Bonding alignment system, bonding device, and bonding method

Abstract

The present invention provides a bonding alignment system, a bonding device, and a bonding method. The bonding alignment system comprises: a first target, provided with a first target point to calibrate a first position of a wafer; a transparent second target, located between the first target and an image acquisition apparatus, and provided with a second target point to calibrate a second position of a member to be bonded; the image acquisition apparatus, used for acquiring, by means of an optical compensation assembly, a first image containing the first target point and a second image containing the second target point, so as to indicate an alignment deviation amount between the first position and the second position; and the optical compensation assembly, located between the second target and the image acquisition apparatus, and comprising a plurality of optical path regions.

Description

A bonding alignment system, bonding apparatus and bonding method Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and more particularly to a bonding alignment system, a bonding apparatus, and a bonding method. Background Technology

[0002] In the field of semiconductor manufacturing technology, bonding technology enables the three-dimensional integration of semiconductor devices. This means that by bonding two or more semiconductor structures with the same or different functions, chip performance can be improved. Here, bonding processes can be categorized according to the bonding object, including wafer-to-wafer (W2W) bonding, die-to-wafer (D2W) bonding, and die-to-die (D2D) bonding.

[0003] In the alignment step of the chip-to-wafer bonding process, the optical microscopy system needs to image the targets on both the chip and the wafer to calculate the alignment deviation. In existing technology, alignment is achieved by designing a glass target on the chip's carrier head. The glass target is located on the side of the same plane as the chip. After the positions of the glass target and the chip target are calibrated, the glass target can be aligned with the target directly opposite the wafer. However, because there is a certain vertical distance between the two targets, the depth of field of the microscope objective cannot cover this distance, and this distance varies depending on the chip thickness. When bonding different chips, a displacement microscope is needed to image the glass target and the wafer target. Therefore, the repeatability and accuracy errors introduced by this mechanical displacement will affect the bonding accuracy between the chip and the wafer.

[0004] To overcome the aforementioned deficiencies in the existing technology, this invention provides a bonding alignment technology that utilizes a simplified device structure to quickly calibrate the alignment deviation, thereby improving the efficiency of bonding alignment. Summary of the Invention

[0005] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed descriptions that follow.

[0006] To overcome the aforementioned deficiencies in the prior art, the present invention provides a bonding alignment system, a bonding device, and a bonding method, which utilize a simplified device structure to quickly calibrate the alignment deviation, thereby improving the efficiency of bonding alignment.

[0007] Specifically, the bonding alignment system provided according to a first aspect of the present invention includes: a first target having a first target point thereon to mark a first position of a wafer; a transparent second target located between the first target and an image acquisition device, having a second target point thereon to mark a second position of a component to be bonded; the image acquisition device being configured to acquire a first image with the first target point and a second image with the second target point via an optical compensation component to indicate an alignment deviation between the first position and the second position; and the optical compensation component being located between the second target and the image acquisition device and including a plurality of optical path length regions, wherein the optical compensation component moves its first optical path length region between the image acquisition device and the first target so that the image acquisition device can focus on the first target via the first optical path length region, and the optical compensation component further moves its second optical path length region between the image acquisition device and the second target so that the image acquisition device can focus on the second target via the second optical path length region.

[0008] Furthermore, in some embodiments of the present invention, the plurality of optical path zones are disposed on a turntable, and the optical compensation component switches between the first optical path zone and the second optical path zone by rotating the turntable.

[0009] Furthermore, in some embodiments of the present invention, the bonding alignment system further includes: a microscope objective, wherein the second optical path region is an empty region, the image acquisition device focuses the second target point via the microscope objective, and the first optical path region is provided with an optical path plate to compensate for the optical path difference between the first target and the second target, so that the image acquisition device can focus the first target point via the microscope objective, the optical path plate and the second target.

[0010] Furthermore, in some embodiments of the present invention, the optical path sheet is made of planar glass, and the relationship between its refractive index and thickness and the optical path difference is expressed as: l = dd / n, where l is the optical path difference, n is the refractive index of the optical path sheet, and d is the thickness of the optical path sheet.

[0011] Furthermore, in some embodiments of the present invention, the bonding alignment system is adapted to a variety of bonding components with different thicknesses, and the turntable is provided with a plurality of first optical path regions with corresponding first optical paths.

