manufacturing a sample according to a manufacturing process, wherein a surface shape of the sample includes a concave shape. In one illustrative embodiment, the method may include generating volume data of the surface shape of the sample using a metrology subsystem including a detector, wherein the metrology subsystem includes a Linnik interferometer, wherein the detector includes a multi-pixel detector. In one illustrative embodiment, the method may include engaging the surface shape of the sample with a second sample configured to engage with the sample. In one illustrative embodiment, the method may include adjusting the manufacturing process based on the volume data.

[0008] According to one or more embodiments of the present disclosure, another method is disclosed. In one illustrative embodiment, the method may include, but is not limited to, scanning the sample at multiple focal planes located along the depth direction of the sample to generate multiple images of a volumetric field of view of the sample at the multiple focal planes via a detector of a metrology subsystem, wherein the detector includes a multi-pixel detector. In one illustrative embodiment, the method may include aggregating the multiple images to generate volume data of the volumetric field of view of the sample.

[0009] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not necessarily limit the invention as claimed.The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the general description serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Those skilled in the art may better appreciate the numerous advantages of the present disclosure by referring to the accompanying drawings.

[0011] Figure 1A is a conceptual diagram illustrating a metrology system according to one or more embodiments of the present disclosure.

[0012] Figure 1B is a conceptual diagram of an image-based metrology subsystem according to one or more embodiments of the present disclosure.

[0013] Figure 1C is a schematic diagram of a metrology subsystem including a Linnik interferometer-based sample positioning subsystem according to one or more embodiments of the present disclosure.

[0014] Figure 1D is a schematic ray diagram illustrating propagation of oblique illumination through a metrology subsystem in accordance with one or more embodiments of the present disclosure.

[0015] Figure 1E is a schematic diagram of a metrology subsystem for imaging a void of a bonded sample according to one or more embodiments of the present disclosure.

[0016] Figure 1F is a schematic diagram of a metrology subsystem for imaging the pad shape of a pre-bonded sample in accordance with one or more embodiments of the present disclosure.

[0017] Figure 1G is a schematic diagram of a metrology subsystem for imaging through silicon vias (TSVs) of a bonded sample according to one or more embodiments of the present disclosure.

[0018] Figure 1H is a schematic diagram of a metrology subsystem for targeted imaging of a sample in accordance with one or more embodiments of the present disclosure.

[0019] Figure 2is a 3D volumetric topological profile of a buried volumetric field of view of a sample reconstructed from interferometric tool data according to one or more embodiments of the present disclosure.

[0020] Figure 3 is a flow chart illustrating steps performed in a method for generating volume data according to one or more embodiments of the present disclosure.

[0021] Figure 4 is a flow chart illustrating steps performed in a method for generating volume data according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0022] Reference will now be made in detail to the disclosed objects illustrated in the accompanying drawings. The present disclosure has been particularly shown and described with respect to certain embodiments and specific features thereof. The embodiments described herein should be considered illustrative rather than restrictive. It should be readily apparent to those skilled in the art that various changes and modifications may be made to the form and details without departing from the spirit and scope of the present disclosure.

[0023] Embodiments of the present disclosure are directed to systems and methods for identifying a volumetric field of view containing voids at the interface of a bonded sample and / or measuring the surface of a pre-bonded sample using a metrology subsystem (e.g., an interferometer, a Linnik interferometer, etc.). Some embodiments of the present disclosure are directed to scanning the interface of a bonded sample by taking multiple images along the depth direction of the bonded sample using a Linnik interferometer suitable for infrared imaging (e.g., but not limited to short-wave infrared (SWIR), near infrared (NIR), etc.) and generating volumetric data based on such images to identify and / or characterize the volumetric field of view of the sample. Some embodiments of the present disclosure are directed to generating volumetric data of the surface shape of a pre-bonded sample using a Linnik interferometer in the visible light spectrum.

[0024] One technique for imaging the buried volumetric field of view in a bonded sample, such as a wafer-to-wafer (W2W) bonded sample, is to use acoustic microscopy via an acoustic microscope. However, the lateral resolution of an acoustic microscope may be limited to about 50 microns or more. Another technique is to use a patterned wafer geometry (PWG) tool, which may also be limited in resolution. An advantage of acoustic microscopy and PWG tools is that such tools are generally well suited for large area inspections, but may have low sensitivity to individual device features and may not be suitable for conclusive inspection of such device features. It should also be noted that the gaps between bonded samples (e.g., caused by surface defects, particles / dust, etc.) may be on the order of tens of microns (or less). It is contemplated herein that such gaps may cause problems (e.g., device / feature failure of a sample, lack of desired interconnects between bonded samples, bonded samples out of specification / tolerance, etc.) due to the characteristic reduced feature sizes and tighter tolerance requirements of 3D ICs. Therefore, it is contemplated herein that the resolution of acoustic microscopy may be insufficient to detect the volumetric field of view of a sample that may cause such problems.

[0025] There can be challenges with metrology based on the surface shape of the pre-bonded sample. In some processes, the surface shape of the wafer, die, etc. may be concave in shape to allow for proper bonding. In this arrangement, the concavity of the pre-bonded sample may be combined to form a gap with a second (different) sample configured to bond with the sample when bonded to the surface shape of the sample. This gap may close / shrink due to heat and pressure during the bonding process.

[0026] As the density of devices and interconnects on a sample increases, the tolerances on the required surface shape of the pre-bonded sample may become tighter. One technique for measuring the surface shape of a pre-bonded sample is to use atomic force microscopy (AFM). AFM is typically high resolution, but slower than other measurement techniques.

[0027] Compared to other techniques (e.g., AFM), embodiments of the present disclosure may be faster, more efficient, and provide a better resolution versus imaging speed tradeoff. For example, even if the resolution of embodiments of the present disclosure is lower than that of an AFM, the tradeoff of having a higher imaging speed and the ability to image at a certain resolution (e.g., a resolution within an acceptable tolerance) may provide a preferred solution. For example, using a Linnik interferometer in the visible light spectrum to image the surface topography of a pre-bonded sample may provide one or more benefits and provide an excellent tradeoff over prior art techniques.

[0028] In an embodiment, the Linnik interferometer allows volumetric data generation (e.g., volumetric profilometry capabilities) to be investigated in as fast as (but not necessarily limited to) 300 milliseconds (per volumetric field of view of a measured sample). In some instances, volumetric data generation may occur in 10 milliseconds or less per volumetric field of view of a measured sample. In some instances, volumetric data generation may be investigated with accuracy / precision / resolution down to sub-micron. This resolution may be suitable for measuring pre-bonded surface shapes and / or voids buried at the interface of a bonded sample.

[0029] Embodiments of the present disclosure are directed to systems and methods for performing metrology on a volumetric field of view using a metrology subsystem that scans in a depth direction and generating volumetric data based on images generated from this scan. It should be noted that the use of an imaging subsystem to capture images of buried targets of a joined sample may be disclosed in U.S. patent application Ser. No. 17 / 069,177, filed on Oct. 13, 2020, entitled “IMAGING SYSTEM FOR BURIED METROLOGY TARGETS” (hereinafter referred to as “U.S. Patent Application Ser. No. 17 / 069,177”), the entire text of which is incorporated herein by reference.

[0030] Benefits of at least some embodiments of the present disclosure may include generating volumetric data, higher resolution, faster imaging time, and / or the like. Imaging time may be defined as the time to obtain a measurement of each volumetric field of view of a sample, including focusing time, time to capture an image, alignment time, and the like. For example, imaging time may be imaging time defined relative to a scanning configuration and / or a move-acquire-measure (MAM) configuration. For example, a time delay integration (TDI) detector in a scanning configuration may be used to obtain an image for generating volumetric data, and imaging time may be the time taken to image multiple points of interest divided by the number of points of interest. For example, for some embodiments, imaging time may be hundreds (e.g., 100, 200) milliseconds or less (e.g., less than 100 milliseconds) per measured volumetric field of view. For example, hundreds of milliseconds per surface shape are distributed over a 40 micron x 40 micron area of ​​a pre-joined sample. In some embodiments, a metrology subsystem may be used to achieve resolutions of 5 microns, 3 microns, down to 1 micron, and / or the like.

[0031] As used throughout this disclosure, the term "sample" or "substrate" generally refers to a substrate. For example, a substrate may be a substrate formed of a semiconductor or non-semiconductor material. In some examples, the substrate is a wafer, a die, and the like. For example, the semiconductor or non-semiconductor material may include, but is not limited to, single crystal silicon, gallium arsenide, and indium phosphide. The sample may include one or more layers. For example, such layers may include, but are not limited to, resists (including photoresists), dielectric materials, conductive materials, and semiconductive materials. Many different types of such layers are known in the art, and the term "sample" used herein is intended to cover samples on which all types of such layers can be formed. One or more layers formed on a sample may be patterned or unpatterned. For example, a sample may include multiple dies, each having repeatable patterned features. The formation and processing of such material layers may ultimately result in a completed device. Many different types of devices may be formed on a sample, and the term "sample" used herein is intended to cover samples on which any type of device known in the art is manufactured. Furthermore, for purposes of this disclosure, the terms "sample" and "wafer" should be interpreted as interchangeable, as a sample may be a wafer and a wafer is at least one example of a sample. A die is another example of a sample.

