Chip thermal compression bonding machine based on double-pressure control and control method of compression stroke

Abstract

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 downstroke and a control method. The chip hot press bonding machine comprises a lifting frame, a hollow shaft slidably installed in the lifting frame along the axial direction, a vacuum suction nozzle installed at the lower end of the hollow shaft, a lifting driving mechanism connected with the lifting frame, and a small range pressure sensor and a large range pressure sensor fixed at a height relative to the lifting frame, and the hollow shaft is connected with an elastic element and an action block; the elastic element acts on the small range pressure sensor, and in the process of driving the lifting frame to move downward by the lifting driving mechanism, the vacuum suction nozzle drives the hollow shaft to ascend a preset stroke under the upward reaction force of the chip pressed by the vacuum suction nozzle, and then the action block abuts against the large range pressure sensor. The present application can adaptively control the downstroke according to the detected pressure, so as to accurately control the pressure applied to the chip by the vacuum suction nozzle in the process of chip suction and chip welding.

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 downstroke and a control method. BACKGROUND

[0002] The chip hot press bonding machine is a key device in the process of semiconductor post-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 adsorption; 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 assisted by 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 small pressure may cause false welding, and too large pressure may easily crush the chip or cause internal circuit damage.

[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:

[0006] (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, the stiffness, transmission clearance and other factors of the mechanical system 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 the chip and substrate specifications are changed, the target height needs to be re-determined;

[0007] (2) Unable to adapt to the buffer mechanism, leading to loss of control of pressure: to prevent the vacuum nozzle in contact with the chip at the moment of impact and damage to fragile chips, hot bar bonder nozzle is usually equipped with a flexible buffer mechanism. This buffer mechanism in the vacuum nozzle after contact with the chip will be compressed deformation, its own is a variable stroke. In this case, the lower stroke of the lifting frame is actually broken down into the compression of the buffer mechanism and the actual displacement of the chip. Because of the existence of the force-displacement characteristics of the buffer mechanism, the total stroke of the lifting frame monitored by the system and the real pressure acting on the chip lose the direct and determined correspondence.

[0008] Therefore, by pre-set stroke to control the pressure becomes extremely unreliable, the actual pressure applied may be much higher or lower than the pre-set value, seriously affecting the process consistency and product yield, the need to solve the problems existing in the traditional chip hot bar bonder in the chip suction and chip welding process. SUMMARY

[0009] 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 lower stroke, which can adaptively control the lower stroke according to the detected pressure, thereby accurately controlling the pressure applied to the chip by the vacuum nozzle in the chip suction and chip welding process.

[0010] 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 lower stroke, comprising a lifting frame, a hollow shaft slidably installed on the lifting frame along its 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;

[0011] The chip hot bar bonder based on double pressure control lower stroke further comprises a small range pressure sensor and a large range pressure sensor which are fixed in height relative to the lifting frame respectively, and the hollow shaft is connected with an elastic element and an action block; wherein,

[0012] The elastic element acts on the small range pressure sensor, and in the process of the lifting drive mechanism driving the lifting frame to descend, the vacuum nozzle drives the hollow shaft to ascend a pre-set stroke under the upward reaction force of the chip it presses, and then the action block abuts against the large range pressure sensor;

[0013] The small pressure signal detected by the small range pressure sensor is used to control the descending stroke of the lifting frame in the process of the vacuum nozzle sucking the chip;

[0014] The large pressure signal detected by the large range pressure sensor is used to control the descending stroke of the lifting frame in the process of the chip sucked by the vacuum nozzle being hot bar bonded on the substrate.

[0015] 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 drive mechanism, the rotating drive mechanism is installed on the lifting frame, the elastic element is an elastic coupling, and the output shaft of the rotating drive mechanism is connected with the small range pressure sensor and then connected with the upper end of the hollow shaft through the elastic coupling.

[0016] Further, a specific structure of the elastic coupling is provided, which realizes precise axial buffering while torque transmission and deviation compensation.

[0017] 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.

[0018] 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.

[0019] The circumferential angles of the first slits and the second slits are both greater than 90 degrees.

[0020] 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.

[0021] Further, in order to improve the angle accuracy of the hollow shaft and enable internal threading, the rotating drive mechanism is a hollow motor.

[0022] Further, a specific structure of a 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.

[0023] 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 is communicated with the first channel, and the suction nozzle piece suction channel is communicated with the second channel.

