A wafer bonding system and a wafer bonding method

Abstract

This application provides a wafer bonding system and method, relating to the field of semiconductor technology. The wafer bonding system and method address the problem that uncompensated positional deviations after the upper wafer is attached to the upper wafer chuck, leading to the plunger deviating from the wafer center and causing asymmetrical propagation of the bonding wave, can not be compensated for. Before bonding, a detection system detects the positional offset between the center of the upper wafer and the center of the upper wafer chuck. Then, a first moving mechanism drives the plunger horizontally to directly above the wafer center, ensuring symmetrical propagation of the bonding wave from the wafer center. The first moving mechanism uses a piezoelectric ceramic drive motor in conjunction with a flexible hinge structure to achieve micron-level displacement compensation. The wafer bonding system and method can improve wafer bonding quality and are used in semiconductor 3D stacking packaging processes.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to a wafer bonding system and a wafer bonding method. Background Technology

[0002] With the development of 3D stacking technology, advanced stacking technology is becoming increasingly important. For high-precision fusion bonding equipment, the current common technical approach is to use edge alignment and a plunger to press down on the center of the wafer, causing the wafer to deform and the bonding wave to spread from the center outwards, forming a bonding process from the center to the edge.

[0003] However, while the upper and lower wafers can have their edge alignment accuracy dynamically adjusted through edge alignment, the positional deviation of the upper wafer relative to the upper wafer chuck after it is attracted to the chuck cannot be compensated for. When the plunger located at the center of the upper wafer chuck depresses, it uses the physical center of the upper wafer chuck as the starting point to press down on the upper wafer. However, the physical center of the upper wafer chuck and the physical center of the upper wafer are often not completely aligned. This leads to a non-central initiation and asymmetric propagation of the bonding wave. Summary of the Invention

[0004] This application provides a wafer bonding system and a wafer bonding method that can ensure that the bonding wave propagates symmetrically from the center of the wafer, thereby improving the quality of wafer bonding.

[0005] One aspect of this application provides a wafer bonding system, comprising: a chamber; a base disposed in the chamber; a lower wafer chuck supported on the base, the lower wafer chuck being used to fix a lower wafer; an upper wafer chuck disposed on the upper part of the chamber, the upper wafer chuck being used to fix an upper wafer, the upper wafer chuck having a through hole at its center; a plunger disposed in the through hole, used to press down the upper wafer to bond with the lower wafer; a first moving mechanism configured to control the plunger to move horizontally in the through hole; a detection system disposed on the upper part of the chamber, the detection system being used to detect the positional offset between the center of the upper wafer and the center of the upper wafer chuck; and a control center communicatively connected to the detection system and the first moving mechanism, the control center being used to receive the detection results of the detection system and control the first moving mechanism according to the detection results.

[0006] In some embodiments of this application, the wafer bonding system further includes: a base disposed above the upper wafer chuck, and a plunger disposed on the base and extending into the through hole from below the base.

[0007] In some embodiments of this application, the first moving mechanism includes: a stator disposed on the upper surface of the upper wafer chuck and surrounding the base; four piezoelectric ceramic drive motors evenly disposed on the inner wall of the stator; and four flexible hinge structures respectively connecting each piezoelectric ceramic drive motor and the side wall of the base, wherein the piezoelectric ceramic drive motor is configured to drive the corresponding flexible hinge structure to move the base.

[0008] In some embodiments of this application, the method by which the control center receives the detection results of the detection system and controls the first moving mechanism according to the detection results includes: the control center controls the first moving mechanism to control the base to move and drive the plunger to move directly above the upper wafer center according to the positional offset between the upper wafer center and the upper wafer chuck center.

[0009] In some embodiments of this application, the bonding system further includes: a second moving mechanism for moving the upper wafer chuck; the control center is also used to control the second moving mechanism.

[0010] In some embodiments of this application, the bonding system further includes: a third moving mechanism for controlling the piston to move in the vertical direction; the control center is also used to control the third moving mechanism.

[0011] In some embodiments of this application, the cross-sectional shape of the through hole includes a circle or a square.

[0012] In some embodiments of this application, the diameter of the through hole is 12 to 15 mm or the side length of the through hole is 12 to 15 mm.

