Alignment system for aligning a measuring device and method relating thereto

Abstract

The present disclosure relates to alignment or calibration techniques for aligning at least one down-looking measurement device and at least one up-looking measurement device relative to each other. In particular, the present disclosure relates to devices and computer-implemented methods for aligning at least one down-looking measurement device and at least one up-looking measurement device relative to each other, for example but not limited to use in mounting components on a substrate.

Description

[0001] Cross-references to related applications

[0002] This international application claims priority to DE 10 2023 133 898.6, filed on December 4, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to alignment or calibration techniques for aligning at least one downward-looking measuring device and at least one upward-looking measuring device relative to each other. In particular, this disclosure relates to a device and computer-implemented method for aligning at least one downward-looking measuring device and at least one upward-looking measuring device relative to each other, for example, for mounting components on a substrate.

[0004] Background and Existing Technology

[0005] In the semiconductor industry, components (typically electronic or optical, particularly semiconductor dies and flip chips) are mounted onto substrates using automated processes. This automated mounting is also known in the field as a bonding or assembly process and is performed using high-tech equipment called chip bonders or pick-and-place machines (die mounters). For example, using chip bonding equipment, components in the form of semiconductor dies, flip chips, micromechanical, micro-optical, and electro-optical components, and the like, are deposited onto substrates such as leadframes, printed circuit boards, ceramics, wafers, etc., and mechanically and electrically bonded.

[0006] The component is picked up from the removal position by the bonding head, particularly held by vacuum or electrostatic force, moved to the substrate position, and deposited on the substrate at a precisely defined location. The bonding head is part of a pick-and-place device or system that enables the bonding head to move precisely in at least three spatial directions. To accurately position the component on the substrate, the precise position of the component held by the bonding head relative to the bonding head positioning axis and the precise position of the substrate must be determined.

[0007] Commercially available chip bonding equipment achieves a positioning accuracy of 2 to 3 micrometers while processing 4,000 to 8,000 chips per hour under optimal conditions. They employ various measuring devices, such as an upper-view vision device (or component vision device) to position the chip assembly on the bonding head; and a lower-view vision device (or substrate vision device) to position the bonding location on the substrate where the chip assembly needs to be positioned and bonded. To accurately place the chip assembly at the bonding location, complex methods are required for calibrating the fields of view of the lower-view and upper-view measuring devices. For certain system configurations and to achieve even higher chip assembly placement, it is advantageous for machine software to correlate the fields of view of the lower-view and upper-view measuring devices. This relationship between the measurement systems of the two devices is determined during calibration or alignment procedures.

[0008] In the prior art, various known processes are implemented to establish this relationship between measurement systems of various measuring devices. When implementing a measuring device, the most common approach is to use a reference element or calibration target containing reference marks. The measuring device can position the reference marks and calculate a common coordinate system, or "register" the measuring devices relative to each other.

[0009] These known alignment techniques are susceptible to various optical errors, such as positioning the reference mark under different optical conditions. Such different optical conditions can occur when the relative position of the reference element and one of the measuring devices changes between positioning the reference mark and the measuring device.

[0010] Positioning errors can also occur when the operating distance of the measuring device from the calibration target during calibration differs from its distance from the component or substrate during processing. This difference in operating distance can lead to errors due to mechanical tolerances or tilt of the calibration target relative to the optical axis of the measuring device.

[0011] Furthermore, refocusing of the measuring device during alignment or calibration steps can cause similar errors.

[0012] For example, the tilt of the reference element relative to the optical axis of the measuring device can cause optical errors due to the refractive index of the reference element. These drawbacks adversely affect the correct alignment of the two measuring device systems relative to each other. While these drawbacks are acceptable and tolerable within the error budget of current pick-and-place devices, they are unacceptable for systems with far more stringent accuracy requirements (e.g., 200 nm and below at a standard deviation of 3 sigma). Such higher precision requirements are necessary for near-future high-end packaging to significantly increase the density of electrical connectors between the chip and the substrate.

[0013] Furthermore, the calibrated relationship between two measuring devices is prone to change due to time-dependent variations in the equipment, such as thermal drift. This effect is known as calibration aging. Existing equipment combats this effect through recalibration procedures that involve periodically running at least a portion of a basic calibration routine and / or performing it at certain trigger points (e.g., after a certain period of time, after a warm-up cycle, or after operator interaction). This approach typically negatively impacts system throughput and / or placement accuracy when recalibration is performed too frequently or too infrequently. There is no direct method to detect calibration aging to ensure that the calibrated relationship remains within a given tolerance while maintaining high throughput.

[0014] Therefore, one object of this disclosure is to provide an improved alignment system and alignment method that allows for higher placement accuracy than the prior art while maintaining high throughput. Summary of the Invention

[0015] According to a first example of this disclosure, an alignment system is provided for aligning at least one downward-looking measuring device and at least one upward-looking measuring device relative to each other. The alignment system includes at least one upward-looking measuring device having at least one upward-looking focal plane and an upward-looking field of view pointing toward at least one second downward-looking measuring device; wherein the at least one downward-looking measuring device has at least one downward-looking focal plane and a downward-looking field of view pointing toward the at least one upward-looking measuring device; and a reference element including at least one first mark; wherein, in a first alignment state, the alignment system is configured to position the reference element within the upward-looking focal plane and the downward-looking focal plane, such that the at least one first mark is oriented in the at least one upward-looking focal plane, and the at least one downward-looking measuring device is configured to focus on the at least one first mark in a first focusing state; and the alignment system is configured to align the at least one downward-looking focal plane of the at least one downward-looking measuring device with the upward-looking focal plane of the at least one upward-looking measuring device, at least based on the first focusing state.

[0016] Therefore, optical aberrations, such as errors in the correct position of individual reference marks under different optical conditions, can be largely eliminated. This enables more precise alignment or calibration of the two measuring device systems, allowing implementation in systems with more stringent accuracy requirements.

[0017] In another advantageous example, the alignment system is configured to align the at least one lower focal plane of the at least one lower focal plane of the at least one lower focal plane of the at least one upper focal plane of the at least one upper focal plane with the at least one lower focal plane of the at least one lower focal plane, based on the first focusing state and one or more parameters selected from the optical characteristics of the reference element, the thickness of the reference element, and the depth of focus of the at least one lower focal plane measuring device.

[0018] In a more precise example, the alignment system further includes at least one second mark oriented in the at least one upper focal plane, and in the first alignment state, the at least one lower measuring device is configured to focus on the at least one second mark, and in the second alignment state, the alignment system is configured to position the reference element outside the lower field of view, and the at least one lower measuring device is configured to focus on the at least one second mark in the second focusing state, wherein the alignment system is configured to align the at least one lower focal plane of the at least one lower measuring device with the upper focal plane of the at least one upper measuring device based on both the first focusing state and the second focusing state.

[0019] Thus, the downward-looking measuring device is aligned and will know the position of, for example, a tool holder with a semiconductor die with high precision, thereby ensuring higher placement accuracy compared to existing technologies.

[0020] In another advantageous example, the alignment system further includes a support frame configured to be fixed in position relative to the at least one upward-looking measuring device and configured to support the reference element in the first alignment state.

[0021] Preferably, the second mark is mounted on the support frame to further ensure accurate and repeatable alignment.

[0022] For alignment purposes, the alignment system is configured to transform the first focus position of the at least one second mark acquired by the at least one downward-looking measuring device in the first alignment state to the second focus position of the at least one second mark acquired by the at least one downward-looking measuring device in the second alignment state.

[0023] In particular, the transformation may include transforming the first focus position of the at least one first marker to the second focus position of the at least one first marker. In one example, the transformation may be performed computationally, preferably by translation in a plane perpendicular to the first longitudinal axis and / or by rotation about the first longitudinal axis. Other transformation techniques may include rotation, shearing, tilting, or the use of higher-order Zernike polynomials.

[0024] In an advantageous example, the alignment system includes at least one third mark, which, when viewed in a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device and the at least one second upward-looking measuring device, is positioned at a distance from the upward-looking focal plane and on a first side of the upward-looking focal plane. Optionally, the alignment system may further include at least one frame component and / or an additional support frame component, the frame component and / or the additional support frame component containing at least one third mark.

[0025] In an advantageous example, the alignment system includes at least one fourth mark, which, when viewed in a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device and the at least one second upward-looking measuring device, is positioned at a distance from the upward-looking focal plane and on a second side opposite to the upward-looking focal plane. Optionally, the alignment system may further include at least one frame component and / or an additional support frame component, the frame component and / or the additional support frame component containing at least one third mark and / or at least one fourth mark.

[0026] The presence of additional third and fourth marks (optionally mounted on the support frame, and particularly present on separate frame components not containing the first and second marks) allows for correction of changes in the calibrated relationship (X, Y, rotZ) between the two measuring device systems due to thermal drift (calibration aging). When used to detect calibration aging, the third and fourth marks offer advantages over the second and third marks, largely due to the refraction of the separate frame components, where a degree of tilt does not significantly negatively impact alignment accuracy.

