Target position determination for a component at a bond location of a substrate using interferometry

Abstract

In a die bonder, an alignment mark that is on a component or on a substrate is placed within a sensitivity range of an interferometer. A phase of at least one diffracted beam from an illumination of the alignment mark is determined using the interferometer and used to determine a position of the alignment mark relative to the interferometer. Based on the position of the alignment mark relative to the interferometer, a correction vector is determined and applied to a nominal target position for the component to determine a corrected target position for the component. The corrected target position is then used to bond the component to the substrate. By using the interferometer, the alignment mark can be made very small. Furthermore, the interferometer enables a determination of a very accurate correction vector.

Description

TARGET POSITION DETERMINATION FOR A COMPONENT AT A BOND LOCATION OF A SUBSTRATE USING INTERFEROMETRYPRIORITY

[0001] This application claims priority to U.S. provisional application number 63 / 635,177, filed on April 17, 2024, the entire disclosure of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This disclosure is directed to determining a target position for a component for die bonding to a bond location of a substrate.TECHNICAL BACKGROUND AND STATE-OF-THE ART

[0003] Die bonding is a process by which a component, for example, a die or a semiconductor die, is attached to a bond location of a substrate to form a package. In order to ensure proper alignment between the component and the bond location for bonding, metrology systems are often used to determine positions of alignment marks or other structures on the component and on the substrate at the bond location. The determined positions of the alignment marks are then used to calculate correction vectors, which are applied to a nominal target position to determine a corrected target position for bonding.

[0004] As contact pad pitches of components and / or substrates become smaller due to technological advances, the required placement accuracy increases. For example, advanced bonding processes, such as hybrid bonding, may utilize contact pad pitches less than 10 pm. This imposes a placement accuracy requirement of about 100 nm or less at 3 sigma, and, with a target position determination requirement of 1 / 10thof the placement accuracy, the target position should be determined with an accuracy within 10 nm at 3 sigma.

[0005] Conventional metrology systems utilize cameras, for example 2-dimensional image sensors located at image planes of high-resolution optical imaging lenses, to determine positions of alignment marks or other structures. Cameras, however, are often limited in their ability to determine very fine distances. For example, a typical edge detection algorithm may be able to detect a shift 1 / 50 of a pixel. Thus, given a pixel size of 2.5 pm, for example typical for a high-resolution camera system, in an ideal case, at least a 5x magnification would be required to achieve the 10 nm accuracy. In non-ideal cases, much higher magnification may be necessary. Among other issues, increased magnification reduces field-of-view.

[0006] Furthermore, alignment marks are becoming increasingly smaller, for example due to space constraints. In order to resolve smaller alignment marks, cameras need to have increasingly large numerical apertures. For example, an alignment mark with a size of 20 pm x 20 pm may necessitate a numerical aperture of greater than 0.5, or even greater than 0.8. Such numerical apertures often require large and heavy lenses and smaller working distances, which may be impractical for use in a die bonder. This may be especially true for a metrology system that is moveable, for example coupled to the bond head or other movable structure.

[0007] Yet further, camera-based metrology systems often suffer from contrast issues due to reflectivities of background materials in the proximity of or within alignment marks. For example, the reflectivity of bare silicon is already > 30%, and it may be much higher due to thin film interference. Accordingly, camera-based metrology systems are becoming increasingly unable, or impractical, to resolve positions of components and / or bond locations for advanced die bonding applications.SUMMARY OF THE INVENTION

[0008] A method of determining a corrected target position for a component at a bond location of a substrate is described herein. The method includes establishing a spatial relationship between the component and an up-looking metrology system such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system. The method also includes determining a position of the component alignment mark relative to the up-looking metrology system. The method further includes determining, based on the position of the component alignment mark, a component correction vector. The method also includes establishing a spatial relationship between the substrate and a down-looking interferometer such that a substrate alignment mark of the substrate proximate the bond location is within a sensitivity range of the down-looking interferometer. The method further includes determining a phase of at least one diffracted beam from an illumination of the substrate alignment mark using the down-looking interferometer. The method also includes determining,based on the phase of the diffracted beam from the substrate alignment mark, a position of the substrate alignment mark relative to the down-looking interferometer. The method further includes determining, based on the position of the substrate alignment mark, a substrate correction vector. The method also includes determining the corrected target position based on the component correction vector and based on the substrate correction vector.

[0009] A die bonder configured to perform the method discussed above is also described herein. The die bonder includes a component supply system configured to supply the component, a substrate supply system configured to supply the substrate, a drive system configured to enable the spatial relationships, the down-looking interferometer, and the up-looking metrology system. The die bonder may include one or more processing units configured to perform the method discussed above.

[0010] A method of determining a component correction vector for a component within a die bonder is also described herein. The method includes releasably attaching the component to a bond head of the die bonder. The method also includes positioning the bond head such that a component alignment mark of the component is within a sensitivity range of an up -looking interferometer of the die bonder. The method further includes determining a phase of at least one diffracted beam from an illumination of the component alignment mark using the up-looking interferometer. The method also includes determining, based on the phase of the diffracted beam from the component alignment mark, a position of the component alignment mark relative to the up-looking interferometer. The method further includes determining a component correction vector for the component based on the position of the component alignment mark.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. 1 illustrates a coarse move to create a spatial relationship between an up-looking metrology system and a component alignment mark on a component.

[0012] FIG. 2 illustrates example structures on the component that may be usable for the coarse move and / or for interferometry.

[0013] FIG. 3 illustrates determining a component correction vector using the up-looking metrology system.

[0014] FIG. 4 illustrates a coarse move to create a spatial relationship between a down-looking interferometer and a substrate alignment mark at a bond location on a substrate.

[0015] FIG. 5 illustrates determining a substrate correction vector using the down-looking interferometer.

[0016] FIG. 6 illustrates calibration between the up-looking metrology system and the downlooking interferometer.

[0017] FIGS. 7A and 7B illustrate an example method of target position determination for a component at a bond location of a substrate using interferometry.

[0018] FIG. 8A illustrates a side view of interferometric principals usable for target position determination for a component at a bond location of a substrate using interferometry.

[0019] FIG. 8B illustrates a plan view of an illumination spot of an interferometer in the middle of an alignment mark.

[0020] FIG. 8C illustrates a plan view of an illumination spot of an interferometer offset from the middle of the alignment mark of FIG. 9B.

[0021] FIG. 9 illustrates an example configuration of the down-looking interferometer.

[0022] FIG. 10 illustrates an example configuration of the down-looking interferometer.

[0023] FIG. 11 A illustrates an example configuration of the down-looking interferometer that includes a camera.

[0024] FIG. 11B illustrates another example configuration of the down-looking interferometer that includes a camera.

[0025] FIG. 12A illustrates an example configuration of the down-looking interferometer and the up-looking metrology system that may be used for calibration between the down-looking interferometer and the up-looking metrology system when the up-looking metrology system is an up-looking camera.

[0026] FIG. 12B illustrates an example of a calibration mark that may be used within the example configuration of FIG. 12A.

[0027] FIG. 12C illustrates an example configuration of the down-looking interferometer and the up-looking metrology system that may be used for calibration between the down-looking interferometer and the up-looking metrology system when the up-looking metrology system is an up-looking interferometer.

[0028] FIG. 13 illustrates an example configuration of the down-looking interferometer that utilizes a symmetric layout.

[0029] FIG. 14A illustrates an example configuration of the down-looking interferometer that utilizes a Littrow geometry.

[0030] FIG. 14B illustrates another example configuration of the down-looking interferometer that utilizes a Littrow geometry.

[0031] FIG. 15A illustrates an example configuration of the down-looking interferometer that utilizes multiple beams.

[0032] FIG. 15B illustrates another example configuration of the down-looking interferometer that utilizes multiple beams.

[0033] FIG. 16 illustrates an example configuration of the down-looking interferometer configured for use in determining the z-error of FIG. 6.

[0034] FIG. 17 illustrates a die bonder configured for target position determination for a component at a bond location of a substrate using interferometry.DETAILED DESCRIPTION OF THE INVENTION

[0035] As contact pad pitches of components and / or substrates used for die bonding get smaller due to technological advances and packaging requirements, so too does the required placement accuracy of components. For example, some modern processes necessitate a placement accuracy within 100 nm at 3 sigma and a target position determination requirement of 10 nm at 3 sigma. In order to achieve such accuracy, conventional camera-based metrology systems may require, even in an ideal case, at least a 5x magnification. In non-ideal cases, much higher magnification may be necessary. Among other issues, increased magnification reduces field-of-view of such systems. Furthermore, camera-based metrology systems may require a high numerical aperture, for example a numerical aperture > 0.3, to resolve the size of modern alignment marks, for example alignment marks sized 20 pm x 20 pm or smaller. Such numerical apertures often require large and heavy lenses and smaller working distances, which may be impractical for use in a die bonder. Accordingly, camera-based metrology systems are becoming increasingly unable, or impractical, to resolve positions of components and / or bond locations in advanced die bonding applications.

[0036] Methods, apparatuses, and systems for target position determination for a component at a bond location of a substrate using interferometry are described herein. In a die bonder, an alignment mark that is on a component or on a substrate is placed within a sensitivity range of an interferometer. A phase of at least one diffracted beam from an illumination of the alignment mark is determined using the interferometer and used to determine a position of the alignment mark relative to the interferometer. Based on the position of the alignment mark relative to the interferometer, a correction vector is determined and applied to a nominal target position for the component to determine a corrected target position for the component. The nominal target position may represent an expected target position and may be determined based on positional information, such as geometry data (e.g. of parts of the die bonder 106, the component 100, and / or the substrate 104), controller data, and / or calibration data. The corrected target position is then used to bond the component to the substrate.

