Wafer bonding alignment apparatus, method and wafer bonder

Abstract

The application discloses a wafer bonding alignment device, method and wafer bonding machine. The device comprises a first pressure head and a second pressure head arranged oppositely, a first camera located outside a first wafer covering area of the first pressure head, a second camera located inside a second wafer covering area of the second pressure head, and a controller. The first pressure head further comprises a first pressure head mark located inside the first wafer covering area. The second pressure head further comprises a second pressure head mark located outside the second wafer covering area. The controller is used to control the second pressure head to move to align the second pressure head with the first pressure head, to control the second pressure head to move until the first wafer is aligned with the second pressure head to obtain first position information of the second pressure head, to control the second pressure head to move until the second wafer is aligned with the first pressure head to obtain second position information of the second pressure head, and to control the second pressure head to move according to the first position information and the second position information to align the first wafer with the second wafer. The application is beneficial to improving the alignment precision.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a wafer bonding alignment apparatus, method, and wafer bonding machine. Background Technology

[0002] With the development of the integrated circuit industry, wafer bonding technology can achieve higher-layer stacking of devices, thus attracting increasing attention. However, due to the relatively short history of wafer bonding equipment, it still has many shortcomings compared to other semiconductor equipment. Therefore, the development of wafer bonding equipment will have an increasingly significant impact on the future semiconductor industry.

[0003] Current wafer bonding technology does not have high alignment requirements for wafer bonding equipment used to fabricate substrates. Alignment accuracy of 100 micrometers is sufficient, which can usually be achieved by using the external dimensional features of the wafer in conjunction with a low-magnification camera.

[0004] However, the alignment requirements for bonding equipment on patterned wafers (which are opaque and cannot be aligned using infrared beam alignment technology) are extremely high, typically reaching the submicron level (10nm~100nm). Bonding alignment equipment that meets this precision usually uses marker alignment in conjunction with a high-magnification camera to achieve submicron alignment.

[0005] In practical applications, wafer marker alignment typically requires localized polishing of the back side of the wafer at the marked location to ensure sufficient light transmittance of the wafer marker, thereby achieving alignment between the two wafer markers. However, the number of pattern layers on the wafer cannot be too high, otherwise it will affect the light transmittance of the marker. This limitation has significantly hindered the application of bonding technology in higher-layer stacks.

[0006] In existing technologies, solutions for achieving high-precision alignment of opaque wafers typically involve using an ultra-high-precision motion platform. After the wafer is placed on the platform, the platform and wafer move multiple times, and the positions of the upper and lower wafer markers are recorded by a camera. An algorithm is then used to theoretically align the upper and lower wafers.

[0007] This alignment method requires the platform to move multiple times. Therefore, the alignment accuracy depends on the motion accuracy of the alignment platform and the alignment algorithm. The low alignment accuracy can result from the low accuracy of the alignment platform and the complexity of the alignment algorithm. Summary of the Invention

[0008] This invention provides a wafer bonding alignment apparatus, method, and wafer bonding machine to solve the problem that existing patterned wafer alignment suffers from low alignment accuracy due to the low motion precision of the alignment platform and the complexity of the alignment algorithm.

[0009] In a first aspect, embodiments of the present invention provide a wafer bonding alignment apparatus, including a first pressure head, a second pressure head, at least one first camera, at least one second camera, and a controller; the first pressure head and the second pressure head are disposed opposite to each other along a first direction;

[0010] The surface of the first pressure head near the second pressure head includes a first wafer coverage area for carrying the first wafer and at least one first pressure head mark; the first camera is located outside the first wafer coverage area, and the first pressure head mark is located within the first wafer coverage area;

[0011] The second pressure head has a surface near the first pressure head that includes a second wafer coverage area for carrying the second wafer and at least one second pressure head mark; the second camera is located within the second wafer coverage area, and the second pressure head mark is located outside the second wafer coverage area;

[0012] The controller is communicatively connected to the second pressure head and is used to control the movement of the second pressure head so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera;

[0013] The controller is further configured to, after the first wafer is fixed in the area covered by the first wafer, control the second pressure head to move until the center of the first wafer is aligned with the second position along the first direction, and obtain the first position information of the second pressure head after the movement;

[0014] The controller is further configured to, after the second wafer is fixed in the area covered by the second wafer, control the second pressure head to move until the center of the second wafer is aligned with the first position along the first direction, and obtain the second position information of the second pressure head after the movement;

[0015] The controller is further configured to control the movement of the second pressure head according to the first position information and the second position information so that the center of the first wafer and the center of the second wafer are aligned along the first direction.

[0016] Optionally, the first position is the center of the first pressure head; the second position is the center of the second pressure head;

[0017] The controller is used to control the second pressure head to move to the initial zero position so that the center of the second pressure head is aligned with the center of the first pressure head along the first direction;

[0018] The controller is used to control the second pressure head to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction;

[0019] The controller is used to control the second pressure head to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction.

[0020] Optionally, the first wafer includes at least one first wafer marker; the first wafer marker has a first relative position relative to the shape of the first wafer, and the first pressure head marker has a second relative position relative to the area covered by the first wafer; the first relative position and the second relative position are the same;

[0021] The second wafer includes at least one second wafer mark; the second wafer mark has a third relative position relative to the shape of the second wafer, and the second pressure head mark has a fourth relative position relative to the area covered by the second wafer; the third relative position is the same as the fourth relative position.

[0022] Optionally, at least one first camera includes two first cameras; at least one first pressure head mark includes two first pressure head marks; at least one first wafer mark includes two first wafer marks;

[0023] At least one second camera includes two second cameras; at least one second pressure head mark includes two second pressure head marks; at least one second wafer mark includes two second wafer marks;

[0024] The first camera corresponds to the second pressure head mark; the second camera corresponds to the first pressure head mark.

[0025] Optionally, the first pressure head includes an electrostatic chuck;

[0026] The second pressure head includes a multi-degree-of-freedom motion platform.

[0027] In a second aspect, embodiments of the present invention provide a wafer bonding alignment method applied to the wafer bonding alignment apparatus described in the first aspect, the wafer bonding alignment method comprising:

[0028] The second pressure head is controlled to move so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera;

[0029] After the first wafer is fixed in the area covered by the first wafer, the second pressure head is controlled to move until the center of the first wafer is aligned with the second position along the first direction, and the first position information of the second pressure head after the movement is obtained;

[0030] After the second wafer is fixed in the area covered by the second wafer, the second pressure head is controlled to move until the center of the second wafer is aligned with the first position along the first direction, and the second position information of the second pressure head after the movement is obtained;

[0031] The second pressure head is controlled to move according to the first position information and the second position information so that the center of the first wafer and the center of the second wafer are aligned along the first direction.

