Air floating leveling device and bonding method

Abstract

This invention relates to an air-float leveling device and a bonding method. The air-float leveling device includes a connecting seat, a leveling seat, and multiple adjusting components. The leveling seat is used to mount the bonding head and is disposed on the connecting seat. The leveling seat has multiple spaced mounting points on its circumference, and each mounting point corresponds to a reference point at a different position on the end face of the bonding head. The multiple adjusting components are respectively disposed at the multiple mounting points on the leveling seat, and each adjusting component is independently controlled. The connecting seat and the leveling seat have a leveling state and a locked state. In the leveling state, an air film is formed between the connecting seat and the leveling seat, surrounding the circumference of the leveling seat, so that each adjusting component can drive the reference point corresponding to the end face of the bonding head to adaptively rise and fall through the leveling seat. In the locked state, the connecting seat locks the leveling seat in the current position.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to an air-float leveling device and bonding method. Background Technology

[0002] Traditional air-float leveling devices mostly employ single-motor driven lead screws, cams, or wedges as mechanical fine-tuning mechanisms, combined with conventional displacement sensors such as ordinary grating rulers to achieve position closed-loop control. This approach suffers from a core, insurmountable flaw: the kinematic chain is constrained by a single drive source and mechanical transmission, resulting in extremely limited degrees of freedom for active compensation. This makes it difficult to perform multi-axis independent decoupling fine-tuning of the bonding head's spatial attitude (pitch, roll, etc.). If asymmetric warping or initial parallelism deviation exists between the chip and the substrate, single-degree-of-freedom leveling cannot homogenize the interface gap, easily leading to localized force imbalances in the bonding area. This results in significantly uneven stress on microbumps, thereby significantly amplifying fatal process risks such as poor soldering, bridging, bump cracking, and microcracks in ultra-thin chips. Summary of the Invention

[0003] Therefore, it is necessary to provide an air-floating leveling device and bonding method that can achieve multi-degree-of-freedom attitude correction of the bonding head.

[0004] An air flotation leveling device includes: a connecting seat; a leveling seat for mounting a bonding head, the leveling seat being disposed on the connecting seat, the leveling seat having a plurality of spaced mounting points circumferentially distributed, the plurality of mounting points of the leveling seat corresponding one-to-one with a plurality of reference points at different positions on the end face of the bonding head; a plurality of adjusting components, each disposed at a plurality of mounting points of the leveling seat, each adjusting component being independently controlled; the connecting seat and the leveling seat having a leveling state and a locked state; in the leveling state, an air film is formed between the connecting seat and the leveling seat surrounding the periphery of the leveling seat, so that each adjusting component can drive the reference point corresponding to the end face of the bonding head to adaptively rise and fall through the leveling seat; in the locked state, the connecting seat locks the leveling seat in the current position.

[0005] In one embodiment, the bottom of the connecting seat is provided with a spherical groove, and a plurality of air holes are spaced apart on the groove surface; the top of the leveling seat has a convex spherical surface, which is fitted into the spherical groove; the bottom of the leveling seat is connected to a key head; in the leveling state, an air film is formed between the groove surface of the spherical groove and the convex spherical surface; in the locked state, the convex spherical surface can be tightly attached to the groove surface of the spherical groove.

[0006] In one embodiment, the air flotation leveling device further includes a detection unit, which includes multiple detection elements, each of which is used to detect the height data of different reference points corresponding to the bonding head.

[0007] In one embodiment, a plurality of the detection elements are arranged in a ring at circumferential intervals along the connecting seat, and each of the plurality of detection elements corresponds one-to-one with a plurality of the adjustment components.

[0008] In one embodiment, the air flotation leveling device is equipped with three detection elements and three adjustment components. The three adjustment components are arranged in a 120° equally spaced ring along the circumference of the leveling seat, and the three detection elements are arranged in a 120° equally spaced ring along the circumference of the connecting seat. The three detection elements are used to collect the reference point height data of three different positions on the end face of the bonding head in real time.

[0009] In one embodiment, the adjustment assembly includes a voice coil motor and a transmission component. The stator of the voice coil motor is connected to the connecting base via a bracket. The output end of the mover of the voice coil motor is connected to the input end of the transmission component. The output end of the transmission component is connected to the corresponding mounting point on the leveling base. The driving direction of the voice coil motor is consistent with the leveling movement direction of the leveling base.

[0010] In one embodiment, the air flotation leveling device further includes a guide assembly, and the output end of the transmission component is connected to the leveling seat through the guide assembly.

[0011] In one embodiment, a tension spring assembly is provided between the leveling seat and the connecting seat.

