Wafer-to-wafer bonding method and wafer-to-wafer bonding equipment
By aligning the reader alignment marks and bond marks during wafer-to-wafer bonding, calculating and performing movement information, the misalignment and alignment instability caused by multiple movement exchanges are solved, and the alignment accuracy and output are improved.
Patent Information
- Application Number
- CN202411919173.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-04-11
AI Technical Summary
During the wafer-to-wafer bonding process, there are multiple moving exchanges between the upper and lower workpiece tables, resulting in misalignment and unstable alignment, which affects the alignment accuracy and output.
By moving the workpiece table between the measured position and the bond position of the bond chamber, alignment marks and bond marks are performed using the upper and lower readers alignment marks and bond marks, the movement information is calculated and performed to achieve accurate workpiece table position adjustment and wafer bonding.
This method improves alignment accuracy, reduces misalignment problems caused by multiple movement exchanges, simplifies the alignment process, and thus improves yield.
Smart Images
Figure CN119812044A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to, but is not limited to, a wafer-to-wafer bonding method and a wafer-to-wafer bonding device. Background Art
[0002] Hybrid bonding processes can be divided into wafer to wafer (W2W) bonding, chip to wafer (C2W) bonding, and chip to chip (C2C) bonding according to the bonding object. In the related art, there are still many challenges in the process of wafer to wafer bonding. Summary of the invention
[0003] According to a first aspect of an embodiment of the present disclosure, a wafer-to-wafer bonding method is provided, the wafer-to-wafer bonding method comprising:
[0004] At a measurement position in the bonding chamber, the first alignment mark of the first lower workpiece stage and the first bonding mark of the first wafer fixed on the first lower workpiece stage are sequentially aligned by an upper reader to obtain a first position coordinate of the first bonding mark;
[0005] Aligning a second bonding mark of a second wafer fixed to an upper worktable at a bonding position of the bonding chamber by a lower reader to obtain second position coordinates of the second bonding mark;
[0006] Based on the first position coordinates and the second position coordinates, obtaining first movement information that the first lower workpiece stage needs to move from the measuring position to the bonding position;
[0007] Based on the first movement information, the first lower workpiece stage is moved from the measuring position to a corresponding position of the bonding position;
[0008] The first wafer is bonded to the second wafer.
[0009] In some embodiments, the wafer-to-wafer bonding method further comprises:
[0010] while moving the first lower work stage from the measuring position to a position corresponding to the bonding position based on the first movement information, moving the second lower work stage from the bonding position to the measuring position;
[0011] While the first wafer is bonded to the second wafer, the second alignment mark of the second lower worktable and the third bonding mark of the third wafer fixed on the second lower worktable are aligned in sequence at the measurement position by the upper reader to obtain the third position coordinates of the third bonding mark; while the first wafer is bonded to the second wafer, second movement information that the second lower worktable needs to move from the measurement position to the bonding position is obtained based on the second position coordinates and the third position coordinates.
[0012] In some embodiments, the wafer-to-wafer bonding method further comprises:
[0013] After bonding the first wafer to the second wafer, the first lower work stage is moved from the bonding position to the measuring position, and simultaneously based on the second movement information, the second lower work stage is moved from the measuring position to a corresponding position of the bonding position.
[0014] In some embodiments, the wafer-to-wafer bonding device includes a grating position system; the grating position system includes a planar grating and a grating reading head located on the first lower worktable and the second lower worktable, a magnetically levitated planar motor and a guide rail structure located in the bonding chamber; wherein,
[0015] The guide rail structure includes a first guide rail and a second guide rail respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail and a fourth guide rail respectively located on the top wall and the bottom wall of the bonding chamber; the first lower workpiece stage can be moved by the first guide rail and the third guide rail, and the second lower workpiece stage can be moved by the second guide rail and the fourth guide rail.
[0016] In some embodiments, the measuring position in the bonding chamber sequentially aligns the first alignment mark of the first lower workpiece stage and the first bonding mark of the first wafer fixed on the first lower workpiece stage by the upper reader to obtain the first position coordinates of the first bonding mark, including:
[0017] Aligning a first alignment mark of the first lower workpiece stage by the upper reader at the measuring position to obtain a first initial position coordinate of the first alignment mark;
[0018] The first bonding mark of the first wafer fixed on the first lower workpiece stage is aligned by the first coarse adjustment stage, the first fine adjustment stage and the upper reader of the first lower workpiece stage to obtain the first position coordinates.
[0019] In some embodiments, the wafer-to-wafer bonding method further comprises:
[0020] Before aligning the first bonding mark of the first wafer fixed on the first lower worktable by the upper reader at the measuring position, the first wafer is placed on the first lower worktable by a robot, and the second wafer is placed on the front of the upper worktable by the robot.
