Optical calibration imaging system and optical calibration method
By setting up an error detection unit in the optical calibration imaging system, the actual offset of the optical device is calculated and error compensation is performed, which solves the problem of decreased alignment accuracy during wafer bonding and achieves higher alignment accuracy.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SABERS CO LTD
- Filing Date
- 2026-01-14
- Publication Date
- 2026-07-23
AI Technical Summary
During wafer bonding, the alignment accuracy of the upper and lower imaging systems decreases due to factors such as temperature changes and vibrations, which in turn affects the bonding accuracy.
An error detection unit is set up in the optical calibration imaging system. By detecting the light source and optical components, a detection image is formed in the first and second imaging units. The actual offset caused by the optical device is calculated, and error compensation is performed during the alignment process.
This improves the alignment accuracy during wafer bonding, ensuring the accuracy of alignment and the quality of subsequent bonding.
Smart Images
Figure CN2026072597_23072026_PF_FP_ABST
Abstract
Description
Optical calibration imaging system and optical calibration method
[0001] This application claims priority to Chinese Patent Application No. 202510060276.7, filed with the Chinese Patent Office on January 15, 2025, the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of optical technology, and for example to an optical calibration imaging system and an optical calibration method. Background Technology
[0003] With the continuous development of semiconductor technology, the feature size of chips is becoming smaller and smaller. In the wafer bonding process, alignment accuracy needs to reach the submicron or even nanometer level. In the top-and-bottom aligned microscopic imaging observation system, the top and bottom imaging systems are affected by temperature changes, vibrations, etc., which cause random or trend-like relative displacement during the alignment process, resulting in a decrease in alignment accuracy and thus affecting the bonding accuracy. Summary of the Invention
[0004] This application provides an optical calibration imaging system and an optical calibration method to solve the problem of low wafer alignment accuracy in related technologies.
[0005] This application provides an optical calibration imaging system, including: a first imaging unit, a second imaging unit, an error detection unit, and a control unit; the control unit is communicatively connected to the first imaging unit and the second imaging unit.
[0006] The error detection unit includes a detection light source and a first optical component; the detection light source is configured to emit detection light to the first optical component, and the first optical component is configured to transport the detection light along a first detection optical path to a first imaging unit and along a second detection optical path to a second imaging unit; the first imaging unit is configured to receive the detection light and generate a first detection image, and the second imaging unit is configured to receive the detection light and generate a second detection image.
[0007] The first imaging unit is configured to acquire a first imaging image when the first sample is located in the first imaging optical path; the second imaging unit is configured to acquire a second imaging image when the second sample is located in the second imaging optical path;
[0008] The second detection optical path is multiplexed into part of the first imaging optical path and part of the second imaging optical path;
[0009] The control unit determines the actual amount of the second sample to be moved based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
[0010] Optionally, the optical calibration imaging system may also include a frame;
[0011] The framework comprises a first section, a second section, and a third section; the first section connects the second and third sections.
[0012] The first imaging unit and the error detection unit are disposed in the accommodating space of the second section; the second imaging unit is disposed in the accommodating space of the third section; the first sample and the second sample are disposed between the second section and the third section.
[0013] Optionally, the first optical component includes a first lens, a first beam splitter, and a first reflector arranged sequentially along the emission direction of the detection light; the detection light source is disposed on the focal plane of the first lens;
[0014] The first lens is configured to receive the detection light beam and project it parallel to the first beam splitter. The first beam splitter splits the beam into a detection light beam that propagates along the first detection light path and another detection light beam that continues to propagate along the direction of the detection light beam's emission. The first reflector receives the detection light beam and reflects it onto the second detection light path.
[0015] Optionally, the first detection optical path includes a second beam splitter and a first tube lens; the first imaging unit is disposed on the focal plane of the first tube lens;
[0016] The second beam splitter is configured to receive the detection light beam split by the first beam splitter and reflect the detection light beam to the first tube lens. The first tube lens is configured to receive the detection light beam and transmit it to the first imaging unit.
