Wafer bonding equipment and wafer bonding method

Abstract

The invention discloses wafer bonding equipment and a wafer bonding method, and belongs to the technical field of wafer processing, the wafer bonding equipment comprises a plurality of visual assemblies based on infrared detection, and the visual assemblies are bonded by utilizing the combined arrangement of two displacement mechanisms and the preferable design of the bonding assemblies. According to the method, the two metal Marks on the to-be-pasted chip and the target chip can be imaged on the same infrared camera at the same time through the same visual assembly, multiple sets of mark point positions are detected at the same time through the multiple visual assemblies, and therefore the relative position relation between the to-be-pasted chip and the target chip is accurately obtained; and on the basis, rapid and accurate alignment before bonding of the target chip and the to-be-bonded chip is completed. The wafer bonding equipment is compact in structure and convenient to use, rapid alignment before chip bonding can be achieved, the frequent alignment and correction process of multiple sets of positioning assemblies is avoided, the alignment precision of the to-be-bonded chip and the target chip before bonding is guaranteed, the quality of chip bonding machining is improved, and the reject ratio of chip machining is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer processing, and in particular relates to a wafer bonding device and a wafer bonding method. Background Art

[0002] Bonding technology is a technology that uses van der Waals forces to tightly combine two homogeneous or heterogeneous wafers to achieve electrical interconnection, functional integration and device packaging of micro-electromechanical components such as microelectronic materials, optoelectronic materials and nanomaterials. The components made by it often have the advantages of direct metal interconnection, less heat, low power consumption and short delay. Therefore, it is widely used in the fields of RF devices, inertial devices, optoelectronic devices, information processing devices and 3D integrated logic integrated circuit packaging.

[0003] Bonding technology is widely used in the field of wafer processing and plays a very important role in the chip bonding process. During the wafer bonding process, the bonding objects need to be accurately aligned to ensure the accuracy of the chip bonding process. At present, for the alignment in the wafer bonding process, most of them need to set up a separate alignment component. The alignment operation is first completed by the alignment component, and then the bonding component is controlled to move into place according to the alignment result to complete the bonding process. Although this method can meet the needs of pre-bonding alignment to a certain extent, both the alignment component and the bonding component need to perform additional mechanical displacement processes before bonding, which can easily introduce new alignment errors. Moreover, the above method is greatly affected by temperature and vibration. When the working environment changes, the accuracy of the bonding alignment will also be affected, resulting in fluctuations in the accuracy of the bonding process, which has obvious limitations. Summary of the invention

[0004] In response to one or more of the above defects or improvement needs of the prior art, the present invention provides a wafer bonding device and a wafer bonding method, which can accurately achieve the accurate alignment of the target chip on the wafer and the chip to be attached before bonding, ensure the quality of wafer bonding, improve the quality of chip bonding processing, and reduce the defective rate of products.

[0005] To achieve the above object, the present invention provides a wafer bonding device and a wafer bonding method, comprising: A bonding assembly, comprising a bonding head for taking out the chip to be mounted, the bonding head being connected to a plane adjustment module, the plane adjustment module being used to drive the bonding head to perform XYθ adjustment within a plane; A bonding platform, which is used to carry a target chip to be bonded to the chip to be attached; A first displacement mechanism and a second displacement mechanism; the plane adjustment module is mounted on the second displacement mechanism, and the bonding head can be moved closer to or away from the bonding table under the drive of the second displacement mechanism; the second displacement mechanism is mounted on the first displacement mechanism, and can be horizontally displaced under the drive of the first displacement mechanism; At least two visual components, the visual components include an infrared camera module, the infrared camera module has an infrared light source for emitting infrared light and an infrared camera for focusing and imaging the infrared light; the optical path of the infrared light emitted from the visual component lens is perpendicular to the chip to be tested and the target chip which are parallel to each other; and The lenses of the bonding head corresponding to each visual component are respectively provided with alignment through holes; the infrared light emitted by the lenses of each visual component is respectively emitted to the first mark point on the chip to be attached and the second mark point on the target chip after penetrating the alignment through hole and the chip to be attached; both mark points are metal marks, and the infrared light forms two detection light paths after irradiating the two metal marks; and a glass lens is provided in the alignment through hole, and the detection light path of the first mark point is imaged on the infrared camera at the same time after passing through the glass lens and the other detection light path that does not pass through the glass lens; the glass lens satisfies: d =H1 / ( n -1) In the formula, d is the thickness of the glass lens; H1 is the distance between the target chip and the chip to be mounted in the direction of the optical path; n is the refractive index of the glass lens.