[0037] By using the interferometer, the alignment mark can be made very small. Furthermore, the interferometer enables a determination of a very accurate correction vector. Accordingly, very accurate placement of components relative to bond locations may be realized using little surface area for alignment marks. In so doing, the package may be made smaller, more robustly, to have more space for other components / functions, for less cost, and / or with less production time.

[0038] FIGS. 1-6 illustrate example steps, for example processes, stages, phases, etc., of target position determination for a component 100 at a bond location 102 of a substrate 104 using interferometry. The steps correspond to an environment of a die bonder 106 (e.g., an interior of the die bonder 106). The steps may be split, rearranged, and / or combined without departing from the scope of this disclosure. Furthermore, any of the steps or portions of the steps may be performed in conjunction with and / or by an associated system (e.g., a remote computing device). For example, positions or other variables may be calculated by a remote computing device.

[0039] The die bonder 106 includes a substrate holder (not shown) that is typically stationary, a bond head 108 that is movable, for example coupled to a drive system, a down-looking metrology system, hereinafter referred to as a down-looking interferometer 110, that is movable, for example coupled with the bond head or with a separate drive system, and an up-looking metrology system 112 that is typically stationary. The down-looking interferometer 110 isconfigured to determine a location of the bond location 102 of the substrate 104 held by the substrate holder, and the up-looking metrology system 112 is configured to determine a location of the component 100 that is releasably attached to the bond head 108.

[0040] At least one of the down-looking metrology system or the up-looking metrology system includes an interferometer. In cases where only one of the metrology systems includes an interferometer, the other may constitute a camera-based metrology system. For example, the up- looking metrology system 112 may include an interferometer and the down-looking metrology system may not. If both of the metrology system include interferometers, configurations of the interferometers may be similar or different.

[0041] FIG. 1 illustrates a coarse move to create a spatial relationship between the up-looking metrology system 112 and a component alignment mark 114 on the component 100. In FIG. 1 the component 100 is releasably attached to the bond head 108. Accordingly, one or more steps may occur prior to FIG. 1. For example, the bond head 108 may move to a component supply system (not shown) and a single or double flip of the component 100 may occur prior to the component 100 being releasably attached to the bond head 108.

[0042] To establish the spatial relationship between the component alignment mark 114 and the up-looking metrology system, a relative movement between the component alignment mark 114 and the up-looking metrology system 112, such as a move of the bond head 108, may occur to place the component alignment mark 114 within an up-looking sensing space 113 of the up- looking metrology system 112. The up-looking sensing space 113 defines the volumetric region where light from the component 100 can be collected by the up-looking metrology 112. In some implementations, the up-looking metrology system 112 or other structures may move to create the spatial relationship.

[0043] If the up-looking metrology system 112 is a camera-based metrology system, then the up- looking sensing space 113 may be a field-of-view accounting for the object-side numerical aperture of the camera-based metrology system. If the up-looking metrology system 112 includes an interferometer, then the sensitivity range of the interferometer may be the area of the up-looking sensing space 113 where an alignment mark can be illuminated by an illumination spot 902 of a corresponding interferometer. For example, the up-looking sensing space 113 is the envelope of the incident and diffracted beam bundle of the interferometer 112.

[0044] A sensitivity range, as used herein, refers to a spatial relationship established with sufficient accuracy to where an alignment mark can be illuminated by an illumination spot of a corresponding interferometer. Although the sensitivity range is illustrated as a cone with a point, it should be understood that the sensitivity range corresponds to a small area. If the metrology system is a camera-based system, then the sensitivity range generally refers to a field-of-view at a focal point of the camera-based system.

[0045] If the up-looking metrology system 112 includes an interferometer, the component alignment mark 114 and surrounding materials can be configured to facilitate modulation in phase, amplitude, or a combination of both. The component alignment mark 114 may be separate from contact pads 116 of the component 100, or the contact pads 116 may form the component alignment mark 114, for example act as a grating. The contact pads 116 may be made of copper, aluminum, or other metallic pads with a dielectric like SiCh, SiCN or Si3N4 between the contact pads 116.

[0046] The die bonder 106 may know a general location of the component alignment mark 114 and, thus, not require any additional information to create the spatial relationship between the up- looking metrology system 112 and the component alignment mark 114. For example, the drive system may have one or more encoders to provide a coarse estimate of the location of the bond head 108 and / or the up-looking metrology system 112, for example if it is movable.

[0047] Alternatively or additionally, the die bonder 106 may locate the component alignment mark 114. For example, if the up-looking metrology system 112 includes an interferometer, in the coarse move, structures typically found on the component surface (e.g., contact pads 116 discussed in regard to FIG. 2) may be detected via a camera (e.g., up-looking camera) to locate the component alignment mark 114 and to position the interferometer, for example by moving the bond head 108). Furthermore, the structures used for the coarse move may be a portion of, be, and / or include the component alignment mark 114.

[0048] FIG. 2 illustrates example structures on the component that may be usable for the coarse move discussed in regard to FIG. 1 and / or as the component alignment mark 114. Various structures may be usable as alignment markers. For example, the component 100 may have a die edge 200, a seal ring 202, and contact pads 116. The seal ring 202 or the die edge 200 may be detectable by a camera within the up-looking metrology system. Alternatively or additionally, acontrast due to reflectivity differences between the contact pads 116 and a surrounding dielectric may be detectable by the camera. By determining locations of any of the structures, the die bonder 106 can create the spatial relationship between the up-looking metrology system 112 and the component alignment mark 114 with sufficient measurement accuracy such that the component alignment mark 114 is within the up-looking sensitivity range 113.

[0049] It should be noted that the coarse move may not be necessary if the move of the bond head 108 is accurate to be within the field-of-view or sensitivity range of the up-looking metrology system 112. In such cases, the process may start with that of FIG. 3.

[0050] FIG. 3 illustrates determining a component correction vector using the up-looking metrology system 112. The component correction vector corresponds to an offset between the up-looking metrology system 112 and the component alignment mark 114. In other words, the component correction vector represents a shift or offset from a nominal or expected location of the component 100 to an actual location of the component 100.

[0051] A small local move may be necessary during this step to determine the component correction vector. If the up-looking metrology system 112 is a camera-based metrology system, a snapshot of the component alignment mark 114 may be usable to determine the component correction vector for the component 100. If the up-looking metrology system 112 includes an interferometer, then the principals discussed below regarding interferometry may be usable to determine the component correction vector.

[0052] In general, the principals discussed below regarding interferometry are described in relation to a measurement along a single direction (x). To obtain two dimensions of the component correction vector, the component alignment mark 114 may be a two-dimensional (2D) periodic (e.g., a 2D array of pads in x and y, a 2D grating, or a 2D alignment mark). Because the light discussed below diffracts in the orthogonal direction (y) when it impinges on a 2D alignment mark, other sensors may be used to detect a phase shift, and thus, offset, in the other direction (y). Alternatively or additionally, separate interferometers and / or separate ID alignment marks may be used for measurements along respective axes.

[0053] In some implementations where the up-looking metrology system 112 includes an interferometer, the die bonder 106 (or associated system) may be able to determine the component correction vector on approach to the target of the coarse move (e.g., on approach towhere an illumination spot 902 of the interferometer is within the component alignment mark 114 and / or without stopping prior to using / gathering data from the interferometer). In other words, the steps of FIGS. 1-3 may be replaced by a single move of the bond head 108.

[0054] In some implementations, the above steps may be repeated for another component alignment mark (not shown) on the component 100. Another correction vector may be determined for the component 100 based on the other component alignment mark, which can be combined with the component correction vector to determine a final component correction vector and / or a rotation for the component.

[0055] FIG. 4 illustrates a coarse move to create a spatial relationship between the down-looking interferometer 110 and a substrate alignment mark 500 on the substrate 104. The substrate alignment mark 500 may correspond to the bond location 102. To create the spatial relationship, the bond head 108 may be moved such that the substrate alignment mark 500 is within a downlooking sensitivity range 111 of the down-looking interferometer 110. If there is another or additional drive system corresponding to the down-looking interferometer 110, then the other drive system may be involved in the move.

[0056] The die bonder 106 may know a general location of the substrate alignment mark 500 and, thus, not require any additional information to create the spatial relationship between the down-looking interferometer 110 and the substrate alignment mark 500. For example, the drive system may have one or more encoders to provide a coarse estimate of the location of the bond head 108 and / or the down-looking interferometer 110.

[0057] Alternatively or additionally, the die bonder 106 may locate the substrate alignment mark 500. For example, in the coarse move, structures typically found on the substrate 104 may be used by a camera (e.g., not shown) to locate the substrate alignment mark 500 and to position an illumination spot 902 of the down-looking interferometer 110 (e.g., by moving the bond head 108). For example, the camera may be fixed to, or be a part of, the down-looking interferometer 110.

[0058] Similar structures to those shown in FIG. 2 may also exist on the substrate 104 (e.g., proximate the bond location 102). Accordingly, such structures may be usable for the coarse move of FIG. 4. The structures may include a bond location edge, a seal ring, and / or contact pads. Alternatively or additionally, other major structures in the dicing lanes of the substrate 104may be detectable by the camera . Alternatively or additionally, a contrast due to reflectivity differences between the contact pads and a surrounding dielectric may be detectable by the camera. By determining locations of any of the structures, the die bonder 106 can place the substrate alignment mark 500 with sufficient accuracy to position an illumination spot 902 of the down-looking interferometer 110 within the substrate alignment mark 500. As discussed above, the structures may also be the substrate alignment mark 500. For example, pads of the bond location 102 may form or otherwise make up the substrate alignment mark 500.

