Active synchronous vibration damping of placement heads.

Abstract

The electronic device placement system includes a placement head including a spindle, a positioning system configured to move the spindle between a gripping position and a placement position, a spindle assembly Z-drive, and a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the positioning of the spindle, the piezoelectric stage including a motion controller and a spindle accelerometer system connected to the motion controller. The electronic device placement system includes a substrate support configured to hold a substrate that is a target for placement of an electronic component by the spindle, and a substrate accelerometer system mounted to the substrate support, the substrate accelerometer system configured to measure vibrations in the X and Y directions.

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 419,815, entitled "ACTIVE SYCHRONIZED VIBRATION DAMPING OF PLACEMENT HEAD," filed October 27, 2022, the disclosure of which is incorporated by reference.

[0002] The present invention relates generally to the placement of electronic devices, components, and / or dies on substrates such as wafers, printed circuit boards, fan-out panels, dies, etc. More particularly, the present invention relates to placement methods and systems with improved precision and accuracy in aligning features of placed devices to targets. [Background technology]

[0003] The state-of-the-art solution for ultra-high precision positioning is to create a heavy granite base for the equipment, which is mounted on special vibration dampers to eliminate vibrations from outside the equipment caused by foot traffic near the equipment. To prevent vibrations caused by fans, these equipment also do not have an integrated control system, but have a separate cabinet for this purpose. On top of this heavy base, the positioning system often consists of ceramic beams using air bearings to provide perfectly smooth movement and no vibrations.

[0004] These types of devices present a number of challenges.

[0005] The first challenge is cost: these devices are very expensive compared to steel frame devices, which typically include steel beams, linear ball bearings, and integrated control systems.

[0006] A second challenge is that these devices require the positioning system to move slowly and allow for a long settling time to ensure the placement nozzle comes to a complete stop, which is why these devices are typically lower powered than less accurate equipment.

[0007] A third problem is that these devices require separate control cabinets, which take up extra floor space and are expensive in the clean rooms required for this type of assembly process.

[0008] Therefore, a device, system, and / or method that improves the accuracy of electronic assembly equipment to sub-micron levels by eliminating vibration of the nozzle of a placement head relative to the substrate on which the nozzle places a device would be favorably received in the art. Summary of the Invention

[0009] According to one aspect, an electronic assembly system includes a placement head including a spindle, a positioning system configured to move the spindle between a gripping position and a placement position, a spindle assembly Z-drive, and a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the placement of the spindle, the piezoelectric stage including a motion controller and a spindle accelerometer system connected to the piezoelectric stage motion controller, the spindle accelerometer system configured to measure vibrations in the X and Y directions. The electronic assembly further includes a substrate support configured to hold a substrate that is a target for placement of an electronic component by the spindle, and a substrate accelerometer system mounted on the substrate support, the substrate accelerometer system configured to measure vibrations in the X and Y directions, the substrate accelerometer system connected to the piezoelectric stage motion controller.

[0010] According to another aspect, a placement head for an electronic assembly system includes a spindle, a positioning system configured to move the spindle between a gripping position and a placement position, a spindle assembly Z-drive, and a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the placement of the spindle, the piezoelectric stage including a motion controller and a spindle accelerometer system connected to the piezoelectric stage motion controller, the spindle accelerometer system configured to measure vibrations in the X and Y directions.

[0011] According to another aspect, a method for synchronizing a spindle head for vibration damping comprises providing an electronic assembly system including a placement head, the placement head including a spindle, a positioning system configured to move the spindle between a gripping position and a placement position, a spindle assembly Z-drive, and a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the placement of the spindle, the piezoelectric stage including a motion controller and a spindle accelerometer system connected to the piezoelectric stage motion controller, the spindle accelerometer system configured to measure vibrations in the X and Y directions. The electronic assembly system further includes a substrate support configured to hold a substrate targeted for placement of an electronic component by the spindle, and a substrate accelerometer system mounted on the substrate support, the substrate accelerometer system configured to measure vibrations in the X and Y directions, the substrate accelerometer system connected to the piezoelectric stage motion controller. The method includes receiving, by a piezoelectric stage motion controller, signals from a spindle accelerometer system and receiving, by the piezoelectric stage motion controller, signals from a substrate accelerometer system. The method includes processing, by the piezoelectric stage motion controller, signals from each of the spindle accelerometer system and the substrate accelerometer system. The method includes synchronizing, by the piezoelectric stage motion controller, relative vibrational motion between the placement head and a substrate mounted on a substrate support caused by at least one vibration. [Brief explanation of the drawings]

[0012] The above, and further advantages of the present invention may be better understood by reference to the following description taken in conjunction with the accompanying drawings, in which reference numerals indicate like elements and shapes in the various views. For purposes of clarity, not every element may be labeled in every view. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. [Figure 1] 1 illustrates a top view of an electronic device positioning system according to one embodiment. [Figure 2] 2 illustrates a side view of the electronic device positioning system of FIG. 1 according to one embodiment. [Figure 3A] 1 illustrates a schematic side view of an electronic device positioning system including a downward-looking camera and a spindle with a nozzle for gripping an electronic device out of the downward-looking camera's visual path, according to one embodiment. [Figure 3B] 6B illustrates a schematic side view of the electronic device placement system of FIG. 6A including a downward-facing camera and a nozzle for gripping an electronic device above a substrate, according to one embodiment. [Figure 4] 10 shows a graphical representation of acceleration patterns over time caused by vibrations in the X and Y directions and measured by both the spindle and substrate support accelerometer systems before synchronous motion decay, according to one embodiment. [Figure 5] 10 shows a graphical representation of acceleration patterns over time after synchronous motion decay caused by vibrations in the X and Y directions and measured by both the spindle and substrate support accelerometer systems, according to one embodiment. [Figure 6] 1 illustrates a method for positioning an electronic device, according to one embodiment. Detailed Description

[0013] References in the specification to "one embodiment" or "an embodiment" mean that the particular feature, structure, or feature described in connection with the embodiment is included in at least one embodiment of the inventive subject matter. References in the specification to a particular embodiment need not all refer to the same embodiment.