[0006] As a further improvement of the present invention, the spectrum range of the infrared light is between 1100nm and 1345nm.

[0007] As a further improvement of the present invention, each displacement mechanism includes a guide rail and a motor mounted on the guide rail; and the guide rail of the second displacement mechanism is connected to the motor of the first displacement mechanism and can follow it for horizontal displacement; and the plane adjustment module is connected to the motor of the second displacement mechanism and can follow it for lifting and lowering displacement.

[0008] As a further improvement of the present invention, a fixing plate is connected to the motor of the first displacement mechanism, and the at least two visual components and the guide rail of the second displacement mechanism are simultaneously mounted on the fixing plate.

[0009] As a further improvement of the present invention, the visual components are two respectively arranged on both sides of the bonding component, and are used for detecting the marking points at both ends of the chip to be attached; and / or The setting size of the glass lens is not greater than half of the cross-sectional area of ​​the alignment through hole.

[0010] As a further improvement of the present invention, the bottom surface of the bonding head is a working surface, and a plurality of negative pressure adsorption holes are provided on the working surface, so as to realize the adsorption and material extraction of the chip to be bonded by means of negative pressure adsorption.

[0011] As a further improvement of the present invention, the infrared camera module in the visual component is staggered with the lens of the visual component, and a reflector group is arranged between the infrared camera module and the lens; the reflector group includes at least one reflector.

[0012] As a further improvement of the present invention, the reflector group includes a first reflector and a second reflector that are spaced apart in the horizontal direction; The two reflectors are arranged at 45 degrees to the horizontal plane, and are used to reflect the detection light path from the infrared camera module from the vertical to the horizontal, and finally reflect it back to the vertical detection light path.

[0013] Another aspect of the present invention further provides a wafer bonding method, which is implemented using the wafer bonding device, and includes the following process: (1) Controlling the bonding head to complete the material collection of the chip to be bonded; (2) controlling the movement of the first displacement mechanism to drive the bonding head to a position above the corresponding target chip; (3) Controlling each visual component to work separately, and each visual component performs infrared focusing imaging on a pair of first marking points and second marking points respectively, to obtain imaging information of multiple groups of marking points; (4) Processing the imaging information of the multiple groups of marking points to obtain the relative position relationship between the two chips and obtain the XYθ adjustment information of the chip to be mounted; thereafter, controlling the plane adjustment module to work to accurately align the chip to be mounted with the target chip; (5) Control the second displacement mechanism to work, press the chip to be attached down to the surface of the target chip, and complete the bonding of the two chips.

[0014] As a further improvement of the present invention, during the process of picking up the chip to be mounted, a pre-alignment process of the chip to be mounted and the bonding head is performed to ensure that each alignment through hole is aligned with the first marking point on the chip to be mounted; and / or When the chip to be mounted is driven by the first displacement mechanism to the top of the target chip, a pre-alignment process is performed between the chip to be mounted and the target chip.

[0015] The above-mentioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0016] 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 of the present invention includes multiple vision components based on infrared detection. By utilizing the combination of two displacement mechanisms and the optimal design of the bonding component, the same vision component can simultaneously realize the simultaneous imaging of two metal marks on the chip to be bonded and the target chip on the same infrared camera. The multiple vision components simultaneously detect multiple groups of marking points, thereby accurately obtaining the relative position relationship between the chip to be bonded and the target chip, and based on this, quickly and accurately aligning the target chip with the chip to be bonded before bonding, thereby simplifying the control process when aligning the chip to be bonded with the target chip, improving the efficiency and accuracy of the alignment and bonding of the chip to be bonded with the target chip, and reducing the defect rate of the chip bonding process.

