System and method for acquiring alignment measurements of structure engaging sample

Abstract

Systems and methods for acquiring measurements of a structure engaging a sample are disclosed. Such systems and methods may include determining a first registration measurement of a first registration structure of a first sample with a first interface target structure and a second registration measurement of a second sample prior to coupling the first sample and the second sample together. Such systems and methods may include, after this coupling of the sample, determining a third registration measurement of the coupled sample at least in part by measuring the first registration structure through a top surface of the first sample. Such systems and methods may include obtaining an overlay measurement based on the first registration measurement, the second registration measurement, and the third registration measurement. Such systems and methods may include adjusting an inter-sample coupling recipe based on the overlay measurements, wherein the inter-sample coupling recipe may include a final bonding recipe.

Description

Technical Field

[0001] The present disclosure relates generally to metrology, and more particularly, the present disclosure relates to metrology of coupled 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., tailoring to specific device types (e.g., 3D NAND and DRAM memory devices, logic CPU and GPU devices, I / O devices, etc.), manufacturing several types of devices 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.).

[0003] One method for implementing 3D IC design is to fabricate the structure on two separate samples and then join them together with interconnects near the interface. This technique can facilitate the integration of complex structures because the two samples can be fabricated separately and joined in a subsequent process. For example, this combination can be temporary or permanent. In addition, this combination can be centralized or direct. For example, centralized D2W (Co-D2W) combination can involve joining multiple dies in a single placement operation. Direct combination can involve sequential pick-up and placement of individual dies. Combining more and more dies with different functions (e.g., 5, 10, 100) on a single joined sample is a growing trend in the industry.

[0004] This trend is also driven by the desire to overcome the communication bottleneck between different areas of the sample and between different functions by creating dense interconnects between the bonded samples. These dense interconnects may require tight overlay alignment tolerances.

[0005] Overlay metrology between two samples, such as may be performed for alignment, faces several challenges. Generally, a sample to be bonded to another sample is either cut from a wafer or individually bonded. For example, samples may be cut from a wafer (such as in a D2W bonding process) and individually picked and placed or centrally coupled (such as pre-aligned and placed simultaneously on a glass or silicon (Si) substrate) or pre-cut bonded (such as in a W2W bonding process). There are tradeoffs and various techniques for each type of process.

[0006] In general, W2W bonding is limited by the accuracy of structural alignment because the structure changes more from one end of the wafer to the other than a smaller sample (such as a die). However, W2W allows the use of non-functional space (such as a scribe line area) for alignment purposes. For example, a technique for W2W bonding can use a dedicated "penetration" hole in the scribe line area of ​​the wafer to facilitate alignment. Another technique for W2W bonding uses an etching process to carefully etch deep grooves in the wafer, so that a thin, more translucent point is produced for alignment purposes. However, this technique is destructive, time-consuming and space-consuming. W2W bonding can also limit the final product yield due to the use of defective or non-functional dies in any of the bonded wafers.

[0007] D2W bonding, on the other hand, may allow for tighter interconnect alignment due to smaller variations across the die but in the past has used dedicated non-functional overlay targets in active areas (e.g., electrically functional areas, such as those used by logic gates and transistors). Active areas are often needed for alignment because the die have been cut from the wafer and therefore generally do not have scribe line areas for alignment purposes. However, it is not practical to directly measure the alignment of structures in the active area at the interface between bonded samples from the outside because the samples may not be transparent enough for optical microscopy or scatterometry overlay techniques.

[0008] It should be noted that many factors can reduce the likelihood that structures buried deep at the interface formed between two mating samples will become measurable for overlay purposes. For example, factors that reduce measurability may include, but are not limited to, increased thickness of the sample, increased doping of the sample material, opaque metal layers, density of structures, etc. In general, the likelihood that one or more of these factors will limit measurability increases as designs become more complex and more layers are used.

[0009] Some techniques for aligning dies in a D2W bonding process use relatively large (e.g., 30 micrometers (um) width) dedicated (e.g., non-electrically functional) overlay targets in the active area of ​​the sample. Measuring these overlay targets may require the absence of obstructing features above and / or below the overlay targets to create non-functional columnar volumes along the depth direction of the sample and occupy valuable active area. Furthermore, as the thickness of the sample increases due to more layers, additional layers must also reserve space for measuring the dedicated overlay target stack.

[0010] Other obstacles to measuring (e.g., imaging) structures at the bonding interface may include poor optical properties (e.g., low transparency) of adhesive material layers used in wafer carrier bonding. Additional obstacles to bonding alignment may generally include tight overlay specification tolerances and increasing density of interconnects as the size of interconnects decreases.

[0011] Therefore, it is desirable to accurately determine the alignment of samples (eg, dies) for coupling (eg, bonding) to overcome the above-mentioned drawbacks. Summary of the invention

[0012] A metrology system according to one or more embodiments of the present disclosure is disclosed. In one illustrative embodiment, the metrology system includes a metrology subsystem configured to obtain superposition measurements of an interface target on a coupled sample. In one illustrative embodiment, the metrology subsystem includes a controller communicatively coupled to the metrology subsystem. 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 determine a first registration measurement between a first interface target structure and a first registration structure positioned on a different layer than the first interface target structure on a first sample before coupling with a second sample to form a coupled sample, wherein the first registration structure is configured to be measured by the metrology subsystem through a top surface of the first sample opposite to a coupleable surface of the first sample. In another illustrative embodiment, the one or more processors are configured to execute program instructions to cause the one or more processors to determine a second registration measurement between a second interface target structure and a second registration structure on the second sample before coupling with the first sample to form the coupled sample, wherein the second registration structure is configured to be unobstructed by the first sample when the first sample is coupled to the second sample to form the coupled sample. In another illustrative embodiment, the one or more processors are configured to execute program instructions to cause the one or more processors to determine a third registration measurement between the second registration structure on the second sample and the first registration structure on the first sample on the coupled sample after the first sample is coupled to the second sample, at least in part by measuring the first registration structure through a top surface of the first sample. In another illustrative embodiment, the one or more processors are configured to execute program instructions to cause the one or more processors to acquire the superposition measurement of the interface target based on the first registration measurement, the second registration measurement, and the third registration measurement.

[0013] A method according to one or more embodiments of the present disclosure is disclosed. In one illustrative embodiment, the method may include, but is not limited to, determining, via a metrology subsystem, a first registration measurement between a first interface target structure of a first sample and a first registration structure before coupling the first sample to the second sample to form a coupled sample. In one illustrative embodiment, the method may include, prior to coupling the first sample to the second sample to form the coupled sample, determining, via the metrology subsystem, a second registration measurement between a second interface target structure of the second sample and a second registration structure.

[0014] In one illustrative embodiment, the method may include coupling the first sample to the second sample to form the coupled sample. In one illustrative embodiment, the method may include determining, on the coupled sample, via the metrology subsystem, a third registration measurement between the second registration structure on the second sample and the first registration structure on the first sample, after the first sample is coupled to the second sample, at least in part by measuring the first registration structure through the top surface of the first sample. In one illustrative embodiment, the method may include acquiring the overlay measurement of the interface target based on the first registration measurement, the second registration measurement, and the third registration measurement.

[0015] It should be understood that both the foregoing general description and the following detailed description are for illustration and explanation 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

[0016] Those skilled in the art may better understand the numerous advantages of the present disclosure by referring to the accompanying drawings.

[0017] Figure 1 is a conceptual view illustrating a metering system according to one or more embodiments of the present disclosure.

