Wafer alignment device

Abstract

The utility model provides a kind of wafer alignment device, it is related to the technical field of semiconductor processing, to solve the problem that existing optical alignment device needs to carry out objective switching when aligning wafer, resulting in the existence of mechanical error and positioning deviation is designed.The optical alignment device includes microscopic objective, first camera, second camera and light source, the first end of microscopic objective is towards wafer, and the side of wafer towards microscopic objective is provided with alignment mark;First camera is aligned the second end of microscopic objective through first tube lens module and light splitting module;Second camera is aligned the second end of microscopic objective through second tube lens module and light splitting module, second tube lens module and first tube lens module have different magnification;Light source is used for illuminating wafer and alignment mark.The utility model can realize fast wide-range search and high-precision positioning synchronous completion, without mechanical switching, avoid the existence of mechanical error and positioning deviation.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor processing technology, and more specifically, to a wafer alignment device. Background Technology

[0002] In the field of semiconductor processing technology, the wafer-to-chip bonding process is crucial. Before bonding, the wafer and chip must be aligned. Currently, wafer-to-chip alignment is often achieved using an objective lens turret. Specifically, multiple objectives (usually 5-6) are mounted on an electrically controlled turret, and switching between high and low magnification objectives is achieved by rotating the turret. The low-magnification objective is used for searching first, followed by the high-magnification objective for precise positioning, thus combining searching and positioning. However, using an objective lens turret occupies a significant amount of space, is prone to interference with adjacent components during rotation, and switching objectives via turret rotation is inefficient.

[0003] To reduce space requirements, the objective turret can be modified into a dual-objective switching mechanism, that is, switching only between the high-magnification and low-magnification objectives, which can reduce size while improving switching efficiency. However, this dual-objective switching mechanism has mechanical errors and positioning deviations, making it difficult to guarantee image quality. Utility Model Content

[0004] The purpose of this invention is to provide a wafer alignment device to solve the technical problem that existing wafer alignment devices require objective lens switching during wafer alignment, resulting in mechanical errors and positioning deviations.

[0005] The wafer alignment device provided by this utility model includes:

[0006] A microscope objective, the first end of which faces the wafer, and an alignment mark is provided on the side of the wafer facing the microscope objective;

[0007] The first camera is aligned with the second end of the microscope objective via the first tube lens module and the beam splitter module;

[0008] A second camera, aligned with the second end of the microscope objective via a second endoscope module and the beam-splitting module, wherein the second endoscope module has a different magnification than the first endoscope module; and

[0009] A light source is used to illuminate the wafer and the alignment marks.

[0010] Furthermore, the beam splitting module includes a first semi-reflective lens, which forms an angle with the light rays emitted from the second end of the microscope objective.

[0011] Furthermore, the beam splitting module also includes a first reflector, which is located between the first half-reflective lens and the second tube mirror module. The first reflector is used to reflect the light reflected by the first half-reflective lens to the second tube mirror module.

[0012] Furthermore, the second tube endoscope module includes a first mirror group, a second reflecting mirror, and a second mirror group. The second reflecting mirror is located between the first mirror group and the second mirror group, and is used to reflect the light from the first mirror group to the second mirror group.

[0013] Furthermore, the wafer alignment device also includes a second semi-reflective lens, which is located between the second end of the microscope objective and the beam splitter module. The light source is aligned with the second end of the microscope objective via the second semi-reflective lens. The second semi-reflective lens forms an angle with the light emitted from the second end of the microscope objective.

[0014] Furthermore, the wafer alignment device also includes an illumination module located between the light source and the second semi-reflective lens. The illumination module is used to collimate, homogenize, and expand the light emitted by the light source.

[0015] Furthermore, the wafer alignment device also includes a longitudinal movement mechanism, on which the microscope objective is mounted, and the longitudinal movement mechanism is used to drive the microscope objective to move closer to or further away from the wafer along the Z direction.

[0016] Furthermore, the wafer alignment apparatus also includes a motion stage on which the wafer is supported, the motion stage being configured to give the wafer a degree of freedom of movement along the X and Y directions and a degree of freedom of rotation about the Z direction.

[0017] Furthermore, the wavelength of the light emitted by the light source is between 400 and 1500 nm.

[0018] Furthermore, the magnification of the second endoscope module is twice that of the first endoscope module.

[0019] The beneficial effects of this wafer alignment device are:

[0020] When in use, the light source illuminates the wafer and alignment marks. The reflected light from the alignment marks passes through the microscope objective and reaches the beam splitter. Part of the light, after passing through the beam splitter, is imaged onto the first camera via the first tube lens module, and the other part of the light, after passing through the beam splitter, is imaged onto the second camera via the second tube lens module.