[0017] (2) The wafer bonding method of the present invention is implemented by using a wafer bonding device with a preferred design, has simple steps and convenient control, and can fully simplify the alignment process before the chip to be bonded with the target chip, thereby improving the efficiency of chip alignment and wafer bonding and reducing the cost of chip bonding processing.

[0018] (3) The wafer bonding equipment in the present invention has a compact structure and is easy to use. It can simultaneously realize imaging detection of metal marks on the chip to be bonded and the target chip based on dual-focus imaging, and represent the mark information at different heights in the same plane, thereby avoiding the frequent alignment and correction process of multiple sets of positioning components, 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. It has good practical value and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 is a schematic diagram of the overall structure of a wafer bonding device in an embodiment of the present invention; Figure 2 is a schematic diagram of the optical path design of the 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. First displacement mechanism; 3. Second displacement mechanism; 4. First visual assembly; 5. Second visual assembly; 6. Chip to be bonded; 7. Target chip; 8. Wafer; 9. Bonding station; 101. bonding head; 102. plane adjustment module; 103. alignment through hole; 201, translation motor; 202, translation guide rail; 203, fixing plate; 301, lifting motor; 302, lifting guide rail; 401, infrared camera module; 402, first reflector; 403, second reflector; 404, glass lens; 601, first marking point; 602, first pair of points; 701, second marking point; 702, second pair of points. DETAILED DESCRIPTION

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] Example: See also Figure 1~Figure 2 The wafer bonding equipment in the preferred embodiment of the present invention is suitable for the field of wafer chip bonding. In this field, it is necessary to bond the chip to be attached 6 with the target chip 7 on the wafer 8, and the target chips 7 on the wafer 8 are often arranged in an array. The bonding equipment needs to take the chips to be attached 6 in turn, and then bond the chips to be attached 6 tightly to the corresponding target chips 7.

[0027] Since the size of the chip to be attached 6 and the target chip 7 is extremely small, a very small mechanical error may cause misalignment between the chip to be attached 6 and the target chip 7, which ultimately leads to failure of the bonding process and the production of defective products. The wafer bonding equipment in the preferred embodiment of the present invention is designed to complete the alignment of the chip to be attached 6 and the target chip 7 on the wafer 8 before bonding, and ultimately achieve accurate bonding of the chip to be attached 6 and the target chip 7.

[0028] In actual setting, at least two pairs of positioning marks are set on the end faces of the chip to be mounted 6 and the target chip 7 for bonding, and the alignment process of the two chips is to achieve the alignment of the two pairs of positioning marks.

[0029] In more detail, the positioning marks on each chip are preferably arranged at the four corners of the chip, and more preferably are four pairs arranged at the four corners. For the chip to be mounted 6, each pair of positioning marks arranged on its bonding surface includes a first marking point 601 and a first pair of positions 602 arranged in pairs, and the two are arranged at a certain distance; correspondingly, each pair of positioning marks on the target chip 7 includes a second marking point 701 and a second pair of positions 702.

[0030] For the accurately aligned chip, the positioning marks of each part on the chip to be mounted 6 should be aligned with the positioning marks of the corresponding parts on the target chip 7. At this time, the first mark point 601 in the positioning mark is aligned with the second alignment point 702, and the first alignment point 602 is aligned with the second mark point 701. Figure 2 as shown in .

[0031] It can be understood that, for the two chips after alignment, the first marking point 601 and the second marking point 701 are offset in the vertical direction.

[0032] In more detail, in a preferred embodiment, the first marking point 601 on the chip to be attached 6 and the second marking point 701 on the target chip 7 are both set as metal marks, and the bonding device in the preferred embodiment is to achieve alignment of the two metal marks with the corresponding positions.