[0032] Optionally, the first position is the center of the first pressure head; the second position is the center of the second pressure head;

[0033] Controlling the movement of the second pressure head to align the second position with the first position along the first direction includes:

[0034] Control the second pressure head to move to the initial zero position so that the center of the second pressure head is aligned with the center of the first pressure head along the first direction;

[0035] Controlling the movement of the second pressure head until the center of the first wafer and the center of the second pressure head are aligned along the first direction includes:

[0036] The second pressure head is controlled to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction;

[0037] Controlling the movement of the second pressure head until the center of the second wafer is aligned with the center of the first pressure head along the first direction includes:

[0038] The second pressure head is controlled to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction.

[0039] Optionally, the first wafer includes at least one first wafer marker; the first wafer marker has a first relative position relative to the shape of the first wafer, and the first pressure head marker has a second relative position relative to the area covered by the first wafer; the first relative position and the second relative position are the same;

[0040] The second wafer includes at least one second wafer mark; the second wafer mark has a third relative position relative to the shape of the second wafer, and the second pressure head mark has a fourth relative position relative to the area covered by the second wafer; the third relative position and the fourth relative position are the same;

[0041] Controlling the second pressure head to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction includes:

[0042] The second pressure head is controlled to move from the initial zero position until the center of the first wafer mark is located at the center of the field of view of the second camera;

[0043] Controlling the second pressure head to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction includes:

[0044] The second pressure head is controlled to move a preset distance from the initial zero position along the second direction, wherein the second direction is the direction in which the projection of the second wafer mark along the first direction points to the projection of the second pressure head mark along the first direction when the second pressure head is not moved;

[0045] Control the movement of the second pressure head until the center of the second wafer mark is located at the center of the field of view of the first camera;

[0046] Control the second pressure head to move the preset distance in a direction opposite to the second direction.

[0047] Optionally, after controlling the movement of the second pressure head according to the first position information and the second position information to align the center of the first wafer with the center of the second wafer along the first direction, the wafer bonding alignment method further includes:

[0048] A virtual marker is determined based on the first location information and the second location information, wherein the center of the virtual marker is located at the center of the field of view of the first camera;

[0049] During the process of controlling the first pressure head to move in the direction from the first pressure head toward the second pressure head, the movement of the first pressure head is adjusted according to the position of the center of the virtual mark in the field of view of the first camera.

[0050] Thirdly, embodiments of the present invention provide a wafer bonding machine, characterized in that it includes a wafer bonding alignment device as described in the first aspect.

[0051] The technical solution of this invention, by setting a first camera outside the first wafer coverage area, a first pressure head mark inside the first wafer coverage area, a second camera inside the second wafer coverage area, and a second pressure head mark outside the second wafer coverage area, and ensuring that when the center of the second pressure head is aligned with the center of the first pressure head along a first direction, the center of the first pressure head mark is located at the center of the field of view of the second camera and the center of the second pressure head mark is located at the center of the field of view of the first camera, after the first wafer is fixed in the first wafer coverage area, the first position information of the second pressure head when the center of the first wafer and the center of the second pressure head are aligned along the first direction can be determined by controlling the movement of the second pressure head and obtaining the field of view of the second camera during the movement of the second pressure head. Similarly, after the second wafer is fixed in the second wafer coverage area, the center of the second wafer and the center of the first pressure head can be determined by controlling the movement of the second pressure head and obtaining the field of view of the first camera during the movement of the second pressure head. The second position information of the second pressure head during alignment along the first direction is obtained. Finally, based on the obtained first and second position information, the movement of the second pressure head can be controlled to align the center of the first wafer with the center of the second wafer along the first direction. It is not necessary to use a second pressure head with high motion precision. After the first and second pressure heads are aligned, the deviation between the center of the first wafer and the center of the second wafer can be calculated by controlling the second pressure head to move twice, based on the obtained first and second position information. Then, the movement of the second pressure head is controlled to align the center of the first wafer with the center of the second wafer, reducing the number of alignment steps and the number of movements of the second pressure head. Moreover, the alignment of the wafer and the corresponding pressure head is determined by the field of view of the camera. The alignment algorithm is not complicated, which is conducive to improving alignment accuracy. The alignment accuracy mainly depends on the accuracy of the first and second cameras. The first and second cameras use commonly used high-magnification cameras, which can achieve sub-micron alignment accuracy.

[0052] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0053] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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 creative effort.

[0054] Figure 1 This is a schematic diagram of the structure of a wafer bonding alignment device provided in an embodiment of the present invention;

[0055] Figure 2This is a schematic diagram of the structure of a first pressure head and a first camera provided in an embodiment of the present invention;

[0056] Figure 3 This is a schematic diagram of the structure of a second pressure head and a second camera provided in an embodiment of the present invention;

[0057] Figure 4 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing that the center of the first pressure head and the center of the second pressure head are aligned along a first direction;

[0058] Figure 5 A schematic diagram of another structure provided in an embodiment of the present invention, in which the center of the first pressure head and the center of the second pressure head are aligned along a first direction;

[0059] Figure 6 A flowchart of a wafer bonding alignment method provided in an embodiment of the present invention;

[0060] Figure 7 A flowchart of another wafer bonding alignment method provided in an embodiment of the present invention;

[0061] Figure 8 A schematic diagram of the field of view of a first camera when the center of a first pressure head and the center of a second pressure head are aligned along a first direction, as provided in an embodiment of the present invention;

[0062] Figure 9 This is a schematic diagram illustrating the positional relationship between a first wafer and a second pressure head after the first wafer is fixed in the first wafer coverage area, as provided in an embodiment of the present invention.

[0063] Figure 10 This is a schematic diagram illustrating the positional relationship between the first wafer and the second pressure head when the center of the first wafer and the center of the second pressure head are aligned along a first direction, as provided in an embodiment of the present invention.

[0064] Figure 11 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing the alignment of the center of a first wafer with the center of a second pressure head along a first direction;

[0065] Figure 12 A schematic diagram of the field of view of a first camera when the center of a first wafer and the center of a second pressure head are aligned along a first direction, as provided in an embodiment of the present invention;

[0066] Figure 13 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing how a second pressure head moves a preset distance along a second direction from an initial zero position.