[0027] In an advantageous example, the alignment system includes at least one fifth mark oriented in the at least one superior focal plane. Optionally, the alignment system may also include at least one frame component and / or an additional support frame component containing at least one third mark and / or at least one fourth mark and / or at least one fifth mark.

[0028] Optionally, the alignment or calibration of the at least one downward-looking measuring device can therefore be further enhanced by using at least one fifth mark oriented in the at least one upward-looking focal plane.

[0029] In a preferred embodiment, the at least one frame component and / or additional support frame component is made of a material having a refractive index n in the range of 1.9 to 2.1, particularly 1.95 to 2.05, more particularly 1.975 to 2.025, even more particularly 1.99 to 2.01 and even more particularly 1.995 to 2.005.

[0030] If the at least one upward-looking measuring device is configured to additionally determine the initial position of the at least one fourth mark and / or the at least one fifth mark in the first alignment state, and to determine the subsequent position of the at least one fourth mark and / or the at least one fifth mark in the second alignment state, then the aforementioned calibration aging effect can be highly corrected; and the alignment system is configured to realign the at least one downward-looking focal plane of the at least one downward-looking measuring device with the at least one upward-looking focal plane of the at least one upward-looking measuring device based on one or more initial positions and / or one or more subsequent positions thus determined.

[0031] Advantageously, the reference element is coplanar. Alternatively, the reference element may be highly transmissive to the at least one downward-looking measuring device.

[0032] It should be noted that, in the improved example, in either the first alignment state or the second alignment state, the at least one downward-looking measuring device is configured to focus in the first focusing state and / or the second focusing state by refocusing its at least one downward-looking focal plane.

[0033] Alternatively, the at least one downward-looking measuring device may further include a displacement module configured to move the at least one downward-looking measuring device from the first focusing state toward the second focusing state at least along a direction substantially parallel to the common longitudinal axis of the at least one second downward-looking measuring device and the at least one second upward-looking measuring device.

[0034] The common vertical axis can be the Z-axis of the XYZ coordinate system.

[0035] This disclosure also relates to a computer-implemented method for aligning at least one downward-looking measuring device and at least one upward-looking measuring device relative to each other, the alignment method comprising at least the following steps: i) orienting at least one upward-looking measuring device having an upward-looking focal plane and an upward-looking field of view toward at least one second downward-looking measuring device; ii) orienting at least one downward-looking measuring device having at least one downward-looking focal plane and a downward-looking field of view toward the at least one upward-looking measuring device; iii) in a first alignment state, mounting a reference element including at least one first mark within the upward-looking field of view and the downward-looking field of view; and iv-1) orienting the at least one first mark in the upward-looking focal plane; v) in a first focusing state, focusing the at least one downward-looking measuring device on the at least one first mark; vi) aligning the downward-looking focal plane of the at least one downward-looking measuring device with the upward-looking focal plane of the at least one upward-looking measuring device based on the first focusing state.

[0036] This method effectively cancels out optical aberrations such as the tilt of the reference element and the shift of the focal plane due to its thickness. Therefore, it enables more precise alignment or calibration of one or more measuring devices relative to each other, allowing implementation in systems with far more stringent accuracy requirements.

[0037] Further improvements in alignment are achieved through alignment step vi), based on the first focusing state and one or more parameters selected from the optical properties of the reference element, the thickness of the reference element, and the depth of focus of the at least one downward-looking measuring device. Optical properties may be affected by material, refractive index, or similar factors.

[0038] It may be advantageous if the computer-implemented method further includes the following steps: iv-2) orienting at least one second mark in the at least one upper focal plane; iv-3) focusing the at least one lower measuring device on the at least one second mark; vii) in a second alignment state, moving the reference element out of the upper and lower fields of view; and viiii) in a second focusing state, focusing the at least one lower measuring device on the at least one second mark; and vi-2) aligning the second focal plane of the at least one lower measuring device with the upper focal plane of the at least one upper measuring device based on the first and second focusing states.

[0039] If alignment step vi-2) includes step ix): transforming the first focus position of the at least one first mark obtained by the at least one downward-looking measuring device in the first focus state to the second focus position of the at least one first mark obtained by the at least one downward-looking measuring device in the second focus state, it may be advantageous.

[0040] If the transformation step (ix) includes: transforming the first focal position to the second focal position by translation in a plane perpendicular to the common longitudinal axis of the at least one second lower-view measuring device and the at least one second upper-view measuring device and / or by rotation about the common longitudinal axis, it may be advantageous.

[0041] If the alignment system includes at least one third mark, which is positioned at a distance from the upper focal plane and on a first side of the upper focal plane when viewed in a direction parallel to the common longitudinal axis of the at least one second lower-view measuring device and the at least one second upper-view measuring device, and the method includes the further steps of: determining an initial position of the at least one third mark with the at least one lower-view measuring device in a first focusing state and determining a subsequent position of the at least one third mark in a second focusing state; and realigning the lower focal plane of the at least one lower-view measuring device with the upper focal plane of the at least one upper-view measuring device based on one or more initial positions and / or one or more subsequent positions thus determined, it may be advantageous.

[0042] If the alignment system further includes at least one fourth mark, which is positioned at a distance from and on a second side opposite to the upper focal plane when viewed in a direction parallel to the common longitudinal axis of the at least one second lower-view measuring device and the at least one second upper-view measuring device, and the method includes the further steps of: determining an initial position of the at least one fourth mark in a first focusing state and a subsequent position of the at least one fourth mark in a second focusing state using the at least one upper-view measuring device; and realigning the lower focal plane of the at least one lower-view measuring device with the upper focal plane of the at least one upper-view measuring device based on one or more initial positions and / or one or more subsequent positions of the at least one third mark and / or the at least one fourth mark thus determined, it may be advantageous.

[0043] If the alignment system includes at least one fifth mark oriented in the at least one upper focal plane, and the method includes the further steps of: determining an initial position of the at least one fifth mark in a first focusing state and determining a subsequent position of the at least one fifth mark in a second focusing state using the at least one upper measuring device; and realigning the lower focal plane of the at least one lower measuring device with the upper focal plane of the at least one upper measuring device based on one or more initial positions and one or more subsequent positions of the at least one second mark and / or the at least one fifth mark thus determined.

[0044] This disclosure also relates to a computer program or product that includes instructions that, when executed by a computer (particularly a computer associated with an alignment system according to this disclosure), cause the computer to perform the steps of a computer-implemented method according to this disclosure.

[0045] Similarly, this disclosure also relates to a computer-readable storage medium comprising instructions that, when executed by a computer (particularly a computer associated with an alignment system according to this disclosure), cause the computer to perform the steps of a computer-implemented method according to this disclosure. Attached Figure Description

[0046] This disclosure will now be discussed with reference to the accompanying drawings, in which:

[0047] Figure 1 A first pickup and placement device using alignment technology is schematically depicted;

[0048] Figure 2 Depicting and Figure 1 The optical errors related to the alignment technique shown;

[0049] Figures 3 to 12 Various aspects of an example alignment system according to this disclosure are described;

[0050] Figures 13 to 18 Depicted in the first alignment position and the second alignment position Figures 3 to 12 Further aspects of the alignment system shown;

[0051] Figures 19 to 22 Depicted in the first alignment position and the second alignment position Figures 3 to 12 Alternative aspects of the alignment system shown;

[0052] Figures 23 to 24 A second pickup and placement device using the alignment technique according to this disclosure is described;

[0053] Figure 24 A third pickup and placement device using alignment technology according to this disclosure is described.

[0054] Detailed description of this disclosure

[0055] In order to properly understand this disclosure, in the following detailed description, the corresponding elements or parts of this disclosure will be indicated by the same reference numerals in the accompanying drawings.

[0056] Figure 1 A first embodiment of the pick-and-place device 10 (first pick-and-place device) is depicted schematically and exemplaryly. The first pick-and-place device 10 interacts with a substrate 20, and a plurality of semiconductor dies 211, 212, 213 are mounted at specific locations on the substrate 20, and in optimal conditions, a positioning accuracy of 2 to 3 micrometers (3-sigma standard deviation) can be achieved.

[0057] The first pick-and-place device 10 is implemented with at least one first downward-looking measuring device 12 and at least one first upward-looking measuring device 11, which are precisely aligned relative to each other and relative to the substrate 20. Precise alignment ensures accurate positioning of the semiconductor dies 211, 212, 213 at desired locations on the substrate 20. For placement and bonding at desired locations on the substrate 20, the corresponding semiconductor die 213 is depicted as being held by a first embodiment of the bonding head 13 (the first bonding head).

[0058] In the context of this disclosure, it should be understood that a measuring device refers to a specialized apparatus for performing various precise measurements, inspections, and quality control of objects or components. In this application, a non-limiting example of a measuring device used to implement this disclosure may be a vision device. A vision device may also be implemented as one or more components of a camera.

[0059] The terms "upward view" and "downward view" are used to describe the common orientation of the measuring apparatus shown in the accompanying drawings. However, these measuring apparatuses can be used in any other orientation and are interchangeable in some configurations.

