Wafer bonding equipment and wafer bonding method based on bifocal imaging

Abstract

The invention discloses wafer bonding equipment and a wafer bonding method based on bifocal imaging, and belongs to the field of bonding processing equipment. The wafer bonding equipment comprises a bearing table, a bonding assembly, a first displacement mechanism and a second displacement mechanism, a calibration plate, a first visual assembly and a second visual assembly are arranged corresponding to the alignment of a to-be-pasted chip and a target chip, and by means of the arrangement of paired detection light with equal focusing optical paths in the visual assemblies and the arrangement of the optical path difference of two optical paths in the visual assemblies, the two visual assemblies can achieve focusing imaging of calibration Marks and detection Marks on the two chips respectively. In this way, the relative positions of the two detection Marks are obtained, position compensation information needed when the two chips are accurately aligned is obtained, and finally accurate alignment of the two chips before bonding is achieved. The wafer bonding equipment is compact in structure and convenient to use, the alignment precision of the to-be-bonded chip and the target chip before bonding can be ensured, the quality of chip bonding processing is improved, and the reject ratio of chip processing is reduced.

Description

Technical Field

[0001] The invention belongs to the field of bonding processing equipment, and in particular relates to a wafer bonding equipment and a wafer bonding method based on dual-focus imaging. Background Art

[0002] Hybrid bonding technology is a new type of semiconductor packaging technology that uses intermolecular forces, metal diffusion, eutectic welding and other mechanisms to achieve high-strength and high-reliability bonding between layers. It can integrate homogeneous or heterogeneous materials and achieve vertical stacking, facilitating the development of three-dimensional integrated circuits (3D-ICs).

[0003] Compared with traditional packaging technology, hybrid bonding without bumps can achieve higher density integration and significantly reduce chip power consumption, and has extremely promising application prospects in many fields.

[0004] In general, the hybrid bonding process can be divided into three process stages: surface treatment, alignment bonding, and post-processing. Among them, the surface treatment process uses plasma or acid and alkali to clean and activate the surface of the chip and wafer to enhance adhesion. Alignment bonding is to complete the high-precision alignment of the chip and the wafer to ensure that the pads correspond one by one, and then directly bond through van der Waals forces, the forces between molecules and atoms under a certain pressure. The post-processing process is to strengthen the bonding through annealing, and the annealing temperature is usually between 200 and 300 ° C. In the entire process flow, alignment accuracy is a key indicator that affects the electrical connection and reliability of the chip. Once there is a problem with the alignment accuracy, it will greatly affect the yield and cause huge losses. Therefore, how to accurately and effectively realize the alignment operation in the bonding process has become the focus of researchers, and it is also the first problem to be solved when wanting to improve the efficiency and yield of hybrid bonding processing. Summary of the invention

[0005] In response to one or more of the above defects or improvement needs in the prior art, the present invention provides a wafer bonding device and a wafer bonding method based on dual-focus imaging, which can accurately achieve accurate alignment of the chip to be bonded and the target chip before bonding, reduce the error of chip bonding, and improve the quality of chip bonding processing.

[0006] To achieve the above object, one aspect of the present invention provides a wafer bonding device based on dual-focus imaging, comprising: A carrier platform, used for carrying the target chip; A bonding assembly, the bonding assembly comprising a bonding head and a plane adjustment module; the bonding head is used for picking up and pressing down the chip to be bonded, and is connected to the plane adjustment module, and the plane adjustment module can be used to perform XYθ adjustment within the plane; A first displacement mechanism and a second displacement mechanism are assembled and connected to each other; the first displacement mechanism is a horizontal displacement mechanism, used to drive the second displacement mechanism to perform horizontal displacement in a first direction; the bonding assembly is connected to the second displacement mechanism, so that the bonding head can be driven by the second displacement mechanism to perform lifting and lowering displacement in a second direction to approach or move away from the bearing platform; A calibration plate, which is arranged on one side of the bonding head along the first direction, is made of a transparent material, and has a calibration mark on its top surface or bottom surface; A first visual component, wherein the light outlet of the first visual component is used to simultaneously output a first optical path and a second optical path that are parallel to each other, the focusing optical paths of the two optical paths are equal, and a first optical path difference is formed in the first visual component; the first optical path difference is equal to the spacing between a second detection Mark and a calibration Mark on the target chip in the exit directions of the two optical paths, and the optical path of the first optical path in the visual component is smaller than the optical path of the second optical path in the visual component; the first optical path can be focused and imaged when irradiated on the second detection Mark, and the second optical path can be focused and imaged when irradiated on the calibration Mark; A second visual component, wherein the light outlet of the second visual component is used to simultaneously output a third optical path and a fourth optical path which are parallel to each other and have equal focusing optical paths; wherein the optical path of the third optical path in the visual component is smaller than the optical path of the fourth optical path in the visual component, and the second optical path difference between the two optical paths in the visual component is equal to the spacing between the first detection mark and the calibration mark of the chip to be attached on the bonding head in the emission directions of the two optical paths, so that when the bonding component is aligned with the second visual component, the third optical path can focus on the calibration mark and the fourth optical path can focus on the first detection mark at the same time; The second visual component is used to obtain the relative position coordinates of the first detection Mark and the calibration Mark, and the second visual component is used to obtain the relative position coordinates of the second detection Mark and the calibration Mark, and the relative position coordinates between the two detection Marks are converted; according to the relative position coordinates, the plane adjustment module is controlled to adjust the position of the chip to be mounted, so as to achieve accurate alignment of the two chips before bonding.

