Measurement Systems for Packaging Applications

Abstract

Provided herein are methods and apparatus for detecting metrology data, for example, an apparatus that includes a substrate support configured to support a substrate and another substrate disposed on the substrate, an incoherent light source configured to transmit an illumination beam through the substrate and the another substrate, a set of optics configured to direct the illumination beam as it passes through the substrate and the another substrate, an actuator operatively coupled to the substrate support and configured to move the substrate and the another substrate back and forth in a scan pattern, and a sensor operatively coupled to and synchronized with the actuator and configured to receive the illumination beam from the set of optics to acquire subsurface images of the substrate and the another substrate.

Description

[Technical Field]

[0001] FIELD Embodiments of the present principles relate generally to semiconductor processing of semiconductor substrates. [Background technology]

[0002] During semiconductor manufacturing, mask alignment is typically achieved by using a system that steps to a location, acquires data from that location, and then moves to the next location. However, the inventors have observed that in packaging applications, thousands of locations may need to be processed on a single substrate, and step-and-repeat processes may not be fast enough to process a significant number of locations without a substantial impact on throughput.

[0003] For example, a constantly pressing issue in hybrid bonding and packaging applications is the need to ensure precise alignment of the bond pads of two connections. While, in absolute terms, the requirements are not as stringent as those required in conventional integrated chip (IC) manufacturing, this issue nevertheless poses a significant challenge because the bond pads are beneath the top silicon chip and therefore not visible in the visible light range. Infrared can be used to enable a metrology station to see down through the chip and expose alignment marks on the substrate to which the chip is bonded. To achieve reasonable throughput, alignment metrology for packaging applications requires high-speed techniques approaching thousands of measurements per hour.

[0004] Thus, the inventors have provided a method, apparatus, and system for alignment metrology that is conducive to packaging applications. Summary of the Invention

[0005]

[0009] Provided herein are methods and apparatus for alignment metrology conducive to packaging applications. For example, in at least some embodiments, an apparatus for detecting metrology data includes a substrate support configured to support a substrate and another substrate disposed on the substrate, an incoherent light source configured to transmit an illumination beam through the substrate and the another substrate, a set of optics configured to direct the illumination beam as it passes through the substrate and the another substrate, an actuator operably coupled to the substrate support and configured to move the substrate and the another substrate back and forth in a scan pattern, and a sensor operably coupled to and synchronized with the actuator and configured to receive the illumination beam from the set of optics to acquire subsurface images of the substrate and the another substrate.

[0006] According to at least some embodiments, a method for packaging applications includes supporting a substrate and another substrate disposed on the substrate on a substrate support, transmitting an illumination beam through the substrate and the other substrate, directing the illumination beam as it passes through the substrate and the other substrate, moving the substrate and the other substrate back and forth in a scanning pattern, and receiving the illumination beam to acquire subsurface images of the substrate and the other substrate.

[0007] According to at least some embodiments, a non-transitory computer-readable storage medium has stored thereon instructions that, when executed by a processor, perform a method for packaging applications, the method including supporting a substrate and another substrate disposed on the substrate on a substrate support, transmitting an illumination beam through the substrate and the other substrate, directing the illumination beam as it passes through the substrate and the other substrate, moving the substrate and the other substrate back and forth in a scanning pattern, and receiving the illumination beam to acquire subsurface images of the substrate and the other substrate.

[0008] Other and further embodiments of the present disclosure are described below.

[0009] Embodiments of the present disclosure, briefly summarized above and discussed in more detail below, can be understood by reference to exemplary embodiments thereof as illustrated in the accompanying drawings. The accompanying drawings, however, depict merely typical embodiments of the present disclosure and are therefore not to be considered limiting in scope, as the present disclosure may admit of other equally effective embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram of a chip being bonded to a substrate, in accordance with at least some embodiments of the present disclosure. [Figure 2] 1A-1D illustrate cross-sectional and top views of alignment of a chip bonded to a substrate, in accordance with at least some embodiments of the present disclosure. [Figure 3] 1A-1D illustrate cross-sectional and top views of alignment of a chip bonded to a substrate, in accordance with at least some embodiments of the present disclosure. [Figure 4] FIG. 1 is a diagram of a metrology system in accordance with at least some embodiments of the present disclosure. [Figure 5] FIG. 1 illustrates synchronization of sensors and actuators, in accordance with at least some embodiments of the present disclosure. [Figure 6] FIG. 1 is a diagram of a complete substrate scan pattern in accordance with at least some embodiments of the present disclosure. [Figure 7] FIG. 1 is a diagram of a metrology system in communication with a hybrid bonder to enable alignment feedback, in accordance with at least some embodiments of the present disclosure. [Figure 8] 1 is a flow diagram of a method for packaging applications according to at least some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] For ease of understanding, identical reference numbers have been used, where possible, to designate identical elements common to the figures. The figures are not drawn to scale and may be simplified for clarity. Elements and features of one embodiment may be beneficially incorporated in other embodiments without further elaboration.