[0014] The present invention will now be described in more detail with reference to exemplary embodiments thereof, as illustrated in the accompanying drawings. While the present invention will be described in conjunction with various embodiments and examples, it is not intended that the invention be limited to such embodiments. On the contrary, the present invention encompasses various alternatives, modifications, and equivalents as will be appreciated by those skilled in the art. Those of ordinary skill in the art will recognize additional implementations, modifications, and embodiments, as well as other fields of use within the scope of the present disclosure described herein.

[0015] The present disclosure enables placement of electronic devices, such as dies or similar components, on substrates or printed circuit boards with better alignment of the device's features to targets on the substrate than prior art equipment. For example, the inventive electronic device placement systems and methods described herein are capable of placing electronic devices with an accuracy of 1 micron or better.

[0016] Furthermore, the embodiments described in this disclosure allow for the manufacture of low-cost devices using steel positioning systems and standard linear ball bearings that achieve accuracy comparable to or better than granite block devices with ceramic beams on air bearings. This allows for much higher speeds because even some of the settling time that makes state-of-the-art high-precision devices so slow can be eliminated. This may also reduce costs in the manufacture of the device by eliminating the need for separate control cabinets and damped floor materials, or by diverting any traffic within the device away from state-of-the-art devices.

[0017] In one embodiment, Figure 1 illustrates a top view of an electronic device positioning system 10, while Figure 2 illustrates a side view of the electronic device positioning system 10 of Figure 1. As shown in Figures 1 and 2, the electronic device positioning system 10 includes a positioning system including a pair of parallel linear bearings 12a and 12b disposed and extending in the Y direction on Y axes 13a and 13b, respectively. The positioning system further includes three beams, namely, a first beam 14a, a second beam 14b, and a third beam 14c, extending between the pair of linear bearings 12a and 12b.

[0018] The first beam 14a is movably coupled to the linear bearings 12a and 12b and is disposed along a first X-axis 15a perpendicular to the Y-axis 13a and 13b. Similarly, the second beam 14b is movably coupled to the linear bearings 12a and 12b and is disposed along a second X-axis 15b perpendicular to the Y-axis 13a and 13b. Similarly, the third beam 14c is movably coupled to the linear bearings 12a and 12b and is disposed along a third X-axis 15c perpendicular to the Y-axis 13a and 13b. Therefore, the first, second, and third beams 14a, 14b, and 14c are parallel beams and are disposed along the Y-axis 13a and 13b, spaced apart from each other, between the pair of parallel linear bearings 12a and 12b. In particular, the third beam 14c is located between the first beam 14a and the second beam 14b. In other words, the first beam 14a is located on a first side of the electronic device positioning system 10, while the second beam 14b is located on a second side of the electronic device positioning system 10, with the third beam 14c located therebetween. The first, second, and third beams 14a, 14b, and 14c are configured to move independently in the Y direction along the Y axes 13a and 13b relative to the linear bearings 12a and 12b, respectively.

[0019] As shown, the positioning system includes a first carriage 16a movably coupled to a first beam 14a. The first carriage 16a is configured to move relative to the first beam along a first X-axis 15a. Similarly, the positioning system further includes a second carriage 16b movably coupled to a second beam 14b. The second carriage 16a is configured to move relative to the second beam 14b along a second X-axis 15b. Similarly, the positioning system includes a first carriage 16c movably coupled to a third beam 14c. The third carriage 16c is configured to move relative to the third beam 14c along the first X-axis 15c.

[0020] The parallel linear bearings 12a, 12b, and / or the aforementioned beams 14a, 14b, 14c, and / or carriages 16a, 16b, 16c may include any type of arrangement or bearing system configured to allow movement in both the X and Y directions along the X and Y axes of the spindle assembly and / or downward looking camera system. The connections between these bearings, beams, and carriages may take any form, such as wheels / rollers, sliding movements, or any other type of controllable precision bearing system.

[0021] The first spindle 18a of the first placement head 25a is movably coupled to the first carriage 16a. In particular, the first spindle 18a is attached to or otherwise coupled to a first piezo stage 20a, which is attached to or coupled to a first spindle assembly Z drive 22a. In particular, the first spindle assembly Z drive 22a is movably coupled to the first carriage 16a and configured to move relative to the first carriage 16a along a first Z axis 24a. The first spindle assembly Z drive 22a is configured to move the first spindle 18a along the first Z axis 24a. The first piezo stage 20a is movably coupled between the first spindle assembly Z drive 22a and the first spindle 20a. The first piezo stage 20a is configured to move the first spindle 18a relative to the first spindle assembly Z drive 22a to make fine adjustments to the placement of the first spindle 18a.