[0007] As a further improvement of the present invention, the material taking position of the chip to be mounted, the carrying platform, and the second visual component are arranged at intervals in the first direction, and the second visual component is arranged between the material taking position and the carrying platform.

[0008] As a further improvement of the present invention, at least one visual component includes a camera module and a reflector group; The camera module is used to output a pair of parallel detection lights and form two optical paths with equal focusing optical paths. The reflector group is arranged corresponding to the light outlet of the visual component, and includes a first reflector and a second reflector arranged side by side in the spacing direction of the two optical paths; and the first reflector protrudes more than the second reflector in the direction of the two optical paths, and the protruding distance of the first reflector is equal to the optical path difference between the two optical paths in the visual component.

[0009] As a further improvement of the present invention, the camera module is directly arranged on one side of the reflector group, and the camera module directly directs the two generated parallel light paths toward the reflector group; or At least one reversing mirror is arranged between the camera module and the reflector group for controlling the reversing of two parallel light paths.

[0010] As a further improvement of the present invention, the optical path directions of the two detection lights emitted by the camera module are parallel to the optical path directions emitted from the light outlet of the visual component, and a first reversing mirror and a second reversing mirror are arranged between the camera module and the reflector group; The first deflection mirror is arranged corresponding to the camera module, and is used to deflect the detection light transmitted along the second direction to be transmitted horizontally; the second deflection mirror is arranged between the reflector group and the first deflection mirror, and is used to deflect the two detection lights to a horizontal direction perpendicular to the first direction.

[0011] As a further improvement of the present invention, the first displacement mechanism includes a translation guide rail extending along the first direction and a translation motor mounted on the translation guide rail, and the translation motor can reciprocate along the first direction on the translation guide rail; The second displacement mechanism includes a lifting guide rail extending along the second direction and a lifting motor mounted on the lifting guide rail; the lifting guide rail is connected to the translation motor and can follow the translation motor to perform reciprocating translation in the first direction; the lifting motor is mounted on the lifting guide rail and can move back and forth along the second direction on the lifting guide rail; and the plane adjustment module is connected to the lifting motor and can follow the lifting motor to move back and forth in the second direction.

[0012] As a further improvement of the present invention, the first displacement mechanism also includes a fixed plate fixedly connected to the translation motor; and the lifting guide rail and the first visual component are fixedly mounted on the fixed plate at the same time, and can reciprocate and translate following the fixed plate.

[0013] As a further improvement of the present invention, a translation component is provided on the fixed plate corresponding to the first visual component or the lifting guide rail; The first visual component or the lifting guide rail is mounted on the fixed plate via a translation component, and the relative position of the first visual component and the lifting guide rail in the first direction can be adjusted by control of the translation component.

[0014] As a further improvement of the present invention, the internal components of the two visual components are composed of the same; the light paths emitted from the light outlets of the two visual components are parallel and in opposite directions.

[0015] Another aspect of the present invention further provides a wafer bonding method based on dual-focus imaging, which utilizes the wafer bonding device based on dual-focus imaging and includes the following process: (1) The bonding head completes the material collection of the chip to be bonded; (2) Controlling the movement of the first displacement mechanism to drive the bonding head to the second visual component, so that the third optical path and the fourth optical path are focused and imaged at the calibration mark and the first detection mark respectively, and obtaining the coordinate information of the first detection mark relative to the calibration mark; (3) Controlling the first visual component to align with the second detection Mark, completing the focus imaging of the second detection Mark through the first optical path, and obtaining the coordinate information of the second detection Mark; (4) Control the bonding head to translate, align the calibration plate with the first visual component, complete the focus imaging of the calibration mark through the second optical path, obtain another coordinate information of the calibration mark, and obtain the coordinate information of the second detection mark relative to the calibration mark based on this; (5) Obtain the relative position coordinates between the two detection marks based on the coordinate information of the first detection mark relative to the calibration mark and the coordinate information of the second detection mark relative to the calibration mark, and thereby obtain the compensation position coordinates of the chip to be mounted that needs to be displaced when the two chips are aligned; (6) Controlling the plane adjustment module to work according to the compensation position coordinates to accurately align the chip to be bonded with the target chip; thereafter, controlling the second displacement mechanism to work, and driving the bonding head to press the chip to be bonded downward to complete bonding with the target chip.

[0016] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0017] In general, compared with the prior art, the above technical solution conceived by the present invention has the following beneficial effects: (1) The wafer bonding equipment based on dual-focus imaging of the present invention comprises a carrier, a bonding component and a first displacement mechanism and a second displacement mechanism arranged corresponding to the bonding component. By arranging a calibration plate, a first visual component and a second visual component corresponding to the alignment of a chip to be bonded and a target chip, and utilizing the setting of paired detection lights with equal focusing optical paths in the visual component and the setting of the optical path difference between two optical paths in the visual component, the two visual components can respectively realize the focusing imaging of the calibration mark and the detection mark on the two chips, thereby realizing the acquisition of the relative positions of the two detection marks, and further obtaining the position compensation information required for the accurate alignment of the two chips, and finally realizing the accurate alignment of the two chips before bonding, thereby improving the efficiency and accuracy of the alignment and bonding of the chip to be bonded and the target chip, and reducing the defect rate of the chip bonding process.

