Chip mounting method and chip mounting device

Abstract

The present invention relates to the field of semiconductor manufacturing technology, and provides a chip mounting method and a chip mounting device. The chip mounting method includes the following steps: S1: The chip mounting head adsorbs a first substrate, and drives the chip mounting head to move towards the direction close to a second substrate through a motor; S2: Measure the real-time distance from the first substrate to the second substrate. If the real-time distance is less than a first set distance and greater than zero, the motor enters a torque control mode; if the real-time distance is zero, step S3 is executed; S3: The motor enters a pressure control mode. Through the cooperation of the above three control modes, on the one hand, a high bonding efficiency is ensured, and at the same time, the overpressure problem at the moment when the first substrate and the second substrate come into contact is solved, and it is also beneficial to the precise control of the chip mounting pressure.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and particularly relates to a chip bonding method and a chip bonding device. Background Art

[0002] Bonding technology can bond substrates of different materials together. Bonding is an important process in the three-dimensional processing of semiconductor devices. The main process steps of bonding include the treatment of the substrate surface, the alignment and chip bonding of the substrates, and the final substrate bonding. Bonding is not only a packaging technology in microsystem technology, but also an organic part of three-dimensional device manufacturing, and is applied in both the front-end process and the back-end process of device manufacturing. The most common current bonding applications are the bonding of silicon wafers to silicon wafers, the bonding of silicon wafers to glass substrates, and the bonding of chips to substrates.

[0003] With the rapid development of semiconductor and integrated circuit manufacturing equipment and manufacturing processes, 2.5D and full 3D packaging technologies have become increasingly mature; in packaging technology, the alignment and chip bonding before the bonding process will determine the feasibility of subsequent processes. Alignment and chip bonding is to align and bond two substrates that need to be bonded.

[0004] When aligning and chip bonding, the required bonding force is relatively small, generally around 10 N, and overpressure is not allowed because excessive pressure is likely to damage the substrate.

[0005] In the existing chip bonding methods, it is difficult to accurately control the bonding force. During the chip bonding process, overpressure is likely to occur and damage the substrate when the two substrates come into contact. For the method using an AC servo motor and a lead screw to control the bonding force, it is required to be fast and accurate, and overcharging is not allowed when they come into contact, which poses a challenge.

[0006] To solve the above problems, the present invention provides a chip bonding method and a chip bonding device to meet the requirements of small-force chip bonding control, fast pressing without overpressure, and accurate chip bonding. Summary of the Invention

[0007] The purpose of the present invention is to provide a chip bonding method and a chip bonding device to meet the requirements of small-force chip bonding control, fast pressing without overpressure, and accurate chip bonding.

[0008] The present invention provides a chip bonding method, including the following steps:

[0009] S1: The chip bonding head adsorbs the first substrate, and drives the chip bonding head to move towards the direction close to the second substrate through a motor;

[0010] S2: Measure the real-time distance from the first substrate to the second substrate;

[0011] If the real-time distance is less than the first set distance and greater than zero, the motor enters the torque control mode;

[0012] In the torque control mode, if the real-time distance is less than the first set distance and greater than the second set distance, the output torque of the motor is negatively correlated with the real-time distance, and the second set distance is less than the first set distance; if the real-time distance is less than or equal to the second set distance and greater than zero, the output torque of the motor is positively correlated with the real-time distance;

[0013] If the real-time distance is zero, step S3 is executed;

[0014] S3: The motor enters the pressure control mode:

[0015] In the pressure control mode, the real-time pressure of the patch head is detected, and the pressure difference between the target pressure and the real-time pressure is calculated; when the pressure difference is greater than zero, the motor drives the first substrate to move towards the second substrate to increase the real-time pressure; when the pressure difference is equal to zero, the patch head releases the first substrate, and the motor drives the patch head to move away from the second substrate to relieve the pressure.

[0016] Optionally, between step S1 and step S2, there is also step S1-1;

[0017] S1-1: Detect the real-time pressure of the patch head, and calculate the pressure difference between the target pressure and the real-time pressure;

[0018] If the pressure difference does not change with the movement of the first substrate, it is considered that the first substrate and the second substrate are not in contact, and step S2 is executed;

[0019] If the pressure difference changes with the movement of the first substrate, it is considered that the first substrate and the second substrate are in contact, and step S3 is executed.

[0020] Optionally, in step S2, if the real-time distance is greater than or equal to the first set distance, the motor enters the positioning control mode to drive the first substrate to quickly move to a position where the distance from the second substrate is the first set distance.