[0032] Reference Figures 1A to 1F , according to one or more embodiments of the present disclosure, systems and methods for imaging a sample 106 and generating volumetric data are described. In at least some embodiments, the systems and methods can be used to augment existing systems and methods for metrology (e.g., overlay metrology) and / or inspection of a sample.

[0033] Figure 1A Conceptual diagram illustrating a metrology system 100 in accordance with one or more embodiments of the present disclosure. In one embodiment, the metrology system 100 includes a metrology subsystem 102 configured to scan at least one volumetric field of view 104 of a sample 106. For example, the metrology subsystem 102 may generate a plurality of field plane images of the volumetric field of view 104 and / or a plurality of pupil plane images of the buried volumetric field of view 104. For example, 50 or more images, 80 or more images, etc. may be sufficient to generate sufficient volumetric data along a depth direction. In another embodiment, the metrology system 100 includes a metrology subsystem 102 configured to scan at least one surface shape of the sample 106, such as at least one surface shape of the surface 160. In general, the volumetric field of view 104 may be and / or include any area, surface, volume, defect, object, void, and / or the like.

[0034] In an embodiment, the sample 106 may include any type of sample known in the art. For example, the sample 106 may include a bonded sample formed by two substrates bonded together at an interface, wherein the volume field of view 104 is located at or near the interface. In addition, the sample may be formed of any material or combination of materials, including but not limited to semiconductors, metals, polymers, glasses, or crystalline materials. In an embodiment, at least one of the samples includes a wafer (e.g., a semiconductor wafer). For example, the sample 106 may be formed as a bonded wafer sample having two wafers bonded at an interface.

[0035] In an embodiment, the sample 106 is a die-to-wafer (D2W) bonding sample. For example, according to a metrology recipe, the metrology system 100, the metrology subsystem 102, and / or the interferometer can be configured to be used with a die-to-wafer sample (e.g., a die-to-wafer bonding sample, a pre-bonded die configured to be bonded to a wafer, and / or the like).

[0036] In an embodiment, the sample 106 is a die-to-die (D2D) bonding sample.

[0037] In an embodiment, the sample 106 is a wafer-to-wafer (W2W) bonded sample.

[0038] In an embodiment, the sample 106 is a die-to-wafer (D2W) bonding sample.

[0039] The metrology subsystem 102 may include any type of metrology subsystem known in the art suitable for generating one or more images of one or more volumetric fields of view 104 on the sample 106 at any plane (e.g., a focal plane) or combination of planes and measuring one or more parameters of interest associated with the sample 106 based on the one or more images.

[0040] In another embodiment, the metrology system 100 includes a controller 108 communicatively coupled to the metrology subsystem 102. In another embodiment, the controller 108 includes one or more processors 110 configured to execute program instructions stored on a memory 112. The one or more processors 110 of the controller 108 may include any processing element known in the art. In this sense, the one or more processors 110 may include any microprocessor-type device configured to execute algorithms and / or instructions. In addition, the memory 112 may include any storage medium known in the art that is suitable for storing program instructions that can be executed by the associated one or more processors 110. For example, the memory 112 may include a non-transitory memory medium. As additional examples, the memory 112 may include (but is not limited to) a read-only memory (ROM), a random access memory (RAM), a magnetic or optical storage (such as a disk), a tape, a solid-state drive, and the like. It should be further noted that the memory 112 may be housed in a common controller housing with the one or more processors 110.

[0041] In this regard, the one or more processors 110 of the controller 108 may perform any of the various process steps described throughout the present disclosure. For example, the one or more processors 110 of the controller 108 may receive one or more images of the buried volume field of view 104 from the detector 124 and generate one or more metrology measurements of the sample 106 based on the one or more images from the detector 124.

[0042] Figure 1B is a conceptual diagram of an image-based metrology subsystem 102 in accordance with one or more embodiments of the present disclosure in an interferometric configuration that may be used to generate volumetric data of a sample 106 .

[0043] In at least some embodiments, Figure 1B is an example representation of an interferometer including a measurement shunt 146 associated with sample 106 and a reference shunt 148 associated with reference sample 144 used as a reference during interference-based interferometric measurements of sample 106 .

[0044] In embodiments, volume data may be generated in various ways, such as by scanning sample 106 in a depth direction. For example, in embodiments, such scanning of sample 106 may include: moving sample 106 in a depth direction via translation stage 140; moving reference sample 144 via a reference translation stage (not shown) configured to move reference sample 144; adjusting a phase of reference beam 166 of reference branch 148; and / or the like.

[0045] In one embodiment, the metrology subsystem 102 includes at least one detector 124 configured to capture at least a portion of detectable light 122 from the light collection path 120. As used herein, the detectable light 122 includes the portion of illumination directed to the detector 124, including a portion of the illumination beam 116 and any other illumination from any other illumination source. For example, the detectable light 122 may include a measurement beam 168 emitted from the sample 106 and a reference beam 166 emitted from the reference sample 144. The detectable light 122 may include interference of the measurement beam 168 and the reference beam 166. This interference may be imaged by the detector 124 to generally produce an interference pattern and, in the case of at least some embodiments of the present disclosure, to produce volumetric data.

[0046] In one embodiment, the metrology subsystem 102 includes an illumination source 114 configured to generate an illumination beam 116. In an embodiment, the metrology system 100 includes an illumination path 118 (e.g., an illumination subsystem) including one or more components (e.g., an illumination lens 126) for directing the illumination beam 116 to the sample 106.

[0047] In another embodiment, the metrology subsystem 102 includes a light collection path 120 (e.g., an imaging subsystem) that includes one or more components for collecting light from the sample 106. It should be noted that "illumination," "light," "beam," "illumination beam," and the like may be used interchangeably throughout this disclosure.

[0048] In one embodiment, the metrology subsystem 102 includes a reference objective 142 configured to receive a portion of the illumination beam 116 through the beam splitter 136, direct this portion of the illumination beam 116 to a reference sample 144, and collect light reflected from this reference sample 144 (e.g., this reflected light may be referred to as a “reference beam 166” of a reference branch 148). In this regard, the measurement objective 134 and the sample 106 may form a measurement branch 146 of a Linnik interferometer and the reference objective 142 and the reference sample 144 may form a reference branch 148 of the Linnik interferometer, such that interference of the measurement beam 168 from the measurement branch 146 and the reference beam 166 from the reference branch 148 is configured to be imaged by the detector 124.

[0049] It should be understood that the systems and methods disclosed herein may be broadly applicable to a variety of samples such that the illumination beam 116 may have any selected spectrum based on the composition of the sample 106 .

[0050] The illumination source 114 may provide an illumination beam 116 having any selected wavelength or range of wavelengths. It is contemplated herein that the spectrum of the illumination beam 116 may be selected to be transmitted through at least a portion of the sample 106 to reach the buried volume field of view 104 with minimal or at least acceptable absorption. For example, where the sample 106 is formed as two bonded semiconductor substrates, the spectrum of the illumination beam 116 may be selected to include wavelengths within the infrared spectral range. For example, a Linnik interferometer may be suitable for infrared imaging. In another example, where the sample 106 is formed as two bonded semiconductor substrates, the spectrum of the illumination beam 116 may be selected to include wavelengths within the short-wave infrared spectral range.

[0051] In another example, such as when the volumetric field of view 104 of the sample 106 to be imaged is a pre-engaged surface 160 (i.e., non-buried) of the sample 106, the spectrum of the illumination beam 116 may be selected to include wavelengths within the visible spectrum range. For example, in an embodiment, a Linnik interferometer configured for operation within the visible light spectrum range may be used as the metrology subsystem 102.

[0052] In an embodiment, the metrology subsystem 102 is configured to generate images within multiple wavelengths (e.g., illumination spectral ranges, channels, etc.), such that the metrology subsystem 102 comprises a multi-wavelength (MWL) metrology subsystem 102. For example, the illumination beam 116 may include different illumination spectral ranges (i.e., channels) and the beam splitter 136 may be a wavelength filter beam splitter, such that the beam splitter 136 is configured to split the illumination beam 116 into two beams of different illumination spectral ranges. However, in this context, different may mean partially different. For example, for proper functionality in at least some embodiments, there should be at least some overlap between the first and second spectral ranges of light. In this regard, in an embodiment, the first spectral range of light partially overlaps with the second spectral range of light. This MWL configuration / technique may allow for improved volumetric data quality (e.g., improved spatial resolution, improved signal-to-noise ratio (SNR), etc.). For example, the illumination beam 116 may include an illumination spectral range of illumination that partially overlaps with the second illumination spectral range, such that the metrology subsystem 102 comprises a multi-wavelength (MWL) metrology subsystem 102. Furthermore, a beam splitter, such as beam splitter 136, may include a wavelength filter beam splitter such that reference beam 166 includes a first illumination spectral range and measurement beam 168 includes a second illumination spectral range.