[0012] A bonding method based on the above-mentioned air flotation leveling device, the bonding method comprising the following steps: S10. Switch the connecting seat and the leveling seat to the leveling state to establish an unconstrained leveling condition; S20. Based on the height data of each reference point on the end face of the bonding head detected by the detection unit, the control system fits the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head, calculates the compensation displacement required for each reference point on the end face of the bonding head, and sends corresponding adjustment commands to each of the adjustment components; S30. Each adjustment component drives the reference point corresponding to the end face of the bonding head to move through the leveling seat, so as to actively adjust the height of each reference point corresponding to the end face of the bonding head.

[0013] In one embodiment, the bonding method further includes: S50. Switching the connector and the leveling seat to a locked state, so that the connector locks the leveling seat in the current leveling position.

[0014] The air-floating leveling device provided by this invention, in the leveling state, introduces compressed air into the mating surface between the connecting seat and the leveling seat, forming an air film surrounding the leveling seat, thus placing the leveling seat in a non-contact suspension state. At this time, the leveling seat obtains extremely low frictional resistance in all directions of movement, enabling frictionless micro-displacement relative to the connecting seat under the drive of any adjustment component. This, in turn, causes the corresponding reference points on the end face of the bonding head to adaptively rise and fall. Furthermore, when multiple adjustment components work together, the spatial attitude deviation of the bonding head can be calculated and multi-degree-of-freedom precision correction can be completed by independently adjusting the height of each reference point. When switching to the locked state, the air source is turned off, the air film dissipates, the leveling seat falls back and directly contacts the connecting seat, or is securely locked in the current position by an auxiliary locking mechanism (such as vacuum adsorption, electromagnetic locking, or mechanical clamping), providing high-rigidity and stable support for subsequent bonding processes.

[0015] During leveling, an external detection unit continuously monitors the height data of multiple reference points at different locations on the end face of the bonding head. The external control system uses the height data fed back by the detection unit to fit the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head, calculates the required compensation displacement for each reference point on the end face of the bonding head, and sends corresponding adjustment commands to each adjustment component. The driving direction of the adjustment component is consistent with the leveling motion direction of the leveling seat, that is, it generates linear motion along the axial direction of the leveling seat (or perpendicular to the end face of the bonding head). The installation point of the adjustment component is connected to the leveling seat. The axial thrust and displacement output by the adjustment component are directly transmitted to the corresponding installation point of the leveling seat, driving the leveling seat to move up and down along the same axial direction at that installation point. Each adjustment component is independently controlled, and each adjustment component drives the end face of the bonding head through the leveling seat. The corresponding reference point movement enables active adjustment of the height of each reference point on the end face of the bonding head, achieving precise point-to-point correction: For reference points that are too high, the corresponding adjustment component moves the corresponding reference point of the bonding head downward through the leveling seat, causing the reference point to accurately fall back; for reference points that are too low, the corresponding adjustment component moves the corresponding reference point of the bonding head upward through the leveling seat, enabling precise support compensation (i.e., pushing upward to achieve height correction). In this way, through the coordinated cooperation of multiple adjustment components, the multi-degree-of-freedom attitude correction of the bonding head is achieved, gradually correcting the flatness error and two-dimensional tilt angle error of the end face of the bonding head. Through repeated iterative detection and correction, until the flatness of the end face of the bonding head and its parallelism relative to the reference surface both reach the preset high-precision threshold, the active correction and leveling of the bonding head is completed. Attached Figure Description

[0016] Figure 1 A schematic diagram of the structure of the air flotation leveling device provided in an embodiment of the present invention; Figure 2 A cross-sectional view of an air flotation leveling device provided in an embodiment of the present invention; Figure 3 An exploded view of the air flotation leveling device provided in an embodiment of the present invention. Detailed Implementation

[0017] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0018] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0020] like Figure 1 and Figure 2 As shown, the present invention provides an air-float leveling device, which realizes the leveling and positioning of the chip before bonding based on air-float technology, and achieves frictionless and vibration-free smooth movement of the chip during the leveling process, thereby ensuring the precise positioning and stability of the chip before bonding, and greatly improving the accuracy and reliability of chip bonding.

[0021] The air flotation leveling device includes a connecting seat 110, a leveling seat 120, and multiple adjusting components 130. The leveling seat 120 is used to install the bonding head 140. The leveling seat 120 is set on the connecting seat 110. The leveling seat 120 has multiple spaced mounting points in its circumference. The multiple mounting points of the leveling seat 120 correspond one-to-one with the reference points at multiple different positions on the end face of the bonding head 140. The multiple adjusting components 130 are respectively set at the multiple mounting points of the leveling seat 120, and each adjusting component 130 is independently controlled.