[0059] Similar to the mark(s) of the component 100, the coarse move may not be necessary if the move of the bond head 108 is accurate to be within the sensitivity range of the down-looking interferometer 110. In such cases, the process may skip to that of FIG. 5.

[0060] FIG. 5 illustrates determining a substrate correction vector using the down-looking interferometer 110. The substrate correction vector represents a shift or offset from a nominal location of the bond location 102 to an actual location of the bond location 102. A small local move may be necessary during this step to determine the substrate correction vector. The downlooking interferometer 110 may be usable, based on the principals discussed below, to determine the substrate correction vector for the bond location 102.

[0061] In general, the principals discussed below are described in relation to a measurement along a single direction (x). To obtain two dimensions of the substrate correction vector, the substrate alignment mark 500 may be two-dimensional (2D) periodic (e.g., a 2D array of pads in x and y, a 2D grating, or a 2D alignment mark). Because the light discussed below diffracts in the orthogonal direction (y), other interferometers may be used to detect a phase shift, and thus, offset, in the other direction (y). Alternatively or additionally, a 2D interferometer may be used to simultaneously detect phase shifts in both dimensions to obtain the substrate correction vector.

[0062] In some implementations, the die bonder 106 (or associated system) may be configured to determine the substrate correction vector during the coarse move, for example on approach to where the illumination spot 902 of the down-looking interferometer 110 is within the substrate alignment mark 500. In other words, the steps of FIGS. 4 and 5 may be replaced by a single move of the bond head 108.

[0063] In some implementations, the above steps may be repeated for another substrate alignment mark (not shown) corresponding to the bond location 102. Another substratecorrection vector may be determined for the bond location, which can be combined with the substrate correction vector to determine a final substrate correction vector and a rotation for the bond location 102.

[0064] It should be noted that the substrate correction vector and / or the substrate rotation may be determined prior to determining the component correction vector and / or component rotation. As the two vectors / rotations are combined to determine a final target position for the component 100, the order of determination is not consequential.

[0065] FIG. 6 illustrates a calibration between the down-looking interferometer 110 and the up- looking metrology system 112. The calibration produces a coordinate mapping between the down-looking interferometer 110 and the up-looking metrology system 112. The calibration may be performed with or without the component 100 being releasably attached to the bond head 108. The calibration may be performed any time (e.g., at die bonder setup, before, during, or after a bonding) and at any frequency (e.g., once, during every bond cycle, every x-number of bond cycles, once in a specific time period, etc.). The calibration enables an adjustment of and / or calibration between the down-looking interferometer 110 and the up-looking metrology system 112. Repeating the calibration may compensate for possible changes in the downlooking interferometer 110 and / or the up-looking metrology system 112 and / or to update the coordinate mapping. Details of the calibration are discussed below in regard to FIGS. 12A-C.

[0066] The component correction vector and rotation (if it exists) for the component 100, the substrate correction vector and rotation (if it exists) for the bond location 102, and the mapping are combined to determine a final correction vector and rotation for the component 100. The final correction vector and rotation are applied to a nominal target position for the component 100 to determine a corrected target position for the component 100 for bonding to the bond location 102.

[0067] FIG. 7 illustrates a method 800 of target position determination for a component at a bond location of a substrate using interferometry. The method 800 may be performed by a die bonder, an associated system, or some combination thereof. Steps of the method 800 may be rearranged, split, or combined without departing from the scope of this disclosure.

[0068] At S802, a coordinate system mapping is determined between an up-looking metrology system and a down-looking interferometer of a die bonder. For example, the coordinate mapping discussed in regard to FIG. 6 may be determined. As discussed above, the coordinate systemmapping (e.g., calibration), may occur during die bonder setup and, optionally, any number of times after that. The coordinate system mapping may include the down-looking interferometer moving over the up-looking metrology system, such that their respective axes are aligned, and various other steps to determine the mapping between the coordinate systems of the down-looking interferometer and the up-looking metrology system.

[0069] S804-S826 correspond to a bonding sequence of a component to a bond location of a substrate. Within that, S806-S824 correspond to determining a corrected target position for the component at the bond location.

[0070] At S804, the component is releasably attached to a bond head, and a substrate is disposed within the die bonder. For example, the component may be picked up from a component supply system (e.g., via a single or double flip). The substrate may be held by a substrate supply system.

[0071] At S806, the bond head is moved such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system. For example, the bond head may move via a single move or via a coarse and fine move (as discussed above).

[0072] At S808, an image or phase information about the component alignment mark is captured by the up-looking metrology system. For example, if the up-looking metrology system is a camera-based metrology system, then an image of the component alignment mark may be captured. If the up-looking metrology system includes an up-looking interferometer, then the component alignment mark may be illuminated by the up-looking interferometer such that phase information can be captured.

[0073] At S810, a component correction vector is determined based on the captured image or phase information. The component correction vector may be a vector with two orthogonal components (e.g., x and y). For example, if the up-looking metrology system is a camera-based metrology system, then the image may be usable to determine the component correction vector based on pixel shift or other techniques. If the up-looking metrology system includes an up- looking interferometer, then the phase information for respective diffracted beams in two orthogonal axes may be usable to determine the component correction vector.

[0074] Optionally, at S812, the bond head may be moved such that another component alignment mark of the component is within the field-of-view or sensitivity range of the up-looking metrology system. Another image or other phase information may be captured by the up-looking metrologysystem for the other component alignment mark. Another component correction vector may then be determined based on the other captured image or other phase information. The other component correction vector may then be combined with the component correction vector to determine a final component correction vector and rotation for the component.

[0075] At S814, the bond head is moved such that a substrate alignment mark corresponding to the bond location of the substrate is within a sensitivity range of the down-looking interferometer. For example, the bond head may move via a single move or via a coarse and fine move (as discussed above).

[0076] At S816, phase information from an illumination of the substrate alignment mark is captured by the down-looking interferometer.

[0077] At S818, a substrate correction vector is determined based on the phase information. The substrate correction vector may be a vector with two orthogonal components (e.g., x and y). For example, the phase information for respective diffracted beams in two orthogonal axes may be usable to determine the substrate correction vector.

[0078] Optionally, at S820, the bond head may be moved such that another substrate alignment mark corresponding to the bond location is within the sensitivity range of the down-looking interferometer. Other phase information may be captured by the down-looking interferometer for the other substrate alignment mark. Another substrate correction vector may then be determined based on the other phase information. The other substrate correction vector may then be combined with the substrate correction vector to determine a final substrate correction vector and rotation for the bond location.

[0079] At S822, the component correction vector is mapped to the substrate correction vector. If the component correction vector and the substrate correction vector are final or combined correction vectors. Then the final correction vectors may be mapped with the corresponding rotations. The output of S822 is a target correction vector and, optionally, a target rotation for the component.

[0080] At S824, the target correction and target rotation (if it exists) is applied to a nominal target position corresponding to the bond location to produce a corrected target position.

[0081] At S826, the bond head is moved to the corrected target position, and the component is bonded to the bond location.

[0082] FIGS. 8A-8C illustrate principals of interferometry using the substrate alignment mark 500 with a periodic arrangement of alignment mark features 901. FIG. 8 A illustrates a side view of the substrate alignment mark 500 and illumination by the down-looking interferometer 110. FIG. 8B illustrates a plan view of an illumination spot 902 of the down-looking interferometer 110 centered on the substrate alignment mark 500 in a sensing direction. FIG. 8C illustrates a plan view of the illumination spot 902 of the down-looking interferometer 110 offset from the center of the substrate alignment mark 500 in the sensing direction. The principals discussed below may also be applicable to the up-looking interferometer (if implemented).

[0083] The substrate alignment mark 500 includes a series of alignment mark features 901 (e.g., lines) with a feature pitch d, which causes the substrate alignment mark 500 to act as a grating. The alignment mark features 901 may comprise exposed metal (e.g., beneath a surrounding substrate), deposited metal (e.g., above a surrounding substrate) with or without a dielectric between the alignment mark features 901, or metal completely encapsulated within an optically transparent dielectric. The width of the alignment mark features 901 and the feature pitch may vary depending upon implementation, sensing distances, accuracy requirements, size of the substrate alignment mark 500.

[0084] The substrate alignment mark 500 is illuminated with an incident beam 904 that creates the illumination spot 902 (not shown in FIG. 8A). The incident beam 904 (not shown in FIG. 8B and FIG. 8C) may be a laser beam, as laser beams exhibit well-defined propagation according to a paraxial wave equation and can be collimated and focused in a highly controlled manner (e.g., a size of the illumination spot 902 may be minimized). Furthermore, laser beams are coherent (e.g., they have a coherence length of at least 0.1 mm) which allows for interferometric measurements by overlapping the beam with a reference beam.

[0085] The incident beam 904 is reflected by the substrate alignment mark 500 to produce a reflected beam 906 (e.g., O-th order) and is diffracted by the substrate alignment mark 500 to produce a diffracted beam 908 (with one or more orders). The diffracted beam 908 is determined by a grating equation in reflection, where a diffraction angle f>mof the m -th diffraction order relates by:where a is an angle of the incident beam 904 relative to a normal direction of the substrate alignment mark 500 and X is a wavelength of the incident beam 904.