[0021] Optionally, in step S3, when the motor is in the pressure control mode, the output torque of the motor is 0.03 N·m to -0.12 N·m.

[0022] Optionally, in step S2, when the real-time distance is less than the first set distance and greater than the second set distance, the peak value of the output torque of the motor is 0.02 N·m to 0.04 N·m.

[0023] Optionally, in step S2, if the real-time distance is less than or equal to the second set distance, the minimum value of the output torque of the motor is -0.03 N·m to -0.08 N·m.

[0024] Optionally, when in the torque control mode, the motor adopts PID control; and / or when in the pressure control mode, PID control is adopted.

[0025] Optionally, the motor is a servo motor.

[0026] The present invention also provides a chip mounter, including a motor, a chip head, an alignment table, a pressure detection unit, a distance detection unit, and a controller;

[0027] The alignment table is used to carry a second substrate;

[0028] The chip head is used to adsorb a first substrate;

[0029] The chip head faces the alignment table, and the motor is used to drive the chip head to move in a direction close to or away from the alignment table;

[0030] The pressure detection unit is arranged on the chip head and is used to detect the real-time pressure of the chip head;

[0031] The distance detection unit is arranged on the chip head and / or the alignment table and is used to detect the real-time distance between the first substrate and the second substrate;

[0032] The controller is connected to the motor, the pressure detection unit, and the distance detection unit;

[0033] The controller has a torque control mode and a pressure control mode;

[0034] If the real-time distance is less than a first set distance and greater than zero, the controller controls the motor through the torque control mode; in the torque control mode, if the real-time distance is less than the first set distance and greater than a second set distance, the output torque of the motor is negatively correlated with the real-time distance, and the second set distance is less than the first set distance; if the real-time distance is less than or equal to the second set distance and greater than zero, the output torque of the motor is positively correlated with the real-time distance;

[0035] If the real-time distance is zero or when the pressure difference between the real-time pressure and the target pressure changes, the controller controls the motor through the pressure control mode; in the pressure control mode, when the pressure difference is greater than zero, the motor drives the first substrate to move in a direction close to the second substrate; when the pressure difference is equal to zero, the chip head releases the first substrate, and the motor drives the chip head to move in a direction away from the second substrate to relieve pressure.

[0036] Optionally, the controller further has a positioning control mode; if the real-time distance is greater than or equal to the first set distance, the controller controls the motor through the positioning control mode to drive the first substrate to quickly move to a position at a first set distance from the second substrate.

[0037] In summary, a chip mounting method of the present invention includes the following steps: S1: The chip mounting head adsorbs the first substrate and drives the chip mounting head to move in a direction close to the second substrate through the motor; S2: Measure the real-time distance from the first substrate to the second substrate. If the real-time distance is less than the first set distance and greater than zero, the motor enters the torque control mode; in the torque control mode, if the real-time distance is less than the first set distance and greater than the second set distance, the output torque of the motor is negatively correlated with the real-time distance, and the second set distance is less than the first set distance; if the real-time distance is less than or equal to the second set distance and greater than zero, the output torque of the motor is positively correlated with the real-time distance; if the real-time distance is zero, execute step S3; S3: The motor enters the pressure control mode: in the pressure control mode, detect the real-time pressure of the chip mounting head and calculate the pressure difference between the target pressure and the real-time pressure; when the pressure difference is greater than zero, the motor drives the first substrate to move in a direction close to the second substrate to increase the real-time pressure; when the pressure difference is equal to zero, the chip mounting head releases the first substrate, and the motor drives the chip mounting head to move away from the second substrate to relieve the pressure.

[0038] With such a configuration, in the above chip mounting method, the initial displacement of the chip mounting head is usually at a relatively far distance from the second substrate, so that the initial distance from the first substrate to the second substrate is much greater than the first set distance. Therefore, the motor is controlled through the positioning control mode to respond quickly, so that the first substrate can quickly move to a position close to the second substrate, reducing the chip mounting time and improving the chip mounting efficiency;

[0039] When the real-time distance is less than, the motor enters the torque control mode. If the real-time distance is less than the first set distance and greater than the second set distance, the output torque of the motor is negatively correlated with the real-time distance. Then, when the first substrate is closer to the second substrate, the output torque of the motor is greater. In this process, on the one hand, the better output characteristics of the motor can be ensured, and on the other hand, the reliability of the motor operation can also be improved;

[0040] If the real-time distance is less than or equal to the second set distance, the first substrate exceeds the contact surface corresponding to the second set distance, and the output torque of the motor is positively correlated with the real-time distance; then, when the first substrate is closer to the second substrate, the output torque of the motor is smaller, so that the first substrate and the second substrate are gently contacted, thus well controlling the overpressure problem at the moment when the first substrate and the second substrate contact.