[0013] Another aspect of this application provides a wafer bonding method, comprising: detecting the positional offset between the center of an upper wafer and the center of an upper wafer chuck; and controlling a plunger located in a through hole at the center of the upper wafer chuck to move horizontally according to the detection result, the plunger being used to press down the upper wafer to bond with a lower wafer.

[0014] In some embodiments of this application, a method for controlling the plunger in the through hole located at the center of the upper wafer chuck to move horizontally according to the detection result includes: controlling the plunger to move directly above the center of the upper wafer according to the positional offset between the center of the upper wafer and the center of the upper wafer chuck.

[0015] In some embodiments of this application, the bonding method further includes: moving the upper wafer chuck so that the upper wafer and the lower wafer on the lower wafer chuck are aligned in the vertical direction.

[0016] In some embodiments of this application, the bonding method further includes: controlling the plunger to move vertically and press down on the upper wafer center so that the upper wafer center is in contact with the lower wafer center.

[0017] This application provides a wafer bonding system and a wafer bonding method. Before bonding, the system detects the positional offset between the center of the upper wafer and the center of the upper wafer chuck. Then, the first moving mechanism moves the plunger to ensure that the plunger is directly above the center of the upper wafer. This ensures that the bonding wave propagates symmetrically from the center of the wafer, thereby improving the quality of wafer bonding. Attached Figure Description

[0018] The following accompanying drawings describe in detail the exemplary embodiments disclosed in this application. The same reference numerals denote similar structures in several views of the drawings. Those skilled in the art will understand that these embodiments are non-limiting and exemplary, and the drawings are for illustrative purposes only and are not intended to limit the scope of this application. Other embodiments may similarly fulfill the inventive intent of this application. It should be understood that the drawings are not drawn to scale. Wherein: Figure 1 This is a schematic diagram of the wafer bonding system described in some embodiments of this application; Figure 2 This is a schematic diagram of the structure of the first moving mechanism of the wafer bonding system described in some embodiments of this application. Detailed Implementation

[0019] The following description provides specific application scenarios and requirements for this application, intended to enable those skilled in the art to make and use the content of this application. Various partial modifications to the disclosed embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of this application. Therefore, this application is not limited to the embodiments shown, but rather to the widest scope consistent with the claims.

[0020] The technical solution of this application will be described in detail below with reference to the embodiments and accompanying drawings.

[0021] Figure 1 This is a schematic diagram of the wafer bonding system described in some embodiments of this application. The wafer bonding system described in some embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0022] refer to Figure 1As shown, this application provides a wafer bonding system 100, including: a chamber 110; a base 120 disposed in the chamber 110; a lower wafer chuck 130 supported on the base 120, the lower wafer chuck 130 being used to fix a lower wafer 131; an upper wafer chuck 140 disposed on the upper part of the chamber 110, the upper wafer chuck 140 being used to fix an upper wafer 141, the upper wafer chuck 140 having a through hole at its center; a plunger 151 disposed in the through hole, used to press down the upper wafer 141 to bond with the lower wafer 131; a base 150 disposed above the upper wafer chuck 140, the plunger 151 being disposed on the base 150 and extending from below the base 150 into the through hole; and a first moving mechanism 160 ( Figure 1 The first moving mechanism 160 is only a schematic diagram; for detailed structure, please refer to [reference needed]. Figure 2 The device is configured to control the movement of the base 150, thereby driving the plunger 151 to move horizontally in the through hole; a detection system 170 is disposed on the upper part of the chamber 110, and the detection system 170 is used to detect the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140; a control center (not shown in the figure) is communicatively connected to the detection system 170 and the first moving mechanism 160, and the control center is used to receive the detection results of the detection system 170 and control the first moving mechanism 160 according to the detection results.

[0023] Specifically, in some embodiments of this application, the method by which the control center receives the detection result of the detection system 170 and controls the first moving mechanism 160 according to the detection result includes: the control center controls the first moving mechanism 160 to control the base 150 to move and drive the plunger 151 to move directly above the center of the upper wafer 141 according to the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140.