[0022] Specifically, multiple adjustment components 130 are arranged in a ring around the circumference of the leveling seat 120; the connecting seat 110 and the leveling seat 120 have a leveling state and a locked state; in the leveling state, an air film is formed between the connecting seat 110 and the leveling seat 120, surrounding the leveling seat 120, so that the leveling seat 120 can move relative to the connecting seat 110 under the action of each adjustment component 130, thereby causing the leveling seat 120 to adaptively raise and lower the reference point corresponding to the end face of the bonding head 140; in the locked state, the connecting seat 110 locks the leveling seat 120 in the current position.

[0023] The air-floating leveling device provided by this invention, in the leveling state, introduces compressed air into the mating surface between the connecting seat 110 and the leveling seat 120, forming an air film surrounding the leveling seat 120, thus placing the leveling seat 120 in a non-contact suspension state. At this time, the leveling seat 120 obtains extremely low frictional resistance in all directions of movement, enabling it to achieve frictionless micro-displacement relative to the connecting seat 110 under the drive of any adjustment component 130, thereby causing the corresponding reference point on the end face of the bonding head 140 to adaptively rise and fall. In addition, when multiple adjustment components 130 work together, the spatial attitude deviation of the bonding head 140 can be calculated and multi-degree-of-freedom precision correction can be completed by independently adjusting the height of each reference point. When switching to the locked state, the air source is turned off, the air film dissipates, the leveling seat 120 falls back and directly contacts the connecting seat 110, or is securely locked in the current position by an auxiliary locking mechanism (such as vacuum adsorption, electromagnetic locking, or mechanical clamping), providing high-rigidity stable support for subsequent bonding processes.

[0024] During leveling, an external detection unit continuously monitors the height data of multiple reference points at different positions on the end face of the bonding head 140. The external control system uses the height data fed back by the detection unit to fit the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head 140, calculates the required compensation displacement for each reference point on the end face of the bonding head 140, and sends corresponding adjustment commands to each adjustment component 130. The driving direction of the adjustment component 130 is consistent with the leveling motion direction of the leveling seat 120, that is, it generates linear motion along the axial direction of the leveling seat 120 (or in a direction perpendicular to the end face of the bonding head 140). The installation point of the adjustment component 130 is connected to the leveling seat 120. The axial thrust and displacement output by the adjustment component 130 are directly transmitted to the corresponding installation point of the leveling seat 120, driving the leveling seat 120 to move up and down along the same axial direction at that installation point. Each adjustment component 130 is independently controlled, and each adjustment component 130 is connected to the leveling seat 120. The 20 component moves the reference point corresponding to the end face of the bonding head 140 to actively adjust the height of each reference point corresponding to the end face of the bonding head 140, and perform point-to-point precise correction: For reference points that are too high, the corresponding adjustment component 130 is controlled to move the corresponding reference point of the bonding head 140 downward through the leveling seat 120, so that the reference point falls back precisely; for reference points that are too low, the corresponding adjustment component 130 is controlled to move the corresponding reference point of the bonding head 140 upward through the leveling seat 120, so that the reference point achieves precise support compensation. In this way, through the coordinated cooperation of multiple adjustment components 130, the multi-degree-of-freedom attitude correction of the bonding head 140 is achieved, and the flatness error and two-dimensional tilt angle error of the end face of the bonding head 140 are gradually corrected. Through repeated iterative detection and correction, the flatness of the end face of the bonding head 140 and its parallelism relative to the reference surface both reach the preset high-precision threshold, thus completing the active correction and leveling of the bonding head 140.

[0025] like Figure 2 As shown, specifically, the bottom of the connecting seat 110 is provided with a spherical groove 111, and multiple air holes are spaced apart on the groove wall surface of the spherical groove 111; specifically, the multiple air holes are arranged in a circumferential annular array along the spherical groove 111. The top of the leveling seat 120 has a convex spherical surface 121, which is inserted into the spherical groove 111. The bottom of the leveling seat 120 is connected to a key head 140. In the leveling state, an air film is formed between the groove surface of the spherical groove 111 and the convex spherical surface 121. In the locked state, the convex spherical surface 121 can be tightly attached to the groove surface of the spherical groove 111.

[0026] During leveling, compressed air is injected through the air vents between the groove surface of the spherical groove 111 and the convex spherical surface 121, forming an air film between them. This causes the leveling seat 120 to be suspended under its own gravity, the gravity of the bonding head 140 and the chip, the upward pushing force of atmospheric pressure, and the downward pushing force of the compressed air. In other words, an air film exists between the groove surface of the spherical groove 111 and the convex spherical surface 121.