[0060] The first upward-viewing measuring device 11 has a field of view 1120 facing the substrate 20 and the first downward-viewing measuring device 12. Similarly, the first downward-viewing measuring device 12 has a field of view 1220 facing the substrate 20 and the first upward-viewing measuring device 11.

[0061] The sensing and / or imaging performed by the first upward-looking measuring device 11 is represented by the first upward-looking imaging ray 1111 and the second upward-looking imaging ray 1112. The sensing and / or imaging performed by the first downward-looking measuring device 12 is represented by the first downward-looking imaging ray 1211 and the second downward-looking imaging ray 1212.

[0062] To position the first bonding head 13 and the semiconductor die 213 correctly above their placement positions on the substrate 20, the bonding positions on the substrate 20 need to be determined. For the semiconductor dies 211, 212, and 213 to be accurately placed at their bonding positions, the machine software must be able to correlate the field of view 1220 of the first downward-looking measuring device 12 and the field of view 1120 of the first upward-looking measuring device 11. This relationship between the two measuring device systems is typically measured during the alignment or calibration process.

[0063] Various methods can be implemented to establish this relationship between the measuring devices, such as the relationship between the first upward-looking measuring device 11 and the first downward-looking measuring device 12. A common method is to use a reference element or calibration target containing reference marks. Both first measuring devices 11, 12 are arranged to position the reference marks and calculate a common coordinate system and / or “register” the measuring devices 11, 12 with respect to one or more of their relative positions.

[0064] Figure 2 A first embodiment of reference element 14 (first reference element) is shown. The first reference element 14 includes one or more markers 1411. As depicted, the markers 1411 are on the top side of the first reference element 14, facing the first downward-looking measuring device 12, or on the bottom side of the first reference element 14, facing the first upward-looking measuring device 11. Both first measuring devices 11, 12 are arranged to position the markers 1411 and establish one or more relative positions to each other in the X, Y, and / or rotZ directions of, for example, the XYZ coordinate system of the first pick-and-place device 10.

[0065] After establishing the alignment relationship between the two first measuring devices 11 and 12, the two first measuring devices 11 and 12 achieve proper and accurate alignment of the first bonding head 13 with respect to the expected bonding position on the substrate 20 by means of the bonding head mark 1311 mounted on the first bonding head 13, the die mark 2132 present on the semiconductor die 213, and the substrate mark mounted on the substrate 20.

[0066] Such alignment techniques are susceptible to various optical errors, such as positioning individual reference marks under different optical conditions. For example, such different optical conditions may occur when the relative position of the first reference element 14 with respect to one or more first measuring devices 11, 12 changes between the position measurements of the reference mark 1411 by the first measuring devices 11, 12.

[0067] Positioning errors can also occur when the operating distance from the measurement system to the calibration target during calibration differs from the operating distance to the component or substrate during processing. These differing operating distances can lead to errors, for example, due to mechanical tolerances and / or the tilt of the calibration target relative to the optical axis of one or more of the first measuring devices 11, 12.

[0068] These drawbacks may adversely affect the degree of proper alignment of the first measuring devices 11, 12 relative to each other. And while these drawbacks may be acceptable and tolerable within the error budget of the first pick-and-place device 10, they may be unacceptable for systems with far more stringent accuracy requirements, such as 200 nm and below at a 3-sigma standard deviation. For example, higher accuracy requirements are needed in hybrid bonding.

[0069] Additionally, factors such as thermal drift within the device can alter the calibrated relationship between the two first measuring devices 11, 12 (e.g., in the X, Y, and / or rotZ directions). This effect is known as calibration aging. The first pick-and-place device 10 can counteract this effect by periodically running one or more calibration routines, which run automatically and / or at certain trigger points (e.g., after a warm-up cycle or after operator interaction). However, there is no direct method to detect calibration aging.

[0070] As a solution to the aforementioned drawbacks, this disclosure proposes an improved alignment system and method for aligning at least one downward-looking measuring device and at least one upward-looking measuring device relative to each other. The improved alignment system and method described below can be implemented in many and various applications where a higher degree of alignment accuracy between the measuring devices is desired. For example, by appropriately modifying the pickup and placement devices (e.g., by appropriately modifying...). Figure 1 and Figure 2 The first pick-and-place device shown can implement the improved alignment system and method described below.

[0071] To properly understand the improved alignment system and method, the following detailed description will use [the relevant technology / method]. Figures 3 to 25 The same reference numerals are used to refer to corresponding elements or parts of this disclosure. The figures will be described in more detail after a general introduction to the key elements and parts shown in the various figures.

[0072] Figures 23 to 24 A second embodiment of a pick-and-place device (second pick-and-place device) is depicted, which, together with an improved alignment system 100, also implements a second embodiment of a bonding head 130 (second bonding head), the second bonding head being provided with a bonding head mark 13013 and a viewport 13075 of the second bonding head 130. Similarly, Figure 25 A third embodiment of a pick-and-place device (third pick-and-place device) is depicted, which, together with an improved alignment system 100, implements a second bonding head 130, the second bonding head being provided with a bonding head mark 13013 and a viewport 13075 of the second bonding head 130. As... Figure 23 and Figure 24 As shown, viewport 13075 is a channel designed to provide an optical path for the downward-looking measurement device 120 to focus on the bonding head mark 13013. For example, viewport 13075 may be a hollow space, or it may be made of a material that is highly transmissive to the imaging light of the downward-looking measurement device 120 in at least a portion of its area.

[0073] Figure 3 , 5Figures 7, 9, 11, 13, 15, 17, 19, 21, 23 and 25 show schematic side views of various examples of the improved alignment system 100 according to this disclosure. Figure 4 , 6 Figures 8, 10, 12, 14, 16, 18, 20, 22 and 24 show schematic top views of the respective fields of view of at least one second upward-looking measuring device 110 and at least one second downward-looking measuring device 120.

[0074] An improved alignment system 100 is adapted to align at least one second downward-looking measuring device 120 and at least one second upward-looking measuring device 110 relative to each other. The alignment system 100 includes at least one second upward-looking measuring device 110, which is provided with at least one upward-looking focal plane 11099 and an upward-looking field of view 11020. The upward-looking field of view 11020 of the at least one second upward-looking measuring device 110 faces the at least one second downward-looking measuring device 120. Similarly, the at least one second downward-looking measuring device 120 is provided with at least one downward-looking focal plane 12099 and a downward-looking field of view 12020. The downward-looking field of view 12020 of the at least one second downward-looking measuring device 120 faces the at least one second upward-looking measuring device 110.

[0075] Although the accompanying drawings schematically show at least one second upward-facing measuring device 110 and at least one second downward-facing measuring device 120 facing each other perpendicularly in a straight line, it should be noted that this orientation of the measuring devices facing each other is merely an example, and the relative positions of the second measuring devices do not necessarily imply a perpendicular facing relationship. However, it may be advantageous if at least one second upward-facing measuring device 110 and at least one second downward-facing measuring device 120 are both located on the Z-axis of the XYZ coordinate system in which the improved alignment system 100 operates.

[0076] The sensing and / or imaging performed by the at least one second upward-looking measuring device 110 is represented by a first upward-looking imaging ray 11011. The sensing and / or imaging performed by the at least one second downward-looking measuring device 120 is represented by a first downward-looking imaging ray 12011.

[0077] exist Figure 3 , 4During the selection steps of the improved alignment method shown in 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 19, and 20, the improved alignment system 100 includes a second embodiment of a reference element 310 (second reference element) disposed between the at least one second downward-looking measuring device 120 and the at least one second upward-looking measuring device 110. The second reference element 310 includes at least one first mark 315 on, at, or near a first surface 3101 of the second reference element 310. Suitable marks can be provided by modifying a chromium layer on the first surface of the glass plate. The improved alignment system 100 is arranged to position the at least one first mark 315 within the upward-looking field of view 11020 such that the first surface 3101 faces the at least one second upward-looking measuring device 110 and the at least one second upward-looking measuring device 110 can sense and / or image the at least one first mark 315. The second reference element 310 also includes a second surface 3102 opposite to the first surface 3101. An improved alignment system 100 is arranged to position the at least one first mark 315 within a downward field of view 12020, such that a second surface 3102 faces the at least one second downward-looking measuring device 120. For high-precision optical calibration, the second reference element 310 is preferably highly coplanar. The second reference element 310 has sufficient transmittance so that the at least one second downward-looking measuring device 120 can sense and / or image the at least one first mark 315. In a preferred example, the second reference element 310 is highly transmittant to the at least one second downward-looking measuring device 120. The alignment system 100 is configured to position the reference element 310 within the upper focal plane 11099 and in the lower focal plane 12099, such that the at least one first mark 315 is oriented in the at least one upper focal plane 11099, and the at least one lower measuring device 120 is configured to focus on the at least one first mark 315 in a first focusing state; and the alignment system 100 is configured to align the at least one lower focal plane 12099 of the at least one lower measuring device 120 with the upper focal plane 11099 of the at least one upper measuring device 110 based on at least the first focusing state.