[0021] According to a second aspect of an embodiment of the present disclosure, there is provided a wafer-to-wafer bonding device, the wafer-to-wafer bonding device comprising a software system, and a first lower work stage, an upper work stage, an upper reader, a lower reader, and a grating position system located in a bonding chamber;
[0022] The upper reader is used to align the first alignment mark of the first lower workpiece stage and the first bonding mark of the first wafer fixed on the first lower workpiece stage in sequence at the measurement position of the bonding chamber to obtain the first position coordinates of the first bonding mark;
[0023] The lower reader is used to align the second bonding mark of the second wafer fixed to the upper workpiece stage at the bonding position of the bonding chamber to obtain the second position coordinates of the second bonding mark;
[0024] The software system is used to obtain first movement information that the first lower workpiece stage needs to move from the measuring position to the bonding position based on the first position coordinates and the second position coordinates;
[0025] The grating position system is used to move the first lower workpiece stage from the measuring position to a corresponding position of the bonding position based on the first movement information;
[0026] The first lower worktable and the upper worktable are used to bond the first wafer to the second wafer.
[0027] In some embodiments, the wafer-to-wafer bonding apparatus further includes a second lower workpiece stage;
[0028] The grating position system is used to move the second lower workpiece stage from the bonding position to the measuring position while the grating position system moves the first lower workpiece stage from the measuring position to a corresponding position of the bonding position based on the first movement information;
[0029] While the first wafer is bonded to the second wafer, the upper reader is used to align the second alignment mark of the second lower worktable and the third bonding mark of the third wafer fixed on the second lower worktable in sequence at the measuring position to obtain the third position coordinates of the third bonding mark; while the first wafer is bonded to the second wafer, the software system is used to obtain second movement information that the second lower worktable needs to move from the measuring position to the bonding position based on the second position coordinates and the third position coordinates.
[0030] In some embodiments, after bonding the first wafer to the second wafer, the grating position system is used to move the first lower worktable to the measurement position, and the grating position system is used to move the second lower worktable from the measurement position to a corresponding position of the bonding position based on the second movement information.
[0031] In some embodiments, the grating position system includes a planar grating and a grating reading head located on the first lower workpiece stage and the second lower workpiece stage, and a magnetically levitated planar motor and a guide rail structure located in the bonding chamber; wherein,
[0032] The guide rail structure includes a first guide rail and a second guide rail respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail and a fourth guide rail respectively located on the top wall and the bottom wall of the bonding chamber; the first guide rail and the third guide rail are used to control the movement of the first lower workpiece stage, and the second guide rail and the fourth guide rail are used to control the movement of the second lower workpiece stage.
[0033] In the disclosed embodiment, at the measuring position of the bonding chamber, the first alignment mark of the first lower worktable and the first bonding mark of the first wafer fixed on the first lower worktable are aligned in sequence by the upper reader to obtain the first position coordinates of the first bonding mark, and at the bonding position of the bonding chamber, the second bonding mark of the second wafer fixed on the upper worktable is aligned by the lower reader to obtain the second position coordinates of the second bonding mark, and then based on the first position coordinates and the second position coordinates, the first movement information that the first lower worktable needs to move from the measuring position to the bonding position is obtained. In this way, the upper and lower worktables do not need to be moved and exchanged multiple times, so that the problems of misalignment and unstable alignment caused by multiple movements and exchanges of the upper and lower worktables can be improved, so that the alignment accuracy is greatly improved, and the yield is improved due to the simplification of the alignment process. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figures 1 to 6 A schematic diagram of a wafer-to-wafer bonding process provided by an embodiment of the present disclosure.
[0035] Figure 7 A schematic diagram of a process of a wafer-to-wafer bonding method provided in accordance with an embodiment of the present disclosure.
[0036] Figures 8 to 9 A schematic diagram of a wafer-to-wafer bonding process provided by another embodiment of the present disclosure.
[0037] Fig.10 A schematic diagram of a wafer-to-wafer bonding device according to an embodiment of the present disclosure Figure 1 .
[0038] Fig.11 A schematic diagram of a wafer-to-wafer bonding device according to an embodiment of the present disclosure Figure 2 .
[0039] Fig.12 A schematic diagram of a wafer-to-wafer bonding device according to an embodiment of the present disclosure Figure 3 . DETAILED DESCRIPTION
[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the specific embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0041] In the following description, a large number of specific details are given to provide a more thorough understanding of the present disclosure. However, it is obvious to those skilled in the art that the present disclosure can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present disclosure, some technical features known in the art are not described; that is, all features of actual embodiments are not described here, and well-known functions and structures are not described in detail.