[0024] In a conventional bonding machine, after the upper wafer 141 is attracted onto the upper wafer chuck 140, the positions of the upper wafer 141 and the upper wafer chuck 140 may not be perfectly aligned. That is, the centers of the upper wafer 141 and the upper wafer chuck 140 may not coincide. However, in a conventional bonding machine, the plunger 151 is usually fixed at the center of the upper wafer chuck 140. This results in the plunger 151 not being located at the center of the upper wafer 141. During subsequent bonding, the plunger 151 is not pressed down at the center of the upper wafer 141. Therefore, the starting point of the bonding wave is not at the center of the wafer, which will affect the bonding quality. In the technical solution of this application, the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140 is first detected by the detection system 170. Then, the positional offset is compensated by the moving base 150 through the first moving mechanism 160 so that the position of the plunger 151 is located at the center of the upper wafer 141. During subsequent bonding, the plunger 151 presses down on the center of the upper wafer 141 to start bonding. The bonding wave propagates symmetrically from the center of the wafer as the starting point, which can improve the wafer bonding quality.

[0025] In some embodiments of this application, the lower wafer chuck 130 can fix the lower wafer 131 in any manner, including but not limited to vacuum adsorption or electrostatic adsorption. In some embodiments of this application, the upper wafer chuck 140 can fix the upper wafer 141 in any manner, including but not limited to vacuum adsorption or electrostatic adsorption.

[0026] In some embodiments of this application, the cross-sectional shape of the through hole includes a circle or a square. In some embodiments of this application, the diameter of the through hole is 12 to 15 mm or the side length of the through hole is 12 to 15 mm. The size of the through hole is sufficient to meet the position compensation of the plunger 151. In some embodiments, the diameter of the plunger 151 is less than or equal to 10 mm, and the plunger 151 has at least 2 to 5 mm of movement space, which is sufficient to meet the movement requirements of the plunger 151.

[0027] refer to Figure 2 As shown, Figure 2 This is a top view of the first moving mechanism 160. In some embodiments of this application, the first moving mechanism 160 includes: a stator 161 disposed on the upper surface of the upper wafer chuck 140 and surrounding the base 150; four piezoelectric ceramic drive motors 162 evenly disposed on the inner wall of the stator 161; and four flexible hinge structures 163 respectively connecting each piezoelectric ceramic drive motor 162 to the side wall of the base 150, wherein the piezoelectric ceramic drive motor 162 is configured to drive the corresponding flexible hinge structure 163 to move the base 150.

[0028] Specifically, the base 150 has a square cross-section, for example, and the stator 161 matches the cross-sectional shape of the base 150. The stator 161 is, for example, a rectangular shape, surrounding the sides of the base 150, and is fixed to the upper wafer chuck 140. To reduce friction, the base 150 is configured to float above the upper wafer chuck 140. The base 150 can be an air-bearing structure or a magnetic levitation structure. For example, air holes can be opened at corresponding positions above the upper wafer chuck 140 to blow air upwards, causing the base 150 to float. Alternatively, magnetic structures with opposite magnetic poles can be provided at corresponding positions on the upper surface of the upper wafer chuck 140 and the lower surface of the base 150 to achieve magnetic levitation using magnetic force. Specifically, any structure capable of suspending the base 150 above the upper wafer chuck 140 can be used. A piezoelectric ceramic drive motor is used to provide power, and the sensitivity of the piezoelectric ceramic drive motor can reach the micrometer level, meeting the movement requirements of the base 150. Flexible hinge structures are common in the mechanical field, generally composed of multiple transmission rods joined end-to-end, much like human joints. They transmit power by bending, swinging, and extending through hinged pivots. This application does not describe their detailed structure here, and the accompanying drawings are only schematic diagrams. Therefore, using the piezoelectric ceramic drive motor 162 to drive the corresponding flexible hinge structure 163 can move the base 150 in both the horizontal and vertical directions (i.e., the attached drawings). Figure 2 (Horizontal and vertical movement within the text).

[0029] It should be noted that the detailed structure of the first moving mechanism 160 described above is only one embodiment for moving the base 150. The technical solution of this application can also employ any other first moving mechanism 160 capable of moving the base 150 in the horizontal direction.

[0030] In some embodiments of this application, the bonding system 100 further includes a second moving mechanism (not shown) for moving the upper wafer chuck 140; the control center is also used to control the second moving mechanism. Specifically, the second moving mechanism is used to move the upper wafer chuck 140 to align the lower wafer 131 and the upper wafer 141 and to bring the upper wafer 141 sufficiently close to the lower wafer 131 to initiate bonding. The second moving mechanism can be any device or structure well known to those skilled in the art for moving wafer chucks, such as a robotic arm.