[0024] The suction nozzle piece fixing block is installed on the connecting rod, is provided with a ventilation channel communicated with the chip suction channel, and is provided with a suction slot communicated with the suction nozzle piece suction channel and surrounding the ventilation channel on the suction nozzle piece abutting surface.

[0025] 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 is communicated with the ventilation channel.

[0026] The heating component is used for heating the suction nozzle piece fixing block.

[0027] Further, another specific structure of a vacuum suction nozzle is provided, which comprises:

[0028] A connecting rod is provided with a chip suction channel communicated with the hollow shaft;

[0029] An adsorption part is connected with the connecting rod, and the vacuum suction channel is communicated with the chip suction channel.

[0030] A heating part is arranged for heating the adsorption part.

[0031] Further, in order to facilitate the connection of the vacuum suction nozzle and the hollow shaft, and to better dissipate heat, the vacuum suction nozzle further comprises a connecting sleeve, which is arranged above the heating part, and the vacuum suction nozzle is connected with the hollow shaft through the connecting sleeve, and the connecting sleeve is provided with a plurality of heat dissipation holes.

[0032] Further, in order to make the lifting frame lift more stably, and to avoid the lifting frame from falling due to power failure, the chip thermal compression bonding machine based on double-pressure control and downward stroke further comprises a fixing frame, the lifting driving mechanism is installed on the fixing frame, 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.

[0033] Further, a plurality of range pressure sensors are installed on an installation body, and a leveling mechanism for adjusting the parallelism of the plurality of range pressure sensors is arranged between the installation body and the plurality of range pressure sensors.

[0034] The present application also relates to a control method of a chip thermal compression bonding machine based on double-pressure control and downward stroke, comprising:

[0035] 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.

[0036] In the process that the lifting driving mechanism drives the lifting frame to descend to thermally compress and bond the chip sucked 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.

[0037] After the above technical scheme is adopted, the present application has the following beneficial effects:

[0038] 1. The application detects the pressure transmitted to the pressure sensor by the hollow shaft during the chip suction process and the chip thermal compression bonding process, and controls the lifting frame to stop descending when the pressure reaches the respective preset value. That is, the pressure of the vacuum suction nozzle applied to the chip during the chip suction process and the chip thermal compression bonding process is accurately controlled by adaptively controlling the descending stroke of the lifting frame, which is not affected by the thickness difference of the chip and the base material itself and the buffer deformation of the elastic mechanism, so as to provide moderate suction pressure during the chip suction process to ensure reliable pickup without damaging the back of the chip, and provide accurate and stable bonding pressure during the chip thermal compression bonding process to ensure the quality and consistency of the bonding interface; also accurately realize small pressure suction of the chip and large pressure mounting, avoid damage to the chip, and ensure the mounting effect;

[0039] 2. Based on the pressure control of the descending stroke of the lifting frame, the application simultaneously sets a small-range pressure sensor and a large-range pressure sensor, small pressure uses flexible measurement, and large pressure uses rigid measurement. Through ingenious structural design, the small-range pressure sensor and the large-range pressure sensor are used in a step-by-step manner to realize pressure measurement during the chip suction process and the chip thermal compression bonding process, respectively, and the small-range pressure sensor will not be overloaded and damaged due to the large pressure during the bonding process, realizing "measurement range and precision", so that the descending range of the lifting frame during the chip suction process and the chip thermal compression bonding process can be more accurately controlled, and accurate and stable bonding pressure can be better provided during the two processes. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The structure diagram of the chip thermal compression bonding machine based on the double-pressure control descending stroke of the application;

[0041] Figure 2 The sectional view of Figure 1 ;

[0042] Figure 3 The enlarged view of A part of Figure 2 ;

[0043] Figure 4 The structure diagram of the elastic coupling of the application;

[0044] Figure 5 The front view of Figure 4 ;

[0045] Figure 6 The top view of Figure 4 ;

[0046] Figure 7 The A-A sectional view of Figure 6 ;

[0047] Figure 8 Fig. 2 is an enlarged view of B part of Fig. 1; Figure 2 Fig. 3 is a structure diagram of a nozzle piece of the first vacuum nozzle of the present application;

[0048] Figure 9 Fig. 4 is a structure diagram of another view of the nozzle piece of the first vacuum nozzle of the present application;

