Wafer bonding magnetic array alignment method

Abstract

The application discloses a wafer bonding magnetic array alignment method, which comprises the following steps: a plurality of groups of magnetic array marks with geometric shape and symmetric distribution characteristics are made on a wafer by a MEMS method; the magnetic array marks are symmetrically distributed; a plurality of magnetic marks exist in each group of magnetic array; and the magnetic marks are equidistantly distributed. A plurality of groups of magnetic sensor arrays with symmetric distribution characteristics are pre-embedded in a clamping and bearing mechanism by a MEMS method; a plurality of magnetic sensors exist in each group of magnetic sensor array; and the magnetic sensors in each group of magnetic sensor array are equidistantly distributed. The magnetic field distribution information generated by the corresponding magnetic marks is collected by each magnetic sensor array in real time, the spatial position information of each magnetic mark is acquired, and the spatial posture information of the wafer is acquired through the symmetric distribution characteristics of the magnetic array and the magnetic sensor array. The application improves the information density of the magnetic field distribution, enhances the processing capacity of the magnetic information, and improves the efficiency and precision of wafer alignment and bonding.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor packaging, and relates to a wafer bonding alignment method, in particular to a wafer bonding magnetic array alignment method. BACKGROUND

[0002] Semiconductor devices are an important part of modern electronic industry, and semiconductor packaging technology plays a very important role in the semiconductor industry in improving the performance of semiconductor devices, increasing reliability, providing device protection and other important features. With the emergence of new applications such as 5G, wearable devices and new demands such as miniaturization of electronic devices, semiconductor packaging technology is also rapidly growing and gradually maturing. Among them, wafer-level advanced packaging is a crucial research and application direction to achieve beyond Moore's Law. Wafer-level bonding equipment integrates multiple functional units, and realizes the complete process of wafer activation, cleaning, alignment, pre-bonding and verification inside the equipment. Due to its important strategic value, many well-known enterprises, universities and research institutes at home and abroad have launched research around wafer-level packaging.

[0003] Wafer-level bonding refers to high-precision alignment, bonding and bonding of two wafers through a process to produce a certain interfacial bonding strength of the two wafers. The process of bonding is generally: pre-treatment, cleaning, visual alignment of wafer groups, and specific process methods to realize the bonding of paired wafers. In this process, the alignment precision of wafer-level is a very difficult challenge. The general wafer alignment system needs to identify and position the image of the wafer, evaluate the positioning error through the positioning error between the optical marks pre-set on the wafer, and cooperate with the motion control system to eliminate the positioning error. As can be seen, the wafer alignment system is complex and delicate, and generally involves mechanical design, camera system, motion control, image algorithm and other fields. Among them, the cost of high-level image processing unit and its integration difficulty in wafer bonding equipment are becoming higher and higher, which limits the processing of optical images, thereby limiting the further improvement of the wafer-level alignment precision.

[0004] Among the existing wafer alignment methods, Liu Yang of Wuhan Xinxin Integrated Circuit Manufacturing Co., Ltd. applied for a Chinese patent CN201811103353.9, which discloses a wafer bonding and method and device. A double-chuck, double-camera structure is adopted, and the wafer pair is placed on the two chucks. The double-camera system is used to identify the mark pattern on the back of the chuck device carrying the wafer, and the position error between the two chucks is obtained. By analyzing the recorded position of the wafer on the chuck, the wafer pair is indirectly aligned by aligning the two chucks. This method is an indirect alignment method, and the precision is difficult to guarantee, and the structure is complex, and the implementation is difficult. Chen Xing et al. of Rui Li Scientific Instruments (Shanghai) Co., Ltd. applied for a Chinese patent CN201410148217.7, which discloses a wafer alignment system and a wafer alignment method. The system needs at least four cameras to cover the image features of the two opposite corners of the wafer with a limited positioning gap and the remaining edges. A sufficient number of cameras are used to obtain a large enough field of view to cover the transmission error of the wafer. This invention does not need to set alignment marks on the wafer, but needs to couple multiple camera pictures through a multi-image acquisition card. The optical structure, image algorithm and mechanical structure are complex, the implementation is difficult, and the complex system will lead to reduced precision. Ye Lezhi et al. of Beijing University of Technology applied for a Chinese patent CN202210174134.X, which discloses a wafer bonding and alignment method and device. The device inserts a magnetic sensor between the two wafers to detect the spatial magnetic field distribution generated by the pre-set permanent magnetic column on the wafer, finds the boundary or center of the magnetic column, and thus realizes the detection of the wafer position information. The device reduces the Z-direction stroke of wafer bonding to a certain extent, but only uses a single magnetic sensor to detect the magnetic field generated by the isolated magnetic column, and the precision is low. SUMMARY