[0078] like Figure 3As shown, the alignment system 100 may be provided with a control unit 711, which is adapted to properly control various components of the improved alignment system 100. For example, the control unit 711 is capable of controlling the at least one second upward-looking measuring device 110 via a first control line 7111 and the at least one second downward-looking measuring device 120 via a second control line 7112. For example, the control unit 711 may receive sensor data (e.g., image data) from one or more measuring devices 110, 120, perform one or more alignment processing steps, perform one or more realignment processing steps described below, generate appropriate control signals for controlling one or more measuring devices 110, 120, generate appropriate control signals for other components described herein, or any combination thereof. For clarity, the control unit 711 and control lines 7111, 7112 are not shown in other figures.

[0079] like Figure 21 As shown, the alignment system 100 may include at least one displacement module 740 arranged to displace the at least one second downward-looking measuring device 120 toward and / or away from the second reference element 310 in a generally positive and / or negative direction along the Z-axis. The degree of displacement may be predetermined and / or controlled such that the at least one first mark 315 is oriented in the downward-looking focal planes 12089, 12099. The degree of displacement may be controlled by a control unit 711 based on a control signal via a displacement control line 7401. Alternatively or additionally, the focus of the at least one second downward-looking measuring device 120 may be established in other ways, for example, by focusing the imaging lens of the at least one second downward-looking measuring device 120. For clarity, the at least one displacement module 740 and the displacement control line 7401 are not shown in the other figures.

[0080] More specifically, Figure 3 A schematic side view of a first operating state of the improved alignment system 100 according to this disclosure is depicted, the side view being generally located in the XZ plane, wherein the first operating state is also defined as a first alignment state. The at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120 are arranged generally along the YZ plane, facing each other and separated by a second reference element 310. The second reference element 310 extends in a generally XY plane between the at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120. The second reference element 310 is... Figure 3Viewed from the side, the second reference element 310 has a side extending generally along the XZ plane and a thickness 3199 extending generally along the Z-axis. The second reference element 310 has a first surface 3101 extending generally in the XY plane, with the first surface 3101 facing the at least one second upward-viewing measuring device 110. The second reference element 310 also has a second surface 3102 extending generally in the XY plane, with the second surface 3102 facing the at least one second downward-viewing measuring device 120. The average interval between the first surface 3101 and the second surface 3102 is the thickness 3199 of the second reference element 310. At least one first mark 315 is provided on the first surface side 3101 of the second reference element 310. In the depicted example, multiple marks 315 are provided on the first surface side 3101 of the second reference element 310.

[0081] Figure 4 It shows in Figure 3 A schematic top view of the respective fields of view of the at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120 in the first alignment state is shown. This schematic top view is depicted as being approximately located in the XY plane. At least one first mark 315 is shown at the first surface side 3101 of the second reference element 310. In the depicted example, a plurality of marks 315 are provided at the first surface side 3101 of the second reference element 310. Preferably, the plurality of marks 315 are arranged in a matrix array, such as... Figure 4 As shown in the example.

[0082] The upward field of view 11020 of the at least one second upward measuring device 110 extends substantially in the XY plane and faces the first surface 3101 of the second reference element 310. The downward field of view 12020 of the at least one second downward measuring device 120 extends substantially in the XY plane and faces the second surface 3102 of the second reference element 310.

[0083] exist Figure 3In the first alignment state shown, the second reference element 310 is positioned within the upward field of view 11020 of the at least one second upward measuring device 110, such that the at least one first mark 315 is oriented in the at least one upward focal plane 11099 of the at least one second upward measuring device 110. This ensures that the at least one second upward measuring device 110 has a focused view of the at least one first mark 315 of the second reference element 310. The second reference element 310 is also positioned within the downward field of view 12020 of the at least one second downward measuring device 120. To position the second reference element 310 within the upward field of view 11020 and within the downward field of view 12020, the improved alignment system 100 may be provided with a suitable positioning module. The positioning module may be controlled by a control unit 711. The positioning module is configured to position the second reference element 310 both within and outside the upward field of view 11020. The positioning module is also configured to position the second reference element 310 within the downward field of view 12020. Alternatively, in either the first alignment state and / or the second alignment state (described below), the at least one second downward-looking measuring device 120 can be focused in the first state by refocusing its at least one downward-looking focal plane 1289, 12099. As described below, the at least one second downward-looking measuring device 120 can also be focused in the second focusing state by refocusing its at least one downward-looking focal plane 12089, 12099.

[0084] Generally, the at least one downward-looking measuring device 120 is arranged to focus on at least two focal planes. The first focal plane 12089 of the at least one downward-looking measuring device 120 represents the initial focusing position, or the focusing position when no second reference element 310 affects the imaging of the at least one downward-looking measuring device 120. The second focal plane 12099 of the at least one downward-looking measuring device 120 represents the modified focusing position, or the focusing position when the second reference element 310 is present and the focusing is modified to correct for the imaging influence of the second reference element 310.

[0085] When in Figure 3 and Figure 4 In the first alignment state shown, the at least one first mark 315 of the second reference element 310 is more or less in focus orientation in the at least one upper focal plane 11099 of the at least one second upper-view measuring device 110. However, the at least one first mark 315 of the second reference element 310 is not necessarily in focus orientation of the at least one lower-view measuring device 120. For example, as Figure 3 and Figure 4As shown, the at least one downward-looking measuring device 120 can be focused on a first focal plane 12089, which is different from the at least one upward-looking focal plane 11099. Therefore, in a first alignment state, the at least one second downward-looking measuring device 120 is operated to focus on the at least one first mark 315 of the second reference element 310, thereby arranging the at least one first mark 315 of the second reference element 310 in a direction oriented within the second focal plane 12099 of the at least one downward-looking measuring device 120. The second focal plane 12099 is substantially coplanar with the upward focal plane 11099 of the second upward-looking measuring device 110. Once the at least one second downward-looking measuring device 120 has been focused on the at least one first mark 315 of the second reference element 310, this focus determines or sets the first focus state of the at least one second downward-looking measuring device 120. The at least one first mark 315 of the second reference element 310 is oriented within the second focal plane 12099 of the at least one downward-looking measuring device 120 in the first focus state. The focusing principle of the at least one second downward-looking measuring device 120 can be established in various ways, such as by focusing the imaging lens of the at least one second downward-looking measuring device 120 and / or by a displacement module, thereby ensuring that the at least one first mark 315 is oriented in the second downward-looking focal plane 12099.

[0086] Next, based on the fact that since the at least one first mark 315 is positioned in the upper focal plane 11099 and the second lower focal plane 12099 is substantially coplanar with the upper focal plane 11099, the at least one upper measuring device 110 is also focused on the at least one first mark 315. The improved alignment system 100 is able to align the second lower focal plane 12099 of the at least one second lower measuring device 120 with the upper focal plane 11099 of the at least one second upper measuring device 110, at least based on the first focusing state of the at least one second lower measuring device 120.

[0087] In particular, the improved alignment system 100 is configured to align the second lower-view focal plane 12099 of the at least one second lower-view measuring device 120 with the upper-view focal plane 11099 of the at least one second upper-view measuring device 110, based on a first focusing state and with the aid of one or more parameters selected from the optical characteristics of the second reference element 310. These optical characteristics may be based on the material and / or refractive index of the second reference element 310, the thickness 3199 of the second reference element, and the depth of focus of the at least one second lower-view measuring device 120.

[0088] While the alignment principle described above provides an improvement over known alignment techniques, further improvements can be obtained when considering the thickness 3199 of the second reference element 310. Although the at least one first mark 315 is at the same Z height, they may not be on the same focal plane of the two second measuring devices 110, 120 due to the focal offset effect of the second reference element 310. This is in Figure 3 As shown, the first focal plane 12089 of the at least one second downward-looking measuring device 120 is initially not in the same XY plane as the focal plane 11099 of the at least one second upward-looking measuring device 110.

[0089] More specifically, Figure 7 A schematic side view depicting a further improvement to the alignment principle according to this disclosure is provided, the side view being located in an approximate XZ plane. The improved alignment system 100 optionally further includes at least one second mark 3005 oriented within the at least one upper focal plane 11099 of the at least one second upper-view measuring device 100. More precise improved alignment is achieved because, in the first alignment state, i.e., when the second reference element 310 is positioned in both the upper field of view 11020 and the lower field of view 12020, the at least one second lower-view measuring device 120 is configured to also focus on the at least one second mark 3005. Figure 8 It shows in Figure 7 The schematic top view shows the respective fields of view of the at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120 during the alignment step illustrated. The schematic top view is depicted as being located in an approximate XY plane.

[0090] Subsequently, in a second alignment state (described below), the improved alignment system positions the second reference element 310 outside the downward field of view 12020 of the at least one second downward-looking measuring device 120. The at least one second downward-looking measuring device 120 then refocuses on the at least one second mark 3005, which determines the second focus state. A further improved alignment of the improved alignment system 100 according to this disclosure improves the alignment of the at least one downward-looking focal plane 12099 of the at least one second downward-looking measuring device 120 with the upward-looking focal plane 11099 of the at least one second upward-looking measuring device 110 based on the first and second focus states. Using this improved alignment, optical distortion caused by the thickness 3199 of the second reference element 310 can be highly corrected, and the downward-looking focal plane 12099 practically coincides with the upward-looking focal plane 11099. For example, in Figure 15 , 16 , Figure 17 , 18 as well as Figure 21 ,22 The second alignment state is shown, in which the second reference element 310 is removed from the fields of view 11020 and 12020, and the lower focal plane is no longer at the first focal plane 12089 but is at the second focal plane 11099, which is highly coincident with the upper focal plane 11099.