[0012]

[0003] Embodiments of a method, apparatus, and system for alignment metrology useful for packaging applications are provided herein. For example, the apparatus includes a substrate support configured to support a substrate (e.g., a transparent substrate) and another substrate (e.g., a die / coupon / wafer) disposed on the substrate; an incoherent light source configured to transmit an illumination beam through the substrate and the other substrate; a set of optics configured to direct the illumination beam as it passes through the substrate and the other substrate; an actuator operably coupled to the substrate support and configured to move the substrate and the other substrate back and forth in a scanning pattern; and a sensor operably coupled to the actuator, synchronized with the actuator, and configured to receive the illumination beam from the set of optics to acquire subsurface images of the substrate and the other substrate. The methods and apparatus described herein overcome the previously described shortcomings associated with conventional methods and apparatuses, creating a high-speed scanning apparatus that allows metrology data, such as bonding alignment data, to be acquired quickly and efficiently without slowing down the packaging process and substantially affecting yield.

[0013] 1 is a diagram 100 of a first chip 102 being bonded to a substrate 118, according to at least some embodiments of the present disclosure. The first chip 102 can originate from a component substrate (not shown). During hybrid bonding, the first chip 102 can be picked up off the component substrate and flipped 108 upside down so that the top surface 104 of the first chip 102, bearing a first alignment mark 120 (or fiducial), becomes the bottom surface or chip bonding surface that is bonded to the top surface 106 or substrate bonding surface of the substrate 118. The top surface 106 of the substrate 118 can have a second alignment mark 122 that is used to align with the first alignment mark 120 of the first chip 102 during bonding 110.

[0014] 2 illustrates a cross-sectional view 200B and a top view 200A of aligned fiducial marks, as well as a top view 200C of a first chip 102 bonded to a substrate 118, according to at least some embodiments of the present disclosure. In the non-limiting example illustrated in FIGS. 1 and 2, the first alignment mark 120 of the first chip 102 is a circle, and the second alignment mark 122 of the substrate 118 is a ring. In this example, proper alignment is when the circle of the first alignment mark 120 is centered within the ring of the second alignment mark 122 of the substrate 118, as shown in top views 200A and 200C. When the first chip 102 is bonded to the substrate 118, the first alignment mark 120 and the second alignment mark 122 are essentially coplanar along plane 128, as shown in cross-sectional view 200B.

[0015] To determine whether proper alignment between the first chip 102 and the substrate 118 has been achieved after bonding, an illumination beam 124 is set to pass through the substrate 118, the bonding surface of the first chip 102 near the top surface 106 at a plane 128, and the first chip 102 (e.g., at a depth 130). The illumination beam 124 is then captured by a detector (not shown, see FIG. 4 ), which processes a set of image data from the illumination beam 124. The detector or associated image analyzer (e.g., alignment correlator 446 in FIG. 4 ) compares the image data of the first alignment mark 120 on the first chip 102 with the second alignment mark 122 on the substrate 118 to determine whether an alignment error has occurred. The image data may also be compared to previous image / alignment error data to determine the overall alignment error, including rotational error (angular alignment error caused by rotational skewing of the bonded chip relative to the substrate, e.g., see top view 300C in FIG. 3 ).

