Wafer bonding system and bonding wave monitoring method

Abstract

The invention provides a wafer bonding system and a bonding wave monitoring method, and belongs to the technical field of semiconductor equipment, the wafer bonding system comprises an upper chuck and a lower chuck, the two chucks are respectively provided with a plurality of independently adjustable adsorption areas; the ejector pin control system controls the ejector pin to penetrate through the upper chuck in the axial direction of the ejector pin; the adsorption control system is respectively connected with the upper chuck and the lower chuck; the return loss feedback system is connected with one end of the waveguide structure, the other end of the waveguide structure is close to the adsorption surface of the lower wafer, and the return loss feedback system is used for acquiring a deformation signal generated by the lower wafer due to the bonding wave effect; and the central control system is respectively connected with the ejector pin control system, the adsorption control system and the return loss feedback system, and is used for acquiring the propagation morphology of the bonding wave on the lower wafer along with the time change according to the deformation signal, and respectively controlling each system according to the propagation morphology. According to the scheme of the invention, the position of the bonding wave can be accurately obtained, and the fitting accuracy of the propagation morphology of the bonding wave is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor equipment technology, and in particular to a wafer bonding system and a bonding wave monitoring method. Background Art

[0002] As Moore's Law advances to process nodes below 3nm, direct wafer bonding technology is generally considered to be an important technical approach to support three-dimensional chip integration, and has recently become a hot topic of concern for leading semiconductor companies and research institutions at home and abroad. The wafer bonding process usually starts from one point and then gradually spreads to the entire wafer surface, which is also commonly referred to as the diffusion process of the "bonding wave". Affected by different factors such as the wafer surface coating material, circuit design, activation method and parameters, the bonding wave diffusion time may last from several seconds to tens of seconds. The propagation morphology of the bonding wave greatly affects the accuracy and quality of the bonding (such as residual stress distribution, wafer morphology, bonding strength, etc.). Therefore, the industry has been exploring solutions that can monitor the propagation characteristics of the bonding wave in real time, with high sensitivity and practical feasibility.

[0003] In high-precision bonding equipment, a related patent (CN110289222A) has proposed a solution to monitor the bonding wave by arranging a light transmitting and receiving device on the upper chuck and monitoring the bonding wave by the morphological changes of the upper wafer before and after bonding. However, in actual application, this method has the following defects:

[0004] 1) After the ejector pins press down on the upper wafer, each position of the upper wafer deforms to varying degrees. At this time, the signal changes detected by the optical sensor cannot reflect the actual position of the bonding wave (even when the bonding wave has not yet started to propagate, the optical sensor has obvious signals);

[0005] 2) The photosensitive device occupies a large space and requires complex control and circuit layout, so the number that can be arranged on the same chuck is limited. Too discrete data points make it very difficult to accurately fit the bonding wave propagation morphology;

[0006] 3) High cost and difficult to maintain. Summary of the invention

[0007] In view of this, the embodiments of the present application provide a wafer bonding system and a bonding wave monitoring method, which at least partially solve the problem that the bonding wave monitoring method in the prior art has errors in monitoring the actual position of the bonding wave and is high in cost.

[0008] In a first aspect, an embodiment of the present application provides a wafer bonding system, the system comprising:

[0009] An upper chuck and a lower chuck, wherein the upper chuck adsorbs the upper wafer, and the lower chuck adsorbs the lower wafer, and the upper chuck and the lower chuck are respectively provided with a plurality of adsorption areas, and the adsorption capacity of each adsorption area is independently adjustable;

[0010] An ejector and an ejector control system, wherein the ejector passes through the upper chuck along its axial direction, and the ejector control system is used to control the ejector to move along its axial direction;

[0011] An adsorption control system, the adsorption control system is connected to the upper chuck and the lower chuck respectively, and the adsorption control system is used to individually adjust the adsorption capacity of each adsorption area;