[0018] (2) The wafer bonding method based on dual-focus imaging of the present invention is implemented by using a wafer bonding device with an optimal design, has simple steps and convenient control, and can utilize the mechanism of dual-focus imaging to accurately realize the alignment process of the chip to be attached and the target chip before bonding, thereby improving the efficiency of chip alignment and wafer bonding and reducing the cost of chip bonding processing.

[0019] (3) The wafer bonding equipment based on dual-focus imaging in the present invention has a compact structure and is easy to use. It can realize the imaging of the detection marks on the two chips and the calibration marks on the calibration plate based on the dual-focus imaging principle, accurately obtain the relative position coordinates between the two detection marks on the two chips, and thereby obtain the compensation position coordinates required for the alignment between the two chips, thereby ensuring the alignment accuracy between the chip to be bonded and the target chip before bonding, improving the quality of chip bonding processing, and reducing the defective rate of chip processing. It has good practical value and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, 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 invention. For those skilled in the art, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 is a schematic diagram of the overall structure of a wafer bonding device based on dual-focus imaging in an embodiment of the present invention; Figure 2 is a side view of the internal component arrangement of the first visual assembly in an embodiment of the present invention; Figure 3 is a top view of the internal component arrangement of the first visual assembly in an embodiment of the present invention; Figure 4 is a schematic diagram of focusing a target chip using a first visual component in an embodiment of the present invention; Figure 5 is a schematic diagram of focusing a calibration plate using a first visual component in an embodiment of the present invention; Figure 6 is a schematic diagram of a dual-focusing operation performed using a second visual component in an embodiment of the present invention; In all the drawings, the same reference numerals represent the same technical features, specifically: 1. Bonding assembly; 2. Calibration board; 3. First displacement mechanism; 4. Second displacement mechanism; 5. First visual assembly; 6. Second visual assembly; 7. Chip to be bonded; 8. Target chip; 9. Wafer; 10. Carrier; 101. bonding head; 102. plane adjustment module; 301, translation guide rail; 302, translation motor; 401, lifting guide rail; 402, lifting motor; 501, camera; 502, lens; 503, first reversing mirror; 504, second reversing mirror; 505, reflector assembly; 5051, first reflector; 5052, second reflector. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0023] In the description of the present invention, it should be understood that, unless otherwise expressly specified and limited, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] Example: The wafer bonding device based on dual-focus imaging of the present invention is intended to achieve accurate alignment between the chip to be bonded 7 and the target chip 8 before chip bonding, thereby ensuring the accuracy and reliability of chip bonding.

[0028] It should be noted that when the bonding equipment performs bonding operations, the bonding component 1 needs to undergo at least two processes: material picking (picking up the chip to be bonded 7) and displacement (the chip to be bonded 7 moves from the material picking position to the top of the target chip 8), and both processes are completed under precise control.

[0029] That is to say, when the bonding head 101 is picking up the chip 7 to be bonded, the chip 7 to be bonded and the bonding head 101 in the bonding assembly 1 have a relatively accurate alignment relationship, and there will not be a situation where the deviation between the two is too large. At the same time, after moving to the top of the target chip 8, there will not be a situation where there is an obvious misalignment between the two chips.

[0030] In short, the wafer bonding equipment in the preferred embodiment is intended to achieve precise alignment of two chips to be bonded under a certain alignment accuracy. By setting corresponding components, the slight errors introduced by the mechanical movement of the equipment are compensated, thereby ensuring sufficient alignment of the two chips before bonding and improving the quality of chip bonding.

[0031] Specifically, the wafer bonding equipment in the preferred embodiment is as follows: Figure 1 to Figure 6 As shown in , it includes a bonding component 1, a first visual component 5, a second visual component 6 and a carrier 10, and a first displacement mechanism 3 and a second displacement mechanism 4 are provided corresponding to the motion control of the bonding component 1.

[0032] Among them, taking the diagram as an example, the first displacement mechanism 3 in the preferred embodiment is an X-axis displacement mechanism, which is used to drive the second displacement mechanism 4 and the bonding component 1 to perform horizontal displacement in the first direction (i.e., the X-axis direction in the diagram), and through the control of the first displacement mechanism 3, the processes of taking the chip 7 to be attached, aligning with the second visual component 6, and aligning with the target chip 8 are completed.

[0033] At the same time, the second displacement mechanism 4 in the preferred embodiment is the Z-axis displacement mechanism shown in the figure, which is used to drive the bonding component 1 to move back and forth in the second direction (i.e., the Z-axis direction in the figure), and complete the step bonding process of the chip 7 to be attached through the control of the second displacement mechanism 4.

[0034] It should be noted that Figure 1 to Figure 6 The triangle coordinate system in the coordinate system legend indicates that the direction of the corresponding coordinate is perpendicular to the paper surface and inward, for example Figure 1 The Y axis in Figure 2 The X-axis in the figure; and the "" in the legend indicates that the direction of the corresponding coordinate is perpendicular to the paper and outward, for example Figure 3 The Z axis in .

[0035] In more detail, the bonding assembly 1 in the preferred embodiment includes a bonding head 101 , which is connected to a plane adjustment module 102 , so that the bonding head 101 can be adjusted in the XYθ direction in a horizontal plane driven by the plane adjustment module 102 .