[0091] exist Figure 5 , 6 , Figure 7 , 8 , Figure 9 , 10 and Figure 11 , 12 An alternative example is shown, in which the improved alignment system 100 includes a support frame 300 configured to be mounted in a fixed position relative to the at least one second upward-looking measuring device 110. The support frame 300 supports the second reference element 310 in a first alignment state.

[0092] and Figure 7 , 8 The opposite example involves mounting at least one second mark 3005 at different locations within the upper focal plane 11099 in the improved alignment system 100. Figure 9 , 10 An example of this disclosure is shown, wherein at least one second mark 3005 is mounted to a support frame 300. The support frame 300 may be made as a separate component for supporting the second reference element 310, and / or in another example as shown in the mentioned figures, the support frame 300 may consist of various support frame components 301, which are similarly mounted in a fixed position relative to the at least one second downward-looking measuring device 120 of the improved alignment system 100.

[0093] Regarding the alignment principle, it should be noted that the improved alignment system 100 is configured to transform the first focus position of the at least one second mark 3005 acquired by the at least one second downward-looking measuring device 120 in the first alignment state to the second focus position of the at least one second mark 3005 acquired by the at least one second downward-looking measuring device 120 in the second alignment state. This transformation T maps the position of the at least one second mark 3005 defined in the first alignment state to the position of the at least one second mark 3005 defined in the second alignment state.

[0094] Preferably, the transformation T may include a rigid body transformation, having translations in the X and Y directions of the XYZ coordinate system and degrees of freedom in the rotZ orientation. Other transformations may be implemented, such as shearing, rotation, tilting, etc. By using high-quality telecentric optics, slight tilt variations (rotX, rotY) of the at least one second downward-looking measuring device 120 due to imperfections in the Z-axis can be at least partially compensated, but more complex mappings T may also be calculated that take into account higher-order distortions with more degrees of freedom (e.g., additional degrees of freedom, such as scaling in the X direction (scaleX) and / or scaling in the Y direction (scaleY), or the use of higher-order Zernike polynomials).

[0095] According to the improved alignment system 100 of this disclosure, various transformation techniques can be implemented, such as by translation (preferably in a plane perpendicular to the common longitudinal axis of the at least one second downward measuring device 120 and the at least one second upward measuring device 110) and / or by rotation about the common longitudinal axis, to transform the first focus position of the at least one first mark 315 to the second focus position of the at least one first mark 315 (or vice versa).

[0096] The same transformation T (associated with the mapping from the position of the at least one second mark 3005 defined in the first alignment state to the position of the at least one second mark 3005 defined in the second alignment state) is now applied to the position of the at least one first mark 315 defined in the first lower view focal plane 12089 by the at least one second lower view measuring device 120 in the first alignment state, and this provides the improved alignment system 100 with field calibration data for the at least one second lower view measuring device 120, which is now in the desired Z position (or in the desired second focal plane 12099).

[0097] At this stage, the two focal planes 11099 and 12099 are aligned, and the fields of view 11020 and 12020 of the two second measuring devices 110 and 120 substantially overlap. By calculating the transformation S between the two fields of view 11020 and 12020, the control unit 711 of the improved alignment system 100 can be configured to use S to computationally map the image (or position / or orientation in the image) of the at least one second upward measuring device 110 to the field of view 12020 of the at least one second downward measuring device 120, and vice versa.

[0098] This means that the two second measuring devices 110 and 120 are now aligned with high precision within their overlapping focal planes 11099 and 12099.

[0099] Furthermore, if the position of at least one first mark 315 on the second reference element 310 is known very precisely (either by external measurement or by an extremely precise manufacturing process), the at least one first mark 315 can be used to calibrate the fields of view 11020 and 12020 of the at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120 to a shared Cartesian XYZ coordinate system, thereby correcting optical aberrations of the optical system with high precision. For some applications, such as in Figure 1 In the device 10 depicted, the semiconductor die mark 2132 and the substrate mark 2012 can highly overlap at the bonding location, so this additional calibration may not be necessary.

[0100] To correct for changes in the calibrated relationship (X, Y, rotZ) between the measurement systems of the two second measuring devices 110 and 120 due to thermal drift (also known as calibration aging), the improved alignment system 100 includes at least one third mark 3025 (see Figure 13 , 14 and Figure 15 , 16 ), wherein, when viewed along a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device 120 and the at least one second upward-looking measuring device 110, the at least one third mark 3025 is located on the first side of the upward-looking focal plane 11099 of the second upward-looking measuring device 110 and at a certain distance from the upward-looking focal plane. Note that in Figure 13 , 14 and Figure 15 , 16 In the above view, the at least one third mark 3025 is located on the side of the upward focal plane 11099 that is closest to the at least one second upward measuring device 110 and therefore furthest from the at least one second downward measuring device 120 (indicated as the first side).

[0101] In addition to the at least one third mark 3025, the improved alignment system 100 can also implement improved correction for calibration aging because it can include at least one fourth mark 3026. When viewed along a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device 120 and the at least one second upward-looking measuring device 110, the at least one fourth mark 3026 is also located on the opposite second side of the upward-looking focal plane 11099 of the second upward-looking measuring device 110 and at a certain distance from the upward-looking focal plane. Note that in Figure 13 , 14 and Figure 15 , 16In the above view focal plane 11099, the at least one fourth mark 3026 is located on the side of the at least one second lower view measuring device 120 that is closest to and therefore furthest from the at least one second upper view measuring device 110 (indicated as the second side).

[0102] The additional at least one third mark 3025 and at least one fourth mark 3026 may optionally be included in one or more frame components. For example, the at least one third mark 3025 and the at least one fourth mark 3026 may be mounted to separate or identical frame components 3021, 3022, 3023 of the support frame 300, wherein one or more frame components 3021, 3022, 3023 do not include or incorporate any of the at least one first mark 315 and the at least one second mark 3005.

[0103] Advantages, such as Figure 13 , 14As shown in 15, 16, 19, 20, 21, and 22, the at least one third mark 3025 and the at least one fourth mark 3026 are included in the same frame components 3021, 3022, and 3023. The at least one third mark 3025 and the at least one fourth mark 3026 are arranged to define one or more orientations and / or positions of one or more first upward-looking measuring devices 110 relative to one or more downward-looking measuring devices 120. Frame components 3021, 3022, and 3023 include an optical mark carrier having a first carrier surface and a second carrier surface, wherein the second carrier surface is opposite to the first carrier surface. The at least one third mark 3025 is disposed on or near the first carrier surface, and the at least one fourth mark 3026 is disposed on or near the second carrier surface. The at least one third mark 3025 is arranged to allow the one or more downward-looking cameras 120 to create one or more first images through the optical mark carrier if the one or more downward-looking cameras 120 are facing the second carrier surface. The at least one fourth mark 3026 is arranged to allow the one or more upward-looking cameras 110 to create one or more second images via an optical mark carrier if the one or more upward-looking cameras 110 are facing the first carrier surface. The one or more first images are arranged to provide a first orientation and / or position of the one or more downward-looking cameras 120 relative to the at least one third mark 3025. The one or more second images are arranged to provide a second orientation and / or position of the one or more upward-looking cameras relative to the at least one fourth mark 3026. Optionally, the first orientation, first position, second orientation, second position, or any combination thereof may be used to determine one or more alignment imaging parameters or calibration parameters for the one or more downward-looking cameras 120 and the one or more upward-looking cameras 110.

[0104] The optical marking carrier may be further advantageous if it has an average refractive index (n) of approximately 2, or in the range of 1.0 to 3.0; or 1.5 to 2.5; or 1.7 to 2.3; or 1.75 to 2.25; or 1.8 to 2.2; or 1.85 to 2.15; or 1.9 to 2.1; or 1.95 to 2.05.

[0105] Optionally, the calibration of the at least one second downward-looking measuring device 120 can be further enhanced by using at least one fifth mark 3035, wherein the at least one fifth mark 3035 is oriented in the at least one upward-looking focal plane 11099 and is optionally mounted to further frame components 3031, 3032, 3033 of the support frame 300, such as... Figure 11 , 12 As shown.

[0106] In a preferred example, the frame components, particularly frame components 3021, 3022, and 3023, are made of a material having a refractive index n in the range of 1.9 to 2.1, particularly 1.95 to 2.05, more particularly 1.975 to 2.025, even more particularly 1.99 to 2.01, and even more particularly 1.995 to 2.005.

