Wafer bonding apparatus and wafer bonding method based on bifocal imaging

Abstract

The application discloses a kind of based on bifocal imaging wafer bonding equipment and wafer bonding method, belong to bonding processing equipment field, it includes bearing platform, bonding assembly and the first displacement mechanism and the second displacement mechanism being set to corresponding bonding assembly, through the alignment of corresponding chip to be pasted, target chip setting calibration plate, first vision assembly and second vision assembly, using the setting of the pair of detection light of equal focusing optical path in vision assembly, and the setting of the optical path difference of two light paths in vision assembly, so that two vision assemblies can realize the focusing imaging of calibration Mark and the detection Mark on two chips respectively, to obtain the relative position of two detection Marks, obtain the position compensation information required when two chips are accurately aligned, finally realize the accurate alignment before two chip bonding.The wafer bonding equipment in the application has compact structure, is convenient to use, can ensure the alignment accuracy of chip to be pasted and target chip before bonding, improve the quality of chip bonding processing, reduce the defective rate of chip processing.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bonding processing equipment, and particularly relates to a wafer bonding device based on double-focus imaging and a wafer bonding method. BACKGROUND

[0002] Hybrid bonding technology is a new type of semiconductor packaging technology, which realizes high-strength and high-reliability interlayer bonding through mechanisms such as intermolecular force, metal diffusion, and eutectic welding, can integrate homogeneous or heterogeneous materials, realizes vertical stacking, and provides convenience for the development of three-dimensional integrated circuits (3D-IC).

[0003] Compared with traditional packaging technology, hybrid bonding has no bump, can realize higher density integration, and greatly reduces chip power consumption, and has extremely promising application prospects in many fields.

[0004] Generally, the hybrid bonding process can be divided into three process stages of surface treatment, alignment bonding, and post-treatment. Among them, the surface treatment process is to clean and activate the chip and wafer surfaces by using plasma or acid-base to enhance adhesion. The alignment bonding is to complete the high-precision alignment of the chip and the wafer, ensure that the pads are one-to-one corresponding, and then directly bond through van der Waals force, intermolecular and interatomic force under the action of a certain pressure. The post-treatment process is to strengthen the bonding by annealing, and the annealing temperature is usually 200-300℃. In the whole process, the alignment accuracy is the key indicator affecting the electrical connection and reliability of the chip, and once the alignment accuracy is problematic, 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 the first problem to be solved when trying to improve the efficiency and yield of hybrid bonding processing. SUMMARY

[0005] In view of one or more of the above defects or improvement needs of the prior art, the present application provides a wafer bonding device based on double-focus imaging and a wafer bonding method, which can accurately realize the accurate alignment of the chip to be pasted 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-mentioned purpose, in one aspect of the present application, a wafer bonding device based on double-focus imaging is provided, which comprises:

[0007] A carrying table for carrying a target chip;

[0008] A 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 pasted, and is connected to the plane adjustment module and can be adjusted in the XYθ plane by the plane adjustment module;

[0009] The first displacement mechanism and the second displacement mechanism are assembled to each other; the first displacement mechanism is a horizontal displacement mechanism, which drives the second displacement mechanism to horizontally displace 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 vertically displace in a second direction to approach or move away from the supporting table;

[0010] A calibration plate is arranged on one side of the bonding head along the first direction, which is made of transparent material and provided with calibration marks on the top surface or the bottom surface;

[0011] The first visual assembly is used to simultaneously output the first light path and the second light path which are parallel to each other, the focusing optical path of the two light paths is equal, and the first optical path difference is formed in the first visual assembly; the first optical path difference is equal to the interval of the second detection mark and the calibration mark on the target chip in the direction of the two light paths, and the optical path of the first light path in the visual assembly is less than the optical path of the second light path in the visual assembly; the first light path can be focused and imaged when irradiating the second detection mark, and the second light path can be focused and imaged when irradiating the calibration mark;

[0012] The second visual assembly is used to simultaneously output the third light path and the fourth light path which are parallel to each other and have equal focusing optical paths; wherein the optical path of the third light path in the visual assembly is less than the optical path of the fourth light path in the visual assembly, and the second optical path difference of the two light paths in the visual assembly is equal to the interval of the first detection mark and the calibration mark on the bonding head in the direction of the two light paths, so that when the bonding assembly and the second visual assembly are aligned, the third light path can be focused and imaged on the calibration mark, and the fourth light path can be focused and imaged on the first detection mark at the same time;

[0013] The relative position coordinates of the first detection mark and the calibration mark are obtained by using the second visual assembly, the relative position coordinates of the second detection mark and the calibration mark are obtained by using the second visual assembly, and the relative position coordinates between the two detection marks are obtained by conversion; according to the relative position coordinates, the position of the chip to be bonded is adjusted by the plane adjustment module, so as to realize accurate alignment before bonding of the two chips.

[0014] As a further improvement of the present application, the material taking position of the chip to be bonded, the supporting table and the second visual assembly are arranged in the first direction, and the second visual assembly is arranged between the material taking position and the supporting table.