[0042] In the drawings, the sizes of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like reference numerals denote like elements throughout.
[0043] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present disclosure necessarily has the first element, component, region, layer or part.
[0044] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.
[0045] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present disclosure. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.
[0046] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present disclosure.
[0047] As the feature size of memory decreases and the interconnection density increases, memory is developing towards three-dimensional direction. Among them, hybrid bonding technology can realize the three-dimensional integration of two different functional chips (also known as tube cores). For example, hybrid bonding of memory array chips and peripheral circuit chips can realize three-dimensional memory with smaller size, higher interconnection density and lower power consumption.
[0048] Hybrid bonding processes can be divided into wafer-to-wafer bonding, chip-to-wafer bonding, and chip-to-chip bonding according to the bonding object. In the process of wafer-to-wafer bonding, advanced control systems and precise mechanical structures are usually required to achieve high-precision bonding operations. Mainstream hybrid bonding equipment, combined with high-precision alignment and monitoring systems, can achieve wafer-to-wafer bonding by adjusting equipment parameters and process conditions.
[0049] Figures 1 to 6 FIG. 1 shows a process diagram of wafer-to-wafer bonding. Figure 1 As shown, the bonding chamber of the wafer-to-wafer bonding equipment is divided into a loading position and a bonding position. The lower workpiece stage 101 is placed on the first wafer 102 at the loading position, and the lower workpiece stage 101 is moved from the loading position to the bonding position; Figure 2 As shown, the alignment mark 103 of the workpiece stage 101 is aligned with the reference mark reader 104 at the bonding position, the bonding mark of the first wafer 102 is aligned with the upper reader 105, and the second wafer 107 is placed on the workpiece stage 106 at the loading position; Figure 3 As shown, the lower workpiece stage 101 moves from the bonding position to the loading position, and the upper reader 105 and the lower reader 108 are calibrated at the bonding position; Figure 4 As shown, the upper work stage 106 moves from the loading position to the bonding position, and the bonding mark of the second wafer 107 fixed by the work stage 106 is aligned with the lower reader 108 at the bonding position; Figure 5 As shown, the lower workpiece stage 101 is moved from the loading position to the bonding position, and the alignment mark 103 of the lower workpiece stage 101 is aligned with the reference mark reader 104 at the bonding position; Figure 6 As shown, the first wafer 102 and the second wafer 107 are bonded at a bonding position.
[0050] The wafer-to-wafer bonding process provided in the above embodiment adopts coaxial upper and lower dual readers, and uses visible light to respectively identify and compensate for the positions of the upper and lower wafers. This method involves multiple movements and exchanges of the upper and lower worktables, and it is necessary to record the movement error of the worktable and the difference between the upper and lower readers. It has extremely high requirements on the stability of hardware movement and control, and is very prone to misalignment and unstable alignment problems, and there is a serious bottleneck in production.
[0051] The present disclosure provides a wafer-to-wafer bonding method. Figure 7 As shown, the following steps are included:
[0052] Step S1001: aligning a first alignment mark of a first lower workpiece stage and a first bonding mark of a first wafer fixed on the first lower workpiece stage in sequence by an upper reader at a measurement position in a bonding chamber to obtain first position coordinates of the first bonding mark;
[0053] Step S1002: aligning a second bonding mark of a second wafer fixed to an upper worktable at a bonding position in the bonding chamber by a lower reader to obtain second position coordinates of the second bonding mark;
[0054] Step S1003: based on the first position coordinates and the second position coordinates, obtaining first movement information that the first lower workpiece stage needs to move from the measuring position to the bonding position;
[0055] Step S1004: based on the first movement information, moving the first lower workpiece stage from the measuring position to a corresponding position of the bonding position;
[0056] Step S1005: bonding the first wafer to the second wafer.
[0057] Figures 8 to 9 Schematic diagram of the wafer-to-wafer bonding process provided by the embodiment of the present disclosure. Figure 8 As shown, at the measurement position of the bonding chamber 219, the first alignment mark 203 of the first lower work stage 202 and the first bonding mark of the first wafer 204 fixed on the first lower work stage 202 are aligned in sequence by the upper reader 201; at the bonding position of the bonding chamber 219, the second bonding mark of the second wafer 207 fixed on the upper work stage 206 is aligned by the lower reader 205. Fig. 9 As shown, the first lower workpiece stage 202 is moved from the measuring position to a corresponding position of the bonding position based on the first movement information, so as to bond the first wafer 204 to the second wafer 207 .