[0107] If the at least one second upward-looking measuring device 110 is configured to further determine the initial positions of the at least one fourth mark 3026 and / or the at least one fifth mark 3035 in a first alignment state, and to determine the subsequent positions of the at least one fourth mark 3026 and / or the at least one fifth mark 3035 in a second alignment state, the aforementioned calibration aging effect can be highly corrected. Next, the realignment step of the improved alignment system 100 includes realigning the at least one downward-looking focal plane 12099 of the at least one second downward-looking measuring device 120 with the at least one upward-looking focal plane 11099 of the at least one second upward-looking measuring device 110 based on one or more initial positions and one or more subsequent positions thus determined.

[0108] The positions of the at least one third mark 3025, the at least one fourth mark 3026, and / or the at least one fifth mark 3035 can be checked by any one of the at least one second upward-looking measuring device 110 and the at least one second downward-looking measuring device 120, and compared with their predetermined positions during the initial alignment or calibration. As long as these measurement positions do not change beyond the specifications for the at least one second upward-looking measuring device 110 and / or the at least one second downward-looking measuring device 120 relative to the positions determined during the initial alignment or calibration step, the calibration is considered correct and unaffected.

[0109] Because measurements on various third, fourth, and / or fifth marks, as well as top-view adjustment measurements on semiconductor dies 211, 212, and 213, can be performed very simultaneously before the semiconductor dies 211, 212, and 213 are positioned and bonded to the substrate 21 (see, for example...), Figure 1 Therefore, this method does not require additional platform movement or image acquisition.

[0110] When the predetermined calibration positions of at least one third mark 3025, at least one fourth mark 3026, and at least one fifth mark 3035 begin to change due to thermal drift, vibration, etc., the control unit 711 of the improved alignment system 100 will observe calibration aging. In this case, the control unit 711 has several options, such as rerunning and refreshing the calibration of the positions of the at least one third mark 3025, at least one fourth mark 3026, and at least one fifth mark 3035. However, this option takes time. Alternatively, adjustments to the XY and rotZ drift of various marks can be performed, and the calibration can be easily corrected by the control unit through calculation. In addition, higher-order effects can be detected by comparing the distances of the marks at the edge of the field of view, which is the most sensitive area of ​​the improved alignment system 100. This can be used for computational backmapping in a multi-degree-of-freedom (scaling, etc.) or higher-order transformation manner, or to trigger a new calibration aging process.

[0111] To ensure a precise alignment process, it is evident that the mutual orientation of the various components in the optical system remains undisturbed between the steps of the alignment process. Therefore, the improved alignment system 100 may include attachment features that attach a second reference element 310 to a position relative to the at least one second upward-looking measuring device 110 in a first alignment state. These attachment features can use magnetic force to attach the second reference element 310 to the position relative to the at least one second upward-looking measuring device 110. Therefore, the second reference element 310 may be provided with magnetic contacts that interact magnetically with corresponding magnetic contacts provided on the at least one second upward-looking measuring device 110 or the support structure 300 and / or the support frame member 301.

[0112] In an alternative example (which similarly ensures the undisturbed mutual orientation of the various components in the optical system), attachment features are provided for attaching the second reference element 310 to a position relative to the at least one second upward-looking measuring device 110 using a vacuum in a first alignment state. For example, a vacuum pump device may be provided that generates negative pressure or vacuum at the location where the second reference element 310 rests on the support structure 300 and / or support frame member 301 (e.g., via an air duct or air inlet opening).

[0113] In another example, the attachment feature is configured to attach the second reference element 310 to the support frame 300 in a mechanically shaped fit relative to the at least one second upward-looking measuring device 110 in a first alignment state. For example, the attachment feature may consist of at least one pair of cooperating first and second interlocking elements, the first interlocking element forming an integral part with the support frame 300 and / or the support frame component 301, and the second interlocking element forming an integral part with the second reference element 310.

[0114] In particular, the cooperating first and second interlocking elements can be configured as at least one recess and at least one protrusion, wherein the at least one recess and the at least one protrusion exhibit a circular, elliptical, or annular configuration. For example, at least a portion of the outer dimension of the at least one protrusion is larger than a corresponding portion of the inner dimension of the cooperating recess.

[0115] Various first, second, third, fourth, and fifth markers can be provided in the form of flat linear or dotted reference markers as shown in the figure. Alternatively, these reference markers can be formed as small spheres.

[0116] This disclosure also relates to a computer-implemented method for aligning at least one second downward-looking measuring device 120 and at least one second upward-looking measuring device 110 relative to each other. The computer-implemented alignment method can be executed by a control unit 711 and may include at least the following steps:

[0117] i) Orient at least one second upward measuring device 110 having an upward focal plane 11099 and an upward field of view 11020, the upward field of view pointing toward at least one second downward measuring device 120;

[0118] ii) Point the at least one second downward-looking measuring device 120 toward the at least one second upward-looking measuring device 110, the second downward-looking measuring device having at least one downward-looking focal plane 12099, 12089 and a downward-looking field of view 12020;

[0119] iii) In the first alignment state, a second reference element 310 is installed in the upper field of view 11020 of the at least one second upper field of view measuring device 110 and the lower field of view 12020 of the at least one second lower field of view measuring device 120, wherein the second reference element includes at least one first mark 315.

[0120] iv-1) Orient the at least one first mark 315 in the upper focal plane 11099;

[0121] v) In the first focusing state, the at least one second downward-looking measuring device 120 is focused on the at least one first mark 315;

[0122] vi) Based on the first focusing state, align the lower focal plane 12099 of the at least one second lower-view measuring device 120 with the upper focal plane 11099 of the at least one second upper-view measuring device 110.

[0123] Additionally, the method may include the following improvements, wherein the alignment step vi) is based on a first focus state and one or more parameters selected from the optical properties of the second reference element 310 (such as material, refractive index), the thickness of the second reference element 310, and the depth of focus of the at least one second downward-looking measuring device 120.

[0124] A further improved alignment process according to the method of this disclosure has the following steps:

[0125] iv-2) Orient at least one second mark 3005 in at least one upper focal plane 11099;

[0126] iv-3) Focus the at least one second downward-looking measuring device 120 onto the at least one second mark 3005;

[0127] vii) In the second alignment state, the second reference element 310 is moved out of the upper field of view 11020 and the lower field of view 12020, and

[0128] viii) The at least one second downward-looking measuring device 120 is focused on the at least one second mark 3005 in the second focusing state, and

[0129] vi-2) Based on the first focusing state and the second focusing state, align the second focal plane 12099 of the at least one second downward-looking measuring device 120 with the upward-looking focal plane 11099 of the at least one second upward-looking measuring device 110.

[0130] Preferably, alignment step vi-2) may include the following steps:

[0131] (ix) The first focus position of the at least one first mark 315 obtained by the at least one second downward-looking measuring device 120 in the first focus state is transformed into the second focus position of the at least one first mark 315 obtained by the at least one second downward-looking measuring device 120 in the second focus state.

[0132] The computer-implemented method according to this disclosure is designed to perform the transformation step ix by translating the first focal position to the second focal position in a plane perpendicular to the common longitudinal axis of the at least one second lower-view measuring device 120 and the at least one second upper-view measuring device 110 and by rotating about the common longitudinal axis.

[0133] This disclosure also relates to a computer program or product that includes instructions that, when executed by a computer, such as by a control unit 711, cause the computer and / or control unit 711 to perform one or more steps of a computer-implemented method according to this disclosure.

[0134] This disclosure also relates to a computer-readable storage medium including instructions that, when executed by a computer and / or control unit 711, cause the computer and / or control unit 711 to perform one or more steps of a computer-implemented method according to this disclosure.

[0135] Preferred embodiments of the improved alignment system 100 and / or improved alignment method have two main objectives:

[0136] Step 1): Perform at least one calibration and / or alignment on the at least one second downward-facing measuring device 120 and the at least one second upward-facing measuring device 110 that are facing each other;

[0137] Step 2): Perform at least one measurement to determine if the calibration and / or alignment is still valid.

[0138] Step 1) In, for example Figure 3 and Figure 5 As shown, the reference element 130 has at least one first mark 315 on its bottom side, for example, using a chromium layer on glass. At least one upward-looking device 110 is arranged to view the bottom side of the reference element 130, where the at least one first mark 315 is located at a focal plane 11099. This focal plane 11099 is the plane where critical imaging occurs, thus providing high precision. At least one downward-looking device 120 is arranged to view the top side of the reference element 130 as shown. The at least one downward-looking device 120 is arranged to also focus on the at least one first mark 315, but must image and / or sense through the thickness 3199 of the translucent reference element 130. This results in a focus shift due to refraction from the translucent material, which must be taken into account—this is the first focusing state.

[0139] The upward-looking device 110 and the downward-looking device 120 image and / or sense the at least one first mark 315 of the hand under substantially the same time and substantially the same environmental conditions (such as temperature, humidity, etc.). Then, using one or more positions of the at least one first mark 315, one or more fields of view (typically within the device) of the measuring devices 110, 120 are calibrated. Furthermore, based on at least two images of the at least one first mark 315 from the two measuring devices 110, 120, a mapping and / or transformation is calculated, which allows one or more positions in one field of view to be converted and / or transformed to another field of view, thereby aligning and / or calibrating the measuring system of the at least one upward-looking device 110 with the measuring system of the at least one downward-looking device.