[0012] a return loss feedback system, the return loss feedback system being connected to one end of a waveguide structure, the other end of the waveguide structure being close to the adsorption surface of the lower wafer, the waveguide structure being evenly provided with a plurality of return loss feedback systems, and being used to obtain a deformation signal of the lower wafer caused by the bonding wave through the waveguide structure; and

[0013] A central control system, wherein the central control system is respectively connected to the ejector control system, the adsorption control system and the return loss feedback system, and the central control system is used to obtain the time-varying propagation morphology of the bonding wave on the lower wafer according to the deformation signal, and respectively control the adsorption control system and the ejector control system according to the propagation morphology.

[0014] According to a specific implementation of the embodiment of the present application, the waveguide structure is configured as an optical fiber.

[0015] According to a specific implementation of the embodiment of the present application, the optical fiber passes through the lower chuck.

[0016] According to a specific implementation method of an embodiment of the present application, the adsorption surface of the lower chuck is provided with a bump structure, the other end of the optical fiber is located inside the bump structure, and the end face of the other end of the optical fiber is flush with the top of the bump structure.

[0017] According to a specific implementation of the embodiment of the present application, the plurality of optical fibers are laid flat on the adsorption surface of the lower chuck and are led out from the side of the adsorption surface of the lower chuck.

[0018] According to a specific implementation of the embodiment of the present application, the other end of the optical fiber is in contact with the adsorption surface of the lower wafer.

[0019] According to a specific implementation method of the embodiment of the present application, a preset gap is provided between the other end of the optical fiber and the adsorption surface of the lower wafer, and the order of magnitude of the preset gap is the same as the wavelength of the light passing through the optical fiber.

[0020] According to a specific implementation of the embodiment of the present application, the adsorption method of the adsorption area is electrostatic adsorption, negative pressure adsorption or Bernoulli adsorption.

[0021] In a second aspect, an embodiment of the present application further provides a bonding wave monitoring method, which is monitored by using the wafer bonding system as described in any embodiment of the first aspect, and the method includes:

[0022] Adsorbing an upper wafer on the upper chuck, and adsorbing a lower wafer on the lower chuck;

[0023] The ejector control system controls the ejector to apply bonding pressure to the upper wafer, forcing the upper wafer to deform and contact the lower wafer, local bonding occurs at the contact point, and the bonding area gradually diffuses to form a bonding wave diffusion;

[0024] The return loss feedback system acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer caused by the bonding wave according to the signals transmitted by the waveguide structures;

[0025] The central control system acquires the propagation morphology of the bonding wave on the lower wafer that changes with time according to the deformation signal;

[0026] The central control system controls the adsorption control system and the ejector control system respectively according to the propagation morphology.

[0027] According to a specific implementation of the embodiment of the present application, the return loss feedback system acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer due to the bonding wave according to the signals transmitted by the waveguide structure, including:

[0028] arranging the waveguide structure into an optical fiber;

[0029] The return loss feedback system acquires the optical signal transmitted by each optical fiber in real time;

[0030] A light return loss value is calculated according to the optical signal, and the light return loss value is used as the deformation signal.

[0031] Beneficial effects:

[0032] The wafer bonding system and bonding wave monitoring method in the embodiment of the present application can realize accurate real-time feedback of the bonding wave position through the difference in return loss of the waveguide structure to different media and the deformation characteristics of the wafer during the diffusion of the bonding wave. This solution has the following beneficial effects:

[0033] High sensitivity: The return loss of the waveguide structure transmission will only show a jump change when the bonding wave diffuses to the test point, with rapid and sensitive feedback and small error;

[0034] High integration: The waveguide structure has a small diameter and simple circuits. Many measuring points can be arranged on the chuck, which is very easy to integrate and can obtain multiple sets of data points, thus improving the fitting accuracy of the bonding wave propagation morphology.