[0015] As a further improvement of the present application, at least one visual assembly comprises a camera module and a mirror group;

[0016] The camera module is used to output a pair of parallel detection lights and form two pairs of light paths with equal focal lengths, the mirror group is arranged corresponding to the light outlet of the vision assembly, which comprises a first mirror and a second mirror arranged side by side in the interval direction of the two light paths; and the first mirror protrudes in the direction of the two light paths from the second mirror, and the protruding distance of the first mirror is equal to the optical path difference of the two light paths in the vision assembly.

[0017] As a further improvement of the application, the camera module is directly arranged on one side of the mirror group, and the two parallel light paths generated by the camera module are directly emitted to the mirror group;

[0018] Or

[0019] At least one reversing mirror is arranged between the camera module and the mirror group for reversing control of the two parallel light paths.

[0020] As a further improvement of the application, the light path direction of the two detection lights emitted by the camera module is parallel to the light path direction emitted from the light outlet of the vision assembly, and a first reversing mirror and a second reversing mirror are arranged between the camera module and the mirror group;

[0021] The first reversing mirror is arranged corresponding to the camera module for reversing the detection light transmitted along the second direction into horizontal transmission; the second reversing mirror is arranged between the mirror group and the first reversing mirror for reversing the two detection lights into the horizontal direction perpendicular to the first direction.

[0022] As a further improvement of the application, the first displacement mechanism comprises a translation guide rail arranged in the first direction and a translation motor assembled on the translation guide rail, and the translation motor can reciprocate along the first direction on the translation guide rail;

[0023] The second displacement mechanism comprises a lifting guide rail extending in the second direction and a lifting motor assembled on the lifting guide rail; the lifting guide rail is connected with the translation motor and can reciprocate in the first direction following the translation motor; the lifting motor is assembled on the lifting guide rail and can reciprocate in the second direction on the lifting guide rail; and the plane adjustment module is connected on the lifting motor and can reciprocate in the second direction following the lifting motor.

[0024] As a further improvement of the application, the first displacement mechanism further comprises a fixed plate fixedly connected with the translation motor; and the lifting guide rail and the first vision assembly are fixedly installed on the fixed plate and can reciprocate following the fixed plate.

[0025] As a further improvement of the application, a translation assembly is arranged on the fixed plate corresponding to the first vision assembly or the lifting guide rail.

[0026] The first visual assembly or the lifting guide rail is installed on the fixed plate through a translation assembly, and the relative position adjustment of the first visual assembly and the lifting guide rail in a first direction can be realized by controlling the translation assembly.

[0027] As a further improvement of the present application, the internal components of the two visual assemblies are the same, and the light path directions of the light emitted from the light outlets of the two visual assemblies are parallel and opposite.

[0028] Another aspect of the present application also provides a wafer bonding method based on double-focus imaging, which utilizes the wafer bonding device based on double-focus imaging, and includes the following processes:

[0029] (1) The bonding head completes the picking of the chip to be pasted;

[0030] (2) The first displacement mechanism is controlled to move, and the bonding head is driven to the second visual assembly, so that the third light path and the fourth light path are respectively focused and imaged at the calibration Mark and the first detection Mark, and the coordinate information of the first detection Mark relative to the calibration Mark is obtained;

[0031] (3) The first visual assembly is controlled to align with the second detection Mark, and the focusing imaging of the second detection Mark is completed by the first light path, and the coordinate information of the second detection Mark is obtained;

[0032] (4) The bonding head is controlled to translate, and the calibration plate is aligned with the first visual assembly, and the focusing imaging of the calibration Mark is completed by the second light path, and another coordinate information of the calibration Mark is obtained, and the coordinate information of the second detection Mark relative to the calibration Mark is obtained accordingly;

[0033] (5) The relative position coordinates between the two detection Marks are obtained according to 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 pasted when the two chips are aligned are obtained;

[0034] (6) The plane adjustment module is controlled to work according to the compensation position coordinates, and the chip to be pasted is accurately aligned with the target chip; thereafter, the second displacement mechanism is controlled to work, and the chip to be pasted is driven down by the bonding head and the wafer bonding is completed.

[0035] The above improved technical features can be combined with each other as long as they do not conflict with each other.

[0036] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects:

[0037] (1) The wafer bonding device based on bifocal imaging of the application comprises a bearing table, a bonding assembly, and a first displacement mechanism and a second displacement mechanism arranged corresponding to the bonding assembly, a calibration plate, a first visual assembly and a second visual assembly are arranged corresponding to the alignment of the chip to be pasted and the target chip, the detection light of the pair of equal focal length in the visual assembly is arranged, and the optical path difference of the two light paths in the visual assembly is arranged, so that the two visual assemblies can realize the focusing imaging of the calibration Mark and the detection Mark on the two chips respectively, thereby realizing the acquisition of the relative position of the two detection Marks, and further obtaining the position compensation information required when the two chips are accurately aligned, finally realizing the accurate alignment before the bonding of the two chips, improving the efficiency and precision of the alignment and bonding of the chip to be pasted and the target chip, and reducing the failure rate of the chip bonding process.