[0140] Step 2) In, for example Figure 15 , Figure 16 , Figure 17 , Figure 18 , Figure 21 , Figure 22 and Figure 23 As shown in the diagram. After calibration and / or alignment, in step 1), the reference element 130 with the at least one first mark 315 is removed from the field of view of the at least one upward-looking measuring device 110. During the use of the device (such as in production), the effectiveness of the calibration and / or alignment can be determined without the need for frequent installation of the reference element 130. To detect whether the calibration and / or alignment is still effective, at least one other mark is required. These other marks are the at least one second mark 3005, the at least one third mark 3025, the at least one fourth mark 3026, and / or the at least one fifth mark 3035. At least two of these other marks face upward and can be sensed and / or imaged by at least one downward-looking measuring device 120. At least two of these other marks face downward and can be sensed and / or imaged by at least one upward-looking measuring device 110. After the removal of the reference element 130, the focusing distance of the at least one downward-looking device 120 shifts compared to the first focusing position. Therefore, a measuring device with a sufficiently high depth of focus is used as the at least one downward-looking measuring device 120 to sense and / or image other marks on the focal plane 11099. Additionally or alternatively, the at least one downward-looking measuring device 120 may be arranged to refocus on one or more other marks—this is a “second focus state.” Refocusing can be a movement of the downward-looking measuring device 120 and / or a change in focus and / or a change in the measuring device 120 between at least two focal planes.

[0141] During the calibration and / or alignment in step 1), at least one position of the at least one first marker 315 is sensed and / or imaged—this is considered the “initial position.” In step 2), at least one position of one or more other markers is imaged without reference element 130, without loss of production throughput—this is referred to as the “subsequent position.” The effectiveness of the alignment and / or calibration in step 1) can be determined in step 2 by comparing at least one “initial position” and at least one “subsequent position.”

[0142] The improved alignment system and method described herein can be advantageously further improved by using the "Optical reference device for determining the orientation and / or position of a camera" disclosed in German patent application DE 10 2023 133 895.1 filed on December 4, 2023, by the same applicant and filed concurrently with this application, which is incorporated herein by reference. The optical reference device is used to determine one or more orientations and / or positions of one or more first cameras arranged as one or more upward or downward cameras relative to one or more second cameras arranged as one or more downward or upward cameras. The optical reference device includes: a marker carrier having a first carrier surface and a second carrier surface, wherein the second carrier surface is opposite to the first carrier surface; at least one first reference being one or more first marks on or near the first carrier surface; and at least one second reference being one or more first marks on or near the second carrier surface; wherein the marker carrier includes one or more imaging portions; the at least one first reference is arranged such that if the one or more first cameras face the second carrier surface, the one or more first cameras can capture one or more first images through the one or more imaging portions; wherein the at least one second reference is arranged such that if the one or more second cameras face the first carrier surface, the one or more second cameras can capture one or more second images through the one or more imaging portions; wherein the one or more first images are arranged to provide a first orientation and / or position of the one or more first cameras relative to the at least one first reference; and wherein the one or more second images are arranged to provide a second orientation and / or position of the one or more second cameras relative to the at least one second reference.

[0143] If the average refractive index (n) of the imaging portion is approximately 2, or in the range of 1.0 to 3.0; or 1.5 to 2.5; or 1.7 to 2.3; or 1.75 to 2.25; or 1.8 to 2.2; or 1.85 to 2.15; or 1.9 to 2.1; or 1.95 to 2.05, then the optical tool reference can be more favorable.

[0144] During the alignment or calibration process described herein, and in order to eliminate at least one error in determining the first position, the alignment system may include a fixing feature configured to fix the reference element in a position relative to the at least one upward-looking measuring device in the first alignment state.

[0145] In one example, the fixing feature is configured to use magnetic force to fix the reference element in position relative to the at least one upward-looking measuring device in a first alignment state, while in another example, the fixing feature is configured to use vacuum to fix the reference element in position relative to the at least one upward-looking measuring device in a first alignment state.

[0146] Alternatively, in another example, the fixing feature is configured to fix the reference element relative to the at least one upward measuring device on the support frame in a first alignment state, and the fixing feature consists of at least one pair of cooperating first interlocking elements and second interlocking elements.

[0147] In the latter example, the pair of cooperating first and second interlocking elements can be configured as at least one recess and at least one protrusion, wherein the at least one recess and the at least one protrusion have a circular, elliptical, or annular configuration. Additionally, at least a portion of the outer dimension of the at least one protrusion can be excessively large compared to the inner dimension of the corresponding portion of the cooperating recess, thereby ensuring automatic centering of the reference element on the support frame.

[0148] List of reference numerals

[0149] 10 First Pick-up and Placement Device

[0150] 11 First upward-looking measuring device

[0151] 12 First downward-looking measuring device

[0152] 13 First key to close the head

[0153] 14 First Reference Element

[0154] 20 substrates

[0155] 100 Improved Alignment System

[0156] 110 Second Upward Measurement Device

[0157] 120 Second Downward Sight Measurement Device

[0158] 130 Second Key Connector

[0159] 211 Semiconductor Die

[0160] 212 Semiconductor Die

[0161] 213 Semiconductor Die

[0162] 300 support frame

[0163] 301 Support Frame Components

[0164] 310 Second Reference Element

[0165] 315 First Mark

[0166] 711 Improved Alignment System Control Unit

[0167] 740 Displacement Module for Second Downward-Looking Measurement Device

[0168] 1111 First upward-looking imaging ray of the first upward-looking measuring device

[0169] 1112 The second upward-looking imaging ray of the first upward-looking measuring device

[0170] 1120 Field of view of the first upward-looking measuring device

[0171] 1211 First downward-looking imaging ray of the first downward-looking measuring device

[0172] 1212 The second downward-looking imaging ray of the first downward-looking measuring device

[0173] 1220 First downward-looking measurement device field of view

[0174] 1311 First key joint marking

[0175] 1411 Marking of the first reference element

[0176] 2012 substrate marking

[0177] 2132 nude film marking

[0178] 3005 Second Mark

[0179] 3021 frame components

[0180] 3022 frame components

[0181] 3023 frame components

[0182] 3025 Third Mark

[0183] 3026 Fourth Mark

[0184] 3031 Additional Support Frame Components

[0185] 3032 Additional Support Frame Components

[0186] 3033 Additional Support Frame Components

[0187] 3035 Fifth Marker

[0188] 3101 First surface side of the second reference element

[0189] 3102 Second surface side of the second reference element

[0190] Thickness of the second reference element 3199

[0191] 7111 First control line for the second upward-looking measuring device

[0192] 7112 Second control line for the second downward-looking measuring device

[0193] 7401 is used for the control lines of the displacement module.

[0194] 11011 The first upward-looking imaging ray of the second upward-looking measuring device

[0195] 11012 Second upward-looking imaging ray of the second upward-looking measuring device

[0196] 11020 Second upward-looking measurement device's upward-looking field of view

[0197] 11099 Second upward-looking measuring device, upward-looking focal plane

[0198] 12011 Second Downward Sight Measurement Device First Downward Sight Imaging Ray

[0199] 12020 Second Downward Sight Measurement Device Field of View

[0200] 12089 Second Downward Sight Measurement Device First Focal Plane

[0201] The second focal plane of the 12099 second downward-looking measuring device

[0202] Marking of the second bonding head of 13013

[0203] 13075 bonding head viewport

Claims

1. An alignment system (100) for aligning at least one downward-looking measuring device (120) and at least one upward-looking measuring device (110) relative to each other, said alignment system (100) comprising at least: At least one upward-looking measuring device (110) has at least one upward-looking focal plane (11099) and an upward-looking field of view (11020) pointing toward at least one second downward-looking measuring device (120). The at least one downward-looking measuring device (120) has at least one downward-looking focal plane (12099) and a downward-looking field of view (12020) pointing toward the at least one upward-looking measuring device (110); and Reference element (310) includes at least one first mark (315); In the first alignment state The alignment system (100) is configured to position the reference element (310) within the upper focal plane (11099) and the lower focal plane (12099), such that the at least one first mark (315) is oriented within the at least one upper focal plane (11099), and The at least one downward-looking measuring device (120) is configured to focus on the at least one first mark (315) in a first focusing state; and wherein The alignment system (100) is configured to align at least one lower focal plane (12099) of the at least one lower-view measuring device (120) with the upper focal plane (11099) of the at least one upper-view measuring device (110) based at least on the first focusing state.

2. The alignment system (100) according to claim 1, wherein, The alignment system (100) is configured to align the at least one lower focal plane (12099) of the at least one lower focal plane (120) with the upper focal plane (11099) of the at least one upper focal plane (110) based on the first focusing state and one or more parameters selected from the optical characteristics of the reference element (310), the thickness (3199) of the reference element (310), and the depth of focus of the at least one lower focal plane (120).