[0031] In some embodiments of this application, the bonding system 100 further includes: a third moving mechanism (not shown) for controlling the vertical movement of the plunger 151 (e.g., telescopic movement in the vertical direction); the control center is also used to control the third moving mechanism. The plunger 151 is configured to move vertically. The detailed structure of the plunger 151 can be any structure capable of vertical movement known to those skilled in the art. For example, a portion of the plunger 151 can be embedded in the base 150, and the plunger 151 can extend and retract vertically based on the base 150. For example, the plunger 151 can be driven by the base 150 to move vertically.

[0032] In some embodiments of this application, the detection system 170 includes a plurality of lenses for capturing images and performing positioning based on the images. In some embodiments of this application, the method by which the detection system 170 detects the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140 includes: locating the center of the upper wafer chuck 140 and establishing a horizontal x-axis-y-axis planar coordinate system with the center of the upper wafer chuck 140 as the origin; locating the center of the upper wafer 141 and generating the coordinates (X, Y) of the center of the upper wafer 141 based on the planar coordinate system. Here, X represents the offset in the x-axis direction, and Y represents the offset in the y-axis direction.

[0033] In some embodiments of this application, the detection system 170 is also used to provide a position calibration function when aligning the upper wafer 141 and the lower wafer 131.

[0034] This application provides a wafer bonding system in which, before bonding, the positional offset between the center of the upper wafer and the center of the upper wafer chuck is detected by a detection system, and then the plunger is moved by a first moving mechanism to ensure that the plunger is located directly above the center of the upper wafer. This ensures that the bonding wave propagates symmetrically from the center of the wafer, thereby improving the quality of wafer bonding.

[0035] This application also provides a wafer bonding method, which can be applied to the wafer bonding system 100 described above, including: step S1: detecting the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140 by a detection system 170; step S2: controlling the plunger 151 in the through hole located at the center of the upper wafer chuck 140 to move horizontally according to the detection result, the plunger 151 is used to press down the upper wafer 141 to bond with the lower wafer 131. Specifically, for example, the detection result of the detection system 170 is received by a control center and the first moving mechanism 160 is controlled to move the base 150 according to the detection result.

[0036] In some embodiments of this application, the method of receiving the detection results of the detection system 170 through the control center and controlling the first moving mechanism 160 to control the base 150 to move according to the detection results includes: the control center controlling the first moving mechanism 160 to control the base 150 to move according to the positional offset between the center of the upper wafer 141 and the center of the upper wafer chuck 140, thereby causing the plunger 151 to move directly above the center of the upper wafer 141.

[0037] In some embodiments of this application, the bonding method further includes: step S3: controlling the second moving mechanism through the control center to move the upper wafer chuck 140 so that the upper wafer 141 and the lower wafer 131 on the lower wafer chuck 130 are aligned in the vertical direction.

[0038] In some embodiments of this application, the bonding method further includes: step S4: controlling the third moving mechanism through the control center to control the plunger 151 to move vertically and press down on the center of the upper wafer 141 so that the center of the upper wafer 141 is attached to the center of the lower wafer 131.

[0039] In some embodiments of this application, the sequence of steps in the wafer bonding method may be: step S1-step S2-step S3-step S4. Alternatively, the sequence of steps in the wafer bonding method may be: step S3-step S1-step S2-step S4.

[0040] This application provides a wafer bonding system and a wafer bonding method. Before bonding, the system detects the positional offset between the center of the upper wafer and the center of the upper wafer chuck. Then, the first moving mechanism moves the plunger to ensure that the plunger is directly above the center of the upper wafer. This ensures that the bonding wave propagates symmetrically from the center of the wafer, thereby improving the quality of wafer bonding.

[0041] In summary, after reading this application, those skilled in the art will understand that the foregoing content is presented by way of example only and is not restrictive. Although not explicitly stated herein, those skilled in the art will understand that this application is intended to encompass various reasonable changes, improvements, and modifications to the embodiments. These changes, improvements, and modifications are all within the spirit and scope of the exemplary embodiments of this application.

[0042] It should be understood that the term "and / or" as used in this embodiment includes any or all combinations of one or more of the associated listed items. It should be understood that when an element is referred to as "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element.

