Wafer bonding device used in vacuum environment
By designing a wafer bonding device for vacuum environments, and using the camera to identify the wafer reference points to achieve alignment and clamping, the problem of poor accuracy caused by the relative displacement of wafers in traditional devices is solved, and the yield and bonding quality are improved.
Patent Information
- Application Number
- CN202422114583.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-30
- Publication Date
- 2025-06-10
- Estimated Expiration
- 2034-08-30
AI Technical Summary
Traditional wafer bonding devices are difficult to achieve high-precision alignment in vacuum environments, resulting in relative displacement between wafers and affecting yield.
A wafer bonding device including a press head, a first camera, a stage, a second camera and a robot is designed. The wafer to be bonded is placed on the stage by a robot, and the reference points on the wafer are identified by two cameras to achieve alignment and clamping.
It improves the yield rate of wafer bonding, reduces processing costs, saves wafer material costs, and reduces impurities and pollution in a vacuum environment, improving the quality and reliability of bonding.
Smart Images
Figure CN222966076U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of wafer bonding, and particularly relates to a wafer bonding device for a vacuum environment. Background Art
[0002] With the development of the electronics industry, the wafer bonding process can achieve higher-layer stacking of devices, thus attracting more and more attention. However, due to the short development history of wafer bonding devices, there are still many deficiencies compared with other semiconductor devices.
[0003] The traditional method more often adopts a pre-positioning method, that is, two wafers to be bonded are respectively positioned. After the positioning is completed, the wafer and the chuck enter the bonding station at the same time. Since there will be relative displacement between the two pre-aligned wafers, the alignment accuracy is affected. Once there is relative displacement between the two wafers and the bonding station cannot detect and judge, the yield rate of the bonded good wafers will be greatly reduced. Summary of the Utility Model
[0004] The utility model provides a wafer bonding device for a vacuum environment to solve the above technical problems.
[0005] The technical solution for the utility model to solve the above technical problems is as follows: A wafer bonding device for a vacuum environment includes a pressing head, a first camera, a stage, a second camera and a manipulator. The pressing head is connected to a driving device and moves up and down under the action of the driving device. The pressing head is used to press two or more wafers to be bonded. The stage is located below the pressing head, and the stage is used to position and clamp the wafers to be bonded. The first camera is used to take pictures of the reference points of the wafers to be bonded on the stage and obtain the coordinate positions of the reference points. The manipulator is located on one side of the stage, and the manipulator is used to convey the wafers to be bonded to the stage. The second camera is located on the conveying path of the wafers to be bonded, and the second camera is used to take pictures of the reference points of the wafers to be bonded on the manipulator and obtain the coordinate positions of the reference points.
[0006] On the basis of the above technical solution, the utility model can further make the following improvements to the above technical solution:
[0007] Preferably, both the first camera and the second camera are industrial measurement cameras.
[0008] Preferably, the wafers to be bonded include a first wafer to be bonded and a second wafer to be bonded. A first reference point is provided on the first wafer to be bonded, and a second reference point is provided on the second wafer to be bonded.
[0009] Preferably, an adjustment mechanism is further included. The adjustment mechanism includes a plurality of adjustment cylinders. A wafer adsorption gasket is provided on the carrier table. The plurality of adjustment cylinders are evenly arranged circumferentially along the wafer adsorption gasket. The plurality of adjustment cylinders are used to adjust the position of the wafer to be bonded on the carrier table.
[0010] Preferably, pressing mechanisms are symmetrically provided on both sides of the wafer adsorption gasket. The pressing mechanisms are used to press two or more wafers to be bonded.
[0011] The beneficial effects of the present utility model are as follows: Two or more wafers to be bonded are placed on the carrier table by a manipulator, and the reference points on the wafers are identified by two cameras, so as to align and clamp two or more wafers to be bonded, solving the problem that the relative displacement between wafers caused by the separate pre-positioning of two or more wafers in the prior art results in poor alignment accuracy and affects the yield. The wafer bonding device can improve the yield of wafer bonding, reduce the processing cost, and save the wafer material cost. Description of the Drawings
[0012] Figure 1 is a schematic diagram of the wafer bonding device of the present utility model;
[0013] Figure 2 is a top view of the wafers to be bonded when pressed in the present utility model.