[0005] The application provides a wafer bonding magnetic array alignment method. The method is characterized in that a plurality of groups of magnetic array markers with geometric shape and symmetric distribution characteristics are made on the wafer by MEMS. The magnetic array markers are symmetrically distributed, and a plurality of magnetic markers exist in each group of magnetic array, and the magnetic markers are equidistantly distributed. A plurality of groups of magnetic sensor arrays with symmetric distribution characteristics are pre-embedded in the clamping and bearing mechanism by MEMS. A plurality of magnetic sensors exist in each group of magnetic sensor array, and the magnetic sensors in each group of magnetic sensor array are equidistantly distributed. The number of magnetic array markers is greater than or equal to the number of magnetic sensor arrays, the number of magnetic markers is less than or equal to the number of magnetic sensors, and each magnetic marker is covered under the corresponding magnetic sensor array. Each magnetic marker penetrates the wafer or is made on one side of the wafer, and the exposed surface of the magnetic marker faces the clamping mechanism or the bearing mechanism. Each magnetic sensor is made on the surface of the clamping mechanism or the bearing mechanism, is exposed on the surface of the mechanism and faces the wafer. Each magnetic sensor array collects the magnetic field distribution information generated by the corresponding magnetic marker in real time, obtains the spatial position information of each magnetic marker, and obtains the spatial attitude information of the wafer through the symmetric distribution characteristics of the magnetic array and the magnetic sensor array. When two or more wafers are stacked, the spatial vector error of the two or more wafers is obtained. The spatial vector error is eliminated by a motion system, and alignment is completed. After alignment, the two wafers are bonded.

[0006] In order to achieve the above-mentioned purpose, the wafer bonding magnetic array alignment method provided by the application comprises the following steps:

[0007] A) The bearing mechanism and the clamping mechanism are close to each other along the vertical direction in the unloaded state, or the bearing mechanism and the clamping mechanism, or the bearing mechanism and the correction sheet, or the clamping mechanism and the correction sheet, perform mechanism self-correction and draw the magnetic field environment.

[0008] B) Further, the bearing mechanism sends the first wafer to the first preset position, and the bearing mechanism and the clamping mechanism are respectively arranged on both sides of the first wafer. The plurality of magnetic sensor arrays and the plurality of magnetic array markers of the first wafer are in a corresponding relationship at the first preset position, and any magnetic array marker cannot be completely placed outside the coverage range of the magnetic sensor array. Then the clamping mechanism keeps the first wafer to the second preset position.

[0009] C) Further, the magnetic sensor array obtains the magnetic field distribution information generated by the magnetic array marker column of the first wafer at the second preset position, obtains the relative position information of the first wafer, and further obtains the absolute position information of the first wafer.

[0010] D) further, the carrying mechanism sends the second wafer to a first preset position, the carrying mechanism is placed under the second wafer, the first wafer is held by the clamping mechanism in a second preset position, and the carrying mechanism is placed on the second wafer. Any magnetic array mark cannot be completely placed outside the coverage range of the magnetic sensor array.

[0011] E) further, the magnetic sensor array simultaneously obtains magnetic field distribution information generated by the first wafer magnetic array mark and the second wafer magnetic array mark, obtains the relative position information of the second wafer, and further obtains the absolute position information of the second wafer.