[0021] By setting the second lens module and the first lens module to have different magnifications, for example, setting the magnification of the second lens module to be greater than that of the first lens module, the wafer alignment device can perform coarse alignment using the first camera to make the alignment mark clearly imaged in the field of view of the first camera, and perform fine alignment using the second camera to make the alignment mark clearly imaged in the field of view of the second camera, thus completing the alignment process.

[0022] This wafer alignment device uses a dual-lens, dual-camera, and shared objective lens design. By utilizing the different magnifications of different lens modules, it achieves rapid, wide-range searching and high-precision positioning simultaneously without the need for mechanical switching. This avoids mechanical errors and positioning deviations, thus ensuring image quality. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the wafer alignment device provided in Embodiment 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the wafer alignment device provided in Embodiment 2 of this utility model;

[0026] Figure 3 This is a schematic diagram of the wafer alignment device provided in Embodiment 3 of the present invention;

[0027] Figure 4 Schematic diagram of the alignment principle of the wafer alignment device provided in various embodiments of this utility model Figure 1 ;

[0028] Figure 5 Schematic diagram of the alignment principle of the wafer alignment device provided in various embodiments of this utility model Figure 2 .

[0029] Explanation of reference numerals in the attached figures:

[0030] 010 - Wafer; 020 - Alignment mark;

[0031] 100 - Microscope objective; 210 - First camera; 220 - First tube mirror module; 300 - Beam splitter module; 310 - First semi-reflective lens; 320 - First reflecting mirror; 410 - Second camera; 420 - Second tube mirror module; 421 - First mirror group; 422 - Second reflecting mirror; 423 - Second mirror group; 500 - Second semi-reflective lens; 600 - Illumination module; 700 - Longitudinal movement mechanism; 800 - Movement stage; 900 - Light source. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit it.

[0033] Example 1

[0034] Figure 1 This is a schematic diagram of the wafer alignment device provided in Embodiment 1. Figure 1 As shown, this embodiment provides a wafer alignment device, including a microscope objective 100, a first camera 210, a second camera 410, and a light source 900. Specifically, the first end of the microscope objective 100 faces the wafer 010, and an alignment mark 020 is provided on the side of the wafer 010 facing the microscope objective 100. The first camera 210 is aligned with the second end of the microscope objective 100 via a first tube mirror module 220 and a beam splitter module 300. The second camera 410 is aligned with the second end of the microscope objective 100 via a second tube mirror module 420 and a beam splitter module 300, wherein the second tube mirror module 420 and the first tube mirror module 220 have different magnifications. The light source 900 is used to illuminate the wafer 010 and the alignment mark 020.

[0035] When the wafer alignment device is in use, the light source 900 illuminates the wafer 010 and the alignment mark 020; the reflected light from the alignment mark 020 passes through the microscope objective 100 and reaches the beam splitting module 300. Part of the light, after passing through the beam splitting module 300, is imaged onto the first camera 210 via the first tube lens module 220, and the other part of the light, after passing through the beam splitting module 300, is imaged onto the second camera 410 via the second tube lens module 420.

[0036] By setting the second lens module 420 and the first lens module 220 to have different magnifications, for example, setting the magnification of the second lens module 420 to be greater than that of the first lens module 220, the wafer alignment device can perform coarse alignment using the first camera 210 to clearly image the alignment mark 020 within the field of view of the first camera 210, and perform fine alignment using the second camera 410 to clearly image the alignment mark 020 within the field of view of the second camera 410, thus completing the alignment process.

[0037] This wafer alignment device uses a dual-lens, dual-camera, and shared objective lens design. By utilizing the different magnifications of different lens modules, it achieves rapid, wide-range searching and high-precision positioning simultaneously without the need for mechanical switching. This avoids mechanical errors and positioning deviations, thus ensuring image quality.

[0038] It should be noted that the first endoscope module 220 can clearly image the object magnified by the microscope objective 100 onto the sensor of the first camera 210 at a certain magnification. The first camera 210 can convert the incident light signal on its sensor into an electrical signal and output the electrical signal to the corresponding signal processing system. The second endoscope module 420 can clearly image the object magnified by the microscope objective 100 onto the sensor of the second camera 410 at another magnification. The second camera 410 can convert the incident light signal on its sensor into an electrical signal and output the electrical signal to the corresponding signal processing system.

[0039] Please continue to refer to Figure 1 In this embodiment, the beam splitting module 300 may include a first semi-reflective lens 310, wherein the first semi-reflective lens 310 forms an angle with the light emitted from the second end of the microscope objective 100.