[0086] In the case of visible light (e.g., 400-700 nm) and very small feature pitches (e.g., < 1 pm) the first few diffraction orders (-1, 0, 1) may be diffraction possible according to the sine conditions.

[0087] While intensities of the diffracted beam 908 are defined by exact optical properties of the substrate alignment mark 500, the phase component of the diffracted beam 908 depends on an offset of the substrate alignment mark 500 with respect to the incident beam 904. The phase shift A< > is given by:

[0088] Accordingly, the down-looking interferometer 110 may determine an offset Ax in the substrate alignment mark 500 based on detected phase shifts in the diffracted beam 908. The offset corresponds to one direction component of an associated correction vector (in this case, the x direction). Depending on the wavelength, the feature pitch, and the diffraction, the downlooking interferometer 110 may not be able to detect the offset beyond a certain distance that is in the order of the feature pitch (e.g., because the phase is 27r-periodic). To determine the offset, positioning of the substrate alignment mark 500 relative to the illumination spot 902 may need to be within the feature pitch (e.g., the alignments discussed above).

[0089] FIG. 9 illustrates an example configuration of the down-looking interferometer 110. The example configuration may also be used within the up-looking metrology system 112 (if an interferometer is implemented) and / or in combination with any other example configurations described herein.

[0090] The offset (Ax) in the substrate alignment mark 500 can be measured from measuring the reflected beam 906 (O-th order) and the diffracted beam 908 (-1-th order). The reflected beam 906 is coherently overlay ed with the diffracted beam 908 at a beam splitter 910. The reflected beam 906 may be reflected by a mirror 912 to reach the beam splitter 910. As shown in FIG. 9 and other figures below, an optical component with a single input and a single output may be a mirror (e.g., the mirror 912), and an optical component with multiple inputs and / or multiple outputs (unless otherwise stated) may be a beam splitter (e.g., the beam splitter 910).

[0091] Photodetectors 1000 are configured to measure intensities IABy taking the difference of the intensities and normalizing to the sum of the intensities (e.g., a visibility or contrast between the beams), an offset signal that is highly sensitive to the phase difference and independent of amplitude fluctuations can be derived. For example, the offset may be given according to:

[0092] The photodetectors 1000 (in this configuration or in any configuration discussed above or below) may be photodiodes. The photodiodes may operate in various regimes, be unbiased, be biased, be of an amplified type, be of an avalanche type, be solid-state, and / or be photomultiplier tubes. Furthermore, the photodetectors 1000 may be position-sensing detectors (PSD), such as quadrant photodiodes or photodiode arrays. PSDs operate with high bandwidth like single-point detectors, but they give feedback about the beam position or overlapping beam angle via their differential output. Doing so may help with alignment of the down-looking interferometer 110 and the up-looking metrology system 112, if it includes an interferometer, and calibration therebetween, as discussed below.

[0093] FIG. 10 illustrates an example configuration of lenses that may be used within the downlooking interferometer 110. The example configuration may also be used within the up-looking metrology system 112, if it includes an interferometer.

[0094] One challenge in projecting the incident beam 904 onto a small target is controlling beam divergence. For example, to hit a 20 pm x 20 pm alignment mark, the beam waist w0according to paraxial beam optics should be less than or equal to 10 pm. Accordingly, the beam divergence for visible light is then:

[0095] A 1° divergence correlates to a beam size of less than 2 mm at a distance of 100 mm. It should be noted that a l°divergence is much smaller than a light collection angle (e.g., numerical aperture) of a camera-based metrology system that is able to resolve sub-micron structures. For example, the light collection angle may be greater than 30° for numerical apertures greater than0.3. Accordingly, implementation of an interferometer (or multiple interferometers) allows for much larger working distances compared to a traditional camera-based metrology system.

[0096] In the example configuration, a light source 1100 produces illumination. The light source 1100 may be a laser, light-emitting diode (LED), super luminescent LED (SLED), or other light source and may produce light in the visible spectrum or outside of the visible spectrum (e.g., ultraviolet).

[0097] The light from the light source 1100 may be conditioned by a collimator lens 1102 that is matched to the light source 1100 to collimate the beam at a beam radius. The collimated beam then progresses through a focusing lens 1104 to focus the beam onto the substrate alignment mark 500 with a long working distance (e.g., up to 100 mm or more). A reflection lens 1106 collects the reflected beam 906, and a diffraction lens 1108 set at the diffraction angle f>mcollects the diffracted beam 908 (m-th order).

[0098] In some implementations, the intrinsic light source mode will not be matched to the beam relay optics for optimal focusing. Therefore, additional optical elements may be implemented to condition the beam. For example, a beneficial mode is the ground mode of a gaussian beam (e.g., TEM00). For a bare laser diode, whose source region is often a high-aspect ratio semiconductor layer, an astigmatic telescope may be used to circularize the beam. Furthermore, the light source 1100 may be coupled by a single mode fiber, preferably a polarizationmaintaining fiber. Additionally, a spatial mode filter, such as a single mode fiber or a pinhole, may be used. Also, to increase sensitivity of the phase measurement in the presence of noise, the beam may be modulated with the help of an electro-optic or acousto-optic modulator to facilitate detection with the help of a lock-in amplifier.

[0099] FIGS. 11 A and 1 IB illustrate an example configuration of the down-looking interferometer that includes a camera 1200. FIG. 11 A illustrates using diffractive sensing to detect the diffracted beam, and FIG. 1 IB uses the camera 1200 to sense the diffracted beam. In some implementations, both sensing methods may be used (e.g., redundancy, extra precision) and / or with other configurations described herein. Furthermore, the example configuration may be used within the up-looking metrology system (if it includes an interferometer).

[0100] As shown in FIG. 11 A, the camera 1200 may be used to augment operation of an interferometer configured similarly to that of FIG. 9. For example, the camera 1200 may aidalignment and calibration by detecting large structures (e.g., as discussed below in regard to FIGS. 12A-12C) and may serve as an inspection tool.

[0101] Furthermore, the camera 1200 may be used for detection of the diffracted beam 908. For example, instead of the incident beam 904 being focused (e.g., as in FIG. 11 A), illuminating a larger area (e.g., as in FIG. 1 IB) coherently creates the diffracted beam 908 that may be overlay ed with the reflected beam 906 within the camera 1200 to record an interferogram. If the beams are parallel, an on-axis holographic image may be generated. The phase can then be reconstructed by phase-retrieval methods such as the Gerchberg-Saxton algorithm.

[0102] If the beams are not parallel, an off-axis holographic image can be generated, creating a shift in the Fourier domain. By doing so, the reconstruction may be simpler by using Fourier transforming, filtering in the Fourier domain, and taking the inverse Fourier transform.

[0103] FIG. 12A illustrates an example configuration for calibration between the up- looking metrology system 112 and the down-looking interferometer 110 (e.g., related to FIG. 6 and S802) when the up-looking metrology system 112 is a camera-based metrology system. For this configuration, a calibration plate 1300 may be placed between the up-looking metrology system 112 and the down-looking interferometer 110. For example, the up-looking metrology system 112 and the calibration plate 1300 may be used to detect the illumination spot 902 of the down-looking interferometer 110 relative to a calibration alignment mark 1302 on the calibration plate 1300. The interferometer position and, if necessary, the beam path within the down-looking interferometer 110, may be adjusted to place the illumination spot 902 at a center of the calibration alignment mark 1302, which corresponds to a zero-offset. To obtain 2D calibration, the calibration alignment mark 1302 may be a 2D array of alignment mark features 901.

[0104] FIG. 12B illustrates an example of the calibration alignment mark 1302 that may be used on the calibration plate 1300 in the example configuration of FIG. 12A. The calibration alignment mark 1302 may include a grating portion 1304 detectable by the down-looking interferometer and a plurality of fiducials 1306 (e.g., circular or other shaped features) equally arranged around the grating portion 1304 detectable by the up-looking metrology system 112. By determining a difference between an offset determined by the down-looking interferometer110 and an offset determined by the up-looking metrology system 112, the coordinate mapping between the two systems can be determined.

[0105] FIG. 12C illustrates an example configuration for calibration between the up- looking metrology system 112 and the down-looking interferometer 110 when the up-looking metrology system 112 includes an interferometer. In this configuration, the photodetectors 1000 in both interferometers may be PSDs to enable alignment / calibration of two opposite facing interferometers. To do so, beams from the up-looking metrology system 112 and the downlooking interferometer 110 may be coupled such that the PSDs give a highly sensitive alignment signal. It should be noted that use of PSDs in the two interferometers may allow for calibration without the calibration plate 1300.

[0106] Alternatively or additionally, PSDs may be used to monitor the beam position before, during, and / or after the interferometric measurement is conducted. This gives additional information on the relative orientation of the substrate 104 and / or component 100 relative to a principal alignment of the interferometer. In addition to 2D sensing (e.g., a correction vector), the z position can be measured with an “autofocus” interferometer (3 degrees-of-freedom), and the rotations may provide for determining up to 6 degrees-of-freedom relative to the target.

[0107] Alternatively or additionally, in this configuration, the calibration plate 1300 may be used. For example, a camera within each of the metrology systems / interferometers (e.g., similar to that of FIGS. 11 A and 1 IB) may be used to determine an initial offset based on the fiducials 1306. The interferometers may then be used for calibration using the grating portion 1304.