[0016] Some packaging processes have stacked chips that require multi-planar subsurface imaging, which presents unique challenges. For example, the system must be able to image at multiple depths or focal points as needed. In some embodiments, an optional second chip 202 may be bonded to the first chip 102, as shown in FIG. 2. The fourth alignment mark 222 of the optional second chip 202 is used to align with the third alignment mark 220 of the first chip 102 during bonding 110. In the non-limiting example shown in FIG. 2, the third alignment mark 220 of the optional second chip 202 is a circle, and the fourth alignment mark 222 of the first chip 102 is a ring. In this example, proper alignment is similar to top view 200A, where the circle of the third alignment mark 220 is centered within the ring of the fourth alignment mark 222 of the first chip, as shown in top view 200C. When the optional second chip 202 is bonded to the first chip 102, the third alignment mark 220 and the fourth alignment mark 222 are essentially coplanar at the interface 228 of the bonding surfaces of the chips, as shown in cross-sectional view 200B.

[0017] To determine whether proper alignment between the first chip 102 and the second chip 202 has been achieved after bonding, the illumination beam 124 is set to pass through the optional second chip 202 and then captured by a detector (not shown, see FIG. 4 ) that processes a set of image data from the illumination beam 124. The detector or associated image analyzer (e.g., alignment correlator 446 of FIG. 4 ) compares the image data of the third alignment mark 220 of the optional second chip 202 with the fourth alignment mark 222 of the first chip 102 to determine whether an alignment error has occurred. The image data may also be compared to previous image / alignment error data to determine the overall alignment error, including rotational error (angular alignment error caused by rotational skewing of the bonded chip relative to the substrate, e.g., see top view 300C of FIG. 3 ).

[0018] In more complex packaging processes, bonded single chips and bonded stacked chips may require multi-planar subsurface imaging to acquire fiducial alignment images because the fiducial alignment pairs may be located in different planes. In cross-sectional view 300A of FIG. 3, a first chip 304 is bonded to a substrate 302. The substrate 302 has fiducials, or a first set of alignment marks 308, on a first surface 310. The first chip 304 has a second set of alignment marks 312 on a second surface 314 that are intended to align the first chip 304 to the substrate 302. To determine whether proper alignment between the first chip 304 and the substrate 302 has been achieved after bonding, the illumination beam 124 is set to pass through the substrate 302 near the first surface 310 and the first chip 304 (e.g., at a first depth 318). The illumination beam 124 is then captured by a detector (not shown, see FIG. 4), which processes a first set of image data from the illumination beam 124. The detector or associated image analyzer (e.g., alignment correlator 446 of FIG. 4) compares the sets of image data and determines whether an alignment error has occurred. The image data may also be compared with the image / alignment error data to determine the overall alignment error, including rotational error (angular alignment error caused by rotational skewing of the bonded chip).

[0019] In the cross-sectional view 300B of FIG. 3, a second chip 306 is bonded to the first chip 304. The second chip 306 has a third set of alignment marks 326 on its third surface 330, which are intended to align the second chip 306 to the first chip 304. The third set of alignment marks 326 align with a fourth set of alignment marks 328 on the second surface 314 of the first chip 304, and with one or more of the marks in the second set of alignment marks 312 on the second surface 314 of the first chip 304. When alignment overlap occurs in multiple bonding stacks, previous image data can be used to compare with newly acquired image data at different depths. Image data from each of the surfaces of the substrate 302, the first chip 304, and the second chip 306 can be compared without requiring repetition of the illumination beam at different depth levels (foci).

[0020] In the top view 300C of FIG. 3 , a substrate 302 is shown with a first chip 304 bonded to the substrate 302 and a second chip 306 bonded to the first chip 304. A third set of alignment marks 326 is visible on a third surface 330 of the second chip 306. A portion of a second set of alignment marks 312 is visible on a second surface 314 of the first chip 304. As an example, a desired orientation line 334 of the second chip 306 is used to compare with an actual (skewed) orientation line 336 having an error angle 338. The error angle 338 indicates a positive or negative rotation from the desired orientation. Thus, both alignment and orientation errors can be determined from image data obtained from the alignment marks. The illumination source must be able to penetrate the silicon material while simultaneously being fast-focus adjustable to allow multiple focal spots at different depths. In some situations, thousands of locations on the substrate 302 need to be scanned in time. Despite the challenges presented, the inventors have overcome the obstacles to create a high-speed scanning device that allows metrology data, such as bonding alignment data, to be acquired quickly and efficiently without slowing the packaging process and without substantially impacting yield.

[0021] 4 is a diagram of a metrology system 400 in accordance with at least some embodiments of the present disclosure. For example, metrology system 400 includes three sub-modules: a detection sub-module, an illumination sub-module, and a motion sub-module. Metrology system 400 is operable in a trans-illumination mode in operation 405 and an epi-illumination mode in operation 407.