[0018] Figure 2A is a side view of a coupled sample including a first sample coupled to a second sample according to one or more embodiments of the present disclosure.

[0019] Figure 2B According to one or more embodiments of the present disclosure Figure 2A Side view of the first sample.

[0020] Figure 2C According to one or more embodiments of the present disclosure Figure 2A Side view of the second sample.

[0021] Figure 3is a flow chart illustrating steps performed in a method for acquiring superposition measurements of coupled samples in accordance with one or more embodiments of the present disclosure.

[0022] Figure 4A According to one or more embodiments of the present disclosure Figure 2B Top view of the first sample.

[0023] Figure 4B According to one or more embodiments of the present disclosure Figure 2A Top view of the coupled sample.

[0024] Figure 5A is a side view of a first sample before being cut from a wafer according to one or more embodiments of the present disclosure.

[0025] Figure 5B According to one or more embodiments of the present disclosure, a first sample is cut from a wafer. Figure 5A Side view of the coupled sample of the first sample.

[0026] Fig. 6A is a side view of a first sample before being cut from a wafer according to one or more embodiments of the present disclosure.

[0027] Figure 6B According to one or more embodiments of the present disclosure, a first sample is cut from a wafer. Fig. 6A Side view of the coupled sample of the first sample. DETAILED DESCRIPTION

[0028] 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 specific embodiments and specific features of the present disclosure. The embodiments described herein should be regarded as illustrative rather than limiting. It should be readily apparent to those skilled in the art that various changes and modifications in form and detail may be made without departing from the spirit and scope of the present disclosure.

[0029] Embodiments of the present disclosure relate to systems and methods for measuring superposition of structures by combining registered measurements of various reference structures relative to the structures. For example, the measured structure may include structure at an interface between two mating samples. The interface may be defined as formed by the faces of each sample when placed against each other. One challenge in measuring superposition of structures at or near an interface is that after coupling one sample to another, such interface structures are deep within the coupled samples and the cumulative thickness of the layers above such structures may not exist sufficient to allow for measurement of the structure.

[0030] For the purposes of this disclosure, the term "imaging" and the like are not necessarily limited to optical techniques, but are used for simplicity and are generally interchangeable with the term "measurement". Measurement includes any type of signal collection that supports acquisition of registered or overlaid measurements. For example, such signal collection includes techniques based on scatterometry and imaging in visible, infrared, and x-ray (tomography) wavelengths. In addition, such collection includes techniques based on scanning electron microscopy (SEM).

[0031] Although it is generally impractical to directly measure the structure at the interface through the top surface of the sample, it is contemplated that measurements of the structure at the interface may be provided by mathematically combining other measurements. In an embodiment, a plurality of registration measurements acquired prior to the coupling operation may be stored and sent to the coupling operation along with the sample. Such pre-coupling measurements may be combined with one or more post-coupling measurements to mathematically calculate measurements of the structure at the interface of the coupled sample. In this regard, measurements of structures buried within the coupled sample that are impractical to image after coupling may still be determined by combining various other measurements acquired before and after coupling. Benefits of embodiments include facilitating proper alignment of the sample prior to the permanent bonding process and increasing the likelihood of properly functioning interconnect devices.

[0032] For purposes of this disclosure, top surface refers to the surface opposite the coupleable surface, the "back side" surface of the first fabricated layer of a specimen, and the like.

[0033] Before a sample is mated to another sample, embodiments of the present disclosure track registration measurements between structures at the interface and buried structures in an earlier fabricated lower layer. Thus, when the sample is flipped, the buried structure is closer to the top / outer surface and easier to image / measure. In addition, because the registration measurements between the buried structure and the structure at the interface (e.g., the bonding interface) are known, the measurement of the buried structure can be combined with the registration measurement to mathematically determine the position of the structure at the interface and thus determine the superposition. In this regard, the superposition of the structure at the interface can be determined indirectly, even if the structure at the interface cannot be imaged directly. In an additional embodiment of the present disclosure, the registration measurements of the structure at the interface are tracked relative to the edge of the sample. In this regard, even if the sample is flipped for bonding and the structure at the interface cannot be imaged directly, the measurement of the edge can also be used to mathematically determine the position of the structure at the interface and thus determine the superposition. In an additional embodiment of the present disclosure, the registration measurements of the structure at the interface are tracked relative to the intermediate structure in the intermediate layer of the sample. In this regard, even if the sample is flipped for bonding and the structure at the interface cannot be imaged directly, the measurement of the intermediate structure can also be used to mathematically determine the position of the structure at the interface and thus determine the superposition.

[0034] Furthermore, while various components may be described or depicted as being "coupled" or "connected," any two components that can be so associated may also be considered "coupleable" to each other to achieve the desired functionality. Specific examples of coupleable include, but are not limited to, physically matable and / or physically interactable components. Furthermore, while various components may be depicted as being directly connected or coupled, direct connection or direct coupling is not required. For example, components may be indirectly coupled (e.g., coupleable) through an interface, device, layer (e.g., adhesive), or intermediate component (whether physically (e.g., physically mating) or otherwise).

[0035] For purposes of the present disclosure, the terms "couple," "coupled," "coupling," "coupling process," and the like do not necessarily mean joining, fusion, or permanent attachment and may also mean temporary coupling. For example, the term "coupled" may simply mean samples that are aligned and placed (e.g., temporarily and non-destructively reversibly placed) relative to each other. For example, in an embodiment, a first sample may be non-destructively decoupled from a second sample even after a coupling step. For example, "coupled" may mean gently clamping together using a clamping assembly. For example, a different permanent joining step may occur at a later time, which includes applying heat and pressure to fuse the material of the first sample to the second sample. However, coupling or coupled may mean a permanent joining process or a permanent joining that uses heat and pressure to fuse the samples and which cannot be easily or non-destructively reversed and / or requires a heating process to melt the material and decouple the samples.

[0036] For purposes of this disclosure, the terms "structure," "feature," and the like may generally refer to any structure that can be measured. For example, a structure may generally refer to, but is not limited to, an electrically functional structure (e.g., a portion of a logic gate or transistor), a non-functional structure (e.g., a dedicated overlay target, an edge of a die / wafer), or any other measurable structure. Therefore, it should be understood that the examples of structures in this disclosure are provided for illustrative purposes only and should not be construed as limiting.

[0037] For the purposes of this disclosure, the term "registration measurement" and the like may refer to a measurement between two structures. For example, a registration measurement may refer to the distance between two structures projected onto two planes along one direction (e.g., X direction, Y direction). For example, this direction may be orthogonal to the depth direction through the layer of the sample. In this regard, the registration measurement may be the projected "X component" of the vector between the two structures. For example, the registration measurement may be based on a single image, where the two structures are within the field of view of the image and the distance between the structures in the image may be used to derive the registration measurement between the structures. In another example, the registration measurement is obtained as follows: first, the position of the corresponding structure is imaged; then, the sample is moved by a precisely known distance relative to the metrology subsystem; and finally, different structures are imaged. The position of the structure in the image (e.g., the center position) and the known distance of the sample movement may be used to obtain the registration measurement between the structures. In another example, two or more registration measurements may be used to mathematically determine the registration measurement between three or more structures. For example, the registration measurement between the first and second structures and the X component of the registration measurement between the second structure and the third structure may be combined to determine the X component registration measurement between the first and third structures. It should be noted that examples of registration measures in this disclosure are provided for illustrative purposes and should not be construed as limiting, and any number of registration measures for any number and type of structures (whether or not based on other registration measures) may be combined to determine registration measures between various structures.