[0049] Figure 10 Fig. 5 is a structure diagram of a fixing block of the nozzle piece of the first vacuum nozzle of the present application;

[0050] Figure 11 Fig. 6 is a structure diagram of the second vacuum nozzle of the present application;

[0051] Figure 12 Fig. 7 is a structure diagram of the second vacuum nozzle of the present application;

[0052] Fig. 8 is a structure diagram of the second vacuum nozzle of the present application;

[0053] 1. lifting frame;

[0054] 2. hollow shaft; 201, first channel; 202, second channel;

[0055] 3. vacuum nozzle; 301, connecting rod; 3011, chip adsorption channel; 3012, nozzle piece adsorption channel; 302, nozzle piece fixing block; 3020, nozzle piece adhering surface; 3021, air passage; 3022, suction slot; 3023, positioning pin; 3024, bolt hole; 303, nozzle piece; 3031, vacuum channel; 3032, positioning hole; 304, heating component; 305, adsorption part; 3051, vacuumizing channel; 306, connecting sleeve; 3061, heat dissipation hole; 307, heat insulation plate;

[0056] 4. lifting driving mechanism;

[0057] 5. small range pressure sensor;

[0058] 6. large range pressure sensor;

[0059] 7. elastic element; 701, first cut section; 7011, first cut; 702, second cut section; 7021, second cut; 703, connecting end; 7031, radial slot; 7032, clamping part; 70321, through hole;

[0060] 8. acting block;

[0061] 9. rotary driving mechanism;

[0062] 10. air floating bearing;

[0063] 11. fixing frame;

[0064] 12. tension spring;

[0065] 13. First electric slip ring;

[0066] 14. Second electric slip ring;

[0067] 15. Leveling mechanism. Detailed Implementation

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] Before the vacuum nozzle 3 contacts the chip and during the initial contact phase, a gap exists between the actuating block 8 and the large-range pressure sensor 6. As the vacuum nozzle 3, under the upward reaction force of the chip it is pressing, drives the hollow shaft 2 to rise relative to the lifting frame 1, this gap gradually decreases. After the preset upward stroke, the gap becomes zero. Figure 2 and Figure 3 (When the gap has become zero), the action block 8 abuts against the large-range pressure sensor 6, so that the large-range pressure sensor 6 can detect the large pressure signal.

[0075] It should be noted that, no matter the chip suction process or the chip welding process, the vacuum suction nozzle 3 applies downward pressure to the chip, and the small range pressure sensor 5 can detect a small pressure signal. In the chip suction process, the vacuum suction nozzle 3 needs to apply a small pressure to the chip, and the pressure applied by the vacuum suction nozzle 3 to the chip can meet the requirements before the acting block 8 rises with the hollow shaft 2 relative to the lifting frame 1 to abut against the large range pressure sensor 6. Therefore, in the process of the vacuum suction nozzle 3 suctioning the chip, the small pressure signal detected by the small range pressure sensor 5 controls the descending stroke of the lifting frame 1. In the chip welding process, the vacuum suction nozzle 3 needs to apply a large pressure to the chip, and the pressure applied by the vacuum suction nozzle 3 to the chip can meet the requirements after the acting block 8 abuts against the large range pressure sensor 6. Therefore, in the process of the vacuum suction nozzle 3 thermocompression bonding the chip it suctions to the substrate, the large pressure signal detected by the large range pressure sensor 6 controls the descending stroke of the lifting frame 1.

[0076] Specifically, the embodiment detects the pressure transmitted by the hollow shaft 2 to the pressure sensor in the chip suction process and the chip thermocompression bonding process, and controls the lifting frame 1 to stop descending when the pressure reaches the preset value. That is, the descending stroke of the lifting frame 1 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 by the vacuum suction nozzle 3 to the chip in the chip suction process and the chip thermocompression bonding process, so as to provide moderate suction pressure in the chip suction process to ensure reliable pickup without damaging the back of the chip, and provide accurate and stable welding pressure in the chip thermocompression bonding process to ensure the quality and consistency of the bonding interface; also accurately implement small pressure suction of the chip and large pressure mounting, avoid damage to the chip, and ensure the mounting effect.