[0022] Like the first spindle 18a, the second spindle 18b of the second placement head 25b is movably coupled to the second carriage 16b. In particular, the second spindle 18b is attached to or otherwise coupled to a second piezo stage 20b, which is attached to or coupled to a second spindle assembly Z-drive 22b. In particular, the second spindle assembly Z-drive 22b is movably coupled to the second carriage 16b and configured to move relative to the second carriage 16b along a second Z-axis 24b. The second spindle assembly Z-drive 22b is configured to move the second spindle 18b along the second Z-axis 24b. The second piezo stage 20b is movably coupled between the second spindle assembly Z-drive 22b and the second spindle 20b. The second piezo stage 20b is configured to move the second spindle 18b relative to the second spindle assembly Z-drive 22b to make fine adjustments to the placement of the second spindle 18b.

[0023] The first and second spindles 18a, 18b may be spindle assemblies including a transparent first spindle body 19a and a transparent second spindle body 19b, respectively. The transparent first and second spindle bodies 19a, 19b may include a pair of glass plates 26a, 26b, one above and one below the spindle 18a, 18b structure. If light of different wavelengths, such as infrared or X-rays, is used for illumination, other transparent materials may be used instead of glass plates. Furthermore, the main structure of the spindles 18a, 18b may be made of a transparent material. The first and second spindles 18a, 18b may include vertically aligned nozzles 28a, 28b, respectively. In some embodiments, the spindle nozzles 28a, 28b may also be made of a transparent material. Furthermore, the first and second spindles 18a, 18b may each be configured to provide an air supply to the spindle nozzles 28a, 28b, respectively, to generate vacuum suction and / or air exhaust from the nozzles 28a, 28b. The spindles 18a, 18b may further include theta drives 30a, 30b, respectively, to rotate the glass sheet to allow for gripping and positioning at different angles.

[0024] As shown, nozzles 28a, 28b each grasp a respective electronic device 32a, 32b, such as a die or similar component. The combination of linear bearings 12a, 12b, beams 14a, 14b, Z drives 22a, 22b, and θ drives 30a, 30b in a positioning system enables electronic device positioning system 10 to grasp and move electronic devices 32a, 32b in the X, Y, Z, and θ (rotational) axes over long distances. For the first and second spindles 18a, 18b, once the gripped electronic devices 32, 32b are mounted or otherwise positioned on the nozzles 28a, 28b, the electronic devices 32a, 32b may be transported from a gripping location, such as a supply area and / or supply bank (not shown), to a device imaging location and / or placement location over a substrate 34 or other target, as described below.

[0025] In the illustrated embodiment, the electronic device positioning system 10 further includes a first upward-facing camera 36 configured to image the bottom surface of an electronic device. In particular, the first upward-facing camera 36 may be configured to image an electronic device, such as the first electronic device 32a, held by the first spindle 18a. The image capture by the first upward-facing camera 36 occurs prior to the positioning operation of the first spindle 18a to position the first electronic device 32a.

[0026] Similar to the first upward-facing camera 36, ​​the electronic device positioning system 10 further includes a second upward-facing camera 38 configured to image the bottom surface of an electronic device. In particular, the second upward-facing camera 38 may be configured to image an electronic device, such as the second electronic device 32b, held by the second spindle 18b. The imaging by the second upward-facing camera 38 occurs prior to the positioning operation of the second spindle 18b to position the second electronic device 32b.

[0027] The electronic device placement system 10 further includes an equipment base 40 located below the positioning system, linear bearings 12a, 12b, beams 14a, 14b, 14c, and the like. The positioning system may be operably attached to or connected to the equipment base 40 of the electronic device placement system 10. The equipment base 40 includes a substrate support 41 having a substrate holding system 42 for holding a substrate 34 upon which the first and second electronic devices 32a, 32b can be placed during placement operations of the respective first and second spindles 18a, 18b. A first upward-facing camera 36, ​​facing upward, is located on a first side of the substrate holding system 42, and a second upward-facing camera 38, facing downward, is located on a second side of the substrate holder 42. In other words, a first side of the substrate holder 42 is adjacent to the first ends of the linear bearings 12a, 12b, and a second side of the substrate holder 42 is adjacent to the second (opposite) ends of the linear bearings 12a, 12b.

[0028] The electronic device placement system 10 further includes a downward-looking camera 50 coupled to the third carriage 16c. While the embodiment shown in FIGS. 1 and 2 includes a single downward-looking camera 50, it should be understood that embodiments in which more than one downward-looking camera is disposed are contemplated. For example, the downward-looking cameras may be disposed on separate placement heads and / or spindle assemblies. As shown in FIGS. 1 and 2, the downward-looking camera 50 is movable over the first spindle 18a during placement of a first electronic device, such as the first electronic device 32a, by the first spindle 18a. The downward-looking camera 50 may be positionable to roughly locate over targets (e.g., within 100 microns) on the X-, Y-, Z-, and rotational axes at which the main axes X, Y, Z, and θ of the positioning system of the beams 14a, 14b, and 14c, carriages 16a, 16b, and 16c, and Z drives 22a, 22b, and 52, fully stop.