[0058] In the disclosed embodiment, at the measuring position of the bonding chamber 219, the first alignment mark 203 of the first lower worktable 202 and the first bonding mark of the first wafer 204 fixed on the first lower worktable 202 are aligned in sequence by the upper reader 201 to obtain the first position coordinates of the first bonding mark, and at the bonding position of the bonding chamber 219, the second bonding mark of the second wafer 207 fixed on the upper worktable 206 is aligned by the lower reader 205 to obtain the second position coordinates of the second bonding mark, and then based on the first position coordinates and the second position coordinates, the first movement information that the first lower worktable 202 needs to move from the measuring position to the bonding position is obtained, so that the upper and lower worktables do not need to be moved and exchanged multiple times, so that the problems of misalignment and unstable alignment caused by multiple movements and exchanges of the upper and lower worktables can be improved, so that the alignment accuracy is greatly improved, and the yield is improved due to the simplification of the alignment process.
[0059] In some specific examples, the first lower worktable 202, the upper worktable 206, and the second lower worktable 209 described later include a base, an adjustment table located on the base, and a chuck located on the adjustment table. The chuck can be used to adsorb the wafer to be bonded, and the adjustment table can be used to coarsely and finely adjust the position of the wafer to be bonded on the worktable.
[0060] In some specific examples, a first bonding mark (not shown) is disposed on one side of the bonding surface of the first wafer 204, such as Fig.10 As shown, a second bonding mark 208 is disposed on one side of the bonding surface of the second wafer 207 , and the surfaces of the first bonding mark and the second bonding mark 208 are both exposed and not blocked, so as to facilitate subsequent reader recognition.
[0061] The first wafer 204 , the second wafer 207 and the third wafer described below are all made of any semiconductor material suitable for a semiconductor structure, and may be various semiconductors such as silicon on insulator and silicon germanium on insulator.
[0062] The upper reader 201 includes an upper lens, and the lower reader 205 includes a lower lens. Both the upper lens and the lower lens may include an optical device for reading (identifying) the bonding mark on the wafer and detecting the position of the bonding mark. The upper reader 201 and the lower reader 205 each include a light source, a camera, and an optical lens on the camera. For example, the upper reader 201 and the lower reader 205 may each include one or more infrared charge-coupled device observation mirrors. In some embodiments, the upper reader 201 and the lower reader 205 may also include any suitable optical device for locating the bonding mark, such as a linear variable differential converter, a laser interferometer, or an optical linear encoder and decoder, etc. The camera may be monochrome or color, not limited to CDD or CMOS, not limited to resolution, and not limited to analog or digital. The front end of the camera may be equipped with a lens that determines the size of the field of view (there may be multiple switchable lenses).
[0063] In some embodiments, the wafer-to-wafer bonding method further comprises:
[0064] Before the first bonding mark of the first wafer 204 fixed on the first lower worktable 202 is aligned by the upper reader 201 at the measuring position, the first wafer 204 is placed on the first lower worktable 202 by the robot 220, and the second wafer 207 is placed on the front of the upper worktable 206 by the robot 220.
[0065] Here, the front side of the upper workpiece table 206 can be understood as the side of the workpiece table with the chuck.
[0066] In some embodiments, Fig. 9 as well as Fig.10 As shown, the wafer-to-wafer bonding method further includes:
[0067] While moving the first lower workpiece stage 202 from the measuring position to a position corresponding to the bonding position based on the first movement information, moving the second lower workpiece stage 209 from the bonding position to the measuring position;
[0068] While the first wafer 204 and the second wafer 207 are bonded, the second alignment mark 210 of the second lower worktable 209 and the third bonding mark of the third wafer 211 fixed on the second lower worktable 209 are aligned in sequence at the measuring position through the upper reader 201 to obtain the third position coordinates of the third bonding mark; while the first wafer 204 and the second wafer 207 are bonded, the second movement information that the second lower worktable 209 needs to move from the measuring position to the bonding position is obtained based on the second position coordinates and the third position coordinates.
[0069] In some specific examples, while the first wafer 204 is bonded to the second wafer 207, and before the third bonding mark of the third wafer 211 fixed on the second lower work stage 209 is aligned by the upper reader 201 at the measuring position, the third wafer 211 is placed on the second lower work stage 209 at the measuring position by the robot 220. After the first wafer 204 and the second wafer 207 are bonded at the bonding position, the next wafer to be bonded is placed on the front of the upper work stage 206 at the bonding position by the robot 220.