[0036] By using the setting of the plane adjustment module 102, the plane position of the bonding head 101 can be adjusted after visual inspection, so as to achieve accurate alignment between the chip to be bonded 7 and the target chip 8 before bonding.

[0037] In more detail, in a preferred embodiment, the bottom surface of the bonding head 101 is a working surface, and a plurality of adsorption holes are provided on the working surface for adsorbing and bonding the chip 7 to be bonded onto the bonding head 101 .

[0038] At the same time, the first displacement mechanism 3 and the second displacement mechanism 4 are combined to control the displacement of the corresponding bonding assembly 1. The plane adjustment module 102 of the bonding assembly 1 is connected to the second displacement mechanism 4, and can be driven by the second displacement mechanism 4 to move back and forth, close to or away from the carrier 10.

[0039] exist Figure 1 In the preferred embodiment shown, the second displacement mechanism 4 is a lifting displacement mechanism, that is, a Z-axis displacement mechanism, which can drive the bonding component 1 to perform lifting and reciprocating motion, approaching or moving away from the carrier 10 in the Z-axis direction (vertical direction), and finally complete the downward bonding process after the chip to be bonded 7 is aligned with the target chip 8.

[0040] At the same time, the first displacement mechanism 3 in the preferred embodiment is a horizontal displacement mechanism, and the second displacement mechanism 4 is assembled on the first displacement mechanism 3. Through the control of the first displacement mechanism 3, the displacement control of the second displacement mechanism 4 and the bonding component 1 connected to the second displacement mechanism 4 in the horizontal direction can be realized.

[0041] exist Figure 1 In the preferred embodiment shown, the first displacement mechanism 3 is an X-axis displacement mechanism, which can be reciprocated in the X-axis direction. At the same time, in the preferred embodiment, the material picking station of the chip to be mounted 7 and the carrier 10 are arranged at intervals in the X-axis direction, so that the bonding assembly 1 can switch between the material picking station and the bonding station by horizontal displacement.

[0042] Exemplarily, the two displacement mechanisms in the preferred embodiment preferably both include guide rails and motors mounted on the respective guide rails, and reciprocating displacement in corresponding directions is achieved by controlling the motors and guiding the guide rails.

[0043] For example, the first displacement mechanism 3 includes a translation guide rail 301 and a translation motor 302; the second displacement mechanism 4 includes a lifting guide rail 401 and a lifting motor 402. The lifting guide rail 401 is preferably connected to the translation motor 302, so that the lifting guide rail 401 can follow the translation motor 302 to perform horizontal reciprocating displacement. Correspondingly, the plane adjustment module 102 is connected to the lifting motor 402 and can follow the lifting motor 402 to perform vertical lifting displacement.

[0044] Furthermore, corresponding to the pre-bonding alignment of the chip to be attached 7 and the target chip 8 on the bonding head 101, a first visual component 5 and a second visual component 6 are also provided accordingly. By utilizing the setting and use of the two visual components, the position detection of the chip to be attached 7 and the target chip 8 can be accurately achieved, and finally the accurate alignment of the two chips before bonding is completed.

[0045] In actual setting, the setting structures of the two visual components in the preferred embodiment are preferably equal, and the shooting directions of the two visual components are opposite, and the detection direction of the first visual component 5 is downward, which is used for position detection of the target chip 8. Correspondingly, the detection direction of the second visual component 6 is upward, which is used for position detection of the chip to be attached 7.

[0046] In order to ensure that the position detection of the two chips has the same reference and target, a calibration plate 2 is preferably provided on one side of the bonding head 101. The calibration plate 2 is made of a transparent material and has calibration marks on its top or bottom surface that can be focused and photographed by two visual components.

[0047] Exemplarily, the calibration plate 2 in the preferred embodiment is transparent glass or glass with an anti-reflection film coated on the surface.

[0048] In a preferred embodiment, the calibration mark is set on the bottom surface of the calibration plate 2, which will be further described later. Of course, if the calibration mark is set on the top surface of the calibration plate 2, the arrangement of the two visual components can be adjusted accordingly, which will not be described in detail here.

[0049] At the same time, corresponding focus marks are respectively set on the end faces of the two chips facing each other, namely, the first detection mark set on the bottom surface of the chip to be mounted 7 and the second detection mark set on the top surface of the target chip 8. By obtaining the relative positions of at least two groups of detection marks, the relative positions of the two chips can be obtained accordingly, and accurate position compensation information can be provided for the adjustment action of the plane adjustment module 102, thereby driving the chip to be mounted 7 to complete the corresponding position adjustment.

[0050] Combined with the above records, it can be understood that after the material picking and displacement control of the chip to be attached 7 are actually completed, a certain alignment relationship is satisfied between the chip to be attached 7 and the target chip 8. After the alignment detection of the two chips is completed, only a small adjustment of the XYθ in the plane is required to achieve complete alignment between the two chips.

[0051] Furthermore, the first visual component 5 of the preferred embodiment is arranged on the side of the bonding component 1 provided with the calibration plate 2, and the field of view of its light outlet faces downward, and can emit a pair of mutually parallel detection light paths (i.e. Figure 2 In the optical path A and optical path B, the focusing optical paths of the two detection optical paths are equal.