[0038] Reference Figures 1 to 6B , describing a method for acquiring a coupling sample (e.g. Figure 2A In an embodiment, the system and method can be used to augment existing systems and methods for metrology (eg, overlay metrology) and / or inspection of a sample.

[0039] Figure 1 A conceptual diagram illustrating a metering system 100 according to one or more embodiments of the present disclosure.

[0040] In an embodiment, the metrology system 100 includes a metrology subsystem 102. The metrology system 100 may generally include any number or type of metrology subsystems 102, and each metrology subsystem 102 may generally include any number or type of subsystems (eg, metrology and / or verification subsystems).

[0041] In an embodiment, the sample 106 may include any number and type of samples known in the art. For example, the sample 106 may be a pre-bonded substrate (e.g., a pre-bonded die), a coupled sample formed by two substrates (e.g., die to wafer, wafer to wafer, die to die, etc.), a pre-cut wafer, or any other type or combination of samples. For example, the sample 106 may include a coupled sample formed by two substrates coupled together at an interface. In addition, the sample 106 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 sample 106 includes a wafer (e.g., a semiconductor wafer). In an embodiment, the sample 106 may include a coupled sample. For example, the coupled sample may include but is not limited to a wafer sample and a die sample coupled at an interface. In this regard, the sample 106 (e.g., a coupled sample) may include two or more samples 106 coupled together. It should be noted that although sample 106 may be described as a "die", this term is non-limiting and any description and methods herein may apply to a "chiplet", a "chip", multiple dies / chiplets coupled together in a plane, a full wafer, a partially cut wafer, multiple stacked bonded dies / chiplets / wafers configured to be bonded to another wafer, etc.

[0042] In an embodiment, the metrology system 100 includes a controller 108. The controller 108 may include one or more processors 110 configured to execute program instructions maintained on a memory 112 (e.g., a memory medium). Furthermore, the controller 108 may be communicatively coupled with any of the components of the metrology system 100, including but not limited to the metrology subsystem 102 and any other subsystems. 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.

[0043] Figure 2A A side view of a coupled sample 200 including a first sample 202 coupled to a second sample 204 is illustrated in accordance with one or more embodiments of the present disclosure. In an embodiment, the first sample 202 includes a coupleable face 214 opposite a top face 216. In an embodiment, the first sample 202 includes various structures, such as but not limited to a first interface target structure 206 at or near an interface 224. A challenge in measuring the coupled sample 200 is that it is generally not practical to measure structures at or near the interface 224 through the top face 216. Therefore, it may be impractical to measure the alignment of interconnect interface structures of two samples coupled together.

[0044] For purposes of this disclosure, the term "at an interface" may be interpreted to encompass structures positioned at, near, and / or across an interface.

[0045] According to one or more embodiments of the present disclosure, Figure 2Billustrates a side view of a first specimen 202 and a first registered measurement m1, and Figure 2C A side view of the second sample 204 and the second registration measurement m2 is illustrated. For example, the first registration measurement m1 and the second registration measurement m2 may be acquired before the first sample 202 is coupled to the second sample 204. The registration measurements m1, m2 may be mathematically combined to obtain Figure 2A For example, the superposition measurement m4 of the structures 206, 212 can be mathematically determined by combining the registration measurements m1, m2, and m3, even if the structures 206, 212 at the interface cannot be imaged directly (e.g., can be measured through the top surface 216 of the first sample 202). For example, the mathematical combination can represent the addition and / or subtraction of vectors of the measurements.

[0046] For purposes of this disclosure, the term “overlay measurement” and the like encompasses measurable errors in the alignment of centers of symmetry of structures (eg, structures 206 , 212 ).

[0047] In an embodiment, a superposition measurement m4 of a structure at the interface 224 may be provided (e.g., calculated) by mathematically combining other measurements. For example, the first interface target structure 206 may be a structure that is more suitable for measurement / imaging through the top surface 216. In addition, the measurement m3 of the first interface target structure 206 may be acquired after coupling of the samples 202, 204. In addition, the measurement acquired before coupling the samples 202, 204 may be combined with the measurement m3. For example, in an embodiment, Figure 2B The measurement of m1 and Figure 2C The measurement m2 is an example of a measurement acquired before coupling the samples 202 , 204 .

[0048] Figure 3 Flowchart illustrating steps performed in a method 300 for acquiring a superposition measurement m4 of a coupled sample 200 in accordance with one or more embodiments of the present disclosure.

[0049] In step 302, return to reference Figure 2B , determining a first registration measurement m1 between the first interface target structure 206 of the first sample 202 and the first registration structure 208 .

[0050] In an embodiment, step 302 may be performed by any metrology tool known in the art. For example, step 302 may be performed using an optical metrology subsystem of the metrology subsystem 102 or an electron beam metrology subsystem of the metrology subsystem 102 (eg, a scanning electron microscope metrology subsystem, etc.).

[0051] In an embodiment, step 302 may be performed in any step of the manufacturing process. For example, step 302 may be performed in one or more post-development inspection (ADI) steps of one or more layers (e.g., layers 218, 226, 228) of the first sample 202. For example, step 302 may be performed in one or more post-etching inspection (AEI) steps of one or more layers of the first sample 202.

[0052] In an embodiment, step 302 is performed before coupling the first sample 202 to the second sample 204 to form a coupled sample. For example, step 302 may be performed before coupling step 306. In this regard, the first sample 202 may be flipped over for coupling from a “front side” relative to the first sample 202 (e.g., facing the front side). Figure 2B 2 (in the negative Z direction shown in FIG. 2 ). This may allow online measurement (eg, during the fabrication of a layer of the first sample 202).

[0053] In an embodiment, an interface object (e.g. Figure 2A The interface target 232 of the first sample 202 includes a first interface target structure 206 associated with the couplable surface 214 of the first sample 202 and a second interface target structure 212 associated with the couplable surface 234 of the second sample 204. For example, when the first sample 202 is coupled to the second sample 204, the first interface target structure 206 and the second interface target structure 212 can be positioned at or near the interface 224. For example, in an embodiment, the first interface target structure 206 is configured to be a portion of the interface target 232 for which the overlay measurement m4 is obtained. For example, the interface target 232 can include or be an AIM overlay target, a box-in-box (BiB) overlay target, a side-by-side overlay target, etc. However, such descriptions and examples are not limiting and the interface target 232 can include any structure, such as an electrically functional interconnect element (such as a through silicon via (TSV), other interconnect structures, logic gates, transistors, etc.).

[0054] In an embodiment, the coupleable face 214 is the face where the interconnect is configured to couple to the second sample. In an embodiment, the coupleable face 214 is the face that was most recently fabricated during the fabrication of the first sample 202. For example, the opposite side of the first sample 202 may include a top surface 216.

[0055] In embodiments, the first sample 202 may include any number (e.g., 2, 3, 10, 100) of layers. For example, the first sample 202 may include a first layer 218, one or more intermediate layers 226, and a coupling layer 228. In embodiments, the first interface target structure 206 may be, but is not limited to, positioned in the coupling layer 228. For example, the first interface target structure 206 may be located at and / or near the coupling surface 214 of the first sample 202. In other embodiments, the first interface target structure 206 may be in other layers, such as a layer that is not practical to image through the top surface 216 for registration measurement purposes. For example, this layer may be the intermediate layer 226 near the coupling layer 228.