[0017] Optionally, the detection light source includes a point light source and a shaping unit;
[0018] The point light source is configured to emit light to the shaping unit, which is configured to shape the light into a detection light and output it; the shaping unit is located on the focal plane of the first lens.
[0019] Optionally, the first imaging optical path includes a first light source and a second optical component; the second imaging optical path includes a second light source and a third optical component.
[0020] The first light source is configured to emit a first imaging beam to the second optical component, and the second optical component is configured to receive the first imaging beam and transmit it to the first sample, and is also configured to receive the first imaging beam reflected by the first sample and transmit the first imaging beam to the first imaging unit.
[0021] The second light source is configured to emit a second imaging beam to the third optical component. The third optical component is configured to receive the second imaging beam and transmit it to the second sample. It is also configured to receive the second imaging beam reflected by the second sample and transmit the second imaging beam to the second imaging unit.
[0022] Optionally, the second optical component includes a second lens, a third beam splitter, and a fourth beam splitter arranged sequentially along the propagation direction of the first imaging beam reflected from the first sample;
[0023] The third optical component includes a third lens, a fifth beam splitter, and a second reflecting mirror arranged sequentially along the propagation direction of the second imaging beam reflected by the second sample.
[0024] Optionally, the first imaging optical path also includes a fourth lens; the fourth lens is disposed between the first light source and the second optical component and on the propagation path of the first imaging beam; the focal point of the fourth lens coincides with the focal point of the second lens;
[0025] The second imaging optical path also includes a fifth lens; the fifth lens is disposed between the second light source and the third optical component and on the propagation path of the second imaging beam; the focal point of the fifth lens coincides with the focal point of the third lens.
[0026] Optionally, a second tube lens may also be included in the second imaging optical path;
[0027] The second tube lens is positioned between the second imaging unit and the third optical component and along the propagation path of the second imaging beam; the second imaging unit is located on the focal plane of the second tube lens.
[0028] This application provides an optical calibration method, which is applied in an optical calibration imaging system;
[0029] Optical calibration methods include:
[0030] Acquire the first detection image and the second detection image;
[0031] Acquire the first imaging image;
[0032] Acquire the second imaging image;
[0033] The actual amount of the second sample to be moved is determined based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
[0034] Optionally, determining the amount of the second sample to be moved based on the first detection image, the second detection image, the first imaging image, and the second imaging image includes:
[0035] The actual offset is determined based on the first and second detection images;
[0036] The theoretical amount of movement to be determined is based on the first and second imaging images.
[0037] The actual amount to be moved is determined based on the theoretical amount to be moved and the actual offset.
[0038] The technical solution of this application sets an error detection unit in the optical calibration imaging system. The error detection unit includes a detection light source and a first optical component. Before the first sample and the second sample are aligned, the error detection unit forms a first detection image and a second detection image in the first imaging unit and the second imaging unit, respectively. The control unit calculates the actual offset caused by the optical device in the optical calibration imaging system and compensates for the actual offset during the alignment of the first sample and the second sample, thereby realizing alignment error compensation and improving the alignment accuracy during wafer bonding. Attached Figure Description
[0039] Figure 1 is a schematic diagram of the optical path of a first optical calibration imaging system provided according to an embodiment of this application;
[0040] Figure 2 is a schematic diagram of the electrical connections of a first optical calibration imaging system provided according to an embodiment of this application;
[0041] Figure 3 is a schematic diagram of the optical path of a second optical calibration imaging system provided according to an embodiment of this application;
[0042] Figure 4 is a schematic diagram of the optical path of a third optical calibration imaging system provided according to an embodiment of this application;
[0043] Figure 5 is a schematic diagram of the appearance of an optical calibration imaging system according to an embodiment of this application;
[0044] Figure 6 is a flowchart of a first optical calibration method provided according to an embodiment of this application;
[0045] Figure 7 is the structural flowchart corresponding to Figure 6;
[0046] Figure 8 is a flowchart of a second optical calibration method provided according to an embodiment of this application. Detailed Implementation
[0047] The technical solutions of the embodiments of this application will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort should fall within the scope of protection of this application.