[0040] With this configuration, 50% of the light emitted from the second end of the microscope objective 100 is transmitted through the first semi-reflective lens 310 and received by the first camera 210, while the other 50% of the light emitted from the second end of the microscope objective 100 is reflected by the first semi-reflective lens 310 and received by the second camera 410.

[0041] In this embodiment, the first semi-reflective lens 310 forms a 45° angle with the light rays emitted from the second end of the microscope objective 100.

[0042] Please continue to refer to Figure 1 In this embodiment, the wafer alignment device may further include a second semi-reflective lens 500. Specifically, the second semi-reflective lens 500 is located between the second end of the microscope objective 100 and the beam splitter 300, and the light source 900 is aligned with the second end of the microscope objective 100 through the second semi-reflective lens 500. The second semi-reflective lens 500 forms an angle with the light emitted through the second end of the microscope objective 100.

[0043] With this configuration, the light emitted by the light source 900 can be reflected by the second semi-reflective lens 500 to the second end of the microscope objective 100, and further illuminate the wafer 010 and the alignment mark 020 on the surface of the wafer 010 through the microscope objective 100. The light reflected by the alignment mark 020 will return along the original path, be magnified by the microscope objective 100, and then pass through the second semi-reflective lens 500. After that, 50% of the light reaches the first camera 210 after being transmitted through the first semi-reflective lens 310, and the other 50% of the light reaches the second camera 410 after being reflected by the first semi-reflective lens 310.

[0044] The second semi-reflective lens 500 allows the light source 900 to be positioned laterally in the optical path between the microscope objective 100 and the beam splitter 300, thereby reducing the space occupied in the height direction.

[0045] In this embodiment, the second semi-reflective lens 500 forms a 45° angle with the light rays emitted from the second end of the microscope objective lens 100.

[0046] Please continue to refer to Figure 1 In this embodiment, the wafer alignment device may further include an illumination module 600. Specifically, the illumination module 600 is located between the light source 900 and the second half-reflective lens 500. The illumination module 600 is used to collimate, homogenize, and expand the light emitted by the light source 900.

[0047] By setting up the lighting module 600, it is possible to collimate, homogenize, and expand the light emitted by the light source 900, so that the light emitted by the light source 900 can smoothly reach the second half-reflective lens 500.

[0048] Please continue to refer to Figure 1 In this embodiment, the wafer alignment device may further include a longitudinal moving mechanism 700, wherein the microscope objective 100 is mounted on the longitudinal moving mechanism 700, and the longitudinal moving mechanism 700 is used to drive the microscope objective 100 to move closer to or away from the wafer 010 along the Z direction.

[0049] The aforementioned longitudinal movement mechanism 700 enables precise longitudinal displacement of the microscope objective 100 mounted thereon, so that the focal plane of the microscope objective 100 coincides with the plane where the alignment mark 020 is located.

[0050] Specifically, the longitudinal movement mechanism 700 can be an electric push rod.

[0051] Please continue to refer to Figure 1In this embodiment, the wafer alignment device may further include a motion stage 800, wherein the wafer 010 is supported on the motion stage 800, and the motion stage 800 is configured to give the wafer 010 a degree of freedom of movement along the X and Y directions and a degree of freedom of rotation about the Z direction.

[0052] Using the motion stage 800, the wafer 010 can be moved along the X and Y directions and rotated around the Z direction, thereby adjusting the horizontal position and the deflection position around the Z direction of the wafer 010 to achieve the alignment operation of the wafer 010.

[0053] In this embodiment, the wavelength of the light emitted by the light source 900 is between 400 and 1500 nm.

[0054] This setting allows the light emitted by the light source 900 to cover visible light, part of ultraviolet light, and part of infrared light, resulting in a wide spectral range.

[0055] In this embodiment, the magnification of the second endoscope module 420 is twice that of the first endoscope module 220.

[0056] Specifically, in this embodiment, the magnification of the microscope objective 100 is 20x, the magnification of the first tube mirror module 220 is 0.5x, and the magnification of the second tube mirror module 420 is 1x. Based on the formula: Overall magnification = Microscope objective 100 magnification × Tube mirror module magnification, it can be concluded that the image imaged on the first camera 210 is a 10x magnified object, and the image imaged on the second camera 410 is a 20x magnified object.

[0057] This setting allows the first camera 210 to maintain search efficiency for alignment mark 020 by magnifying the object at a lower magnification, while the second camera 410 can maintain positioning accuracy for alignment mark 020 by magnifying the object at a higher magnification.

[0058] Example 2

[0059] This embodiment provides another wafer alignment device, which differs from the wafer alignment device provided in Embodiment 1 as described below.