[0108] Regardless of configuration, the interferometer(s) may also be initially aligned. Initial alignment corresponds to the beam path(s) being routed along nominally designed paths by properly adjusting optical elements of the interferometer(s). For example, mirrors (not shown) may be adjusted in two angles (tip and tilt) to steer the angle of the beam(s). Combining the adjustment of multiple optical elements gives enough degrees of freedom to precisely control the beam path(s). The optical elements may be adjusted automatically using actuators or using set screws. The camera(s) (if implemented) may detect the location of an illumination spot 902 to center the beam, or the deviation may be calculated by combining the geometrical layout with a beam offset signal from the PSDs (if implemented).

[0109] Further, the contrast of the interferometer(s) (e.g., signal-to-noise ratio), which is related to the beam overlap, can be determined in this manner. This may require further adjustment of the beam path to optimize the contrast. One way of measuring the contrast is to change the relative offset between the alignment mark, maybe across several periods, to determine a sinewave signal. The contrast can then be calculated from the maximum and minimum signal observed.

[0110] FIG. 13 illustrates an example configuration of the down-looking interferometer 110 that utilizes a symmetric layout. The example configuration may be used within the up- looking metrology system 112 if it includes an interferometer and may be combined with any other example configurations discussed above or below.

[0111] The example configuration allows for measurement of the -1 and +1 orders of the diffracted beam 908 and the reflected beam 906 (O-th order) simultaneously. By doing so, two phase signals (e.g., at A< >AXand the doubled phase 2 AAx) may be generated. This gives two correlated signals to improve sensitivity. Up to 8 different combinations of phase measurements may be used for further increased sensitivity and robustness.

[0112] FIG. 14A illustrates an example configuration of the down-looking interferometer that utilizes Littrow geometry. The example configuration may be used within the up-looking metrology system (if it includes an interferometer) and may be combined with any other example configurations discussed above or below.

[0113] The Littrow geometry corresponds to where the -1 order of the diffracted beam 908 is reflected back into the incident beam 904. The Littrow condition is given by the grating equation under the condition that incident angle is the same as the diffracted beam angle0 — arcsin— (5)

[0114] FIG. 14B illustrates another example configuration of the down-looking interferometer that utilizes Littrow geometry. The example configuration may be used within the up-looking metrology system (if it includes an interferometer) and may be combined with any other example configurations discussed above or below.

[0115] The configuration of FIG. 14B is similar to the configuration of FIG. 14A, except that an extra reflection in one of the beams creates a signal that is 180° out of phase. Beam 1500corresponds to an overlay of the Littrow-reflected order -1 and O-th order reflection from the other side.

[0116] FIG. 15A illustrates an example configuration of the down-looking interferometer 110 that utilizes multiple beams. The example configuration may be used within the up-looking metrology system (if it includes an interferometer) and may be combined with any other example configurations discussed above or below.

[0117] In the example configuration, a diffractive optical element (DOE) 1600 (e.g., grating) is used as a splitter using a Littrow configuration (similar to that of FIG. 14A or 14B). The incident beam 904 is diffracted by the DOE 1600 into three DOE diffracted incident beams 1602a-c. DOE diffracted incident beam 1602a corresponds to the 0-order or pass through diffraction (e.g., similar to the incident beam 904). DOE diffracted incident beams 1602b and 1602c may correspond to the 1 and -1 order diffractions of the incident beam 904, respectively, or visa- versa. The DOE diffracted incident beams 1602 impinge on the substrate alignment mark 500, which may be extended or encompass more of the contact pads in this configuration, and are diffracted or reflected, depending upon incident angle. For example, the DOE diffracted incident beam 1602a may be reflected back towards the DOE 1600 as a substrate alignment mark reflected beam 1604. The diffracted incident beam 1602b may be diffracted by the substrate alignment mark 500 to produce a substrate alignment mark diffracted beam 1606. The substrate alignment mark reflected beam 1604 and the substrate alignment mark diffracted beam 1606 then pass through the DOE 1600 and are diffracted. The substrate alignment mark reflected beam 1604 gets diffracted to produce a DOE back diffracted beam 1607a, and the substrate alignment mark diffracted beam 1606 gets diffracted to produce a DOE back diffracted beam 1607b. The DOE back diffracted beams 1607 are then received by a photodetector 1000. For simplicity, only two back-diffracted beams are shown.

[0118] FIG. 15B illustrates another example configuration of the down-looking interferometer 110 that utilizes multiple beams. The example configuration may be used within the up-looking metrology system 112 if it includes an interferometer and may be combined with any other example configurations discussed above or below.

[0119] FIG. 15B is similar to FIG. 15 A except that the DOE is replaced with a polarization beam splitter 1608 like a Wollaston prism. The polarization beam splitter 1608 generates a smallangle between s & p-polarized beams generated by the incident beam 904 going through a polarization controller 1610. The dashed beams are p-polarized beams 1612, and the solid beams are s-polarized beams 1614.

[0120] Using half-wave plates (not shown), the beams can be made to interfere similar to other examples described herein. A small angle between the beams may be compatible with smaller alignment marks (e.g., the substrate alignment mark 500). Furthermore, the configuration of FIG. 15B may allow for longer working distances than that of FIG. 15 A.

[0121] FIG. 16 illustrates an example configuration of the down-looking interferometer 110 that utilizes interference between the incident beam 904 and the reflected beam 906. The example configuration may be used within the up-looking metrology system (if it includes an interferometer) and may be combined with any other example configurations discussed above or below.

[0122] In general, any configuration of the down-looking interferometer 110 may be susceptible to drift (e.g., thermal drift). To address thermal drift, portions of the down-looking interferometer 110, especially a mounting plate or connection to the bond head 108, may be made out of low coefficient-of-thermal expansion (CTE) materials (e.g. invar, dispal, and / or zerodur). Furthermore, the down-looking interferometer 110 may be made as rigid as possible. As another option, the down-looking interferometer 110 may include a housing to protect it from airflow, thereby mitigating temperature change of the down-looking interferometer 110. These mitigations are independent of configuration of the down-looking interferometer 110.

[0123] Another option for mitigating drift is to calculate a z-error. As used herein, the z- error corresponds to a difference between an actual working distance between the down-looking interferometer 110 and the substrate 104 and a nominal distance between the down-looking interferometer 110 and the substrate 104. The z-error may be similar to a defocus error in a camera-based system.

[0124] To determine the z-error, the spatial relationship between the down-looking interferometer 110 and the substrate alignment mark 500 (or the other substrate alignment mark) may be adjusted. For example, a z-distance between the down-looking interferometer 110 and the substrate alignment mark 500 may be changed while the down-looking interferometer 110 is scanning / sampling. Doing so may produce a sinusoidal wave. Fringes of the output, forexample the sinusoidal wave correlate to the z-distance. The z-distance may then be compared to the target distance between the down-looking interferometer 110 and the substrate 104 to generate the z-error. A similar procedure may be used by the up-looking metrology system, if it includes an interferometer, to measure a z-error between the up-looking metrology system 112 and the component 100.

[0125] Returning to the figure, in this example configuration, the down-looking interferometer 110 is stabilized with a second beam. The sensing beam (e.g. the reflected beam 906) is then split off. For example, the reflected beam 906 as sensing beam is not receiving any phase shiftAxdue to an offset from the alignment mark 500, but is following the paths of the diffracted beams 908 closely within the aperture. Therefore, it is sensitive to phase shifts coming from disturbances along the path and the z-position of the alignment mark that also affect the diffracted beams 908. The phase in this beam can be measured by interference with an undisturbed reference beam (e.g. the incident beam 904 split off). In other words, an interference is created between the incident beam and the reflected beam 906 to measure the amount of disturbances and the path length along z

[0126] To stabilize the interferometer, a phase component 1700, such as a phase modulator (e.g., acousto-optic modulator or electro-optic modulator), a piezo-driven mirror, or a controllable delay line, may be used. The phase component 1700 may receive one of the reference beams (e.g., not diffracted), such as the reflected beam 906, and one of the diffracted beams 908. Accordingly, the phase component 1700 may be placed elsewhere within the down-looking interferometer 110 as long as it receives one of the reference beams and one of the diffracted beams 908.

[0127] A feedback controller (not shown) may measure the interference of the incident beam 904 and the reflected beam 906 and adjust the phase with the phase component 1700. In this way, the down-looking interferometer 110 can be zeroed and stabilized over time. For example, tracking the phase allows adjusting for drifts in the setup and changes in the wavelength of the incident beam 904. Furthermore, the example configuration may be useful in determining the z- error.

[0128] The down-looking interferometer 110 may include any number of additional features or components that may be used in a new configuration or in combination with any of the example configurations discussed above.

[0129] For example, additional optical components for polarization control may be included in the beam path of the down-looking interferometer 110. A well-defined polarization state may optimize the design of the down-looking interferometer 110 (e.g., opto-mechanical design) and to improve the signal-to-noise ratio. Such components may include half-wave plates, quarter-wave plates, and / or polarizing beam splitters.

[0130] An example implementation may include colinear routing of two beams of orthogonal polarization that can be separated without affecting each other (multiplexing). Alternatively or additionally, a beam at a polarizing beam splitter may be re-routed via a doublepass configuration of a quarter-wave plate to turn a linearly polarized beam by 90° (e.g. for isolation). Alternatively or additionally, quadrature sampling of a beam interference may be performed using a quarter- wave plate and a polarizing beam splitter in order to get directionality information.

[0131] Any of the features described above in regard to the down-looking interferometer 110 may be used within the up-looking metrology system 112 as long as the up-looking metrology system includes an interferometer. In such cases, the two interferometers (e.g., the down-looking interferometer 110 and the interferometer of the up-looking metrology system 112) need not be alike. For example, because of different requirements, design constraints, and other factors, the down-looking interferometer 110 may have a different configuration than the interferometer of the up-looking metrology system 112.