[0012] Furthermore, in some embodiments of the present invention, the second target point and the first surface of the component to be bonded near the image acquisition device both maintain a second optical path that is adapted to the second optical path region of the image acquisition device, and the first target point adapts to the position of the component to be bonded away from the second surface of the image acquisition device, while maintaining a corresponding first optical path with the image acquisition device. The optical compensation component is configured to: move the corresponding first optical path region between the image acquisition device and the first target according to the first optical path, so that the image acquisition device can focus on the first target through the first optical path region.

[0013] Furthermore, in some embodiments of the present invention, the thickness of the component to be bonded is between 30 micrometers and 800 micrometers, and the optical path sheet of the corresponding first optical path region is divided into multiple groups according to the refractive index, wherein each group of optical path sheets has a different refractive index, and each group of optical path sheets has the same refractive index and different thicknesses.

[0014] Furthermore, in some embodiments of the present invention, the first target is provided with a plurality of first target points, and the second target is provided with a plurality of corresponding second target points. The image acquisition device acquires a first image with a plurality of first target points and a second image with a plurality of corresponding second target points via the optical compensation component, so as to improve the detection accuracy of the alignment deviation of the first position and the second position.

[0015] Furthermore, the bonding apparatus provided according to a second aspect of the present invention includes: a bonding alignment system as described in any one of the first aspects of the present invention, for detecting an alignment deviation between a first position of a wafer to be bonded and a second position of a component to be bonded; a first bonding head having a first target of the bonding alignment system thereon for adsorbing the wafer; and a second bonding head having a second target of the bonding alignment system thereon for adsorbing the component to be bonded, and cooperating with the first bonding head to compensate for the alignment deviation, so as to bond the first position of the wafer to the second position of the component to be bonded.

[0016] Furthermore, the bonding method provided by the third aspect of the present invention includes the following steps: adsorbing a wafer to be bonded via a first bonding head of a bonding apparatus as described in the second aspect of the present invention, and adsorbing a workpiece to be bonded via a second bonding head thereon; moving a first optical path region of an optical compensation component of the bonding alignment system of the bonding apparatus between an image acquisition device and a first target of the first bonding head, so as to control the image acquisition device to focus on the first target via the first optical path region and acquire a first image with its first target point; moving a second optical path region of the optical compensation component between the image acquisition device and a second target of the second bonding head, so as to control the image acquisition device to focus on the second target via the second optical path region and acquire a second image with its second target point; determining an alignment deviation amount between the first position and the second position based on the positional difference between the first target point and the second target point in the corresponding image; and compensating for the alignment deviation amount via the first bonding head and / or the second bonding head, and bonding the first position of the wafer to the second position of the workpiece to be bonded. Attached Figure Description

[0017] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0018] Figure 1 shows a schematic diagram of the bonding alignment system provided according to some embodiments of the present invention.

[0019] Figure 2 shows a schematic diagram of the optical path principle for optical path sheet imaging according to some embodiments of the present invention.

[0020] Figure 3 shows the optical path diagram of optical path sheets of different thicknesses provided according to some embodiments of the present invention.

[0021] Figure 4 shows a schematic flowchart of a bonding method provided according to some embodiments of the present invention.

[0022] Figure reference numerals: 10 First target; 20 Second target; 201 Part to be bonded; 30 Microscope objective; 40 Optical path plate; 50 Turntable Detailed Implementation

[0023] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a thorough understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Furthermore, the terms "upper," "lower," "left," "right," "top," "bottom," "horizontal," and "vertical" used in the following description should be understood as the orientations shown in the relevant paragraphs and accompanying drawings. These relative terms are for illustrative purposes only and do not imply that the described apparatus must be manufactured or operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0026] It is understood that although terms such as "first," "second," and "third" may be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first components, regions, layers, and / or parts discussed below may be referred to as second components, regions, layers, and / or parts without departing from some embodiments of the present invention.

[0027] As mentioned above, in the field of semiconductor manufacturing technology, bonding technology can be used to achieve three-dimensional integration of semiconductor devices. That is, by bonding two or more semiconductor structures with the same or different functions, the performance of the chip can be improved. Here, bonding processes can be distinguished according to the bonding object, including wafer-to-wafer (W2W) bonding, die-to-wafer (D2W) bonding, and die-to-die (D2W) bonding.