[0077] In addition, the pressure applied by the vacuum suction nozzle 3 to the chip in the chip suction process is small, and the pressure applied by the vacuum suction nozzle 3 to the chip in the thermocompression bonding process is large, and there is a significant difference between the pressures in the two processes. If a small range pressure sensor is used to monitor the pressure in the two processes, the small range pressure sensor works in the optimal range of its range in the chip suction process, has high resolution and accurate feedback. However, in the chip thermocompression bonding process, the small range pressure sensor will be overloaded and damaged, or always output the maximum value. If a large range pressure sensor is used to monitor the pressure in the two processes, it can cover the large pressure required for thermocompression bonding and will not be overloaded. However, in the chip suction process, the actual pressure accounts for a small proportion of the full range of the large range pressure sensor, resulting in large resolution and relative error of the sensor, inaccurate control, and possibly leading to suction failure or chip damage.

[0078] In the embodiment, the small-range pressure sensor 5 and the large-range pressure sensor 6 are arranged simultaneously on the basis of the pressure control of the down stroke of the lifting frame 1, the small pressure is measured flexibly, the large pressure is measured rigidly, the small-range pressure sensor 5 and the large-range pressure sensor 6 are used in a ladder type through a clever structure design, the pressure measurement in the chip suction process and the chip hot pressure welding process is realized respectively, and the small-range pressure sensor 5 is not overloaded and damaged due to the large pressure in the welding process, the measurement range and precision are achieved, so that the down stroke of the lifting frame in the chip suction process and the chip welding process can be controlled more accurately, and the accurate and stable welding pressure is provided in the two processes better.

[0079] In the 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 is not limited thereto, and can be configured to other values as needed.

[0080] In the embodiment, the lifting driving mechanism 4 can be a mechanical arm, and can also be a linear module and the like.

[0081] In the embodiment, preferably, the small-range pressure sensor 5, the large-range pressure sensor 6 and the lifting driving mechanism 4 are connected to a controller respectively. The controller controls the down stroke of the lifting frame 1 in the process that the lifting driving mechanism 4 drives the lifting frame 1 to descend to make the vacuum suction nozzle 3 suction the chip according to the pressure signal fed back by the small-range pressure sensor 5, and controls the down stroke of the lifting frame 1 in the process that the lifting driving mechanism 4 drives the lifting frame 1 to descend to hot pressure weld the chip suctioned by the vacuum suction nozzle 3 on the substrate according to the pressure signal detected by the large-range pressure sensor 6.

[0082] In the embodiment, as shown in Figure 2 , Figures 8 to 11 , the vacuum suction nozzle 3 comprises:

[0083] A connecting rod 301 is provided with a chip suction channel 3011 and a 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 nozzle piece suction channel 3012 is communicated with the second channel 202.

[0084] A nozzle piece fixing block 302 is installed on the connecting rod 301, and is provided with a ventilation channel 3021 communicated with the chip suction channel 3011, and a suction groove 3022 communicated with the nozzle piece suction channel 3012 and surrounding the ventilation channel 3021 is arranged on a nozzle piece adhering surface 3020 thereof.

[0085] The suction nozzle sheet 303 is adsorbed to the suction nozzle sheet adhesion surface 3020 by the suction force slot 3022 after the suction nozzle sheet suction channel 3012 is vacuumized, and the vacuum channel 3031 of the suction nozzle sheet 303 is communicated with the air passage 3021;

[0086] The heating component 304 is used to heat the suction nozzle sheet fixing block 302, which can be but is not limited to a heating plate attached to the end surface of the suction nozzle sheet fixing block 302 away from the suction nozzle sheet adhesion surface 3020;

[0087] The connecting sleeve 306 is assembled above the heating component 304, and the hollow shaft 2 is connected to the vacuum suction nozzle 3 through the connecting sleeve 306 of the vacuum suction nozzle 3. The connecting sleeve 306 is provided with a plurality of heat dissipation holes 3061.

[0088] The suction nozzle sheet suction channel 3012 and the suction force slot 3022 jointly form an air path for adsorbing the suction nozzle sheet 303, and the chip suction channel 3011, the air passage 3021, and the vacuum channel 3031 of the suction nozzle sheet 303 jointly form an air path for adsorbing the chip.

[0089] The vacuum suction nozzle 3 in the embodiment can heat the suction nozzle sheet fixing block 302 through the heating component 304, heat the suction nozzle sheet 303, and accurately transfer heat from the suction nozzle sheet 303 to the chip and the substrate on which the chip is attached, thereby achieving hot-pressing attachment and eliminating the trouble of an external substrate heating mechanism.