[0043] Similarly, it should be understood that when an element such as a layer, region, or substrate is referred to as being "on" another element, it may be directly on that other element, or there may be intermediate elements present. Conversely, the term "directly" means without intermediate elements. It should also be understood that the terms "comprising," "including," "containing," or "comprises," as used in this application, indicate the presence of the described features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof.

[0044] It should also be understood that although the terms first, second, third, etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Therefore, without departing from the teachings of this application, a first element in some embodiments may be referred to as a second element in other embodiments. The same reference numerals or the same reference signs denote the same elements throughout the specification.

[0045] Furthermore, this application specification describes exemplary embodiments by referring to idealized exemplary cross-sectional views and / or plan views and / or perspective views. Therefore, differences from the illustrated shapes are foreseeable due to factors such as manufacturing techniques and / or tolerances. Thus, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but should include deviations in shape caused, for example, by manufacturing processes. For instance, etched areas shown as rectangular typically have circular or curved features. Therefore, the regions shown in the figures are substantially schematic, and their shapes are not intended to illustrate the actual shape of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

Claims

1. A wafer bonding system, characterized in that, include: Chamber; A base is disposed within the chamber; A lower wafer chuck is supported on the base and is used to fix the lower wafer. An upper wafer chuck is disposed in the upper part of the chamber. The upper wafer chuck is used to fix the upper wafer. A through hole is provided in the center of the upper wafer chuck. A plunger, disposed in the through hole, is used to press down the upper wafer to bond it with the lower wafer; A first moving mechanism is configured to control the plunger to move horizontally in the through hole; A detection system is installed in the upper part of the chamber, and the detection system is used to detect the positional offset between the center of the upper wafer and the center of the upper wafer chuck; The control center is communicatively connected to the detection system and the first moving mechanism. The control center is used to receive the detection results of the detection system and control the first moving mechanism according to the detection results.

2. The wafer bonding system as described in claim 1, characterized in that, Also includes: A base is disposed above the upper wafer chuck, and a plunger is disposed on the base and extends into the through hole from below the base.

3. The wafer bonding system as described in claim 2, characterized in that, The first moving mechanism includes: a stator disposed on the upper surface of the upper wafer chuck and surrounding the base; four piezoelectric ceramic drive motors evenly disposed on the inner wall of the stator; and four flexible hinge structures respectively connecting each piezoelectric ceramic drive motor and the side wall of the base, wherein the piezoelectric ceramic drive motor is configured to drive the corresponding flexible hinge structure to move the base.

4. The wafer bonding system as described in claim 3, characterized in that, The method by which the control center receives the detection results of the detection system and controls the first moving mechanism according to the detection results includes: the control center controls the first moving mechanism to move the base and drive the plunger to move directly above the center of the upper wafer according to the positional offset between the upper wafer center and the upper wafer chuck center.

5. The wafer bonding system as described in claim 1, characterized in that, Also includes: The second moving mechanism is used to move the upper wafer chuck; the control center is also used to control the second moving mechanism.

6. The wafer bonding system as described in claim 1, characterized in that, Also includes: The third moving mechanism is used to control the piston to move in the vertical direction; the control center is also used to control the third moving mechanism.

7. The wafer bonding system as described in claim 1, characterized in that, The cross-sectional shape of the through hole can be circular or square.

8. The wafer bonding system as described in claim 7, characterized in that, The diameter of the through hole is 12 to 15 mm or the side length of the through hole is 12 to 15 mm.

9. A wafer bonding method, characterized in that, include: Detect the positional offset between the center of the upper wafer and the center of the upper wafer chuck; Based on the test results, the plunger located in the through hole at the center of the upper wafer chuck is controlled to move horizontally. The plunger is used to press down the upper wafer to bond it with the lower wafer.

10. The wafer bonding method as described in claim 9, characterized in that, The method for controlling the horizontal movement of the plunger in the through hole located at the center of the upper wafer chuck based on the detection results includes: controlling the plunger to move directly above the center of the upper wafer based on the positional offset between the center of the upper wafer and the center of the upper wafer chuck.

11. The wafer bonding method as described in claim 9, characterized in that, Also includes: Move the upper wafer chuck so that the lower wafer on the upper wafer chuck and the lower wafer chuck are aligned in the vertical direction.

12. The wafer bonding method as described in claim 9, characterized in that, Also includes: The plunger is controlled to move vertically and press down on the center of the upper wafer so that the center of the upper wafer is in contact with the center of the lower wafer.

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