[0035] Low cost: The waveguide structure and return loss system or instrument are inexpensive, and the cost of each channel is only 30% of that of a displacement sensor or photosensitive device, reducing equipment costs;

[0036] Strong practicability: the test principle is simple and reliable, easy to install and maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 is a structural diagram of a wafer bonding system according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the adsorption area distribution of a chuck according to an embodiment of the present invention;

[0040] Figure 3 (a), (b) and (c) are schematic diagrams of bonding wave diffusion according to an embodiment of the present invention;

[0041] Figure 4 (a), (b) and (c) are schematic diagrams of local deformation of a wafer before and after a bonding wave passes through a certain position according to an embodiment of the present invention;

[0042] Figure 5 (a) and (b) are respectively schematic diagrams of the layout of optical fibers according to an embodiment of the present invention;

[0043] Figure 6 is a top view of a lower chuck according to an embodiment of the present invention;

[0044] Figure 7 for Figure 5 (a) A top view of the lower chuck;

[0045] Figure 8 for Figure 5 (b) Top view of the lower chuck.

[0046] In the figure: 1. First air pressure control system; 2. Central control system; 3. Second air pressure control system; 4. Return loss feedback system; 5. Upper chuck; 6. Negative pressure area; 7. Lower chuck; 8. Optical fiber; 9. Ejector pin; 10. Upper wafer; 11. Lower wafer. DETAILED DESCRIPTION

[0047] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0048] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0049] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0050] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0051] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0052] In a first aspect, the present application provides a wafer bonding system, as shown below: Figures 1 to 8Describe in detail.

[0053] Reference Figure 1 , the wafer bonding system of this embodiment includes the following parts:

[0054] An upper chuck 5 and a lower chuck 7, wherein the upper chuck 5 adsorbs an upper wafer 10, and the lower chuck 7 adsorbs a lower wafer 11, and the upper chuck 5 and the lower chuck 7 are respectively provided with a plurality of adsorption areas, and the adsorption capacity of each adsorption area is independently adjustable;

[0055] An ejector pin 9 and an ejector pin control system, wherein the ejector pin 9 passes through the upper chuck 5 along its axial direction, and the ejector pin control system is used to control the ejector pin 9 to move along its axial direction;

[0056] An adsorption control system, the adsorption control system is connected to the upper chuck 5 and the lower chuck 7 respectively, and the adsorption control system is used to individually adjust the adsorption capacity of each adsorption area;

[0057] A return loss feedback system 4, wherein the return loss feedback system 4 is connected to one end of a waveguide structure, the other end of the waveguide structure is close to the adsorption surface of the lower wafer 11, the waveguide structure is evenly provided with a plurality of return loss feedback systems 4, and the return loss feedback system 4 is used to obtain a deformation signal of the lower wafer 11 due to the bonding wave through the waveguide structure; and

[0058] A central control system 2, wherein the central control system 2 is connected to the ejector control system, the adsorption control system and the return loss feedback system 4 respectively, and the central control system 2 is used to obtain the time-varying propagation morphology of the bonding wave on the lower wafer 11 according to the deformation signal, and control the adsorption control system and the ejector control system respectively according to the propagation morphology.

[0059] In a specific implementation, the adsorption method of the adsorption area is electrostatic adsorption, negative pressure adsorption or Bernoulli adsorption.