[0041] When the real-time distance is zero, that is, when the first substrate and the second substrate are in contact, the motor enters the pressure control mode. In this mode, emphasis is placed on controlling the sticking force to ensure that the real-time pressure accurately approaches the target pressure, thereby achieving precise control of the sticking pressure.

[0042] Through the coordination of the above three control modes, on the one hand, a high fitting efficiency is ensured, and at the same time, the overpressure problem at the moment when the first substrate and the second substrate come into contact is solved. It is also conducive to the precise control of the sticking pressure to meet the requirements of small-force sticking control, achieving fast pressing without overpressure and precise sticking. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Structural schematic diagram of a sticking device according to an embodiment of the present invention;

[0044] Figure 2 Sticking schematic diagram of a sticking device according to an embodiment of the present invention;

[0045] Figure 3 Flowchart of a sticking method according to an embodiment of the present invention;

[0046] Figure 4 Control schematic diagram of a sticking method according to an embodiment of the present invention.

[0047] Among them, in the drawings:

[0048] 10 - Motor;

[0049] 20 - Sticking head;

[0050] 30 - Alignment stage;

[0051] 40 - Pressure detection unit;

[0052] 50 - Distance detection unit;

[0053] 60 - Controller;

[0054] 70 - Leveling device;

[0055] 80 - First substrate;

[0056] 90 - Second substrate;

[0057] L - Real-time distance; L1 - First set distance; L2 - Second set distance. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0058] The following further elaborates in detail on the sticking method proposed by the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise scales, only for the purpose of conveniently and clearly assisting in explaining the objectives of the embodiments of the present invention.

[0059] As used in the present invention, the singular forms "a", "an", and "the" include plural referents, the term "or" is generally used in the sense of including "and / or", the term "several" is generally used in the sense of including "at least one", the term "at least two" or "plural" is generally used in the sense of including "two or more", in addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third" may explicitly or implicitly include one or at least two of such features. In addition, as used in the present invention, "mounted", "connected", "coupled", and an element "disposed" on another element should be understood in a broad sense, generally only indicating that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the two elements may be directly or indirectly connected, coupled, cooperated or transmitted through an intermediate element, and cannot be construed as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise expressly specified. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used with respect to the exemplary embodiments as shown in the figures, the upward or upper direction is towards the top of the corresponding figure, and the downward or lower direction is towards the bottom of the corresponding figure.

[0060] Please refer to Figure 1 As shown, this embodiment provides a chip mounter, including a motor 10, a chip head 20, an alignment stage 30, a pressure detection unit 40, a distance detection unit 50, and a controller 60;

[0061] The chip head 20 is used to adsorb the first substrate 80; the chip head 20 generally adsorbs the first substrate 80 by means of vacuum adsorption. The chip head 20 is, for example, a vacuum adsorption disc, which includes an adsorption disc, and an adsorption groove is provided on the lower surface of the adsorption disc. The adsorption groove is connected to an external vacuum device through a vacuum adsorption channel. By evacuating the vacuum device, a negative pressure environment is formed in the adsorption groove so that the first substrate 80 is adsorbed on the lower surface of the adsorption disc. In other alternative embodiments, the chip head 20 may also adopt other known adsorption structures.

[0062] In this embodiment, the chip head 20 is further equipped with a leveling device 70 to adjust the levelness of the adsorption end of the chip head 20. The chip head 20 and the leveling device 70 both adopt existing structures and will not be elaborated here.

[0063] In this embodiment, the motor 10 is a servo motor, which is in transmission cooperation with the chip mounter head 20 through a lead screw-nut pair. That is, the motor 10 drives the lead screw to rotate, and the lead screw is in threaded transmission cooperation with the chip mounter head 20. The rotational motion is converted into a linear motion of the chip mounter head 20 through the lead screw, thereby driving the chip mounter head 20 to move linearly. In this embodiment, the chip mounter head 20 faces the alignment stage 30, and the chip mounter head 20 is located directly above the alignment stage 30. Moreover, the motor 10 is used to drive the chip mounter head 20 to move vertically to drive the first substrate 80 to approach or move away from the alignment stage 30.