[0027] After leveling and bonding are completed, the air between the groove surface of the spherical groove 111 and the convex spherical surface 121 is discharged through the air vent. The air film between the groove surface of the spherical groove 111 and the convex spherical surface 121 disappears and the vacuum level increases. The bottom of the leveling seat 120 is subjected to an upward atmospheric pressure that is greater than the weight of the leveling seat 120 itself and the weight of the bonding head 140. This pushes the convex spherical surface 121 of the leveling seat 120 to move toward the spherical groove 111 in the leveled orientation and press it against the groove surface of the spherical groove 111, thereby completing the leveling of the bonding head 140. Subsequent process operations can maintain the above state, thereby ensuring the parallelism of the bonding head 140 to the bonding of the chip and the substrate. After a set number of process operations, the above leveling operation can be performed again to level the bonding head 140 again, in order to further ensure the parallelism of the bonding head 140 to the bonding of the chip and the substrate.

[0028] Specifically, the connecting seat 110 with a spherical groove 111 serves as a support seat, and the leveling seat 120 with a convex spherical surface 121 is used to support the bonding head 140. The two are precisely matched to form a spherical kinematic pair with a high degree of fit. During the leveling stage, compressed air first enters the interior of the connecting seat 110 and is evenly sprayed out from numerous air holes arranged in a ring array along the circumference on the spherical groove 111. An air film is formed between the groove surface of the spherical groove 111 and the convex spherical surface 121 to achieve air-float flexible leveling.

[0029] This air film completely separates the groove surface of the spherical groove 111 from the convex spherical surface 121, thoroughly eliminating the friction and mechanical gap caused by solid contact. This allows the leveling seat 120 to obtain highly sensitive suspension support without constraints in all directions, enabling free two-dimensional angular deflection without obstruction, creating a near-ideal zero-friction working condition for active leveling. After leveling, the system switches to the pneumatic rigid locking mode: the control system cuts off the air source, the air film dissipates rapidly, the air film between the groove surface of the spherical groove 111 and the convex spherical surface 121 disappears and the vacuum level increases. The bottom of the leveling seat 120 is subjected to an upward atmospheric pressure that is greater than the weight of the leveling seat 120 itself and the weight of the bonding head 140. This pushes the convex spherical surface 121 of the leveling seat 120 to move towards the spherical groove 111 in the leveled orientation and press against the groove surface of the spherical groove 111, completing the pneumatic rigid locking. This provides the bonding head 140 with long-term, highly stable posture maintenance.

[0030] Therefore, the air-float leveling device provided by this invention creatively adopts a dual-mode switching technology of air-float flexible leveling and air pressure rigid locking, which takes into account the high flexibility of active leveling and the high stability of operation locking, providing an ideal working condition with zero friction and no gaps for high-precision leveling.

[0031] like Figure 2 and Figure 3 As shown, the air-float leveling device further includes a detection unit, which includes multiple detection elements 150. The detection elements 150 may be, but are not limited to, laser height gauges. The multiple detection elements 150 are spaced apart on the connector 110. Each detection element 150 is used to detect the height data of the reference points at different positions corresponding to the end face of the bonding head 140.

[0032] In one embodiment, multiple detection elements 150 are arranged in a ring at intervals along the circumference of the connecting seat 110. Each detection element 150 corresponds to a different adjustment component 130. Specifically, in this embodiment, the air-float leveling device is equipped with three detection elements 150. The three detection elements 150 are arranged in a ring at equal intervals of 120° along the circumference of the connecting seat 110. The three detection elements 150 are used to collect the reference point height data of three different positions on the end face of the bonding head 140 in real time. The external control system can fit the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head 140 through the above height data to achieve non-contact, full-area high-precision flatness detection of the end face of the bonding head 140, thereby providing accurate data support for the subsequent closed-loop correction of the bonding head 140.

[0033] Furthermore, the air-float leveling device is equipped with three adjustment components 130. These three components 130 are arranged in a ring at 120° intervals along the circumference of the leveling base 120. Each adjustment component 130 is independently controlled and works collaboratively. The external control system uses the height data fed back by the three detection elements 150 to fit the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head 140, calculates the required compensation displacement for the three corresponding reference points on the end face of the bonding head 140, and sends corresponding adjustment commands to each adjustment component 130. Each adjustment component 130 has a built-in high-response, high-rigidity actuator (such as a voice coil motor). It can independently output high-resolution displacement and precise thrust at the micron or even submicron level. By driving the reference point corresponding to the end face of the bonding head 140 through the leveling seat 120, it can actively adjust the height of each reference point corresponding to the end face of the bonding head 140 and perform point-to-point precise correction. Through the coordinated cooperation of the above three adjustment components 130, the flatness error and two-dimensional tilt angle error of the end face of the bonding head 140 are gradually corrected. Through repeated iterative detection and correction, until the flatness of the end face of the bonding head 140 and the parallelism relative to the reference surface both reach the preset high-precision threshold, the active correction and leveling of the bonding head 140 is completed. Thus, under high-speed conditions, it can complete multi-degree-of-freedom, high-precision, and robust active closed-loop correction and leveling.