[0038] (2) The wafer bonding method based on bifocal imaging of the application is realized by using the wafer bonding device designed preferably, the steps are simple, the control is convenient, the mechanism of bifocal imaging can be used to accurately realize the alignment process before the bonding of the chip to be pasted and the target chip, improve the efficiency of chip alignment and wafer bonding, and reduce the cost of chip bonding processing.

[0039] (3) The wafer bonding device based on bifocal imaging of the application has compact structure and convenient use, can realize the imaging of the detection Mark on the two chips and the calibration Mark on the calibration plate based on the bifocal imaging principle respectively, accurately acquire the relative position coordinates of the two detection Marks on the two chips, and acquire the compensation position coordinates required when the two chips are aligned, ensure the alignment accuracy of the chip to be pasted and the target chip before bonding, improve the quality of chip bonding processing, reduce the failure rate of chip processing, have good practical value and economic benefit. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0041] Figure 1 is the overall structure schematic diagram of the wafer bonding device based on bifocal imaging in the embodiments of the application;

[0042] Figure 2 is the internal component arrangement side view of the first visual assembly in the embodiments of the application;

[0043] Figure 3 is the internal component arrangement top view of the first visual assembly in the embodiments of the application;

[0044] Figure 4is a schematic view of the first visual assembly focusing on the target chip in the embodiment of the present application;

[0045] Figure 5 is a schematic view of the first visual assembly focusing on the calibration plate in the embodiment of the present application;

[0046] Figure 6 is a schematic view of the second visual assembly focusing on the double focusing operation in the embodiment of the present application;

[0047] In all the drawings, the same reference signs refer to the same technical features, specifically:

[0048] 1, bonding assembly; 2, calibration plate; 3, first displacement mechanism; 4, second displacement mechanism; 5, first visual assembly; 6, second visual assembly; 7, to-be-pasted chip; 8, target chip; 9, wafer; 10, bearing table;

[0049] 101, bonding head; 102, plane adjustment module;

[0050] 301, translation guide rail; 302, translation motor;

[0051] 401, lifting guide rail; 402, lifting motor;

[0052] 501, camera; 502, lens; 503, first turning mirror; 504, second turning mirror; 505, mirror group; 5051, first mirror; 5052, second mirror. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the present application clearer and more comprehensible, the present application is further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0054] In the description of the present application, it should be understood that, unless otherwise explicitly specified and limited, the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0055] In addition, the terms "first", "second", etc. are used only for descriptive purposes and are not to be construed as indicating or implying relative importance or an ordered ranking of the indicated technical features. Thus, features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited.

[0056] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0057] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0058] Embodiment:

[0059] For the wafer bonding device based on bifocal imaging of the present application, it aims to realize accurate alignment of the chip to be pasted 7 and the target chip 8 before chip bonding, and ensure the accuracy and reliability of chip bonding.

[0060] It should be noted that when the bonding device performs bonding operation, the bonding assembly 1 needs to at least go through two processes of taking (taking the chip to be pasted 7) and displacement (moving the chip to be pasted 7 from the taking position to above the target chip 8), and both processes are completed under precise control.

[0061] That is to say, when the bonding head 101 takes the chip to be pasted 7, the chip to be pasted 7 has a relatively accurate alignment relationship with the bonding head 101 in the bonding assembly 1, and the deviation between the two will not be too large. At the same time, after moving to above the target chip 8, there will be no obvious misalignment between the two chips.

[0062] Briefly, the wafer bonding device in the preferred embodiment is intended to achieve accurate alignment of two chips to be bonded under a certain alignment accuracy, and through the setting of corresponding components, the small errors introduced by the mechanical movement of the device are compensated, so as to ensure sufficient alignment of the two chips before bonding and improve the quality of chip bonding.

[0063] Specifically, the wafer bonding device in the preferred embodiment, as shown in Figures 1-6 , includes a bonding component 1, a first visual component 5, a second visual component 6, and a carrying table 10, and is provided with a first displacement mechanism 3 and a second displacement mechanism 4 corresponding to the movement control of the bonding component 1.

[0064] For 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 move horizontally in the first direction (i.e. the X-axis direction in the figure), and through the control of the first displacement mechanism 3, the processes of taking the chip 7 to be bonded, aligning with the second visual component 6, and aligning with the target chip 8 are completed.

[0065] Meanwhile, the second displacement mechanism 4 in the preferred embodiment is a Z-axis displacement mechanism in the figure, which is used to drive the bonding component 1 to move reciprocally in the second direction (i.e. the Z-axis direction in the figure), and through the control of the second displacement mechanism 4, the process of step bonding of the chip 7 to be bonded is completed.