3. The alignment system (100) according to claim 1 or 2, wherein, The alignment system (100) further includes at least one second mark (3005) oriented in the at least one upper focal plane (11099), and In the first alignment state, The at least one downward-looking measuring device (120) is configured to focus on the at least one second mark (3005), and In the second alignment state The alignment system (100) is configured to position the reference element (310) outside the lower field of view (12020), and The at least one downward-looking measuring device (120) is configured to focus on the at least one second mark (3005) in a second focusing state, and wherein The alignment system (100) is configured to align the at least one lower focal plane (12099) of the at least one lower-view measuring device (120) with the upper focal plane (11099) of the at least one upper-view measuring device (110) based on both the first focusing state and the second focusing state.

4. The alignment system (100) according to any one of claims 1 to 3, wherein, The alignment system (100) further includes a support frame (300) configured to be fixed in position relative to the at least one upward measuring device (110) and configured to support the reference element (310) in the first alignment state.

5. The alignment system (100) according to claim 4, wherein, The second mark (3005) is installed on the support frame (300).

6. The alignment system (100) according to any one or more of claims 3 to 5, wherein, For alignment purposes, the alignment system (100) is configured to change the first focus position of the at least one second mark (3005) acquired by the at least one downward-looking measuring device (120) in the first alignment state to the second focus position of the at least one second mark (3005) acquired by the at least one downward-looking measuring device (120) in the second alignment state.

7. The alignment system (100) according to claim 6, wherein, The alignment system (100) is configured to transform the first focus position of the at least one first mark (315) to the second focus position of the at least one first mark (315).

8. The alignment system (100) according to any one or more of the preceding claims, wherein, The alignment system (100) includes at least one third mark (3025) which is positioned at a distance from the upper focal plane (11099) and on a first side of the upper focal plane when viewed in a direction parallel to the common longitudinal axis of the at least one second lower view measuring device (120) and the at least one second upper view measuring device (110).

9. The alignment system (100) according to any one or more of the preceding claims, wherein, The alignment system (100) includes at least one fourth mark (3026) which is positioned at a distance from the upper focal plane (11099) and on the opposite side of the upper focal plane when viewed in a direction parallel to the common longitudinal axis of the at least one second lower-view measuring device (120) and the at least one second upper-view measuring device (110).

10. The alignment system (100) according to any one or more of the preceding claims, wherein, The alignment system (100) includes at least one fifth mark (3035) oriented in the at least one upper focal plane (11099).

11. The alignment system (100) according to claim 8, 9 or 10, further comprising at least one frame component (302, 3021, 3022, 3023) and / or an additional support frame component (3031, 3032, 3033), wherein the at least one frame component and / or the additional support frame component includes at least one third mark (3025) and / or at least one fourth mark (3026) and / or at least one fifth mark (3035).

12. The alignment system (100) according to claim 11, wherein, The at least one frame component (302, 3021, 3022, 3023) and / or the additional support frame component (3031, 3032, 3033) are made of a material with a refractive index n in the range of 1.9 to 2.1, particularly 1.95 to 2.05, more particularly 1.975 to 2.025, even more particularly 1.99 to 2.01 and even more particularly 1.995 to 2.

005.

13. The alignment system (100) according to any one or more of claims 8 to 12, wherein, The at least one upward-looking measuring device (110) is configured to additionally determine the initial position of the at least one fourth mark (3026) and / or the at least one fifth mark (3035) in the first alignment state, and to determine the subsequent position of the at least one fourth mark (3026) and / or the at least one fifth mark (3035) in the second alignment state; and The alignment system (100) is configured to realign the at least one lower focal plane (12099) of the at least one lower-view measuring device (120) with the at least one upper focal plane (11099) of the at least one upper-view measuring device (110) based on one or more initial positions and / or one or more subsequent positions thus determined.

14. The alignment system (100) according to any one or more of the preceding claims, wherein, The reference element (310) is coplanar.

15. The alignment system according to claim 14, wherein, The reference element (310) is highly transmissive to the at least one downward-looking measuring device (120).

16. The alignment system (100) according to any one or more of claims 3 to 15, wherein, In either the first alignment state or the second alignment state, the at least one downward-looking measuring device (120) is configured to focus in the first focusing state and / or the second focusing state by refocusing its at least one downward-looking focal plane (12099).

17. The alignment system (100) according to any one or more of claims 3 to 16 further includes a displacement module configured to move the at least one downward measuring device (120) from the first focusing state toward the second focusing state at least along a direction substantially parallel to the common longitudinal axis of the at least one second downward measuring device (120) and the at least one second upward measuring device (110).

18. A computer-implemented method for aligning at least one downward-looking measuring device (120) and at least one upward-looking measuring device (110) relative to each other, the alignment method comprising at least the following steps: i) Orient at least one upward-looking measuring device (110) having an upward-looking focal plane (11099) and an upward-looking field of view (11020) toward at least one second downward-looking measuring device (120); ii) Orient at least one downward-looking measuring device (120) having at least one downward-looking focal plane (12099) and a downward-looking field of view (12020) toward the at least one upward-looking measuring device (110); iii) In the first alignment state, a reference element (310) containing at least one first mark (315) is mounted in the upper field of view and the lower field of view; as well as iv-1) Orient the at least one first mark (315) in the upper focal plane (11099); v) In the first focusing state, the at least one downward-looking measuring device (120) focuses on the at least one first mark (315). vi) Based on the first focusing state, align the lower focal plane (12099) of the at least one lower-view measuring device (120) with the upper focal plane (11099) of the at least one upper-view measuring device (110).

19. The computer-implemented method according to claim 18, wherein, The alignment step vi) is based on the first focusing state and one or more parameters selected from the optical characteristics of the reference element (310), the thickness (3199) of the reference element (310), and the depth of focus of the at least one downward-looking measuring device (120).

20. The computer-implemented method according to claim 18 or 19, further comprising the following steps: iv-2) Orient at least one second mark (3005) in the at least one upper focal plane (11099); iv-3) Focus the at least one downward-looking measuring device (120) on the at least one second mark (3005); vii) In the second alignment state, the reference element (310) is moved out of the upper and lower fields of view; and viii) In the second focusing state, the at least one downward-looking measuring device (120) focuses on the at least one second mark (3005); and vi-2) Based on the first focusing state and the second focusing state, align the second focal plane of the at least one downward-looking measuring device (120) with the upward-looking focal plane (11099) of the at least one upward-looking measuring device.

21. The computer-implemented method according to claim 20, wherein, The alignment step vi-2) includes the following steps: ix) transforms the first focus position of the at least one first mark (315) obtained by the at least one downward-looking measuring device (120) in the first focus state into the second focus position of the at least one first mark (315) obtained by the at least one downward-looking measuring device (120) in the second focus state.

22. The computer-implemented method according to claim 21, wherein, The transformation step (ix) includes: transforming the first focal position to the second focal position by translation in a plane perpendicular to the common longitudinal axis of the at least one second lower-view measuring device (120) and the at least one second upper-view measuring device (110) and / or by rotation about the common longitudinal axis.

23. The computer-implemented method according to any one of claims 19 to 22, wherein, The alignment system includes at least one third mark (3025) that, when viewed along a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device (120) and the at least one second upward-looking measuring device (110), is positioned at a distance from the upward-looking focal plane (11099) and on a first side of the upward-looking focal plane, and the method includes the following further steps: The initial position of the at least one third mark (3025) is determined using the at least one downward-looking measuring device (120) in the first focusing state, and the subsequent position of the at least one third mark (3025) is determined in the second focusing state; and Based on one or more initial positions and / or one or more subsequent positions thus determined, the lower focal plane (12099) of the at least one lower-view measuring device (120) is realigned with the upper focal plane (11099) of the at least one upper-view measuring device (110).

24. The computer-implemented method according to claim 23, wherein, The alignment system (100) further includes at least one fourth mark (3026) which, when viewed along a direction parallel to the common longitudinal axis of the at least one second downward-looking measuring device (120) and the at least one second upward-looking measuring device (110), is positioned at a distance from the upward-looking focal plane (11099) and on a second side opposite to the upward-looking focal plane, and the method includes the following further steps: The initial position of the at least one fourth mark (3026) is determined using the at least one upward-looking measuring device (110) in the first focusing state, and the subsequent position of the at least one fourth mark (3026) is determined in the second focusing state; and Based on one or more initial positions and / or one or more subsequent positions of the at least one third mark (3025) and / or the at least one fourth mark (3026) thus determined, the lower focal plane (12099) of the at least one lower-view measuring device (120) is realigned with the upper focal plane (11099) of the at least one upper-view measuring device (110).

25. The computer-implemented method according to any one of claims 20 to 24, wherein, The alignment system (100) includes at least one fifth mark (3035) oriented in the at least one upper focal plane (11099), and the method includes the following further steps: The initial position of the at least one fifth mark (3035) is determined using the at least one upward-looking measuring device (110) in the first focusing state, and the subsequent position of the at least one fifth mark (3035) is determined in the second focusing state; and Based on one or more initial positions and one or more subsequent positions of the at least one second mark (3005) and / or the at least one fifth mark (3035) thus determined, the lower focal plane (12099) of the at least one lower-view measuring device (120) is realigned with the upper focal plane (11099) of the at least one upper-view measuring device (110).

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