[0070] The lower worktable in the embodiment of the present disclosure adopts a double worktable setting, and the first lower worktable 202, the second lower worktable 209 and the upper worktable 206 are respectively arranged in the upper and lower layers in the bonding chamber 219, wherein the first lower worktable 202 and the second lower worktable 209 are located in the lower layer, and the upper worktable 206 is located in the upper layer. The embodiment of the present disclosure sets two lower worktables and makes the two lower worktables work alternately, and the first lower worktable 202 and the second lower worktable 209 can move back and forth between the measuring position and the bonding position. By setting the first lower worktable 202 and the second lower worktable 209 and making the two lower worktables work alternately, the working efficiency of the wafer-to-wafer bonding equipment is further improved, thereby further improving the output.
[0071] In some embodiments, the wafer-to-wafer bonding method further comprises:
[0072] After bonding the first wafer 204 and the second wafer 207 , the first lower worktable 202 is moved from the bonding position to the measuring position, and simultaneously based on the second movement information, the second lower worktable 209 is moved from the measuring position to a corresponding position of the bonding position.
[0073] In some specific examples, after moving the second lower worktable 209 from the measurement position to the corresponding position of the bonding position, the second lower worktable 209 is bonded to the next wafer to be bonded fixed to the upper worktable 206, and at the same time as the second lower worktable 209 is bonded to the next wafer to be bonded fixed to the upper worktable 206, the bonded wafer on the first lower worktable 202 moved to the measurement position is taken out by the robot 220, and at the same time as the second lower worktable 209 is bonded to the next wafer to be bonded fixed to the upper worktable 206, the first lower worktable 202 completes the alignment of the first alignment mark of the first lower worktable 202 with the upper reader, the loading of the next wafer to be bonded, and the alignment of the next wafer to be bonded with the upper reader.
[0074] In the disclosed embodiment, at the measuring position, the alignment mark of the lower work stage and the upper reader are aligned, the bottom wafer (first wafer 204, third wafer 211) is placed, and the bonding mark of the bottom wafer is aligned with the upper reader 201. After bonding is completed, the bonded wafer is placed at the measuring position. At the bonding position, the upper work stage 206 is fixed, the top wafer (second wafer 207) is placed, and the bonding mark of the top wafer is aligned with the lower reader 205, as well as the nano-stage position compensation and bonding of the upper work stage 206 are completed.
[0075] In some embodiments, the wafer-to-wafer bonding equipment includes a raster position system; Fig.11 as well as Fig.12As shown, the grating position system includes a plane grating 212 and a grating reading head 213 located on the first lower workpiece stage 202 and the second lower workpiece stage 209, a magnetic levitation planar motor 214 and a guide rail structure located in the bonding chamber 219; wherein,
[0076] The guide rail structure includes a first guide rail 215 and a second guide rail 216 respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber 219, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail 217 and a fourth guide rail 218 respectively located on the top wall and the bottom wall of the bonding chamber 219; the first lower workpiece stage 202 can be moved by the first guide rail 215 and the third guide rail 217, and the second lower workpiece stage 209 can be moved by the second guide rail 216 and the fourth guide rail 218.
[0077] In the disclosed embodiment, the horizontal and vertical movement of the first lower workpiece stage 202 is controlled by the first guide rail 215 and the third guide rail 217; the horizontal and vertical movement of the second lower workpiece stage 209 is controlled by the second guide rail 216 and the fourth guide rail 218. A structure of a magnetic levitation planar motor + guide rail + planar grating + grating reading head is adopted. During the bonding alignment process, the upper workpiece stage 206 includes a coarse motion stage & a fine motion stage for precise alignment compensation, so as to accurately align the wafer to be bonded fixed by the upper workpiece stage 206 and the wafer to be bonded fixed by the lower workpiece stage. After that, the upper workpiece stage 206 is pressed down and bonds with the wafer to be bonded on a lower workpiece stage at the bonding position. After the bonding is completed, the lower workpiece stage moves from the bonding position to the measuring position. The other lower workpiece stage moves from the measuring position to the bonding position, and the alignment and bonding are performed cyclically in this way.
[0078] The workpiece stage uses plane grating measurement technology to precisely measure the position. Plane gratings 212 and grating reading heads 213 (grating interferometers) are arranged on the two lower workpiece stages. When the lower workpiece stage moves relative to the plane grating 212, the grating reading head 213 can measure the movement displacement of the lower workpiece stage. Grating ruler principle-the photoelectric detector and light source are integrated in the grating reading head 213. Light is irradiated onto the grating ruler's engraved surface to form special optical fringes. The receiver converts the optical signal into an electrical signal, which is then converted into a digital signal through a converter.