[0053] In one embodiment, the illumination path 118 includes one or more illumination lenses 126 for directing the illumination beam 116 from the illumination source 114 to the sample 106. Additionally, the illumination lenses 126 may be arranged to relay one or more field planes or pupil planes to a location within the illumination path 118. The illumination path 118 may further include one or more illumination adjustment components 128 suitable for modifying and / or adjusting the illumination beam 116. The illumination adjustment components 128 may, but are not necessarily, located at the field planes and / or pupil planes in the illumination path 118. For example, the one or more illumination adjustment components 128 may include, but are not limited to, an illumination aperture stop, an illumination field stop, one or more polarizers, one or more compensators, 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, one or more mirrors, one or more lenses, and / or one or more masks.

[0054] For example, in some embodiments, components such as one or more masks can be configured to selectively block portions of illumination beam 116 such that the cross-sectional intensity profile at the pupil plane of illumination path 118 is annular in shape (i.e., annular) and illumination beam 116 is an annular illumination beam. This annular illumination beam can generate one or more annular measurement beam rings from one or more diffraction orders emanating from sample 106. One or more similar masks and / or other components can be used to generate a similar and / or matching annular profile for reference beam 166. It should be noted that in some embodiments, annular illumination beam 116 significantly improves / increases the SNR of measurement beam 168 over the use of a spherical illumination beam. Additionally, annular illumination beam 116 can selectively block / reduce the SNR of measurement beam 168 from top samples (e.g., Figure 1E The undesired specular reflections of the top surface (e.g., back surface) of the first sample 106a) of the annular illumination beam 116 can be further improved than using a spherical illumination beam, which can further improve the SNR of the measurement beam 168 compared to using a spherical illumination beam. Such an improvement can be critical for imaging. It should be noted that in some embodiments, the size of the inner diameter (i.e., inner ring diameter) and the outer diameter (i.e., outer ring diameter) of the annular illumination beam 116, which can correspond to a maximum numerical aperture value (NAmax) and a minimum numerical aperture value (NAmin), respectively, can be optimized for volume data generation. For example, simulated data and / or actual pupil plane image data within various ranges of NAmax and NAmin can be generated at multiple focal planes along the depth direction and used to determine / optimize NAmax and NAmin for volume data generation. For example, NAmax and NAmin can be selected so that the SNR is maximized for a specific application of volume data generation (e.g., specular reflection reduction).

[0055] In one embodiment, the annular profile of the annular illumination beam 116 may be configured (eg, via the measurement objective 134 and / or other components not necessarily shown) to be shifted across the pupil plane so that illumination may be provided from different directions.

[0056] In one embodiment, the measurement beam 168 may be decentered (e.g., angled) such that the measurement beam 168 is angled relative to the depth direction (e.g., Z direction) of the sample 106 (i.e., not parallel to the depth direction). For example, one or more fixed and / or adjustable lenses, reflectors, etc. may be used to set the angle of the measurement beam 168 such that the measurement beam 168 is tilted relative to the sample 106. Furthermore, this configuration may be manifested such that a coherence gate of the measurement beam 168 is aligned with a focal plane such that the coherence gate is scanned along the depth direction at multiple focal planes. Additionally, this tilted / angled configuration may allow for, for example, but not limited to, more information (e.g., angled volume data) and / or improvements in increasing SNR. For example, surfaces of sidewalls of features / interconnects that are parallel to the depth direction are generally easier to image at an angle than straight on from above.

[0057] In one embodiment, the collection path 120 includes one or more collection lenses 130 for directing the detectable light 122 from the sample 106 to the detector 124. In another embodiment, the collection path 120 includes one or more collection light conditioning components 132 suitable for modifying and / or conditioning the detectable light 122. For example, the one or more collection light conditioning components 132 may include, but are not limited to, one or more polarizers, one or more filters, one or more beam splitters, one or more diffusers, one or more apodizers, or one or more beam shapers.

[0058] In one embodiment, the metrology subsystem 102 includes a measurement objective 134 for directing the illumination beam 116 to the sample 106 and / or capturing the measurement beam 168 from the sample 106. For example, Figure 1B , the metrology subsystem 102 may include a common beam splitter 136 for both the illumination path 118 and the collection path 120 to allow the measurement objective 134 to simultaneously direct the illumination beam 116 to the sample 106 and capture the measurement beam 168 from the sample 106. In another embodiment, although not shown, the illumination path 118 and the collection path 120 may include separate lenses for directing the illumination beam 116 to the sample 106 and collecting the measurement beam 168, respectively.

[0059] In an embodiment, the cross-sectional area of ​​the illumination beam 116 directed to the sample 106 (as seen toward the focal plane) is larger than the field of view of the detector 124. Similarly, in an embodiment, the imaging area of ​​the plurality of images is larger than the cross-sectional area of ​​the volumetric field of view 104. In this regard, the volumetric field of view 104 may be completely contained within the cross-sectional area of ​​the measurement beam 168 directed to the sample 106, such that the volumetric field of view 104 is, in a sense, fully illuminated.

[0060] In an embodiment, the detector 124 is a multi-pixel detector (e.g., a camera, a 2D detector, a complementary metal oxide semiconductor (CMOS), etc.). In this regard, the detector 124 may be used to image multiple pixels at a time to more efficiently image a volumetric field of view / area and generate volumetric data. In an embodiment, the detector 124 may be suitable for capturing images of a stationary or moving sample 106. For example, the detector 124 may include, but is not limited to, a photodiode array (PDA), a charge coupled device (CCD), a CMOS device, a time delay integration (TDI) detector, a line scan detector, a photomultiplier tube (PMT), an avalanche photodiode (APD), etc. In another embodiment, the detector 124 may include a spectral detector suitable for identifying the wavelength of radiation emitted from the sample 106 and dispersed onto the sensor using a dispersive element.

[0061] In an embodiment, the sample positioning subsystem 138 is used to obtain multiple images of the volumetric field of view of the sample at different focal planes along the depth direction (eg, Z direction) of the sample 106 .

[0062] In one embodiment, the metrology subsystem 102 includes a sample positioning subsystem 138 configured to adjust the sample 106 and / or the illumination beam 116 before, during, and / or after measurement. Figure 1B The sample positioning subsystem 138 is illustrated to include a translation stage 140 to adjust the position of the sample 106 along any dimension, such as (but not limited to) lateral position within the XY plane, axially along the Z axis (e.g., the optical axis of the measurement objective 134), flipping, tilting, etc. As another example, although not shown, the sample positioning subsystem 138 may include one or more scanning optical elements (e.g., galvanometers, rotatable mirrors, etc.) suitable for scanning the illumination beam 116 across the sample 106 or a portion thereof. Similarly, in one embodiment, the metrology subsystem 102 includes a reference sample 144 (in the example of FIG. 1 ) configured to adjust the position of the sample 106 before, during, and / or after measurement. Figure 1C 144) and / or a reference translation stage (not shown) for directing reference beam 166 (to reference sample 144). Figure 1C A sample positioning subsystem 138 is described that may include focusing capabilities enabled by photodiodes and other components.

[0063] Figure 1C is a schematic diagram of a metrology subsystem 102 including a Linnik interferometer-based sample positioning subsystem 138 according to one or more embodiments of the present disclosure. It should be noted that Figure 1C Included are components (eg, photodiode 150, second illumination source 114') that allow for focusing operations that utilize sample positioning data in at least some embodiments. The sample positioning data may be used to bring the sample 106 into focus.

[0064] In one embodiment, the sample positioning subsystem 138 includes one or more components for detecting and / or monitoring the position of the sample 106, the volumetric field of view 104, the surface 160, or any selected layer within the sample 106 along the optical axis of the measurement objective 134. In this regard, the sample positioning subsystem 138 can enable accurate alignment of the volumetric field of view 104 within the metrology subsystem 102. It is contemplated herein that accurate alignment of the volumetric field of view 104 within the metrology system 100 can provide a number of benefits. For example, accurate alignment of the volumetric field of view 104 can facilitate accurate control of the spatial and angular profile of the illumination beam 116 from the illumination source 114 on the volumetric field of view 104 by using an adapted illumination field stop and / or pupil stop, as discussed throughout this disclosure. As another example, accurate alignment of the volumetric field of view 104 can facilitate accurate alignment of the volumetric field of view 104 with the detector 124 to provide a quality image of a selected plane, such as a field plane or a pupil plane.

[0065] The sample positioning subsystem 138 can detect and / or monitor the axial position of the sample 106 or any portion thereof using various techniques. In one embodiment, the sample positioning subsystem 138 includes a Linnik interferometer for determining and / or monitoring the position of the volumetric field of view 104 along the optical axis of the measurement objective 134. For example, the Linnik interferometer can be configured to operate with a spectrum of the illumination beam 116 from the illumination source 114 that can be (but not necessarily be) narrow band (e.g., having a bandwidth of about 5 nm or less). For example, the metrology subsystem 102 can include or be an interferometer that includes a photodiode 150 configured to focus the detector 124 of the interferometer.