[0033] Specifically, the bonding device in the preferred embodiment includes a bonding component 1, a first displacement mechanism 2 and a second displacement mechanism 3 assembled to each other, a first visual component 4 and a second visual component 5 arranged corresponding to the bonding component 1, and a bonding table 9 for carrying a wafer 8 to be bonded.

[0034] The bonding assembly 1 is mainly used to pick up the chip 6 to be attached, and complete the bonding operation of the chip 6 to be attached on the target chip 7 after picking up and aligning.

[0035] In actual setting, the bonding assembly 1 includes a bonding head 101 and a plane adjustment module 102. The bonding head 101 is assembled on the plane adjustment module 102 through a connecting shaft, and can be driven by the plane adjustment module 102 to perform XYθ adjustment within the plane, thereby changing the alignment state of the chip to be attached 6; accordingly, the bottom surface of the bonding head 101 is the working surface for taking out the chip to be attached 6.

[0036] Exemplarily, a plurality of negative pressure adsorption holes are provided on the bottom surface of the bonding head 101 in the preferred embodiment, which can realize the adsorption and material extraction of the chip to be bonded 6 by negative pressure adsorption, and ensure the reliable maintenance of the position state of the chip to be bonded 6 during the bonding process.

[0037] Furthermore, in the preferred embodiment, the first displacement mechanism 2 comprises a translation guide rail 202 and a translation motor 201 mounted on the translation guide rail 202. The extension direction of the translation guide rail 202 is the horizontal direction, that is, Figure 1 By utilizing the reciprocating motion of the translation motor 201 on the translation guide rail 202 , the reciprocating motion control of the object mounted on the translation motor 201 in the X-axis direction can be realized.

[0038] In actual configuration, the second displacement mechanism 3 and the two visual components are simultaneously assembled and connected to the translation motor 201 , and can follow the translation motor 201 to perform reciprocating translation in the X-axis direction under the guidance of the translation guide rail 202 .

[0039] Exemplarily, the second displacement mechanism 3 and the first visual component 4 and the second visual component 5 in the preferred embodiment are simultaneously connected to a fixed plate 203 connected to a translation motor 201, and the translation motor 201 drives the fixed plate 203 to move back and forth, and then the fixed plate 203 drives the components arranged on the plate body to move back and forth in the X-axis direction.

[0040] More specifically, the second displacement mechanism 3 in the preferred embodiment includes a lifting rail 302 and a lifting motor 301 disposed on the lifting rail 302. At the same time, the bonding head 101 is connected to the lifting motor 301 through the plane adjustment module 102, and the lifting and reciprocating motion of the bonding head 101 can be realized through the reciprocating motion of the lifting motor 301 on the lifting rail 302, that is, Figure 1 The reciprocating movement on the Z axis is shown in .

[0041] Correspondingly, by controlling the plane adjustment module 102 , the relative position adjustment of the bonding head 101 with respect to the lifting motor 301 , ie, XYθ adjustment within the plane, can also be achieved.

[0042] Based on the combined setting of the two displacement mechanisms and the plane adjustment module 102, it is possible to achieve coarse adjustment of the plane displacement of the bonding head 101 in the X-axis direction (completed by the first displacement mechanism 2) and fine adjustment of XYθ within the plane (completed by the plane adjustment module 102), and after completing the adjustment of the plane position, the second displacement mechanism 3 realizes displacement adjustment in the Z-axis direction to complete the bonding process after the two chips are aligned.

[0043] More specifically, in the preferred embodiment, the structures of the two visual components are preferably arranged in the same manner, and the pre-bonding alignment of different parts of the two chips is completed based on the same working principle.

[0044] In such Figure 1 In the preferred embodiment shown, the two visual components are preferably spaced apart in the X-axis direction, such as Figure 1 As shown in , they are arranged on both sides of the second displacement mechanism 3. At this time, the two visual components are respectively used to align the two pairs of positioning marks arranged at intervals along the X-axis direction on the chip to be mounted 6.

[0045] Of course, it is understandable that the two visual components may be arranged in other forms according to the requirements of the setting.