[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.
[0049] Figure 1 is a schematic diagram of the optical path of a first optical calibration imaging system according to an embodiment of this application; Figure 2 is a schematic diagram of the electrical connection of the first optical calibration imaging system according to an embodiment of this application; Figure 3 is a schematic diagram of the optical path of a second optical calibration imaging system according to an embodiment of this application; and Figure 4 is a schematic diagram of the optical path of a third optical calibration imaging system according to an embodiment of this application. Referring to Figures 1, 2, 3, and 4, the optical calibration imaging system includes: a first imaging unit 1, a second imaging unit 2, an error detection unit 3, and a control unit 4; the control unit 4 is communicatively connected to the first imaging unit 1 and the second imaging unit 2.
[0050] Error detection unit 3 includes detection light source 31 and first optical component 32; detection light source 31 is configured to emit detection light a to first optical component 32, and first optical component 32 is configured to transport detection light a to first imaging unit 1 along first detection optical path and to second imaging unit 2 along second detection optical path; first imaging unit 1 is configured to receive detection light a to generate first detection image, and second imaging unit 2 is configured to receive detection light a to generate second detection image;
[0051] The first imaging unit 1 is configured to acquire a first imaging image when the first sample 51 is located in the first imaging optical path; the second imaging unit 2 is configured to acquire a second imaging image when the second sample 52 is located in the second imaging optical path.
[0052] The second detection optical path is multiplexed into part of the first imaging optical path and part of the second imaging optical path;
[0053] The control unit 4 determines the actual amount to be moved of the second sample 52 based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
[0054] The first imaging unit 1 and the second imaging unit 2 can be devices that convert light signals into electrical signals and form images. For example, a camera.
[0055] The error detection unit 3 can be configured to generate a first detection image and a second detection image in the first imaging unit 1 and the second imaging unit 2. The error detection unit 3 includes a detection light source 31 and a first optical component 32. The detection light ray a emitted by the detection light source 31 passes through the first optical component 32 and enters the first detection optical path and the second detection optical path. It is incident on the first imaging unit 1 through the first detection optical path and on the second imaging unit 2 through the second detection optical path. At this time, the first imaging unit 1 and the second imaging unit 2 respectively form the first detection image and the second detection image. It can be understood that the shape and size of the light spot on the first detection image and the second detection image are determined by the detection light ray a emitted by the detection light source 31, and theoretically the first detection image and the second detection image are the same image. When there is an error in the optical calibration imaging system, the first detection image and the second detection image after passing through different optical paths will have a relative displacement, resulting in them being different. Then, the control unit 4 can determine the magnitude of the relative displacement based on the first detection image and the second detection image.
[0056] The first sample 51 and the second sample 52 can be wafers to be bonded. In the actual bonding process, the first sample 51 and the second sample 52 need to be aligned before bonding. At this time, due to the error of the optical calibration imaging system, the relative displacement, i.e., the error of the optical calibration imaging system, needs to be considered when aligning the first sample 51 and the second sample 52 to ensure the accuracy of the alignment of the first sample 51 and the second sample 52.
[0057] The first detection optical path can be configured to input the detection light ray a into the first imaging unit 1, and the second detection optical path can be configured to input the detection light ray a into the second imaging unit 2. The first imaging optical path can be configured to input the light reflected from the first sample 51 into the first imaging unit 1, and the second imaging optical path can be configured to input the light reflected from the second sample 52 into the second imaging unit 2. Since the purpose of the first and second detection images is to determine whether the optical components in the optical calibration imaging system have shifted, thus causing imaging deviation, the second detection image needs to be multiplexed from part of the first imaging optical path and part of the second imaging optical path. This results in the second detection image being an image after passing through part of the first imaging optical path and part of the second imaging optical path. Only by comparing the first and second detection images can it be determined whether the optical components in the optical calibration imaging system have shifted, thus causing imaging deviation.