[0022] For example, in the transmitted illumination mode of operation 405, the detection sub-module includes an optical system set including at least one of a high-magnification microscope 402 (e.g., ranging from about 10x to about 100x magnification) including an autofocus lens 404 (e.g., beam-forming optics), a single resolution lens 410 or tube lens 406, and a multi-stage SWIR (short-wave infrared) TDI (time delay integration) sensor 408 (e.g., linear sensor, camera). In at least some embodiments, the autofocus lens 404 can include a high-speed electrically tunable lens or an acousto-optically modulated lens (e.g., kilohertz-rate, laser-based active focusing module, or image contrast-based passive autofocus module) capable of focusing at multiple depths. In at least some embodiments, the single resolution lens 410 can be a high-resolution lens.

[0023] Given the line rates at which the multi-stage SWIR TDI sensor 408 can operate (approximately 10 Hz to approximately 100 kHz, e.g., 10 Hz to 900 kHz), the resulting short exposure time can result in an insufficient amount of light at the sample (e.g., substrate (wafer) coupon), rendering the multi-stage SWIR TDI sensor 408 light-starved. Therefore, a key challenge is managing the tradeoff between illumination light intensity, etendue, and coherence. Compared to known methods and apparatus that use lasers for the illumination beam, the methods and apparatus described herein use an incoherent light source 412 (e.g., an LED or alternative light source), which eliminates the need for speckle bust. For example, light in the SWIR wavelength range can pass completely through the substrate 401 (silicon, germanium, etc. wafer) coupon (403) package and, therefore, can be used in a transmitted illumination mode of operation 405. In the transmitted illumination mode of operation 405, the incoherent light source 412 is positioned adjacent to the underside / bottom side of the substrate (wafer), significantly improving the efficiency of the light path from the incoherent light source 412 to the sample (e.g., the area being scanned on the substrate). For example, in the transmitted illumination mode of operation 405, the substrate 401 (wafer) can rest on a transparent surface 421, which is disposed on a substrate support 419 and configured to support the substrate 401, and an XYZR stage 414 (e.g., an actuator or scanner) can be operably coupled to the incoherent light source 412 (e.g., to enable underside access over the substrate 401 (e.g., the entire substrate)). For example, in at least some embodiments, the incoherent light source 412 and the XYZR stage 414 can be disposed on (positioned on) the substrate support 419 directly below the transparent surface 421 on which the substrate 401 can be positioned. In at least some embodiments, the incoherent light source 412 can be positioned below the XYZR stage 414. Alternatively, the incoherent light source 412 can be positioned above the XYZR stage 414.During operation, the incoherent light source 412 and the XYZR stage 414 remain relatively stationary, but the XYZR stage 414 moves the transparent surface 421 of the substrate support 419 along the x and y directions. In at least some embodiments, the XYZR stage 414 can also move the transparent surface 421 of the substrate support 419 along the z direction and rotate the substrate support 419 (e.g., in the r direction).

[0024] However, in advanced packaging involving stacking and bonding multiple coupons onto the substrate 401 (e.g., in memory applications), opaque features such as copper pads and wiring from lower-level coupons can block the transmission of light delivered via the trans-illumination mode of operation. Therefore, in at least some embodiments, the epi-illumination mode of operation 407 can be used to deliver light directly to the topside of multiple coupons and / or substrates. In such embodiments, the incoherent light source 412 can be positioned between the high-magnification microscope 402 and the multi-stage SWIR TDI sensor 408, and one or more optical components 416 (e.g., at least one of a beam splitter, a reflector, a polarizer, etc., which may be components of the high-magnification microscope 402) can be used to direct the illumination beam from the incoherent light source 412 to the topside of the multiple coupons and / or substrates. In at least some embodiments, the incoherent light source 412 can be positioned on a platform (not shown) adjacent to the substrate support 419. Alternatively, the incoherent light source 412 can be positioned on an interior wall of the processing chamber. The reflected illumination beam may reflect off multiple coupons and / or substrates and return to the multi-stage SWIR TDI sensor 408 via one or more optical components 416 .