[0064] In this embodiment, the alignment stage 30 is used to carry the second substrate 90; the motor 10 drives the chip mounter head 20 to drive the first substrate 80 to move downward and then bond with the second substrate 90. The alignment stage 30 can have multi-degree-of-freedom adjustment functions, such as the degrees of freedom of horizontal movement and rotational movement, to drive the second substrate 90 to move and align with the first substrate 80. The alignment stage 30 also uses an existing workbench, which will not be elaborated here. The first substrate 80 and the second substrate 90 refer to two devices for bonding. For example, the first substrate 80 and the second substrate 90 can be the bonding of silicon wafers, or the bonding of a silicon wafer and a glass substrate, or the bonding of a substrate and a chip, etc. The first substrate 80 and the second substrate 90 can be devices in the front-end process of semiconductor manufacturing or devices in the back-end process of semiconductor manufacturing.

[0065] The pressure detection unit 40 is arranged on the chip mounter head 20 and is used to detect the real-time pressure of the chip mounter head 20. When the first substrate 80 and the second substrate 90 are not in contact, the chip mounter head 20 is not subjected to an external force, so the real-time pressure corresponding to the chip mounter head 20 at this time can be used as the initial zero value. The pressure detection unit 40 can use existing pressure sensors, such as piezoresistive pressure sensors, capacitive pressure sensors and other existing sensors.

[0066] The distance detection unit 50 is arranged on the chip mounter head 20 and is used to detect the real-time distance between the first substrate 80 and the second substrate 90. The distance detection unit 50 can use an infrared ranging sensor, an ultrasonic distance sensor, etc. The structures and usage methods of the voltage sensor and the distance sensor are all prior arts and will not be elaborated here.

[0067] Alternatively, the above-mentioned distance detection unit 50 can also be arranged on the alignment stage 30.

[0068] In other alternative embodiments, the distance detection unit 50 can also use a transmissive laser sensor. At this time, the distance detection unit 50 is arranged on the chip mounter head 20 and the alignment stage 30. The laser emitting end of the distance detection unit 50 can be arranged on the chip mounter head 20, and the laser receiving end of the distance detection unit 50 can be arranged on the alignment stage 30.

[0069] The controller 60 communicates or is electrically connected to the motor 10, the pressure detection unit 40, and the distance detection unit 50.

[0070] In this embodiment, the controller 60 is a PID controller.

[0071] For the hardware structure, the controller 60 includes at least one processor. The processor can be a Central Processing Unit (CPU), or can also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0072] The at least one processor can communicate with a plurality of peripheral devices via a bus subsystem. These peripheral devices can include a storage system, a user interface input device, a user interface output device, and a network interface.

[0073] The network interface provides an interface to an external network and / or other devices. The network interface includes one or more interfaces known in the art, such as LAN, WLAN, Bluetooth, and other wired and wireless interfaces, etc.

[0074] The user interface input device can include a keyboard, a pointing device such as a mouse, a trackball, a touchpad, or a graphics tablet, a scanner, a foot pedal, a joystick, a touch screen embedded in a display, an audio input device such as a voice recognition system, a microphone, and other types of input devices. Generally speaking, the term "input device" is intended to include various conventional and proprietary devices and means for inputting information into the controller.

[0075] The user interface output device can include a display subsystem, a printer, a fax machine, or a non-visual display such as an audio output device. The display subsystem can be a flat panel device, such as a Liquid Crystal Display (LCD), a Light Emitting Diode (LED) display, a touch screen display, etc. The display subsystem can also provide a non-visual display via, for example, an audio output device. Generally speaking, the term "output device" is intended to include various conventional and proprietary devices and means for outputting information from the controller 60 to the user.

[0076] The storage system can store the basic programming and data structures for implementing the various functions of the present invention. For example, as described herein, the databases and modules that implement the functions of the method of the present invention can be stored in the storage system. These software modules are typically executed by a processor. In a distributed environment, the software modules can be stored on multiple computer systems and executed by the processors of multiple computer systems. The storage system generally includes a memory subsystem and a file storage system. The memory subsystem generally includes multiple memories, including a main random access memory (RAM) for storing instructions and data during program execution and a read-only memory (ROM) for storing fixed instructions therein. The file storage subsystem provides permanent (non-volatile) storage for program and data files. The file storage system can include a hard disk drive and associated removable media, a compact disc (CD) drive, an optical drive, a DVD, solid-state memory, and / or other removable media. One or more of these drives can be located at a remote location on other connected computers at other sites coupled to the controller 60. The modules that implement the functions of the present invention can be stored by the file storage system.