[0066] In an embodiment, the metrology subsystem 102 includes a modulator 158 configured to modulate the photodiode beam (i.e., light directed to the photodiode 150) (e.g., which may include a secondary illumination beam from the second illumination source 114'). For example, the modulator 158 may include (or be) at least one of the following: a binary phase filter (BPF), a full width at half maximum (FWHM) filter, or an annular mask. In another example, the modulator 158 includes a BPF, a FWHM filter, and an annular mask. For example, the modulator 158 may be configured for a bandwidth of 5 nm.

[0067] It should be noted that the depth direction can be defined as Figure 1C The focal plane may be normal to the Z direction of the sample, normal to the upper surface of the sample, substantially normal (e.g., within 20 degrees) to the upper surface of the sample, etc. Similarly, the focal plane may be normal to Figure 1C The Z direction, normal to the depth direction, parallel to the upper surface of the sample, substantially parallel to the upper surface of the sample, and so on.

[0068] In one embodiment, the metrology subsystem 102 includes a photodiode 150 for generating sample positioning data of an interference pattern associated with interference between a measurement beam 168 of the measurement branch 146 and a reference beam 166 of the reference branch 148 of the Linnik interferometer. Figure 1C , the metrology subsystem 102 includes an additional beam splitter 152 for providing a continuous interference image. In another embodiment, the metrology subsystem 102 may include a translatable mirror (e.g., a slewing mirror, a mirror on the translation stage 140, etc.) for selectively directing light to the photodiode 150 to produce the interference image. For example, the metrology subsystem 102 may direct all light from the beam splitter 136 to the photodiode 150 when adjusting the position of the sample 106 before measurement to maximize the signal available for focus detection and may then direct all light from the beam splitter 136 to the detector 124 for metrology measurement (e.g., capturing one or more sample images) during measurement.

[0069] In one embodiment, the metrology subsystem 102 may include a shutter 172 or other beam deflector for selectively blocking light in the reference branch 148 during metrology measurements. For example, the metrology subsystem 102 may be (or include) a bright field subsystem. For example, the metrology subsystem 102 may be configured to use bright field imaging techniques and other imaging modes (e.g., Linnik interferometry mode) to allow multi-mode imaging.

[0070] It is contemplated herein that the illumination requirements for metrology and sample positioning may be different. Thus, the metrology subsystem 102 may include any combination of illumination sources and optical elements for providing light having selected properties for both metrology and sample positioning measurements. For example, the metrology subsystem 102 may include a beam diffuser or other component suitable for reducing the spatial coherence of light used for sample positioning to mitigate speckle during measurement.

[0071] In one embodiment, Figure 1C , the metrology subsystem 102 includes a common illumination source 114 for generating volume data and for sample positioning. In this configuration, the metrology subsystem 102 may include one or more optical elements, such as, but not limited to, spectral filters, spatial filters, speckle reducers (such as diffusers, etc.), field stops, pupil stops, or polarizers, for modifying the properties of an illumination beam 116 from the common illumination source 114 for sample positioning measurements. These optical elements may be placed at any suitable location, including, but not limited to, an illumination path 118 for modifying light incident on the sample 106 and / or a collection light path 120 for modifying light collected from the sample 106.

[0072] For example, Figure 1CA spectral filter 154 is illustrated in the light collection path 120 for modifying the spectrum of the illumination beam 116 incident on the photodiode 150 during sample positioning measurements. For example, the spectral filter 154 can narrow the bandwidth of the illumination beam 116 used for sample positioning measurements to a selected bandwidth, such as, but not limited to, 10 nm, 5 nm, 2 nm, 1 nm, or any selected bandwidth. In this regard, the illumination beam 116 used during sample positioning measurements can be monochromatic or quasi-monochromatic. It should be understood that although Figure 1C Spectral filter 154 is illustrated as being placed before photodiode 150 , but it should be understood that spectral filter 154 may be placed at any suitable location, including, but not limited to, illumination path 118 .

[0073] Although spectral filter 154 can be used for focusing, in at least some embodiments, the spectral filter can be critical to the imaging itself. In one example, a non-limiting location for the spectral filter is in the light collection path before lens 130, as shown by spectral filter 170. Spectral filter 170 can have the same, similar, or different characteristics as spectral filter 154. For example, spectral filter 170 can be a narrowband spectral filter. It should be noted that in at least some embodiments, if a narrowband spectral filter 170 located before lens 130 is not used, the contrast (e.g., SNR) of the resulting image will be very poor and therefore the axial resolution of such an image will be very poor.

[0074] In another embodiment, the metrology subsystem 102 includes a separate illumination source 114' for sample positioning. It should be noted that US Patent Application 17 / 069,177 generally discloses the use of a separate illumination source 114' and a photodiode 150 for sample positioning.

[0075] For example, Figure 1C As described in , a separate illumination source 114' for sample positioning can be integrated into the sample positioning subsystem 138. For example, the sample positioning subsystem 138 can utilize Figure 1C 1 to direct light from the separate illumination source 114' to the sample 106. By way of another example, although not shown, the illumination path 118 may include a beam splitter 136 or other beam selector for providing selective illumination of the sample 106 from any of the two or more illumination sources. In general, a beam splitter may be configured to split illumination into two or more illumination / paths traveling in two or more directions.

[0076] It is further contemplated herein that the geometry of the buried volume field of view 104 in the sample 106 may present challenges to typical interferometric sample positioning techniques including, but not limited to, Linnik interferometry. For example, light propagation through the sample 106 and reference sample 144 may introduce dispersion or spherical aberration that may negatively impact sample positioning measurements.

[0077] The metrology subsystem 102 may utilize any spatial or angular profile of light in the sample positioning measurement. In one embodiment, the metrology subsystem 102 provides oblique illumination (e.g., annular illumination, dipole illumination, quadrupole illumination, etc.) for sample positioning measurement. For example, the metrology subsystem 102 may include (but does not necessarily include) a central mask (e.g., a numerical aperture) located in the illumination pupil of the illumination path 118 to produce annular illumination with a selected angular range on the sample 106 and the reference sample 144.

[0078] The metrology subsystem 102 may include various other components (eg, lenses, optics, etc.) for directing / shaping illumination, such as components 162a, 162b, 162c, 162d shown in various locations, but are not limited to such locations.

[0079] Figure 1D is a schematic ray diagram illustrating the propagation of oblique illumination through the metrology subsystem 102 according to one or more embodiments of the present disclosure. For example, Figure 1D The illumination beam 116 may be illustrated as propagating from a single point along a circular profile. Furthermore, it should be understood that Figure 1D It is not intended to be a strict ray diagram and the illustration of three rays from pupil plane 156 is provided for illustration only to indicate illumination beam 116 of sample 106 and reference sample 144 across the spatial field of view.

[0080] It is contemplated herein that oblique illumination, and in particular high angle or high numerical aperture (NA) illumination, can facilitate sensitive and accurate sample location measurements using Linnik interferometry. For example, reflections from the top surface of sample 106 and the top surface of reference sample 144 can affect the signal associated with reflections from the volume field of view 104 of samples buried in sample 106. To mitigate this, illumination beam 116 can be designed to have an annular or other high NA profile during sample location measurements to avoid collecting specular reflections from the top surfaces of sample 106 and reference sample 144.

[0081] At least some embodiments of the metrology system 100 may be used in a variety of applications, some non-limiting examples of which are described in Figures 1E to 1H For example, applications may include generating volumetric data of inter-sample gaps, pad shapes, TSVs, targets, and the like.

[0082] Figure 1Eis a schematic diagram of a metrology subsystem 102 having a measurement lens 134 and imaging a gap 104 of joined samples 106a, 106b according to one or more embodiments of the present disclosure. It should be noted that other components of the metrology subsystem 102 are removed for simplicity and clarity.

[0083] In an embodiment, as described throughout, the void 104 may be formed at the interface between two joined samples 106a, 106b. It should be noted that, in general, the sample 106 may include a plurality of layers 164 (e.g., 2 layers, 10 layers, hundreds of layers, etc.). The surface 160 of the sample 106 may be directly and / or indirectly mated. The illumination beam 116 is shown penetrating the first sample 106a to image the void 104.

[0084] As mentioned above, when imaging buried volume field of view 104 , using light configured to image in infrared spectral range 102 and / or shortwave infrared spectral range of light may be advantageous as such light may provide improved imaging of buried portions of sample 106 .

[0085] Figure 1F is a schematic diagram of a metrology subsystem 102 having a measurement objective 134 and imaging a surface 160 shape (e.g., a concave shape of a pad surface) of a pre-bonded sample 106 in accordance with one or more embodiments of the present disclosure. Although shown in a flat configuration, it should be noted that the surface 160 shape may be concave relative to the metrology subsystem 102.