[0052] At the same time, the optical paths of the two detection light paths inside the first visual component 5 have a certain optical path difference. The two detection light paths are respectively the first optical path and the second optical path. The optical path of the first optical path in the visual component is smaller than the optical path of the second optical path, and the optical path difference between the two optical paths is W1.

[0053] In more detail, the optical path difference W1 between the first optical path and the second optical path is equal to the distance between the calibration mark on the calibration plate 2 and the second detection mark on the target chip 8 in the axial direction of the outgoing optical path, that is, the distance between the calibration mark and the second detection mark in the axial direction of the outgoing optical path. Figure 1 The spacing along the Z axis.

[0054] By such arrangement, two detection light paths with an optical path difference in the first visual component 5 can be focused and imaged at the calibration mark and the second detection mark respectively.

[0055] Obviously, after the light exits from the first visual component 5, the second light path ( Figure 5 The optical path of the first optical path ( Figure 5 This part of the optical path difference is exactly equal to the optical path of the second optical path being greater than the optical path of the first optical path in the visual component, that is, W1.

[0056] In actual settings, two detection light paths with a certain optical path difference are obtained through offset mirrors in the visual component, for example Figure 2 The first reflector 5051 and the second reflector 5052 in the visual component. The two reflectors are arranged at the light outlet of the visual component, and the reflective surface thereof is arranged at an acute angle with the axis of the light outlet, so as to reflect the detection light path from the camera module and output it. At the same time, the two reflectors are arranged side by side in the spacing direction of the two detection light paths, that is, the reflection parts of the two reflectors are in the same plane as the two detection light paths. Moreover, in the direction of the detection light path, the position of the first reflector 5051 is closer to the front than the position of the second reflector 5052, so that the first reflector 5051 reflects the first light path earlier than the second reflector 5052, creating an optical path difference between the two detection light paths in the visual component. In more detail, the spacing between the two reflectors in the direction of the detection light path is exactly W1.

[0057] Such an arrangement enables the first reflector 5051 to reflect one of the two parallel optical paths of the second reflector 5052 , that is, the optical path of the detection light path reflected from the first reflector 5051 is shorter in the visual component than the optical path of the detection light path reflected from the second reflector 5052 .

[0058] For example, in Figure 2 , Figure 3 In the preferred embodiment shown, the detection light path directed to the two reflectors extends along the Y-axis, and the first reflector 5051 protrudes beyond the second reflector 5052 in the Y-axis direction, and the protruding distance is exactly equal to W1. In this way, the originally parallel two beams of detection light will be reflected by the two reflectors in succession.

[0059] Furthermore, the two reflectors are arranged at an offset interval in the displacement direction of the first displacement mechanism 3 , so that the two detection light paths output after being reflected from the two reflectors are arranged at an offset interval in the displacement direction of the first displacement mechanism 3 .

[0060] It is not difficult to understand that the two detection light paths output after reflection from the two reflectors are spaced apart by a certain distance in the Y-axis direction and also spaced apart by a certain distance in the X-axis direction.

[0061] More preferably, in actual setting, the two detection light paths of the two reflective mirrors of the camera can come directly from the camera module or from a synchronous reversing mirror group arranged corresponding to the camera module.

[0062] For example, in Figure 2 , Figure 3 In the preferred embodiment shown, the camera module and the reflector group 505 are arranged in a staggered manner in space. The camera module includes a camera 501 and a lens 502, and at least one reversing mirror is arranged corresponding to the two detection light paths emitted simultaneously from the lens 502, for example Figure 3 The first reversing mirror 503 and the second reversing mirror 504 are used to convert the vertical light path emitted by the camera module into a horizontal light path, and the latter is used to achieve the angle conversion of the horizontal light path in the plane.

[0063] It can be understood that in the above embodiment, the camera module can also be set at the position of the first reversing mirror 503 to send two synchronous detection light paths to the second reversing mirror 504. In this case, the number of reversing mirrors set is one.

[0064] In addition, in the above embodiment, if the camera module is arranged at the position of the second reversing mirror 504 , then the reversing mirror is not arranged, and the reflecting mirror group 505 directly reflects the two parallel detection light paths emitted synchronously.

[0065] In more detail, the second reflector 5052 in the preferred embodiment is arranged on the side of the first reflector 5051 facing away from the bonding component 1, and when the two chips are aligned with each other, the axis of the first light path of the first reflector 5051 passes through the second detection mark on the target chip 8, and the axis of the second light path of the second reflector 5052 passes through the calibration mark on the calibration plate 2.

[0066] In a preferred embodiment, the setting position of the first visual component 5 can be relatively fixed, and the alignment of different target chips 8 on the wafer 9 and the first visual component 5 is achieved by controlling the displacement of the wafer 9 on the carrier 10, ensuring that the axis of the first optical path always passes through the second detection mark. At this time, the bonding component 1 realizes displacement movement relative to the first visual component 5 driven by the two displacement mechanisms.

[0067] In another preferred embodiment, the first visual component 5 is preferably disposed on a displacement mechanism and can be adjusted relative to the supporting platform 10 .