[0077] The bus subsystem provides components for enabling the various components and subsystems of the controller 60 to communicate with each other as expected. The various subsystems and components of the controller 60 do not have to be in the same physical location but can be distributed at various locations within a distributed network. The bus subsystem can be a single bus or multiple buses can be provided based on requirements.

[0078] The hardware structure of the controller 60 described above is only intended as an example to illustrate only one embodiment of the present invention. Due to the ever-changing nature of computers and networks, in other alternative embodiments, the controller 60 can also have some differences from the configuration of the controller depicted above, which will not be elaborated here.

[0079] The controller 60 has a position control mode, a torque control mode, and a pressure control mode.

[0080] Please refer to Figure 2 As shown, the real-time distance between the first substrate 80 and the second substrate 90 is L, and the real-time distance L is obtained by detecting with the distance detection unit 50. The first set distance is L1, and the second set distance is L2. Wherein the first set distance L1 is less than L, and L2 is less than the first set distance L1. Both the first set distance L1 and the second set distance L2 are less than 1 mm. For example, the first set distance L1 is set to 200 um, and the second set distance L2 is set to 100 um. The specific values of the first set distance L1 and the second set distance L2 can be set based on actual chip mounting requirements.

[0081] When the placement head 20 moves downward from top to bottom, when the real-time distance L is greater than or equal to the first set distance L1, the controller 60 controls the motor 10 through the positioning control mode. In the positioning control mode, it is used to drive the first substrate 80 to quickly move to a position where the distance from the second substrate 90 is the first set distance L1. In the positioning control mode, the placement head 20 can be controlled to run at high speed through the motor 10. At this time, there is no need to particularly consider the output torque of the motor 10, so that the first substrate 80 quickly runs to the position where the distance from the second substrate 90 is the first set distance L1.

[0082] Preferably, when the motor 10 drives the first substrate 80 to be about to reach the above position, the motor 10 decelerates and the output torque gradually decreases, so that when running to this position, the output torque of the motor 10 approaches zero (or equals zero), and the running speed of the motor 10 driving the placement head 20 also approaches zero (or equals zero).

[0083] Under normal circumstances, the initial displacement distance of the placement head 20 from the second substrate 90 is relatively far, so that the initial distance from the first substrate 80 to the second substrate 90 is much greater than the first set distance L1. Therefore, the motor is controlled quickly through the positioning control mode to make the first substrate 80 quickly run to a position close to the second substrate 90, so as to reduce the placement time and improve the placement efficiency.

[0084] When the real-time distance L is less than the first set distance L1, the controller 60 controls the motor 10 through the torque control mode, and the motor 10 enters the torque control mode. The torque control mode adopts PID1 control, which can act forward and backward.

[0085] If the real-time distance L is less than the first set distance L1 and greater than the second set distance L2, PID1 controls the torque and acts forward. The output torque of the motor 10 is negatively correlated with the real-time distance L. Then, when the first substrate 80 is closer to the second substrate 90, the output torque of the motor 10 is greater. In this process, on the one hand, the better output characteristics of the motor 10 can be ensured, and on the other hand, the running reliability of the motor 10 is also improved.

[0086] If the real-time distance L is less than or equal to the second set distance L2, the first substrate 80 exceeds the contact surface corresponding to the second set distance L2, and PID1 acts in the reverse direction for torque control. The output torque of the motor 10 is positively correlated with the real-time distance L. Then, when the first substrate 80 is closer to the second substrate 90, the output torque of the motor 10 is smaller, so that the first substrate 80 and the second substrate 90 gently contact, thus well controlling the overpressure problem at the moment when the first substrate 80 and the second substrate 90 contact.

[0087] Among them, PID (Proportional Integral Derivative) is a control system that controls through proportion, integral, and derivative. PID control is one of the earliest developed control strategies, with advantages such as simple principle, strong robustness, and wide application range. It is a control system with mature technology and the most extensive application, and is widely used in industrial process control, especially suitable for deterministic control systems that can establish accurate mathematical models.

[0088] When the real-time distance L is zero, that is, when the first substrate 80 and the second substrate 90 are in contact, the controller 60 controls the motor 10 through the pressure control mode, and the motor 10 enters the pressure control mode. In this mode, it is used to control the sticking force. The real-time pressure received by the sticking head 20 is measured by the pressure detection unit 40, and the target pressure for sticking is set. For example, the target pressure is 10 N. Calculate the pressure difference between the target pressure and the real-time pressure (target pressure - real-time pressure).