[0066] It should be noted that, regarding the three coordinate systems in Figures 1-6 , the "O" in the coordinate system legend represents that the corresponding coordinate direction is perpendicular to the paper surface inward, for example Figure 1 the Y-axis in Figure 2 , the X-axis in Figure 3 ; and the " " in the legend represents that the corresponding coordinate direction is perpendicular to the paper surface outward, for example the Z-axis in

[0067] .

[0068] More specifically, the bonding component 1 in the preferred embodiment includes a bonding head 101 connected to a plane adjustment module 102, so that the bonding head 101 can be adjusted in the XYθ plane under the driving of the plane adjustment module 102.

[0069] With the setting of the plane adjustment module 102, the adjustment of the plane position of the bonding head 101 after visual detection can be completed, and accurate alignment of the chip 7 to be bonded and the target chip 8 before bonding can be achieved.

[0070] Meanwhile, the displacement control of the corresponding bonding assembly 1 is also combined with the first displacement mechanism 3 and the second displacement mechanism 4. The planar adjustment module 102 of the bonding assembly 1 is connected to the second displacement mechanism 4 and can be reciprocally displaced under the driving of the second displacement mechanism 4 to approach or move away from the carrier table 10.

[0071] In Figure 1 In the preferred embodiment shown, the second displacement mechanism 4 is a lifting displacement mechanism, i.e., a Z-axis displacement mechanism, which can drive the bonding assembly 1 to reciprocally move up and down to approach or move away from the carrier table 10 in the Z-axis direction (vertical direction) and finally complete the pressing bonding process after the alignment of the chip to be bonded 7 and the target chip 8.

[0072] Meanwhile, 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 assembly 1 connected to the second displacement mechanism 4 in the horizontal direction can be realized.

[0073] In Figure 1 In the preferred embodiment shown, the first displacement mechanism 3 is an X-axis displacement mechanism, which can reciprocally displace in the X-axis direction. Meanwhile, the picking station of the chip to be bonded 7 and the carrier table 10 are spaced apart in the X-axis direction in the preferred embodiment, so that the bonding assembly 1 can switch between the picking station and the bonding station through horizontal displacement.

[0074] Exemplarily, both displacement mechanisms in the preferred embodiment preferably include a guide rail and a motor assembled on the respective guide rail, and the reciprocating displacement in the corresponding direction is realized by the control of the motor and the guidance of the guide rail.

[0075] For example, the first displacement mechanism 3 includes a translation guide rail 301 and a translation motor 302, and 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 reciprocally displace horizontally following the translation motor 302. Correspondingly, the planar adjustment module 102 is connected to the lifting motor 402 and can reciprocally displace vertically following the lifting motor 402.

[0076] Further, the alignment of the chip to be bonded 7 and the target chip 8 before bonding on the corresponding bonding head 101 is also combined with the first vision assembly 5 and the second vision assembly 6, and the position detection of the chip to be bonded 7 and the target chip 8 is accurately realized by the use of the two vision assemblies, and finally the accurate alignment before the bonding of the two chips is completed.

[0077] In actual settings, 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, the detection direction of the first visual component 5 is downward, and is used for position detection of the target chip 8. Correspondingly, the detection direction of the second visual component 6 is upward, and is used for position detection of the chip 7 to be attached.

[0078] In order to ensure that the position detection of the two chips has the same reference and target, a calibration plate 2 is preferably arranged on one side of the bonding head 101, the calibration plate 2 is made of transparent material, and a calibration Mark that can be focused and shot by the two visual components is arranged on the top surface or the bottom surface thereof.

[0079] Exemplarily, the calibration plate 2 in the preferred embodiment is transparent glass or glass with an anti-reflection film plated on the surface.

[0080] In the preferred embodiment, the calibration Mark is arranged on the bottom surface of the calibration plate 2, and subsequent further elaboration is made by taking this as an example. Of course, if the calibration Mark is arranged on the top surface of the calibration plate 2, the setting form of the two visual components can be adjusted correspondingly, which is not described herein.

[0081] Meanwhile, corresponding focus Marks are arranged on the end surfaces of the two chips facing each other, that is, a first detection Mark arranged on the bottom surface of the chip 7 to be attached and a second detection Mark arranged on the top surface of the target chip 8. By acquiring the relative positions of the at least two sets of detection Marks, the relative positions of the two chips can be correspondingly acquired, and accurate position compensation information can be provided for the adjustment action of the plane adjustment module 102, so as to drive the chip 7 to be attached to complete the corresponding position adjustment.

[0082] In combination with the foregoing description, it can be understood that after the material taking and displacement control of the chip 7 to be attached are actually completed, a certain alignment relationship is met between the chip 7 to be attached and the target chip 8, and after the alignment detection of the two chips is completed, only a small-amplitude in-plane XYθ adjustment is needed, and the complete alignment between the two chips can be realized.

[0083] Further, the first visual component 5 of the preferred embodiment is arranged on the side of the bonding assembly 1 where the calibration plate 2 is arranged, the field of view of the light outlet thereof is downward, and a pair of parallel detection light paths (that is, the light path A and the light path B in Figure 2 The focusing optical paths of the two detection light paths are equal.