[0090] Moreover, when replacing different specifications of chip products, the vacuum of the suction force slot 3022 is broken through the suction nozzle sheet suction channel 3012, so that the originally adsorbed suction nozzle sheet 303 automatically separates from the suction nozzle sheet adhesion surface 3020 of the suction nozzle sheet fixing block 302 under the action of gravity. Then, the suction nozzle sheet adhesion surface 3020 automatically adsorbs the new suction nozzle sheet 303 by vacuumizing the suction nozzle sheet suction channel 3012. In this way, the automatic replacement of the suction nozzle sheet 303 is achieved. Compared with manual disassembly and replacement, the replacement efficiency is higher, and the trouble of frequent shutdown of the chip hot-pressing welding machine is also eliminated.

[0091] In addition, since the suction nozzle sheet 303 is adsorbed on the suction nozzle sheet adhesion surface 3020 of the suction nozzle sheet fixing block 302 through surface-to-surface adhesion, the parallelism of the newly replaced suction nozzle sheet 303 can be well ensured, the trouble of later adjustment and calibration is eliminated, the stability of the quality of the attachment of various specifications of chips is well ensured, and the small-range pressure sensor 5 and the large-range pressure sensor 6 can accurately detect the pressure.

[0092] Furthermore, the suction nozzle sheet 303 is a very thin sheet, for example, 2 mm thick, and one suction nozzle sheet 303 is provided for each specification of chip, which greatly reduces the waste of physical resources.

[0093] Finally, the vacuum suction nozzle 3 is connected between the suction nozzle piece fixing block 302 and the suction nozzle piece 303 by negative pressure, which will not adversely affect the chip absorbed by the suction nozzle piece 303, and can still firmly absorb the suction nozzle piece 303 under high temperature (such as 200℃ or even 400℃ required for heat staking), and has high reliability.

[0094] In the embodiment, there are various ways to achieve the installation between the suction nozzle piece fixing block 302 and the connecting rod 301. For example, as shown in Figure 2 、 Figure 8 and Figure 11 , a part of the suction nozzle piece fixing block 302 is sleeved on the connecting rod 301, and at least one bolt hole 3024 is further provided, and the locking bolt is screwed in the bolt hole 3024 and abuts against the outer peripheral wall of the connecting rod 301, so that the installation between the suction nozzle piece fixing block 302 and the connecting rod 301 is achieved. Preferably, the bolt hole 3024 is provided with two bolt holes 3024 opposite in the radial direction of the connecting rod 301, so that the connecting rod 301 can be centered in the suction nozzle piece fixing block 302, and the weight of the entire vacuum suction nozzle 3 can be better balanced on both sides. The suction nozzle piece fixing block 302 and the connecting rod 301 can also be connected by threads.

[0095] In the embodiment, as shown in Figure 2 and Figure 8 , a communication channel can be provided in the suction nozzle piece fixing block 302, and the suction force groove 3022 is communicated with the suction nozzle piece absorbing channel 3012 through the communication channel. The peripheral wall of the end of the connecting rod 301 inserted into the suction nozzle piece fixing block 302 is provided with an opening of the suction nozzle piece absorbing channel 3012, and the communication channel includes a horizontal channel and a vertical channel which are communicated with each other, the horizontal channel is connected with the opening of the suction nozzle piece absorbing channel 3012, and the vertical channel is communicated with the suction force groove 3022. The suction force groove 3022 can be provided with one, two, three or the like. Figure 11 As shown in the knot structure, the suction force groove 3022 is provided with two rings which are communicated with each other from inside to outside, and the stable absorption of the suction nozzle piece 303 can be achieved.

[0096] In the embodiment, preferably, as shown in Figure 9 and Figure 11 , the suction nozzle piece fixing block 302 is provided with at least two positioning pins 3023, and the suction nozzle piece 303 is provided with positioning holes 3032 matched with the positioning pins 3023. In this way, the positioning of the suction nozzle piece 303 can be achieved by the cooperation of the positioning pins 3023 and the positioning holes 3032 in the process of automatically absorbing the suction nozzle piece 303, so that the suction nozzle piece 303 is absorbed at the expected position of the suction nozzle piece abutting surface 3020. Among them, the two positioning pins 3023 can be located on one diagonal line of the suction nozzle piece abutting surface 3020 of the suction nozzle piece fixing block 302.