[0067] Figure 14 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing the alignment of the center of a second wafer with the center of a first pressure head along a first direction;

[0068] Figure 15 A schematic diagram of the field of view of a first camera when the center of a second wafer is aligned with the center of a first pressure head along a first direction, as provided in an embodiment of the present invention;

[0069] Figure 16 A flowchart illustrating yet another wafer bonding alignment method provided in an embodiment of the present invention;

[0070] Figure 17 This is a schematic diagram of the field of view of a first camera when a first pressure head moves in the direction of the first pressure head toward the second pressure head, as provided in an embodiment of the present invention.

[0071] Explanation of reference numerals in the attached figures: 10, first pressure head; 20, second pressure head; 30, first camera; 40, second camera; 50, controller; Y, first direction; 101, first wafer; 11, first wafer coverage area; 12, first pressure head mark; 201, second wafer; 21, second wafer coverage area; 22, second pressure head mark; 1011, first wafer mark; 301, center mark of the field of view of the first camera; X, second direction; 2011, second wafer mark; 22', virtual mark. Detailed Implementation

[0072] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0073] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices. The terms "upper," "lower," "left," "right," etc., indicate orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings and are only used to describe the relative positional relationships between components or constituent parts, and do not specifically limit the specific installation orientation of each component or constituent part.

[0074] Figure 1 This is a schematic diagram of a wafer bonding alignment device provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of a first pressure head and a first camera provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a second pressure head and a second camera provided in an embodiment of the present invention, with reference to... Figure 1 , Figure 2 and Figure 3 This invention provides a wafer bonding alignment apparatus, including a first pressure head 10, a second pressure head 20, at least one first camera 30, at least one second camera 40, and a controller 50. The first pressure head 10 and the second pressure head 20 are disposed opposite each other along a first direction Y. The surface of the first pressure head 10 near the second pressure head 20 includes a first wafer coverage area 11 for carrying a first wafer 101 and at least one first pressure head mark 12. The first camera 30 is located outside the first wafer coverage area 11, and the first pressure head mark 12 is located inside the first wafer coverage area 11. The surface of the second pressure head 20 near the first pressure head 10 includes a second wafer coverage area 21 for carrying a second wafer 201 and at least one second pressure head mark 22. The second camera 40 is located inside the second wafer coverage area 21, and the second pressure head mark 22 is located outside the second wafer coverage area 21.

[0075] The controller 50 is communicatively connected to the second pressure head 20 and is used to control the movement of the second pressure head 20 so that the second position of the second pressure head 20 is aligned with the first position of the first pressure head 10 along the first direction Y. The center of the first pressure head mark 12 is located at the center of the field of view of the second camera 40, and the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30. The controller 50 is also used to, after the first wafer 101 is fixed in the first wafer coverage area 11, control the movement of the second pressure head 20 until the center of the first wafer 101 is aligned with the second position along the first direction Y, and acquire the first position information of the moved second pressure head 20. The controller 50 is also used to, after the second wafer 201 is fixed in the second wafer coverage area 21, control the movement of the second pressure head 20 until the center of the second wafer 201 is aligned with the first position along the first direction Y, and acquire the second position information of the moved second pressure head 20. The controller 50 is also used to control the movement of the second pressure head 20 according to the first position information and the second position information so that the center of the first wafer 101 is aligned with the center of the second wafer 201 along the first direction Y.

[0076] In one feasible embodiment, the first wafer 101 includes at least one first wafer mark. The first wafer mark has a first relative position relative to the shape of the first wafer 101, and the first pressure head mark 12 has a second relative position relative to the first wafer coverage area 11. The first relative position is the same as the second relative position. The second wafer 102 includes at least one second wafer mark. The second wafer mark has a third relative position relative to the shape of the second wafer 102, and the second pressure head mark 22 has a fourth relative position relative to the second wafer coverage area 21. The third relative position is the same as the fourth relative position.

[0077] It should be noted that the controller 50 in this embodiment of the invention is also communicatively connected to the first camera 30 and the second camera 40, respectively, and can obtain the field of view of the first camera 30 and the field of view of the second camera 40. Then, based on the position of the second pressure head mark 22 in the field of view of the first camera 30 and the position of the first pressure head mark 12 in the field of view of the second camera 40, it can determine whether the second position of the second pressure head 20 and the first position of the first pressure head 10 are aligned along the first direction Y.

[0078] Figure 4 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing that the center of the first pressure head and the center of the second pressure head are aligned along a first direction. Figure 5 This is a schematic diagram of another structure provided by an embodiment of the present invention, in which the center of the first pressure head and the center of the second pressure head are aligned along a first direction. Figure 4 and Figure 5 The illustrated embodiment uses the first position of the first pressure head 10 as its center and the second position of the second pressure head 20 as its center. However, in other embodiments, the first position of the first pressure head 10 can be any position other than its center, and the second position of the second pressure head 20 can also be any position other than its center. This embodiment of the invention does not limit this. (See reference...) Figure 4 and Figure 5 When the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30 and the center of the first pressure head mark 12 is located at the center of the field of view of the second camera 40, the center of the second pressure head 20 and the center of the first pressure head 10 are aligned along the first direction Y. It should be noted that when the center of the second pressure head 20 and the center of the first pressure head 10 are aligned along the first direction Y, the center of the first wafer coverage area 11 and the center of the second pressure head 20 are also aligned along the first direction Y, and the center of the second wafer coverage area 21 and the center of the first pressure head 10 are also aligned along the first direction Y.

[0079] It should be noted that the first relative position of the first wafer mark on the first wafer 101 relative to the shape of the first wafer 101 and the second relative position of the first pressure head mark 12 relative to the first wafer coverage area 11 are the same, meaning that, in the same coordinate system, the orientation of the center of the first wafer mark relative to the center of the first wafer coverage area 11 is the same as the orientation of the center of the first pressure head mark 12 relative to the center of the first wafer coverage area 11.

[0080] Since the first relative position of the first wafer mark on the first wafer 101 relative to the shape of the first wafer 101 is the same as the second relative position of the first pressure head mark 12 located in the first wafer coverage area 11 relative to the first wafer coverage area 11, and when the center of the first pressure head mark 12 is located at the center of the field of view of the second camera 40, the center of the first wafer coverage area 11 and the center of the second pressure head 20 are aligned along the first direction Y, it can be determined that when the center of the first wafer mark is located at the center of the field of view of the second camera 40, the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y. Therefore, after the first wafer 101 is fixed in the first wafer coverage area 11, the first position information of the second pressure head 20 when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y can be determined by controlling the movement of the second pressure head 20 and obtaining the field of view of the second camera 40 during the movement of the second pressure head 20.