[0029] Once positioned, the downward-facing camera 50 is configured to image the outer edge of a gripped electronic device during placement of the first spindle 18a via the transparent first spindle body (described above). Similarly, the downward-facing camera 50 can move over the second spindle 18b during placement of a second electronic device, such as the second device 32b, by the second spindle 18b. To do this, the first beam 14a can be moved along the linear bearings 12a, 12b away from the substrate 34 and toward the upward-facing camera 36 and / or the supply bank or gripping position. The second beam 14b can then be moved above or above the substrate 34, whereby the downward-facing camera 50 can be configured to image the outer edge of a gripped electronic device during placement of the second spindle 18b via the transparent second spindle body (described above). The downward-looking camera 50 is also movable or configured to be moved in the vertical Z direction via a camera Z drive 52 which allows the downward-looking camera 50 to focus on the device as well as the substrate 34 when suspended above the substrate 34.

[0030] Thus, the first and second beams 14a, 14b (i.e., alignment beams) of the system 10 may support the spindles 18a, 18b, respectively, and move each spindle 18a, 18b independently of the third beam 14c (i.e., camera beam) in the X, Y, and Z axes, as long as the first and second beams 14a, 14b remain on their respective sides of the third beam 14c. In other words, the first, second, and third beams 14a, 14b, 14c may not be able to pass each other in the Y direction along the linear bearings 12a, 12b.

[0031] To provide space for the downward camera 50, the spindle assemblies may extend from the respective placement head beams (i.e., the first and second beams 14a, 14b) toward the camera beam (i.e., the third beam 14c) such that the spindles 18a, 18b can be positioned below the downward camera 50 when the beams are close to each other. For example, the first spindle 18a can be positioned directly below the downward camera 50 when the first beam 14a is close to the third beam 14c, and the second spindle 18b can be positioned directly below the downward camera 50 when the second beam 14b is close to the third beam 14c.

[0032] The extensions of each of the spindles 18a, 18b hold nozzles 28a, 28b mounted vertically between the centers of two horizontal glass plates 18a, 18b to allow a downward-looking camera 50 on the third beam 14c to be positioned above the glass plates to image the outer edges of the gripped device during the actual placement operation and active alignment of the outer edges of the gripped device with targets on the substrate 34.

[0033] The first and second piezoelectric element stages 20a, 20b may be configured to finely adjust the positioning of the first and second spindles 18a, 18b in six axes, including the X-axis, Y-axis, Z-axis, θ rotational axis, α rotational axis, and β rotational axis. The X-axis direction may be parallel to the X-axes 15a, 15b, and 15c, the Y-axis direction may be parallel to the Y-axes 13a and 13b, and the Z-axis direction may be parallel to the Z-axes 24a and 24b. The α rotation direction may be rotation about an axis parallel to the X-axes 15a, 15b, and 15c, the β rotation direction may be rotation about an axis parallel to the Y-axes 13a and 13b, and the θ rotation direction may be rotation about an axis parallel to the Z-axes 24a and 24b.

[0034] For final alignment, a six-degree-of-freedom piezoelectric actuator-driven stage is mounted between the Z-drive of the PH beam carriage and the placement head and / or spindle assembly, allowing for precise positioning adjustments based on spindle camera information of the difference between the target positioning and the device's actual positioning, while moving slowly in small steps relative to the substrate. The piezoelectric stage described here allows for submicron alignment of the device on the nozzle tip relative to the spindle camera and substrate, not only in the X, Y, and Z axes, but also in the theta, alpha, and beta angles. Angle adjustment is required to achieve more precise theta than existing theta servo drives. The alpha and beta adjustments allow for improved flush contact of the device on the substrate by preventing crushing of corner interconnect features on the device or substrate.

[0035] Piezoelectric stages 20a, 20b of placement heads 25a, 25b may each include a respective motion controller housed within the body of the piezoelectric stage 20a, 20b. The motion controller may each be a computer system or processor located within the piezoelectric stage that includes the capability to receive and process signals from motion sensors within electronic device placement system 10. For example, the motion controller may include a processor, at least one memory device, and / or at least one data storage system. The motion controller may also include a signal receiver, which may be wired or wireless in various embodiments.

[0036] In particular, the motion controller may be connected to respective spindle accelerometer systems 90, 91 attached to the spindles 18a, 18b of the respective placement heads 25a, 25b. The spindle accelerometer systems 90, 91 may be configured to measure vibrations of the respective spindles 18a, 18b and / or their nozzles 28a, 28b in both the X and Y directions. These measurements may be provided in real time to the motion controller of the respective piezoelectric stages 20a, 20b for processing.

[0037] Additionally, a substrate accelerometer system 92 may be mounted to the substrate support 41. The substrate accelerometer system 92 may be proximate to the transducer 93 and may be configured to measure vibrations in the substrate support 41 in both the X and Y directions. Like the spindle accelerometer systems 90 and 91, the substrate accelerometer system 92 may also be communicatively connected to the motion controllers of each of the piezoelectric stages 20 a and 20 b.

[0038] Each of the spindle accelerometer systems 90, 91 may include one or more accelerometers. For example, the spindle accelerometer systems 90, 91 may include a first accelerometer device configured to measure vibrations of the respective spindle 18a, 18b in the X direction and a second accelerometer device configured to measure vibrations of the respective spindle 18a, 18b in the Y direction. Thus, a respective set of accelerometers for each of the X and Y directions may be rigidly mounted near the respective spindle 18a, 18b and / or nozzle 28a, 28b to measure vibrations of the respective spindle 18a, 18b and / or nozzle 28a, 28b.

[0039] Similarly, the substrate accelerometer system 92 may include a first accelerometer device configured to measure vibrations of the substrate support in the X direction and a second accelerometer device configured to measure vibrations of the substrate support in the Y direction. Accordingly, the set of accelerometers may be rigidly attached to the substrate support 41 that holds the substrate 34 to measure vibrations of the substrate 34.