[0012] F) further, according to the absolute position information of the first wafer and the second wafer, the spatial vector error information of the first wafer and the second wafer is obtained. The clamping mechanism drives the first wafer to fine-tune alignment.

[0013] G) further, the position of the clamping mechanism after fine-tuning is set as a third preset position. The operation of E is repeated until the spatial vector error of the first wafer and the second wafer is less than a preset tolerance limit.

[0014] H) further, the first wafer is close to the second wafer in the vertical direction under the holding of the clamping mechanism, and the bonding process is completed.

[0015] Preferably, when the absolute position information of the first wafer and the second wafer is obtained, the warping of the wafer is obtained, and whether it exceeds the preset tolerance limit is checked.

[0016] Preferably, the first preset position and the second preset position can be corrected by a correction sheet.

[0017] Preferably, in the preset position, each magnetic mark in the magnetic array mark is under the coverage range of the corresponding magnetic sensor array.

[0018] Preferably, in the step F, the first wafer and the second wafer are parallel, and the distance between the first wafer and the second wafer is less than the thickness of a wafer.

[0019] Compared with the traditional optical alignment method, the Z direction stroke is extremely small, the system stiffness is large, and the system itself can always correct itself, without the need for external correction to eliminate the error caused by the system itself. Compared with the disclosed magnetic alignment method, the magnetic array mark and the magnetic sensor array are used in the application, which greatly improves the information density of the magnetic field distribution and greatly enhances the processing capacity of the magnetic information. The efficiency and precision of wafer alignment and bonding are improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1is a schematic diagram of a magnetic array mark and the distribution of the magnetic mark in the magnetic array mark made by MEMS method on a first wafer in an embodiment of the present application.

[0021] Figure 2 is a schematic diagram of a magnetic array mark and the distribution of the magnetic mark in the magnetic array mark made by MEMS method on a second wafer in an embodiment of the present application.

[0022] Figure 3 is a schematic diagram of a magnetic sensor array and the distribution of the magnetic sensor in the magnetic sensor array made by MEMS method in a holding mechanism of the present application.

[0023] Figure 4 is a schematic diagram of a magnetic sensor array and the distribution of the magnetic sensor in the magnetic sensor array made by MEMS method in a bearing mechanism of the present application.

[0024] Figure 5 is a flow chart of a wafer bonding magnetic array alignment algorithm in an embodiment of the present application.

[0025] Figure 6 is a flow chart of a wafer bonding magnetic array alignment method in an embodiment of the present application.

[0026] Figure 7 is a schematic diagram of the working process of the implementation process of a wafer bonding magnetic array alignment method in an embodiment of the present application.

[0027] Figure 8 is a spatial magnetic field distribution generated by a part of magnetic marks in a group of magnetic array marks detected by a group of magnetic sensor arrays in an embodiment of the present application.

[0028] In the figure: 10-first wafer; 101-first wafer magnetic array mark; 102-first wafer magnetic mark; 20-second wafer; 201-second wafer magnetic array mark; 202-second wafer magnetic mark; 30-holding mechanism; 301-holding mechanism vacuum suction hole; 302-holding mechanism magnetic sensor array; 303-holding mechanism magnetic sensor; 40-bearing mechanism; 401-bearing mechanism vacuum suction hole; 402-bearing mechanism magnetic sensor array; 403-bearing mechanism magnetic sensor; 50-planner. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the accompanying drawings of the embodiments. The advantages and features of the present application will be more apparent according to the following description. It should be noted that the accompanying drawings are very simplified and use non-precise proportions, only to facilitate, clarify the purpose of assisting the description of the embodiments of the present application.

