Chip thermocompression welding machine for controlling pressing stroke based on dual pressure and control method

Abstract

The invention relates to the technical field of microelectronic packaging and surface mounting, in particular to a chip thermocompression welding machine based on double-pressure control of a pressing stroke and a control method. The chip thermocompression welding machine comprises a lifting frame, a hollow shaft, a vacuum suction nozzle, a lifting driving mechanism, a small-range pressure sensor and a large-range pressure sensor, wherein the hollow shaft is arranged on the lifting frame in a sliding mode and can move in the axial direction of the lifting frame; the vacuum suction nozzle is arranged at the lower end of the hollow shaft; the lifting driving mechanism is connected with the lifting frame; the hollow shaft is connected with an elastic element and an acting block; the elastic element acts on the small-range pressure sensor, in the process that the lifting driving mechanism drives the lifting frame to descend, the vacuum suction nozzle drives the hollow shaft to ascend by a preset stroke relative to the lifting frame under the upward counter-acting force of a chip pressed by the vacuum suction nozzle, and then the acting block abuts against the large-range pressure sensor. According to the invention, the pressing stroke can be adaptively controlled according to the detected pressure, so that the pressure applied to the chip by the vacuum suction nozzle in the chip suction and chip welding process can be accurately controlled.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microelectronic packaging and surface mounting technology, and particularly relates to a chip hot press bonding machine based on double-pressure control and a control method. BACKGROUND

[0002] The chip hot press bonding machine is a key device in the process of semiconductor packaging and micro-assembly, which precisely mounts and bonds the chip to the substrate or lead frame through the hot press bonding process. Its working process mainly includes two core steps: chip suction process and chip welding process. In the chip suction process, the vacuum nozzle of the device is lowered above the chip, and the chip is picked up by applying negative pressure. In the chip welding process, the vacuum nozzle carrying the chip moves above the target position of the substrate, moves downward and applies a specific welding pressure to the chip, while assisting with heating, to complete the electrical connection and mechanical fixation of the chip and the substrate.

[0003] In the above two processes, the pressure applied to the chip by the vacuum nozzle is crucial. In the suction process, moderate suction pressure is needed to ensure reliable pickup without damaging the back of the chip; in the welding process, accurate and stable welding pressure is needed to ensure the quality and consistency of the bonding interface, and too little pressure may cause false welding, and too much pressure may crush the chip or damage the internal circuit.

[0004] Currently, the control strategy commonly used in the industry is to preset a target height for the descent, and when the lifting frame moves the nozzle to this height, it is considered that the pressure applied to the chip has reached the preset value.

[0005] However, this position / travel-based control method has the following inherent defects: (1) Poor pressure control accuracy and low linearity: due to the thickness tolerance, flatness error of the chip and substrate, and the flatness fluctuation of the workbench, the "zero point" of the contact between the nozzle and the chip / substrate is a variable in actual operation. In this case, the actual pressure value corresponding to the fixed downstroke will fluctuate greatly. More importantly, factors such as the stiffness of the mechanical system and the transmission clearance cause the downstroke and the generated pressure not to be in an ideal linear relationship, especially in the micron-level height change range, which will cause an unavoidable pressure difference, making it difficult to meet the process requirements of high-precision welding. Moreover, when replacing the chip and substrate specifications, the target height needs to be re-determined; (2) Unable to adapt to the buffer mechanism, leading to loss of control of pressure: In order to prevent the vacuum nozzle from damaging the fragile chip due to impact when it contacts the chip, the hot bar bonder is usually equipped with a resilient buffer mechanism. This buffer mechanism will be compressed after the vacuum nozzle contacts the chip, and it is a variable stroke itself. In this case, the downstroke of the lifting frame is actually decomposed into the compression amount of the buffer mechanism and the actual displacement acting on the chip. Due to the existence of the force-displacement characteristics of the buffer mechanism, the total stroke of the lifting frame monitored by the system loses the direct and certain correspondence with the real pressure acting on the chip.

[0006] Therefore, it becomes extremely unreliable to control the pressure by presetting the stroke, and the actual applied pressure may be much higher or lower than the preset value, seriously affecting the process consistency and product yield, and the problems existing in the traditional chip hot bar bonding during chip suction and chip bonding need to be solved. SUMMARY

[0007] The technical problem to be solved by the present application is to overcome the defects of the prior art and provide a chip hot bar bonder based on double-pressure control downstroke, which can adaptively control the downstroke according to the detected pressure, thereby accurately controlling the pressure applied to the chip by the vacuum nozzle during the chip suction and chip bonding process.

[0008] In order to solve the above technical problems, the technical scheme of the present application is as follows: A chip hot bar bonder based on double-pressure control downstroke, comprising a lifting frame, a hollow shaft slidably installed on the lifting frame in the axial direction, a vacuum nozzle installed at the lower end of the hollow shaft, and a lifting drive mechanism connected to the lifting frame to drive the lifting frame to lift; The chip hot bar bonder based on double-pressure control downstroke further comprises a small-range pressure sensor and a large-range pressure sensor fixed in height relative to the lifting frame respectively, and the hollow shaft is connected with an elastic element and an action block; wherein, The elastic element acts on the small-range pressure sensor, and during the process of the lifting drive mechanism driving the lifting frame to descend, the vacuum nozzle drives the hollow shaft to ascend a preset stroke relative to the lifting frame under the upward reaction force of the chip it presses, and the action block abuts against the large-range pressure sensor; The small pressure signal detected by the small-range pressure sensor is used to control the downstroke of the lifting frame during the process of the vacuum nozzle suctioning the chip; The large pressure signal detected by the large-range pressure sensor is used to control the downstroke of the lifting frame during the process of the chip suctioned by the vacuum nozzle being hot bar bonded on the substrate.