[0040] Using the signals and the information received by the accelerometer systems 90, 91, and 92, the motion controllers of the piezoelectric stages 20a and 20b, respectively, may be configured to eliminate relative motion between the spindle and the substrate support. Additionally, the piezoelectric stages 20a and 20b may each be configured to account for beam vibrations, controller system fan vibrations, and external system vibrations. The motion controllers may be configured to operate the respective piezoelectric stages 20a and 20b of the placement heads 25a and 25b to adjust the nozzle movement corresponding to the substrate support 41 movement to reduce the relative motion between the placement heads 25a and 25b and the piezoelectric stages 20a and 20b. Processing of both sets of signals (from the spindle accelerometer system and the substrate accelerometer system) allows the piezoelectric stages 20a and 20b to vibrate the nozzles 28a and 28b in exactly the same direction and with the same magnitude as the vibrations of the substrate 34. This eliminates relative movement between the devices 32a, 32b on the nozzle tip and the substrate 34, allowing sub-micron placement.

[0041] As described above, in exemplary embodiments herein, the electronic device placement system and method uses one or more cartesian positioning system beams in an electronic device placement assembly apparatus or system. The beams disclosed herein are configured to move along the same linear bearing in the Y direction, allowing a carriage to move along each beam in the X direction. A camera beam holds a spindle camera in a vertically downward position. This camera may image the substrate and, using a vision system, determine the positioning of interconnect features on the substrate that are targets for the device being placed. The cartesian positioning systems described herein may be constructed of steel or similar rigid metallic materials and may further include standard ball bearings.

[0042] 3A shows a schematic side view of an electronic device placement system 200 including a downward-looking camera 250 and a spindle 218 of a placement head 219 having a nozzle 228 for grasping an electronic device 228 out of the visual path of the downward-looking camera 250, according to one embodiment. FIG. 3B shows a schematic side view of an electronic device placement system 200 including a downward-looking camera 250 and having a nozzle 228 for grasping an electronic device 228 above a substrate 234, according to one embodiment.

[0043] While not shown, electronic device positioning system 200 may also include a positioning system having a pair of linear bearings, such as linear bearings 12a and 12b, and at least one beam, such as one of beams 14a, 14b, and 14c. A carriage 216 is shown on the beam to which both downward-looking camera 250 and spindle 218 are movably coupled. Accordingly, the beam in this embodiment may be movably coupled to at least one bearing disposed along an X-axis perpendicular to the Y-axis. The beam may be configured to move relative to the at least one linear bearing along the Y-axis to achieve movement in the X and Y directions. Carriage 216 may be movably coupled to the beam and configured to move relative to the beam along the X-axis.

[0044] The electronic device positioning system 200 includes a spindle assembly Z-drive 222 movably coupled to a carriage 216 configured to move relative to the carriage along a Z-axis, which is perpendicular and orthogonal to the X-axis and Y-axis, respectively. Similarly, a spindle 218 is coupled to the spindle assembly Z-drive 222. The spindle may be the same as or similar to the spindles 18a and 18b described above. As shown, the spindle 218 includes a nozzle 228 mounted vertically on a transparent spindle body. The transparent spindle body includes two glass plates 226. As shown, the spindle 218 includes a θ-drive 230 for rotating the spindle 218 and the nozzle 228.

[0045] Alternatively, although not shown, electronic device placement system 200 may include a camera, such as one of upward-facing cameras 36, 38 described above, that faces upward and is configured to image the bottom surface of electronic device 232. Electronic device placement system 200 may include only a single upward-facing camera in this single-spindle embodiment. The device camera may be configured to image electronic device 232 grasped by nozzle 228 of spindle 218 prior to the placement operation of electronic device 232.

[0046] As shown in FIG. 3B , electronic device positioning system 200 includes a downward-looking camera 250 movable over spindle 218 during positioning of electronic device 232 by spindle 218. Downward-looking camera 250 is configured to image the outer edge of electronic device 232 through a transparent spindle body during the positioning operation of spindle 218. Downward-looking camera 250 may include a lens and / or lighting system to facilitate accurate imaging. Downward-looking camera 250 may include a camera Z-drive 252 movably coupled to carriage 216 configured to move relative to the carriage in the Z-axis. Thus, downward-looking camera 250 and spindle 218 may be movably coupled to the same carriage 216 in the illustrated embodiment. However, the downward-looking camera may be movable independently of spindle 218 relative to carriage 216 in the Z-axis. Thus, spindle 218 and downward-looking camera 250 each include a separate Z-drive 222, 252 dedicated for independent movement.

[0047] As shown in FIG. 3A , spindle 218 may be configured to move out of the viewing path of downward-looking camera 250 along a travel path M when the spindle camera is pointed in the deployed position. In the illustrated embodiment, spindle 218 may be configured to be hinged and rotatable relative to carriage 216. However, in other embodiments, spindle 218 may be movable relative to carriage 216 along a spindle linear bearing (not shown) to move out from below downward-looking camera 250 and allow direct imaging of substrate 234 by downward-looking camera 250. Spindle 218 may be movable relative to downward-looking camera 250 by at least one degree of freedom. Alternatively, spindle 218 may be movable relative to downward-looking camera 250 by at least two degrees of freedom (i.e., independent vertical movement and independent horizontal movement).