[0060] Figure 2 This is a schematic diagram of the wafer alignment device provided in Embodiment 2. Figure 2 As shown, the beam splitting module 300 may also include a first reflector 320. Specifically, the first reflector 320 is located between the first half-reflecting lens 310 and the second tube mirror module 420. The first reflector 320 is used to reflect the light reflected by the first half-reflecting lens 310 to the second tube mirror module 420.

[0061] By setting a first reflector 320 between the first semi-reflective lens 310 and the second tube mirror module 420, the light reflected back by the first semi-reflective lens 310 can be reflected by the first reflector 320 to the second tube mirror module 420, so that the second tube mirror module 420 can be placed vertically like the first tube mirror module 220, effectively saving horizontal space.

[0062] Example 3

[0063] This embodiment provides another wafer alignment device, which differs from the wafer alignment device provided in Embodiment 1 above in the following aspects.

[0064] Figure 3 This is a schematic diagram of the wafer alignment device provided in Embodiment 3. Figure 3 As shown, the second telescope module 420 includes a first mirror group 421, a second reflector 422, and a second mirror group 423. The second reflector 422 is located between the first mirror group 421 and the second mirror group 423, and is used to reflect the light from the first mirror group 421 to the second mirror group 423.

[0065] In this embodiment, the second tube mirror module 420 is decomposed into a first mirror group 421, a second reflecting mirror 422, and a second mirror group 423. The first mirror group 421 and the second mirror group 423 are used to magnify the object by a certain magnification. The second reflecting mirror 422 is used to change the angle of the light emitted from the first mirror group 421 so that the light emitted horizontally can be received by the vertically set second mirror group 423.

[0066] In all the above embodiments, the alignment principle of wafer 010 is the same. The alignment principle of wafer 010 will be described in detail below.

[0067] When alignment of wafer 010 is required, a robotic arm can be used to place wafer 010 on the motion stage 800, positioning wafer 010 at the alignment station. Two sets of wafer alignment devices are set up, wherein the wafer alignment devices are the wafer alignment devices in any of the embodiments one to three. Wafer 010 is provided with two alignment marks 020, one alignment mark 020 located in the left area of ​​wafer 010 and the other alignment mark 020 located in the right area of ​​wafer 010. The loading accuracy of the robotic arm can ensure that the alignment marks 020 on both sides appear within the field of view of the first camera 210 of the left and right wafer alignment devices, respectively.

[0068] The light sources 900 of the left and right sets of wafer alignment devices are turned on respectively, and the longitudinal position of the microscope objective 100 is adjusted by their respective longitudinal movement mechanisms 700, so that the alignment marks 020 on the left and right sides are clearly imaged within the fields of view of the two first cameras 210.Figure 4 Schematic diagram of the alignment principle of the wafer alignment apparatus provided in these embodiments Figure 1 ,like Figure 4 As shown, the first cameras 210 of the two sets of wafer alignment devices convert the optical images of the alignment mark 020 on the left and the alignment mark 020 on the right into electrical signals and provide them to the signal processing system. The signal processing system records that the coordinates (Xl1, Yl1) of the alignment mark 020 captured by the left wafer alignment device in the coordinate system of the first camera 210 are subtracted from the coordinates (Xcl1, Ycl1) of the field of view center of the first camera 210 of the left wafer alignment device, and the coordinates (Xr1, Yr1) of the alignment mark 020 captured by the right wafer alignment device in the coordinate system of the first camera 210 are... Subtracting the field-of-view center coordinates (Xcr1, Ycr1) of the first camera 210 of the wafer alignment device on the right, we get ΔXl1=Xcl1-Xl1, ΔYl1=Ycl1-Yl1, ΔXr1=Xcr1-Xr1, ΔYr1=Ycr1-Yr1. Further calculations yield the required horizontal movement distance ΔX1=(ΔXl1+ΔXr1) / 2, ΔY1=(ΔYl1+ΔYr1) / 2, and the required rotation angle Δθ1=arctan((Yl1-Yr1) / (Xr1-Xl1)).

[0069] Based on the above calculation data, the wafer 010 can be driven by the motion stage 800 to translate ΔX1 and ΔY1 in the plane and then rotate Δθ1 so that the alignment marks 020 on the left and right sides appear as close as possible to the center of the field of view of the first camera 210, thus completing the coarse alignment of the wafer 010.