[0132] FIG. 17 illustrates an example of a system 1800 that may be used for target position determination for a component at a bond location of a substrate using interferometry. The system 1800 includes at least one processing unit 1802, at least one computer-readable storage medium 1804, and a target position determination module 1806. The target position determination module 1806 may be configured to perform the actions discussed above. For example, the target position determination module 1806 may be configured to determine a corrected target location for the component based on interferometry (using information received from one or more of a down-looking interferometer and an up-looking interferometer). The system 1800 (including the processing unit 1802) may be contained within a die bonder performing a bond of the component at the bond location, partially within the die bonder, or communicatively coupled with the die bonder.

[0133] The processing unit 1802 (e.g., one or more of an application processor, central processing unit (CPU), graphics processing unit (GPU), microprocessor, digital-signal processor (DSP), or controller) executes instructions 1808 (e.g., code) stored within the computer-readable storage medium 1804 (e.g., a non-transitory storage devices such as a hard drive, solid-state drive (SSD), flash memory, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM)) to cause the system 1800 to perform the techniques described herein. The instructions 1808 may be part of an operating system and / or one or more applications of the system 1800.

[0134] The instructions 1808 cause the processing unit 1802 to act upon (e.g., create, receive, modify, delete, transmit, or display) data 1810 (e.g., application data, module data, sensor data (e.g., from the down-looking metrology system / down-looking interferometer and / or the up-looking metrology system / up-looking interferometer), or I / O data). Although shown as being within the computer-readable storage medium 1804, portions of the data 1810 may be within a random-access memory (RAM) or a cache of the system 1800 (not shown).Furthermore, the instructions 1808 and / or the data 1810 may be remote to the system 1800.

[0135] The target position determination module 1806 may be comprised by the computer-readable storage medium 1804, be a stand-alone component (e.g., executed in dedicated hardware in communication with the processing unit 1802 and computer-readable storage medium 1804), or some combination thereof. For example, the instructions 1808 may cause the processing unit 1802 to implement the target position determination module 1806 and / or otherwise cause the target position determination module 1806 to perform any number of the actions discussed above.

[0136] The system 1800 may also contain a communication system (not shown) that may be any wired or wireless communication system configured to communicate data over one or more connections or networks. For example, the communication system may be configured to communicate data between the system 1800 and a separate device (e.g., the die bonder if the system 1800 is not implemented within the die bonder).

[0137] Example 1 : A method of attaching a component to a bond location on a substrate, the method comprising: picking the component using a bond head that is coupled to a drivesystem; moving the component, via the drive system, such that an alignment mark of the component is within a field-of-view or sensitivity range of an up-looking metrology system; determining a position of the alignment mark of the component relative to the up -looking metrology system; determining, based on the determined position of the alignment mark of the component relative to the up-looking metrology system, a correction vector for the component; moving a down-looking interferometer such that an alignment mark of the substrate proximate the bond location is within a sensitivity range of the down-looking interferometer; determining a phase of diffracted beams from an illumination of the alignment mark on the substrate using the down-looking interferometer; determining, based on the phase of the diffracted beams from the alignment mark on the substrate, a position of the alignment mark of the substrate relative to the down-looking interferometer; determining, based on the determined position of the alignment mark of the substrate, a correction vector for the substrate; determining a final target position for the component at the bond location based upon the correction vector for the component and the correction vector for the substrate; moving the component, via the drive system, to the final target position; and bonding the component to the substrate.

[0138] Example 2: The method of example 1, wherein: the alignment mark on the substrate has a periodicity; and the moving the down-looking interferometer comprises moving the down-looking interferometer to a positional accuracy within the periodicity of the alignment mark on the substrate.

[0139] Example 3: The method of example 1 or 2, further comprising generating a mapping between the up-looking metrology system and the down-looking interferometer, wherein the determining the final position is based further on the mapping.

[0140] Example 4: The method of example 3, wherein the generating the mapping comprises: moving the down-looking interferometer such that it is aligned with the up-looking metrology system; and moving a calibration plate between the down-looking interferometer and the up-looking metrology system.

[0141] Example 5: The method of example 4, wherein the calibration plate comprises at least one calibration mark that is configured to be viewed by the up-looking metrology system and the down-looking interferometer concurrently.

[0142] Example 6: The method of example 4 or 5, wherein the calibration plate comprises a calibration mark that is less than or equal to 20 micrometers x 20 micrometers.

[0143] Example 7: The method of any preceding example, wherein the up-looking metrology system comprises a camera system.

[0144] Example 8: The method of any preceding example, wherein the up-looking metrology system comprises an up-looking interferometer.

[0145] Example 9: The method of example 8, wherein the method further comprises: determining a phase of diffracted beams from an illumination of the alignment mark on the component using the up-looking interferometer; and determining, based on the phase of the diffracted beams from the alignment mark on the component, a position of the alignment mark of the component relative to the up-looking interferometer.

[0146] Example 10: The method of example 8 or 9, wherein the up-looking interferometer and the down-looking interferometer comprise position-sensing detectors (PSD).

[0147] Example 11 : The method of any preceding example, wherein: the method further comprises: moving the component, via the drive system, such that another alignment mark of the component is within the field-of-view of the up-looking metrology system; determining a position of the other alignment mark of the component relative to the up-looking metrology system; determining, based on the determined position of the alignment mark on the component and the determined position of the other alignment mark of the component, a rotation for the component; moving the down-looking interferometer such that another alignment mark of the substrate proximate the bond location is within the field-of-view of the down-looking interferometer; determining a phase of diffracted beams from an illumination of the other alignment mark on the substrate using the down-looking interferometer; determining, based on the phase of the diffracted beams from the other alignment mark on the substrate, a position of the other alignment mark of the substrate relative to the down-looking interferometer; and determining, based on the determined position of the alignment mark on the substrate and the determined position of the other alignment mark of the substrate, a rotation for the substrate; the correction vector for the component is based further on the determined position of the other alignment mark of the component; the correction vector for the substrate is based further on thedetermined position of the other alignment mark of the substrate; and the determining the final position is based further on the rotation for the component and the rotation for the substrate.

[0148] Example 12: The method of any preceding example, wherein the diffracted beams comprise at least two orders of a negative one, zero, or positive one diffracted beams.

[0149] Example 13: The method of any preceding example, wherein the down-looking interferometer is configured such that a wavelength and incidence angle of an incident beam is matched to a periodicity of the alignment mark effective to diffract a -1 or 1st order according to Littrow's geometry.

[0150] Example 14: The method of any preceding example, wherein the illumination of the alignment mark of the substrate comprises illuminating the alignment mark of the substrate using Gaussian beams with dominant modes TEM00 and a beam parameter M squared that is less than 1.5.

[0151] Example 15: The method of any preceding example, wherein the alignment mark on the substrate is less than or equal to 20 micrometers by 20 micrometers.

[0152] Example 16: The method of any preceding example, wherein a working distance of the down-looking interferometer is at least 10 mm.

[0153] Example 17: The method of any preceding example, wherein the illumination of the alignment mark of the substrate comprises illuminating the alignment mark of the substrate with beams having coherence lengths greater than one tenth of a millimeter.

[0154] Example 18: The method of any preceding example, wherein a feature size of the alignment mark on the substrate is less than 1 micrometer.

[0155] Example 19: The method of example 18, wherein the feature size of the alignment mark on the substrate is a width of a line of the alignment mark on the substrate.

[0156] Example 20: The method of any preceding example, wherein the alignment mark on the substrate comprises a pattern of periodic lines or contact pads which diffract one or more incident beams.

[0157] Example 21 : The method any preceding example, wherein the alignment mark on the substrate is aligned with two linearly independent axes.

[0158] Example 22: A die bonder configured to perform the method of any preceding example.

[0159] Example 23: Computer-readable storage media comprising instructions that cause at least one processor to cause a die bonder to perform the method of any preceding example.

[0160] Example 24: A die bonder comprising: a component supply system; a substrate supply system; a drive system; a bond head coupled to the drive system; a down-looking interferometer coupled to the drive system; and an up-looking metrology system, wherein the die bonder is configured to: pick, using the drive system and the bond head, a component from the component supply system; move, using the drive system, the component such that an alignment mark of the component is within a field-of-view of the up-looking metrology system; determine a position of the alignment mark of the component relative to the up-looking metrology system; determine, based on the determined position of the alignment mark of the component relative to the up-looking metrology system, a correction vector for the component; move, using the drive system, the down-looking interferometer such that an alignment mark of a substrate of the substrate supply system proximate a bond location of the substrate is within a field-of-view of the down-looking interferometer; determine a phase of diffracted beams from an illumination of the alignment mark on the substrate using the down-looking interferometer; determine, based on the phase of the diffracted beams from the alignment mark on the substrate, a position of the alignment mark of the substrate relative to the down-looking interferometer; determine, based on the determined position of the alignment mark of the substrate, a correction vector for the substrate; determine a final target position for the component at the bond location based on the correction vector for the component and the correction vector for the substrate; move, using the drive system, the component to the final target position; and bond, using the bond head, the component onto the substrate.

[0161] Example 25: The die bonder of example 24, wherein the die bonder is further configured to determine the final position for the component based further on an offset between the down-looking interferometer and the bond head.

[0162] Example 26: The die bonder of example 25, wherein the offset is fixed.

[0163] Example 27: The die bonder of example 25, wherein: the die bonder further comprises an interferometer drive system configured to move the down-looking interferometer relative to the bond head; and the offset is based on the movement of the down-looking interferometer relative to the bond head.