[0034] like Figure 3 As shown, the adjustment assembly 130 further includes a voice coil motor 131 and a transmission component 132. The stator of the voice coil motor 131 (usually a permanent magnet assembly) is connected to the connecting seat 110 via a bracket 133, so that the stator (i.e., the motor body) and the connecting seat 110 maintain a static relative relationship. The connecting seat 110 serves as a fixed reference for the entire adjustment assembly 130, bears the reaction force generated by the voice coil motor 131, and provides a stable mounting platform.

[0035] The output terminal of the mover (typically a coil assembly) of the voice coil motor 131 is connected to the input terminal of the transmission component 132. When the voice coil motor 131 is energized, the mover moves linearly along its axial direction (i.e., perpendicular to the end face of the bonding head 140), synchronously driving the transmission component 132. The output terminal of the transmission component 132 is connected to the corresponding mounting point on the leveling base 120. This connection point is directly opposite the reference point on the end face of the bonding head 140 and is the execution point where the driving force ultimately acts on the leveling base 120.

[0036] As a high-response, high-resolution direct-drive actuator, the voice coil motor 131 drives in the same direction as the leveling motion of the leveling seat 120, i.e., it generates linear motion along the axial direction of the leveling seat 120 (or in a direction perpendicular to the end face of the bonding head 140). The voice coil motor 131 is connected to the transmission connection point on the leveling seat 120 through the transmission component 132. The transmission component 132 directly transmits the axial thrust and displacement output by the voice coil motor 131 to the corresponding mounting point, driving the leveling seat 120 to perform micron-level or even sub-micron-level lifting and lowering motion along the same axial direction at the mounting point. Each voice coil motor 131 is independently controlled. The external control system calculates and outputs the compensation displacement command required for each reference point based on the real-time detected height data of each reference point. Through the coordinated active adjustment of the height difference of multiple points, the real-time precise correction of the two-dimensional tilt angle error and flatness error of the end face of the bonding head 140 is achieved, thereby completing the multi-degree-of-freedom attitude correction and air-float leveling of the bonding head 140 under high-speed conditions.

[0037] In the leveling state, the connecting seat 110 and the leveling seat 120 are separated by an air film, resulting in no mechanical friction. The thrust generated by the voice coil motor 131 acts on the leveling seat 120 through the transmission component 132, overcoming minor changes in the air film's load-bearing capacity and driving that point to make a slight displacement along the axial direction (perpendicular to the end face of the bonding head 140). Since the stator of the voice coil motor 131 is fixed on the connecting seat 110, the mover, the transmission component 132, and the leveling seat 120 constitute a kinematic chain on the suspended side.

[0038] Multiple adjustment components 130 are independently installed between the connecting seat 110 and the leveling seat 120 according to the above-mentioned link, and are arranged in a circumferential array. The external control system adjusts the output of each voice coil motor 131, so that each transmission component 132 pushes the corresponding point of the leveling seat 120 to produce different lifting and lowering amounts, thereby coordinating to achieve the pitch, roll and overall height adjustment of the leveling seat 120.

[0039] This connection method completely separates the connector 110 and the leveling seat 120, and utilizes the direct-drive high-response characteristics of the voice coil motor 131 and the rigid transmission of the transmission component 132 to achieve high-speed and precise leveling with multiple degrees of freedom.

[0040] like Figure 3 As shown, the above-mentioned air flotation leveling device further includes a guide assembly 160, and the output end of the transmission component 132 is connected to the leveling seat 120 through the guide assembly 160. The function of the guide assembly 160 is as follows: 1. Motion direction constraints; The guide assembly 160 constrains the output motion of the voice coil motor 131 in the required leveling direction of the leveling seat 120 (i.e., along the axial direction of the leveling seat 120 or perpendicular to the end face of the key head 140), so as to avoid unnecessary lateral offset or torsion of the leveling seat 120 due to assembly gaps, load imbalances or minor lateral disturbances in the air-float state, and ensure that each reference point moves up and down only in the predetermined direction.