[0081] It should be noted that the third relative position of the second wafer mark on the second wafer 201 relative to the shape of the second wafer 201 is the same as the fourth relative position of the second pressure head mark 22 relative to the second wafer coverage area 21, meaning that, in the same coordinate system, the orientation of the center of the second wafer mark relative to the center of the second wafer coverage area 21 is the same as the orientation of the center of the second pressure head mark 22 relative to the center of the second wafer coverage area 21.

[0082] Since the third relative position of the second wafer mark on the second wafer 201 relative to the shape of the second wafer 201 is the same as the fourth relative position of the second pressure head mark 22 located outside the second wafer coverage area 21 relative to the second wafer coverage area 21, and when the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30, the center of the second wafer coverage area 21 and the center of the second pressure head 20 are aligned along the first direction Y. However, since the second wafer mark is located within the second wafer coverage area 21 after the second wafer 201 is fixed, and the second wafer mark is not in the field of view of the first camera 30, it is necessary to first control the second pressure head 20 along the second direction (i.e., the second pressure head 20). When the second wafer mark is not moved, the projection of the second wafer mark along the first direction Y points to the projection of the second pressure head mark 22 along the first direction Y. Move the second pressure head 20 a preset distance so that the second wafer mark first appears in the field of view of the first camera 30. Then, by controlling the movement of the second pressure head 20 and obtaining the field of view of the first camera 30 during the movement of the second pressure head 20, the second pressure head 20 is moved to a position that makes the center of the second wafer mark located in the center of the field of view of the first camera 30. Finally, control the second pressure head 20 to move a preset distance in the opposite direction to the second direction. When the center of the second wafer 201 and the center of the second pressure head 20 are aligned along the first direction Y, the first position information of the second pressure head 20 at this time is obtained.

[0083] The technical solution of this invention, by setting the first camera 30 outside the first wafer coverage area 11, the first pressure head mark 12 inside the first wafer coverage area 11, the second camera 40 inside the second wafer coverage area 21, and the second pressure head mark 22 outside the second wafer coverage area 21, and by aligning the center of the second pressure head 20 with the center of the first pressure head 10 along the first direction Y, ensures that the center of the first pressure head mark 12 is located at the center of the field of view of the second camera 40 and the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30, thus enabling the first wafer 101 to be fixed on... After the first wafer covers the area 11, by controlling the movement of the second pressure head 20 and obtaining the field of view of the second camera 40 during the movement of the second pressure head 20, the first position information of the second pressure head 20 when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y can be determined. After the second wafer 201 is fixed in the second wafer covering area 21, by controlling the movement of the second pressure head 20 and obtaining the field of view of the first camera 30 during the movement of the second pressure head 20, the alignment information of the center of the second wafer 201 and the center of the first pressure head 10 along the first direction Y can be determined. The second position information of the second pressure head 20 is obtained. Finally, based on the acquired first and second position information, the movement of the second pressure head 20 can be controlled to align the center of the first wafer 101 with the center of the second wafer 201 along the first direction Y. This eliminates the need for a high-precision second pressure head 20. After the first and second pressure heads 10 and 20 are aligned, by controlling the second pressure head 20 to perform two movements, the deviation between the center of the first wafer 101 and the center of the second wafer 201 can be calculated based on the acquired first and second position information. Then, the movement of the second pressure head 20 can be controlled accordingly. The alignment algorithm is simple and helps to improve alignment accuracy. The alignment accuracy mainly depends on the accuracy of the first camera 30 and the second camera 40. The first camera 30 and the second camera 40 use common high-magnification cameras, which can achieve sub-micron level alignment accuracy. Furthermore, the technical solution of this embodiment does not require the light transmittance of the wafer mark, which helps to increase the number of wafer bonding stacks.

[0084] In one feasible implementation, the first position of the first pressure head 10 is the center of the first pressure head 10, and the second position of the second pressure head 20 is the center of the second pressure head 20. The controller 50 is used to control the second pressure head 20 to move to an initial zero position so that the center of the second pressure head 20 is aligned with the center of the first pressure head 10 along the first direction Y. The controller 50 is used to control the second pressure head 20 to move from the initial zero position until the center of the first wafer 101 is aligned with the center of the second pressure head 20 along the first direction Y. The controller 50 is used to control the second pressure head 20 to move from the initial zero position until the center of the second wafer 201 is aligned with the center of the first pressure head 10 along the first direction Y.

[0085] For example, the controller 50 first controls the second pressure head 20 to move to a position that aligns the center of the second pressure head 20 with the center of the first pressure head 10 along the first direction Y, and sets this position as the initial zero position. Subsequently, moving the second pressure head 20 to align the center of the first wafer 101 with the center of the second pressure head 20 along the first direction Y, or to align the center of the second wafer 201 with the center of the first pressure head 10 along the first direction Y, requires starting the movement from the initial zero position.

[0086] In this embodiment of the invention, by setting the second pressure head 20 to start moving from the initial zero position each time it performs an alignment operation, the movement path planning of the second pressure head 20 can be made simpler, without having to consider the ending position of the previous movement, thus reducing algorithm complexity and improving alignment accuracy.

[0087] In one feasible implementation, refer to Figure 2 and Figure 3 At least one first camera 30 includes two first cameras 30. At least one first pressure head mark 12 includes two first pressure head marks 12. At least one first wafer mark includes two first wafer marks. At least one second camera 40 includes two second cameras 40. At least one second pressure head mark 22 includes two second pressure head marks 22. At least one second wafer mark includes two second wafer marks. The first camera 30 corresponds to the second pressure head mark 22. The second camera 40 corresponds to the first pressure head mark 12.

[0088] For example, in the embodiments of the present invention, the first camera 30 and the second pressure head mark 22 can correspond one-to-one, and the second camera 40 and the first pressure head mark 12 can correspond one-to-one.

[0089] In this embodiment of the invention, by equipping the first pressure head mark 12 of the first pressure head 10 and the second pressure head mark 22 of the second pressure head 20 with independent cameras, errors caused by switching the viewpoint of a single camera can be avoided, which is beneficial to improving alignment accuracy.