[0084] Meanwhile, the optical paths of the two detection light paths inside the first visual component 5 have a certain optical path difference, and the two detection light paths are respectively a first light path and a second light path, the optical path of the first light path inside the visual component is smaller than that of the second light path, and the optical path difference of the two light paths is W1.

[0085] In more detail, the optical path difference W1 of the first light path and the second light path is equal to the interval of 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 light path, i.e. the interval of the calibration Mark and the second detection Mark in the Z-axis direction. Figure 1

[0086] In this way, the two detection light paths with the optical path difference in the first visual assembly 5 can be respectively focused and imaged at the calibration Mark and the second detection Mark.

[0087] Obviously, after being emitted from the light outlet of the first visual assembly 5, the optical path of the second light path (the dashed line on the left in Figure 5 ) is shorter than the optical path of the first light path (the dashed line on the right in Figure 5 ), and the optical path difference is just equal to the optical path difference of the second light path in the visual assembly from the first light path, i.e. W1.

[0088] In actual settings, the two detection light paths with the optical path difference are obtained by the two mirrors arranged in a staggered manner in the visual assembly, such as the first mirror 5051 and the second mirror 5052 in Figure 2 . The two mirrors are arranged at the light outlet of the visual assembly, and the reflecting surfaces thereof are arranged at an acute angle with the axis of the light outlet for reflecting and outputting the detection light path from the camera module. At the same time, the two mirrors are arranged side by side in the interval direction of the two detection light paths, i.e. the reflecting parts of the two mirrors 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 mirror 5051 is more forward than the position of the second mirror 5052, so that the first mirror 5051 reflects the first light path earlier than the second mirror 5052, resulting in the optical path difference of the two detection light paths in the visual assembly. In more detail, the interval of the two mirrors in the direction of the detection light path is just W1.

[0089] In this way, the first mirror 5051 will be shorter than the second mirror 5052 in one of the two parallel light paths, i.e. the optical path of the detection light path reflected from the first mirror 5051 in the visual assembly is shorter than the optical path of the detection light path reflected from the second mirror 5052.

[0090] For example, in the preferred embodiment as shown in Figure 2 , Figure 3 , the detection light paths towards the two mirrors extend along the Y-axis, and the first mirror 5051 protrudes the second mirror 5052 in the Y-axis direction by a distance just equal to W1, so that the originally parallel two detection light beams are reflected by the two mirrors in sequence.

[0091] ​Further, the two mirrors are arranged in a staggered manner in the displacement direction of the first displacement mechanism 3, so that the two detection light paths output after being reflected by the two mirrors are arranged in a staggered manner in the displacement direction of the first displacement mechanism 3.

[0092] It can be understood that the two detection light paths output after being reflected by the two mirrors are spaced apart in the Y-axis direction and the X-axis direction.

[0093] More preferably, in actual arrangement, the two detection light paths of the camera mirror can directly come from the camera module, or come from a synchronous mirror group arranged corresponding to the camera module.

[0094] For example, in the preferred embodiment shown in FIGS. 5A and 5B, the camera module and the mirror 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 mirror is arranged corresponding to the two detection light paths emitted from the lens 502, for example, a first mirror 503 and a second mirror 504 in FIG. 5B, the former is used to convert the vertical light path emitted by the camera module into a horizontal light path, and the latter is used to realize the angle conversion of the horizontal light path in the plane. Figure 2 Figure 3 Figure 3

[0095] It can be understood that in the above embodiment, the camera module can also be arranged corresponding to the position of the first mirror 503, and emit two synchronous detection light paths to the second mirror 504, at this time, the number of mirrors arranged is one.

[0096] In addition, in the above embodiment, if the camera module is arranged at the position of the second mirror 504, at this time, no mirror is arranged, and the two parallel detection light paths emitted synchronously are directly reflected by the mirror group 505.

[0097] More specifically, the second mirror 5052 in the preferred embodiment is arranged on the side of the first mirror 5051 away from the bonding assembly 1, and when the two chips are aligned with each other, the axis of the first light path of the first mirror 5051 passes through the second detection Mark on the target chip 8, and the axis of the second light path of the second mirror 5052 passes through the calibration Mark on the calibration plate 2.

[0098] In a preferred embodiment, the setting position of the first visual assembly 5 can be relatively fixed, and the alignment of different target chips 8 on the wafer 9 with the first visual assembly 5 is realized by controlling the displacement of the wafer 9 on the carrying table 10, so as to ensure that the axis of the first light path always passes through the second detection Mark. At this time, the bonding assembly 1 is driven by the two displacement mechanisms to realize the displacement movement relative to the first visual assembly 5.

[0099] ​​​In another preferred embodiment, the first visual assembly 5 is preferably arranged on the displacement mechanism and can be displaced relative to the carrier table 10.