[0041] 2. Lateral force bearing and decoupling; During the leveling process, the driving force output by each adjustment component 130 will generate a lateral component due to the height difference at each point. The guide component 160 bears these lateral loads and transmits them to the connecting seat 110, thereby protecting the mover of the voice coil motor 131 and the transmission component 132, so that the voice coil motor 131 only bears the axial load, realizing the structural decoupling of axial drive and lateral force, and ensuring that the voice coil motor 131 always operates under conditions of low lateral load and high linear accuracy.

[0042] 3. Improve transmission stiffness and accuracy; The guide assembly 160 can adopt high-rigidity precision guide rails (such as cross roller guide rails, air-bearing guide rails, etc.) and flexible hinge guide mechanisms to provide gapless or micro-gap guide paths for each mounting point of the leveling seat 120, effectively improving the overall rigidity and motion resolution of the transmission chain, so that the micron-level displacement output by the voice coil motor 131 can be transmitted to the leveling seat 120 without hysteresis or backlash, thereby achieving higher precision reference point height control.

[0043] 4. Parallel guidance of multiple sets of coordinated movements; Since multiple adjustment components 130 are arranged in a ring around the leveling seat 120 and driven independently, the guide component 160 needs to coordinate the movements of each group at the global level to provide complete multi-degree-of-freedom guide constraints for the leveling seat 120, so that the lifting and lowering movements of each reference point do not interfere with each other, while supporting the leveling seat 120 to complete multi-degree-of-freedom attitude corrections such as pitch, roll and overall height compensation under the coordinated drive of multiple voice coil motors 131.

[0044] In summary, the guide assembly 160, as a key component connecting the actuator and the leveling seat 120 in the air flotation leveling device, not only ensures the directional accuracy and motion stability of the drive, but also provides a reliable mechanical guiding foundation for realizing multi-degree-of-freedom active closed-loop correction.

[0045] like Figure 1 As shown, a tension spring assembly 170 is further provided between the leveling seat 120 and the connecting seat 110. The tension spring assembly 170 provided between the leveling seat 120 and the connecting seat 110 mainly serves the following key functions: 1. Provides axial preload to enhance air film stiffness; In the leveling state, the air film suspends the leveling seat 120, and the tension spring assembly 170 applies a certain constant tension along the axial direction (perpendicular to the end face of the bonding head 140) to pull the leveling seat 120 toward the connecting seat 110. This tension and the bearing capacity of the air film form a pair of balanced forces, so that the leveling seat 120 has a smaller displacement when subjected to bonding reaction force or inertial force, thereby improving the leveling accuracy and dynamic stability.

[0046] 2. Power failure or gas loss protection and automatic reset; When the air flotation leveling device experiences a sudden power outage or air supply interruption, the air film dissipates rapidly. At this time, the tension spring assembly 170 provides continuous tension, which smoothly pulls the leveling seat 120 back and tightly adheres it to the connecting seat 110, preventing impact collisions caused by gravity or inertia and protecting the key head 140, voice coil motor 131, and precision guide components. Simultaneously, this action also automatically returns the leveling seat 120 to a safe "zero position" locked state, requiring no additional active return control.

[0047] 3. To compensate for gravity or off-center loads and achieve force balance; If the direction of gravity of the bonding head 140 and the leveling seat 120 is opposite to the direction of the air film bearing force (e.g., when placed vertically), the tension spring assembly 170 can share part of the gravity, so that the voice coil motor 131 only needs to output a small correction force during the leveling process, reducing motor heat loss and improving dynamic response. Under the condition of fixed off-center load, the tension spring assembly 170 can also be designed to balance the off-center load, so that the operating points of each voice coil motor 131 tend to be symmetrical, which is beneficial for multi-point coordinated control.

[0048] 4. Rigid fixation in the assisted locking state; In the locked state, although the air film has dissipated and the leveling seat 120 is in contact with the connecting seat 110, contact alone may not be sufficient to resist vibrations or impacts during the process. The tension of the tension spring assembly 170 can continuously press the leveling seat 120 against the positioning surface of the connecting seat 110, which, together with vacuum adsorption or electromagnetic locking, forms a more reliable locking force to ensure the stringent stability requirements of the bonding process.

[0049] In summary, this invention innovatively integrates three ring array voice coil motors 131, an air-floating spherical leveling seat 120, and three high-precision laser altimeters to construct a closed-loop intelligent leveling system of "precise laser detection + unconstrained air-floating attitude + high-speed active correction by voice coil motors 131". This system breaks through the technical limitations of traditional passive leveling and open-loop control, achieving fully automatic, high-precision, and dynamic real-time closed-loop leveling, and filling the technical gap in active intelligent leveling of high-end TCB bonding heads 140.