[0014] The reference numerals are recorded as follows: 1, pressure head; 2, first camera; 3, carrier table; 4, second camera; 5, first wafer to be bonded; 6, second wafer to be bonded; 7, manipulator; 8, pressing head; 9, wafer adsorption gasket; 10, corner pressing cylinder; 11, adjustment cylinder; 12, adjustment head. Detailed Embodiments
[0015] The principles and features of the present utility model are described below with reference to the accompanying drawings. The examples given are only used to explain the present utility model and are not intended to limit the scope of the present utility model.
[0016] Such as Figure 1 And Figure 2As shown in the figure, the utility model discloses a wafer bonding device for vacuum environment, which includes a control system and a pressure head 1, a first camera 2, a stage 3, a second camera 4 and a manipulator 7 that are electrically connected to the control system. The pressure head 1 is connected to a driving device and moves up and down under the action of the driving device. The pressure head 1 is used to press two or more wafers to be bonded. The driving device can be a hydraulic device, a pneumatic device or an electric device. The pressure output of the gas source or hydraulic source can be adjusted to adjust the pressing force of the pressure head 1 to meet the requirements of wafer bonding. In this embodiment, it is used to press two wafers to be bonded, namely the first wafer to be bonded 5 and the second wafer to be bonded 6. The stage 3 is located below the pressure head 1. The stage 3 is used to position and clamp the wafers to be bonded. The first camera 2 is installed on a moving device and moves under the drive of the moving device. The moving device can be a cylinder or a hydraulic cylinder. The first camera 2 is used to take pictures of the reference points of the wafers to be bonded on the stage 3 and obtain the coordinate positions of the reference points. The manipulator 7 is located on one side of the stage 3. The manipulator 7 is used to convey the wafers to be bonded to the stage 3. The second camera 4 is located on the conveying path of the wafers to be bonded. The second camera 4 is used to take pictures of the reference points of the wafers to be bonded on the manipulator 7 and obtain the coordinate positions of the reference points. Both the first camera 2 and the second camera 4 are industrial measurement cameras, so as to accurately obtain the images of the reference points and calculate the positions of the coordinate points through the control system. The first wafer to be bonded 5 is placed on the stage 3 by the manipulator 7, and the adjustment mechanism pre-positions the first wafer to be bonded 5. Then, the first camera 2 identifies and obtains the position of the first reference point on the first wafer to be bonded 5. Then, the manipulator 7 places the second wafer to be bonded 6 at the second camera 4. The second camera 4 identifies and obtains the position of the second reference point on the second wafer to be bonded 6. The control system controls the manipulator 7 to align the second wafer to be bonded 6 with the first wafer to be bonded 5 and presses them through the pressing mechanism. Then, the pressure head 1 presses the two wafers to complete the bonding of the wafers. By aligning the two wafers to be bonded and then pressing them, the problem that the relative displacement between wafers caused by the separate pre-positioning of two or more wafers in the prior art results in poor alignment accuracy and affects the yield rate is solved. This wafer bonding device can significantly improve the yield rate of wafer bonding and save processing costs.
[0017] Placing this wafer bonding device in a vacuum environment can reduce impurities and contamination, improve the quality and reliability of bonding, reduce the presence of gas, reduce the possibility of forming bubbles at the bonding interface, and improve the integrity and electrical performance of bonding.
[0018] In this embodiment, there are two wafers to be bonded. The wafers to be bonded include a first wafer to be bonded 5 and a second wafer to be bonded 6. A first reference point is provided on the first wafer to be bonded 5, and a second reference point is provided on the second wafer to be bonded 6. Both the first reference point and the second reference point are cross-shaped.