[0086] As mentioned above, when imaging the surface of a sample rather than a buried volume field of view, it may be advantageous to use a metrology subsystem 102 configured to image in any spectral range that meets other needs, since penetration of the sample is not an issue. For example, the metrology subsystem 102 may be configured to image the surface of the sample 106 in the visible light spectral range or any other spectral range.

[0087] Figure 1G 1 is a schematic diagram of a metrology subsystem 102 having a measurement objective 134 and imaging through silicon vias (TSVs) bonding samples 106a, 106b, 106c according to one or more embodiments of the present disclosure. It should be noted that the TSVs may be located within the volume field of view 104. A TSV may be defined as a vertical electrical connection (through hole) that passes completely through a silicon wafer or die.

[0088] Figure 1H 1 is a schematic diagram of a metrology subsystem 102 having a measurement objective 134 and imaging a target of a sample 106 according to one or more embodiments of the present disclosure. It should be noted that the target may be located within the volume field of view 104. For example, the target may be, but is not limited to, a target grating (e.g., an AIM target) in a scribe line of a wafer. For example, the target may be an overlay target.

[0089] Figure 2 is a 3D volumetric topological profile 200 of a buried volumetric field of view 104 of a sample 106 reconstructed from interferometric tool data (e.g., interferogram data, multi-interferogram data, data obtained using the interferograms of the present disclosure, volumetric data, and / or the like) in accordance with one or more embodiments of the present disclosure. It should be noted that while the topological profile 200 may show an advanced imaging metrology (AIM) metrology target for illustrative purposes, other portions / elements / regions may be imaged to obtain volumetric data, such as (but not limited to) voids 104 located at interfaces and / or pre-bond pad surfaces. For example, volumetric data that may be obtained using embodiments of the present disclosure may be similar to Figure 2 In this regard, the topological profile 200 shown may indicate, but is not limited to, the resolution, roughness / variability, and / or 3-dimensional detail that may be obtained from at least one embodiment of the present disclosure.

[0090] Figure 3 is a flow chart illustrating steps performed in method 300 according to one or more embodiments of the present disclosure. For example, controller 108 may be configured to communicatively couple to metrology subsystem 102 of metrology system 100 and may include processor 110 configured to execute instructions to cause one or more processors 110 to perform the steps of method 300 (and any steps, methods, etc. of the present disclosure).

[0091] In step 302 , the sample 106 is scanned at a plurality of focal planes positioned along a depth direction of the sample 106 to generate a plurality of images of the volumetric field of view 104 at the plurality of focal planes via the detector 124 of the metrology subsystem 102 .

[0092] For example, in an embodiment, such scanning of sample 106 may include: moving sample 106 in the Z direction / depth direction via translation stage 140; moving reference sample 144 via a reference translation stage (not shown); adjusting the phase of reference beam 166 of reference branch 148; and / or the like.

[0093] In step 304, the plurality of images are gathered to generate volume data of the volumetric field of view 104 of the sample 106. For example, by generating a plurality of interference pattern data for a plurality of common positions (e.g., pixels) of at least a portion of the plurality of images. Further, for example, each interference pattern data may be an interference pattern corresponding to each position and each position may be a pixel. In this regard, an interference pattern may be generated for each pixel. The volume data may (but not necessarily) be generated based on such a plurality of interference patterns.

[0094] In an optional step, the volume data may be used to construct a height map of the pre-bonded surface 160 of the sample 106 or the buried volume field of view 104 .

[0095] In an optional step, the volume data may be used to construct a volume contour showing different elements in the 3D volume.

[0096] In an optional step, one or more voids 104 are identified based on the volumetric data.

[0097] In an optional step, characteristics of one or more voids 104 are determined based on the volume data. For example, characteristics such as size, thickness, volume, area, width, length, roughness, location, category, and / or any other characteristic may be determined. For example, the category may be a damage or inhibitor category.

[0098] It should be noted that the metrology system 100 may include or may be coupled to a review tool and / or a PWG tool. The PWG tool may be an imaging tool configured to image the entire (i.e., whole) sample 106 at once (e.g., an interferometry-based tool, but with a significantly larger field of view to image the entire wafer). The review tool may be, for example, an acoustic microscope.

[0099] In an optional step, points of interest across the sample 106 (and / or buried in the sample 106) are identified using at least one of a review tool or a PWG tool. For example, at least a portion of the buried volume field of view 104 may be located at a point of interest. However, not all points of interest will necessarily cause problems, they may simply be flagged as areas that require further review, similar to false positives. Points of interest may be identified using such tools (e.g., review tools, PWG tools) by such tools imaging anomalies or potential anomalies. An anomaly may be any measurement that is unexpected, undesirable, and / or above a threshold. For example, an anomaly may be an unexpected value on an image, a height discontinuity, etc., which may be a particle / void / defect. Such tools may be used for further review at a resolution lower than the metrology subsystem 102 described throughout the present disclosure and requiring flagging of such anomalies.

[0100] It should be noted that the scanning of the sample 106 and / or receiving multiple images step (i.e., step 302), etc. can be based on (e.g., informed by) the above-mentioned point of interest. For example, the receiving multiple images step can be based on the point of interest. For example, in a sense, the point of interest can be the volumetric field of view 104 of the sample 106 to be further examined.

[0101] In an optional step, a set of candidate volumetric fields of view are determined. For example, candidate volumetric fields of view (e.g., candidates) may be areas of the sample 106 that are intended to be candidates for overlay measurements. For example, candidates may be metrology / misalignment targets for one or more layers of the sample, such as box-in-box (BiB) metrology targets, AIM metrology targets, etc.

[0102] In one example, some candidate volumetric fields of view from the set of candidate volumetric fields of view are removed based on the volumetric data to produce a reduced set of candidate volumetric fields of view. For example, if the volumetric data is used to identify a void that overlaps a candidate volumetric field of view, then the overlay targets associated with the candidate volumetric field of view can be skipped for measurement during the overlay measurement process. This can improve efficiency by skipping useless measurements.

[0103] In one example, overlay metrology is performed based on a reduced set of candidate volumetric fields of view.

[0104] In an optional step, the overlay metrology recipe is improved by generating a performance indicator (e.g., a key performance indicator (KPI)) configured for correlating one or more voids 104 with one or more overlay measurements. For example, certain voids 104 may be associated with poor / inaccurate overlay metrology measurements of a metrology target and some voids 104 may appear to have no effect / no relation to overlay. For example, a KPI may be a normalized value (e.g., between 0.00 and 1.00, inclusive) indicating that a characteristic of a void 104 (e.g., size, shape, location, etc.) may be used to predict the likelihood of overlay. For example, a high KPI value may mean that a large void is associated with (and may cause) a large overlay of samples joined together.

[0105] Figure 4 4 is a flow chart illustrating steps performed in a method 400 for generating volume data according to one or more embodiments of the present disclosure. For example, the controller 108 may be configured to communicatively couple to the metrology subsystem 102 of the metrology system 100 and may include a processor 110 configured to execute instructions to cause one or more processors 110 to perform the steps of the method 400.

[0106] In step 402, points of interest are identified across samples 106. In some embodiments, identification of points of interest is based on one or more sources 410 (eg, sources 410a, 410b, 410c, 410d).

[0107] For example, points of interest are based on user sources 410a. For example, a user (e.g., a process engineer) may decide based on other sources such as scanning electron microscope (SEM) images, sample design, or any other source that one or more points of a sample should be further investigated and such points may be considered points of interest.

[0108] In another example, the points of interest are based on PWG tool measurements 410b. For example, the PWG tool may be preconfigured to identify points of interest based on an algorithm, program, etc. and require little or no user input to directly identify such points of interest based on the user's discretion.

[0109] In another example, the points of interest are based on acoustic microscope tool measurements 410c. For example, the acoustic microscope tool may be preconfigured to identify points of interest based on an algorithm, program, etc. and require little or no user input to directly identify such points of interest based on the user's discretion.

[0110] In another example, the focus is based on any other data 410d that may be used for this purpose.

[0111] In step 404, volume data of the sample 106 at the point of interest is generated. For example, any of the steps of the present disclosure (eg, steps 302 and 304), etc., may be used to generate this volume data.

[0112] In some embodiments, at least one of step 406 or step 408 occurs.

[0113] In step 406, the sample manufacturing process is monitored based on the volume data. For example, the volume data may be monitored for breaches exceeding a threshold. For example, the volume data may be a volume profile of a superposition target (e.g., a grating target), wherein each volume data indicates a superposition measurement. For example, the superposition measurement may be determined based on the volume profile of the superposition target. For example, the position of the superposition target relative to an anchor reference (e.g., an edge of a die) or relative to different superposition targets in an underlying layer of the sample 106 may be used to determine the superposition measurement based on the volume data. In addition, multiple superposition measurements may be performed across a sample, across multiple samples, across multiple batches of samples, and the like and may be used to generally monitor the superposition of the manufacturing process of the sample. A predetermined threshold may be determined based on acceptable superposition measurements and if this threshold is breached, an alert is sent to a user.