[0009] Further, in order to rotate the sucked chip to a proper angle, the chip thermal compression bonding machine based on double pressure control down stroke further comprises a rotating driving mechanism, the rotating driving mechanism is installed on the lifting frame, the elastic element is an elastic coupling, and the output shaft of the rotating driving mechanism is connected with the small range pressure sensor and then connected with the upper end of the hollow shaft through the elastic coupling.

[0010] Further, a specific structure of the elastic coupling is provided, which realizes precise axial buffering while torque transmission and deviation compensation. The first slit section has a plurality of first slits which are arranged at intervals along the axial direction and are staggered and opposite in the first direction. The second slit section has a plurality of second slits which are arranged at intervals along the axial direction and are staggered and opposite in the second direction. The circumferential angles of the first slits and the second slits are both greater than 90 degrees.

[0011] Further, in order to reduce the friction of the hollow shaft during rotation and up-down movement, improve the pressure accuracy and position accuracy, a gas bearing is arranged between the hollow shaft and the lifting frame.

[0012] Further, in order to improve the angle accuracy of the hollow shaft and enable internal threading, the rotating driving mechanism is a hollow motor.

[0013] Further, a specific structure of the vacuum suction nozzle is provided, which can automatically replace the end suction nozzle piece, ensure the parallelism of the suction surface, improve the efficiency of thermal compression bonding, and reduce the cost of the suction nozzle. The connecting rod is provided with a chip suction channel and a suction nozzle piece suction channel, the hollow shaft is provided with a first channel and a second channel, the chip suction channel communicates with the first channel, and the suction nozzle piece suction channel communicates with the second channel. The suction nozzle piece fixing block is installed on the connecting rod, is provided with a ventilation channel communicating with the chip suction channel, and is provided with a suction slot surrounding the ventilation channel and communicating with the suction nozzle piece suction channel on the suction nozzle piece abutting surface. The suction nozzle piece is suctioned to the suction nozzle piece abutting surface by the suction slot after the suction nozzle piece suction channel is vacuumized, and a vacuum channel of the suction nozzle piece communicates with the ventilation channel. The heating component is used for heating the suction nozzle piece fixing block.

[0014] Further, another specific structure of the vacuum suction nozzle is provided, which comprises: The connecting rod is provided with a chip suction channel communicating with the hollow shaft. The suction part is connected with the connecting rod, and a vacuumizing channel of the suction part communicates with the chip suction channel. The heating component is used for heating the suction part.

[0015] Further, in order to facilitate the connection of the vacuum suction nozzle and the hollow shaft and better dissipate heat, the vacuum suction nozzle further comprises a connecting sleeve, which is assembled above the heating component, and the vacuum suction nozzle is connected to the hollow shaft through the connecting sleeve, and the connecting sleeve is provided with a plurality of heat dissipation holes.

[0016] Further, in order to make the lifting frame lift more stably and avoid the lifting frame from falling due to power failure, the chip thermal compression bonding machine based on double-pressure control of the downward stroke further comprises a fixing frame, the lifting driving mechanism is installed on the fixing frame, and the lifting frame is slidably installed on the fixing frame, and at least two tension springs are arranged between the fixing frame and the lifting frame.

[0017] Further, the large-range pressure sensor is installed on a mounting body, and a leveling mechanism for adjusting the parallelism of the large-range pressure sensor is arranged between the mounting body and the large-range pressure sensor.

[0018] The application also relates to a control method of a chip thermal compression bonding machine based on double-pressure control of the downward stroke, comprising the following steps: In the process that the lifting driving mechanism drives the lifting frame to descend to adsorb the chip, a small pressure signal detected by the small-range pressure sensor is acquired, and when the pressure value corresponding to the small pressure signal reaches a preset first pressure value, the lifting driving mechanism is controlled to stop driving the lifting frame to descend. In the process that the lifting driving mechanism drives the lifting frame to descend to thermally compress and bond the chip adsorbed by the vacuum suction nozzle on the substrate, a large pressure signal detected by the large-range pressure sensor is acquired, and when the pressure value corresponding to the large pressure signal reaches a preset second pressure value, the lifting driving mechanism is controlled to stop driving the lifting frame to descend; the second pressure value is greater than the first pressure value.