[0019] The wafer bonding device for a vacuum environment further includes an adjustment mechanism. The adjustment mechanism includes a plurality of adjustment cylinders 11. The adjustment cylinders are electrically connected to the control system. A wafer adsorption gasket 9 is provided on the carrier stage 3. The plurality of adjustment cylinders 11 are evenly arranged circumferentially along the wafer adsorption gasket 9. The plurality of adjustment cylinders 11 are used to adjust the position of the wafers to be bonded on the carrier stage 3. In this embodiment, the adjustment cylinder 11 is used to adjust the position of the first wafer to be bonded 5 on the carrier stage 3. When there is a deviation between the coordinate position of the first reference point on the first wafer to be bonded 5 and the preset position in the control system, the adjustment cylinder 11 adjusts the position of the first wafer to be bonded 5 to the specified position according to the deviation value. In this embodiment, there are three adjustment cylinders 11. The output end of each adjustment cylinder 11 is connected with an adjustment head 12. The adjustment cylinder 11 drives the adjustment head 12 to contact the outer edge of the first wafer to be bonded 5, and drives the first wafer to be bonded 5 to move through the adjustment head 12, so that the first reference point of the first wafer to be bonded 5 is located at the specified position, ensuring the alignment of the subsequent two wafers.
[0020] Pressing mechanisms are symmetrically provided on both sides of the wafer adsorption gasket 9. The pressing mechanisms are used to press two or more wafers to be bonded. The pressing mechanism includes a corner pressing cylinder 10 and a pressing head 8. The corner pressing cylinder 10 is electrically connected to the control system. The pressing head 8 is installed at the output end of the corner pressing cylinder 10. After two or more wafers to be bonded are aligned, the corner pressing cylinder 10 drives the pressing head 8 to press two or more wafers to be bonded, solving the problem of relative movement between two or more wafers and improving the good wafer rate of wafer bonding. Among them, the pressing head 8 presses the non-circuit area on the wafer to avoid damaging the circuit, further improving the yield of wafer bonding, and adjusting the pressing force of the pressing head 8 by adjusting the pressure output of the corner pressing cylinder 10 to ensure that there is no relative movement between two or more wafers to be bonded; and an avoidance space for avoiding the pressing head 8 is provided on the pressing head 1 to avoid interference between the pressing head 1 and the pressing head 8 and ensure normal wafer bonding.
[0021] The usage process of the wafer bonding device for a vacuum environment of the present utility model is as follows:
[0022] Step S1: The manipulator 7 adsorbs the first wafer to be bonded 5 through a suction cup and transports the first wafer to be bonded 5 to the wafer adsorption gasket 9 on the carrier stage 3.
[0023] Step S2: The control system controls the moving device to drive the first camera 2 to move to a specified position, which is directly above the first wafer to be bonded 5. The first camera 2 takes a picture of the first reference point on the first wafer to be bonded 5 and obtains the coordinate position of this first reference point. The moving device drives the first camera 2 to return to the initial position;
[0024] It further includes step S21: The control system matches and calibrates the actual coordinates of the first wafer to be bonded 5 taken by the first camera 2 with the predetermined coordinates. If there is a deviation between the two, the adjustment mechanism adjusts the position of the first wafer to be bonded 5 to the specified position according to the deviation value, and the wafer adsorption gasket 9 adsorbs the first wafer to be bonded 5.
[0025] Step S3: The manipulator 7 adsorbs the second wafer to be bonded 6 through a suction cup and moves the second wafer to be bonded 6 to the second camera 4, that is, moves the second wafer to be bonded 6 directly above the second camera 4. The second camera 4 takes a picture of the second reference point on the second wafer to be bonded 6 and obtains the coordinate position of this second reference point.
[0026] Among them, obtaining the coordinate positions of the first reference point and the second reference point includes the following steps:
[0027] 1) Image preprocessing: Denoise and enhance the contrast of the images of the first wafer to be bonded 5 and the second wafer to be bonded 6 respectively to improve the effect of subsequent image processing;
[0028] 2) Image segmentation of the first reference point and the second reference point respectively: Use threshold segmentation or edge detection to segment the images of the first reference point and the second reference point from the background, and the segmented images of the first reference point and the second reference point will be used as the input for subsequent processing;
[0029] 3) Reference point positioning: Determine the positions of the first reference point and the second reference point by performing geometric analysis and feature extraction on the images of the first reference point and the second reference point; Geometric analysis includes detecting geometric features such as the edges and corners of the first reference point and the second reference point, and feature extraction includes extracting features such as the texture and color of the images of the first reference point and the second reference point. By comprehensively analyzing these features, the positions of the first reference point and the second reference point can be accurately located;
[0030] 4) Coordinate transformation: Convert the positions of the first reference point and the second reference point in the image coordinate system to the positions in the wafer coordinate system. Specifically, by measuring the positional relationship between the first wafer to be bonded 5 and the first camera 2 and the positional relationship between the second wafer to be bonded 6 and the second camera 4, the coordinate transformation is realized.