[0025] Depending on the system configuration, more than 50-75% of the light transmitted from the incoherent light source 412 may be lost when coupling the illumination sub-module into the rest of the optical system. In at least some embodiments, a single sufficiently bright incoherent light source in the SWIR range can minimize the level of light loss. However, in other embodiments, a single light source may not be bright enough. In the latter case, a multispectral incoherent light source (e.g., a light source with a wide range of optical wavelengths) containing many spectral channels that meet the quantum efficiency (QE) band of the multi-stage SWIR TDI sensor may be used to further address the lack of light intensity. Thus, in at least some embodiments, multiple incoherent and / or multispectral incoherent light sources can be used simultaneously to improve throughput by uniformly using different wavelengths along the entire sample (e.g., substrate). For example, in such embodiments, multiple incoherent and / or multispectral incoherent light sources can create multiple corresponding illumination beams that travel a path similar to illumination beam 124, except that they are directed along a substrate, such as a stacked chip. For example, in at least some embodiments, such as when a multi-stage SWIR TDI sensor can detect over a certain wavelength range (e.g., about 1300 nm to about 1700 nm) and the light source can emit over a very wide wavelength range (e.g., about 1300 nm to about 1700 nm), but the light source is not bright enough, the light source can be replaced with a series of narrower band light sources that can collectively deliver more power to the sample. For example, if light source 1 can emit from about 1410 nm to about 1430 nm but is not bright enough, then light source 2 can be added in another wavelength band (e.g., to emit from about 1510 nm to about 1530 nm), light source 3 can be added in another wavelength band (e.g., to emit from about 1630 nm to about 1650 nm), and so on, to add the needed brightness.

[0026] The motion sub-module consists of an XYZR stage 414 that can be synchronized (indicated by synchronization arrows) with the readout rate of the multi-stage SWIR TDI sensor 408. The XYZR stage 414 can move the incoherent light source 412 along multiple paths. For example, in at least some embodiments, the XYZR stage 414 can move the incoherent light source 412 along the Y direction at a speed such that a particular target (an area along a substrate (wafer) coupon) is exposed multiple times by each successive stage (e.g., line) of the multi-stage SWIR TDI sensor 408. Thus, in at least some embodiments, by averaging each exposure (either in analog mode with charge accumulation after readout of the multi-stage SWIR TDI sensor 408, or digitally), the substrate 401 can be continuously scanned at high speed without sacrificing signal-to-noise ratio (SNR). 5 and 6 show how mapping of an entire substrate (wafer) can be achieved in a relatively serpentine manner by scanning multiple strips (e.g., 1, 2, 3, 4, 5, 6, ..., nth) across the Y direction and stepping across the X direction. For example, an XYZR stage 414 is configured to move a substrate support including a substrate with a sample thereon. The multi-stage SWIR TDI sensor 408 and the incoherent light source 412 remain stationary. In at least some embodiments, the multi-stage SWIR TDI sensor 408 can be configured with 128 stages of integration, e.g., N=128, and 1024 columns, e.g., M=1024.

[0027] Alternatively or additionally, if coverage of the entire substrate is not required, the selected targets may be pre-defined prior to image acquisition and the stage may be directed only to specific locations.

[0028] Image data is formed using the illumination beam 124 while illuminating a target location on the substrate. For example, the illumination beam 124 is directed to and received by the multi-stage SWIR TDI sensor 408. The multi-stage SWIR TDI sensor 408 receives the illumination beam 124 and generates an image. For example, the illumination beam 124 can operate in conjunction with a store 438, which stores the image in memory and can later be recalled for alignment comparison, and / or an alignment correlator 446, which receives multiple images from the multi-stage SWIR TDI sensor 408 and uses an image overlay process to determine alignment error locations and values ​​(e.g., alignment shift, alignment rotation error, etc.). In some embodiments, the images are created by the multi-stage SWIR TDI sensor 408 by taking samples beyond the Nyquist number per point spread function (PSF) to render alignment statistics independent of the exact location of the target. Thus, once assembled, the image of the target is identical (in terms of the information it conveys) to an acquired non-scanned image (such as an image taken with a digital camera), and therefore the algorithmic strategies utilized to perform measurements on the image (such as by alignment correlator 446) can use similar algorithmic strategies used with static images.