[0019] After the above technical scheme is adopted, the application has the following beneficial effects: 1. In the chip adsorption process and the chip thermal compression bonding process, the pressure transmitted by the hollow shaft to the pressure sensor is detected, and the lifting frame is controlled to stop descending when the pressure reaches the respective preset value. That is, the downward stroke of the lifting frame is adaptively controlled according to the detected pressure, is not affected by the thickness difference of the chip and the substrate itself and the buffer deformation of the elastic mechanism, and can accurately control the pressure applied to the chip by the vacuum suction nozzle in the chip adsorption process and the chip thermal compression bonding process, so as to provide moderate adsorption pressure in the chip adsorption process to ensure reliable pickup without damaging the back of the chip, and provide accurate and stable bonding pressure in the chip thermal compression bonding process to ensure the quality and consistency of the bonding interface; also accurately realize small pressure adsorption of the chip and large pressure mounting, avoid damage to the chip, and ensure the mounting effect. 2、The present application is based on the pressure control of the lower stroke of the lifting frame, and small and large range pressure sensors are arranged at the same time, small pressure is measured by flexibility, and large pressure is measured by rigidity, the small and large range pressure sensors are used in steps through ingenious structure design, the pressure measurement in the chip suction process and the chip hot pressure welding process is realized respectively, the small range pressure sensor is not overloaded and damaged due to the large pressure in the welding process, the measurement range and precision are achieved, so that the lower pressure range of the lifting frame in the chip suction process and the chip hot pressure welding process can be controlled more accurately, and accurate and stable welding pressure can be provided in the two processes. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is a structural schematic view of the chip hot pressure welding machine based on the double-pressure control lower stroke of the present application. Figure 2 It is a sectional view of Figure 1 . Figure 3 It is an enlarged view of A part of Figure 2 . Figure 4 It is a structural schematic view of the elastic coupling of the present application. Figure 5 It is a front view of Figure 4 . Figure 6 It is a top view of Figure 4 . Figure 7 It is an A-A sectional view of Figure 6 . Figure 8 It is an enlarged view of B part of Figure 2 . Figure 9 It is a structural schematic view of the suction nozzle piece of the first vacuum suction nozzle of the present application. Figure 10 It is a structural schematic view of another view angle of the suction nozzle piece of the first vacuum suction nozzle of the present application. Figure 11 It is a structural schematic view of the suction nozzle piece fixing block of the first vacuum suction nozzle of the present application. Figure 12 It is a structural schematic view of the second vacuum suction nozzle of the present application. In the figure: 1, lifting frame; 2, hollow shaft; 201, first channel; 202, second channel; 3. Vacuum nozzle; 301. Connecting rod; 3011. Chip adsorption channel; 3012. Nozzle plate adsorption channel; 302. Nozzle plate fixing block; 3020. Nozzle plate mating surface; 3021. Ventilation channel; 3022. Suction groove; 3023. Positioning pin; 3024. Bolt hole; 303. Nozzle plate; 3031. Vacuum channel; 3032. Positioning hole; 304. Heating component; 305. Adsorption part; 3051. Vacuuming channel; 306. Connecting sleeve; 3061. Heat dissipation hole; 307. Heat insulation plate; 4. Lifting drive mechanism; 5. Small-range pressure sensor; 6. Large-range pressure sensor; 7. Elastic element; 701. First slit segment; 7011. First slit; 702. Second slit segment; 7021. Second slit; 703. Connecting end; 7031. Radial groove; 7032. Clamping part; 70321. Through hole; 8. Action block; 9. Rotary drive mechanism; 10. Air bearing; 11. Fixture; 12. Tension spring; 13. First electric slip ring; 14. Second electric slip ring; 15. Leveling mechanism. Detailed Implementation

[0021] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0022] Example 1: As Figures 1 to 11 As shown, a chip hot press welding machine based on dual pressure control pressing stroke includes a lifting frame 1, a hollow shaft 2 that can be slidably installed on the lifting frame 1 along its axial direction, a vacuum nozzle 3 installed at the lower end of the hollow shaft 2, and a lifting drive mechanism 4 connected to the lifting frame 1 to drive the lifting frame 1 to lift. The chip hot-press welding machine based on dual-pressure control of the pressing stroke also includes a small-range pressure sensor 5 and a large-range pressure sensor 6, which are respectively fixed at a height relative to the lifting frame 1. The hollow shaft 2 is connected to an elastic element 7 and an actuating block 8. The elastic element 7 acts on the small-range pressure sensor 5. During the process of the lifting drive mechanism 4 driving the lifting frame 1 to descend, the vacuum nozzle 3 drives the hollow shaft 2 to rise relative to the lifting frame 1 by the upward reaction force of the chip it presses. After a preset stroke, the action block 8 abuts against the large-range pressure sensor 6. The small pressure signal detected by the small range pressure sensor 5 is used to control the descending stroke of the lifting frame 1 during the process of the vacuum suction nozzle 3 sucking the chip; The large pressure signal detected by the large range pressure sensor 6 is used to control the descending stroke of the lifting frame 1 during the process of the chip sucked by the vacuum suction nozzle 3 being thermocompression bonded on the substrate.

[0023] Wherein, before the vacuum suction nozzle 3 contacts the chip and at the initial stage of contacting the chip, there is a gap between the acting block 8 and the large range pressure sensor 6, and the gap gradually decreases as the hollow shaft 2 is lifted relative to the lifting frame 1 under the upward reaction force of the chip pressed by the vacuum suction nozzle 3, and the gap becomes zero (in the state of Figure 2 and Figure 3 the acting block 8 abuts against the large range pressure sensor 6, and the large range pressure sensor 6 can detect the large pressure signal.

[0024] It should be noted that, no matter the chip sucking process or the chip bonding process, the vacuum suction nozzle 3 applies downward pressure to the chip, and the small pressure signal can be detected by the small range pressure sensor 5. During the chip sucking process, the pressure applied to the chip by the vacuum suction nozzle 3 is relatively small, and the pressure applied to the chip by the vacuum suction nozzle 3 can meet the requirements before the acting block 8 is lifted relative to the lifting frame 1 to abut against the large range pressure sensor 6. Therefore, the small pressure signal detected by the small range pressure sensor 5 is used to control the descending stroke of the lifting frame 1 during the process of the vacuum suction nozzle 3 sucking the chip. During the chip bonding process, the pressure applied to the chip by the vacuum suction nozzle 3 is relatively large, and the pressure applied to the chip by the vacuum suction nozzle 3 can meet the requirements after the acting block 8 abuts against the large range pressure sensor 6. Therefore, the large pressure signal detected by the large range pressure sensor 6 is used to control the descending stroke of the lifting frame 1 during the process of the chip sucked by the vacuum suction nozzle 3 being thermocompression bonded on the substrate.

[0025] Specifically, the chip sucking process and the chip thermocompression bonding process are detected in the embodiment, and the pressure transmitted to the pressure sensor by the hollow shaft 2 is detected, and the lifting frame 1 is controlled to stop descending when the pressure reaches a preset value. That is, the descending stroke of the lifting frame 1 is adaptively controlled according to the detected pressure, and is not affected by the thickness difference of the chip and the substrate itself and the buffer deformation of the elastic mechanism, so that the pressure applied to the chip by the vacuum suction nozzle 3 during the chip sucking process and the chip thermocompression bonding process can be accurately controlled by adaptively controlling the descending stroke of the lifting frame 1, thereby providing moderate sucking pressure during the chip sucking process to ensure reliable pickup without damaging the back of the chip, and providing accurate and stable bonding pressure during the chip thermocompression bonding process to ensure the quality and consistency of the bonding interface; and small pressure sucking of the chip and large pressure mounting are accurately realized to avoid damage to the chip and ensure the mounting effect.