[0164] Example 28: The die bonder of any of examples 24-27, further comprising a component transfer system; wherein the die bonder is further configured to pick the component from the component supply system using the component transfer system.

[0165] Example 29: The die bonder of example 28, wherein component transfer system comprises a flip-chip system configured to flip the component.

[0166] Example 30: The die bonder of any of examples 24-29, wherein the die bonder is further configured move the down-looking interferometer to a positional accuracy within a periodicity of the alignment mark on the substrate.

[0167] Example 31 : The die bonder of any of examples 24-30, wherein the die bonder is further configured to: generate a mapping between the up-looking metrology system and the down-looking interferometer; and determine the final position of the component based further on the mapping.

[0168] Example 32: The die bonder of example 31, wherein the die bonder is further configured to generate the mapping by: moving the down-looking interferometer such that it is aligned with the up-looking metrology system; and moving the calibration plate between the down-looking interferometer and the up-looking metrology system.

[0169] Example 33: The die bonder of example 32, wherein the calibration plate comprises at least one calibration mark that is configured to be viewed by the up -looking metrology system and the down-looking interferometer concurrently.

[0170] Example 34: The die bonder of example 32 or 33, wherein the calibration plate comprises a calibration mark that is less than or equal to 20 micrometers x 20 micrometers.

[0171] Example 35: The die bonder of any of examples 24-34, wherein the up-looking metrology system comprises a camera system.

[0172] Example 36: The die bonder of any of examples 24-35, wherein the up-looking metrology system comprises an up-looking interferometer.

[0173] Example 37: The die bonder of example 36, wherein the die bonder is further configured to: determine a phase of diffracted beams from an illumination of the alignment mark on the component using the up-looking interferometer; and determine, based on the phase of the diffracted beams from the alignment mark on the component, a position of the alignment mark of the component relative to the up-looking interferometer.

[0174] Example 38: The die bonder of example 36 or 37, wherein the up-looking interferometer and the down-looking interferometer comprise position-sensing detectors (PSD).

[0175] Example 39: The die bonder of any of examples 24-38, wherein the die bonder is further configured to: move, using the drive system, the component such that another alignment mark of the component is within the field-of-view of the up-looking metrology system; determine a position of the other alignment mark of the component relative to the up-looking metrology system; determine, based on the determined position of the alignment mark on the component and the determined position of the other alignment mark of the component, a rotation for the component; move, using the drive system and / or the interferometer drive system, the down-looking interferometer such that another alignment mark of the substrate proximate the bond location is within the field-of-view of the down-looking interferometer; determine a phase of diffracted beams from an illumination of the other alignment mark on the substrate using the down-looking interferometer; determine, based on the phase of the diffracted beams from the other alignment mark on the substrate, a position of the other alignment mark of the substrate relative to the down-looking interferometer; determine, based on the determined position of the alignment mark on the substrate and the determined position of the other alignment mark of the substrate, a rotation for the substrate; determine the correction vector for the component based further on the determined position of the other alignment mark of the component; determine the correction vector for the substrate based further on the determined position of the other alignment mark of the substrate; and determine the final position based further on the rotation for the component and the rotation for the substrate.

[0176] Example 40: The die bonder of any of examples 24-39, wherein the diffracted beams comprise at least two orders of a negative one, zero, or positive one diffracted beams.

[0177] Example 41 : The die bonder of any of examples 24-40, wherein the down-looking interferometer is configured such that a wavelength and incidence angle of an incident beam is matched to a periodicity of the alignment mark effective to diffract a -1 or 1st order according to Littrow's geometry.

[0178] Example 42: The die bonder of any of examples 24-41, wherein the die bonder is further configured to illuminate the alignment mark of the substrate using Gaussian beams with dominant modes TEM00 and a beam parameter M squared that is less than 1.5.

[0179] Example 43: The die bonder of any of examples 24-42, wherein the die bonder is further configured to determine the position of the alignment mark of the substrate when the alignment mark is than or equal to 20 micrometers by 20 micrometers.

[0180] Example 44: The die bonder of any of examples 24-43, wherein the down-looking interferometer is configured with a working distance of at least 10 mm.

[0181] Example 45: The die bonder of any of examples 24-44, wherein the die bonder is further configured to illuminate the alignment mark of the substrate with beams having coherence lengths greater than one tenth of a millimeter.

[0182] Example 46: The die bonder of any of examples 24-45, wherein the die bonder is further configured to accept a feature size of the alignment mark on the substrate that is less than 1 micrometer.

[0183] Example 47: The die bonder of example 46, wherein the feature size of the alignment mark on the substrate is a width of a line of the alignment mark on the substrate.

[0184] Example 48: The die bonder of any of examples 24-47, wherein the alignment mark on the substrate comprises a pattern of lines or contact pads.

[0185] Example 49: The die bonder of any of examples 24-48, wherein the alignment mark on the substrate is aligned with two linearly independent axes.

[0186] Example 50: A method of determining a corrected target position for a component at a bond location of a substrate, the method comprising: establishing a spatial relationship between the component and an up-looking metrology system such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system; determining a position of the component alignment mark relative to the up -looking metrology system; determining, based on the position of the component alignment mark, a component correction vector; establishing a spatial relationship between the substrate and a down-looking interferometer such that a substrate alignment mark of the substrate proximate the bond location is within a sensitivity range of the down-looking interferometer; determining a phase of at least one diffracted beam from an illumination of the substrate alignment mark using the down-looking interferometer; determining, based on the phase of the diffracted beam from the substrate alignment mark, a position of the substrate alignment mark relative to the downlooking interferometer; determining, based on the position of the substrate alignment mark, asubstrate correction vector; and determining the corrected target position based on the component correction vector and based on the substrate correction vector.

[0187] Example 51 : The method of example 50, wherein the establishing the spatial relationship between the substrate and the down-looking interferometer has an accuracy within a periodicity of the substrate alignment mark.

[0188] Example 52: The method of example 50 or 51, further comprising generating a mapping between the up-looking metrology system and the down-looking interferometer, wherein the determining the corrected target position is based further on the mapping.

[0189] Example 53: The method of example 52, wherein the generating the mapping comprises: establishing a spatial relationship between the down-looking interferometer and the up-looking metrology system such that the down-looking interferometer and the up-looking metrology system are aligned; and establishing a spatial relationship between a calibration plate, the down-looking interferometer, and the up-looking metrology system such that the calibration plate is between the down-looking interferometer and the up-looking metrology system.

[0190] Example 54: The method of example 53, wherein the calibration plate comprises at least one calibration mark that is configured to be viewed by the up-looking metrology system and the down-looking interferometer concurrently.

[0191] Example 55: The method of any of examples 50-54, wherein the up-looking metrology system comprises an up-looking interferometer.

[0192] Example 56: The method of example 55, further comprising determining a phase of a diffracted beam from an illumination of the component alignment mark using the up-looking interferometer, wherein the position of the component alignment mark is based on the phase of the diffracted beam from the component alignment mark.

[0193] Example 57: The method of example 56, wherein at least one of the up-looking interferometer and the down-looking interferometer comprise position-sensing detectors (PSD).

[0194] Example 58: The method of any of any of examples 50-57, wherein: the method further comprises: establishing another spatial relationship between the component and the up- looking metrology system such that another component alignment mark of the component is within the field-of-view or sensitivity range of the up-looking metrology system; determining a position of the other component alignment mark relative to the up-looking metrology system;determining, based on the position of the component alignment mark and the position of the other component alignment mark, a component rotation; establishing another spatial relationship between the substrate and the down-looking interferometer such that another substrate alignment mark of the substrate proximate the bond location is within the sensitivity range of the downlooking interferometer; determining a phase of a diffracted beam from an illumination of the other substrate alignment mark using the down-looking interferometer; determining, based on the phase of the diffracted beam from the other substrate alignment mark, a position of the other substrate alignment mark relative to the down-looking interferometer; and determining, based on the position of the substrate alignment mark and the position of the other substrate alignment mark, a substrate rotation; the component correction vector is based further on the position of the other component alignment mark; the substrate correction vector is based further on the position of the other substrate alignment mark; and the determining the corrected target position is based further on the component rotation and the substrate rotation.

[0195] Example 59: The method of any of examples 50-58, wherein the diffracted beam comprises at least two orders of a negative one, zero, or positive one diffracted beams.

[0196] Example 60: The method of any of examples 50-59, wherein the down-looking interferometer is configured such that a wavelength and incidence angle of an incident beam is matched to a periodicity of the substrate alignment mark effective to diffract a -1 or 1st order according to Littrow's geometry.

[0197] Example 61 : The method of any of examples 50-60, wherein the illumination of the substrate alignment mark comprises illuminating the substrate alignment mark using Gaussian beams with dominant modes TEM00 and a beam parameter M squared that is less than 1.5.

[0198] Example 62: The method of any of examples 50-61, wherein: the substrate alignment mark has a corresponding area less than or equal to 400 micrometers squared; or a working distance of the down-looking interferometer is at least 5 mm.

[0199] Example 63: The method of any of examples 50-62, wherein the illumination of the substrate alignment mark comprises illuminating the substrate alignment mark with beams having coherence lengths greater than one tenth of a millimeter.

[0200] Example 64: The method of any of examples 50-63, wherein a feature size of the substrate alignment mark is less than 1 micrometer.

[0201] Example 65: The method of example 64, wherein the feature size of the alignment mark on the substrate is a width of a line of the alignment mark on the substrate.