[0100] More preferably, the first visual assembly 5 is preferably arranged on the first displacement mechanism 3, for example, fixedly connected with the translation motor 302, and in this case, the first visual assembly 5 can be synchronously horizontally displaced with the second displacement mechanism 4 and the bonding assembly 1 connected to the second displacement mechanism 4. Correspondingly, the relative displacement between the bonding assembly 1 and the first visual assembly 5 can be realized by the planar adjustment module 102 or a displacement mechanism additionally arranged on the bonding assembly 1.

[0101] Illustratively, in a specific preferred embodiment, the first displacement mechanism 3 includes a fixed plate fixedly connected with the translation motor 302 and can follow the translation motor 302 to reciprocally translate. Correspondingly, the second displacement mechanism 4 and the first visual assembly 5 are preferably arranged on the fixed plate, and the displacement of the fixed plate drives the first visual assembly 5 and the bonding assembly 1 to synchronously displace relative to the carrier table 10. In this case, the relative displacement between the first visual assembly 5 and the bonding head 101 can be realized according to the control of the planar adjustment module 102.

[0102] More specifically, in another specific preferred embodiment, the function of the planar adjustment module 102 is focused on adjusting the compensation position information and not performing large-scale translation adjustment. In this case, the first visual assembly 5 or the lifting guide rail 401 is preferably arranged on the fixed plate through a translation assembly, and the relative position adjustment between the first visual assembly 5 and the second displacement mechanism 4 in the first direction can be realized through the control of the translation assembly. In this way, the control process of the bonding head 101 moving away from or shielding the first light path can be more conveniently realized, for example, the switching process of the state shown in Figure 5 、 Figure 6 .

[0103] Further, the setting mechanism of the second visual assembly 6 in the preferred embodiment is similar to that of the first visual assembly 5, and the second visual assembly 6 can also generate two parallel detection light paths, and the directions of the two detection light paths emitted by the second visual assembly 6 are opposite to those of the two detection light paths emitted by the first visual assembly 5.

[0104] For example, in the preferred embodiment shown in Figure 1 , the detection light path emitted by the first visual assembly 5 is along the negative direction of the Z axis, and the detection light path emitted by the second visual assembly 6 is along the positive direction of the Z axis.

[0105] In more detail, the structural composition of the second vision assembly 6 is preferably identical to that of the first vision assembly 5, and the two detection light paths outputted from the light outlet of the second vision assembly 6 are respectively a third light path and a 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 vision assembly is smaller than that of the fourth light path in the vision assembly, i.e. the distance between the focusing point of the third light path and the light outlet of the vision assembly is greater than that between the focusing point of the fourth light path and the light outlet of the vision assembly, as shown in Figure 4 the left dashed line in the figure is the third light path, and the right dashed line is the fourth light path.

[0106] More specifically, in the second vision assembly 6, the optical path difference W2 between the third light path and the fourth light path is equal to the distance between the calibration Mark and the first detection Mark in the axial direction of the light path, i.e. the distance between the two Marks in the Z-axis direction. Figure 1

[0107] 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 arranged on the bottom surface of the calibration plate 2, at this time, the distance between the calibration Mark and the first detection Mark in the optical axis is just equal to the thickness of the chip 7 to be bonded.

[0108] In actual arrangement, the bottom surface of the calibration plate 2 does not protrude from the bottom surface of the chip 7 after being taken out by the bonding head 101, and it is further preferred that the bottom surface of the calibration plate 2 does not protrude from the bottom surface of the bonding head 101, so as to reduce the impact of the calibration plate 2 on the bonding of the chip 7 to be bonded.

[0109] By using the arrangement of the two detection light paths in the second vision assembly 6, after the light outlet of the second vision assembly 6 is vertically aligned with the bonding assembly 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 7 to be bonded.

[0110] Preferably, in actual arrangement, the second vision assembly 6 is arranged between the taking-out position of the chip 7 to be bonded and the support table 10, and the line connecting the three is preferably parallel to the displacement direction of the first displacement mechanism 3, so that the bonding assembly 1 can be switched between the taking-out position of the chip 7 to be bonded, the second vision assembly 6 and the support table 10 under the driving of the first displacement mechanism 3.

[0111] In more detail, considering that the arrangement form of the second vision assembly 6 can be the same as that of the first vision assembly 5, in the second vision assembly 6, a pair of reflecting mirror groups can also be arranged to control the optical path difference of the two detection light paths.

[0112] For example, Figure 1 ​The preferred embodiment shown in the figure is taken as an example, at this time, the mirror corresponding to the third light path protrudes the mirror of the fourth light path in the Y axis direction, and the protruding distance is just equal to W2. Meanwhile, considering that the third light path and the second light path are both focused on the imaging of the calibration Mark, in the preferred embodiment, after the setting of the two visual components is completed, the mirror of the third light path and the mirror of the second light path (i.e. the second mirror 5052) are preferably spaced apart in the X axis direction, so that through the displacement in the X axis direction, the calibration Mark on the calibration board 2 and the corresponding detection light path in the two visual components can be sequentially focused and imaged.