[0028] In the alignment step of the chip-to-wafer bonding process, the optical microscopy system needs to image the targets on both the chip and the wafer to calculate the alignment deviation. In existing technology, alignment is achieved by designing a glass target on the chip's carrier head. The glass target is located on the side of the same plane as the chip. After the positions of the glass target and the chip target are calibrated, the glass target can be aligned with the target directly opposite the wafer. However, because there is a certain vertical distance between the two targets, the depth of field of the microscope objective cannot cover this distance, and this distance varies depending on the chip thickness. When bonding different chips, a displacement microscope is needed to image the glass target and the wafer target. Therefore, the repeatability and accuracy errors introduced by this mechanical displacement will affect the bonding accuracy between the chip and the wafer.

[0029] To overcome the aforementioned deficiencies in the prior art, the present invention provides a bonding alignment system, a bonding device, and a bonding method, which utilize a simplified device structure to quickly calibrate the alignment deviation, thereby improving the efficiency of bonding alignment.

[0030] In some non-limiting embodiments, the bonding alignment system provided in the first aspect of the present invention can be configured on the bonding device provided in the second aspect of the present invention, and the bonding method provided in the third aspect of the present invention can be implemented based on the bonding device provided in the second aspect of the present invention.

[0031] Specifically, the bonding apparatus provided according to a second aspect of the present invention includes a bonding alignment system, a first bonding head, and a second bonding head.

[0032] This bonding alignment system is used to detect the alignment deviation between a first position of the wafer to be bonded and a second position of the component to be bonded. The first bonding head is equipped with a first target of the bonding alignment system for adsorbing the wafer. The second bonding head is equipped with a second target of the bonding alignment system for adsorbing the component to be bonded, and works in conjunction with the first bonding head to compensate for the alignment deviation, thereby bonding the first position of the wafer to the second position of the component to be bonded.

[0033] Please refer to Figure 1, which shows a schematic diagram of the bonding alignment system provided according to some embodiments of the present invention.

[0034] As shown in Figure 1, the bonding alignment system includes a first target 10, a transparent second target 20 (e.g., made of glass), an image acquisition device, and an optical compensation component.

[0035] The first target 10 has a first target point to mark a first position on the wafer. A transparent second target 20 is located between the first target 10 and the image acquisition device, and has a second target point to mark a second position on the component 201 to be bonded. The image acquisition device is used to acquire a first image with the first target point and a second image with the second target point via an optical compensation assembly to indicate the alignment deviation between the first and second positions. The optical compensation assembly is located between the second target 20 and the image acquisition device and includes multiple optical path lengths. The optical compensation assembly moves its first optical path length between the image acquisition device and the first target 10 so that the image acquisition device can focus on the first target 10 via the first optical path length. The optical compensation assembly also moves its second optical path length between the image acquisition device and the second target 20 so that the image acquisition device can focus on the second target 20 via the second optical path length.

[0036] In some embodiments, multiple optical path zones are provided on a turntable 50, and the optical compensation component switches between the first optical path zone and the second optical path zone by rotating the turntable 50.

[0037] In some embodiments, the bonding alignment system further includes a microscope objective 30. The second optical path region is an empty region, and the image acquisition device focuses on the second target point via the microscope objective 30. The first optical path region is provided with an optical path plate 40 to compensate for the optical path difference between the first target 10 and the second target 20, so that the image acquisition device can focus on the first target point via the microscope objective 30, the optical path plate 40 and the second target 20.

[0038] Please refer to Figures 2 and 3. Figure 2 shows a schematic diagram of the optical path principle for imaging with an optical path sheet according to some embodiments of the present invention. Figure 3 shows a schematic diagram of the optical path principle for optical path sheets of different thicknesses according to some embodiments of the present invention.

[0039] As shown in Figure 2, the optical path difference plate 40 is made of flat glass to avoid optical errors such as spherical aberration, chromatic aberration, and coma introduced by the curvature lens. The relationship between the refractive index and thickness of this flat glass and the optical path difference is expressed as:

[0040] l = dd / n,

[0041] Where l is the optical path difference, n is the refractive index of the optical path plate 40, and d is the thickness of the optical path plate 40.

[0042] As shown in Figure 3, the bonding alignment system is adapted to various bonding components 201 with different thicknesses, and the turntable 50 is provided with multiple first optical path zones with corresponding first optical paths.