[0026] Furthermore, the pressure applied to the chip by the vacuum nozzle 3 during chip pick-up is relatively low, while the pressure applied during thermocompression welding is much higher, resulting in a significant pressure difference between the two processes. If a small-range pressure sensor is used to monitor the pressure in both processes, it operates within its optimal range during chip pick-up, offering high resolution and accurate feedback. However, during thermocompression welding, this can lead to overload, damage, or the sensor consistently outputting its maximum value. Conversely, using a large-range pressure sensor can cover the high pressure required for thermocompression welding without overload. However, during chip pick-up, the actual pressure represents a relatively small proportion of the large-range sensor's full-scale range, leading to higher resolution and relative error, resulting in inaccurate control and potentially pick-up failure or chip damage.

[0027] In this embodiment, based on the downward stroke of the pressure-controlled lifting frame 1, a small-range pressure sensor 5 and a large-range pressure sensor 6 are simultaneously set. The small pressure is measured using flexible measurement, while the large pressure is measured using rigid measurement. Through ingenious structural design, the small-range pressure sensor 5 and the large-range pressure sensor 6 are used in a stepped manner to realize pressure measurement during the chip pick-up process and the chip hot-pressing welding process, respectively. The small-range pressure sensor 5 will not be overloaded or damaged due to the large pressure during the welding process, thus achieving "both measurement range and accuracy". This allows for more precise control of the downward stroke of the lifting frame during the chip pick-up process and the chip welding process, thereby providing more accurate and stable welding pressure in both processes.

[0028] In this embodiment, the maximum range of the small-range pressure sensor 5 can be 2 kg, and the maximum range of the large-range pressure sensor 6 can be 50 kg, but it is not limited to this and can be configured to other values ​​as needed.

[0029] In this embodiment, the lifting drive mechanism 4 may be a robotic arm or a linear module, etc.

[0030] In this embodiment, preferably, the small-range pressure sensor 5, the large-range pressure sensor 6, and the lifting drive mechanism 4 are respectively connected to the controller. Based on the pressure signal fed back by the small-range pressure sensor 5, the controller controls the descent stroke of the lifting frame 1 during the process of the lifting drive mechanism 4 driving the lifting frame 1 to descend so that the vacuum nozzle 3 can pick up the chip; based on the pressure signal detected by the large-range pressure sensor 6, the controller controls the descent stroke of the lifting frame 1 during the process of the lifting drive mechanism 4 driving the lifting frame 1 to descend so that the chip picked up by the vacuum nozzle 3 can be thermo-pressed onto the substrate.

[0031] In this embodiment, as Figure 2 , Figures 8 to 11 As shown, the vacuum nozzle 3 includes: The connecting rod 301 is provided with a chip suction channel 3011 and a suction nozzle piece suction channel 3012, the hollow shaft 2 is provided with a first channel 201 and a second channel 202, the chip suction channel 3011 is communicated with the first channel 201, and the suction nozzle piece suction channel 3012 is communicated with the second channel 202; The suction nozzle piece fixing block 302 is installed on the connecting rod 301, which is provided with a ventilation channel 3021 communicated with the chip suction channel 3011, and a suction slot 3022 communicated with the suction nozzle piece suction channel 3012 and surrounding the ventilation channel 3021 is arranged on the suction nozzle piece abutting surface 3020 thereof; The suction nozzle piece 303 is suctioned to abut against the suction nozzle piece abutting surface 3020 by the suction slot 3022 after the suction nozzle piece suction channel 3012 is vacuumized, and a vacuum channel 3031 thereof is communicated with the ventilation channel 3021; The heating component 304 is used for heating the suction nozzle piece fixing block 302, which can be but is not limited to a heating plate abutting against an end surface of the suction nozzle piece fixing block 302 away from the suction nozzle piece abutting surface 3020; The connecting sleeve 306 is fitted above the heating component 304, the vacuum suction nozzle 3 is connected with the hollow shaft 2 through the connecting sleeve 306 thereof, and the connecting sleeve 306 is provided with a plurality of heat dissipation holes 3061.

[0032] The suction nozzle piece suction channel 3012 and the suction slot 3022 jointly form an air path for suctioning the suction nozzle piece 303, and the chip suction channel 3011, the ventilation channel 3021 and the vacuum channel 3031 of the suction nozzle piece 303 jointly form an air path for suctioning the chip.

[0033] The vacuum suction nozzle 3 in the embodiment can heat the suction nozzle piece fixing block 302 through the heating component 304, heat the suction nozzle piece 303, and thus accurately transfer heat to the chip and the substrate on which the chip is mounted through the suction nozzle piece 303, so as to realize hot pressing and mount, and avoid the trouble of an external substrate heating mechanism.

[0034] Moreover, when different specifications of chip products are replaced, the vacuum of the suction slot 3022 is broken through the suction nozzle piece suction channel 3012, so that the originally suctioned suction nozzle piece 303 is automatically separated from the suction nozzle piece abutting surface 3020 of the suction nozzle piece fixing block 302 under the action of gravity; then the suction nozzle piece suction channel 3012 is vacuumized, so that the suction nozzle piece abutting surface 3020 automatically suction the new suction nozzle piece 303, so as to realize automatic replacement of the suction nozzle piece 303. Compared with manual disassembly and replacement, the replacement efficiency is higher, and the trouble of frequent shutdown of the chip hot pressing and welding machine is also avoided.