[0070] The two sets of second cameras 410 convert the optical images of the left alignment mark 020 and the right alignment mark 020 into electrical signals and provide them to the signal processing system. Figure 5 Schematic diagram of the alignment principle of the wafer alignment apparatus provided in these embodiments Figure 2 ,like Figure 5As shown, the coordinates (Xl2, Yl2) of the alignment mark 020 captured by the left wafer alignment device in the coordinate system of its second camera 410 are subtracted from the field-of-view center coordinates (Xcl2, Ycl2) of the second camera 410 of the left wafer alignment device by the signal processing system. Similarly, the coordinates (Xr2, Yr2) of the alignment mark 020 captured by the right wafer alignment device in the coordinate system of its second camera 410 are subtracted from the field-of-view center coordinates (Xcr2, Yr2) of the second camera 410 of the right wafer alignment device. Subtracting Ycr2, we get ΔXl2=Xcl2-Xl2, ΔYl2=Ycl2-Yl2, ΔXr2=Xcr2-Xr2, ΔYr2=Ycr2-Yr2. Further calculations yield the required horizontal movement distance ΔX2=(ΔXl2+ΔXr2) / 2, ΔY2=(ΔYl2+ΔYr2) / 2 for wafer 010, and the required rotation angle Δθ2=arctan((Yl2-Yr2) / (Xr2-Xl2)).

[0071] Based on the above calculation data, the wafer 010 can be moved by the motion stage 800 to translate ΔX2 and ΔY2 in the plane and then rotate Δθ2 so that the alignment marks 020 on the left and right sides appear as close as possible to the center of the field of view of the second camera 410, thus completing the fine alignment of the wafer 010.

[0072] This completes the alignment operation for wafer 010.

[0073] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

[0074] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0075] In the above embodiments, descriptions of directions such as "up", "down", and "side" are based on the accompanying drawings.

[0076] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wafer alignment apparatus, characterized in that, include: A microscope objective (100) has its first end facing a wafer (010), and an alignment mark (020) is provided on the side of the wafer (010) facing the microscope objective (100); The first camera (210) is aligned with the second end of the microscope objective (100) via the first tube end module (220) and the beam splitter module (300); The second camera (410) is aligned with the second end of the microscope objective (100) via the second lens module (420) and the beam splitter module (300). The second lens module (420) has a different magnification than the first lens module (220). A light source (900) is used to illuminate the wafer (010) and the alignment mark (020).

2. The wafer alignment apparatus according to claim 1, characterized in that, The beam splitter module (300) includes a first semi-reflective lens (310), which forms an angle with the light emitted from the second end of the microscope objective (100).

3. The wafer alignment apparatus according to claim 2, characterized in that, The beam splitting module (300) further includes a first reflector (320), which is located between the first semi-reflective lens (310) and the second tube mirror module (420). The first reflector (320) is used to reflect the light reflected by the first semi-reflective lens (310) to the second tube mirror module (420).

4. The wafer alignment apparatus according to claim 2, characterized in that, The second tube mirror module (420) includes a first mirror group (421), a second reflector (422), and a second mirror group (423). The second reflector (422) is located between the first mirror group (421) and the second mirror group (423), and is used to reflect the light from the first mirror group (421) to the second mirror group (423).

5. The wafer alignment apparatus according to any one of claims 1-4, characterized in that, The wafer alignment device further includes a second semi-reflective lens (500), which is located between the second end of the microscope objective (100) and the beam splitter (300). The light source (900) is aligned with the second end of the microscope objective (100) through the second semi-reflective lens (500). The second semi-reflective lens (500) forms an angle with the light emitted from the second end of the microscope objective (100).

6. The wafer alignment apparatus according to claim 5, characterized in that, The wafer alignment device further includes an illumination module (600), which is located between the light source (900) and the second semi-reflective lens (500). The illumination module (600) is used to collimate, homogenize, and expand the light emitted by the light source (900).

7. The wafer alignment apparatus according to any one of claims 1-4, characterized in that, The wafer alignment apparatus further includes a longitudinal moving mechanism (700), on which the microscope objective (100) is mounted. The longitudinal moving mechanism (700) is used to drive the microscope objective (100) to move closer to or further away from the wafer (010) along the Z direction.

8. The wafer alignment apparatus according to any one of claims 1-4, characterized in that, The wafer alignment apparatus further includes a motion stage (800) on which the wafer (010) is supported. The motion stage (800) is configured to give the wafer (010) a degree of freedom of movement along the X and Y directions and a degree of freedom of rotation about the Z direction.

9. The wafer alignment apparatus according to any one of claims 1-4, characterized in that, The wavelength of light emitted by the light source (900) is between 400 and 1500 nm.

10. The wafer alignment apparatus according to any one of claims 1-4, characterized in that, The magnification of the second endoscope module (420) is twice that of the first endoscope module (220).

Images