[0043] The second target point and the bonding component 201 are close to the first surface of the image acquisition device, and both maintain a second optical path that is adapted to the second optical path region of the image acquisition device. The first target point is adapted to the position of the bonding component 201 away from the second surface of the image acquisition device, and maintains a corresponding first optical path with the image acquisition device. The optical compensation component is configured to move the corresponding first optical path region between the image acquisition device and the first target 10 according to the first optical path, so that the image acquisition device can focus on the first target 10 through the first optical path region.

[0044] In some embodiments, the thickness of the component to be bonded 201 is between 30 micrometers and 800 micrometers, and the optical path sheets 40 of the corresponding first optical path region are divided into multiple groups according to their refractive index. Each group of optical path sheets 40 has a different refractive index, while each group of optical path sheets 40 has the same refractive index and a different thickness to accommodate a wide thickness range. Specifically, this grouping method can, on the one hand, prevent excessively thick optical path sheets 40 from absorbing too much light energy and affecting image quality, and on the other hand, balance the weight differences at various positions of the turntable 50 to avoid alignment errors caused by the tilt of the turntable 50.

[0045] In some embodiments, variations in the thickness of the component to be bonded 201 will correspondingly cause an optical path difference in the focus drift of the microscope objective 30. For example, for a component to be bonded 201 with a first thickness t1 (e.g., 40 μm), an optical path sheet 40 with a first refractive index n1 (e.g., 1.52) and a first thickness d1 (e.g., 117 μm) can be used. For a chip with a second thickness t2 (e.g., 600 μm), an optical path sheet 40 with a second refractive index n2 (e.g., 1.51) and a second thickness d2 (e.g., 1776 μm) can be used.

[0046] In some embodiments, the first target 10 is provided with a plurality of first target points, and the second target 20 is provided with a plurality of corresponding second target points. The image acquisition device acquires a first image with a plurality of first target points and a second image with a plurality of corresponding second target points via an optical compensation component, so as to improve the detection accuracy of the alignment deviation of the first position and the second position.

[0047] The working principle of the above-described bonding alignment system and bonding apparatus will be described below with reference to some embodiments of bonding methods. Those skilled in the art will understand that these embodiments of bonding methods are merely non-limiting implementations provided by the present invention, intended to clearly demonstrate the main concepts of the invention and provide specific solutions convenient for public implementation, rather than limiting all functions or operating modes of the bonding alignment system and bonding apparatus. Similarly, the bonding alignment system and bonding apparatus system are also merely non-limiting implementations provided by the present invention, and do not constitute a limitation on the executing entity or execution order of the steps in these bonding methods.

[0048] Please refer to Figure 4, which shows a schematic flowchart of a bonding method provided according to some embodiments of the present invention.

[0049] As shown in Figure 4, the bonding method first adsorbs the wafer to be bonded via the first bonding head of the bonding equipment, and then adsorbs the workpiece 201 to be bonded via its second bonding head.

[0050] The first optical path zone of the optical compensation component of the bonding alignment system of the bonding device is moved between the image acquisition device and the first target 10 of the first bonding head, so as to control the image acquisition device to focus on the first target 10 through the first optical path zone and acquire a first image with its first target point.

[0051] The second optical path zone of the optical compensation component is moved between the image acquisition device and the second target 20 of the second bonding head to control the image acquisition device to focus on the second target 20 via the second optical path zone and acquire a second image with its second target point.

[0052] Based on the positional difference between the first target point and the second target point in the corresponding image, determine the alignment deviation between the first and second positions; and

[0053] The alignment deviation is compensated by the first bonding head and / or the second bonding head, and the first position of the wafer is bonded to the second position of the workpiece 201 to be bonded.

[0054] In summary, the bonding alignment system, bonding device, and bonding method provided by this invention can quickly calibrate the alignment deviation using a simplified device structure, thereby improving the efficiency of bonding alignment.

[0055] Although the methods described above are illustrated and depicted as a series of actions for the sake of simplicity, it should be understood and appreciated that these methods are not limited by the order of the actions, as some actions may occur in a different order and / or concurrently with other actions from the illustrations and descriptions herein or not illustrated and described herein but which may be understood by those skilled in the art, according to one or more embodiments.