[0029] The controller 420 enables data collection and feedback from each device in the measurement system 400, which can be used to optimize the performance of the measurement system 400 as well as the control of the system devices (e.g., scan pattern, scan control, scan location, etc.). The controller 420 typically includes a CPU 422 (central processing unit), memory 424 (non-transitory computer-readable storage medium), and support circuits 426. The CPU 422 can be any form of general-purpose computer processor that can be used in an industrial environment. The support circuits 426 are conventionally coupled to the CPU 422 and can include cache, clock circuits, input / output subsystems, power supplies, etc. Software routines, such as methods for controlling the measurement system 400 as described above, can be stored in the memory 424 and, when executed by the CPU 422, can transform the CPU 422 into a special-purpose computer (controller 420). The software routines may also be stored and / or executed by a second controller (not shown) located remotely from the measurement system 400.

[0030] In at least some embodiments, the controller 420 can be in operative communication with the incoherent light source 412 to change the illumination wavelength and / or power, etc., the high-magnification microscope 402 to shape the illumination beam 124, the XYZR stage 414 to increase or decrease the scan speed and / or scan width, and the multi-stage SWIR TDI sensor 408 to generate high-resolution images by changing the algorithm type, etc.

[0031] Precise pixel positioning in the acquired image is particularly important in hybrid bonding applications. Therefore, the controller 420 enables control of an incoherent light source to simultaneously illuminate the entire field of view and controls the XYZR stage 414 to move the substrate from one end of the field of view to the other. The controller 420 can also operatively communicate with the store 438 and / or the alignment correlator 446 to further enhance the metrology data collection process. The controller 420 can also operatively communicate with actuators (not shown) of the substrate support (not shown) to enable movement in the X and Y directions to create a scan swath. The controller 420 can also change the substrate / chip scan location as needed by commanding the actuators to move to various locations. The controller 420 can also coordinate and communicate with the XYZR stage 414 and actuators to enable desired scan patterns, etc. Those skilled in the art will appreciate that other auxiliary devices (e.g., additional optics, power supplies, etc.) may be used in conjunction with the metrology system 400, and the controller 420 may also communicate with the auxiliary devices.

[0032] Data from the metrology system 400 can be analyzed in two stages. For example, in the first stage, the raw data can be converted into overlay misalignment values, which can then be related to other parameters within the bonding tool. For example, the raw data generated by the metrology system 400 can be configured to take the form of strips along the XY plane and imaged as described above. The X range of a single strip is determined by the length of the multi-stage SWIR TDI sensor 408 and the magnification of the optical system (e.g., the illumination submodule). The Y range of the strip is determined by the range of the stage scan along the Y direction. Detection of overlay targets within the strips can be performed via commonly used machine vision techniques (e.g., fiducial alignment and image registration, as described above), allowing users to quickly quantify misalignment between the substrate (wafer) and the coupon at specific locations on the substrate (wafer). Then, in the second stage, the extracted overlay measurements can be related to various process tool parameters. For example, poor parameter selection in an upstream wet cleaning step can manifest as greater misalignment of the coupon toward the edge. As another example, location-dependent misalignment may be correlated with the pressure profile used during the bonding step. Machine learning may be used in conjunction with integrated packaging tools with on-board metrology capabilities that can establish parameter relationships.

[0033] The metrology system 400 may be used in conjunction with a hybrid bonder 702 to improve the hybrid bonding alignment process, as shown in diagram 700 of FIG. 7 . The hybrid bonder 702 is generally controlled by a controller 720. The controller 720 can be used to enable data collection and feedback / feedforward from the controller 420 of the metrology system 400 to optimize the performance of the hybrid bonder 702. The controller 720 typically includes a CPU 722 (central processing unit), memory 724, and support circuits 726. The CPU 722 can be any form of general-purpose computer processor that can be used in an industrial environment. The support circuits 726 are conventionally coupled to the CPU 722 and can include cache, clock circuits, input / output subsystems, power supplies, etc. Software routines, such as methods for controlling the alignment of bonding substrates and / or chips, can be stored in the memory 724 and, when executed by the CPU 722, can transform the CPU 722 into a special-purpose computer (e.g., the controller 720). The software routines may also be stored and / or executed by a fourth controller (not shown) located remotely from the hybrid bonder 702 .