[0090] In one feasible embodiment, the first pressure head 10 includes an electrostatic chuck. The second pressure head 20 includes a multi-degree-of-freedom motion platform.

[0091] For example, the first pressure head 10 can use an electrostatic chuck to fix the first wafer 10 to ensure that the first wafer does not detach from the first pressure head 10. The second pressure head 20 can use a multi-degree-of-freedom motion platform such as a UVW motion platform or an XYθ motion platform. Compared with a motion platform that can only achieve planar movement, by using a UVW motion platform or an XYθ motion platform, not only can planar translation be achieved, but rotation can also be achieved, which is more conducive to aligning the pressure head with the wafer, and does not require strict rules on the initial placement position of the wafer.

[0092] This invention also provides a wafer bonding alignment method, which is applied to the wafer bonding alignment apparatus provided in the above embodiments. Figure 6 A flowchart of a wafer bonding alignment method provided in an embodiment of the present invention is shown below. Figure 6 The wafer bonding alignment method in this embodiment of the invention includes:

[0093] S110. Control the movement of the second pressure head so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera.

[0094] For example, refer to Figures 1 to 5 In this embodiment of the invention, a first camera 30 is located outside the first wafer coverage area 11, a first pressure head mark 12 is located inside the first wafer coverage area 11, a second camera 40 is located inside the second wafer coverage area 21, and a second pressure head mark 22 is located outside the second wafer coverage area 21. When the second position of the second pressure head 20 is aligned with the first position of the first pressure head 10 along the first direction Y, the center of the first pressure head mark 12 will be located at the center of the field of view of the second camera 40, and the center of the second pressure head mark 22 will be located at the center of the field of view of the first camera 30. The controller 50 in this embodiment of the invention is communicatively connected to the second pressure head 20, the first camera 30, and the second camera 40, respectively. It can acquire the field of view of the first camera 30 and the field of view of the second camera 40. Therefore, during the control of the movement of the second pressure head 20, it can determine whether the second position of the second pressure head 20 is aligned with the first position of the first pressure head 10 along the first direction Y based on the position of the second pressure head mark 22 in the field of view of the first camera 30 and the position of the first pressure head mark 12 in the field of view of the second camera 40.

[0095] S120. After the first wafer is fixed in the area covered by the first wafer, the second pressure head is controlled to move until the center of the first wafer is aligned with the second position along the first direction, and the first position information of the moved second pressure head is obtained.

[0096] For example, refer to Figures 1 to 5The controller 50 is communicatively connected to the second pressure head 20. After the first wafer 101 is fixed in the first wafer coverage area 11, the controller 50 determines the first position information of the second pressure head 20 when the center of the first wafer 101 is aligned with the second position of the second pressure head 20 along the first direction Y by controlling the movement of the second pressure head 20 and obtaining the field of view of the second camera 40 during the movement of the second pressure head 20.

[0097] S130. After the second wafer is fixed in the area covered by the second wafer, the second pressure head is controlled to move until the center of the second wafer is aligned with the first position along the first direction, and the second position information of the moved second pressure head is obtained.

[0098] For example, refer to Figures 1 to 5 The controller 50 is communicatively connected to the second pressure head 20. After the second wafer 201 is fixed in the second wafer coverage area 21, the controller 50 determines the second position information of the second pressure head 20 when the center of the second wafer 201 is aligned with the first position of the first pressure head 10 along the first direction Y by controlling the movement of the second pressure head 20 and obtaining the field of view of the first camera 30 during the movement of the second pressure head 20.

[0099] S140. Control the movement of the second pressure head according to the first position information and the second position information so that the center of the first wafer and the center of the second wafer are aligned along the first direction.

[0100] For example, refer to Figures 1 to 5 Finally, the controller 50 can control the second pressure head 20 to move according to the acquired first position information and second position information so that the center of the first wafer 101 and the center of the second wafer 201 are aligned along the first direction Y.

[0101] This invention achieves alignment between the first wafer 101 and the second wafer 201 by employing the above-described wafer bonding alignment method. The wafer bonding alignment device that can be used to implement the above-described wafer bonding alignment method can employ a second pressure head 20 with lower motion accuracy. The second pressure head 20 can achieve sub-micron level alignment accuracy by using a micron-level UVW platform combined with image feedback. Furthermore, the controller 50 determines whether the wafer and the corresponding pressure head are aligned by the field of view of the camera. The alignment algorithm is not complicated, which is beneficial to improving alignment accuracy. Moreover, the technical solution of this invention does not require the light transmittance of the wafer mark, which is beneficial to increasing the number of wafer bonding stacks.

[0102] Figure 7 A flowchart of another wafer bonding alignment method provided in an embodiment of the present invention. Figure 7The illustrated embodiment provides a detailed explanation of how to control the movement of the second pressure head to align the second position of the second pressure head with the first position of the first pressure head along a first direction, how to control the movement of the second pressure head until the center of the first wafer is aligned with the second position along the first direction, and how to control the movement of the second pressure head until the center of the second wafer is aligned with the first position along the first direction. It should be noted that in this embodiment, the first position of the first pressure head is the center of the first pressure head, and the second position of the second pressure head is the center of the second pressure head. (Refer to...) Figure 7 The wafer bonding alignment method in this embodiment of the invention includes:

[0103] S210. Control the second pressure head to move to the initial zero position so that the center of the second pressure head is aligned with the center of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera.

[0104] For example, Figure 8 A schematic diagram of the field of view of a first camera when the center of a first pressure head and the center of a second pressure head are aligned along a first direction, as provided in an embodiment of the present invention. Figure 8 The illustrated embodiment uses the example of two second pressure head marks 22 and two first cameras 30, where each first camera 30 corresponds one-to-one with a second pressure head mark 22. Figure 8 Figure (a) shows the position of one of the two second indenter marks 22 in the field of view of the corresponding first camera 30. Figure 8 Figure (b) shows the position of the other of the two second indenter marks 22 in the field of view of the corresponding first camera 30. Figure 8 The label 301 indicates the center of the field of view of the first camera 30. (Reference) Figure 1 The controller 50 is communicatively connected to the second pressure head 20. It can first control the second pressure head 20 to move to a position where the center of the second pressure head 20 is aligned with the center of the first pressure head 10 along the first direction Y, and set this position as the initial zero position. The controller 50 can determine whether the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30 based on the positional relationship between the second mark 22 and the field of view center mark 301 of the first camera 30, and thus determine whether the center of the second pressure head 20 is aligned with the center of the first pressure head 10 along the first direction Y. Figure 8 In Figures (a) and (b), the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30. At this time, the center of the second pressure head 20 is aligned with the center of the first pressure head 10 along the first direction Y. It can be understood that at this time, there are also two first pressure head marks 12 and two second cameras 40. The center of the first pressure head mark 12 is also located at the center of the field of view of the second camera 40.