[0048] Additionally, while not shown, electronic device positioning system 200 includes an equipment frame and a substrate retention system similar to the above-described equipment frame 40, substrate support 41, and substrate retention system 42. In particular, electronic device positioning system 200 includes substrate support 241 having substrate retention system 242 for holding substrate 234.

[0049] Electronic device positioning system 200 further includes a piezoelectric stage 220 movably coupled between spindle assembly Z-drive 222 and spindle 218. Piezoelectric stage 220 is configured to move spindle 218 relative to spindle assembly Z-drive 222 to provide fine adjustments to the positioning of spindle 218. Similar to piezoelectric stages 20a and 20b described above, the piezoelectric stage is configured to provide fine adjustments to the positioning of the spindle in six axes, including the X-axis, Y-axis, Z-axis, the θ rotational axis, the α rotational axis, and the β rotational axis.

[0050] The piezoelectric stage 220 of the placement head 219 may include a motion controller housed within the body of the piezoelectric stage 219. The motion controller may be a computer system or processor located within the piezoelectric stage 219 that includes the capability to receive and process signals from motion sensors in the electronic device placement system 200. For example, the motion controller may include a processor, at least one memory device, and / or at least one data storage system. The motion controller may further include a signal receiver, which may be wired or wireless in various embodiments.

[0051] In particular, the motion controller may be connected to a spindle accelerometer system 290 attached to the placement head 219 and its spindle 218. The spindle accelerometer system 290 may be configured to measure vibrations of the spindle 218 and / or its nozzle 228 in both the X and Y directions. These measurements may be provided in real time to the motion controller of the piezoelectric stage 220 for processing.

[0052] Additionally, a substrate accelerometer system 292 may be mounted to the substrate support 241. The substrate accelerometer system 292 may be in close proximity to a transducer 293 and may be configured to measure vibrations in the substrate support 241 in both the X and Y directions. Like the spindle accelerometer system 290, the substrate accelerometer system 292 may also be communicatively connected to the motion controller of the piezoelectric stage 220.

[0053] The spindle accelerometer system 290 may include one or more accelerometers. For example, the spindle accelerometer system 290 may include a first accelerometer device configured to measure vibrations of the spindle 218 in the X direction and a second accelerometer device configured to measure vibrations of the spindle 218 in the Y direction. Accordingly, a respective set of accelerometers for each of the X and Y directions may be rigidly mounted near the spindle 218 and / or nozzle 228 of the placement head 200 to measure vibrations of the spindle 218 and / or nozzle 228.

[0054] Similarly, the substrate accelerometer system 292 may include a first accelerometer device configured to measure vibrations of the substrate support in the X direction and a second accelerometer device configured to measure vibrations of the substrate support in the Y direction. Accordingly, this set of accelerometers may be rigidly attached to the substrate support 241 that holds the substrate 234 to measure vibrations of the substrate 234.

[0055] Using the signals and the information received by the accelerometer systems 290, 292, the motion controller of the piezoelectric stage 220 may be configured to eliminate relative motion between the spindle and the substrate support. Additionally, the motion controller of the piezoelectric stage 220 may be configured to take into account beam vibrations, controller system fan vibrations, and external system vibrations. The motion controller may be configured to operate the piezoelectric stage 220 of the placement head 219 to adjust the movement of the nozzle 228 and / or spindle 218 to correspond to the movement of the substrate support 241 and / or substrate 243 to reduce relative motion between the substrate support 241 and the substrate 243. Processing of both sets of signals (from the spindle accelerometer system and the substrate accelerometer system) allows the piezoelectric stage 220 to vibrate the nozzle 228 to the same extent and in exactly the same direction as the vibration of the substrate 234. This eliminates relative motion between the device 232 on the nozzle tip and the substrate 234, enabling sub-micron placement.

[0056] As described above, in exemplary embodiments herein, the electronic device placement system and method uses one or more cartesian positioning system beams in an electronic device placement assembly apparatus or system. The beams disclosed herein are configured to move along the same linear bearing in the Y direction, allowing a carriage to move along each beam in the X direction. A camera beam holds a spindle camera in a vertically downward position. This camera may image the substrate and, using a vision system, determine the location of interconnect features on the substrate that are targets for the device being placed. The cartesian positioning systems described herein may be constructed of steel or similar rigid metallic materials and may further include standard ball bearings.

[0057] In the various embodiments described above, the sequence of motions may be as follows: First, the positioning system may perform all large-scale movements in X, Y, and θ. When the positioning system moves the placement head, spindle assembly, and / or its nozzle into position to place a component, the beam, placement head, and spindle assembly with nozzle may still vibrate. Similarly, the substrate held on the substrate support may also vibrate due to external vibrations such as beam vibration, control system fan vibration, or foot traffic near the device. Accelerometers in the placement head system and in the substrate holder detect all different frequency vibration sources, regardless of their origin. The piezoelectric stage motion controller or control system provides near-instantaneous motion, which may be capable of eliminating nearly all relative motion by moving the nozzle synchronously with the substrate. This allows for alignment of the nozzle tip device with a target on the substrate.