[0113] Through the above setting of the bonding assembly 1, the calibration board 2, the two displacement mechanisms and the two visual components, the bonding head 101 can sequentially complete the two times of focused imaging of the calibration Mark and the focused imaging of the first detection Mark and the second detection Mark after the material taking of the chip 7 to be bonded is completed. Through the acquisition of the relative coordinate values between the two detection Marks and the calibration Mark, the relative coordinate values between the two detection Marks can be calculated, and then the compensation position coordinates (X, Y, θ) of the chip 7 to be bonded which need to be displaced are obtained. x y ,θ). Thereafter, by using the control of the planar adjustment module 102, the chip 7 to be bonded and the target chip 8 can be adjusted to the completely aligned position, and finally the alignment bonding between the two chips is completed.

[0114] As another aspect of the present application, on the basis of the foregoing wafer bonding device, a wafer bonding method is further proposed, which is realized by using the wafer bonding device, and includes the following steps:

[0115] (1) The bonding assembly 1 is driven to the material taking station by the first displacement mechanism 3, and the material taking of the chip 7 to be bonded is completed;

[0116] (2) The first displacement mechanism 3 is controlled to work, and the bonding head 101 is driven to the second visual component 6, at this time, the two detection light paths on the second visual component 6 are respectively focused and imaged at the calibration Mark (corresponding to the third light path) and the first detection Mark (corresponding to the fourth light path), and the coordinate information of the first detection Mark relative to the calibration Mark is obtained;

[0117] (3) The first visual component 5 is controlled to align with the target chip 8, so that the first light path of the first visual component 5 is focused and imaged with the second detection Mark on the target chip 8, and the coordinate information of the second detection Mark is obtained;

[0118] ​Obviously, it can be understood that the bonding head 101 is away from the field of view range of the first visual assembly 5 at this time, the second light path is located on the side of the first light path away from the bonding head 101, and there is no obstruction in the light path direction of the second light path, but there is no content at the focus point of the second light path, so the second light path is not imaged by the camera module at this time, as shown in Figure 5 .

[0119] (4) The relative position between the first visual assembly 5 and the support table 10 is kept unchanged, the planar adjustment module 102 is controlled to work, and the bonding head 101 is driven to horizontally displace until the second light path is focused and imaged at the calibration Mark, the coordinate information of the calibration Mark at this time is obtained, and the coordinate information of the second detection Mark relative to the calibration Mark is obtained accordingly;

[0120] It can be found that when the calibration Mark is focused and imaged in the camera module of the first visual assembly 5, the first light path is blocked by the bonding head 101 and cannot be imaged, as shown in Figure 6 . At this time, the actual position coordinates of the calibration Mark can be determined in combination with the displacement of the planar adjustment module 102.

[0121] (5) The relative position coordinates between the first detection Mark and the second detection Mark are obtained according to 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 (x, y, θ) of the to-be-pasted chip 7 required when the two chips are aligned are obtained; x , y , θ);

[0122] (6) The planar adjustment module 102 is controlled to work according to the compensation position coordinates, and the to-be-pasted chip 7 and the target chip 8 are accurately aligned; thereafter, the second displacement mechanism 4 is controlled to work, and the to-be-pasted chip 7 is driven to be pressed down by the bonding head 101 and the bonding of the to-be-pasted chip 7 and the target chip 8 is completed.

[0123] The processes in cycles (1) to (6) are repeated to complete the bonding process between the plurality of to-be-pasted chips 7 and the corresponding target chips 8.

[0124] The wafer bonding device based on double-focus imaging in the application has compact structure and is convenient to use, can respectively realize the imaging of the detection Mark on the two chips and the calibration Mark on the calibration plate based on the double-focus imaging principle, accurately obtain the relative position coordinates between the two detection Marks on the two chips, and obtain the compensation position coordinates required when the two chips are aligned, so as to ensure the alignment accuracy of the to-be-pasted chip and the target chip before bonding, improve the quality of chip bonding processing, reduce the defective rate of chip processing, and have good practical value and economic benefits.