[0046] For example, in a specific preferred embodiment, two pairs of positioning marks at diagonal positions of the chip 6 to be mounted are aligned. At this time, the two visual components are staggered and spaced in the X-axis direction.

[0047] For example, in another specific preferred embodiment, two pairs of positioning marks located on one side of the chip 6 to be attached in the X-axis direction are aligned. At this time, the two pairs of positioning marks are spaced apart on the Y-axis, and the two visual components are arranged on the same side of the bonding component 1 and spaced apart in the Y-axis direction.

[0048] Of course, in addition to setting two visual components, three or four visual components can also be set for the alignment of the two chips to achieve simultaneous positioning of the three or four corners of the two chips to ensure the accuracy of the alignment of the two chips.

[0049] In more detail, the visual components in the preferred embodiment are as follows Figure 1 , Figure 2 As shown in , it includes an infrared camera module 401, and the infrared camera module 401 includes an infrared light source and an infrared camera. The infrared light source is used to generate infrared light of a certain band, and the infrared light is reflected after being irradiated on the object to be detected to form a detection light path, and finally the infrared camera focuses on the detection light path to form an image, thereby completing the detection of the corresponding object.

[0050] In a preferred embodiment, the optical paths of the two detection light paths in the visual component are the same, they are incident in parallel from the lens of the visual component, and are imaged on the infrared camera at the same time.

[0051] Furthermore, the lens of the visual component is arranged directly above the corresponding position of the bonding head 101, and corresponding to the field of view of the lens, a positioning through hole 103 is opened vertically (along the Z-axis direction) on the bonding head 101, so that the infrared light emitted from the lens can be simultaneously emitted to the two marking points on the two chips after passing through the corresponding positioning through hole 103, and complete the detection and shooting of the metal marks (i.e., the first marking point 601 and the second marking point 701) on the chip to be bonded 6 and the target chip 7 under the bonding head 101 at the infrared camera.

[0052] In actual settings, in order to facilitate the combined setting of the visual component and the bonding component 1, the infrared camera module 401 in the preferred embodiment is arranged on one side of the bonding component 1, and the two infrared detection light paths it can receive extend along the Z axis; at the same time, a pair of reflectors is arranged corresponding to the infrared camera module 401, namely the first reflector 402 and the second reflector 403. The two detection lights formed by the reflection of the two metal marks are reflected by the second reflector 403 and the first reflector 402 and then focused and imaged by the infrared camera in the infrared camera module 401.

[0053] By using the corresponding arrangement of the two reflectors, the lens of the visual component and the infrared camera module 401 can be arranged in a staggered manner to adapt to the current situation where the device layout space above the bonding head 101 is limited.

[0054] For example, in a specific preferred embodiment, the two reflectors are arranged at 45° to the horizontal plane. At this time, the second reflector 403 can reflect the vertical light beam into a horizontal light beam, and the first reflector 402 can convert the horizontal light beam into a vertical light beam again. Figure 1 In more detail, the two reflectors are spaced apart in the X-axis direction, and the second reflector 403 is located directly above the visual component lens in the Z-axis direction. At this time, the infrared camera module 401 and the lens are staggered in the XZ plane.

[0055] At the same time, in order to accurately realize the transmission of infrared detection light to the chip to be attached 6 and the recognition of the metal mark, the spectrum range of the infrared light emitted by the infrared camera module 401 in the preferred embodiment is between 1100nm and 1345nm.

[0056] At the same time, the focusing optical path of the infrared camera module 401 is preferably set corresponding to the position of the target chip 7. At this time, the infrared light used for detection penetrates the alignment through hole 103 and the chip to be attached 6 and then shoots toward the first marking point 601 and the second marking point 701, and forms two detection optical paths through reflection of the two marking points (the metal Mark does not transmit the infrared light), and uses the focusing imaging of the two detection optical paths on the infrared camera to complete the detection of the positions of the two metal marks.