[0034] In some embodiments, the metrology system 400 communicates directly with the controller 720 to relay alignment information to the hybrid bonder 702 so that subsequent bonding processes can improve alignment errors. Feedback / feedforward from the metrology system 400 can be real-time or at scheduled intervals. In some embodiments, the alignment correlator 446 of the metrology system 400 can transmit actual alignment error data and values, such as, but not limited to, alignment offsets per fiducial and / or angle rotation error values ​​for a given type of chip and / or location of one or more chips. To facilitate enhanced value of the alignment information, the metrology system 400 can incorporate machine learning to augment image data processing in, for example, but not limited to, the multi-stage SWIR TDI sensor 408, the alignment correlator 446, and / or the controller 420. In some embodiments, the alignment image data processor 704 may be used in conjunction with machine learning to interpret alignment information and / or data information from the metrology system 400 to correlate alignment errors with changes needed in the hybrid bonder 702 to reduce or eliminate subsequent bonding alignment errors. Thus, for example, but not limited to, machine learning can consider alignment shift data, alignment rotation errors, etc. to determine, for example, but not limited to, the ability of the hybrid bonder 702 to reduce / eliminate errors. For example, machine learning can consider the applied pressure of the hybrid bonder, the amount of vacuum used to pick up the chip, and / or the tolerances of the mechanical device used to position the chip on the substrate, etc., to reduce alignment errors by the hybrid bonder.

[0035] 8 is a flow diagram of a method 800 for packaging applications according to at least some embodiments of the present disclosure. For illustrative purposes, the method 800, executed under the control of the controller 420, will be described in terms of use by the metrology system 400.

[0036] For example, at 802, the method 800 includes supporting a substrate and another substrate disposed on the substrate on a substrate support. For example, the substrate 401 and at least one of a coupon, wafer, or die supported on the substrate may be supported on a transparent surface 421 of the substrate support 419.

[0037] Next, at 804, method 800 includes transmitting the illumination beam through the substrate and another substrate. For example, as described above, incoherent light source 412 can be configured to transmit illumination beam 124 through substrate 401 and another substrate. In at least some embodiments, such as when incoherent light source 412 is positioned directly below transparent surface 421 (transmitted illumination mode of operation 405), transparent surface 421 can be configured to transmit the illumination beam from a bottom side of substrate 401 through substrate 401 and another substrate. Alternatively, in at least some embodiments, such as when incoherent light source 412 is positioned between the set of optics and multi-stage SWIR TDI sensor 408, incoherent light source 412 can be configured to transmit light directly to an upper side of substrate 401 and another substrate (epi-illumination mode of operation 407).

[0038] Next, at 806, the method 800 includes directing the illumination beam as it passes through the substrate and another substrate. For example, a set of optical systems including at least one of a high magnification microscope 402, an autofocus lens 404, a single resolution lens 410, or a tube lens 406 can be configured to direct the illumination beam as it passes through the substrate 401 and another substrate.

[0039] Next, at 808, the method 800 includes moving the substrate and the other substrate back and forth in a scanning pattern, and at 810, the method 800 includes receiving an illumination beam to acquire a subsurface image of the substrate and the other substrate.

[0040] For example, at 808, the scanning process can include the XYZR stage 414 performing a relatively serpentine motion. For example, in at least some embodiments, the Y stage of the XYZR stage 414 moves the substrate along the y direction of the multi-stage SWIR TDI sensor 408 (e.g., N stages), while the multi-stage SWIR TDI sensor 408 synchronously shifts the image of the sample. The Y stage of the XYZR stage 414 continues to move the substrate along the y direction until an entire row of the substrate has been scanned (see column 1 in FIG. 6 ). Next, the X stage of the XYZR stage 414 is advanced by Mx pixels (see columns 1-2 in FIG. 6 , where x can be on the order of about 10 pixels). Next, the Y stage will again scan the sample along a new row, but this time in the reverse direction (see column 2 in FIG. 6 ). The inventors have found that by repeating the scanning process, a user can achieve a complete scan of the substrate in a relatively serpentine manner.

[0041] In at least some embodiments, such as when a user knows the general locations of the fiducial marks (see, e.g., FIGS. 2 and 3), covering the entire substrate may not be necessary. For example, at the end of a given swath (e.g., column), the X-stage may be stepped to the expected (or known) x-coordinate location of the nearest fiducial mark before the y-stage re-engages as described above (e.g., skipping one or more x-coordinate locations before the y-stage re-engages). Thus, by avoiding areas without fiducial marks, a user can achieve faster throughput.