[0050] It should be noted that the present invention also provides a bonding method based on the above-mentioned air flotation leveling device, the bonding method comprising the following steps: S10. Switch the connecting seat 110 and the leveling seat 120 to the leveling state to construct an unconstrained leveling working condition.

[0051] Specifically, after the air-float leveling device receives the leveling command, it moves the bonding head 140 to a preset safe position above the substrate. Then, it injects compressed air into the space between the groove surface of the spherical groove 111 and the convex spherical surface 121 through the air hole, so that an air film is formed between the groove surface of the spherical groove 111 and the convex spherical surface 121. The air-float support force overcomes the weight of the leveling seat 120, the bonding head 140 and the chip, so that the leveling seat 120 is completely suspended without contact, and the mechanical rigid locking constraint is released. At this time, the bonding head 140 is in a flexible floating state with no friction, no stress and two-dimensional free deflection, providing an interference-free working condition for the accurate detection of the subsequent detection unit and the correction of the adjustment component 130.

[0052] S20. The control system fits the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head 140 based on the height data of each reference point on the end face of the bonding head 140 detected by the detection unit, calculates the compensation displacement required for each reference point on the end face of the bonding head 140, and sends the corresponding adjustment command to each adjustment component 130 respectively.

[0053] S30. Each adjustment component 130 drives the reference point corresponding to the end face of the bonding head 140 to move through the leveling seat 120, so as to actively adjust the height of each reference point corresponding to the end face of the bonding head 140.

[0054] Specifically, the detection unit detects the height data of multiple reference points at different positions on the end face of the bonding head 140 in real time. The control system fits the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head 140 based on the height data fed back by the detection unit, calculates the compensation displacement required for each reference point on the end face of the bonding head 140, and sends corresponding adjustment commands to each adjustment component 130. The driving direction of the adjustment component 130 is consistent with the leveling movement direction of the leveling seat 120, that is, it generates linear motion along the axial direction of the leveling seat 120 (or in a direction perpendicular to the end face of the bonding head 140). The installation point of the adjustment component 130 is connected to the leveling seat 120. The axial thrust and displacement output by the adjustment component 130 are directly transmitted to the corresponding installation point of the leveling seat 120, driving the leveling seat 120 to move up and down along the same axial direction at that installation point. Each adjustment component 130 is independently controlled, and each adjustment component 130 is driven by the leveling seat 120. The reference points corresponding to the end face of the bonding head 140 are moved to actively adjust the height of each reference point on the end face of the bonding head 140, achieving precise point-to-point correction: For reference points that are too high, the corresponding adjustment component 130 is controlled to move the corresponding reference point of the bonding head 140 downward through the leveling seat 120, so that the reference point falls back precisely; for reference points that are too low, the corresponding adjustment component 130 is controlled to move the corresponding reference point of the bonding head 140 upward through the leveling seat 120, so that the reference point achieves precise support compensation. In this way, through the coordinated cooperation of multiple adjustment components 130, the multi-degree-of-freedom attitude correction of the bonding head 140 is achieved, gradually correcting the flatness error and two-dimensional tilt angle error of the end face of the bonding head 140. Through repeated iterative detection and correction, until the flatness of the end face of the bonding head 140 and its parallelism relative to the reference surface both reach the preset high-precision threshold, the active correction and leveling of the bonding head 140 is completed.

[0055] In one embodiment, after performing step S30, the bonding method further includes: S40. Secondary inspection and verification of the flatness and two-dimensional tilt angle parameters of the end face of the bonding head 140 to confirm that the leveling accuracy of the bonding head 140 meets the standard.

[0056] Specifically, after the bonding head 140 is leveled and corrected by adjusting component 130, the height data of reference points at multiple different positions on the end face of the bonding head 140 is detected again by the detection unit. The control system refits the flatness and two-dimensional tilt angle data of the end face of the bonding head 140 based on the height data fed back by the detection unit. The control system compares the flatness and two-dimensional tilt angle with the preset flatness and two-dimensional tilt angle accuracy standards respectively. After confirming that the flatness of the end face of the bonding head 140 and its parallelism relative to the reference surface have reached the preset high-precision threshold, the leveling process is determined to be completed.

[0057] In one embodiment, after performing step S40, the bonding method further includes: S50. Switch the connecting seat 110 and the leveling seat 120 to the locked state so that the connecting seat 110 locks the leveling seat 120 in the current leveling position.