[0068] More preferably, the first visual component 5 is preferably assembled and connected to the first displacement mechanism 3, for example, fixedly connected to the translation motor 302, and at this time, the first visual component 5 can follow the second displacement mechanism 4 and the bonded component 1 connected to the second displacement mechanism 4 to perform synchronous horizontal displacement. Accordingly, the relative displacement between the bonded component 1 and the first visual component 5 can be achieved by the plane adjustment module 102 or a displacement mechanism separately provided for the corresponding bonded component 1.

[0069] For example, in a specific preferred embodiment, the first displacement mechanism 3 includes a fixed plate, which is fixedly connected to the translation motor 302 and can be reciprocated following the translation motor 302. Correspondingly, the second displacement mechanism 4 and the first visual component 5 are preferably arranged on the fixed plate, and the displacement of the fixed plate drives the first visual component 5 and the bonding component 1 to be synchronously displaced and adjusted relative to the carrier 10. At this time, the relative displacement between the first visual component 5 and the bonding head 101 can be achieved according to the control of the plane adjustment module 102.

[0070] In more detail, in another specific preferred embodiment, the function of the plane adjustment module 102 is to adjust the compensation position information without large-scale translation adjustment. At this time, the first visual component 5 or the lifting guide rail 401 is preferably installed on the fixed plate through the translation component, and the relative position of the first visual component 5 and the second displacement mechanism 4 in the first direction can be adjusted by the control of the translation component. With such a configuration, the control process of the bonding head 101 away from or blocking the first optical path can be more conveniently realized, such as Figure 5 , Figure 6 The switching process of the state.

[0071] Furthermore, the setting mechanism of the second visual component 6 in the preferred embodiment is similar to the setting mechanism of the first visual component 5, and it can also generate two parallel detection light paths, and the directions of the two detection light paths emitted by the second visual component 6 are opposite to the directions of the two detection light paths emitted by the first visual component 5.

[0072] For example, in Figure 1 In the preferred embodiment shown, the detection light path emitted by the first vision component 5 is along the negative direction of the Z axis, and the detection light path emitted by the second vision component 6 is along the positive direction of the Z axis.

[0073] In more detail, the structural composition of the second visual component 6 is preferably the same as that of the first visual component 5, and the two detection light paths outputted from the light outlet are respectively the third light path and the fourth light path, the focusing optical paths of the two light paths are equal, and the optical path of the third light path in the visual component is smaller than the optical path of the fourth light path in the visual component, that is, the distance between the focus point of the third light path and the light outlet of the visual component is larger than the distance between the focus point of the fourth light path and the light outlet, such as Figure 4 As shown in (the left dotted line in the figure is the third light path, and the right dotted line is the fourth light path).

[0074] More specifically, in the second visual component 6, the optical path difference W2 between the third optical path and the fourth optical path is equal to the distance between the calibration Mark and the first detection Mark in the axial direction of the optical path, that is, Figure 1 The distance between the two marks in the Z-axis direction.

[0075] Exemplarily, in a specific preferred embodiment, the bottom surface of the calibration plate 2 is flush with the bottom surface of the bonding head 101, and the calibration mark is set on the bottom surface of the calibration plate 2. At this time, the distance between the calibration mark and the first detection mark on the optical axis is just equal to the thickness of the chip 7 to be mounted.

[0076] In actual setting, the bottom surface of the calibration plate 2 does not protrude from the bottom surface of the chip 7 to be bonded after the bonding head 101 takes the material. It is further preferably not protruding from the bottom surface of the bonding head 101 to reduce the impact of the calibration plate 2 on the bonding of the chip 7 to be bonded.

[0077] By setting two detection light paths in the second visual component 6, after the light outlet of the second visual component 6 is vertically aligned with the bonding component 1, the third light path can be focused on the calibration mark of the calibration plate 2, and the fourth light path can be focused on the first detection mark of the chip to be mounted 7.

[0078] Preferably, in actual setting, the second visual component 6 is arranged between the material picking position of the chip to be attached 7 and the supporting platform 10, and the connecting line of the three is preferably parallel to the displacement direction of the first displacement mechanism 3, so that the bonding component 1 can be switched between the material picking position of the chip to be attached 7, the second visual component 6, and the supporting platform 10 under the drive of the first displacement mechanism 3.

[0079] In more detail, considering that the second visual component 6 can be arranged in the same manner as the first visual component 5, in the second visual component 6, the optical path difference between the two detection light paths can also be controlled by arranging a pair of reflector groups.

[0080] by Figure 1Take the preferred embodiment shown in as an example, at this time, the reflector corresponding to the third optical path protrudes from the reflector of the fourth optical path in the Y-axis direction, and the protruding distance is just equal to W2. At the same time, considering that both the third optical path and the second optical path are focused and imaged for the calibration Mark, in the preferred embodiment, after the two visual components are set, the reflector of the third optical path and the reflector of the second optical path (i.e., the second reflector 5052) are preferably arranged at intervals in the X-axis direction, so that the calibration Mark on the calibration plate 2 and the corresponding detection optical paths in the two visual components can be focused and imaged in sequence through displacement in the X-axis direction.

[0081] Through the above-mentioned arrangement of the bonding component 1, the calibration plate 2, the two displacement mechanisms and the two visual components, the bonding head 101 can complete the two focusing imaging of the calibration mark and the focusing imaging of the first detection mark and the second detection mark after completing the material collection of the chip to be bonded 7. By obtaining the relative coordinate value between the two detection marks and the calibration mark, the relative coordinate value between the two detection marks can be converted, and then the compensation position coordinate ( x , y ,θ). After that, the chip to be mounted 7 and the target chip 8 can be adjusted to a completely aligned position by controlling the plane adjustment module 102, and finally the alignment bonding between the two chips is completed.