[0079] In some embodiments, the measurement position in the bonding chamber 219 is used by the upper reader 201 to sequentially align the first alignment mark 203 of the first lower workpiece stage 202 and the first bonding mark of the first wafer 204 fixed on the first lower workpiece stage 202 to obtain the first position coordinates of the first bonding mark, including:
[0080] At the measuring position, align the first alignment mark 203 of the first lower workpiece stage 202 by the upper reader 201 to obtain the first initial position coordinates of the first alignment mark 203;
[0081] The first bonding mark of the first wafer 204 fixed on the first lower workpiece stage 202 is aligned by the first coarse adjustment stage, the first fine adjustment stage and the upper reader 201 of the first lower workpiece stage 202 to obtain the first position coordinates.
[0082] In the disclosed embodiment, the first alignment mark 203 of the first lower workpiece stage 202 is aligned by the upper reader 201 at the measuring position to obtain the first initial position coordinates of the first alignment mark 203; the position of the first wafer 204 fixed on the first lower workpiece stage 202 is adjusted by the first coarse adjustment stage and the first fine adjustment stage of the first lower workpiece stage 202, so that the upper reader 201 is aligned with the first bonding mark of the first wafer 204 fixed on the first lower workpiece stage 202, and the relative position of the first alignment mark 203 of the first lower workpiece stage 202 and the first bonding mark of the first wafer 204 is obtained by the adjustment amplitude of the first coarse adjustment stage and the first fine adjustment stage, and then the first position coordinates are obtained based on the first initial position coordinates and the relative position of the first alignment mark 203 and the first bonding mark.
[0083] The wafer-to-wafer bonding equipment in the embodiment of the present disclosure includes a control unit, which is used to control the wafer-to-wafer bonding equipment to perform the above-mentioned wafer-to-wafer bonding method.
[0084] In the embodiment of the present disclosure, the bonding steps include: a first step, the upper worktable 206 above the bonding position is moved to the starting position, and the first lower worktable 202 is calibrated at the measuring position by the first alignment mark 203 and the upper reader 201, so that the first lower worktable 202 is at a predetermined position; a second step, the robot 220 places the first wafer 204 on the first lower worktable 202; the robot 220 places the second wafer 207 on the upper worktable 206; a third step, the first bonding mark of the first wafer 204 on the first lower worktable 202 is aligned with the coarse adjustment stage and the fine adjustment stage of the first lower worktable 202 and the upper reader 201, so as to obtain the relative alignment of the first lower worktable 202 and the first wafer 204. Align the second wafer 207 on the upper worktable 206 through the coarse adjustment table and fine adjustment table of the upper worktable 206 and the upper reader 201 to obtain the position coordinates of the second wafer 207; the third step, the position that needs to be moved from the measurement position to the bonding position on the first lower worktable 202 is calculated through the software system; the fourth step, the first lower worktable 202 moves from the measurement position to the corresponding position of the bonding position through the grating position system; the fifth step, the second wafer 207 is bonded to the first wafer 204 at the bonding position, and after the bonding is completed, the first lower worktable 202 moves to the measurement position, and the robot 220 takes away the bonded wafer; next, the first lower worktable 202 is exchanged with the second lower worktable 209, and the operation is cyclical according to the process.
[0085] In the disclosed embodiment, the dual worktable technology of the first lower worktable 202 and the second lower worktable 209 separates the upper and lower wafer, positioning, and alignment bonding processes of the bottom wafer into two parallel processing parts. One lower worktable performs the upper and lower wafer, positioning, and other preparatory work of the bottom wafer at the measuring position, while the other lower worktable performs alignment bonding of the bottom wafer and the top wafer at the bonding position. After the bonding is completed, the two lower worktables exchange positions, and the wafers are cyclically efficiently aligned and bonded. In order to achieve high acceleration, high speed, and high precision movement within a large stroke range, the worktable generally adopts a coarse-fine laminated structure. Among them, the coarse motion stage completes large stroke and micron-level precision movement; the small stroke micro (fine) motion stage is superimposed on the coarse motion stage to compensate for the motion error of the coarse motion stage, and finally achieve nanometer-level motion accuracy.