[0030] Figure 1This is a schematic diagram of a first wafer and a magnetic array marker fabricated on the wafer using MEMS, illustrating the distribution of the magnetic markers, according to an embodiment of the present invention. Exemplarily, a plurality of magnetic array markers 101 are distributed on the first wafer 10. Each magnetic array marker 101 is composed of a plurality of magnetic markers 102 fabricated using MEMS. Each magnetic marker 102 is partially embedded in the wafer surface, with its top horizontal to the wafer surface and its bottom embedded inside the wafer. The edges of each magnetic marker 102 at an edge position of each magnetic array marker 101 constitute the edge of each magnetic array marker 101. The plurality of magnetic array markers 101 are periodically distributed in a symmetrical or equidistant manner. The plurality of magnetic markers 102 are periodically distributed in a symmetrical or equidistant manner. In this example, 16 magnetic array markers 101 form a magnetic array, the edge shape of which is square, and the area covered by the magnetic array is smaller than the inscribed rectangle of the wafer.

[0031] Figure 2 This is a schematic diagram illustrating the second wafer of the present invention, the magnetic array markers fabricated on the wafer using MEMS, and the distribution of the magnetic markers. For example,... Figure 1 and Figure 2 As shown, the second wafer 20 has a structure similar to that of the first wafer 10. The magnetic array markers 201 of the second wafer 20 are correspondingly arranged with the magnetic array markers 101 of the first wafer 10. The magnetic markers 202 in the magnetic array markers 201 of the second wafer 20 are correspondingly arranged with the magnetic markers 102 in the magnetic array markers 101 of the first wafer 10. Correspondingly, the magnetic array coverage areas of the second wafer 20 and the first wafer 10 are the same.

[0032] Figure 3Figure 1 shows a schematic diagram of a clamping mechanism and a magnetic sensor array on the clamping mechanism made by MEMS method and the distribution of the magnetic sensors in the magnetic sensor array according to an embodiment of the present application. For example, the clamping mechanism 30 can move in the Z direction, and the clamping mechanism 30 is uniformly distributed with vacuum suction holes 301. The clamping mechanism is distributed with a plurality of magnetic sensor arrays 302, which are composed of a plurality of magnetic markers 303 made by MEMS method. Each magnetic sensor 303 is half-buried in the surface of the clamping mechanism 30, with the top of the magnetic sensor 303 being flush with the surface of the clamping mechanism 30 and the bottom being buried in the interior of the clamping mechanism. Each magnetic sensor array 302 of the clamping mechanism 30 is arranged in correspondence with each magnetic array marker 101 on the first wafer 10 and each magnetic array marker 201 on the second wafer 20. The edges of each magnetic sensor 303 at the edge position of each magnetic sensor array 302 form the edge of each magnetic sensor array 302. The edge coverage of each magnetic sensor array 302 is greater than the edge coverage of each corresponding magnetic array marker 101 or magnetic array marker 201, and the number of magnetic sensors 303 in each magnetic sensor array 302 is greater than the number of magnetic markers 102 or magnetic markers 202 in each corresponding magnetic array marker 101 or magnetic array marker 201.

[0033] Figure 4 Figure 2 shows a schematic diagram of a bearing mechanism according to an embodiment of the present application. For example, the bearing mechanism 40 can move in the X-Y direction, and the bearing mechanism 40 is uniformly distributed with a plurality of vacuum suction holes 401. In some examples, the bearing mechanism 40 is provided with magnetic array markers 402 and magnetic markers 403 corresponding to those on the clamping mechanism 30.

[0034] The alignment method should provide a bearing mechanism, a clamping device, a first wafer, a second wafer, and a planner.

[0035] Figure 5 and Figure 6 It is disclosed that the alignment method comprises the following steps:

[0036] A) The bearing mechanism and the clamping mechanism are moved closer to each other in the vertical direction in the unloaded state, or the bearing mechanism and the clamping mechanism, or the bearing mechanism and the correction sheet, or the clamping mechanism and the correction sheet, are subjected to mechanism self-correction and draw the magnetic field environment.

[0037] Specifically, the correction sheet can be replaced by any one of the first wafer or the second wafer, or a product similar in structure to the first wafer or the second wafer is prepared. If there is no first wafer or second wafer, and no correction sheet, the magnetic sensor array is also placed in the carrying mechanism. The magnetic sensor array in the carrying mechanism and the magnetic sensor array in the clamping mechanism are inductively verified with each other, the deviation of the distribution position of the magnetic sensor in the magnetic sensor array in each other from the manufacturing position in the mechanism is measured, the relative spatial position of each other is measured, and compensation and correction are made in the planning. The compensation and correction data include the influence of the environment. When there is an environmental change, especially an electromagnetic environmental change, this step is necessary.