[0082] As another aspect of the present invention, based on the aforementioned wafer bonding device, a wafer bonding method is further proposed, which is implemented by using the wafer bonding device and includes the following steps: (1) Driven by the first displacement mechanism 3, the bonding assembly 1 is driven to the material removal station and the material removal of the chip to be bonded 7 is completed; (2) Control the first displacement mechanism 3 to work and drive the bonding head 101 to the second visual component 6. At this time, the two detection light paths on the second visual component 6 are focused and imaged at the calibration mark (corresponding to the third light path) and the first detection mark (corresponding to the fourth light path), respectively, to obtain the coordinate information of the first detection mark relative to the calibration mark; (3) Control the first visual component 5 and the target chip 8 to align the first optical path of the first visual component 5 with the second detection mark on the target chip 8 to obtain the coordinate information of the second detection mark; Obviously, it can be understood that at this time, the bonding head 101 is far away from the field of view of the first visual component 5, and the second optical path is located on the side of the first optical path away from the bonding head 101. There is no obstruction in the direction of the optical path. However, there is no content at the focus point of the second optical path. Therefore, at this time, the second optical path is not imaged in the camera module. Figure 5 as shown in .

[0083] (4) Keeping the relative position between the first visual component 5 and the carrier 10 unchanged, the plane adjustment module 102 is controlled to work, driving the bonding head 101 to move horizontally until the second optical path is focused and imaged at the calibration mark, obtaining the coordinate information of the calibration mark at this time, and obtaining the coordinate information of the second detection mark relative to the calibration mark based on this; It is not difficult to find that when the calibration Mark is focused and imaged in the camera module of the first visual component 5, the first optical path is blocked by the bonding head 101 and cannot be imaged. Figure 6 At this time, the actual position coordinates of the calibration Mark can be determined in combination with the displacement of the plane adjustment module 102 .

[0084] (5) The relative position coordinates between the first detection mark and the second detection mark are obtained based on the coordinate information of the first detection mark relative to the calibration mark and the coordinate information of the second detection mark relative to the calibration mark, and the compensation position coordinates of the chip to be mounted 7 that needs to be displaced when the two chips are aligned are obtained based on this ( x , y , θ); (6) The plane adjustment module 102 is controlled to work according to the compensation position coordinates to accurately align the chip to be attached 7 with the target chip 8; thereafter, the second displacement mechanism 4 is controlled to work, and the bonding head 101 drives the chip to be attached 7 to be pressed down and completes the bonding with the target chip 8.

[0085] The process in (1) to (6) is repeated to complete the bonding process between the plurality of chips to be bonded 7 and the corresponding target chips 8.

[0086] The wafer bonding equipment based on dual-focus imaging in the present invention has a compact structure and is easy to use. It can realize the imaging of the detection Marks on the two chips and the calibration Marks on the calibration plate based on the dual-focus imaging principle, accurately obtain the relative position coordinates between the two detection Marks on the two chips, and thereby obtain the compensation position coordinates required for the alignment between the two chips, thereby ensuring the alignment accuracy of the chip to be bonded and the target chip before bonding, improving the quality of chip bonding processing, and reducing the defective rate of chip processing, and has good practical value and economic benefits.

[0087] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wafer bonding device based on dual-focus imaging, characterized in that: include: A carrier platform, used for carrying the target chip; A bonding assembly, the bonding assembly comprising a bonding head and a plane adjustment module; The bonding head is used for picking up the chip to be bonded and pressing down for bonding. It is connected to the plane adjustment module, and the plane adjustment module can perform XYθ adjustment within the plane; A first displacement mechanism and a second displacement mechanism are assembled and connected to each other; the first displacement mechanism is a horizontal displacement mechanism, used to drive the second displacement mechanism to perform horizontal displacement in a first direction; the bonding assembly is connected to the second displacement mechanism, so that the bonding head can be driven by the second displacement mechanism to perform lifting and lowering displacement in a second direction to approach or move away from the bearing platform; A calibration plate, which is arranged on one side of the bonding head along the first direction, is made of a transparent material, and has a calibration mark on its top surface or bottom surface; A first visual component, wherein the light outlet of the first visual component is used to simultaneously output a first optical path and a second optical path that are parallel to each other, the focusing optical paths of the two optical paths are equal, and a first optical path difference is formed in the first visual component; the first optical path difference is equal to the spacing between a second detection Mark and a calibration Mark on the target chip in the exit directions of the two optical paths, and the optical path of the first optical path in the visual component is smaller than the optical path of the second optical path in the visual component; the first optical path can be focused and imaged when irradiated on the second detection Mark, and the second optical path can be focused and imaged when irradiated on the calibration Mark; A second visual component, wherein the light outlet of the second visual component is used to simultaneously output a third optical path and a fourth optical path which are parallel to each other and have equal focusing optical paths; wherein the optical path of the third optical path in the visual component is smaller than the optical path of the fourth optical path in the visual component, and the second optical path difference between the two optical paths in the visual component is equal to the spacing between the first detection mark and the calibration mark of the chip to be attached on the bonding head in the emission directions of the two optical paths, so that when the bonding component is aligned with the second visual component, the third optical path can focus on the calibration mark and the fourth optical path can focus on the first detection mark at the same time; The second visual component is used to obtain the relative position coordinates of the first detection Mark and the calibration Mark, and the second visual component is used to obtain the relative position coordinates of the second detection Mark and the calibration Mark, and the relative position coordinates between the two detection Marks are converted; according to the relative position coordinates, the plane adjustment module is controlled to adjust the position of the chip to be mounted, so as to achieve accurate alignment of the two chips before bonding.