[0058] It is understandable that the error detection unit 3 is set up to simulate the first imaging optical path and the second imaging optical path through the first detection optical path and the second detection optical path to perform imaging and comparison, and to determine whether the image after passing through the first imaging optical path and the second imaging optical path is compared with the image without passing through the first imaging optical path and the second imaging optical path, thereby determining the offset caused by the device in the first imaging optical path and the second imaging optical path.
[0059] Specifically, the alignment process of the first sample 51 and the second sample 52 is as follows:
[0060] First, the detection light source 31 is turned on, allowing the detection light beam a to enter the first optical component 32. The first optical component 32 splits the detection light beam a into a first detection optical path and a second detection optical path. The light beam enters the first imaging unit 1 along the first detection optical path to form a first detection image, and enters the second imaging unit 2 along the second detection optical path to form a second detection image. The control unit 4 receives the first and second detection images and determines the actual offset. The first sample 51 is then moved onto the first imaging optical path. The reflected light from the first sample 51 enters the first imaging unit 1 along the first imaging optical path. During this process, the clearest first imaging image with the marked points can be obtained by detecting the image in the first imaging unit 1 and the marked points on the image. At this time, the position of the first sample 51 is recorded and the first sample 51 is removed. The second sample 52 is then moved to the second imaging optical path. The reflected light from the second sample 52 is incident on the second imaging unit 2 along the second imaging optical path to form a second imaging image. At this time, the control unit 4 calculates the theoretical amount to be moved by combining the first imaging image and the second imaging image, and determines the actual amount to be moved by combining the amount to be moved and the actual offset. The first sample 51 is then moved to the previously recorded position, completing the alignment of the first sample 51 and the second sample 52, which improves the accuracy of subsequent bonding.
[0061] The technical solution of this application embodiment sets an error detection unit in the optical calibration imaging system. The error detection unit includes a detection light source and a first optical component. Before the first sample and the second sample are aligned, the error detection unit forms a first detection image and a second detection image in the first imaging unit and the second imaging unit, respectively. The control unit calculates the actual offset caused by the optical device in the optical calibration imaging system and compensates for the actual offset during the alignment of the first sample and the second sample, thereby realizing alignment error compensation and improving the alignment accuracy during wafer bonding.
[0062] Optionally, Figure 5 is a schematic diagram of the appearance of an optical calibration imaging system provided according to an embodiment of the present application. As shown in Figures 1 and 5, the optical calibration imaging system also includes a frame 90.
[0063] The frame 90 includes a first part 904, a second part 902, and a third part 903; the first part 904 connects the second part 902 and the third part 903;
[0064] The first imaging unit 1 and the error detection unit 3 are disposed in the accommodating space of the second section 902; the second imaging unit 2 is disposed in the accommodating space of the third section 903; the first sample 51 and the second sample 52 are disposed between the second section 902 and the third section 903.
[0065] The frame 90 can be configured to integrate an optical calibration imaging system, housing the first imaging unit 1, the second imaging unit 2, and the error detection unit 3 within its accommodating space. The first section 904 can connect the second section 902 and the third section 903. The second section 902 can accommodate the first imaging unit 1 and the error detection unit 3, while the third section 903 can accommodate the second imaging unit 2. The first section 904 connects the second section 902 and the third section 903 into a single unit, facilitating detection movement. During the alignment of the first sample 51 and the second sample 52, image acquisition and alignment can be achieved by moving the first sample 51 and the second sample 52 to the detection position between the second section 902 and the third section 903.
[0066] Understandably, in actual optical calibration imaging systems, space is needed between the second section 902 and the third section 903 to accommodate the first sample 51 and the second sample 52, and a mobile device, such as a stage, is also required to accommodate them. Therefore, the first section 904 connecting the second section 902 and the third section 903 is often large, meaning the first section 904 is large along the direction from the second section 902 to the third section 903. When the optical calibration imaging system is affected by mechanical vibration, stress, thermal expansion coefficient, etc., the frame 90 will deform to a certain extent, leading to errors in the optical calibration imaging system. The larger the size of the first section 904, the greater the error. In this embodiment, the optical path set in the optical calibration imaging system can be used to detect whether an error has occurred and to perform error compensation.