[0057] However, since there is a distance H1 between the chip to be attached 6 and the target chip 7, if you want to achieve simultaneous focusing imaging of the two detection light paths on the same infrared camera, you need to shorten the focusing optical path of the detection light path at the first marking point 601 to compensate for the distance H1 between the two chips.

[0058] In order to realize the above process, in a preferred embodiment, a glass lens 404 is provided in the alignment through hole 103, and the glass lens 404 can correspond to the chip to be mounted 6 in the Z-axis direction after the chip is picked up, so as to ensure that the detection beam formed by the first marking point 601 can complete the optical path reduction after passing through the glass lens 404; accordingly, the detection beam of the second marking point 701 does not pass through the glass lens 404. At the same time, in order to ensure the accuracy of the focus of the first marking point 601, the optical path reduced by the glass lens 404 is equal to the vertical spacing H1 between the two chips, that is, the thickness of the glass lens 404 d Meet the following requirements: d =H1 / ( n -1) In the formula, d is the thickness of the glass lens 404; H1 is the distance between the target chip 7 and the chip to be attached 6 in the optical path direction (ie Figure 2 The spacing in the Z-axis direction; n is the refractive index of the glass lens 404.

[0059] In more detail, the size of the glass lens 404 in the preferred embodiment is smaller than the cross-sectional area of ​​the alignment through hole 103, and ensures that one of the two detection light paths always passes through the glass lens 404, and the other directly passes through the alignment through hole 103 from the outside of the glass lens 404. In this way, it is ensured that two detection light paths with different actual optical paths can be obtained, but can be imaged simultaneously on the same infrared camera, so that two marking points can be imaged simultaneously on the infrared camera.

[0060] In actual configuration, the size of the glass lens 404 is no larger than half of the cross-sectional area of ​​the alignment through hole 103 .

[0061] For example, in a specific preferred embodiment, the size of the glass lens 404 is exactly half of the cross-sectional area of ​​the alignment through hole 103, and is further preferably located on one side of the inner side of the alignment through hole 103 in the X-axis direction, such as Figure 2 as shown in .

[0062] By using the visual component to simultaneously image the two metal Marks on the two chips, the relative position relationship of the local areas of the two chips can be accurately obtained. By processing the image (for example, determining the center of the metal Mark image, etc.), it can be determined whether the relative position between the chip to be attached 6 and the target chip 7 needs to be adjusted in the XY plane. At the same time, combined with the judgment of the detection result of another visual component, it can be determined whether the chip to be attached 6 needs to be adjusted in the XY plane.

[0063] That is, by combining the focus imaging of the two visual components, the corresponding detection of the metal mark positions on the two chips can be realized, and by controlling the plane adjustment module 102, the XYθ adjustment of the to-be-attached chip 6 in the plane before the two chips are bonded can be accurately completed, so as to realize the alignment of each mark point on the two chips with the corresponding alignment point, thereby realizing the precise alignment of the two chips before bonding. From then on, by controlling the second displacement mechanism 3 to move in the Z axis and controlling the stroke of the bonding head 101 to press down H1, the accurate bonding of the two chips can be completed.

[0064] It should be noted that when the bonding equipment performs bonding operations, the bonding component 1 needs to undergo at least two processes: material extraction (extracting the chip to be attached 6) and displacement (moving the chip to be attached 6 from the material extraction position to the top of the target chip 7), and both processes are completed under precise control, that is, when the bonding head 101 absorbs the chip to be attached 6, each first mark point 601 on the chip to be attached 6 has a relatively accurate alignment relationship with each alignment through hole 103 on the bonding head 101, and there will be no situation where the first mark point 601 and the glass lens 404 do not correspond vertically. Moreover, after moving to the top of the target chip 7, there will be no situation where the second mark point 701 deviates from the infrared detection light detection field of view.

[0065] In short, the bonding device in the preferred embodiment is based on the combination of two visual components and a bonding component 1, aiming to achieve precise alignment of two chips to be bonded under a certain alignment accuracy. Through the corresponding work of the two visual 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.