[0105] S220. After the first wafer is fixed in the area covered by the first wafer, the second pressure head is controlled to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction, and the first position information of the second pressure head after the movement is obtained.

[0106] In one feasible implementation, Figure 9 This is a schematic diagram illustrating the positional relationship between a first wafer and a second pressure head after the first wafer is fixed in the first wafer coverage area, as provided in an embodiment of the present invention. (Refer to...) Figure 2 and Figure 9 The first wafer 101 includes at least one first wafer marker 1011. The first wafer marker 1011 has a first relative position relative to the shape of the first wafer 101, and the first pressure head marker 12 has a second relative position relative to the first wafer coverage area 11. The first relative position and the second relative position are the same. Controlling the second pressure head 20 to move from an initial zero position until the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y includes: controlling the second pressure head 20 to move from an initial zero position until the center of the first wafer marker 1011 is located at the center of the field of view of the second camera 40.

[0107] It should be noted that the first relative position of the first wafer mark 1011 on the first wafer 101 relative to the shape of the first wafer 101 and the second relative position of the first pressure head mark 12 relative to the first wafer coverage area 11 are the same as the second relative position of the first pressure head mark 12 relative to the first wafer coverage area 11 in the same coordinate system.

[0108] Figure 10 This is a schematic diagram illustrating the positional relationship between the first wafer and the second pressure head when the center of the first wafer and the center of the second pressure head are aligned along a first direction, as provided in an embodiment of the present invention. Figure 11 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing the alignment of the center of a first wafer with the center of a second pressure head along a first direction. Figure 12 This invention provides a schematic diagram of the field of view of a first camera when the center of a first wafer and the center of a second pressure head are aligned along a first direction. It should be noted that... Figures 9-12 The illustrated embodiment uses the example of two first wafer markers 1011, two first pressure head markers 12, two second pressure head markers 22, two first cameras 30, and two second cameras 40. The first cameras 30 and second pressure head markers 22 correspond one-to-one, and the second cameras 40 and first wafer markers 1011 correspond one-to-one. Figure 12 Figure (c) shows the position of one of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y. Figure 12 Figure (d) shows the position of the other of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y. Figure 12 The label 301 indicates the center of the field of view of the first camera 30.

[0109] refer to Figures 9-12 Since the first relative position of the first wafer mark 1011 on the first wafer 101 relative to the shape of the first wafer 101 is the same as the second relative position of the first pressure head mark 12 located in the first wafer coverage area 11 relative to the first wafer coverage area 11, and when the center of the first pressure head mark 12 is located at the center of the field of view of the second camera 40, the center of the first wafer coverage area 11 and the center of the second pressure head 20 are aligned along the first direction Y, it can be determined that when the center of the first wafer mark 1011 is located at the center of the field of view of the second camera 40, the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y. Therefore, after the first wafer 101 is fixed in the first wafer coverage area 11, the controller 50 can determine the first position information of the second pressure head 20 when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y by controlling the second pressure head 20 to move from the initial zero position and obtaining the field of view of the second camera 40 during the movement of the second pressure head 20.

[0110] S230. After the second wafer is fixed in the area covered by the second wafer, the second pressure head is controlled to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction, and the second position information of the moved second pressure head is obtained.

[0111] In one feasible implementation, Figure 13 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing how to control the second pressure head to move a preset distance along a second direction from an initial zero position. Figure 14 This is a schematic diagram of a structure provided by an embodiment of the present invention, showing the alignment of the center of the second wafer with the center of the first pressure head along a first direction. (Refer to...) Figure 13 and Figure 14The second wafer 201 includes at least one second wafer marker 2011. The second wafer marker 2011 has a third relative position relative to the shape of the second wafer 201, and the second pressure head marker 22 has a fourth relative position relative to the second wafer coverage area 21. The third relative position and the fourth relative position are the same. Controlling the second pressure head 20 to move from an initial zero position until the center of the second wafer 201 is aligned with the center of the first pressure head 10 along the first direction Y includes: controlling the second pressure head 20 to move a preset distance from the initial zero position along the second direction X, wherein the second direction X is the direction in which the projection of the second wafer marker 2011 along the first direction Y points to the projection of the second pressure head marker 22 along the first direction Y when the second pressure head 20 is not moving; controlling the second pressure head 20 to move until the center of the second wafer marker 2011 is located at the center of the field of view of the first camera 30; and controlling the second pressure head 20 to move a preset distance in a direction opposite to the second direction X.

[0112] It should be noted that the third relative position of the second wafer mark 2011 on the second wafer 201 relative to the shape of the second wafer 201 is the same as the fourth relative position of the second pressure head mark 22 relative to the second wafer coverage area 21, meaning that, in the same coordinate system, the orientation of the center of the second wafer mark 2011 relative to the center of the second wafer coverage area 21 is the same as the orientation of the center of the second pressure head mark 22 relative to the center of the second wafer coverage area 21.

[0113] Figure 15 A schematic diagram of the field of view of a first camera when the center of a second wafer is aligned with the center of a first pressure head along a first direction, as provided in an embodiment of the present invention. Figures 13-15 The illustrated embodiment uses two first wafer markers 1011, two second wafer markers 2011, two first pressure head markers 12, two second pressure head markers 22, two first cameras 30, and two second cameras 40 as examples. Before the second pressure head 20 moves a preset distance along the second direction X from its initial zero position, and when the center of the second wafer 201 is aligned with the center of the first pressure head 10 along the first direction Y, the first camera 30 corresponds one-to-one with the second pressure head marker 22. After the second pressure head 20 moves a preset distance along the second direction X from its initial zero position, the first camera 30 corresponds one-to-one with the second wafer marker 2011. Figure 15 Figure (e) shows the position of one of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the second wafer 201 is aligned with the center of the first pressure head 10 along the first direction Y. Figure 15Figure (f) shows the position of the other of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the second wafer 201 is aligned with the center of the first pressure head 10 along the first direction Y. Figure 15 The label 301 indicates the center of the field of view of the first camera 30.