[0058] Specifically, after the leveling accuracy of the bonding head 140 is verified to be up to standard, the control system switches the air path to high-pressure locking mode. The air between the groove surface of the spherical groove 111 and the convex spherical surface 121 is discharged through the air hole. The air film between the groove surface of the spherical groove 111 and the convex spherical surface 121 disappears and the vacuum degree increases. The bottom of the leveling seat 120 is subjected to an upward atmospheric pressure that is greater than the weight of the leveling seat 120 itself and the weight of the bonding head 140. This pushes the convex spherical surface 121 of the leveling seat 120 to move toward the spherical groove 111 in the leveled position and press it against the groove surface of the spherical groove 111. This completes the attitude locking of the connecting seat 110 and the leveling seat 120. After locking, the entire leveling seat 120 is free from shaking, offset, and angular drift, completely isolating the interference of high-frequency vibration, hot pressure impact, and high-temperature deformation of the equipment. This ensures that the attitude, flatness, and pressure uniformity of the bonding head 140 remain constant throughout the subsequent hot pressure bonding process.

[0059] In one embodiment, before performing step S10, the bonding method further includes: S02. System power-on initialization and self-test.

[0060] Specifically, after the air flotation leveling device is turned on, the initialization program is started simultaneously. The control system sequentially completes the self-test of the working conditions and zero-point calibration of the air circuit system, multiple detection components 150, and multiple adjustment components 130. At this time, the connecting seat 110 and the leveling seat 120 are locked, the convex spherical surface 121 and the groove surface of the spherical groove 111 are rigidly attached, the posture of the bonding head 140 is fixed, and it waits for the bonding operation command.

[0061] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0062] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. An air flotation leveling device, characterized in that, include: Connector; A leveling seat is used to install a bonding head. The leveling seat is disposed on the connecting seat. The leveling seat has multiple spaced mounting points in its circumference. Each of the multiple mounting points of the leveling seat corresponds one-to-one with a reference point at a different position on the end face of the bonding head. The adjustment components consist of three parts, each disposed at an installation point on the leveling base, and each adjustment component is independently controlled. The connecting seat and the leveling seat have a leveling state and a locked state; in the leveling state, an air film is formed between the connecting seat and the leveling seat, surrounding the periphery of the leveling seat, so that each of the adjustment components can drive the reference point corresponding to the end face of the bonding head to adaptively rise and fall through the leveling seat; in the locked state, the connecting seat locks the leveling seat in the current position. The adjustment assembly includes a voice coil motor and a transmission component. The stator of the voice coil motor is connected to the connecting base via a bracket. The output end of the mover of the voice coil motor is connected to the input end of the transmission component. The output end of the transmission component is connected to the corresponding mounting point on the leveling base. The driving direction of the voice coil motor is consistent with the leveling movement direction of the leveling base. The air flotation leveling device also includes a detection unit, which includes three detection elements. The three detection elements are used to collect the reference point height data of three different positions on the end face of the bonding head in real time. The three adjustment components are arranged in a 120° equally spaced ring along the circumference of the leveling seat, and the three detection elements are arranged in a 120° equally spaced ring along the circumference of the connecting seat. The three detection elements correspond one-to-one with the three adjustment components.

2. The air flotation leveling device according to claim 1, characterized in that, The bottom of the connecting seat is provided with a spherical groove, and multiple air holes are spaced apart on the groove surface; the top of the leveling seat has a convex spherical surface, which is inserted into the spherical groove; the bottom of the leveling seat is connected to a key head. In the leveling state, an air film is formed between the groove surface of the spherical groove and the convex spherical surface. In the locked state, the convex spherical surface can be tightly attached to the groove surface of the spherical groove.

3. The air flotation leveling device according to claim 1, characterized in that, The air flotation leveling device also includes a guide assembly, and the output end of the transmission component is connected to the leveling seat through the guide assembly.

4. The air flotation leveling device according to claim 1, characterized in that, A tension spring assembly is provided between the leveling seat and the connecting seat.

5. A bonding method based on the air flotation leveling device according to any one of claims 1 to 4, characterized in that, The bonding method includes the following steps: S10. Switch the connecting seat and the leveling seat to the leveling state to construct an unconstrained leveling working condition; S20. The control system fits the flatness error and two-dimensional tilt angle error parameters of the end face of the bonding head according to the height data of each reference point on the end face of the bonding head detected by the detection unit, calculates the compensation displacement required for each reference point on the end face of the bonding head, and sends corresponding adjustment commands to each of the adjustment components respectively. S30. Each of the adjustment components drives the reference point corresponding to the end face of the bonding head to move through the leveling seat, so as to actively adjust the height of each reference point corresponding to the end face of the bonding head.

6. The bonding method according to claim 5, characterized in that, The bonding method further includes: S50. Switch the connecting seat and the leveling seat to the locked state so that the connecting seat locks the leveling seat in the current leveling position.

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