[0038] B) Further, the carrying mechanism sends the first wafer to a first preset position, and the carrying mechanism and the clamping mechanism are respectively placed on both sides of the first wafer. The first preset position is in a corresponding relationship with the magnetic array markers of the first wafer. Any magnetic array marker cannot be completely placed outside the coverage range of the magnetic sensor array. Then the clamping mechanism holds the first wafer to a second preset position.

[0039] Specifically, the first wafer is parallel to the carrying mechanism. The first preset position is the position of the carrying mechanism after the carrying mechanism and the clamping mechanism are close to each other in the vertical direction and the deviation is corrected in step A. The uniformly distributed vacuum suction holes on the surface of the carrying mechanism ensure that the relative position between the carrying mechanism and the first wafer does not change when the carrying mechanism carries the first wafer. After the carrying mechanism carries the first wafer to the first preset position, the clamping mechanism moves along the Z axis to the position of the first wafer, contacts, and then determines the closing of the vacuum suction hole of the carrying mechanism according to the contact pressure, opens the vacuum suction hole of the clamping mechanism, and holds the first wafer to the second preset position. The second preset position is the position of the clamping mechanism after the carrying mechanism and the clamping mechanism are close to each other in the vertical direction and the deviation is corrected in step A.

[0040] C) Further, the magnetic sensor array obtains the magnetic field distribution information generated by the magnetic array marker column of the first wafer at the second preset position, obtains the relative position information of the first wafer, and further obtains the absolute position information of the first wafer. The magnetic field distribution information and the relative position information of the first wafer obtained at this time will be saved in the planner.

[0041] D) further, the carrier mechanism sends the second wafer to a first preset position, the carrier mechanism is placed under the second wafer, the first wafer is held by the clamping mechanism at a second preset position, and the carrier mechanism is placed on the second wafer. A plurality of magnetic sensor arrays in the first preset position are in a corresponding relationship with a plurality of magnetic array markers of the second wafer, and any magnetic array marker cannot be completely placed outside the coverage range of the magnetic sensor array. If any magnetic array marker is completely placed outside the coverage range of the magnetic sensor array, the carrier mechanism should be rotated, and each magnetic array marker should be placed outside the coverage range of the corresponding magnetic sensor array. If rotation still cannot achieve the effect, the A step should be re-executed.

[0042] E) further, the magnetic sensor array simultaneously obtains magnetic field distribution information generated by the first wafer magnetic array marker and the second wafer magnetic array marker, obtains the relative position information of the second wafer, and further obtains the absolute position information of the second wafer.

[0043] Specifically, according to the information of the first preset position and the second preset position, the first wafer and the second wafer are positioned between the carrier mechanism and the clamping mechanism. The position of each magnetic marker on the first wafer and the second wafer can be determined. And these information can be more accurately processed in the planner.

[0044] F) further, according to the absolute position information of the first wafer and the second wafer, the spatial vector error information of the first wafer and the second wafer is obtained. The clamping mechanism drives the first wafer to fine-tune the alignment.

[0045] Specifically, after obtaining the spatial vector error information between the first wafer and the second wafer, the carrier mechanism can make adjustments in the X-Y-rotation direction, so that the magnetic markers on the first wafer and the magnetic markers on the second wafer are aligned. In the process of fine-tuning, the vacuum suction nozzle of the carrier mechanism ensures that the relative position between the carrier mechanism and the second wafer does not deviate.

[0046] G) further, the position of the clamping mechanism after fine-tuning is set as a third preset position. Repeat the E step operation until the spatial vector error of the first wafer and the second wafer is less than the preset tolerance limit. The determination of the third preset position needs to go through multiple rapid fine-tuning.