[0060] In this embodiment, the adsorption method of the adsorption area is negative pressure adsorption, the adsorption area is a low-pressure cavity, and the corresponding adsorption control system is an air pressure control system, such as Figure 1 As shown, the upper chuck 5 is connected to the first air pressure control system 1, and the lower chuck 7 is connected to the second air pressure control system 3. The specific settings of the chuck and the air pressure control system include: the chucks in the bonding equipment are usually a pair, and the upper chuck 5 can accommodate the ejector pin 9. The chuck surface can be designed with bumps, grooves, pores or other structures, and connected to the air pressure control system to form a negative pressure area 6 between the wafer and the chuck surface, so that the wafer is adsorbed on the chuck surface. The low-pressure cavity of the two chucks can be divided into many independently controllable areas, such as Figure 2As shown, by controlling the air pressure and airflow of these partitions in real time, the adsorption conditions of the upper wafer 10 and the lower wafer 11 can be changed, so as to finely control the diffusion speed of the bonding wave in different directions. The specific bonding process is: the ejector pin 9 in the middle of the upper chuck 5 applies pressure to the upper wafer 10, so that the middle of the upper wafer 10 approaches and contacts the lower wafer 11. During the deformation of the upper wafer 10, the bonding wave moves from the center to the edge of the wafer, and then releases the adsorption vacuum of the upper wafer 10 from the center to the edge in sequence, so that the upper wafer 10 and the lower wafer 11 are bonded under the action of the bonding wave. Therefore, in order to be able to finely control the diffusion speed of the bonding wave in different directions, it is necessary to be able to monitor the current diffusion situation and accurate position of the bonding wave in real time.

[0061] Therefore, the embodiment of the present application can monitor the current diffusion condition and accurate position of the bonding wave in real time by setting a waveguide structure and a return loss feedback system 4 on one side of the adsorption surface of the lower wafer 11, thereby adjusting the adsorption conditions of each low-pressure cavity of the upper wafer 10 and the lower wafer 11 in real time, thereby finely controlling the diffusion speed of the bonding wave in different directions.

[0062] Furthermore, the ejector pin 9 can pass through the upper chuck 5, and the ejector pin 9 can realize force or displacement control through the ejector pin control system, thereby applying pressure to the upper wafer 10, forcing it to deform and contact the lower wafer 11. The contact point realizes bonding under the action of the intermolecular force on the wafer surface, and the bonding area gradually spreads from the point to the surface.

[0063] In one embodiment, the waveguide structure is configured as an optical fiber 8, and the optical fiber 8 is arranged on one side of the lower chuck 7. One end of the optical fiber 8 is in contact with the adsorbed lower wafer 11 or has a small gap (usually at the same order of magnitude as the wavelength of the light passing through the optical fiber 8), and the other end is connected to a return loss feedback system 4 that feeds back the return loss of the optical fiber 8 in real time. The return loss feedback system 4 is a system or instrument that measures the return loss of the optical fiber 8, such as a return loss meter, and feeds back the measurement data in real time. The return loss feedback system 4 transmits the monitoring data of the bonding wave to the central control system 2 in real time. The central control system 2 sends instructions to the air pressure control system and the ejector control system in real time through the control algorithm to adjust the air pressure of each partition of the low-pressure cavity and the pressure and position of the ejector 9, thereby realizing precise control of important characteristics such as the diffusion speed, direction, and morphology of the bonding wave.

[0064] In one embodiment, the optical fiber 8 passes through the lower chuck 7. One end of the optical fiber 8 passes through the lower chuck 7 from the bottom of the lower chuck 7 and contacts the lower wafer 11 or leaves a certain gap, and the other end is located at the lower side of the lower chuck 7 and connected to the return loss feedback system 4, see Figure 1 and Figure 6 As shown. There are small bumps on the chuck, such as Figure 6The circles in the figure are bumps, which are used to make the wafer better adsorbed on the chuck by vacuum. The bumps provide support, and the space between the bumps forms a low-pressure cavity. A circle of sealing steps is also set on the outermost edge. The positions of the small bumps are arranged according to a certain pattern. The figure is only for illustration. Generally, the commonly used ones in the industry are square arrangements with equal spacing, arrangements with equal arc lengths of the circumference, honeycomb arrangements, etc. Figure 6 The solid dots in the figure are the 8 optical fiber points, which are arranged between the convex dots.