2. The wafer bonding device based on dual-focus imaging according to claim 1, characterized in that: The material taking position of the chip to be mounted, the carrying platform, and the second visual component are arranged at intervals in the first direction, and the second visual component is arranged between the material taking position and the carrying platform.

3. The wafer bonding equipment based on dual-focus imaging according to claim 1, characterized in that: At least one visual component includes a camera module and a reflector assembly; The camera module is used to output a pair of parallel detection lights and form two optical paths with equal focusing optical paths. The reflector group is arranged corresponding to the light outlet of the visual component, and includes a first reflector and a second reflector arranged side by side in the spacing direction of the two optical paths; and the first reflector protrudes more than the second reflector in the direction of the two optical paths, and the protruding distance of the first reflector is equal to the optical path difference between the two optical paths in the visual component.

4. The wafer bonding equipment based on dual-focus imaging according to claim 3, characterized in that: The camera module is directly arranged on one side of the reflector group, and the camera module directly directs the two parallel light paths generated to the reflector group; or At least one reversing mirror is arranged between the camera module and the reflector group for controlling the reversing of two parallel light paths.

5. The wafer bonding equipment based on dual-focus imaging according to claim 3, characterized in that: The optical path directions of the two detection lights emitted by the camera module are parallel to the optical path directions emitted from the light outlet of the visual component, and a first reversing mirror and a second reversing mirror are arranged between the camera module and the reflector group; The first deflection mirror is arranged corresponding to the camera module, and is used to deflect the detection light transmitted along the second direction to be transmitted horizontally; the second deflection mirror is arranged between the reflector group and the first deflection mirror, and is used to deflect the two detection lights to a horizontal direction perpendicular to the first direction.

6. The wafer bonding equipment based on dual-focus imaging according to any one of claims 1 to 5, characterized in that: The first displacement mechanism comprises a translation guide rail extending along a first direction and a translation motor mounted on the translation guide rail, wherein the translation motor can reciprocate along the first direction on the translation guide rail; The second displacement mechanism includes a lifting guide rail extending along the second direction and a lifting motor mounted on the lifting guide rail; the lifting guide rail is connected to the translation motor and can follow the translation motor to perform reciprocating translation in the first direction; the lifting motor is mounted on the lifting guide rail and can move back and forth along the second direction on the lifting guide rail; and the plane adjustment module is connected to the lifting motor and can follow the lifting motor to move back and forth in the second direction.

7. The wafer bonding equipment based on dual-focus imaging according to claim 6, characterized in that: The first displacement mechanism also includes a fixed plate fixedly connected to the translation motor; and the lifting guide rail and the first visual component are fixedly mounted on the fixed plate at the same time, and can follow the fixed plate to perform reciprocating translation.

8. The wafer bonding equipment based on dual-focus imaging according to claim 7, characterized in that: A translation component is provided on the fixed plate corresponding to the first visual component or the lifting guide rail; The first visual component or the lifting guide rail is mounted on the fixed plate via a translation component, and the relative position of the first visual component and the lifting guide rail in a first direction can be adjusted by control of the translation component.

9. The wafer bonding equipment based on dual-focus imaging according to any one of claims 1 to 5, 7 and 8, characterized in that: The internal components of the two visual components are the same; the light paths emitted from the light outlets of the two visual components are parallel and in opposite directions.

10. A wafer bonding method based on dual-focus imaging, using the wafer bonding device based on dual-focus imaging according to any one of claims 1 to 9, characterized in that: The process includes the following: (1) The bonding head completes the material collection of the chip to be bonded; (2) Controlling the movement of the first displacement mechanism to drive the bonding head to the second visual component, so that the third optical path and the fourth optical path are focused and imaged at the calibration mark and the first detection mark respectively, and obtaining the coordinate information of the first detection mark relative to the calibration mark; (3) Controlling the first visual component to align with the second detection Mark, completing the focus imaging of the second detection Mark through the first optical path, and obtaining the coordinate information of the second detection Mark; (4) Control the bonding head to translate, align the calibration plate with the first visual component, complete the focus imaging of the calibration mark through the second optical path, obtain another coordinate information of the calibration mark, and obtain the coordinate information of the second detection mark relative to the calibration mark based on this; (5) Obtain the relative position coordinates between the two detection marks based on the coordinate information of the first detection mark relative to the calibration mark and the coordinate information of the second detection mark relative to the calibration mark, and thereby obtain the compensation position coordinates of the chip to be mounted that needs to be displaced when the two chips are aligned; (6) Controlling the plane adjustment module to work according to the compensation position coordinates to accurately align the chip to be bonded with the target chip; thereafter, controlling the second displacement mechanism to work, and driving the bonding head to press the chip to be bonded downward to complete bonding with the target chip.

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