[0086] Based on the above wafer-to-wafer bonding method, the embodiment of the present disclosure also provides a wafer-to-wafer bonding device, such as Figures 10 to 12 As shown, the wafer-to-wafer bonding equipment includes a software system, and a first lower work stage 202, an upper work stage 206, an upper reader 201, a lower reader 205, and a grating position system located in a bonding chamber 219;
[0087] The upper reader 201 is used to sequentially align the first alignment mark 203 of the first lower workpiece stage 202 and the first bonding mark of the first wafer 204 fixed on the first lower workpiece stage 202 at the measuring position of the bonding chamber 219 to obtain the first position coordinates of the first bonding mark;
[0088] The lower reader 205 is used to align the second bonding mark 208 of the second wafer 207 fixed to the upper workpiece stage 206 at the bonding position of the bonding chamber 219 to obtain the second position coordinates of the second bonding mark 208;
[0089] The software system is used to obtain first movement information that the first lower workpiece stage 202 needs to move from the measuring position to the bonding position based on the first position coordinates and the second position coordinates;
[0090] The grating position system is used to move the first lower workpiece stage 202 from the measuring position to a corresponding position of the bonding position based on the first movement information;
[0091] The first lower work stage 202 and the upper work stage 206 are used to bond the first wafer 204 and the second wafer 207 .
[0092] In some embodiments, Figures 10 to 12 As shown, the wafer-to-wafer bonding equipment further includes a second lower workpiece stage 209;
[0093] While the grating position system moves the first lower workpiece stage 202 from the measuring position to a position corresponding to the bonding position based on the first movement information, the grating position system is used to move the second lower workpiece stage 209 from the bonding position to the measuring position;
[0094] While the first wafer 204 and the second wafer 207 are bonded, the upper reader 201 is used to align the second alignment mark 210 of the second lower worktable 209 and the third bonding mark of the third wafer 211 fixed on the second lower worktable 209 in sequence at the measuring position to obtain the third position coordinates of the third bonding mark; while the first wafer 204 and the second wafer 207 are bonded, the software system is used to obtain the second movement information that the second lower worktable 209 needs to move from the measuring position to the bonding position based on the second position coordinates and the third position coordinates.
[0095] In some embodiments, after bonding the first wafer 204 to the second wafer 207, the grating position system is used to move the first lower workpiece stage 202 to the measurement position, and the grating position system is used to move the second lower workpiece stage 209 from the measurement position to a corresponding position of the bonding position based on the second movement information.
[0096] In some embodiments, Fig.11 as well as Fig.12 As shown, the grating position system includes a plane grating 212 and a grating reading head 213 located on the first lower workpiece stage 202 and the second lower workpiece stage 209, a magnetic levitation planar motor 214 and a guide rail structure located in the bonding chamber 219; wherein,
[0097] The guide rail structure includes a first guide rail 215 and a second guide rail 216 respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber 219, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail 217 and a fourth guide rail 218 respectively located on the top wall and the bottom wall of the bonding chamber 219; the first guide rail 215 and the third guide rail 217 are used to control the movement of the first lower workpiece stage 202, and the second guide rail 216 and the fourth guide rail 218 are used to control the movement of the second lower workpiece stage 209.
[0098] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present disclosure. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in the various embodiments of the present disclosure, the size of the serial number of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present disclosure. The serial numbers of the embodiments of the present disclosure are for description only and do not represent the advantages and disadvantages of the embodiments.
[0099] The methods disclosed in several method embodiments provided in the present disclosure can be arbitrarily combined without conflict to obtain new method embodiments.
[0100] The above description is only a specific implementation mode of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure.
Claims
1. A wafer-to-wafer bonding method, characterized in that: The wafer-to-wafer bonding method comprises: At a measurement position in the bonding chamber, the first alignment mark of the first lower workpiece stage and the first bonding mark of the first wafer fixed on the first lower workpiece stage are sequentially aligned by an upper reader to obtain a first position coordinate of the first bonding mark; Aligning a second bonding mark of a second wafer fixed to an upper worktable at a bonding position of the bonding chamber by a lower reader to obtain second position coordinates of the second bonding mark; Based on the first position coordinates and the second position coordinates, obtaining first movement information that the first lower workpiece stage needs to move from the measuring position to the bonding position; Based on the first movement information, the first lower workpiece stage is moved from the measuring position to a corresponding position of the bonding position; The first wafer is bonded to the second wafer.
2. The wafer-to-wafer bonding method according to claim 1, characterized in that: The wafer-to-wafer bonding method further comprises: while moving the first lower work stage from the measuring position to a position corresponding to the bonding position based on the first movement information, moving the second lower work stage from the bonding position to the measuring position; While the first wafer is bonded to the second wafer, the second alignment mark of the second lower worktable and the third bonding mark of the third wafer fixed on the second lower worktable are aligned in sequence at the measurement position by the upper reader to obtain the third position coordinates of the third bonding mark; while the first wafer is bonded to the second wafer, second movement information that the second lower worktable needs to move from the measurement position to the bonding position is obtained based on the second position coordinates and the third position coordinates.