[0031] Step S4: The control system calculates the relative position between the first reference point and the second reference point according to the coordinate positions of the first reference point and the second reference point, and controls the movement of the manipulator 7 according to this relative position to align the second reference point of the second wafer to be bonded 6 with the first reference point of the first wafer to be bonded 5;
[0032] Among them, assuming that the coordinates of the first reference point are (x 1 , y 1 , z 1 ), and the coordinates of the second reference point are (x 2 , y 2 , z 2 ), then the relative position between the two reference points is:
[0033] Relative displacement in the x direction: Δx = x 2 - x 1 :
[0034] Relative displacement in the y direction: Δy = y 2 - y 1 ;
[0035] Relative displacement in the z direction: Δz = z 2 - z 1 ;
[0036] The control system controls the manipulator 7 to move in the X, Y, and Z directions respectively, so that the second reference point of the second wafer to be bonded 6 is aligned with the first reference point of the first wafer to be bonded 5.
[0037] Step S5: The pressing mechanism on the carrier 3 presses the aligned first wafer to be bonded 5 and the second wafer to be bonded 6, that is, the corner pressing cylinder 10 drives the pressing head 8 to press the first wafer to be bonded 5 and the second wafer to be bonded 6, avoiding relative movement between the two wafers to be bonded and ensuring the bonding yield.
[0038] Step S6: The pressing head 1 presses the first wafer to be bonded 5 and the second wafer to be bonded 6 under the drive of the driving device to complete the bonding of the wafers.
[0039] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A wafer bonding device for use in a vacuum environment, characterized in that: The invention comprises a pressing head (1), a first camera (2), a stage (3), a second camera (4) and a manipulator (7); the pressing head (1) is connected to a driving device and rises and falls under the action of the driving device; the pressing head (1) is used for pressing two or more wafers to be bonded; the stage (3) is located below the pressing head (1); the stage (3) is used for positioning and clamping the wafers to be bonded; the first camera (2) is used for photographing the reference point of the wafer to be bonded on the stage (3) and obtaining the coordinate position of the reference point; the manipulator (7) is located on one side of the stage (3); the manipulator (7) is used for conveying the wafer to be bonded to the stage (3); the second camera (4) is located on the conveying path of the wafer to be bonded; the second camera (4) is used for photographing the reference point of the wafer to be bonded on the manipulator (7) and obtaining the coordinate position of the reference point.
2. The wafer bonding device for use in a vacuum environment according to claim 1, characterized in that: The first camera (2) and the second camera (4) are both industrial measurement cameras.
3. The wafer bonding device for use in a vacuum environment according to claim 1 or 2, characterized in that: The wafers to be bonded comprise a first wafer to be bonded (5) and a second wafer to be bonded (6); the first wafer to be bonded (5) is provided with a first reference point, and the second wafer to be bonded (6) is provided with a second reference point.
4. The wafer bonding device for use in a vacuum environment according to claim 3, characterized in that: It also includes an adjustment mechanism, which includes a plurality of adjustment cylinders (11). A wafer adsorption pad (9) is provided on the stage (3). The plurality of adjustment cylinders (11) are evenly arranged along the circumference of the wafer adsorption pad (9). The plurality of adjustment cylinders are used to adjust the position of the wafer to be bonded on the stage (3).
5. The wafer bonding device for use in a vacuum environment according to claim 4, characterized in that: The wafer adsorption pad (9) is symmetrically provided with clamping mechanisms on both sides, and the clamping mechanisms are used to clamp two or more wafers to be bonded.