[0066] Using the corresponding settings of the aforementioned wafer bonding device, a wafer bonding method is further proposed in a preferred embodiment of the present invention, which is implemented using the aforementioned wafer bonding device. The method includes the following process: (1) Driven by the first displacement mechanism 2, the bonding assembly 1 is driven to the material removal station and the chip to be bonded 6 is removed; At this time, the chip 6 to be attached that has completed the material removal is adsorbed on the bottom surface of the bonding head 101, and the first marking points 601 on the chip 6 to be attached are aligned with the glass lens 404 in the corresponding alignment through hole 103, and the first alignment point 602 corresponds to the through hole area outside the glass lens 404.

[0067] The alignment process between the chip to be attached 6 and the bonding head 101 can be achieved through a pre-alignment process, which can be achieved by setting up an additional alignment mechanism or through the detection of each visual component. For example, when taking the chip to be attached 6, multiple visual components are turned on at the same time to ensure that the first mark point 601 in each alignment through hole 103 is in focus.

[0068] It can be understood that in the above-mentioned pre-alignment process, each visual component and the bonding component 1 are synchronously displacement-controlled.

[0069] In addition to the above-mentioned pre-alignment method, the pre-alignment between the chip to be mounted 6 and the bonding head 101 can also be achieved through precise mechanical control. By presetting accurate stroke displacement parameters, the accuracy of the chip to be mounted 6 when taking out the material is ensured.

[0070] (2) Controlling the first displacement mechanism 2 to drive the bonding component 1 and the two visual components to synchronously move in the X-axis direction, and to drive the chip to be bonded 6 to the top of the corresponding target chip 7, wherein the target chip 7 is arranged on the corresponding wafer 8, and the wafer 8 is carried on the bonding table 9; As above, when the first displacement mechanism 2 is controlled, a pre-alignment process between the target chip 7 and the chip to be attached 6 is also performed. This process can be completed by precise mechanical control or by pre-operation of at least one visual component, which will not be elaborated here.

[0071] (3) Controlling each visual component to work separately, each visual component generates infrared light to focus and image the first marking point 601 on the chip to be attached 6 and the second marking point 701 on the target chip 7, thereby obtaining multiple groups of marking points (for example Figure 1The two groups shown, each group of marking points includes imaging information of a first marking point 601 and a second marking point 701); (4) Processing the imaging information of the multiple groups of marking points to obtain the relative position relationship between the two chips, and then obtaining the XYθ adjustment information of the chip to be attached 6; thereafter, controlling the plane adjustment module 102 to work, adjusting the position of the chip to be attached 6 to be accurately aligned with the target chip 7 on the Z axis; (5) The second displacement mechanism 3 is controlled to work, and the chip to be attached 6 is pressed down along the Z axis to the surface of the target chip 7, thereby completing the bonding of the two chips.

[0072] The process in (1) to (5) is repeated to complete the bonding process between the plurality of chips to be bonded 6 and the corresponding target chips 7.

[0073] The wafer bonding equipment in the present invention has a compact structure and is easy to use. It can simultaneously realize imaging detection of the metal marks on the chip to be bonded and the target chip based on dual-focus imaging, and characterize the metal mark information at different heights in the same plane, thereby avoiding the frequent alignment and correction process of multiple groups of positioning components, 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.