[0089] When passing through the torque control mode, it is possible to make the pressure at the moment when the first substrate 80 and the second substrate 90 come into contact smaller, and this pressure is less than the target pressure. Then, in the pressure control mode, the initial value of the pressure difference is greater than zero. When the pressure difference is greater than zero, the motor 10 drives the first substrate 80 to move in the direction close to the second substrate 90 (downward). At this time, the sticking pressure gradually increases, the real-time pressure detected on the sticking head 20 gradually increases, and the pressure difference gradually decreases. When the pressure difference is equal to zero, the sticking head 20 releases the first substrate 80, and the motor 10 drives the sticking head 20 to move in the direction away from the second substrate 90 (upward) to relieve the pressure.

[0090] In addition, when the pressure difference is equal to zero, it can also be maintained for a period of time t. t is the pressure holding time. After the first substrate 80 and the second substrate 90 are pressure-held for t time under the target pressure, the pressure relief action is then carried out.

[0091] In the initial stage of sticking alignment, first set the target pressure when the first substrate 80 and the second substrate 90 are stuck, and measure the real-time pressure received by the sticking head 20 through the pressure detection unit 40. Calculate the pressure difference between the target pressure and the real-time pressure (target pressure - real-time pressure). When the sticking head 20 is running, if the pressure difference does not change, it is considered that the first substrate 80 and the second substrate 90 are not in contact. If the pressure difference changes, it is considered that the first substrate 80 and the second substrate 90 are in contact, and at this time, it directly enters the pressure control mode.

[0092] Please refer to Figure 3 and Figure 4 As shown, in this embodiment, a sticking method is also provided, including the following steps:

[0093] S1: The placement head 20 adsorbs the first substrate 80, and drives the placement head 20 to move vertically downward through the motor 10 to approach the second substrate 90.

[0094] S1-1: Set the target pressure when pasting the first substrate 80 and the second substrate 90. The target pressure can be, for example, 10 N. Detect the real-time pressure received by the placement head 20 through the pressure detection unit 40, and calculate the pressure difference between the target pressure and the real-time pressure (target pressure - real-time pressure).

[0095] When the first substrate 80 and the second substrate 90 are not in contact, set the real-time pressure at this time to zero. Therefore, the pressure difference at this time does not change with the movement of the placement head 20 (or with the movement of the first substrate 80).

[0096] Therefore, if the pressure difference does not change with the movement of the first substrate 80, it is considered that the first substrate 80 and the second substrate 90 are not in contact. When not in contact, it is necessary to make the first substrate 80 quickly approach the second substrate 90 and control the pressure at the moment of contact between the first substrate 80 and the second substrate 90 to prevent overpressure at the moment of contact. Therefore, step S2 is executed at this time.

[0097] If the pressure difference changes with the movement of the first substrate 80, it is considered that the first substrate 80 and the second substrate 90 are in contact. At this time, it is necessary to control the displacement of the first substrate 80 to control the real-time pressure of the first substrate 80 on the second substrate 90, and ensure that the real-time pressure reliably and accurately approaches the target pressure. Therefore, step S3 is executed at this time.

[0098] S2: Measure the real-time distance L from the first substrate 80 to the second substrate 90.

[0099] If the real-time distance L is greater than or equal to the first set distance L1, the controller 60 controls the motor 10 through the positioning control mode, and the motor 10 enters the positioning control mode. In the positioning control mode, the rotation speed of the motor 10 can be set relatively fast, so that it drives the first substrate 80 to quickly move to a position (target position) at a distance of the first set distance L1 from the second substrate 90. In this mode, the target speed can be set so that the first substrate 80 approaches the second substrate 90 at the target speed for most of the time. When approaching the target position quickly, the motor 10 drives the placement head 20 to decelerate, so that when reaching the target position, the output torque of the motor 10 approaches zero (or equals zero), and the speed of the first substrate 80 approaches zero (or equals zero).

[0100] Under normal circumstances, the initial displacement of the placement head 20 is at a relatively large distance from the second substrate 90, such that the initial distance from the first substrate 80 to the second substrate 90 is much greater than the first set distance L1. Therefore, the motor 10 is controlled in a positioning control mode to respond quickly, so that the first substrate 80 runs quickly to a position close to the second substrate 90, thereby reducing the placement time and improving the placement efficiency.