[0097] In addition, in the process of automatically adsorbing the suction nozzle sheet 303 by the vacuum suction nozzle 3, the alignment of the suction nozzle sheet bonding surface 3020 and the suction nozzle sheet 303 is realized by automatic positioning of the camera of the chip thermal compression bonding machine. In order to enable the chip thermal compression bonding machine to better position the suction nozzle sheet bonding surface 3020 and the suction nozzle sheet 303, and better realize the alignment of the suction nozzle sheet bonding surface 3020 and the suction nozzle sheet 303, the suction nozzle sheet fixing block 302 and the suction nozzle sheet 303 are respectively provided with identification holes for identification by the camera, and the identification holes on the suction nozzle sheet fixing block 302 and the suction nozzle sheet 303 can be aligned with each other.

[0098] In the embodiment, preferably, as shown in Figure 8 The openings of the chip adsorption channel 3011 and the suction nozzle sheet adsorption channel 3012 away from the suction nozzle sheet fixing block 302 are respectively located on the end face and the peripheral wall of the connecting rod 301.

[0099] In this way, the components of the chip thermal compression bonding machine respectively communicating with the chip adsorption channel 3011 and the suction nozzle sheet adsorption 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 suction nozzle 3 can also be formed on the peripheral wall.

[0100] Connecting the connecting sleeve 306 to the chip thermal compression bonding machine realizes the installation of the entire vacuum suction nozzle 3 on the chip thermal compression bonding machine. The connecting sleeve 306 is provided to facilitate the installation of the vacuum suction 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 suction 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 suction nozzle sheet fixing block 302.

[0101] In the embodiment, as shown in Figure 1 and Figure 2 The chip thermal compression bonding machine based on double-pressure control downstroke further comprises a fixing frame 11, the lifting driving mechanism 4 is installed on the fixing frame 11, the lifting frame 1 is slidably installed on the fixing frame 11, and at least two tension springs 12 are arranged between the fixing frame 11 and the lifting frame 1.

[0102] Specifically, the partial weight of the moving component is offset by the tension spring 12, so that the moving component will not fall downward due to the weight in the power-off state.

[0103] Embodiment two: The main difference between the embodiment and embodiment one is that the structure of the vacuum suction nozzle 3 used is different. As shown in Figure 12As shown, the suction nozzle fixing block 302 and suction nozzle 303 of the vacuum nozzle 3 in Embodiment 1 are replaced by an integrally formed suction part 305. The connecting rod 301 has only a chip suction channel 3011, and the entire hollow shaft 2 has only a first channel 201 that connects to the chip suction channel 3011. The hollow cylinder of the suction part 305 passes through the heating component 304 and is threadedly connected to the connecting rod 301. The vacuum channel 3051 of the suction part 305 connects to the chip suction channel 3011 and connects to the first channel 201 of the hollow shaft 2 through the chip suction channel 3011.

[0104] The vacuum nozzle 3 has a simple structure.

[0105] Example 3: Based on Example 1 or Example 2, such as... Figures 1 to 7 As shown, the chip hot press welding machine based on dual pressure control downward stroke also includes a rotary drive mechanism 9. The rotary drive mechanism 9 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 the small range pressure sensor 5 and then connected to the upper end of the hollow shaft 2 through the elastic coupling.

[0106] The rotary drive mechanism 9 allows for adjustment of the angle of the adsorbed chip as needed, improving operational flexibility. A flexible coupling transmits torque, absorbs and buffers axial impacts from the hollow shaft 2, protecting the chip and transmitting pressure to the small-range pressure sensor 5.

[0107] Preferably, such as Figures 2-7 As shown, the flexible coupling includes a metal sleeve, and the metal sleeve is provided with a first slit section 701 and a second slit section 702 along the axial direction; wherein,

[0108] The first slit segment 701 has a plurality of first slits 7011 that are spaced apart along the axial direction and staggered in a first direction;

[0109] 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 first slit 7011 is formed by cutting along the first direction, and the second slits 7021 are formed by cutting along the second direction.

[0110] The circumferential angles of the first slit 7011 and the second slit 7021 are both greater than 90 degrees, preferably 135 degrees.

[0111] Specifically, the plurality of first slits 7011 of the first slit section 701 are staggered and opposite in the first direction, and the plurality of 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.

[0112] For the convenience of description, the first direction is taken as the front-back direction, and the second direction is taken as the left-right direction.