[0065] Further, see Figure 5 (b) and Figure 8 The adsorption surface of the lower chuck 7 is provided with a bump structure, the other end of the optical fiber 8 is located inside the bump structure, and the end face of the other end of the optical fiber 8 is flush with the top of the bump structure. In this embodiment, one end of the optical fiber 8 is combined with the bump structure supporting the wafer, that is, these bumps are used as one end of the optical fiber 8 at the same time. This design method can save space, simplify wiring, and is easier to integrate.

[0066] In one embodiment, referring to Figure 5 (a) and Figure 7 The plurality of optical fibers 8 are laid flat on the adsorption surface of the lower chuck 7 and are led out from the side of the adsorption surface of the lower chuck 7 . Figure 7 The circle points with wired connections are the 8 points of optical fiber, and the circles without wire connections are convex point structures.

[0067] In one embodiment, the other end of the optical fiber 8 is in contact with the adsorption surface of the lower wafer 11, or a preset gap is provided between the other end of the optical fiber 8 and the adsorption surface of the lower wafer 11, and the order of magnitude of the preset gap is the same as the wavelength of the light passing through the optical fiber 8.

[0068] It should be noted that Figure 1 and Figure 2 The proportions, sizes, partition arrangements, etc. can be designed differently under different conditions, and those shown in the figure are only examples.

[0069] In a second aspect, an embodiment of the present application further provides a bonding wave monitoring method, which is monitored by using the wafer bonding system as described in any embodiment of the first aspect, and the method includes:

[0070] The upper wafer 10 is adsorbed on the upper chuck 5, and the lower wafer 11 is adsorbed on the lower chuck 7;

[0071] The ejector control system controls the ejector 9 to apply bonding pressure to the upper wafer 10, forcing the upper wafer 10 to deform and contact the lower wafer 11, so that local bonding occurs at the contact point, and the bonding area gradually diffuses to form a bonding wave diffusion;

[0072] The return loss feedback system 4 acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer 11 caused by the bonding wave according to the signals transmitted by the waveguide structures;

[0073] The central control system 2 obtains the propagation morphology of the bonding wave on the lower wafer 11 that changes with time according to the deformation signal;

[0074] The central control system 2 controls the adsorption control system and the ejector control system respectively according to the propagation morphology.

[0075] In one embodiment, the return loss feedback system 4 acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer 11 due to the bonding wave according to the signals transmitted by the waveguide structures, including:

[0076] Arranging the waveguide structure into an optical fiber 8;

[0077] The return loss feedback system 4 acquires the optical signal transmitted by each optical fiber 8 in real time;

[0078] A light return loss value is calculated according to the optical signal, and the light return loss value is used as the deformation signal.

[0079] When implementing it, refer to Figure 3 , the wafer bonding process includes the following steps:

[0080] a) The ejector pins 9 apply pressure to the upper wafer 10, forcing it to deform and contact the lower wafer 11, and local bonding occurs at the contact point;

[0081] b) When the local bonding is triggered, the surfaces of the upper wafer 10 and the lower wafer 11 near the bonded area spontaneously approach each other under the action of the bonding force, so that the bonding area continues to expand, that is, the bonding wave diffusion is formed;

[0082] c) By gradually releasing the negative pressure area 6 of the upper chuck 5, the bonding wave can eventually spread to the entire surface, thereby completing complete wafer-to-wafer bonding.

[0083] The upper wafer 10 will undergo macroscopic deformation under the action of the ejector pin 9. Even when bonding is not triggered, the entire surface of the upper wafer 10 may have undergone displacement and deformation to varying degrees. Therefore, detecting the bonding wave position by monitoring the deformation characteristics of the upper wafer 10 will be interfered with and restricted by many factors (ejector pin pressure, speed, vacuum adsorption conditions, etc.), and it is difficult to be very accurate. Relatively speaking, since the lower wafer 11 is usually adsorbed on the lower chuck 7 on its entire surface during the bonding process, the contact with the surface or contact of the lower chuck 7 is usually relatively stable, and there will be only a small deformation in the short time when the bonding wave passes.