[0114] refer to Figures 13-15 Since the third relative position of the second wafer mark 2011 on the second wafer 201 relative to the shape of the second wafer 201 is the same as the fourth relative position of the second pressure head mark 22 located outside the second wafer coverage area 21 relative to the second wafer coverage area 21, and when the center of the second pressure head mark 22 is located at the center of the field of view of the first camera 30, the center of the second wafer coverage area 21 and the center of the second pressure head 20 are aligned along the first direction Y. However, since the second wafer mark 2011 is located within the second wafer coverage area 21 after the second wafer 201 is fixed, the second wafer mark 2011 is not in the field of view of the first camera 30. Therefore, the controller 50 First, the second pressure head 20 needs to be controlled to move a preset distance from the initial zero position along the second direction X so that the second wafer mark 2011 appears in the field of view of the first camera 30. Then, the controller 50 controls the movement of the second pressure head 20 and obtains the field of view of the first camera 30 during the movement of the second pressure head 20 to move the second pressure head 20 to a position where the center of the second wafer mark 2011 is located in the center of the field of view of the first camera 30. Finally, the second pressure head 20 is controlled to move a preset distance in the opposite direction to the second direction X. At this time, when the center of the second wafer 201 and the center of the second pressure head 20 are aligned along the first direction Y, the first position information of the second pressure head 20 at this time is obtained.

[0115] S240: Control the movement of the second pressure head according to the first position information and the second position information so that the center of the first wafer is aligned with the center of the second wafer along the first direction.

[0116] As one possible implementation, controlling the movement of the second pressure head 20 according to the first position information and the second position information to align the center of the first wafer 101 with the center of the second wafer 201 along the first direction Y includes: determining the third position information of the second pressure head 20 when the center of the first wafer mark 1011 and the center of the second wafer mark 2011 are aligned along the first direction Y according to the first position information and the second position information; and controlling the movement of the second pressure head 20 according to the third position information.

[0117] For example, taking the second pressure head 20 using an XYθ motion platform, when the center of the first pressure head 10 and the center of the second pressure head 20 are aligned along the first direction Y, the position of the second pressure head 20 is the initial zero position, and the coordinates can be (0, 0, 0); when the center of the first wafer 101 and the center of the second pressure head 20 are aligned along the first direction Y, the position of the second pressure head 20 is the first position, and the first position information corresponding to this first position is the coordinates (X1, Y1, θ1); when the center of the second wafer 201 and the center of the first pressure head 10 are aligned along the first direction Y, the position of the second pressure head 20 is the second position, and the second position information corresponding to this second position is the coordinates (X1, Y1, θ1). The coordinates are (X2, Y2, θ2). At this time, the coordinate difference between the two positions of the second pressure head 20 is the coordinate difference between the first wafer mark 1011 and the second wafer mark 2011. The alignment action can be transformed into the action of the second pressure head 20 moving from the second position to the first position. After the movement, the position of the second pressure head 20 is the third position, and the coordinates corresponding to the third position are (X2-X1, Y2-Y1, θ2-θ1). At this coordinate, the center of the first wafer mark 1011 and the center of the second wafer mark 2011 are aligned along the first direction Y, that is, the center of the first wafer 101 and the center of the second wafer 201 are aligned along the first direction Y.

[0118] Figure 16 A flowchart illustrating another wafer bonding alignment method provided in this embodiment of the invention. Figure 16 The embodiments shown enrich the flow of the wafer bonding alignment method, see reference. Figure 16 The wafer bonding alignment method in this embodiment of the invention includes:

[0119] S310, Control the movement of the second pressure head so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera.

[0120] S320. After the first wafer is fixed in the area covered by the first wafer, the second pressure head is controlled to move until the center of the first wafer is aligned with the second position along the first direction, and the first position information of the moved second pressure head is obtained.

[0121] S330. After the second wafer is fixed in the area covered by the second wafer, the second pressure head is controlled to move until the center of the second wafer is aligned with the first position along the first direction, and the second position information of the moved second pressure head is obtained.

[0122] S340. Control the movement of the second pressure head according to the first position information and the second position information so that the center of the first wafer is aligned with the center of the second wafer along the first direction.

[0123] S350. Determine a virtual marker based on the first position information and the second position information, wherein the center of the virtual marker is located at the center of the field of view of the first camera.

[0124] Figure 17 This is a schematic diagram of the field of view of a first camera when the first pressure head moves in the direction from the first pressure head toward the second pressure head, as provided in an embodiment of the present invention. Figure 17 The illustrated embodiment uses the following example: a first wafer marker 1011 includes two first wafer markers 1011; a second wafer marker 2011 includes two second wafer markers 2011; a first pressure head marker 12 includes two first pressure head markers 12; a second pressure head marker 22 includes two second pressure head markers 22; a first camera 30 includes two first cameras 30; and a second camera 40 includes two second cameras 40. The first camera 30 corresponds one-to-one with the second pressure head marker 22. Figure 17 Figure (g) shows the position of one of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the first wafer 101 and the center of the second wafer 201 are aligned along the first direction Y. Figure 17 Figure (h) shows the position of the other of the two second pressure head marks 22 in the field of view of the corresponding first camera 30 when the center of the first wafer 101 and the center of the second wafer 201 are aligned along the first direction Y. Figure 17 The label 301 indicates the field of view center marker of the first camera 30, and 22' indicates a virtual marker. There are two virtual markers 22', located at the field of view centers of the two first cameras 30 respectively.

[0125] S360. During the process of controlling the first pressure head to move in the direction from the first pressure head toward the second pressure head, the movement of the first pressure head is adjusted according to the position of the center of the virtual mark in the field of view of the first camera.

[0126] For example, the controller 50 is also communicatively connected to the first pressure head 10. Figure 1 (Not shown in the image) During the bonding process, that is, when the controller 50 controls the first pressure head 10 to move in the direction of the first pressure head 10 toward the second pressure head 20, the movement of the first pressure head 10 can be adjusted by keeping the virtual mark 22' always in the center of the field of view of the first camera 30 as a mark for the wafer marker to always be aligned. This can solve the problem of wafer misalignment of the first wafer 101 and the second wafer 201 during the pressing bonding process after the opaque wafer is aligned.

[0127] Based on the same inventive concept, embodiments of the present invention also provide a wafer bonding machine, which includes the wafer bonding alignment device shown in any of the above embodiments of the present invention.

[0128] The wafer bonding machine in this embodiment of the invention includes the wafer bonding alignment device provided in any of the above embodiments of the invention. Therefore, the wafer bonding machine includes the technical features of the wafer bonding alignment device and has the beneficial effects of the wafer bonding alignment device. The similarities can be referred to the description above.