[0202] Example 66: The method of any of examples 50-65, wherein the substrate alignment mark comprises a pattern of periodic lines or contact pads which diffract one or more incident beams.

[0203] Example 67: The method of any of examples 50-66, wherein the substrate alignment mark is aligned with two linearly independent axes.

[0204] Example 68: A die bonder comprising: a component supply system configured to supply a component; a substrate supply system configured to supply a substrate; a drive system; a down-looking interferometer; and an up-looking metrology system, wherein the die bonder is configured to: establish, via the drive system, a spatial relationship between the component and the up-looking metrology system such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system; determine a position of the component alignment mark relative to the up -looking metrology system; determine, based on the position of the component alignment mark, a component correction vector; establish, via the drive system, a spatial relationship between the substrate and the downlooking interferometer such that a substrate alignment mark of the substrate proximate a bond location of the substrate is within a sensitivity range of the down-looking interferometer; determining a phase of at least one diffracted beam from an illumination of the substrate alignment mark using the down-looking interferometer; determine, based on the phase of the diffracted beam from the substrate alignment mark, a position of the substrate alignment mark relative to the down-looking interferometer; determine, based on the position of the substrate alignment mark, a substrate correction vector; and determine a corrected target position for the component at the bond location of the substrate based on the component correction vector and based on the substrate correction vector.

[0205] Example 69: A method of determining a component correction vector for a component within a die bonder, the method comprising: releasably attaching the component to a bond head of the die bonder; positioning the bond head such that a component alignment mark ofthe component is within a sensitivity range of an up-looking interferometer of the die bonder; determining a phase of at least one diffracted beam from an illumination of the component alignment mark using the up-looking interferometer; determining, based on the phase of the diffracted beam from the component alignment mark, a position of the component alignment mark relative to the up-looking interferometer; and determining a component correction vector for the component based on the position of the component alignment mark.

[0206] The terminology used herein is for the purpose of describing particular implementations, embodiments, and / or examples only and is not intended to be limiting of this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes,” “comprises,” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Further, the terms up, upper, down, lower, above, below, left, right, forward, rearward, and the like are intended to be understood in the context of the representations described and illustrated above so that a wearable device may have such an orientation in reference to the frame or to various elements as supported by the frame or as illustrated in the drawing figures.

[0207] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements, if any, in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present disclosure has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to this disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of this disclosure. The various embodiments were chosen and described in order to best explain the principles of this disclosure and the practical application, and to enable others of ordinary skill in the art to understand this disclosure for various embodiments with various modifications as are suited to the particular use contemplated.LIST OF REFERENCE NUMERALS USED100 component102 bond location104 substrate106 die bonder108 bond head110 down-looking interferometer111 down-looking sensitivity range112 up-looking metrology system113 up-looking sensitivity space114 component alignment mark116 contact pads 00 die edge 02 seal ring500 substrate alignment mark800 method901 alignment mark features902 illumination spot904 incident beam906 reflected beam908 diffracted beam910 beam splitter912 mirror1000 photodetectors1100 light source1102 collimator lens1104 focusing lens1106 reflection lens1108 diffraction lens1200 camera1300 calibration plate1302 calibration alignment mark1304 grating portion1306 fiducials1600 diffractive optical element (DOE)1602 DOE diffracted incident beam1604 substrate alignment mark reflected beam1606 substrate alignment mark reflected beam1607 DOE back diffracted beam1608 polarization beam splitter1610 polarization controller1700 phase component1800 system1802 processing unit1804 computer-readable storage medium1806 target position determination module1808 instructions1810 data

Claims

CLAIMS1. A method of determining a corrected target position for a component at a bond location of a substrate, the method comprising: establishing a spatial relationship between the component and an up-looking metrology system such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system; determining a position of the component alignment mark relative to the up- looking metrology system; determining, based on the position of the component alignment mark, a component correction vector; establishing a spatial relationship between the substrate and a down-looking interferometer such that a substrate alignment mark of the substrate proximate the bond location is within a sensitivity range of the down-looking interferometer; determining a phase of at least one diffracted beam from an illumination of the substrate alignment mark using the down-looking interferometer; determining, based on the phase of the diffracted beam from the substrate alignment mark, a position of the substrate alignment mark relative to the down-looking interferometer; determining, based on the position of the substrate alignment mark, a substrate correction vector; and determining the corrected target position based on the component correction vector and based on the substrate correction vector.

2. The method of claim 1, wherein the establishing the spatial relationship between the substrate and the down-looking interferometer has an accuracy within a periodicity of the substrate alignment mark.

3. The method of claim 1, further comprising generating a mapping between the up-looking metrology system and the down-looking interferometer, wherein the determining the corrected target position is based further on the mapping.

4. The method of claim 3, wherein the generating the mapping comprises: establishing a spatial relationship between the down-looking interferometer and the up-looking metrology system such that the down-looking interferometer and the up- looking metrology system are aligned; and establishing a spatial relationship between a calibration plate, the down-looking interferometer, and the up-looking metrology system such that the calibration plate is between the down-looking interferometer and the up-looking metrology system.

5. The method of claim 4, wherein the calibration plate comprises at least one calibration mark that is configured to be viewed by the up-looking metrology system and the down-looking interferometer concurrently.

6. The method of claim 1, wherein the up-looking metrology system comprises an up-looking interferometer.

7. The method of claim 6, further comprising determining a phase of a diffracted beam from an illumination of the component alignment mark using the up-looking interferometer, wherein the position of the component alignment mark is based on the phase of the diffracted beam from the component alignment mark.

8. The method of claim 7, wherein at least one of the up-looking interferometer and the down-looking interferometer comprise position-sensing detectors (PSD).

9. The method of claim 1, wherein: the method further comprises:establishing another spatial relationship between the component and the up-looking metrology system such that another component alignment mark of the component is within the field-of-view or sensitivity range of the up-looking metrology system; determining a position of the other component alignment mark relative to the up-looking metrology system; determining, based on the position of the component alignment mark and the position of the other component alignment mark, a component rotation; establishing another spatial relationship between the substrate and the down-looking interferometer such that another substrate alignment mark of the substrate proximate the bond location is within the sensitivity range of the downlooking interferometer; determining a phase of a diffracted beam from an illumination of the other substrate alignment mark using the down-looking interferometer; determining, based on the phase of the diffracted beam from the other substrate alignment mark, a position of the other substrate alignment mark relative to the down-looking interferometer; and determining, based on the position of the substrate alignment mark and the position of the other substrate alignment mark, a substrate rotation; the component correction vector is based further on the position of the other component alignment mark; the substrate correction vector is based further on the position of the other substrate alignment mark; and the determining the corrected target position is based further on the component rotation and the substrate rotation.

10. The method of claim 1, wherein the diffracted beam comprises at least two orders of a negative one, zero, or positive one diffracted beams.

11. The method of claim 1 , wherein the down-looking interferometer is configured such that a wavelength and incidence angle of an incident beam is matched to a periodicity of the substrate alignment mark effective to diffract a -1 or 1st order according to Littrow's geometry.

12. The method of claim 1 , wherein the illumination of the substrate alignment mark comprises illuminating the substrate alignment mark using Gaussian beams with dominant modes TEMOO and a beam parameter M squared that is less than 1.5.

13. The method of claim 1, wherein: the substrate alignment mark has a corresponding area less than or equal to 400 micrometers squared; or a working distance of the down-looking interferometer is at least 5 mm.

14. The method of claim 1 , wherein the illumination of the substrate alignment mark comprises illuminating the substrate alignment mark with beams having coherence lengths greater than one tenth of a millimeter.

15. The method of claim 1, wherein a feature size of the substrate alignment mark is less than 1 micrometer.

16. The method of claim 15, wherein the feature size of the alignment mark on the substrate is a width of a line of the alignment mark on the substrate.

17. The method of claim 1, wherein the substrate alignment mark comprises a pattern of periodic lines or contact pads which diffract one or more incident beams.

18. The method of claim 1, wherein the substrate alignment mark is aligned with two linearly independent axes.

19. A die bonder comprising: a component supply system configured to supply a component; a substrate supply system configured to supply a substrate; a drive system; a down-looking interferometer; and an up-looking metrology system, wherein the die bonder is configured to: establish, via the drive system, a spatial relationship between the component and the up-looking metrology system such that a component alignment mark of the component is within a field-of-view or sensitivity range of the up-looking metrology system; determine a position of the component alignment mark relative to the up- looking metrology system; determine, based on the position of the component alignment mark, a component correction vector; establish, via the drive system, a spatial relationship between the substrate and the down-looking interferometer such that a substrate alignment mark of the substrate proximate a bond location of the substrate is within a sensitivity range of the down-looking interferometer; determining a phase of at least one diffracted beam from an illumination of the substrate alignment mark using the down-looking interferometer; determine, based on the phase of the diffracted beam from the substrate alignment mark, a position of the substrate alignment mark relative to the downlooking interferometer; determine, based on the position of the substrate alignment mark, a substrate correction vector; and determine a corrected target position for the component at the bond location of the substrate based on the component correction vector and based on the substrate correction vector.

20. A method of determining a component correction vector for a component within a die bonder, the method comprising: releasably attaching the component to a bond head of the die bonder; positioning the bond head such that a component alignment mark of the component is within a sensitivity range of an up-looking interferometer of the die bonder; determining a phase of at least one diffracted beam from an illumination of the component alignment mark using the up-looking interferometer; determining, based on the phase of the diffracted beam from the component alignment mark, a position of the component alignment mark relative to the up-looking interferometer; and determining a component correction vector for the component based on the position of the component alignment mark.

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