[0113] The circumferential angle of the first slit 7011 is greater than 90 degrees, and the first slits 7011 distributed on the left and right 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 back 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 back positions.

[0114] The circumferential angle of the second slit 7021 is greater than 90 degrees, and the second slits 7021 distributed on the left and right sides of the second slit section 702 coincide in the front and back 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 back positions, which can provide effective axial precise buffering in the front and back positions and provide the rigidity required for torque transmission of the coupling in the left and right positions.

[0115] 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.

[0116] In the case where the circumferential angles of the first slit 7011 and the second slit 7021 are both 135 degrees, the first slit 7011 is sparse in the front and back 90-degree central angle ranges of the metal sleeve and dense in the left and right 90-degree central angle ranges, and the second slit 7021 is sparse in the left and right 90-degree central angle ranges of the metal sleeve and dense in the front and back 90-degree central angle ranges. In the case where the circumferential angles of the first slit 7011 and the second slit 7021 are both 135 degrees, the entire coupling can achieve axial precise buffering in all directions in the entire circumference while meeting the requirement of full-directional rigidity in the circumference, further improving the performance.

[0117] As shown in FIG. 6, the first slit section 701 and the second slit section 702 are arranged in the metal sleeve 1 in the form of a ring. Figures 2 to 7As shown, the two ends of the metal sleeve are both connecting ends 703, each of which is divided into two clamping parts 7032 by a radial slot 7031, and the two sides of the two clamping parts 7032 are respectively provided with through holes 70321 for the locking bolts to pass through.

[0118] In use, the small-range pressure sensor 5 and the shaft of the hollow shaft 2 are respectively inserted into the corresponding connecting ends 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 another 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.

[0119] In this embodiment, as shown in Figure 2 and Figure 3 , an air floating bearing 10 can also be arranged between the hollow shaft 2 and the lifting frame 1, and the air floating bearing 10 reduces the friction when the hollow shaft 2 rotates and moves up and down, thereby improving the pressure accuracy and position accuracy.

[0120] In this embodiment, the large-range pressure sensor 6 can be fixedly installed on the lifting frame 1, can also be fixedly installed on the outer ring of the air floating bearing 10, and can also be 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.

[0121] In this embodiment, the component carrying the large-range pressure sensor 6 is referred to as a mounting body, and preferably, as shown in Figure 2 and Figure 3 , a leveling mechanism 15 is arranged between the mounting body and the large-range pressure sensor 6.

[0122] 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 can be accurately realized.

[0123] 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 with 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 the corresponding leveling bolts, the leveling of the large-range pressure sensor 6 can be realized.

[0124] In this embodiment, as shown in Figure 2As shown, the rotary driving 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.

[0125] In the present 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.

[0126] Embodiment Four: A control method of a chip thermal compression bonding machine based on double-pressure control downstroke, according to any one of Embodiment One or Embodiment Two or Embodiment Three, comprising:

[0127] In the process of driving the lifting frame 1 to descend by the lifting driving 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 driving mechanism 4 is controlled to stop driving the lifting frame 1 to descend.

[0128] In the process of driving the lifting frame 1 to descend by the lifting driving mechanism 4 to thermally compression bond the chip adsorbed 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 driving mechanism 4 is controlled to stop driving the lifting frame 1 to descend; the second pressure value is greater than the first pressure value.

[0129] 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 content in the specification, and must be determined according to the scope of claims.