[0114] In step 408, the sample fabrication process is adjusted based on the volume data. For example, if a threshold is breached, one or more tools of the fabrication process may be adjusted (e.g., recalibrated, realigned). In another example, the adjustment may be any other type of adjustment, such as adjusting the film thickness of the sample 106.

[0115] Reference again Figure 1B and 1C , additional detailed descriptions of embodiments of various components.

[0116] Detectable light 122 may include any type of radiation emitted from sample 106 and / or reference sample 144. For example, detectable light 122 may include light or particles. For example, in some embodiments, detectable light 122 includes measurement beam 168 and / or reference beam 166. For example, detectable light 122 may include a portion of illumination beam 116 that is reflected and / or scattered by sample 106, which may be referred to as measurement beam 168 or be a portion of measurement beam 168. As another example, detectable light 122 may include luminescence induced by absorption of illumination beam 116 by sample 106. As another example, detectable light 122 may include particles from sample 106 in response to illumination beam 116, such as, but not limited to, backscattered electrons or secondary electrons.

[0117] The metrology system 100 may include multiple detectors 124 associated with multiple beam paths generated by one or more beam splitters 136 to facilitate multiple metrology measurements by the metrology system 100. In another embodiment, the detectors 124 may include spectral detectors suitable for identifying wavelengths of radiation emitted from the sample 106.

[0118] The detector 124 may further be positioned at any imaging plane of the metrology system 100. For example, the detector 124 may be positioned at a plane coupled to the sample 106 to produce an image of the sample 106. In another example, the detector 124 may be positioned at a pupil plane (or a combination thereof) to produce a pupil image.

[0119] In another embodiment, the metrology subsystem 102 includes a detector 124 configured to capture light emitted from the sample 106 via the light collection path 120. For example, the detector 124 can receive radiation reflected or scattered (e.g., via specular reflection, diffuse reflection, etc.) from the sample 106. As another example, the detector 124 can receive radiation generated by the sample 106 (e.g., luminescence associated with absorption of the illumination beam 116, etc.). As another example, the detector 124 can receive radiation of one or more diffraction orders (e.g., 0th order diffraction, ±1st order diffraction, ±2nd order diffraction, etc.) from the sample 106.

[0120] In another embodiment, the metrology subsystem 102 may include a plurality of detectors 124 for facilitating the metrology subsystem 102 to perform a plurality of metrology measurements. Figure 1B The metrology subsystem 102 depicted in FIG. 1 can perform multiple simultaneous metrology measurements.

[0121] The illumination source 114 may further provide light having any selected temporal characteristics. In one embodiment, the illumination source 114 includes one or more continuous wave sources for providing a continuous wave illumination beam 116. In another embodiment, the illumination source 114 includes one or more pulse sources for providing a pulsed or otherwise modulated illumination beam 116. For example, the illumination source 114 may include one or more mode-locked lasers, one or more Q-switched lasers, and the like.

[0122] The illumination source 114 may include any type of light source known in the art, but it should be noted that for interferometric type measurements, the measurement beam 168 is generally coherent (rather than incoherent, out of phase, etc.). For example, in one embodiment, the illumination source 114 includes one or more coherent sources, such as, but not limited to, one or more laser sources. In this regard, the illumination source 114 may generate an illumination beam 116 having high coherence (e.g., high spatial coherence and / or temporal coherence). For example, the illumination source 114 may include one or more broadband lasers, such as, but not limited to, one or more supercontinuum lasers or white light lasers. As another example, the illumination source 114 may include one or more narrowband lasers. As another example, the illumination source 114 may include one or more tunable lasers for providing an illumination beam 116 having a tunable spectral intensity. Furthermore, the coherent illumination source 114 may be based on any type of technology or product design. For example, the illumination source 114 may include, but is not limited to, any combination of one or more fiber lasers, one or more diode lasers, or one or more gas lasers.

[0123] It should be noted that the metrology system 100 can generally be used for multiple purposes and, at least for the reasons described, can be configured to also capture non-interferometric measurements using non-coherent illumination. For example, in the same embodiments as above, the illumination source 114 can include one or more low-coherence sources for providing an illumination beam 116 having low or partial coherence (e.g., low spatial and / or temporal coherence). For example, the illumination source 114 can include one or more light emitting diodes (LEDs) or superluminescent LEDs. As another example, the illumination source 114 can include a laser sustained plasma (LSP) source, such as, but not limited to, an LSP lamp, an LSP bulb, or an LSP chamber suitable for housing one or more elements that can emit broadband illumination when excited into a plasma state by a laser source. As another example, the illumination source 114 can include a lamp source, such as, but not limited to, an arc lamp, a discharge lamp, an electrodeless lamp, and the like. Furthermore, the illumination source 114 can include any combination of light sources. In one embodiment, the illumination source 114 includes one or more supercontinuum laser sources for providing broadband illumination and one or more partially coherent high brightness LEDs for filling gaps in the spectrum of the one or more supercontinuum laser sources.

[0124] Reference sample 144 may include any sample suitable for providing reference light in a Linnik interferometer. For example, reference sample 144 may be designed to at least partially replicate sample 106. In this regard, the Linnik interferometer may be balanced and the optical properties of light propagating through reference sample 144 may be the same as or substantially similar to the optical properties of light propagating through sample 106.

[0125] In one embodiment, reference sample 144 may be formed of two or more bonded substrates having the same or similar refractive index as sample 106 (e.g., according to a metrology recipe / method). Such substrates (e.g., substrates 106a, 106b, 106c) may have varying thicknesses. In addition, reference sample 144 may (but not necessarily) include a reflective layer or coating (e.g., a metal coating, etc.) at the interface of the two bonded substrates to increase the reflectivity of the interface. In another embodiment, if sample 106 includes one or more intermediate layers that are proximate to or form buried volume field of view 104, then reference sample 144 may include the same or similar layers. Such intermediate layers may be formed as a multi-layer wafer, with each layer etched to a specific, possibly different, thickness.

[0126] In another embodiment, the reference sample 144 is formed as a single substrate, wherein the bottom surface forms the reference surface. In addition, this reference surface may (but not necessarily) include a reflective layer or coating (such as a metal coating, etc.) to increase the reflectivity of the reference surface. In addition, it should be understood that the reference sample 144 or any portion thereof may have any selected thickness based on the application and properties of the sample 106. For example, in the case where the sample 106 is formed of one or more bonded semiconductor wafers, the reference sample 144 may be formed of one or more semiconductor wafers having a thickness of the top wafer 106a of the sample 106 (e.g., 775 μm, 750 μm, 600 μm, 300 μm, 100 μm, etc.). However, this example is not limiting and the reference sample 144 may have a thickness different from the top wafer 106a of the sample 106.

[0127] In one embodiment, when generating volume data of the buried volume field of view 104 (e.g., inter-sample voids, TSVs), the thickness of the reference sample 144 matches the material thickness above (in the depth direction) the buried volume field of view 104. In this regard, the measurement beam 168 and the reference beam 166 may be configured to pass through the same (or similar) material thickness. For example, similar may mean within 5%, within 10%, etc.

[0128] In another embodiment, the reference sample 144 includes patterned features at one or more locations (eg, the back surface of a single reference substrate or an interface between bonded substrates) for facilitating alignment of the reference sample 144 .

[0129] It should be noted that the phrases "according to a metrology recipe," "according to a recipe," "according to a recipe," and the like may mean that the metrology system 100 is configured to be compatible with a recipe, programmed according to a recipe, and / or the like. A recipe may be a plan, a procedure, a method, a program instruction, and / or the like. Furthermore, a sample, and the like may not necessarily be part of the metrology system 100 according to a metrology recipe, but rather the metrology system 100 may be configured to be compatible with and / or configured for such a sample. For example, "according to a metrology recipe" may mean that the metrology system 100 is configured according to the contents of the program instruction and / or the like.

[0130] Reference again Figure 1A , additional detailed descriptions of embodiments of various components.

[0131] As previously mentioned herein, the controller 108 of the metrology system 100 may include one or more processors 110 and a memory 112. The memory 112 may include program instructions configured to cause the one or more processors 110 to perform the various steps of the present disclosure.

[0132] In another embodiment, the display of the user interface may be configured to display data of the metrology system 100 to the user.

[0133] As previously mentioned herein, the one or more processors 110 of the controller 108 may be communicatively coupled to the memory 112, wherein the one or more processors 110 may be configured to execute a set of program instructions stored in the memory 112, and the set of program instructions may be configured to cause the one or more processors 110 to perform various functions and steps of the present disclosure.