[0056] In step 304, return to reference Figure 2C , determine a second registration measurement m2 between the second interface target structure 212 of the second sample 204 and the second registration structure 220. For example, Figure 2C , 4B , 5B and 6B show non-limiting examples of the second registration measurement m2. In addition, a non-limiting example of the second registration structure 220 is Figure 2A , 5B and the scribe line structure shown in FIG. 6B.

[0057] In an embodiment, step 304 may be performed by any metrology tool known in the art, such as but not limited to an optical metrology subsystem of the metrology subsystem 102 or an electron beam metrology subsystem of the metrology subsystem 102 (e.g., a scanning electron microscope metrology subsystem, etc.). For example, step 304 may be performed in the visible spectrum of light via one or more optical metrology subsystems 102. For example, determining the second registration measurement m2 of step 304 may include imaging both the second interface target structure 212 and the second registration structure 220 in the visible spectrum of light via the optical metrology subsystem of the metrology subsystem 102.

[0058] In an embodiment, the step 304 of determining the second registration measurement m2 is performed using any of a variety of techniques for acquiring measurements. For example, the second registration measurement m2 may be based on a single image, where two structures 212, 220 are within the field of view of the image and the distance between the structures 212, 220 in the image may be used to derive the second registration measurement m2. In another example, the second registration measurement m2 is acquired by first measuring the position of a first structure (e.g., one of the structures 212, 220); then, moving the second sample a precisely known distance relative to the metrology subsystem 102 using a sample translation stage (e.g., an actuator, a motor, etc. configured to move the sample in an XY plane); and finally, imaging the other structure (e.g., structure 220 or structure 212). In another example, instead of moving the sample 204, the second registration measurement m2 is determined by deflecting light from the second interface target structure 212 to the second registration structure 220 via movement of one or more optical elements (e.g., mirrors, lenses, etc.) of the metrology subsystem 102. For example, the amount of movement (eg, rotation, translation) of a mirror configured to deflect illumination from a first field of view (FOV) to a second FOV may be used to calculate the relative distance between structures 212, 220 in each FOV.

[0059] In an embodiment, step 304 is performed before coupling the first sample 202 to the second sample 204 to form a coupled sample (e.g., before coupling step 306). In this regard, step 304 can be used to obtain a registration measurement m2 of the second interface target structure 212 before the second interface target structure 212 is obstructed by being covered by the first sample 202 during the coupling step.

[0060] In an embodiment, when the first sample 202 is coupled to the second sample 204 to form a coupled sample, the second registration structure 220 is configured to be unobstructed by the first sample 202. For example, the second registration structure 220 can be positioned in the scribe line area 222 so that the second registration structure 220 is not blocked by other elements when viewed along the negative Z direction. For example, the scribe line area 222 can be an area designated for cutting so that individual dies of the second sample 204 can be separated / cut. For example, unobstructed, visible, etc. can mean unobstructed to allow a third registration measurement (e.g., between the second registration structure 220 on the second sample 204 and a different structure (e.g., the first registration structure 208) Figure 2A Measurement m3).

[0061] In an embodiment, the second registration structure 220 is a target. For example, the second registration structure 220 may be an overlay target having a periodically repeating grating, such as, but not limited to, an AIM overlay target, a box-in-box (BiB) overlay target, etc. For example, the second registration structure 220 may be imaged using an optical metrology subsystem configured to image in the visible spectrum of light. In other examples, the second registration structure 220 may be a scanning electron microscope (SEM) target having a size (e.g., less than 4 um in width) and may be measured using a SEM metrology subsystem.

[0062] In step 306, return to reference Figure 2A , the first sample 202 is coupled to the second sample 204 (e.g., a carrier wafer) to form a coupled sample 200. In an embodiment, this coupling may be a temporary or permanent coupling. For example, the coupled sample 200 may be temporarily coupled (e.g., lightly clamped) for alignment purposes. For example, step 306 may be an intermediate coupling rather than a final bonding. In another example, the coupled sample 200 includes (or is) a bonding sample, such that the first sample 202 is fused to the second sample 204. For example, the coupling of step 306 may be fusion (i.e., bonding) using heat and pressure.

[0063] In an embodiment, step 306 is a temporary coupling for alignment purposes, and in a later optional bonding step, the first sample 202 is fused to the second sample 204 to form a bonded sample. For example, the optional bonding step may occur before or after obtaining the overlay measurement m4. One benefit of the optional bonding step occurring after obtaining the overlay measurement m4 is that the overlay measurement m4 can be used to adjust and reduce the overlay between the first sample 202 and the second sample 204. For example, the first sample can be lifted and replaced or slid to a new position based on the overlay measurement m4, thereby achieving tighter alignment tolerances.

[0064] In an embodiment, the direction of measurement (e.g., imaging) of the sample 106 (e.g., the first sample 202) may be reversed / inverted / flipped. In this regard, after the samples are mated and the interface between the samples cannot be imaged, the sample 106 may be imaged from both sides (e.g., first from the side / face to be joined and then from the opposite side (e.g., the back side). For example, before or during the coupling step 306, the first sample 202 may be flipped so that the first sample 202 may be imaged from the opposite side / direction. For example, the coupleable surface 214 may face the positive Z direction (e.g., the top surface 216 is mated to the coupleable surface 234) and then flipped to face the negative Z direction (e.g., the coupleable surface 214 is mated to the coupleable surface 234). For example, the coupleable surface 214 may be in the positive Z direction (e.g., the top surface 216 is mated to the coupleable surface 234). During manufacturing, the first metrology subsystem 102 may be turned upward and then flipped (upside down) to couple with the second sample 204. However, it should be noted that this example is illustrative and non-limiting and that the measurement direction of the sample 106 may be reversed / inverted in various ways. In another example, the rotation of the sample 106 may remain unchanged, but the metrology subsystem 102 may be rotated / inverted from the top side down (i.e., negative Z direction) to facing up under the sample. In another example, a different metrology subsystem 102 may be used that faces the opposite measurement direction from the first metrology subsystem 102, such that the sample is between the two metrology subsystems 102 and does not need to be rotated.

[0065] In step 308, reference Figure 2A , determining a third registration measurement m3 between the second registration structure 220 and the first registration structure 208 at least in part by imaging the first registration structure 208 through the top surface 216 of the first sample 202. In an embodiment, step 308 is performed after coupling the first sample 202 to the second sample 204 to form the coupled sample 200. For example, step 308 can be performed after coupling step 306. A non-limiting illustrative example of the third registration measurement is Figure 2A , 4B Marked as m3 in Figure 5B , 6B Marked as m3c.

[0066] In an embodiment, step 308 is performed via the metrology subsystem 102. For example, step 308 may be performed via one or more metrology subsystems 102 configured to operate in the infrared and / or visible spectral ranges of light. For example, step 308 may be performed via a single metrology subsystem 102 configured to operate in both the infrared and visible spectral ranges of light. In this regard, although not required, the front side (coupling side) measurements of the samples 202, 204 in steps 302 and 304 may be performed in visible light prior to coupling, and the "back side" measurements in step 308 may be performed in infrared in order to penetrate portions of the material and image the buried first registration structure 208. However, it should be noted that not all back side (post-coupling) measurements necessarily need to be performed in infrared, e.g. Figure 6BA measurement m3d of the first sample edge 230 may be performed with visible light.