[0035] In addition, since the nozzle sheet 303 is attached to the nozzle sheet fixing block 302 by surface-to-surface attachment, the parallelism of the newly replaced nozzle sheet 303 can be ensured, and the adjustment and calibration of the nozzle sheet 303 can be avoided, thereby ensuring the stability of the quality of the attachment of the nozzle sheet 303 to the chip of various specifications and facilitating the accurate pressure detection of the small-range pressure sensor 5 and the large-range pressure sensor 6.

[0036] In addition, since the nozzle sheet 303 is attached to the nozzle sheet fixing block 302 by surface-to-surface attachment, the parallelism of the newly replaced nozzle sheet 303 can be ensured, and the adjustment and calibration of the nozzle sheet 303 can be avoided, thereby ensuring the stability of the quality of the attachment of the nozzle sheet 303 to the chip of various specifications and facilitating the accurate pressure detection of the small-range pressure sensor 5 and the large-range pressure sensor 6.

[0037] In addition, since the nozzle sheet 303 is attached to the nozzle sheet fixing block 302 by surface-to-surface attachment, the parallelism of the newly replaced nozzle sheet 303 can be ensured, and the adjustment and calibration of the nozzle sheet 303 can be avoided, thereby ensuring the stability of the quality of the attachment of the nozzle sheet 303 to the chip of various specifications and facilitating the accurate pressure detection of the small-range pressure sensor 5 and the large-range pressure sensor 6.

[0038] In the embodiment, the mounting of the nozzle sheet fixing block 302 and the connecting rod 301 can be achieved in various ways. For example, as shown in Figs. 3 and 4, a portion of the nozzle sheet fixing block 302 is sleeved on the connecting rod 301, and at least one bolt hole 3024 is arranged on the nozzle sheet fixing block 302. A locking bolt is screwed into the bolt hole 3024 and abuts against the outer peripheral wall of the connecting rod 301, so that the mounting of the nozzle sheet fixing block 302 and the connecting rod 301 is achieved. Preferably, two bolt holes 3024 are arranged on the nozzle sheet fixing block 302 and are opposite to each other in the radial direction of the connecting rod 301. In this way, the connecting rod 301 can be centered in the nozzle sheet fixing block 302, and the balance of the weight of the entire vacuum nozzle 3 on both sides can be better achieved. The nozzle sheet fixing block 302 and the connecting rod 301 can also be connected by threads. Figure 2 、 Figure 8 and Figure 11 In the embodiment, as shown in Figs. 3 and 4, a portion of the nozzle sheet fixing block 302 is sleeved on the connecting rod 301, and at least one bolt hole 3024 is arranged on the nozzle sheet fixing block 302. A locking bolt is screwed into the bolt hole 3024 and abuts against the outer peripheral wall of the connecting rod 301, so that the mounting of the nozzle sheet fixing block 302 and the connecting rod 301 is achieved. Preferably, two bolt holes 3024 are arranged on the nozzle sheet fixing block 302 and are opposite to each other in the radial direction of the connecting rod 301. In this way, the connecting rod 301 can be centered in the nozzle sheet fixing block 302, and the balance of the weight of the entire vacuum nozzle 3 on both sides can be better achieved. The nozzle sheet fixing block 302 and the connecting rod 301 can also be connected by threads.

[0039] In the embodiment, as shown in Figs. 3 and 4, a portion of the nozzle sheet fixing block 302 is sleeved on the connecting rod 301, and at least one bolt hole 3024 is arranged on the nozzle sheet fixing block 302. A locking bolt is screwed into the bolt hole 3024 and abuts against the outer peripheral wall of the connecting rod 301, so that the mounting of the nozzle sheet fixing block 302 and the connecting rod 301 is achieved. Preferably, two bolt holes 3024 are arranged on the nozzle sheet fixing block 302 and are opposite to each other in the radial direction of the connecting rod 301. In this way, the connecting rod 301 can be centered in the nozzle sheet fixing block 302, and the balance of the weight of the entire vacuum nozzle 3 on both sides can be better achieved. The nozzle sheet fixing block 302 and the connecting rod 301 can also be connected by threads. Figure 2 、 Figure 8 and Figure 11 In the embodiment, as shown in Figs. 3 and 4, a portion of the nozzle sheet fixing block 302 is sleeved on the connecting rod 301, and at least one bolt hole 3024 is arranged on the nozzle sheet fixing block 302. A locking bolt is screwed into the bolt hole 3024 and abuts against the outer peripheral wall of the connecting rod 301, so that the mounting of the nozzle sheet fixing block 302 and the connecting rod 301 is achieved. Preferably, two bolt holes 3024 are arranged on the nozzle sheet fixing block 302 and are opposite to each other in the radial direction of the connecting rod 301. In this way, the connecting rod 301 can be centered in the nozzle sheet fixing block 302, and the balance of the weight of the entire vacuum nozzle 3 on both sides can be better achieved. The nozzle sheet fixing block 302 and the connecting rod 301 can also be connected by threads.

[0040] In the embodiment, preferably, as shown in Figure 9 and Figure 11 The nozzle sheet fixing block 302 is provided with at least two positioning pins 3023, and the nozzle sheet 303 is provided with positioning holes 3032 matched with the positioning pins 3023. In this way, the nozzle sheet 303 can be positioned by the cooperation of the positioning pins 3023 and the positioning holes 3032 during the automatic suction of the nozzle sheet 303, so that the nozzle sheet 303 is suctioned at the expected position of the nozzle sheet fitting surface 3020. Among them, the two positioning pins 3023 can be located on one diagonal line of the nozzle sheet fitting surface 3020 of the nozzle sheet fixing block 302.