[0134] It should be noted herein that one or more components of the metrology system 100 may be communicatively coupled to various other components of the metrology system 100 in any manner known in the art. For example, the one or more processors 110 may be communicatively coupled to each other and other components via wired (e.g., copper wire, fiber optic cable, etc.) or wireless connections (e.g., RF coupling, IR coupling, WiMax, Bluetooth, 3G, 4G, 4G LTE, 5G, etc.). As another example, the controller 108 may be communicatively coupled to one or more components of the metrology system 100 via any wired or wireless connection known in the art.

[0135] In one embodiment, the one or more processors 110 may include any one or more processing elements known in the art. In this sense, the one or more processors 110 may include any microprocessor-type device configured to execute software algorithms and / or instructions. In one embodiment, the one or more processors 110 may be composed of a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, or other computer system (e.g., a networked computer) configured to execute a program configured to operate the metrology system 100, as described throughout this disclosure. It should be recognized that the steps described throughout this disclosure may be performed by a single computer system or, alternatively, multiple computer systems. In addition, it should be recognized that the steps described throughout this disclosure may be performed on any one or more of the one or more processors 110. In general, the term "processor" may be broadly defined to encompass any device having one or more processing elements that execute program instructions from the memory 112. Furthermore, different subsystems of the metrology system 100 (e.g., the metrology subsystem 102, the interferometer, the controller 108, the user interface, etc.) may include processors or logic elements suitable for performing at least part of the steps described throughout this disclosure. Therefore, the above description should not be construed as limiting the present disclosure, but merely illustrative.

[0136] The memory 112 may include any storage media known in the art suitable for storing program instructions executable by the associated one or more processors 110 and data received from the metrology system 100. For example, the memory 112 may include non-transitory storage media. For example, the memory 112 may include, but is not limited to, ROM, RAM, magnetic or optical storage (such as disks), tapes, solid-state drives, and the like. It should be further noted that the memory 112 may be housed in a common controller housing with the one or more processors 110. In alternative embodiments, the memory 112 may be remotely located relative to the physical location of the processors 110, controller 108, and the like. In another embodiment, the memory 112 retains program instructions for causing the one or more processors 110 to perform the various steps described throughout the present disclosure.

[0137] In one embodiment, the user interface is communicatively coupled to the controller 108. The user interface may include, but is not limited to, one or more desktop computers, tablet computers, smart phones, smart watches, and the like. In another embodiment, the user interface includes a display for displaying data of the metrology system 100 to a user. The display of the user interface may include any display known in the art. For example, the display may include, but is not limited to, a liquid crystal display (LCD), an organic light emitting diode (OLED) based display, or a CRT display. Those skilled in the art will recognize that any display device capable of being integrated with a user interface is suitable for implementation in the present disclosure. In another embodiment, a user may input selections and / or instructions via a user input device of the user interface in response to data displayed to the user.

[0138] All methods described herein may include storing the result of one or more steps of the method embodiment in a memory. The result may include any of the results described herein and may be stored in any manner known in the art. The memory may include any memory described herein or any other suitable storage media known in the art. After storing the result, the result may be accessed in the memory and used by any of the methods or system embodiments described herein, formatted for display to the user, used by another software module, method or system, etc. In addition, the result may be stored "permanently", "semi-permanently", "temporarily" or in a certain period of time. For example, the memory may be a RAM and the result may not be retained in the memory indefinitely.

[0139] It is further contemplated that each of the above method embodiments may include any other steps of any other method described herein. Additionally, each of the above method embodiments may be performed by any of the systems described herein.

[0140] Those skilled in the art will recognize that, for conceptual clarity, the components, operations, devices, objects, and accompanying discussions described herein are used as examples, and various configuration modifications are contemplated. Therefore, as used herein, the specific examples and accompanying discussions set forth are intended to represent their more general class. In general, the use of any specific example is intended to represent its class, and the non-inclusion of specific components, operations, devices, and objects should not be considered limiting.

[0141] As used herein, directional terms such as "top", "bottom", "above", "below", "up", "upward", "down", "below", and "downward" are intended to provide relative positions for descriptive purposes and are not intended to specify an absolute reference system. Various modifications to the described embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments.

[0142] With respect to the use of substantially any plural and / or singular terms herein, those skilled in the art may translate from the plural to the singular and / or from the singular to the plural, depending on the context and / or application. For clarity, the various singular / plural arrangements are not explicitly set forth herein.

[0143] The objectives described herein sometimes illustrate different components contained in or connected to other components. It should be understood that such depicted architectures are for demonstration only and in fact many other architectures that realize the same functionality can be implemented. In a conceptual sense, any arrangement of components for realizing the same functionality is effectively "associated" to realize the desired functionality. Therefore, any two components combined to realize a specific functionality herein can be considered to be "associated" with each other to realize the desired functionality, regardless of the architecture or intermediate components. Similarly, any two components so associated can be considered to be "connected" or "coupled" to each other to realize the desired functionality, and any two components that can be so associated can also be considered to be "coupleable" to each other to realize the desired functionality. Specific examples of "coupleable" include (but are not limited to) physically matable and / or physically interactive components and / or wirelessly interactive and / or wirelessly interactive components and / or logically interactive and / or logically interactive components.

[0144] In addition, it should be understood that the present invention is defined by the appended claims. It should be understood by those skilled in the art that, in general, the terms used herein and particularly in the appended claims (e.g., the body of the appended claims) are generally intended to be "open" terms (e.g., the term "including" should be interpreted as "including (but not limited to)", the term "having" should be interpreted as "having at least", the term "include" should be interpreted as "including (but not limited to)", etc.). It should be further understood by those skilled in the art that if a specific number of claim recitations is intended to be introduced, then this intention is to be explicitly stated in the claim, and if such a statement is not made, then such intention does not exist. For example, as an aid to understanding, the appended claims may contain the use of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be interpreted as implying that the introduction of a claim recitation by the indefinite article "a" limits any particular claim containing such introduced claim recitation to an invention containing only one such recitation, even if the same claim contains the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" (e.g., "a" should generally be interpreted as meaning "at least one" or "one or more"); the same applies to the use of definite articles used to introduce claim recitations. In addition, even if a specific number of introduced claim recitations is explicitly recited, those skilled in the art will recognize that such recitation should generally be interpreted as meaning at least the recited number (e.g., the bare recitation "two recitations" without other modifiers generally means at least two recitations or two or more recitations). Furthermore, in examples where a convention similar to “at least one of A, B, and C, etc.” is used, this construction is generally intended to be what one of ordinary skill in the art would understand (e.g., “a system having at least one of A, B, and C” would include, but not be limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). In examples where a convention similar to “at least one of A, B, or C, etc.” is used, this construction is generally intended to be what one of ordinary skill in the art would understand (e.g., “a system having at least one of A, B, or C” would include, but not be limited to, systems having only A, only B, only C, both A and B, both A and C, both B and C, and / or both A, B, and C, etc.). One of ordinary skill in the art would further understand that virtually any disjunctive term and / or phrase presenting two or more alternatives, whether in the detailed description, claims, or drawings, would be understood to contemplate the possibility of including one of the terms, either of the terms, or both of the terms. For example, the phrase "A or B" should be understood to include the possibilities of "A" or "B" or "A and B."

[0145] It is believed that the present disclosure and many of its attendant advantages will be understood from the foregoing description, and it will be appreciated that various changes may be made to the form, construction and arrangement of components without departing from the disclosed objects or sacrificing all of its material advantages. The forms described are for illustration only and the appended claims are intended to cover and encompass such changes. Furthermore, it should be understood that the present disclosure is defined by the appended claims.

Claims

1. A metrology system comprising: The metrology subsystem includes: a detector configured for multi-pixel imaging; an illumination source configured to generate an illumination beam; a beam splitter configured to split the illumination beam into a measuring beam propagating in a measuring branch and a reference beam propagating in a reference branch; a measuring objective lens configured to direct the measuring beam to a sample; one or more illumination optics configured to illuminate a volumetric field of view of the sample with the measurement beam through the measurement objective; and a reference objective lens configured to direct the reference beam to a reference sample; and wherein the metrology subsystem is configured to image the volumetric field of view of the sample on the detector based on interference of the measurement beam with the reference beam according to a metrology recipe, a controller communicatively coupled to the detector, wherein the controller includes one or more processors configured to execute program instructions to cause the one or more processors to: receiving a plurality of images from scans of the sample at a plurality of focal planes positioned along a depth direction of the sample to generate, via the detector of the metrology subsystem, the plurality of images of the volumetric field of view of the sample at the plurality of focal planes; and The plurality of images are gathered to generate volumetric data of the volumetric field of view of the sample.

2. The metrology system of claim 1, wherein the sample is formed of a first substrate and a second substrate, the second substrate being bonded to the first substrate at an interface, wherein the volumetric field of view is located within the sample.

3. The metrology system of claim 2, wherein the metrology subsystem comprises a Linnik interferometer.

4. The metrology system of claim 3, wherein the Linnik interferometer comprises an infrared interferometer.

5. The metrology system of claim 3, wherein the Linnik interferometer comprises a short wave infrared (SWIR) interferometer.