[0129] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A wafer bonding alignment apparatus, characterized by, It includes a first pressure head, a second pressure head, at least one first camera, at least one second camera, and a controller; the first pressure head and the second pressure head are arranged opposite to each other along a first direction; The surface of the first pressure head near the second pressure head includes a first wafer coverage area for carrying the first wafer and at least one first pressure head mark; the first camera is located outside the first wafer coverage area, and the first pressure head mark is located within the first wafer coverage area; The second pressure head has a surface near the first pressure head that includes a second wafer coverage area for carrying the second wafer and at least one second pressure head mark; the second camera is located within the second wafer coverage area, and the second pressure head mark is located outside the second wafer coverage area; The controller is communicatively connected to the second pressure head and is used to control the movement of the second pressure head so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera; The controller is further configured to, after the first wafer is fixed in the area covered by the first wafer, control the second pressure head to move until the center of the first wafer is aligned with the second position along the first direction, and obtain the first position information of the second pressure head after the movement; The controller is further configured to, after the second wafer is fixed in the area covered by the second wafer, control the second pressure head to move until the center of the second wafer is aligned with the first position along the first direction, and obtain the second position information of the second pressure head after the movement; The controller is further configured to control the movement of the second pressure head according to the first position information and the second position information so that the center of the first wafer and the center of the second wafer are aligned along the first direction.

2. The wafer bonding alignment apparatus of claim 1, wherein, The first position is the center of the first pressure head; the second position is the center of the second pressure head; The controller is used to control the second pressure head to move to the initial zero position so that the center of the second pressure head is aligned with the center of the first pressure head along the first direction; The controller is used to control the second pressure head to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction; The controller is used to control the second pressure head to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction.

3. The wafer bonding alignment apparatus of claim 1, wherein, The first wafer includes at least one first wafer marker; the first wafer marker has a first relative position relative to the shape of the first wafer, and the first pressure head marker has a second relative position relative to the area covered by the first wafer; the first relative position and the second relative position are the same; The second wafer includes at least one second wafer marker; The second wafer mark has a third relative position relative to the shape of the second wafer, and the second pressure head mark has a fourth relative position relative to the area covered by the second wafer; the third relative position is the same as the fourth relative position.

4. The wafer bonding alignment apparatus of claim 3, wherein, At least one first camera includes two first cameras; at least one first pressure head mark includes two first pressure head marks; at least one first wafer mark includes two first wafer marks; At least one second camera includes two second cameras; at least one second pressure head mark includes two second pressure head marks; at least one second wafer mark includes two second wafer marks; The first camera corresponds to the second pressure head mark; the second camera corresponds to the first pressure head mark.

5. The wafer bonding alignment apparatus of claim 1, wherein, The first pressure head includes an electrostatic chuck; The second pressure head includes a multi-degree-of-freedom motion platform.

6. A wafer bonding alignment method applied to the wafer bonding alignment apparatus of any one of claims 1-5, characterized in that, The wafer bonding alignment method includes: The second pressure head is controlled to move so that the second position of the second pressure head is aligned with the first position of the first pressure head along the first direction, wherein the center of the first pressure head mark is located at the center of the field of view of the second camera, and the center of the second pressure head mark is located at the center of the field of view of the first camera; After the first wafer is fixed in the area covered by the first wafer, the second pressure head is controlled to move until the center of the first wafer is aligned with the second position along the first direction, and the first position information of the second pressure head after the movement is obtained; After the second wafer is fixed in the area covered by the second wafer, the second pressure head is controlled to move until the center of the second wafer is aligned with the first position along the first direction, and the second position information of the second pressure head after the movement is obtained; The second pressure head is controlled to move according to the first position information and the second position information so that the center of the first wafer and the center of the second wafer are aligned along the first direction.

7. The wafer bonding alignment method of claim 6, wherein, The first position is the center of the first pressure head; the second position is the center of the second pressure head; Controlling the movement of the second pressure head to align the second position of the second pressure head with the first position along the first direction includes: Control the second pressure head to move to the initial zero position so that the center of the second pressure head is aligned with the center of the first pressure head along the first direction; Controlling the movement of the second pressure head until the center of the first wafer and the center of the second pressure head are aligned along the first direction includes: The second pressure head is controlled to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction; Controlling the movement of the second pressure head until the center of the second wafer is aligned with the center of the first pressure head along the first direction includes: The second pressure head is controlled to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction.

8. The wafer bonding alignment method according to claim 7, characterized in that, The first wafer includes at least one first wafer marker; the first wafer marker has a first relative position relative to the shape of the first wafer, and the first pressure head marker has a second relative position relative to the area covered by the first wafer; the first relative position and the second relative position are the same; The second wafer includes at least one second wafer marker; The second wafer mark has a third relative position relative to the shape of the second wafer, and the second pressure head mark has a fourth relative position relative to the area covered by the second wafer; the third relative position and the fourth relative position are the same. Controlling the second pressure head to move from the initial zero position until the center of the first wafer and the center of the second pressure head are aligned along the first direction includes: The second pressure head is controlled to move from the initial zero position until the center of the first wafer mark is located at the center of the field of view of the second camera; Controlling the second pressure head to move from the initial zero position until the center of the second wafer is aligned with the center of the first pressure head along the first direction includes: The second pressure head is controlled to move a preset distance from the initial zero position along the second direction, wherein the second direction is the direction in which the projection of the second wafer mark along the first direction points to the projection of the second pressure head mark along the first direction when the second pressure head is not moved; Control the movement of the second pressure head until the center of the second wafer mark is located at the center of the field of view of the first camera; Control the second pressure head to move the preset distance in a direction opposite to the second direction.

9. The wafer bonding alignment method according to claim 6, characterized in that, After controlling the movement of the second pressure head according to the first position information and the second position information to align the center of the first wafer with the center of the second wafer along the first direction, the wafer bonding alignment method further includes: A virtual marker is determined based on the first location information and the second location information, wherein the center of the virtual marker is located at the center of the field of view of the first camera; During the process of controlling the first pressure head to move in the direction from the first pressure head toward the second pressure head, the movement of the first pressure head is adjusted according to the position of the center of the virtual mark in the field of view of the first camera.

10. A wafer bonding machine, characterized in that, Includes the wafer bonding alignment apparatus as described in any one of claims 1-5.

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