[0074] 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, characterized in that: include: A bonding assembly, comprising a bonding head for taking out the chip to be mounted, the bonding head being connected to a plane adjustment module, the plane adjustment module being used to drive the bonding head to perform XYθ adjustment within a plane; A bonding platform, which is used to carry a target chip to be bonded to the chip to be attached; A first displacement mechanism and a second displacement mechanism; the plane adjustment module is mounted on the second displacement mechanism, and the bonding head can be moved closer to or away from the bonding table under the drive of the second displacement mechanism; the second displacement mechanism is mounted on the first displacement mechanism, and can be horizontally displaced under the drive of the first displacement mechanism; At least two visual components, the visual components include an infrared camera module, the infrared camera module has an infrared light source for emitting infrared light and an infrared camera for focusing and imaging the infrared light; the optical path of the infrared light emitted from the visual component lens is perpendicular to the chip to be tested and the target chip which are parallel to each other; and The lenses of the bonding head corresponding to each visual component are respectively provided with alignment through holes; the infrared light emitted by the lenses of each visual component is respectively emitted to the first mark point on the chip to be attached and the second mark point on the target chip after penetrating the alignment through hole and the chip to be attached; both mark points are metal marks, and the infrared light forms two detection light paths after irradiating the two metal marks; and a glass lens is provided in the alignment through hole, and the detection light path of the first mark point is imaged on the infrared camera at the same time after passing through the glass lens and the other detection light path that does not pass through the glass lens; the glass lens satisfies: d =H1 / （ n -1） In the formula, d is the thickness of the glass lens; H1 is the distance between the target chip and the chip to be mounted in the direction of the optical path; n is the refractive index of the glass lens.

2. The wafer bonding equipment according to claim 1, characterized in that: The spectral range of the infrared light is between 1100nm and 1345nm.

3. The wafer bonding equipment according to claim 2, characterized in that: Each displacement mechanism includes a guide rail and a motor mounted on the guide rail; the guide rail of the second displacement mechanism is connected to the motor of the first displacement mechanism and can follow it for horizontal displacement; and the plane adjustment module is connected to the motor of the second displacement mechanism and can follow it for lifting and lowering displacement.

4. The wafer bonding equipment according to claim 3, characterized in that: A fixing plate is connected to the motor of the first displacement mechanism, and the at least two visual components and the guide rail of the second displacement mechanism are simultaneously mounted on the fixing plate.

5. The wafer bonding equipment according to any one of claims 1 to 4, characterized in that: The visual components are two respectively arranged on both sides of the bonding component, and are used for detecting the marking points at both ends of the chip to be attached; and / or The setting size of the glass lens is not greater than half of the cross-sectional area of ​​the alignment through hole.

6. The wafer bonding equipment according to any one of claims 1 to 4, characterized in that: The bottom surface of the bonding head is a working surface, and a plurality of negative pressure adsorption holes are provided on the working surface, and negative pressure adsorption is used to realize adsorption and material extraction of the chip to be bonded.

7. The wafer bonding equipment according to any one of claims 1 to 4, characterized in that: The infrared camera module in the visual component is staggered with the lens of the visual component, and a reflector group is arranged between the infrared camera module and the lens; the reflector group includes at least one reflector.

8. The wafer bonding equipment according to claim 7, characterized in that: The reflector group includes a first reflector and a second reflector that are spaced apart in the horizontal direction; The two reflectors are arranged at 45 degrees to the horizontal plane, and are used to reflect the detection light path from the infrared camera module from the vertical to the horizontal, and finally reflect it back to the vertical detection light path.

9. A wafer bonding method, which is implemented by using the wafer bonding device according to any one of claims 1 to 8, characterized in that: The process includes the following: (1) Controlling the bonding head to complete the material removal of the chip to be bonded; (2) controlling the movement of the first displacement mechanism to drive the bonding head to a position above the corresponding target chip; (3) Controlling each visual component to work separately, and each visual component performs infrared focusing imaging on a pair of first marking points and second marking points respectively, to obtain imaging information of multiple groups of marking points; (4) Processing the imaging information of the multiple groups of marking points to obtain the relative position relationship between the two chips and obtain the XYθ adjustment information of the chip to be mounted; thereafter, controlling the plane adjustment module to work to accurately align the chip to be mounted with the target chip; (5) Control the second displacement mechanism to work, press the chip to be attached down to the surface of the target chip, and complete the bonding of the two chips.

10. The wafer bonding method according to claim 9, characterized in that: During the process of picking up the chip to be attached, a pre-alignment process is performed between the chip to be attached and the bonding head to ensure that each alignment through hole is aligned with the first marking point on the chip to be attached; and / or When the chip to be mounted is driven by the first displacement mechanism to the top of the target chip, a pre-alignment process is performed between the chip to be mounted and the target chip.

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