[0084] Reference Figure 4 (a), (b) and (c) respectively show the local deformation of the wafer before, during and after the bonding wave passes through a certain position A. When the bonding wave just diffuses to position A, the lower wafer 11 will slightly detach from the chuck under the action of the bonding force; before and after this, the lower wafer 11 maintains full contact with the lower chuck 7. Assuming that an optical fiber 8 is arranged at position A, light with a wavelength of λ passes through the optical fiber 8, and the top of the optical fiber 8 is parallel to the chuck, according to the Fresnel formula, the return loss RL of the optical fiber 8 is calculated as:

[0085]

[0086] Among them, n1 is the refractive index of the waveguide material used in the optical fiber 8 for light of wavelength λ, and n0 is the refractive index of the medium to which the optical fiber 8 contacts. Assuming that the core is glass, the refractive index for light of wavelength λ is n1 = 1.45. In the states shown in Figures (a) and (c), n0 is the refractive index of silicon, which is about 3.5; and at the moment shown in Figure (b), n0 is the refractive index of air, which is about 1.

[0087] Therefore, in Figure 4 The return loss values ​​of the optical fiber 8 in (a), (b), and (c) are 7.7dB, 14.7dB, and 7.7dB, respectively. Therefore, the moment when the return loss value of this optical fiber 8 changes suddenly is the time when the bonding wave passes through position A. By arranging the optical fiber 8 at different positions of the lower chuck 7 and monitoring the time when the return loss value of each measuring point jumps (the time when the bonding wave passes), the morphological characteristics of the bonded / unbonded areas at different times can be constructed. Therefore, the central control system 2 obtains the propagation morphology of the bonding wave on the lower wafer 11 that changes with time based on the return loss value (deformation signal), and obtains in real time which position the bonding wave is transmitted to in each direction, and then independently controls the adsorption area of ​​the corresponding position of the chuck through the adsorption control system, and controls the applied force of the ejector pin 9, so as to match the timing of the bonding wave transmission with the time of the chuck vacuum control. For example, at a certain moment, the bonding waves at most positions diffuse to a position 100 mm away from the center of the circle, while the bonding waves at the 0 degree position of the circle are only transmitted to a position 90 mm away from the center of the circle. The chuck area corresponding to the 0 degree position will release the vacuum later than other areas.

[0088] The embodiments provided by the present invention have the following differences and advantages compared with the prior art:

[0089] (1) After the ejector pin 9 applies pressure to the upper wafer 10, each position of the upper wafer 10 is deformed to varying degrees. If the photosensitive device in the CN110289222A patent is used to monitor the bonding wave, the signal change monitored by it cannot reflect the actual position of the bonding wave; however, the return loss of the waveguide structure transmission of the embodiment of the present application will only show a jump change when the bonding wave diffuses to the test point, and the feedback is fast and sensitive, with a small error;

[0090] (2) In the embodiment of the present application, the bonding wave position is monitored by the return loss of the optical fiber 8, and there is no need to arrange complex light-emitting and photosensitive devices on the chuck; the optical fiber 8 has a small structure diameter and a simple circuit, and many measuring points can be arranged on the chuck, which is very easy to integrate and can obtain multiple sets of data points, thereby improving the fitting accuracy of the bonding wave propagation morphology;

[0091] (3) Low cost: The waveguide structure and return loss system or instrument are inexpensive, and the cost of each channel is only 30% of the displacement sensor or photosensitive device, reducing equipment costs;

[0092] (4) Strong practicability: The test principle is simple and reliable, easy to install and maintain.