[0067] For example, the first imaging unit 11, the second imaging unit 22, and the error detection unit 3 are arranged in the accommodating space of the C-shaped frame 90. The C-shaped frame 90 is a whole, comprising three main parts: a first part 904, a second part 902, and a third part 903. The first part 904 is omitted, and its length is determined according to actual application requirements. When the overall structure of the C-shaped frame 90 is affected by temperature changes, vibrations, or random or trend-based relative displacement during alignment, the third part 903, due to its length, will further amplify the error. Therefore, the actual offset is calculated through imaging by the error detection unit 3 to ensure alignment accuracy.
[0068] Optionally, referring to Figures 1, 2, 3 and 4, the first optical component 32 includes a first lens 321, a first beam splitter 322 and a first reflector 323 arranged sequentially along the emission direction of the detection ray a; the detection light source 31 is disposed on the focal plane of the first lens 321.
[0069] The first lens 321 is configured to receive the detection light beam a and emit it in parallel to the first beam splitter 322. The first beam splitter 322 splits the beam into a detection light beam a that propagates along the first detection optical path and another detection light beam a that continues to propagate along the emission direction of the detection light beam a. The first reflector 323 receives the detection light beam a and reflects it onto the second detection optical path.
[0070] Along the emission direction of the detection light ray a, a first lens 321, a first beam splitter 322, and a first reflector 323 are sequentially arranged. The first lens 321 integrates the detection light ray a; the first beam splitter 322 splits the beam so that the detection light ray a enters the first imaging unit 1 and the second imaging unit 2 respectively; the first reflector 323 changes the optical path and transmits the detection light ray a to the second detection optical path.
[0071] Specifically, the detection light source 31 emits a detection ray a to the first lens 321. The detection light source 31 is positioned on the focal plane of the first lens 321. The detection light source 31 can be a point light source. The point light source emits from the focal point of the first lens 321, making the detection ray a parallel ray after passing through the first lens 321, thus improving the imaging quality of the first imaging unit 1 and the second imaging unit 2. The detection ray a after passing through the first lens 321 is incident on the first beam splitter 322. The first beam splitter 322 can be a semi-transparent and semi-reflective mirror, reflecting part of the detection ray a onto the first detection optical path and incident on the first imaging unit 1 along the first detection optical path; it also transmits part of the detection ray a onto the first reflecting mirror 323, which reflects the detection ray a onto the second detection optical path and incident on the second imaging unit 2 along the second detection optical path.
[0072] The technical solution of this application embodiment achieves the purpose of transmitting detection light to the first detection optical path and the second detection optical path by setting a first lens, a first beam splitter and a first reflector in the first optical component, thereby ensuring the imaging quality of the first imaging unit and the second imaging unit.
[0073] Optionally, referring to Figures 1, 2, 3 and 4, the first detection optical path includes a second beam splitter 33 and a first tube lens 34; the first imaging unit 1 is disposed on the focal plane of the first tube lens 34.
[0074] The second beam splitter 33 is configured to receive the detection light beam a split by the first beam splitter 322 and reflect the detection light beam a to the first tube lens 34. The first tube lens 34 is configured to receive the detection light beam a and transmit it to the first imaging unit 1.
[0075] The first detection optical path includes a second beam splitter 33 and a first tube lens 34, which can be configured to deliver the detection light beam a to the first imaging unit 1. The first imaging unit 1 is disposed on the focal plane of the first tube lens 34. Specifically, the photosensitive target surface of the first imaging unit 1 can be disposed on the focal plane of the first tube lens 34, so that the first imaging unit 1 receives the detection light beam a converged by the first tube lens 34, thereby improving the imaging quality.
[0076] Specifically, the second beam splitter 33 receives the detection light beam a split by the first beam splitter 322 and reflects the detection light beam a into the first tube lens 34. The detection light beam a, after passing through the first tube lens 34, converges into the first imaging unit 1, and the first imaging unit 1 performs imaging.
[0077] It is understood that the second beam splitter 33 in the embodiments of this application may have both transmission and reflection functions, so that when light is transmitted from the first imaging optical path, the second beam splitter 33 can transmit light into the first imaging unit 1.