[0047] H) further, the first wafer is held by the clamping mechanism, and is close to the second wafer in the vertical direction to complete the bonding process.

[0048] Next, the accompanying drawings will be described Figure 1 、 2, 3, 4, 7. The first step, the first wafer 10 is placed on the bearing mechanism 40, the vacuum suction hole 401 is opened. The holding mechanism 30 is lowered along the Z axis, and stops before contacting the first wafer 10. The first wafer 10 is regarded as a correction sheet, and the alignment system is self-corrected. The second step, the current position of the bearing mechanism 401 is regarded as the first preset position, and the current position of the holding mechanism 30 is regarded as the second preset position. At this time, each magnetic array mark 101 of the first wafer 10 is placed under the corresponding magnetic sensing array 402 of the bearing mechanism 40. The holding mechanism 30 continues to move downward along the Z axis until it contacts the first wafer 10, the vacuum suction hole 401 is closed, and the vacuum fine hole 301 is opened to suck up the first wafer 10 and return to the second preset position. At this time, each magnetic array mark 101 of the first wafer 10 is placed under the corresponding magnetic sensing array 302 of the holding mechanism 30. The magnetic sensing array 302 collects the magnetic information of the magnetic mark 102 collected by each magnetic sensor 303 and sends it to the planner 50, and the magnetic sensing array 402 collects the magnetic information of the magnetic mark 102 collected by each magnetic sensor 403 and sends it to the planner 50. The planner 50 calculates and saves the first wafer position information, saves the first preset position and the second preset position information, and saves the current magnetic field information. The third step, the bearing mechanism 40 exits from the first preset position, and the second wafer 20 is placed on the bearing mechanism 40, and the vacuum suction hole 401 is opened. The bearing mechanism 40 carries the second wafer 20 to the first preset position. At this time, each magnetic array mark 201 of the second wafer 20 is placed under the corresponding magnetic sensing array 402 of the bearing mechanism 40. The bearing mechanism 40 and the holding mechanism 20 sandwich the first wafer 10 and the second wafer 20. At this time, the top of each magnetic mark 102 in the first wafer 10 faces the top of each magnetic mark 202 in the second wafer 20. The magnetic sensing array 302 collects the magnetic information of the magnetic mark 202 collected by each magnetic sensor 303 and sends it to the planner 50, and the magnetic sensing array 402 collects the magnetic information of the magnetic mark 202 collected by each magnetic sensor 403 and sends it to the planner 50. The third step: the planner 50 calculates the position information of the second wafer 20 according to the stored information, calculates the spatial vector error between the first wafer 10 and the second wafer 20, and adjusts the X-Y-rotation direction according to the error. Then, in the planner, it is judged whether the error between each magnetic mark 102 in the first wafer 10 and the corresponding magnetic mark 202 is less than the tolerance limit. The fourth step, if the alignment accuracy requirement is met, subsequent operations such as bonding are performed. If the alignment accuracy requirement is not met, repeat the fine adjustment and judgment operation of the third step until the alignment accuracy requirement is met.

[0049] The application provides a wafer bonding magnetic array alignment method, magnetic array marks and magnetic marks are prepared on a wafer surface layer through MEMS technology, a magnetic sensor array and a sensor are prepared in a detection mechanism through MEMS technology, and the detection of wafer position information and the alignment between wafers are realized. Compared with a traditional optical alignment mode, the Z-direction stroke is extremely small, the system stiffness is large, and the system itself can be self-corrected at any time, and the error caused by the system itself can be eliminated without external correction. Compared with the disclosed magnetic alignment mode, the magnetic array marks and the magnetic sensor array are adopted, the information density of the magnetic field distribution is greatly improved, and the processing capacity of the magnetic information is greatly enhanced. The wafer alignment and bonding efficiency and precision are improved.