[0093] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A wafer bonding system, characterized in that: The system comprises: An upper chuck (5) and a lower chuck (7), wherein the upper chuck (5) adsorbs an upper wafer (10), and the lower chuck (7) adsorbs a lower wafer (11), and the upper chuck (5) and the lower chuck (7) are respectively provided with a plurality of adsorption areas, and the adsorption capacity of each adsorption area is independently adjustable; An ejector pin (9) and an ejector pin control system, wherein the ejector pin (9) passes through the upper chuck along its axial direction, and the ejector pin control system is used to control the ejector pin (9) to move along its axial direction; An adsorption control system, the adsorption control system being connected to the upper chuck (5) and the lower chuck (7) respectively, and the adsorption control system being used to individually adjust the adsorption capacity of each of the adsorption areas; A return loss feedback system (4), the return loss feedback system (4) being connected to one end of a waveguide structure, the other end of the waveguide structure being close to the adsorption surface of the lower wafer (11), the waveguide structure being evenly provided with a plurality of return loss feedback systems (4), and being used to obtain a deformation signal of the lower wafer (11) generated by the bonding wave through the waveguide structure; and A central control system (2), the central control system (2) being connected to the ejector control system, the adsorption control system and the return loss feedback system (4) respectively, the central control system (2) being used to obtain the time-varying propagation morphology of the bonding wave on the lower wafer (11) according to the deformation signal, and to control the adsorption control system and the ejector control system respectively according to the propagation morphology.

2. The wafer bonding system according to claim 1, characterized in that: The waveguide structure is configured as an optical fiber (8).

3. The wafer bonding system according to claim 2, characterized in that: The optical fiber (8) passes through the lower chuck (7).

4. The wafer bonding system according to claim 3, characterized in that: The adsorption surface of the lower chuck (7) is provided with a convex structure, the other end of the optical fiber (8) is located inside the convex structure, and the end surface of the other end of the optical fiber (8) is flush with the top of the convex structure.

5. The wafer bonding system according to claim 2, characterized in that: The plurality of optical fibers (8) are laid flat on the adsorption surface of the lower chuck (7) and are led out from the side of the adsorption surface of the lower chuck (7).

6. The wafer bonding system according to claim 2, characterized in that: The other end of the optical fiber (8) is in contact with the adsorption surface of the lower wafer (11).

7. The wafer bonding system according to claim 2, characterized in that: A preset gap is provided between the other end of the optical fiber (8) and the adsorption surface of the lower wafer (11), and the order of magnitude of the preset gap is the same as the wavelength of the light passing through the optical fiber (8).

8. The wafer bonding system according to claim 1, characterized in that: The adsorption method of the adsorption area is electrostatic adsorption, negative pressure adsorption or Bernoulli adsorption.

9. A bonding wave monitoring method, using the wafer bonding system according to any one of claims 1 to 8 for monitoring, characterized in that: The method comprises: An upper wafer (10) is adsorbed onto the upper chuck (5), and a lower wafer (11) is adsorbed onto the lower chuck (7); The ejector control system controls the ejector (9) to apply bonding pressure to the upper wafer (10), forcing the upper wafer (10) to deform and contact the lower wafer (11), causing local bonding at the contact point, and the bonding area gradually diffuses to form a bonding wave diffusion; The return loss feedback system (4) acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer (11) caused by the bonding wave according to the signals transmitted by the waveguide structures; The central control system (2) acquires the propagation morphology of the bonding wave on the lower wafer (11) that changes with time according to the deformation signal; The central control system (2) controls the adsorption control system and the ejector control system respectively according to the propagation morphology.

10. The bonding wave monitoring method according to claim 9, characterized in that: The return loss feedback system (4) acquires the signals transmitted by each of the waveguide structures in real time, and generates a deformation signal of the lower wafer (11) due to the bonding wave according to the signals transmitted by the waveguide structures, including: The waveguide structure is arranged as an optical fiber (8); The return loss feedback system (4) acquires the optical signal transmitted by each optical fiber (8) in real time; A light return loss value is calculated according to the optical signal, and the light return loss value is used as the deformation signal.

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