[0067] In embodiments, first registration structure 208 may be in a variety of locations. For example, first registration structure 208 may be near top surface 216 such that the thickness and imageability of the material between first registration structure 208 and metrology subsystem 102 is sufficiently translucent to be imaged by metrology subsystem 102 for registration measurement purposes. For example, increased doping of a material may reduce the imageability of a given thickness of the material and may require first registration structure 208 to be closer to top surface 216 for imaging purposes. It should be noted that many other factors may affect the measurability of first registration structure 208, such as, but not limited to, opaque layers (e.g., opaque metal layers) and / or the density of structures (e.g., interconnects).

[0068] In another example, first registration structure 208 is positioned on a different layer than first interface target structure 206. For example, first registration structure 208 may be positioned closer to top surface 216 of first sample 202 than first interface target structure 206, which may be closer to coupleable surface 214.

[0069] In embodiments, the field of view may generally be of any size. For example, the field of view of the metrology subsystem 102 may be large enough to simultaneously image the second registration structure 220 and the first registration structure 208. For example, this field of view may be used to obtain a third registration measurement m3. For example, the second registration structure 220 and the first registration structure 208 may be simultaneously imaged in a single step to allow an absolute single registration measurement to be used to determine an overlay measurement between the first sample 202 and the second sample 204.

[0070] In step 310, reference Figure 2A ,based on Figure 2B The first registration measurement m1 in Figure 2C The second registration measurement m2 in Figure 2A The third registration measurement m3 in is used to obtain the superposition measurement m4 of the interface target 232.

[0071] As applicable to Figures 2A to 2C and Figures 4A to 4B By way of non-limiting example, the superposition measurement m4 may be calculated as follows:

[0072] m4=m2–(m1+m3) (Equation 1)

[0073] It may alternatively be written with reference to the element symbols as follows:

[0074] m4 = 206 to 212 = 220 to 212 - (206 to 208 + 208 to 220) (Equation 2)

[0075] It should be noted that the above examples are non-limiting, and any combination of measurements may generally be used to obtain a measurement, such as superposition measurement m4. For example, one or more of measurements m1, m2, and m3 may each be based on a mathematical combination of other superposition measurements (eg, measurements m1a, m1c, etc.).

[0076] According to one or more embodiments, it may be better understood from an alternative perspective. Figures 2A to 2C . Figure 4A Describe one or more embodiments of the present disclosure Figure 2A FIG. 2 is a top view of a first sample 202 . Figure 4B Describe one or more embodiments of the present disclosure Figure 2A 2. As shown, if the structure is not aligned in the Y direction, etc., the registration measurements m2, m3, etc. can be projected into one direction, such as the X direction. For example, the X projection from (0,0,0) to the XYZ coordinates (2,4,6) is 2 and the Y projection is 4.

[0077] It should be noted that Figure 2A to 2B and Figures 4A to 4B The size, location, type, quantity, arrangement and / or any other quality of the elements (e.g., structures, layers, samples, measurements) provided only for illustrative purposes and therein should not be construed as limiting. Rather, many other types of structures can be used to obtain registration measurements. For example, in some embodiments, structures in the scribe line region 506 of the first sample 202 providing the wafer can be used. In another example, a die edge can be used. In an additional example, an intermediate structure in an intermediate layer of the sample can be used. It should be noted that such examples are not necessarily mutually exclusive. For example, the method can utilize a combination of scribe line structures, die edges, first registration structures, and / or intermediate structures to obtain registration measurements that can be combined to obtain the superposition measurement m4.

[0078] Figures 5A to 5B An alternative example of using the first scribe line structure 508 associated with the first sample 202 to acquire the overlay measurement m4 is illustrated.

[0079] Figure 5A A side view 500 of a first sample 202 prior to being cut from a wafer according to one or more embodiments of the present disclosure is illustrated. In an embodiment, the first sample 202 may be a die cut from a providing wafer, as shown. The providing wafer may be, for example, a wafer used to produce die and / or chiplets, and the receiving wafer (i.e., a substrate wafer) may be a wafer configured to receive the die and / or chiplets during a coupling step. In an embodiment, the first sample 202 may be proximate to a first scribe line structure 508 that is not necessarily part of the first sample 202, such as any structure in a scribe line region 506 of the providing wafer. For example, the first scribe line structure 508 may be one or more overlay targets in a scribe line region 506 of the providing wafer.

[0080] In an embodiment, referring back to step 302, the first registration measure may be based on a single measurement or based on mathematically combining multiple measurements. For example, various registration measures m1a, m1b, m1c, etc. may be combined to calculate Figure 5A The first registered measurement m1f.

[0081] For example, various registration measurements m1a, m1b, m1c may be between first scribe structures 508 or stacks of first scribe structures 508 in various layers of the scribe area. For example, the first scribe structure 508 may be used throughout the manufacturing process of the first sample 202 (e.g., layer by layer) to keep track of the registration measurements m1a, m1b, m1c of the various structures 208, 504, 206 of the first sample 202. For example, the first scribe structure 508 may be in the intermediate layer 226 and unobstructed so that the first scribe structure 508 can be measured through multiple layers during the manufacturing process. Then, such measurements m1a, m1b, m1c may be combined to determine the first registration measurement m1f. For example, returning to reference Figure 2B , the first registration measurement m1 may alternatively be Figure 5A The first registration measurement m1f is mathematically based on the registration measurements m1a, m1b, m1c, m1d, etc. of the first scribe line structure 508 of the first sample 202. For example, the first registration measurement m1f may be mathematically equal to the registration measurement m1c minus the registration measurement m1a.

[0082] Figure 5B Description of one or more embodiments of the present disclosure Figure 5A 502 of the coupled sample of the first sample 202. In an embodiment, referring back to steps 302 to 310, the variations of the samples 202, 204 in steps 302 to 310 are shown. For example, the superposition measurement m4 may be calculated as follows:

[0083] m4=m2–m3a=m2–(m3c–m1f) (Equation 3)

[0084] Figures 6A to 6B An alternative example of using the first sample edge 230 associated with the first sample 202 to obtain the overlay measurement m4 is illustrated.

[0085] Fig. 6AA side view 600 of a first sample 202 having a first sample edge 230 (e.g., a die edge) according to one or more embodiments of the present disclosure is illustrated. In an embodiment, referring back to step 302, the first sample edge 230 may be used to determine a first registration measurement m1f. For example, the first registration measurement m1f may be based on registration measurements m1h, m1i, m1j, etc. of the first sample edge 230. For example, the first registration measurement m1f may be mathematically equal to the registration measurement m1h minus the registration measurement m1j.

[0086] Figure 6B Description of one or more embodiments of the present disclosure Fig. 6A A side view 602 of the coupled sample of the first sample 202. In an embodiment, referring back to steps 302 to 310, the variations of the samples 202, 204 in steps 302 to 310 are shown. For example, the superposition measurement m4 may be calculated as follows:

[0087] m4=m2–(m3d+m1j) (Equation 4)

[0088] Alternatively:

[0089] m4=m2–(m3c–m1g+m1j) (Equation 5)

[0090] Alternatively:

[0091] m4=m2–(m3c–m1f) (Equation 6)

[0092] Return to reference Figure 5A and 5B , illustrating an alternative example of using one or more intermediate structures 504 in one or more intermediate layers 226 to obtain a superposition measurement m4. In an embodiment, the intermediate structure 504 is generally located at any position within any layer. For example, the intermediate structure 504 is not necessarily in every intermediate layer, but may appear every few layers in some examples. For example, in a 20-layer first sample 202, layer 6 and layer 11 may each have one or more intermediate structures 504 buried therein. In an embodiment, the intermediate structure 504 can be used to keep track of the superposition throughout the first sample 202. In this regard, the registration and / or superposition measurement of the intermediate structure 504 can be used to determine the first registration measurement m1.