3. The wafer-to-wafer bonding method according to claim 2, characterized in that: The wafer-to-wafer bonding method further comprises: After bonding the first wafer to the second wafer, the first lower work stage is moved from the bonding position to the measuring position, and simultaneously based on the second movement information, the second lower work stage is moved from the measuring position to a corresponding position of the bonding position.
4. The wafer-to-wafer bonding method according to claim 2, characterized in that: The wafer-to-wafer bonding device includes a grating position system; the grating position system includes a plane grating and a grating reading head located on the first lower worktable and the second lower worktable, a magnetically levitated planar motor and a guide rail structure located in the bonding chamber; wherein, The guide rail structure includes a first guide rail and a second guide rail respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail and a fourth guide rail respectively located on the top wall and the bottom wall of the bonding chamber; the first lower workpiece stage can be moved by the first guide rail and the third guide rail, and the second lower workpiece stage can be moved by the second guide rail and the fourth guide rail.
5. The wafer-to-wafer bonding method according to claim 1, characterized in that: The method of sequentially aligning a first alignment mark of a first lower workpiece stage and a first bonding mark of a first wafer fixed on the first lower workpiece stage at a measurement position in the bonding chamber by an upper reader to obtain a first position coordinate of the first bonding mark includes: Aligning a first alignment mark of the first lower workpiece stage by the upper reader at the measuring position to obtain a first initial position coordinate of the first alignment mark; The first bonding mark of the first wafer fixed on the first lower workpiece stage is aligned by the first coarse adjustment stage, the first fine adjustment stage and the upper reader of the first lower workpiece stage to obtain the first position coordinates.
6. The wafer-to-wafer bonding method according to claim 1, characterized in that: The wafer-to-wafer bonding method further comprises: Before aligning the first bonding mark of the first wafer fixed on the first lower worktable by the upper reader at the measuring position, the first wafer is placed on the first lower worktable by a robot, and the second wafer is placed on the front of the upper worktable by the robot.
7. A wafer-to-wafer bonding device, characterized in that: The wafer-to-wafer bonding equipment includes a software system, and a first lower work stage, an upper work stage, an upper reader, a lower reader, and a grating position system located in a bonding chamber; The upper reader is used to align the first alignment mark of the first lower workpiece stage and the first bonding mark of the first wafer fixed on the first lower workpiece stage in sequence at the measurement position of the bonding chamber to obtain the first position coordinates of the first bonding mark; The lower reader is used to align the second bonding mark of the second wafer fixed to the upper workpiece stage at the bonding position of the bonding chamber to obtain the second position coordinates of the second bonding mark; The software system is used to obtain first movement information that the first lower workpiece stage needs to move from the measuring position to the bonding position based on the first position coordinates and the second position coordinates; The grating position system is used to move the first lower workpiece stage from the measuring position to a corresponding position of the bonding position based on the first movement information; The first lower worktable and the upper worktable are used to bond the first wafer to the second wafer.
8. The wafer-to-wafer bonding device according to claim 7, characterized in that: The wafer-to-wafer bonding apparatus further includes a second lower workpiece stage; The grating position system is used to move the second lower workpiece stage from the bonding position to the measuring position while the grating position system moves the first lower workpiece stage from the measuring position to a corresponding position of the bonding position based on the first movement information; While the first wafer is bonded to the second wafer, the upper reader is used to align the second alignment mark of the second lower worktable and the third bonding mark of the third wafer fixed on the second lower worktable in sequence at the measuring position to obtain the third position coordinates of the third bonding mark; while the first wafer is bonded to the second wafer, the software system is used to obtain second movement information that the second lower worktable needs to move from the measuring position to the bonding position based on the second position coordinates and the third position coordinates.
9. The wafer-to-wafer bonding apparatus according to claim 8, characterized in that: After bonding the first wafer to the second wafer, the grating position system is used to move the first lower workpiece stage to the measurement position, and the grating position system is used to move the second lower workpiece stage from the measurement position to a corresponding position of the bonding position based on the second movement information.
10. The wafer-to-wafer bonding device according to claim 8, characterized in that: The grating position system includes a plane grating and a grating reading head located on the first lower workpiece stage and the second lower workpiece stage, and a magnetic levitation planar motor and a guide rail structure located in the bonding chamber; wherein, The guide rail structure includes a first guide rail and a second guide rail respectively located on two side walls opposite to each other along a first direction among multiple side walls of the bonding chamber, and the first direction is the arrangement direction of the measuring position and the bonding position; the guide rail structure also includes a third guide rail and a fourth guide rail respectively located on the top wall and the bottom wall of the bonding chamber; the first guide rail and the third guide rail are used to control the movement of the first lower workpiece stage, and the second guide rail and the fourth guide rail are used to control the movement of the second lower workpiece stage.