[0125] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A wafer bonding device based on dual-focal imaging, characterized in that, include: A support platform, used to support the target chip; A bonding assembly, comprising a bonding head and a planar adjustment module; The bonding head is used for picking up and pressing the chip to be bonded. It is connected to the plane adjustment module and can be adjusted in the plane by the plane adjustment module. 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 perform vertical displacement in a second direction under the drive of the second displacement mechanism, so as to move closer to or away from the support platform; A calibration plate, which is disposed on one side of the bonding head along the first direction, is made of transparent material and has a calibration mark on its top or bottom surface; A first vision component has an output port that simultaneously outputs a first optical path and a second optical path that are parallel to each other. The two optical paths have equal focusing optical path lengths and form a first optical path difference within the first vision component. The first optical path difference is equal to the distance between the second detection mark and the calibration mark on the target chip in the emission directions of the two optical paths, and the optical path length of the first optical path within the vision component is less than the optical path length of the second optical path within the vision component. The first optical path can focus and image when illuminating the second detection mark, and the second optical path can focus and image when illuminating the calibration mark. The second vision component has an output port that simultaneously outputs a third and a fourth optical path that are parallel to each other and have equal focusing optical path lengths. The optical path length of the third optical path within the vision component is shorter than that of the fourth optical path, and the difference in the second optical path length between the two optical paths within the vision component is equal to the distance 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. This ensures that when the bonding component and the second vision component are aligned, the third optical path can focus and image the calibration mark, while the fourth optical path simultaneously focuses and images the first detection mark. At least one vision component includes a camera module and a mirror group; the camera module is used to output a pair of parallel detection lights and form two optical paths with equal focal optical paths; the mirror group is set corresponding to the light outlet of the vision component, and includes a first mirror and a second mirror arranged side by side in the spacing direction of the two optical paths; and the first mirror protrudes beyond the second mirror in the direction of the two optical paths, and the distance by which the first mirror protrudes is equal to the optical path difference between the two optical paths within the vision component; The relative position coordinates of the first detection mark and the calibration mark are obtained using the second vision component. The relative position coordinates of the second detection mark and the calibration mark are then obtained using the second vision component. The relative position coordinates between the two detection marks are calculated. Based on the relative position coordinates, the planar adjustment module is controlled to adjust the position of the chip to be bonded, so as to achieve accurate alignment of the two chips before bonding.

2. The wafer bonding apparatus based on dual-focal imaging according to claim 1, characterized in that, The chip pick-up position, the carrier platform, and the second vision component are spaced apart in a first direction, and the second vision component is disposed between the chip pick-up position and the carrier platform.

3. The wafer bonding apparatus based on dual-focal imaging according to claim 1, characterized in that, The camera module is directly mounted on one side of the reflector group, and the camera module directly directs the two parallel light paths generated towards the reflector group. or At least one commutator is provided between the camera module and the reflector group for commutation control of the two parallel optical paths.

4. The wafer bonding apparatus based on dual-focal imaging according to claim 1, characterized in that, The optical path direction of the two detection lights emitted by the camera module is parallel to the optical path direction emitted from the light outlet of the vision component, and a first reversing mirror and a second reversing mirror are provided between the camera module and the reflector group. The first commutator is set in the camera module and is used to commutate the detection light transmitted along the second direction to be transmitted horizontally; the second commutator is set between the reflector group and the first commutator and is used to commutate the two detection lights to a horizontal direction perpendicular to the first direction.

5. The wafer bonding apparatus based on dual-focal imaging according to any one of claims 1 to 4, characterized in that, The first displacement mechanism includes 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 a 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 a first direction; the lifting motor is mounted on the lifting guide rail and can move back and forth along the lifting guide rail in a second direction; and the plane adjustment module is connected to the lifting motor and can follow the lifting motor to move back and forth in a second direction.

6. The wafer bonding apparatus based on dual-focal imaging according to claim 5, characterized in that, The first displacement mechanism further includes a fixed plate fixedly connected to the translation motor; and the lifting guide rail and the first vision component are simultaneously fixedly mounted on the fixed plate, and can reciprocate and translate with the fixed plate.

7. The wafer bonding apparatus based on dual-focal imaging according to claim 6, characterized in that, A translation component is provided on the fixed plate corresponding to the first vision component or the lifting guide rail; The first vision component or the lifting guide rail is mounted on the fixed plate via a translation component. By controlling the translation component, the relative position of the first vision component and the lifting guide rail in a first direction can be adjusted.

8. The wafer bonding apparatus based on dual-focal imaging according to any one of claims 1 to 4, 6, and 7, characterized in that, The two vision components have the same internal components; the light emitted from the light outlets of the two vision components are parallel and opposite in direction.

9. A wafer bonding method based on bifocal imaging, comprising using the wafer bonding equipment based on bifocal imaging as described in any one of claims 1 to 8, characterized in that, The process includes the following: (1) The bonding head completes the picking of the chip to be bonded; (2) Control the movement of the first displacement mechanism to drive the bonding head to the second vision component, so that the third optical path and the fourth optical path focus and image at the calibration mark and the first detection mark respectively, and obtain the coordinate information of the first detection mark relative to the calibration mark; (3) Control the first vision component to align with the second detection mark, and complete the focusing and imaging of the second detection mark by the first optical path to obtain the coordinate information of the second detection mark; (4) Control the bonding head to translate and align the calibration plate with the first vision component. The second optical path completes the focusing and imaging of the calibration mark, obtains another coordinate information of the calibration mark, and obtains the coordinate information of the second detection mark relative to the calibration mark. (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 use this to obtain the compensation position coordinates of the chip to be attached when the two chips are aligned. (6) Control the plane adjustment module to work according to the compensation position coordinates to accurately align the chip to be bonded with the target chip; then, control the second displacement mechanism to work, and the bonding head will drive the chip to be bonded down to complete its bonding with the target chip.

Images