[0093] In an embodiment, the intermediate structure 504 is generally any type of structure, such as, but not limited to, a functional structure (such as a feature of a transistor or a logic gate) and / or a dedicated non-functional target. For example, the intermediate structure 504 may be an overlay target. In another example, the intermediate structure 504 may be a functional device feature. For example, if the intermediate structure 504 is a functional device feature, the space occupied by the intermediate structure can be more efficiently used to couple the electrical function of the sample and not wasted as a dedicated overlay target. In some examples, at least one of the one or more intermediate structures 504 is an overlay target. For example, some layers may not have functional structures that are easy to measure and may require at least one dedicated overlay target. For example, the intermediate structure 504 may be a SEM target configured to be imaged by the SEM metrology subsystem 102. For example, such a SEM target may be a target with a width and length less than 3um or 4um measured in a plane normal to the depth direction of the first sample. It should also be noted that in an embodiment, the first registration structure 208 may include such a SEM target of such size.

[0094] For purposes of this disclosure, "superposition" generally refers to the error between the intended pattern or structure placement and the actual pattern or structure placement. For example, superposition can refer to the error of the placement of the superimposed target or pattern of the device, such as lateral shift, rotation, magnification and / or a combination of such errors.

[0095] In an embodiment, various types of measurements may generally be based on the intermediate structure 504. For example, the types of measurements may include direct overlay measurements and registered overlay measurements between two or more structures. For example, a direct overlay measurement may represent a measurement between a structure in a layer directly above and adjacent to or overlapping it and a structure in an underlying layer. In this regard, the intermediate structure 504 may include functional structures (e.g., features of logic gates) in different layers that are just adjacent to or overlapping when viewed in the depth direction. In addition, the intermediate structure 504 may include overlapping or adjacent overlay targets that are typically used to obtain direct overlay measurements. Overlay registered measurements may represent measurements that are non-overlapping and separated by a distance (e.g., at Figure 5A The superposition of structures in different layers (distance greater than 80 microns (um) measured in the XY plane of the sample). For example, a superposition target spaced apart from a functional structure can be used to obtain a registered superposition measurement. It should be noted that any combination of intermediate structures can be utilized. For example, a measurement between two stacked patterns of structures (e.g., transistors) in layers 3 and 4 can be obtained and combined with a measurement between structures in layers 4 and 5. Such measurements can be tracked in some or all layers of the sample and used to keep track of structures at the interfaces of the sample. In this regard, intermediate structures 504 that are near each other and / or spaced apart from each other can be used to track the superposition between layers of the sample.

[0096] In an embodiment, at least one of the first registration measurement, the second registration measurement, or the third registration measurement is based on a die database-to-database measurement / verification. The die database-to-database measurement is generally obtained by comparing data (e.g., an image) collected from a sample with a rendered image (e.g., an image simulated based on sample design data used to manufacture the sample). For example, at least some methods of obtaining some types of die database-to-database measurements are disclosed in U.S. Patent No. 9,915,625, entitled "OPTICAL DIE TO DATABASE INSPECTION" filed on December 27, 2016, the entire text of which is incorporated herein by reference. For the purposes of this disclosure, the terms "database data", "design", "design data", etc. generally refer to the physical design (e.g., layout) of an IC and data derived from the physical design through complex simulations or simple geometric and Boolean operations. The physical design may be stored in a data structure (e.g., a graphic data stream (GDS) file, any other standard machine-readable file) and may be stored in a design database. A GDSII file is one of a class of files used to represent design layout data. Other examples of such files include GL 1 and OASIS files and proprietary file formats, such as RDF data proprietary to KLA-Tencor of Milpitas, California. In addition, an image of a reticle acquired by a reticle inspection system and / or derivatives thereof may be used as a "proxy" or "proxies" for a design. This reticle image or derivatives thereof may be used as a substitute for a design layout using a design in any of the embodiments described herein. The design may include any other design data or design data proxies described in U.S. Pat. No. 7,570,796, issued Aug. 4, 2009 to Zafar et al. and U.S. Pat. No. 7,676,077, issued Mar. 9, 2010 to Kulkarni et al., both of which are incorporated herein by reference in their entirety. In addition, the design data may be standard cell library data, integrated layout data, design data for one or more layers, derivatives of design data, and full or partial chip design data. The use of design data (e.g., stored on a database) and anchor points to determine measurements of a sample is disclosed in U.S. Pat. No. 10,267,746, issued on March 23, 2019, which is incorporated herein by reference in its entirety. In an embodiment, a die-to-database measurement may represent a measurement based on comparing a rendered design image of a sample with an optically acquired image of the sample. For example, a registration measurement may be based on a center-to-center (CoC) die-to-database (D:DB) measurement. In another example, a registration measurement of an edge (e.g., the first sample edge 230) may be based on comparing the center of an image of the edge with the rendered image to determine the center of the edge.For example, the registration measurement may be between this center of the edge and the center of another structure, such as a repeating intermediate transistor structure or any other structure. In some examples, the use of inter-die database measurements to determine the center of a structure is based on training a machine learning model based on a rendered design image (e.g., a fragment) and / or a corresponding optical image of the structure. In an embodiment, the benefit of using inter-die database measurements may allow for the elimination of the need to use a dedicated overlay target by allowing the distance vector of an edge in one structure to be measured relative to various other structures, such as edges, functional structures, etc. This may allow more active area of ​​the die to be used for functional structures.

[0097] In embodiments, the results (e.g., superposition measurement m4 and other measurements) may be used for any purpose in the sample manufacturing process (e.g., feedforward and / or feedback recipes). For example, the results may be used to correct the sample with a feedback recipe. Figure 2A The superposition of coupled samples 200 may be used to prevent the superposition of future coupled samples with a feed-forward recipe. For example, the results may be stored on a system external to the metrology subsystem 102 (e.g., an external controller and memory, such as an external server). Examples of such systems include systems configured to compile and reduce data (e.g., results) to generate relevant root cause and yield analysis information. For example, software on an external system (e.g., OVALiS software) may support on-product process optimization, diagnostics, monitoring, and control of lithography and other patterning steps important to IC manufacturing. In addition, the 5D Analyzer advanced data analysis and patterning control software may be used to provide an extensible, open architecture that accepts data from a wide range of metrology and process tools to enable advanced analysis, characterization, and real-time control of plant-wide process variations. In an embodiment, the results may be used for material excursion control or for any other use in a manufacturing process.

[0098] In an optional step (not shown), the method 300 or any other method further includes adjusting the inter-sample coupling recipe based on the superposition measurement m4. For example, the inter-sample coupling recipe may be a recipe stored in the memory 112 for determining alignment, permanent bonding (e.g., fusion), temporary coupling, or any other step in the coupling process. For example, adjusting the inter-sample coupling recipe may mean adjusting the X-direction position of the first sample 202 temporarily positioned on the second sample 204 based on the superposition measurement m4. In this regard, adjusting the X-direction position may mean moving the X-direction position by an amount equal to the superposition measurement m4 so that the superposition measurement m4 is reduced / eliminated. In this regard, the coupled samples can be more accurately aligned. In an embodiment, the inter-sample coupling recipe may include a final bonding recipe (e.g., a final bonding step for permanently fusing the samples 202, 204). Another example of adjusting the inter-sample coupling recipe may mean adjusting a parameter (e.g., heat, pressure, pre-bonding alignment) so that the future permanently bonded sample has a reduced superposition measurement.