[0078] The technical solution of this application embodiment ensures the quality of the first detection image by setting a second beam splitter and a first tube lens in the first detection optical path so that the detection light is transmitted to the first imaging unit.
[0079] Optionally, referring to Figures 1, 2, 3 and 4, the detection light source 31 includes a point light source 311 and a shaping unit 312;
[0080] Point light source 311 is configured to emit light to shaping unit 312, and shaping unit 312 is configured to shape the light into detection light a and output it; shaping unit 312 is located on the focal plane of first lens 321.
[0081] The shaping unit 312 can be configured to shape the light emitted from the point light source 311. The purpose of the shaping unit 312 is to facilitate the calculation of the actual offset by comparing the light spots of the first detection image and the second detection image. In some embodiments, the shaping unit 312 can be a negative crosshair, with only the central crosshair passing through and the rest being blocked by the chromium layer, so that a cross-shaped light spot appears on the first detection image and the second detection image, which facilitates the calculation of the actual offset.
[0082] The shaping unit 312 is located on the focal plane of the first lens 321, so that the cross-shaped light rays form a parallel cross image after passing through the first lens 321, thus ensuring the imaging quality of the first imaging unit 1 and the second imaging unit 2.
[0083] The technical solution of this application embodiment sets a point light source and a shaping unit in the detection light source, so that the light emitted from the point light source is shaped by the shaping unit and then enters the first imaging unit and the second imaging unit for imaging. This makes it easier for the control unit to calculate the actual offset based on the first detection image and the second detection image, thereby improving the alignment accuracy.
[0084] Optionally, referring to Figures 1, 2, 3 and 4, the first imaging optical path includes a first light source 6 and a second optical component 7; the second imaging optical path includes a second light source 8 and a third optical component 9.
[0085] The first light source 6 is configured to emit a first imaging beam b to the second optical component 7. The second optical component 7 is configured to receive the first imaging beam b and transmit it to the first sample 51. It is also configured to receive the first imaging beam b reflected by the first sample 51 and transmit the first imaging beam b to the first imaging unit 1.
[0086] The second light source 8 is configured to emit the second imaging beam c to the third optical component 9. The third optical component 9 is configured to receive the second imaging beam c and transmit it to the second sample 52. It is also configured to receive the second imaging beam c reflected by the second sample 52 and transmit the second imaging beam c to the second imaging unit 2.
[0087] The first imaging optical path includes a first light source 6 and a second optical component 7. The first light source 6 can be configured to provide light for imaging the first sample 51 in the first imaging unit 1, and the second optical component 7 can be configured to transmit the first imaging beam b of the first light source 6. The second imaging optical path includes a second light source 8 and a third optical component 9. The second light source 8 can be configured to provide light for imaging the second sample 52 in the second imaging unit 2, and the third optical component 9 can be configured to transmit the second imaging beam c of the second light source 8.
[0088] Specifically, during wafer alignment, the first light source 6 emits a first imaging beam b to the second optical component 7. The second optical component 7 transmits the first imaging beam b to the first sample 51. The first sample 51 reflects the first imaging beam b back to the second optical component 7, which then transmits the reflected first imaging beam b to the first imaging unit 1 for imaging. Similarly, the second light source 8 emits a second imaging beam c to the third optical component 9. The third optical component 9 receives and transmits the second imaging beam c to the second sample 52. The second sample 52 reflects the second imaging beam c back to the third optical component 9, which then transmits the second imaging beam c to the second imaging unit 2.
[0089] It is understood that in the optical calibration imaging system of this application embodiment, the first light source 6 and the second light source 8 can be arranged relative to each other; the second optical component 7 and the third optical component 9 can be arranged relative to each other; the first sample 51 and the second sample 52 can be arranged in the gap between the second optical component 7 and the third optical component 9, and there are no optical devices between the first sample 51 and the second sample 52. This arrangement allows the first sample 51 and the second sample 52 to have the smallest possible distance during the alignment process, so as to improve the accuracy and reduce the error in the subsequent bonding process.