[0041] In addition, considering that the alignment of the nozzle sheet fitting surface 3020 and the nozzle sheet 303 is realized by the automatic positioning of the camera of the chip thermal compression bonding machine during the automatic suction of the nozzle sheet 303 by the vacuum nozzle 3, in order to enable the chip thermal compression bonding machine to better position the nozzle sheet fitting surface 3020 and the nozzle sheet 303 and better realize the alignment of the nozzle sheet fitting surface 3020 and the nozzle sheet 303, the nozzle sheet fixing block 302 and the nozzle sheet 303 are respectively provided with identification holes for the camera to identify, and the identification holes on the nozzle sheet fixing block 302 and the nozzle sheet 303 can be aligned with each other.

[0042] In the embodiment, preferably, as shown in Figure 8 The openings of the chip suction channel 3011 and the nozzle sheet suction channel 3012 away from the nozzle sheet fixing block 302 are respectively located on the end face and the peripheral wall of the connecting rod 301.

[0043] In this way, the components of the chip thermal compression bonding machine respectively communicating with the chip suction channel 3011 and the nozzle sheet suction channel 3012 can be more conveniently arranged. In addition, the first channel 201 of the hollow shaft 2 can be centered, and the second channels 202 can be arranged around the first channel 201, and the openings of the second channels 202 close to the vacuum nozzle 3 can also be formed on the peripheral wall.

[0044] Connecting the connecting sleeve 306 to the chip thermal compression bonding machine realizes the installation of the entire vacuum nozzle 3 on the chip thermal compression bonding machine, and the connecting sleeve 306 provides convenience for the installation of the vacuum nozzle 3 on the chip thermal compression bonding machine. The connecting sleeve 306 is provided with a plurality of heat dissipation holes 3061, so that heat dissipation can be better, and the heat transferred from the heating component 304 to the chip thermal compression bonding machine can be reduced. In order to better reduce the heat transferred from the heating component 304 to the chip thermal compression bonding machine, the vacuum nozzle 3 further comprises a heat insulation plate 307 installed in the connecting sleeve 306 and located on the side of the heating component 304 away from the nozzle sheet fixing block 302.

[0045] In the embodiment, as shown in Figure 1 and Figure 2As shown, the chip thermal compression bonding machine based on double pressure control downstroke further comprises a fixed frame 11, the lifting driving mechanism 4 is installed on the fixed frame 11, the lifting frame 1 is slidably installed on the fixed frame 11, and at least two tension springs 12 are arranged between the fixed frame 11 and the lifting frame 1.

[0046] Specifically, part of the weight of the moving part is offset by the tension spring 12, so that the moving part will not fall downward due to the weight in the power-off state.

[0047] Embodiment two: the main difference between this embodiment and embodiment one is that the structure of the vacuum nozzle 3 used is different. As shown in Figure 12 The nozzle piece fixing block 302 and the nozzle piece 303 of the vacuum nozzle 3 in embodiment one are replaced by an integrally formed adsorption part 305, the connecting rod 301 only has a chip adsorption channel 3011, the entire hollow shaft 2 only has a first channel 201 communicating with the chip adsorption channel 3011, the hollow cylinder of the adsorption part 305 is threadedly connected with the connecting rod 301 through the heating part 304, the vacuumizing channel 3051 of the adsorption part 305 communicates with the chip adsorption channel 3011, and the chip adsorption channel 3011 communicates with the first channel 201 of the hollow shaft 2.

[0048] The vacuum nozzle 3 with such a structure is simple in structure.

[0049] Embodiment three: based on embodiment one or embodiment two, as shown in Figures 1 to 7 The chip thermal compression bonding machine based on double pressure control downstroke further comprises a rotary driving mechanism 9, the rotary driving mechanism 9 is installed on the lifting frame 1, the elastic element 7 is an elastic coupling, the output shaft of the rotary driving mechanism 9 is connected with the small range pressure sensor 5 and then connected with the upper end of the hollow shaft 2 through the elastic coupling.

[0050] The rotary driving mechanism 9 is arranged, so that the angle of the adsorbed chip can be adjusted as needed, and the use flexibility is improved. The torque is transmitted through the elastic coupling, the axial impact of the hollow shaft 2 is absorbed and buffered, the chip is protected, and the pressure can be transmitted to the small range pressure sensor 5.

[0051] Preferably, as shown in Figures 2-7 The elastic coupling comprises a metal sleeve, the metal sleeve is provided with a first slitting section 701 and a second slitting section 702 in the axial direction; wherein, The first slitting section 701 has a plurality of first slits 7011 which are arranged at intervals in the axial direction and are staggered and opposite in the first direction; The second slitting section 702 has a plurality of second slits 7021 which are arranged at intervals in the axial direction and are staggered and opposite in the second direction, and the second direction is perpendicular to the first direction; the first slits 7011 are cut in the first direction, and the second slits 7021 are cut in the second direction.

[0052] The circumferential angles of the first slits 7011 and the second slits 7021 are both greater than 90 degrees, preferably 135 degrees.

[0053] Specifically, the multiple first slits 7011 of the first slit section 701 are staggered and opposite in the first direction, and the multiple second slits 7021 of the second slit section 702 are staggered and opposite in the second direction perpendicular to the first direction. Through the cooperation of the first slit section 701 and the second slit section 702, while torque transmission and deviation compensation are achieved, effective axial precise buffering in the first direction and the second direction can be achieved, and there is no closed loop slit, the torsional stiffness is higher, and the torsion can be inhibited. The application of such an elastic coupling to a chip thermal compression bonding machine can reduce the number of parts, not only can simplify the overall structure and reduce the cost, but also can reduce the failure probability caused by additional mechanisms, and improve the equipment integration and reliability.

[0054] For the convenience of description, the first direction is taken as the front-rear direction, and the second direction is taken as the left-right direction.