[0101] If the real-time distance L is less than the first set distance L1 and greater than zero, the controller 60 controls the motor 10 in a torque control mode, and the motor enters the torque control mode;

[0102] In the torque control mode, if the real-time distance L is less than the first set distance L1 and greater than the second set distance L2, the output torque of the motor 10 is negatively correlated with the real-time distance L; where the second set distance L2 is less than the first set distance L1; as Figure 4 shown, the torque control mode adopts PID1 control, and its action direction of PID1 can be switched through a switch, and then the control parameters of PID1 are switched to realize the switching between the forward action and the reverse action. When PID1 acts in the forward direction, the output torque of the motor 10 is negatively correlated with the real-time distance L. Then, when the first substrate 80 is closer to the second substrate 90, the output torque of the motor 10 is greater. In this process, on the one hand, the better output characteristics of the motor 10 can be ensured, and on the other hand, the running reliability of the motor 10 is also improved;

[0103] In the torque control mode, if the real-time distance L is less than or equal to the second set distance L2 and greater than zero, the output torque of the motor 10 is positively correlated with the real-time distance L; if the real-time distance L is less than or equal to the second set distance L2, the first substrate 80 exceeds the contact surface corresponding to the second set distance L2, and PID1 performs a reverse action to perform torque control. The output torque of the motor 10 is positively correlated with the real-time distance L; then, when the first substrate 80 is closer to the second substrate 90, the output torque of the motor 10 is smaller, which can well control the overpressure problem at the moment when the first substrate 80 and the second substrate 90 come into contact.

[0104] If the real-time distance L is zero, it means that the first substrate 80 and the second substrate 90 are in contact. At this time, it is necessary to control the placement pressure and execute step S3;

[0105] S3: The controller 60 controls the motor 10 in the pressure control mode. The motor 10 enters the pressure control mode. In this mode, the real-time pressure of the placement head 20 is detected by the pressure detection unit 40, and the pressure difference between the target pressure and the real-time pressure is calculated. When the pressure difference is greater than zero, it means that the placement pressure has not reached the target pressure, and the motor 10 drives the first substrate 80 to move (downward) in the direction close to the second substrate 90 to increase the pressure of the first substrate 80 on the second substrate 90, thereby increasing the real-time pressure.

[0106] When the pressure difference is less than or equal to zero, it means that the placement pressure has reached the target pressure. The placement head 20 releases the first substrate 80, and the motor 10 drives the placement head 20 to move (upward) in the direction away from the second substrate 90 to relieve the pressure, and the placement is completed.

[0107] As Figure 4 shown, in the pressure control mode, PID control is adopted, where the control target is the real-time pressure, so that the real-time pressure gradually approaches the target pressure. Each parameter of PID can be set based on actual control requirements (such as control accuracy requirements).

[0108] In step S2, to ensure that the pressure does not exceed the limit when the first substrate 80 and the second substrate 90 come into contact for the first time, the output torque of the motor 10 in the torque control mode is further limited;

[0109] When the real-time distance L is less than the first set distance L1 and greater than the second set distance L2, the peak value of the output torque of the motor 10 is 0.02 N·m to 0.04 N·m, for example, 0.03 N·m. That is, when PID1 acts positively and the first substrate 80 runs to the second set distance L2, the output torque of the motor 10 is the largest at this time, and the output torque of the motor 10 is 0.02 N·m to 0.04 N·m. By controlling the peak torque of the motor 10, it is possible to prevent the output torque from being too large, resulting in the inertial rotation of the rotor of the motor 10, and further improving the phenomenon of instantaneous overpressure caused by the inertial downward pressure of the first substrate 80 on the second substrate 90, which helps to accurately control the pressure when the first substrate 80 and the second substrate 90 come into contact for the first time.

[0110] When the real-time distance L is less than or equal to the second set distance L2, the minimum value of the output torque of the motor 10 is -0.03 N·m to -0.08 N·m. That is, at the moment when the first substrate 80 comes into contact with the second substrate 90, the torque of the motor 10 is -0.03 N·m to -0.08 N·m, for example, -0.06 N·m.

[0111] When the output torque of the motor 10 is positive, the output torque helps the rotor of the motor 10 to rotate forward, thereby driving the first substrate 80 to move downward (move in the direction close to the second substrate 90); when the output torque of the motor 10 is negative, the output torque prevents the rotor of the motor 10 from rotating forward. At this time, the rotor of the motor 10 may rotate in reverse or decelerate when rotating forward. Therefore, at the moment when the first substrate 80 contacts the second substrate 90, the output torque of the motor 10 is negative, which is essentially used to apply a force to the rotor of the motor 10 to make it rotate in reverse (or prevent it from rotating forward), so that when the first substrate 80 moves downward to contact the second substrate 90, a certain deceleration is obtained, ensuring that the first substrate 80 contacts the second substrate 90 gently or slowly, and then accurately controlling the pressure at the moment of contact between the two.