[0056] The prior description of this disclosure is provided to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A bonding alignment system, characterized in that, include: The first target has a first target point on it to mark the first position of the wafer; A transparent second target is located between the first target and the image acquisition device, and a second target point is provided on it to mark the second position of the component to be bonded. The image acquisition device is used to acquire a first image with the first target point and a second image with the second target point via an optical compensation component, so as to indicate the alignment deviation between the first position and the second position. as well as The optical compensation component is located between the second target and the image acquisition device, and includes multiple optical path regions. The optical compensation component moves its first optical path region between the image acquisition device and the first target so that the image acquisition device can focus on the first target via the first optical path region. The optical compensation component also moves its second optical path region between the image acquisition device and the second target so that the image acquisition device can focus on the second target via the second optical path region.

2. The bonding alignment system as described in claim 1, characterized in that, The plurality of optical path zones are set on a turntable, and the optical compensation component switches between the first optical path zone and the second optical path zone by rotating the turntable.

3. The bonding alignment system as described in claim 2, characterized in that, Also includes: A microscope objective, wherein the second optical path region is an empty region, the image acquisition device focuses the second target point through the microscope objective, and the first optical path region is provided with an optical path plate to compensate for the optical path difference between the first target and the second target, so that the image acquisition device can focus the first target point through the microscope objective, the optical path plate and the second target.

4. The bonding alignment system as described in claim 3, characterized in that, The optical path plate is made of flat glass, and the relationship between its refractive index and thickness and the optical path difference is expressed as: l = dd / n. Wherein, l is the optical path difference, n is the refractive index of the optical path plate, and d is the thickness of the optical path plate.

5. The bonding alignment system as described in claim 4, characterized in that, The bonding alignment system is compatible with various bonding components of different thicknesses, and the turntable is provided with multiple first optical path zones with corresponding first optical paths.

6. The bonding alignment system as described in claim 5, characterized in that, The second target point and the first surface of the component to be bonded, which is close to the image acquisition device, both maintain a second optical path length that is adapted to the second optical path region of the image acquisition device. The first target point adapts to the position of the component to be bonded away from the second surface of the image acquisition device, while maintaining a corresponding first optical path length with the image acquisition device. The optical compensation component is configured as follows: According to the first optical path, the corresponding first optical path region is moved between the image acquisition device and the first target, so that the image acquisition device can focus on the first target via the first optical path region.

7. The bonding alignment system as described in claim 5, characterized in that, The thickness of the component to be bonded is between 30 micrometers and 800 micrometers. The optical path sheets of the corresponding first optical path region are divided into multiple groups according to the refractive index. Each group of optical path sheets has a different refractive index, and each group of optical path sheets has the same refractive index and different thicknesses.

8. The bonding alignment system as described in claim 1, characterized in that, The first target has multiple first target points, and the second target has multiple corresponding second target points. The image acquisition device acquires a first image with multiple first target points and a second image with multiple corresponding second target points via the optical compensation component, so as to improve the detection accuracy of the alignment deviation of the first position and the second position.

9. A bonding apparatus, characterized in that, include: The bonding alignment system according to any one of claims 1 to 8 is used to detect the alignment deviation between a first position of the wafer to be bonded and a second position of the workpiece to be bonded; The first bonding head is provided with a first target of the bonding alignment system for adsorbing the wafer; as well as The second bonding head is provided with a second target of the bonding alignment system for adsorbing the workpiece to be bonded and cooperating with the first bonding head to compensate for the alignment deviation, so as to bond the first position of the wafer to the second position of the workpiece to be bonded.

10. A bonding method, characterized in that, Includes the following steps: The wafer to be bonded is adsorbed via the first bonding head of the bonding apparatus as described in claim 9, and the workpiece to be bonded is adsorbed via its second bonding head; The first optical path zone of the optical compensation component of the bonding alignment system of the bonding device is moved between the image acquisition device and the first target of the first bonding head, so as to control the image acquisition device to focus on the first target through the first optical path zone and acquire a first image with its first target point. The second optical path zone of the optical compensation component is moved between the image acquisition device and the second target of the second bonding head to control the image acquisition device to focus on the second target via the second optical path zone and acquire a second image with its second target point. Based on the positional difference between the first target point and the second target point in the corresponding image, the alignment deviation between the first position and the second position is determined; as well as The alignment deviation is compensated via the first bonding head and / or the second bonding head, and the first position of the wafer is bonded to the second position of the workpiece to be bonded.

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