[0055] The circumferential angle of the first slit 7011 is greater than 90 degrees, so the first slits 7011 distributed on the front and rear sides of the first slit section 701 coincide in the left and right positions of the metal sleeve wall in the axial direction of the metal sleeve. That is, the first slit section 701 has dense slits in the left and right positions and sparse slits in the front and rear positions, which can provide effective axial precise buffering in the left and right positions and provide the rigidity required for torque transmission of the coupling in the front and rear positions.

[0056] The circumferential angle of the second slit 7021 is greater than 90 degrees, so the second slits 7021 distributed on the left and right sides of the second slit section 702 coincide in the front and rear positions of the metal sleeve wall in the axial direction of the metal sleeve. That is, the second slit section 702 has sparse slits in the left and right positions and dense slits in the front and rear positions, which can provide effective axial precise buffering in the front and rear positions and provide the rigidity required for torque transmission of the coupling in the left and right positions.

[0057] In this way, the entire elastic coupling can better perform the dual roles of torque transmission, deviation compensation, and precise axial buffering, and can also enable the small-range pressure sensor 5 to accurately measure the pressure.

[0058] In the case where the circumferential angles of the first slits 7011 and the second slits 7021 are both 135 degrees, the first slits 7011 are sparse in the front and rear 90-degree central angle ranges of the metal sleeve and dense in the left and right 90-degree central angle ranges, while the second slits 7021 are sparse in the left and right 90-degree central angle ranges of the metal sleeve and dense in the front and rear 90-degree central angle ranges. In this way, the entire coupling can achieve axial precise buffering in all directions in the entire circumference while meeting the requirements of rigidity in all directions in the circumference, further improving the performance.

[0059] As shown in FIG. 6, the first slits 7011 and the second slits 7021 are staggered and opposite in the front-rear direction and the left-right direction.Figures 2 to 7 As shown, both ends of the metal sleeve are connecting ends 703, each connecting end 703 is divided into two clamping parts 7032 by a radial slot 7031, and both sides of the two clamping parts 7032 are respectively provided with through holes 70321 for the locking bolts to pass through.

[0060] In use, the small-range pressure sensor 5 and the shaft of the hollow shaft 2 are respectively inserted into the corresponding connecting end 703, then one locking bolt is simultaneously inserted into the through holes 70321 on one side of the two clamping parts 7032, and the locking nut is tightened, and the other locking bolt is simultaneously inserted into the through holes 70321 on the other side of the two clamping parts 7032, and the locking nut is tightened, and the assembly is completed.

[0061] In this embodiment, as shown in Figure 2 and Figure 3 The air floating bearing 10 can also be arranged between the hollow shaft 2 and the lifting frame 1, which reduces the friction when the hollow shaft 2 rotates and moves up and down, and improves the pressure accuracy and position accuracy.

[0062] In this embodiment, the large-range pressure sensor 6 can be fixedly installed on the lifting frame 1, or fixedly installed on the outer ring of the air floating bearing 10, or fixedly installed on the shell installed on the lifting frame 1, and in the structure shown in Figure 2 and Figure 3 The large-range pressure sensor 6 is fixedly installed on the outer ring of the air floating bearing 10.

[0063] In this embodiment, the component carrying the large-range pressure sensor 6 is referred to as the mounting body, and preferably, as shown in Figure 2 and Figure 3 The leveling mechanism 15 is arranged between the mounting body and the large-range pressure sensor 6.

[0064] Specifically, by providing the leveling mechanism 15, the parallelism of the large-range pressure sensor 6 can be adjusted to ensure the parallelism of the large-range pressure sensor 6, and thus the detection of the large pressure signal is accurately realized.

[0065] As shown in Figure 2 and Figure 3 The leveling mechanism 15 can include but is not limited to at least two leveling bolts, all of which are arranged along the circumference of the large-range pressure sensor 6, preferably uniformly distributed, and the leveling bolts are screwed to the mounting body after passing through the large-range pressure sensor 6 from bottom to top, that is, the large-range pressure sensor 6 is installed on the mounting body through the leveling mechanism 15. By adjusting the corresponding leveling bolts, the large-range pressure sensor 6 can be leveled.

[0066] In this embodiment, as shown in Figure 2As shown, the rotary drive mechanism 9 is preferably a hollow motor, so that the wires can be internally threaded, simplifying the structural design. The hollow motor can be, but is not limited to, a hollow stepping motor or a hollow servo motor.

[0067] In this embodiment, considering that the small-range pressure sensor 5 will rotate with the hollow shaft 2, in order to facilitate the lead-out of the wires of the small-range pressure sensor 5, a first electric slip ring 13 for realizing the lead-out of the wires of the small-range pressure sensor 5 is arranged above the closed-loop hollow stepping motor. Considering that the vacuum suction nozzle 3 with the heating component 304 will also rotate with the hollow shaft 2, a second electric slip ring 14 for realizing the lead-out of the wires of the heating component 304 is also arranged above the vacuum suction nozzle 3.

[0068] Embodiment four: a control method of a chip thermal compression bonding machine based on double-pressure control downstroke, as described in any one of embodiments one, two or three, comprising: In the process of driving the lifting frame 1 to descend by the lifting drive mechanism 4 to adsorb the chip, the small pressure signal detected by the small-range pressure sensor 5 is acquired, and when the pressure value corresponding to the small pressure signal reaches the preset first pressure value, the lifting drive mechanism 4 is controlled to stop driving the lifting frame 1 to descend. In the process of driving the lifting frame 1 to descend by the lifting drive mechanism 4 to thermally compression bond the chip sucked by the vacuum suction nozzle 3 on the substrate, the large pressure signal detected by the large-range pressure sensor 6 is acquired, and when the pressure value corresponding to the large pressure signal reaches the preset second pressure value, the lifting drive mechanism 4 is controlled to stop driving the lifting frame 1 to descend; the second pressure value is greater than the first pressure value.