[0042] Embodiments according to the present principles may be implemented in hardware, firmware, software, or any combination thereof. Embodiments may also be implemented as instructions stored using one or more computer-readable media, which may be read and executed by one or more processors. A computer-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing platform, or a "virtual machine" running on one or more computing platforms). For example, a computer-readable medium may include any suitable form of volatile or non-volatile memory. In some embodiments, a computer-readable medium may include a non-transitory computer-readable medium.

[0043] While the forgoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof.

Claims

1. 1. An apparatus for detecting metrology data, comprising: a substrate support configured to support a substrate and another substrate disposed above the substrate; an incoherent light source configured to transmit an illumination beam through the substrate and the further substrate; a set of optics configured to direct the illumination beam through the substrate and the further substrate; an actuator operably coupled to the substrate support and configured to move the substrate and the further substrate back and forth in a scanning pattern; a sensor operatively coupled to the actuator, synchronized with the actuator, and configured to receive the illumination beam from the set of optical systems to acquire subsurface images of the substrate and the another substrate; 1. An apparatus comprising:

2. The apparatus of claim 1 , wherein the other substrate is at least one of a coupon, a wafer, or a die.

3. The apparatus of claim 1 , wherein the incoherent light source is an LED configured to produce light in the short wave infrared (SWIR) wavelength range.

4. The apparatus of claim 1 , wherein the optical system set includes at least one of a high-magnification microscope, an autofocus lens, a single resolution lens, or a tube lens.

5. 5. The apparatus of claim 1, wherein the autofocus lens comprises an electrically adjustable lens or an acousto-optical modulating lens configured to focus at multiple depths through the substrate and the further substrate.

6. The apparatus of claim 1 , wherein the optical system set is configured to provide a magnification of about 10× to about 100×.

7. The apparatus of claim 1 , wherein the sensor is a multi-stage SWIR time delay integration (TDI) sensor.

8. The apparatus of claim 1 , wherein the actuator is configured to move the substrate and the further substrate in x and y directions to form a relatively serpentine pattern.

9. The apparatus of claim 1 , wherein the incoherent light source and the actuator are disposed on the substrate support.

10. 10. The apparatus of claim 1, further comprising a transparent surface disposed on the substrate support and movable relative to the substrate support, the incoherent light source being positioned directly below the transparent surface and configured to deliver the illumination beam from a bottom side of the substrate.

11. The apparatus of claim 1 , wherein the incoherent light source is positioned between the set of optics and the sensor to deliver light directly onto an upper side of the substrate and the another substrate.

12. The apparatus of any of claims 1 to 4, 6 to 9, or 11, further comprising at least one of a beam splitter, a reflector, or a polarizer.

13. 1. A method for packaging applications comprising: supporting a substrate and another substrate disposed above the substrate on a substrate support; transmitting an illumination beam through the substrate and the further substrate; directing the illumination beam through the substrate and the further substrate; moving the substrate and the further substrate back and forth in a scanning pattern; receiving the illumination beam to obtain subsurface images of the substrate and the another substrate; A method comprising:

14. The method of claim 13 , wherein the other substrate is at least one of a coupon, a wafer, or a die.

15. The method of claim 13 , wherein transmitting the illumination beam is performed using an LED configured to produce light in the short wave infrared (SWIR) wavelength range.

16. 14. The method of claim 13, wherein directing the illumination beam is performed using a set of optics including at least one of a high magnification microscope, an autofocus lens, a single resolution lens, or a tube lens.

17. 17. The method of any of claims 13 to 16, wherein the autofocus lens comprises an electrically tunable lens or an acousto-optical modulating lens configured to focus at multiple depths through the substrate and the further substrate.

18. The method of any of claims 13 to 16, wherein the optical system set is configured to provide a magnification of about 10x to about 100x.

19. The method according to any of claims 13 to 16, wherein receiving the illumination beam is performed using a multi-stage SWIR time delay integration (TDI) sensor.

20. A non-transitory computer-readable storage medium having stored thereon instructions that, when executed by a processor, perform a method for packaging applications, the method comprising: supporting a substrate and another substrate disposed above the substrate on a substrate support; transmitting an illumination beam through the substrate and the further substrate; directing the illumination beam through the substrate and the further substrate; moving the substrate and the further substrate back and forth in a scanning pattern; receiving the illumination beam to obtain subsurface images of the substrate and the another substrate; 1. A non-transitory computer-readable storage medium comprising:

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