Claims

1. A chip thermal compression bonding machine based on double pressure control down stroke, comprising a lifting frame (1), a hollow shaft (2) slidably installed on the lifting frame (1) along the axial direction, a vacuum nozzle (3) installed at the lower end of the hollow shaft (2), and a lifting drive mechanism (4) connected with the lifting frame (1) to drive the lifting frame (1) to lift; characterized in that, further comprising a small range pressure sensor (5) and a large range pressure sensor (6) fixed in height relative to the lifting frame (1) respectively, and the hollow shaft (2) is connected with an elastic element (7) and an action block (8); wherein, the elastic element (7) acts on the small range pressure sensor (5), and in 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 ascend a preset stroke relative to the lifting frame (1) under the upward reaction force of the chip pressed thereon, and then the action block (8) abuts against the large range pressure sensor (6). 2.The chip thermal compression bonding machine based on double pressure control down stroke according to claim 1, characterized in that, further comprising a rotary drive mechanism (9) installed on the lifting frame (1), the elastic element (7) is an elastic coupling, and the output shaft of the rotary drive 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. 3.The chip thermal compression bonding machine based on double pressure control down stroke according to claim 2, characterized in that, the elastic coupling comprises a metal sleeve, the metal sleeve is provided with a first slit section (701) and a second slit section (702) in the axial direction; wherein, the first slit section (701) has a plurality of first slits (7011) arranged in the axial direction and staggered opposite in a first direction; the second slit section (702) has a plurality of second slits (7021) arranged in the axial direction and staggered opposite in a second direction; the second direction is perpendicular to the first direction; and the circumferential angle of the first slit (7011) and the second slit (7021) is greater than 90 degrees. 4.The chip thermal compression bonding machine based on double pressure control down stroke according to claim 2, characterized in that, an air floating bearing (10) is arranged between the hollow shaft (2) and the lifting frame (1). 5.The chip thermal compression bonding machine based on double pressure control down stroke according to claim 2, characterized in that, the rotary drive mechanism (9) is a hollow motor. 6.The chip thermal compression bonding machine based on double pressure control down stroke according to claim 1, characterized in that, the vacuum nozzle (3) comprises: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A connecting rod (301) is provided with a chip adsorption channel (3011) and a nozzle piece adsorption channel (3012), and the hollow shaft (2) is provided with a first channel (201) and a second channel (202), the chip adsorption channel (3011) is communicated with the first channel (201), and the nozzle piece adsorption channel (3012) is communicated with the second channel (202); A nozzle piece fixing block (302) is installed on the connecting rod (301), which is provided with a ventilation channel (3021) communicated with the chip adsorption channel (3011), and a suction groove (3022) communicated with the nozzle piece adsorption channel (3012) and surrounding the ventilation channel (3021) is arranged on the nozzle piece abutting surface (3020) of the nozzle piece fixing block (302); A nozzle piece (303) is adsorbed to the nozzle piece abutting surface (3020) by the suction groove (3022) after the nozzle piece adsorption channel (3012) is vacuumized, and the vacuum channel (3031) of the nozzle piece (303) is communicated with the ventilation channel (3021); A heating component (304) is used for heating the nozzle piece fixing block (302).

7. The chip thermal compression bonding machine based on double pressure control down stroke according to claim 1, wherein the vacuum suction nozzle (3) comprises: A connecting rod (301) is provided with a chip adsorption channel (3011) communicated with the hollow shaft (2); An adsorption part (305) is connected to the connecting rod (301), and the vacuum channel (3051) of the adsorption part (305) is communicated with the chip adsorption channel (3011); A heating component (304) is used for heating the adsorption part (305).

8. The chip thermal compression bonding machine based on double pressure control down stroke according to claim 6 or 7, wherein the vacuum suction nozzle (3) further comprises a connecting sleeve (306) assembled above the heating component (304), the vacuum suction nozzle (3) is connected to 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).

9. The chip thermal compression bonding machine based on double pressure control down stroke according to claim 1, further comprising a fixing frame (11), wherein the lifting driving mechanism (4) is installed on the fixing frame (11), the lifting frame (1) is slidably installed on the fixing frame (11), and at least two tension springs (12) are arranged between the fixing frame (11) and the lifting frame (1).

10. The chip thermal compression bonding machine based on double pressure control down stroke according to claim 1, wherein the large range pressure sensor (6) is installed on a mounting body, and a leveling mechanism (15) for adjusting the parallelism of the large range pressure sensor (6) is arranged between the mounting body and the large range pressure sensor (6).

11. A control method of the chip thermal compression bonding machine based on double pressure control down stroke according to any one of claims 1-10, comprising: ​ ​ ​ ​ ​ In the process that the lifting driving mechanism (4) drives the lifting frame (1) to descend to adsorb the chip, a small pressure signal detected by the small range pressure sensor (5) is acquired, and when a pressure value corresponding to the small pressure signal reaches a preset first pressure value, the lifting driving mechanism (4) is controlled to stop driving the lifting frame (1) to descend. In the process that the lifting driving mechanism (4) drives the lifting frame (1) to descend to heat press and weld the chip adsorbed by the vacuum suction nozzle (3) on the substrate, a large pressure signal detected by the large range pressure sensor (6) is acquired, and when a pressure value corresponding to the large pressure signal reaches a preset second pressure value, the lifting driving 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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