[0050] The above is the preferred embodiment of the application, it should be pointed out that, for the ordinary skilled in the art, without departing from the principles of the application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A method for aligning a wafer bonding magnetic array, characterized in that, This method involves fabricating several sets of magnetic array marks with geometrically shaped and symmetrically distributed characteristics on a wafer using MEMS. These sets of magnetic array marks are symmetrically distributed, with each array containing several magnetic marks, and each mark being equidistantly spaced. Multiple sets of symmetrically distributed magnetic sensing arrays are pre-embedded in the clamping and support mechanism using MEMS. Each magnetic sensing array contains several magnetic sensors, and these sensors are equidistantly spaced. The number of magnetic array marks is greater than or equal to the number of magnetic sensing arrays, and the number of magnetic marks is less than or equal to the number of magnetic sensors. Each magnetic mark covers a corresponding magnetic sensor array. Below; each magnetic marker penetrates the wafer or is fabricated on one side of the wafer, with the exposed surface of the magnetic marker facing the clamping mechanism or carrier mechanism; each magnetic sensor is fabricated on the surface of the clamping mechanism or carrier mechanism, exposed on the mechanism surface and facing the wafer; each magnetic sensor array collects the magnetic field distribution information generated by the corresponding magnetic marker in real time, obtains the spatial position information of each magnetic marker, and obtains the spatial orientation information of the wafer through the symmetrical distribution characteristics of the magnetic array and the magnetic sensor array; when two or more wafers are stacked, the spatial vector error of the two or more wafers is obtained; this spatial error is eliminated by the motion system and alignment is completed, and the two wafers are bonded after alignment; The method includes the following steps: A) The bearing mechanism and the clamping mechanism approach each other vertically in an unloaded state, or the bearing mechanism and the clamping mechanism, or the bearing mechanism and the correction plate, or the clamping mechanism and the correction plate, to perform mechanism self-calibration and draw the magnetic field environment. B) The carrier mechanism delivers the first wafer to the first preset position. The carrier mechanism and the clamping mechanism are respectively placed on both sides of the first wafer. At the first preset position, several magnetic sensor arrays correspond to several magnetic array marks on the first wafer. No magnetic array mark is completely outside the coverage of the magnetic sensor array. The clamping mechanism holds the first wafer to the second preset position. C) The magnetic sensing array acquires the magnetic field distribution information generated by the first wafer magnetic array marker column at the second preset position, obtains the relative position information of the first wafer, and obtains the absolute position information of the first wafer; D) The carrier mechanism delivers the second wafer to the first preset position. The carrier mechanism is placed below the second wafer, and the first wafer is held in the second preset position by the clamping mechanism and placed on top of the second wafer. Several magnetic sensing arrays under the first preset position correspond to several magnetic array marks on the second wafer, and no magnetic array mark is completely outside the coverage area of ​​the magnetic sensing array. E) The magnetic sensor array simultaneously acquires the magnetic field distribution information generated by the first wafer magnetic array marker and the second wafer magnetic array marker, obtains the relative position information of the second wafer, and then obtains the absolute position information of the second wafer; F) Based on the absolute position information of the first wafer and the second wafer, obtain the spatial vector error information of the first wafer and the second wafer; the clamping mechanism drives the first wafer to perform fine-tuning alignment; G) Set the fine-tuned position of the clamping mechanism to the third preset position; repeat step E until the spatial vector error between the first wafer and the second wafer is less than the preset tolerance limit; H) The first wafer, held by the clamping mechanism, approaches the second wafer in the vertical direction to complete the bonding process.

2. The wafer bonding magnetic array alignment method according to claim 1, characterized in that, When the absolute position information of the first wafer and the second wafer is obtained, the warpage of the wafer is acquired and it is checked whether it exceeds the preset tolerance limit.

3. The wafer bonding magnetic array alignment method according to claim 1, characterized in that, The first preset position and the second preset position are corrected by a calibration plate.

4. The wafer bonding magnetic array alignment method according to claim 1, characterized in that, At the preset position, each magnetic marker in the magnetic array is within the coverage area of ​​the corresponding magnetic sensing array.

5. The wafer bonding magnetic array alignment method according to claim 1, characterized in that, In step F, the first wafer and the second wafer are parallel, and the distance between the first wafer and the second wafer is less than the thickness of one wafer.

Images