[0058] 4 shows a graphical representation of acceleration patterns over time, before synchronous motion damping, caused by vibrations in the X and Y directions and measured by both the spindle and substrate support accelerometer systems, according to one embodiment. In particular, graph 400 includes a first acceleration pattern 402 of the placement head's spindle in the X direction over time. Graph 400 also includes a second acceleration pattern 404 of the substrate's spindle in the X direction over time. Additionally, graph 450 includes a third acceleration pattern 452 of the placement head's spindle in the Y direction over time. Graph 450 also includes a second acceleration pattern 454 of the substrate in the Y direction over time. As explained above, the various patterns 402, 404, 452, and 454 are provided prior to synchronous motion control and damping. The various patterns 402, 404, 452, and 454 may be representations of data requested by the motion controller of the piezoelectric stage of the placement head from the accelerometer systems of the placement head and substrate support before the piezoelectric stage applies synchronized motion control and damping, as described above, in accordance with the embodiments described herein.

[0059] 5 shows a graphical representation of acceleration patterns over time after synchronous motion damping caused by vibrations in the X and Y directions as measured by both the spindle and substrate support accelerometer systems, according to one embodiment. In particular, graph 500 includes a first acceleration pattern 502 of the placement head's spindle in the X direction over time. Graph 500 also includes a second acceleration pattern 504 of the substrate's spindle in the X direction over time. Additionally, graph 550 includes a third acceleration pattern 552 of the placement head's spindle in the Y direction over time. Graph 550 also includes a second acceleration pattern 554 of the substrate in the Y direction over time. As discussed above, the various patterns 502, 504, 552, and 554 are provided after synchronous motion control and damping. The various patterns 402, 404, 452, and 454 may be representations of data requested by the placement head piezoelectric stage motion controller from the spindle and substrate support accelerometer systems after the piezoelectric stage has applied synchronous motion control and damping according to the embodiments described herein, as described above.

[0060] 6 illustrates, in one embodiment, a method 600 for positioning an electronic device, such as electronic device 32a, 32b, or 232. Method 600 includes a first step 602 of providing an electronic assembly system, such as one of electronic assembly systems 10, 200, having a piezoelectric stage, such as one of piezoelectric stages 20a, 20b, or 200, where the piezoelectric stage includes a motion controller. Method 600 includes a step 604 of receiving a signal from at least one accelerometer or accelerometer system, such as accelerometer system 90, 91, or 290, mounted on a spindle, such as one of spindles 18a, 18b, or 218, of a placement head, such as placement head 25a, 25b, or 219.

[0061] Method 600 may include various steps that may be performed by a motion controller of a piezoelectric stage of the placement head. For example, method 600 includes step 606 of receiving a signal from an accelerometer system, such as one of accelerometer systems 92, 292, mounted on a substrate support, such as one of substrate supports 41, 241. Method 600 includes step 608 of processing signals from the accelerometer system of the spindle and the accelerometer system mounted on the substrate support. Step 608 may be performed by a motion control system located in the piezoelectric stage of the placement head. Method 600 may include step 610 of measuring vibrations of the spindle in both the X and Y directions. Step 610 may also be performed by a motion controller of the piezoelectric stage of the placement head. Method 600 may further include step 611 of measuring vibrations of the substrate support in both the X and Y directions.

[0062] Method 600 may include step 612 of synchronizing relative motion between the spindle and the substrate attached to the substrate support caused by at least one vibration. Step 612 may be performed by a motion controller for a piezoelectric stage of the placement head. Method 600 may include step 614 of reducing or eliminating relative motion between the spindle and the substrate support. Step 614 may be performed by a motion controller for a piezoelectric stage of the placement head. Method 600 may further include step 616 of taking into account beam vibrations, controller system fan vibrations, and external system vibrations. Step 614 may be performed by a motion controller for a piezoelectric stage of the placement head.

[0063] The methods described herein may comprise positioning an electronic device gripped by a nozzle of the described spindle assembly with an accuracy of 1 micron or better. The embodiments described herein allow low-cost devices fabricated with steel positioning systems and standard ball bearings to achieve accuracy comparable to or better than granite block devices with ceramic beams on air bearings. The embodiments described herein allow for even higher speeds because they reduce or eliminate settling times that significantly slow state-of-the-art high-precision devices. The embodiments described herein may further reduce costs in device manufacturing by eliminating the need for separate control cabinets and damping floor materials or by diverting any traffic within the device away from state-of-the-art devices. Various other advantages may be realized through application of the concepts provided herein.

[0064] While the above embodiments are illustrative, it is contemplated that multiple spindle assemblies or spindles may be mounted on a single piezoelectric stage in various other embodiments. Furthermore, while the accelerometer systems described above are described as measuring and taking into account acceleration in both the X and Y directions, these two directions may be illustrative. For example, if X and Y are horizontal axes, Z is a vertical axis, and α, β, and θ are rotational axes, a transducer including an accelerometer and an angular rate gyroscope may be used to compensate for and synchronize the motion of any or all of the X, Y, Z, α, β, and θ vibrations.

[0065] Elements of the embodiments are described with either the article "a" or "an." The article is intended to mean there are one or more elements. The terms "comprise," "have," and their derivatives are intended to be inclusive so that there may be additional elements other than the listed elements. The conjunction "or," used with a list of at least two terms, is intended to refer to any term or combination of terms. The terms "first" and "second" are used to distinguish between elements and not to denote a particular order.

[0066] While the present invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the present invention is not limited to such disclosed embodiments. Rather, the present invention may be modified to incorporate any number of variations, modifications, substitutions, or equivalent arrangements not heretofore described, yet still falling within the spirit and scope of the claims of the present invention. Additionally, while various embodiments of the present invention have been described, it is to be understood that aspects of the present invention may include only some of the described embodiments. Accordingly, the present invention is not to be deemed limited by the above description, but is limited only by the scope of the appended claims.