[0090] The technical solution of this application embodiment, by setting a first light source and a second optical component in the first imaging optical path, and setting a second light source and a third optical component in the second imaging optical path, ensures that the first sample is imaged in the first imaging unit and the second sample is imaged in the second imaging unit, thereby improving the alignment accuracy.
[0091] Optionally, continuing to refer to Figures 1, 2, 3 and 4, the second optical component 7 includes a second lens 71, a third beam splitter 72 and a fourth beam splitter 73 arranged sequentially along the propagation direction of the first imaging beam b reflected by the first sample 51;
[0092] The third optical component 9 includes a third lens 91, a fifth beam splitter 92, and a second reflecting mirror 93 arranged sequentially along the propagation direction of the second imaging beam c reflected by the second sample 52.
[0093] Along the propagation direction of the second imaging beam c reflected by the second sample 52, a second lens 71, a third beam splitter 72, and a fourth beam splitter 73 are sequentially arranged. The second lens 71 can be configured to converge the first imaging beam b onto the surface of the first sample 51. Both the third beam splitter 72 and the fourth beam splitter 73 have transmission and reflection functions. The third beam splitter 72 reflects the first imaging beam b emitted by the first light source 6 onto the second lens 71, and is also configured to transmit the first imaging beam b reflected by the first sample 51 onto the fourth beam splitter 73. The fourth beam splitter 73 reflects the first imaging beam b into the first imaging unit 1.
[0094] Along the propagation direction of the second imaging beam c reflected by the second sample 52, a third lens 91, a fifth beam splitter 92, and a second reflecting mirror 93 are sequentially arranged. The third lens 91 can be configured to converge the second imaging beam c onto the surface of the second sample 52. The fifth beam splitter 92 has transmission and reflection functions. The fifth beam splitter 92 reflects the second imaging beam c emitted by the second light source 8 onto the third lens 91. It is also configured to transmit the second imaging beam c reflected by the second sample 52 onto the second reflecting mirror 93. The second reflecting mirror 93 reflects the second imaging beam c into the first imaging unit 1.
[0095] Understandably, when the fourth beam splitter 73 has transmission and reflection functions, it can transmit the detection light beam a reflected by the first reflecting mirror 323 to the third beam splitter 72. The third beam splitter 72 then transmits the light beam a to the fifth beam splitter 92 and the second reflecting mirror 93, thereby transmitting the detection light beam a to the second imaging unit 2. This achieves the multiplexing of the second detection optical path into part of the first imaging optical path and part of the second imaging optical path. Simultaneously, the fourth beam splitter 73 can reflect the first imaging beam b to the second beam splitter 33. The second beam splitter 33 transmits the light beam b through the second lens 71 to the first imaging unit 1, completing the integration of the optical paths.
[0096] In some embodiments, the first imaging optical path further includes a fourth lens 61; the fourth lens 61 is disposed between the first light source 6 and the second optical component 7 and on the propagation path of the first imaging beam b; the focal point of the fourth lens 61 coincides with the focal point of the second lens 71; the second imaging optical path further includes a fifth lens 81; the fifth lens 81 is disposed between the second light source 8 and the third optical component 9 and on the propagation path of the second imaging beam c; the focal point of the fifth lens 81 coincides with the focal point of the third lens 91. Wherein, the focal point of the fourth lens 61 coincides with the focal point of the second lens 71, and the first imaging beam b, after passing through the fourth lens 61, is focused onto the third beam splitter 72 and then incident onto the second lens 71 through the third beam splitter 72, thus improving the imaging quality of the first imaging beam b; the focal point of the fifth lens 81 coincides with the focal point of the third lens 91, and the second imaging beam c, after passing through the fifth lens 81, is focused onto the fifth beam splitter 92 and then incident onto the third lens 91 through the fifth beam splitter 92, thus improving the imaging quality of the second imaging beam c.