[0069] Based on the above ideal embodiments according to the present application, through the above description, relevant personnel can make various changes and modifications without deviating from the technical idea of the present application. The technical scope of the present application is not limited to the contents of the specification, and must be determined by the scope of the claims.

Claims

1. A chip hot press welding machine based on dual pressure control downward stroke, comprising a lifting frame (1), a hollow shaft (2) slidably mounted on the lifting frame (1) axially, a vacuum nozzle (3) mounted on the lower end of the hollow shaft (2), and a lifting drive mechanism (4) connected to the lifting frame (1) to drive the lifting frame (1) to lift; characterized in that, It also includes a small-range pressure sensor (5) and a large-range pressure sensor (6) fixed at a height relative to the lifting frame (1), and the hollow shaft (2) is connected to an elastic element (7) and an actuating block (8); wherein, The elastic element (7) acts on the small-range pressure sensor (5). During the process of the lifting drive mechanism (4) driving the lifting frame (1) to descend, the vacuum nozzle (3) drives the hollow shaft (2) to rise relative to the lifting frame (1) by the upward reaction force of the chip it presses. After a preset stroke, the action block (8) abuts against the large-range pressure sensor (6). The small pressure signal detected by the small-range pressure sensor (5) is used to control the descent stroke of the lifting frame (1) during the process of the vacuum nozzle (3) picking up the chip; The large pressure signal detected by the large-range pressure sensor (6) is used to control the descent stroke of the lifting frame (1) during the process of hot-pressing the chip sucked by the vacuum nozzle (3) onto the substrate.

2. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 1, characterized in that, It also includes a rotary drive mechanism (9), which is installed on the lifting frame (1). The elastic element (7) is an elastic coupling. The output shaft of the rotary drive mechanism (9) is connected to a small-range pressure sensor (5) and then connected to the upper end of the hollow shaft (2) through the elastic coupling.

3. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 2, characterized in that, The flexible coupling includes a metal sleeve, which has a first slit section (701) and a second slit section (702) arranged axially; wherein, The first slit segment (701) has a plurality of first slits (7011) spaced apart along the axial direction and staggered in a first direction. The second slit segment (702) has a plurality of second slits (7021) that are spaced apart along the axial direction and staggered in a second direction, the second direction being perpendicular to the first direction; The circumferential angles of both the first slit (7011) and the second slit (7021) are greater than 90 degrees.

4. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 2, characterized in that, An air bearing (10) is provided between the hollow shaft (2) and the lifting frame (1).

5. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 2, characterized in that, The rotary drive mechanism (9) is a hollow motor.

6. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 1, characterized in that, The vacuum nozzle (3) includes: The connecting rod (301) is provided with a chip adsorption channel (3011) and a nozzle adsorption channel (3012). The hollow shaft (2) is provided with a first channel (201) and a second channel (202). The chip adsorption channel (3011) is connected to the first channel (201), and the nozzle adsorption channel (3012) is connected to the second channel (202). The nozzle plate fixing block (302) is installed on the connecting rod (301). It is provided with an air passage (3021) that connects to the chip adsorption channel (3011), and a suction groove (3022) that connects to the nozzle plate adsorption channel (3012) and surrounds the air passage (3021) is provided on its nozzle plate mating surface (3020). The suction plate (303) is suctioned to the suction plate bonding surface (3020) by the suction groove (3022) after the suction plate adsorption channel (3012) is evacuated, and its vacuum channel (3031) is connected to the ventilation channel (3021). Heating component (304) is used to heat the nozzle plate fixing block (302).

7. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 1, characterized in that, The vacuum nozzle (3) includes: The connecting rod (301) is provided with a chip adsorption channel (3011) that connects to the hollow shaft (2). The adsorption section (305) is connected to the connecting rod (301), and its vacuum channel (3051) is connected to the chip adsorption channel (3011). Heating component (304) is used to heat adsorption part (305).

8. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 6 or 7, characterized in that, The vacuum nozzle (3) also includes a connecting sleeve (306), which is mounted above the heating component (304). The vacuum nozzle (3) is connected to the hollow shaft (2) through its connecting sleeve (306). The connecting sleeve (306) is provided with multiple heat dissipation holes (3061).

9. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 1, characterized in that, It also includes a fixed frame (11), a lifting drive mechanism (4) mounted on the fixed frame (11), a lifting frame (1) slidably mounted on the fixed frame (11), and at least two tension springs (12) disposed between the fixed frame (11) and the lifting frame (1).

10. The chip hot pressing welding machine based on dual-pressure control of the pressing stroke according to claim 1, characterized in that, A large-range pressure sensor (6) is mounted on a mounting body, and a leveling mechanism (15) for adjusting the parallelism of the large-range pressure sensor (6) is provided between the mounting body and the large-range pressure sensor (6).

11. A control method for a chip thermoforming machine based on dual-pressure control of the pressing stroke as described in any one of claims 1-10, characterized in that, include: During the process of the lifting drive mechanism (4) driving the lifting frame (1) to descend to adsorb the chip, a small pressure signal detected by the small range pressure sensor (5) is obtained. When the pressure value corresponding to the small pressure signal reaches the preset first pressure value, the lifting drive mechanism (4) is controlled to stop driving the lifting frame (1) to descend. During the process of the lifting drive mechanism (4) driving the lifting frame (1) to descend to heat-press the chip sucked by the vacuum nozzle (3) onto the substrate, a large pressure signal detected by the large range pressure sensor (6) is obtained. When the pressure value corresponding to the large pressure signal reaches the preset second pressure value, the lifting drive mechanism (4) is controlled to stop driving the lifting frame (1) to descend; the second pressure value is greater than the first pressure value.

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