6. The metrology system of claim 2, wherein the program instructions are further configured to identify one or more voids in the volumetric field of view of the sample based on the volume data, wherein the one or more voids are located at the interface.

7. A metrology system according to claim 2, wherein the program instructions are further configured to determine characteristics of one or more voids in the volumetric field of view of the sample based on the volume data, wherein the one or more voids are located at the interface.

8. The metrology system of claim 2, wherein according to the metrology recipe, the sample comprises a die-to-wafer (D2W) bonding sample.

9. The metrology system of claim 2, wherein according to the metrology recipe, the sample comprises a die-to-die (D2D) bonding sample.

10. The metrology system of claim 2, wherein according to the metrology recipe, the sample comprises a wafer-to-wafer (W2W) bonding sample.

11. The metrology system of claim 1, wherein the volumetric field of view of the sample comprises a volumetric field of view of a surface shape of the sample, and the sample is in a pre-engaged state according to the metrology recipe.

12. The metrology system of claim 11, wherein the volume data comprises a height map of the surface shape of the sample.

13. The metrology system of claim 11, wherein the metrology subsystem comprises a Linnik interferometer.

14. The metrology system of claim 13, wherein the detector is configured to operate in the visible spectrum of light.

15. The metrology system of claim 13, wherein the Linnik interferometer is configured to operate in the infrared spectrum of light.

16. The metrology system of claim 13, wherein the Linnik interferometer is configured to operate in the short wave infrared (SWIR) spectral range of light.

17. The metrology system of claim 1, wherein the volumetric field of view of the sample comprises a volumetric field of view of a through silicon via (TSV) of the sample.

18. The metrology system of claim 1, wherein the volumetric field of view of the sample comprises a volumetric field of view of a superimposed target of the sample.

19. The metrology system of claim 1 , wherein receiving the plurality of images from the scans of the sample at the plurality of focal planes comprises at least one of: moving the sample via a translation stage; moving the reference sample via a reference translation stage; or Adjusting the phase of the reference beam of the reference branch.

20. The metrology system of claim 1, wherein the metrology system further comprises a photodiode configured to focus the detector.

21. The metrology system of claim 20, wherein the photodiode is configured to receive a photodiode beam associated with the interference of the measurement beam and the reference beam from the beam splitter, wherein the photodiode is configured to generate sample positioning data.

22. The metrology system of claim 21, wherein the photodiode beam is derived from the illumination beam from the illumination source and a second illumination beam from a second illumination source.

23. The metrology system of claim 21, wherein the metrology subsystem further comprises a modulator configured to modulate the photodiode light beam directed to the photodiode, the modulator comprising at least one of: Binary Phase Filter (BPF); Full Width Half Maximum (FWHM) filter; or Ring mask.

24. The metrology system of claim 21, wherein the metrology subsystem further comprises a modulator configured to modulate the photodiode light beam directed to the photodiode, the modulator comprising a binary phase filter (BPF), a full width at half maximum (FWHM) filter, and an annular mask.

25. A metrology system according to claim 1, wherein the area of ​​the measurement beam directed to the sample as seen in a focal plane of the multiple focal planes is larger than the volumetric field of view of the sample, and wherein the multiple images include an imaging area larger than the volumetric field of view of the sample.

26. The metrology system of claim 1, wherein the metrology system further comprises at least one of a review tool or a patterned wafer geometry (PWG) tool, the PWG tool configured to image the entire surface of the sample at one time, wherein the program instructions are further configured to identify points of interest across the sample prior to receiving the plurality of images, Wherein receiving the plurality of images is based on the point of interest.

27. A metrology system according to claim 26, Wherein identifying the points of interest is performed using the at least one of the review tool or the patterned wafer geometry (PWG) tool.

28. The metrology system of claim 27, wherein the review tool is an acoustic microscope.

29. The metrology system of claim 26, wherein identifying the point of interest is based on user input.

30. The metrology system of claim 26, wherein the program instructions are further configured to monitor a sample manufacturing process based on the volume data.

31. The metrology system of claim 26, wherein the program instructions are further configured to adjust a sample manufacturing process based on the volume data.

32. The metrology system of claim 1, wherein the illumination light beam comprises a first illumination spectral range that partially overlaps a second illumination spectral range, such that the metrology subsystem comprises a multi-wavelength (MWL) metrology subsystem.

33. The metrology system of claim 32, wherein the beam splitter comprises a wavelength filter beam splitter such that the reference beam comprises the first illumination spectral range and the measurement beam comprises the second illumination spectral range.

34. The metrology system of claim 1, wherein the illumination beam comprises an annular illumination beam.

35. The metrology system of claim 1, wherein the illumination beam is displaced across a pupil plane of the metrology subsystem.

36. A method comprising: manufacturing a sample according to a manufacturing process, wherein a surface shape of the sample includes a concave shape; generating volumetric data of the surface shape of the sample using a metrology subsystem including a detector, wherein the metrology subsystem includes a Linnik interferometer, wherein the detector includes a multi-pixel detector; engaging the surface shape of the sample with a second sample configured to engage with the sample; and The manufacturing process is adjusted based on the volume data.

37. The method of claim 36, further comprising determining a characteristic of the surface shape based on the volume data.

38. The method of claim 36, wherein generating volumetric data is performed in the visible spectrum of light.

39. The method of claim 36, wherein the metrology subsystem includes an infrared interferometer, wherein generating volume data is performed in the infrared spectrum of light.

40. The method of claim 39, wherein the infrared interferometer comprises a short wave infrared (SWIR) interferometer, wherein generating volumetric data is performed in the short wave infrared spectral range of light.

41. A method comprising: scanning the sample at a plurality of focal planes positioned along a depth direction of the sample to generate a plurality of images of a volumetric field of view of the sample at the plurality of focal planes via a detector of a metrology subsystem, wherein the detector comprises a multi-pixel detector; and aggregating the plurality of images to generate volumetric data of the volumetric field of view of the sample, The metrology subsystem includes a Linnik interferometer.

42. The method of claim 41, wherein the Linnik interferometer comprises an infrared interferometer.

43. The method of claim 41, wherein the Linnik interferometer comprises a short wave infrared (SWIR) interferometer.

44. The method of claim 41, further comprising identifying one or more voids based on the volume data.

45. The method of claim 44, further comprising: determining a set of candidate volumetric fields of view for the sample; removing candidate volumetric fields of view from the set of candidate volumetric fields of view based on the volumetric data to produce a reduced set of candidate volumetric fields of view; and performing superposition metrology based on the reduced set of candidate volumetric fields of view.

46. ​​The method of claim 44, further comprising improving the superimposed metrology formula by: A performance indicator configured to correlate the one or more gaps with the overlay measurement is generated.

47. The method of claim 41, further comprising determining a characteristic of one or more voids based on the volume data.

48. The method of claim 41, wherein the volumetric field of view of the sample comprises a volumetric field of view of a through silicon via (TSV) of the sample.

49. The method of claim 41, wherein the volumetric field of view of the sample comprises a volumetric field of view of an object superimposed on the sample.

50. The method of claim 41, the scanning of the sample at the plurality of focal planes comprising at least one of: moving the sample via a translation stage; Moving the reference sample via a reference translation stage; or Adjust the phase of the reference beam of the reference branch.

51. The method of claim 41, the metrology subsystem comprising a photodiode configured to focus the detector.

52. The method of claim 51, wherein the photodiode is configured to receive a photodiode beam from a beam splitter associated with interference of a measurement beam in a measurement branch with a reference beam from a reference branch, wherein the photodiode generates sample positioning data.

53. The method of claim 52, wherein the photodiode light beam is derived from an illumination light beam from an illumination source and a second illumination light beam from a second illumination source.

54. The method of claim 52, further comprising modulating the photodiode light beam directed to the photodiode via a modulator, wherein the modulator comprises at least one of: Binary Phase Filter (BPF); Full Width Half Maximum (FWHM) filter; or Ring mask.

55. The method of claim 52, further comprising modulating the photodiode beam directed to the photodiode via a modulator, wherein the modulator comprises a binary phase filter (BPF), a full width at half maximum (FWHM) filter, and an annular mask.

56. The method of claim 41, wherein the volumetric field of view is completely contained within a cross-sectional area of ​​a measurement beam directed to the sample such that the volumetric field of view is fully illuminated.

57. The method of claim 41, further comprising identifying points of interest across the sample prior to the scanning, Wherein scanning the sample to generate the plurality of images is based on the point of interest.

58. The method of claim 57, wherein identifying the points of interest is performed via at least one of a review tool or a patterned wafer geometry (PWG) tool, the PWG tool configured to image the entire surface of the sample at one time.

59. The method of claim 58, wherein the review tool is an acoustic microscope.

60. The method of claim 57, wherein identifying the point of interest is based on user input.

61. The method of claim 57, further comprising monitoring a sample manufacturing process based on the volume data.

62. The method of claim 57, further comprising adjusting a sample fabrication process based on the volume data.

Images