[0099] In an optional step (not shown), the method 300 or any other method further includes adjusting the sample manufacturing recipe based on the overlay measurement m4. For example, adjusting the first sample manufacturing recipe may mean adjusting the deposition and / or etching offset of the layers of the first sample manufacturing recipe based on the first registration measurements m1a, m1b, m1c, etc., so that the overlay between the layers of the first sample 202 is corrected.

[0100] Reference again Figure 1 , and further detailed descriptions of embodiments of various components.

[0101] 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 maintained 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.

[0102] It should be noted herein that one or more components of the metering system 100 may be communicatively coupled to various other components of the metering 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 to other components via a wired (e.g., copper wire, fiber optic cable, etc.) or wireless connection (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 metering system 100 via any wired or wireless connection known in the art.

[0103] In an embodiment, the one or more processors 110 may include any one or more processing elements known in the art. In this regard, the one or more processors 110 may include any microprocessor-type device configured to execute software algorithms and / or instructions. In an 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 systems (e.g., networked computers) configured to execute a process configured to operate the metering system 100, as described throughout this disclosure. It should be recognized that the steps described in the present disclosure may be implemented 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 implemented on any one or more of the one or more processors 110. In general, the term "processor" may be broadly defined to cover any device having one or more processing elements that execute program instructions from the memory 112. In addition, different subsystems of the metering system 100 (e.g., the metering subsystem 102, the controller 108, the user interface, etc.) may include processors or logic elements suitable for implementing at least a portion of the steps described throughout this disclosure. Therefore, the above description should not be construed as limiting the present disclosure but is illustrative only.

[0104] 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 metering 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, read-only memory (ROM), random access memory (RAM), magnetic or optical storage (e.g., disk), tape, solid-state drive, etc. 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, etc. In another embodiment, the memory 112 may maintain program instructions for causing the one or more processors 110 to carry out the various steps described in the present disclosure.

[0105] In an embodiment, a 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, etc. In another embodiment, the user interface includes a display for displaying data of the metering 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.

[0106] All methods described herein may include storing the results of one or more steps of the method embodiment in a memory. The result may include any result 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 medium known in the art. After storing the result, the result may be accessed in the memory and used by anyone in the method or system embodiment described herein, formatted to 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 within a certain period of time. For example, the memory may be a random access memory (RAM) and the result may not be stored in the memory indefinitely.

[0107] It should be further considered that each of the above-described method embodiments may include any other steps of any other method described herein.In addition, each of the above-described method embodiments may be performed by any of the systems described herein.

[0108] Those skilled in the art will recognize that the components, operations, devices, objects, and accompanying discussions described herein are used as examples to make concepts clear and contemplate various configuration modifications. Therefore, as used herein, the specific examples and accompanying discussions set forth are intended to represent their more general categories. In general, the use of any specific example is intended to represent its category, and the non-inclusion of specific components, operations, devices, and objects should not be considered limiting.

[0109] As used herein, directional terms such as "top", "bottom", "above", "below", "up", "upward", "down", "below", "downward", "X direction", "Y direction", "Z direction", etc. 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.

[0110] 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 as appropriate to the context and / or application. For clarity, the various singular / plural arrangements are not explicitly set forth herein.

[0111] The subject matter described herein sometimes illustrates different components contained in or connected to other components. It should be understood that such depicted architectures are exemplary only, and in fact, many other architectures that implement the same function can be implemented. Conceptually, any arrangement of components that implement the same function is effectively "associated" so that the desired function is achieved. Therefore, regardless of the architecture or intermediate components, any two components combined to achieve a specific function herein can be considered to be "associated" with each other so that the desired function is achieved. Similarly, any two components so associated can also be considered to be "connected" or "coupled" to achieve the desired function, and any two components that can be so associated can be considered to be "coupleable" to each other to achieve the desired function. Specific examples that can be coupled 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.

[0112] 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 in particular in the appended claims (e.g., the body of the appended claims) are generally intended to be "open" terms (e.g., the term "comprising" should be interpreted as "including but not limited to", the term "having" should be interpreted as "having at least", the term "including" 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 will be clearly stated in the claims, and if there is no such statement, then there is no such intention. For example, as an aid to understanding, the following 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" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even if the same claim contains the introductory phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should generally be interpreted as intending "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, one skilled in the art will recognize that such recitation should generally be interpreted as intending at least the recited number (e.g., the bare recitation of "two recitations" without other modifiers generally means at least two recitations or two or more recitations). Furthermore, in those instances where a convention similar to “at least one of A, B, and C, etc.” is used, such construction is generally intended to be in the sense that is commonly understood by those skilled in the art (e.g., “a system having at least one of A, B, and C” would include, but is not 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 those instances where a convention similar to “at least one of A, B, or C, etc.” is used, such construction is generally intended to be in the sense that is commonly understood by those skilled in the art (e.g., “a system having at least one of A, B, or C” would include, but is not 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.). Those skilled in the art will further understand that almost any disjunctive term and / or phrase presenting two or more alternatives, whether in the specification, claims or drawings, should be understood to consider the possibility of including one of the terms, either of the two terms, or both terms. For example, the phrase "A or B" should be understood to include the possibility of "A" or "B" or "A and B".

[0113] It is believed that the present disclosure and many of its attendant advantages will be understood from the above description, and it should be understood that various changes may be made to the form, structure and arrangement of components without departing from the present disclosure or sacrificing all of its material advantages. The described form is for illustration only, and the following claims are intended to cover and encompass such changes. Furthermore, it should be understood that the invention is defined by the appended claims.

Claims

1. A metering system, comprising: a metrology subsystem configured to acquire a superposition measurement of an interface target on a coupled sample, wherein the coupled sample comprises the first sample coupled to a second sample at an interface between the first sample and a couplable face of the second sample according to a metrology recipe, wherein the interface target comprises a first interface target structure associated with the couplable face of the first sample and a second interface target structure associated with the couplable face of the second sample; and a controller communicatively coupled to the metering subsystem, the controller comprising one or more processors configured to execute program instructions such that the one or more processors: determining, on the first sample, a first registration measurement between the first interface target structure and a first registration structure positioned on a different layer than the first interface target structure prior to coupling with the second sample to form the coupled sample, wherein the first registration structure is configured to be measured by the metrology subsystem through a top surface of the first sample opposite the couplable surface of the first sample; determining, on the second sample prior to coupling with the first sample to form the coupled sample, a second registration measurement between the second interface target structure and a second registration structure, wherein the second registration structure is configured to be unobstructed by the first sample when the first sample is coupled to the second sample to form the coupled sample; after the first sample is coupled to the second sample, determining, on the coupled sample, a third registration measurement between the second registration structure on the second sample and the first registration structure on the first sample at least in part by measuring the first registration structure through the top surface of the first sample; and The superposition measurement of the interface object is obtained based on the first registration measurement, the second registration measurement, and the third registration measurement. 2 . The metrology system of claim 1 , wherein according to the metrology recipe, the first registration structure is positioned closer to the top surface of the first sample than the first interface target structure. 3 . The metrology system of claim 1 , wherein the second registration structure comprises a superimposed target in a scribe line region of the second sample.

4. The metering system of claim 1, wherein the program instructions are further configured to: The inter-sample coupling recipe is adjusted based on the superposition measurement. The metrology system of claim 4 , wherein the inter-sample coupling recipe comprises a final bonding recipe.

6. The metering system of claim 1, wherein the program instructions are further configured to: The sample manufacturing recipe is adjusted based on the overlay measurement.