[0112] In the step S3, when the motor 10 is in the pressure control mode, the output torque of the motor 10 is 0.03 N·m to -0.12 N·m. In this mode, by controlling the output torque of the motor 10, the phenomenon that the motor 10 outputs too large torque and causes the first substrate 80 to move downward due to inertia is prevented, so as to improve the stability of the control of the motor 10. In the pressure control mode, the output torque of the motor 10 can be positive or negative. When the output torque is positive, the output torque drives the motor to rotate forward to increase the real-time pressure; when the output torque is negative, the output torque prevents the motor from rotating forward (at this time, the rotor of the motor rotates in reverse, or the rotor of the motor rotates forward and the rotation speed of the rotor decreases). By controlling the output torque of the motor 10, the motor 10 drives the first substrate 80 to stabilize its controllable movement, and then makes the real-time pressure stable and controllable approach the target pressure. When the real-time pressure is equal to the target pressure and is stabilized (when the difference between the target pressure and the real-time pressure is within the error range, it can be considered that the two are equal and stabilized), after maintaining a certain pasting time, the pasting head 20 relieves pressure, releases the first substrate 80, and the motor 10 drives the pasting head 20 to move upward to complete the pasting.

[0113] It should be noted that the above content gives several implementation manners of the pasting method and the pasting device. The technical features in each implementation manner are not strictly independent, and the technical features in each implementation manner can also be used crosswise.

[0114] In this specification, each embodiment is described in a progressive manner. The key point of each embodiment is to illustrate the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0115] The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention in any way. Any changes and modifications made by those of ordinary skill in the art of the present invention according to the above disclosure are within the protection scope of the claims.

Claims

1. A chip mounting method, characterized in that, It includes the following steps: S1: The placement head adsorbs the first substrate and moves the placement head towards the second substrate by driving of a motor; S2: Measure the real-time distance from the first substrate to the second substrate; If the real-time distance is less than the first set distance and greater than zero, the motor enters the torque control mode; In the torque control mode, if the real-time distance is less than the first set distance and greater than the second set distance, the output torque of the motor is negatively correlated with the real-time distance, and the second set distance is less than the first set distance; if the real-time distance is less than or equal to the second set distance and greater than zero, the output torque of the motor is positively correlated with the real-time distance; If the real-time distance is zero, execute step S3; S3: The motor enters the pressure control mode: In the pressure control mode, detect the real-time pressure of the placement head and calculate the pressure difference between the target pressure and the real-time pressure; when the pressure difference is greater than zero, the motor drives the first substrate to move towards the second substrate to increase the real-time pressure; when the pressure difference is equal to zero, the placement head releases the first substrate, and the motor drives the placement head to move away from the second substrate to relieve the pressure.

2. The chip mounting method according to claim 1, wherein Step S1-1 is further included between step S1 and step S2; S1-1: Detect the real-time pressure of the placement head and calculate the pressure difference between the target pressure and the real-time pressure; If the pressure difference does not change with the movement of the first substrate, it is considered that the first substrate and the second substrate are not in contact, and execute step S2; If the pressure difference changes with the movement of the first substrate, it is considered that the first substrate and the second substrate are in contact, and execute step S3.

3. The chip mounting method according to claim 1, characterized in that In step S2, if the real-time distance is greater than or equal to the first set distance, the motor enters the positioning control mode to drive the first substrate to quickly move to a position where the distance from the second substrate is the first set distance.

4. The chip mounting method according to claim 1, wherein, In step S3, when the motor is in the pressure control mode, the output torque of the motor is 0.03 N·m to -0.12 N·m.

5. The chip mounting method according to claim 1, wherein In step S2, when the real-time distance is less than the first set distance and greater than the second set distance, the peak value of the output torque of the motor is 0.02 N·m to 0.04 N·m.

6. The chip mounting method according to claim 1, wherein, In step S2, if the real-time distance is less than or equal to the second set distance, the minimum value of the output torque of the motor is -0.03 N·m to -0.08 N·m.

7. The chip mounting method according to claim 1, wherein In the torque control mode, the motor adopts PID control; and / or, in the pressure control mode, PID control is adopted.

8. The chip mounting method according to claim 1, characterized in that The motor is a servo motor.

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