Claims

1. A spindle and a positioning system configured to move the spindle between a gripping position and a placement position; a spindle assembly Z drive; a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage including a motion controller configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the positioning of the spindle; a spindle accelerometer system connected to the motion controller of the piezoelectric stage, the spindle accelerometer system configured to measure vibrations in an X direction and a Y direction; a placement head including: a substrate support configured to hold a substrate that is a target for placement of electronic components by the spindle; a substrate accelerometer system mounted to the substrate support, the substrate accelerometer system configured to measure vibrations in the X and Y directions, the substrate accelerometer system connected to the motion controller of the piezoelectric stage; 1. An electronic assembly system comprising:

2. 2. The electronic assembly system of claim 1, wherein the spindle accelerometer system includes a first accelerometer configured to measure vibrations of the spindle in the X direction and a second accelerometer configured to measure vibrations of the spindle in the Y direction.

3. 3. The electronic assembly system of claim 2, wherein the substrate accelerometer system includes a first accelerometer configured to measure vibrations of the substrate support in the X direction and a second accelerometer configured to measure vibrations of the substrate support in the Y direction.

4. 10. The electronic assembly system of claim 1, wherein the piezoelectric stage is configured to provide fine adjustment to the positioning of the spindle in six axes, including an X axis, a Y axis, a Z axis, a theta rotation axis, an alpha rotation axis, and a beta rotation axis.

5. 5. The electronic assembly system of claim 4, wherein the motion controller of the piezoelectric stage is configured to process signals from each of the spindle and substrate accelerometer systems.

6. The electronic assembly system of claim 5 , wherein the motion control device is configured to eliminate relative vibratory motion between the spindle and the substrate support.

7. 7. The electronic assembly system of claim 6, wherein the motion controller of the piezoelectric stage is configured to take into account beam vibrations, control system fan vibrations, and external system vibrations.

8. 10. The electronic assembly system of claim 1, wherein said positioning system is made of steel and uses linear ball bearings.

9. A spindle and a positioning system configured to move the spindle between a gripping position and a placement position; a spindle assembly Z drive; a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage including a motion controller configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the positioning of the spindle; a spindle accelerometer system connected to the motion controller of the piezoelectric stage and configured to measure vibrations in the X and Y directions; 1. A placement head for an electronic assembly system comprising:

10. 10. The placement head of claim 9, wherein the spindle accelerometer system includes a first accelerometer configured to measure vibration of the spindle in the X direction and a second accelerometer configured to measure vibration of the spindle in the Y direction.

11. 10. The placement head of claim 9, wherein the piezoelectric stage is configured to provide fine adjustment to the positioning of the spindle in six axes, including an X axis, a Y axis, a Z axis, a theta rotation axis, an alpha rotation axis, and a beta rotation axis.

12. The placement head of claim 11 , wherein the motion controller of the piezoelectric stage is connectable to a substrate accelerometer system mounted on a substrate support of the electronic assembly system.

13. The placement head of claim 12 , wherein the motion controller of the piezoelectric stage is configured to process signals from each of the spindle and the substrate accelerometer systems.

14. The placement head of claim 13 , wherein the motion controller of the piezoelectric stage is configured to reduce or eliminate relative vibratory motion between the spindle and the substrate support.

15. 15. The placement head of claim 14, wherein the motion controller of the piezoelectric stage is configured to take into account nozzle vibrations, beam vibrations, control system fan vibrations, and external system vibrations.

16. A spindle and a positioning system configured to move the spindle between a gripping position and a placement position; a spindle assembly Z drive; a piezoelectric stage movably coupled between the spindle assembly Z-drive and the spindle, the piezoelectric stage including a motion controller configured to move the spindle relative to the spindle assembly Z-drive to make fine adjustments to the positioning of the spindle; a spindle accelerometer system connected to the motion controller of the piezoelectric stage, the spindle accelerometer system configured to measure vibrations in an X direction and a Y direction; a placement head including: a substrate support configured to hold a substrate that is a target for placement of electronic components by the spindle; a substrate accelerometer system mounted on the substrate support, the substrate accelerometer system configured to measure vibrations in the X and Y directions, the substrate accelerometer system connected to the motion controller of the piezoelectric stage; an electronic assembly system including: receiving, by the motion controller of the piezoelectric stage, signals from the spindle accelerometer system; receiving signals from the substrate accelerometer system by the motion controller of the piezoelectric stage; processing signals from each of the spindle accelerometer system and the substrate accelerometer system by the motion controller of the piezoelectric stage; synchronizing relative vibrational motion between the spindle and a substrate mounted on the substrate support caused by at least one vibration by the motion controller of the piezoelectric stage; 1. A method for synchronizing a spindle head for vibration damping, comprising:

17. The method of claim 16, further comprising measuring vibrations of the spindle in both the X and Y directions.

18. 17. The method of claim 16, further comprising receiving, by the motion controller of the piezoelectric stage, signals from each of a first accelerometer and a second accelerometer of the spindle accelerometer system.

19. 17. The method of claim 16, further comprising reducing or eliminating relative motion between the spindle and the substrate support with the motion controller of the piezoelectric stage.

20. 20. The method of claim 17, further comprising: the motion controller of the piezoelectric stage taking into account nozzle vibrations, beam vibrations, control system fan vibrations, and external system vibrations.

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