7. The metrology system of claim 1, wherein the metrology subsystem is configured to operate in the visible spectrum range of light and the infrared spectrum range of light.

8. The metrology system of claim 1, wherein the determining the second registration measurement comprises measuring both the second interface target structure and the second registration structure in a visible spectrum of light via an optical metrology subsystem of the metrology subsystem.

9. The metrology system of claim 1, wherein the metrology subsystem is configured to operate in the infrared spectrum of light.

10. The metrology system of claim 1, wherein said measuring said first registration structure through said top surface of said first sample is performed via an infrared capable metrology subsystem of said metrology subsystem in an infrared spectrum range of light.

11. The metrology system of claim 1 , wherein a field of view of the metrology subsystem is large enough to simultaneously measure the second registration structure and the first registration structure.

12. The metrology system of claim 1 , wherein the determining the second registration measurement comprises moving one or more optical elements of the metrology subsystem to deflect illumination from a first field of view (FOV) to a second FOV, wherein the second registration measurement is based on the movement, wherein the second interface target structure is in the first FOV and the second registration structure is in the second FOV.

13. The metrology system of claim 1 , wherein said determining said second registration measurement comprises: measuring a position of a first structure; using a sample translation stage to move the second sample a known distance relative to the metrology subsystem; and imaging a second structure, wherein the first structure and the second structure are one of the second interface target structure or the second registration structure.

14. The metrology system of claim 1, wherein the determining the first registration measurement comprises performing measurements via a scanning electron beam (SEM) metrology subsystem of the metrology subsystem in one or more post-development inspection (ADI) steps of one or more layers of the first sample.

15. The metrology system of claim 1, wherein the first registration measurement is based on at least one of: one or more intermediate overlay registration measurements acquired during an intermediate manufacturing step of a layer of said first sample; or One or more intermediate direct overlay measurements taken during said intermediate manufacturing steps.

16. The metrology system of claim 15, wherein the one or more intermediate overlay registration measurements are based on a first scribe line structure.

17. The metrology system of claim 15, wherein the one or more intermediate overlay registration measurements are based on a first sample edge of the first sample.

18. The metrology system of claim 1, wherein the first sample comprises one or more intermediate structures buried at one or more intermediate layers within the first sample.

19. The metrology system of claim 18, wherein the one or more intermediate structures are at least one of superimposed objects or functional device features.

20. The metrology system of claim 1, wherein the first registration structure has a width and a length less than 3 microns measured in a plane normal to a depth direction of the first sample.

21. The metrology system of claim 1, wherein the coupling samples comprises joining samples such that the first sample fuses to the second sample.

22. The metrology system of claim 1, wherein at least one of the first registration measurement, the second registration measurement, or the third registration measurement is based on an inter-die database measurement.

23. A metrological method for obtaining a superposition measurement of a coupled sample, comprising: Prior to coupling a first sample to a second sample to form a coupled sample, determining, via a metrology subsystem, a first registration measurement between a first interface target structure of the first sample and a first registration structure, wherein the first registration structure is positioned on a different layer than the first interface target structure, wherein the first registration structure is configured to be measured by the metrology subsystem through a top surface of the first sample opposite a coupleable surface of the first sample, wherein the interface target comprises the first interface target structure associated with the coupleable surface of the first sample and a second interface target structure associated with the coupleable surface of the second sample; determining, via the metrology subsystem, a second registration measurement between the second interface target structure of the second sample and a second registration structure prior to coupling the first sample to the second sample to form the coupled sample, wherein the second registration structure is configured to be unobstructed by the first sample when the first sample is coupled to the second sample to form the coupled sample; coupling the first sample to the second sample to form the coupled sample; after the first sample is coupled to the second sample, determining, on the coupled sample, via the metrology subsystem, a third registration measurement between the second registration structure on the second sample and the first registration structure on the first sample at least in part by measuring the first registration structure through the top surface of the first sample; and The superposition measurement of the interface object is obtained based on the first registration measurement, the second registration measurement, and the third registration measurement.

24. The metrology method of claim 23, further comprising flipping the first sample prior to the coupling.

25. The metrology method of claim 23, wherein the first registration structure is positioned closer to the top surface of the first sample than the first interface target structure.

26. The metrology method of claim 23, wherein the second registration structure comprises a superimposed target in a scribe line region of the second sample.

27. The metrology method of claim 23, further comprising adjusting an inter-sample coupling recipe based on the overlay measurement.

28. The metrology method of claim 27, wherein the inter-sample coupling recipe comprises a final bonding recipe.

29. The metrology method of claim 23, further comprising adjusting a sample manufacturing recipe based on the overlay measurement.

30. The metrology method of claim 23, wherein the metrology subsystem is configured to operate in a visible spectrum of light and an infrared spectrum of light.

31. The metrology method of claim 23, wherein the determining the second registration measurement comprises measuring both the second interface target structure and the second registration structure in a visible spectrum of light via an optical metrology subsystem of the metrology subsystem.

32. The metrology method of claim 23, wherein the metrology subsystem is configured to operate in the infrared spectrum of light.

33. The metrology method of claim 23, wherein said measuring said first registration structure through said top surface of said first sample is performed via an infrared capable metrology subsystem of said metrology subsystem in an infrared spectrum range of light.

34. The metrology method of claim 23, wherein a field of view of the metrology subsystem is large enough to simultaneously measure the second registration structure and the first registration structure.

35. The metrology method of claim 23, wherein the determining the second registration measurement comprises moving one or more optical elements of the metrology subsystem to deflect illumination from a first field of view (FOV) to a second FOV, wherein the second registration measurement is based on the movement, wherein the second interface target structure is in the first FOV and the second registration structure is in the second FOV.

36. The metrology method of claim 23, wherein said determining said second registration measurement comprises: measuring a position of a first structure; using a sample translation stage to move the second sample a known distance relative to the metrology subsystem; and imaging a second structure, wherein the first structure and the second structure are one of the second interface target structure or the second registration structure.

37. The metrology method of claim 23, wherein the determining the first registration measurement comprises performing measurements via a scanning electron beam (SEM) metrology subsystem of the metrology subsystem in one or more post-development inspection (ADI) steps of one or more layers of the first sample.

38. The metrology method of claim 23, wherein the first registration measurement is based on: one or more intermediate overlay registration measurements acquired during an intermediate manufacturing step of a layer of said first sample; or One or more intermediate direct overlay measurements taken during said intermediate manufacturing steps.

39. The metrology method of claim 38, wherein the one or more intermediate overlay registration measurements are based on a first scribe line structure.

40. The metrology method of claim 38, wherein the one or more intermediate overlay registration measurements are based on a first sample edge of the first sample.

41. The metrology method of claim 23, wherein the first sample comprises one or more intermediate structures buried at one or more intermediate layers within the first sample.

42. The metrology method of claim 41, wherein the one or more intermediate structures are at least one of superimposed targets or functional device features.

43. The metrology method of claim 23, wherein the first registration structure has a width and a length measured in a plane normal to the depth direction of the first sample that is less than 3 microns.

44. The metrology method of claim 23, wherein the coupling comprises fusion of the first sample to the second sample.

45. The metrology method of claim 23, further comprising, after said coupling and said acquiring said superposition measurement, fusing said first sample to said second sample based on said superposition measurement.

46. ​​The metrology method of claim 23, wherein at least one of the first registration measurement, the second registration measurement, or the third registration measurement is based on an inter-die database measurement.

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