[0097] In some embodiments, the second imaging optical path further includes a second tube lens 82; the second tube lens 82 is disposed between the second imaging unit 2 and the third optical component 9 and on the propagation path of the second imaging beam c; the second imaging unit 2 is located on the focal plane of the second tube lens 82. Specifically, the second imaging unit 2 is disposed on the focal plane of the second tube lens 82, and a photosensitive target surface of the second imaging unit 2 may be disposed on the focal plane of the second tube lens 82, so that the second imaging unit 2 receives the second imaging light rays converged by the second tube lens 82, thereby improving the imaging quality.
[0098] The technical solution of this application embodiment improves alignment accuracy by setting a second lens, a third beam splitter and a fourth beam splitter in the second optical component, and a third lens, a fifth beam splitter and a second reflector in the third optical component, thereby ensuring the transmission of the first imaging beam and the multiplexing of the optical path.
[0099] Based on the same application concept, Figure 6 is a flowchart of the first optical calibration method provided according to the embodiment of this application, and Figure 7 is a structural flowchart corresponding to Figure 6. In conjunction with Figures 1, 2, 3, 4 and Figures 6 and 7, the embodiment of this application also provides an optical calibration method, which is applied in an optical calibration imaging system.
[0100] Optical calibration methods include:
[0101] S10. Obtain the first detection image and the second detection image. As shown in step 7(1).
[0102] In order to ensure the accuracy of the actual offset calculation, the first detection image and the second detection image are acquired before the first sample 51 and the second sample 52 are aligned, so as to calculate the actual offset in advance.
[0103] S11. Obtain the first imaging image. As shown in step 7(2).
[0104] After acquiring the first detection image and the second detection image, the alignment process of the first sample 51 and the second sample 52 is entered. First, the first sample 51 is moved to acquire the first imaging image.
[0105] S12. Obtain the second imaging image. As shown in step 7(3).
[0106] In this process, the first sample 51 is fixed in position and a first imaging image is acquired, then the second sample 52 is moved to acquire a second imaging image.
[0107] S13. Determine the actual amount of the second sample to be moved based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
[0108] Specifically, the alignment process of the first sample 51 and the second sample 52 is as follows:
[0109] First, the detection light source 31 is turned on, allowing the detection light beam a to enter the first optical component 32. The first optical component 32 splits the detection light beam a into a first detection optical path and a second detection optical path. The light beam enters the first imaging unit 1 along the first detection optical path to form a first detection image, and enters the second imaging unit 2 along the second detection optical path to form a second detection image. The control unit 4 receives the first and second detection images and determines the actual offset. The first sample 51 is then moved onto the first imaging optical path. The reflected light from the first sample 51 enters the first imaging unit 1 along the first imaging optical path. During this process, the clearest first imaging image with the marked points can be obtained by detecting the image in the first imaging unit 1 and the marked points on the image. At this time, the position of the first sample 51 is recorded and the first sample 51 is removed. The second sample 52 is then moved to the second imaging optical path. The reflected light from the second sample 52 is incident on the second imaging unit 2 along the second imaging optical path to form a second imaging image. At this time, the control unit 4 calculates the theoretical amount to be moved by combining the first imaging image and the second imaging image, and determines the actual amount to be moved by combining the amount to be moved and the actual offset. The first sample 51 is then moved to the previously recorded position, completing the alignment of the first sample 51 and the second sample 52, which improves the accuracy of subsequent bonding.
[0110] In some embodiments, the first sample 51 and the second sample 52 can be placed on corresponding platforms and moved.
[0111] The technical solution of this application embodiment obtains a first detection image and a second detection image, calculates the actual offset caused by the optical device in the optical calibration imaging system based on the first detection image and the second detection image, and compensates for the actual offset during the alignment process of the first sample and the second sample, thereby realizing alignment error compensation and improving the alignment accuracy during wafer bonding.
[0112] Based on the above embodiments, Figure 8 is a flowchart of a second optical calibration method provided according to an embodiment of this application. As shown in Figure 8, the optical calibration method includes:
[0113] S20. Obtain the first detection image and the second detection image.
[0114] S21. Acquire the first imaging image.
[0115] S22. Acquire the second imaging image.
[0116] S23. Determine the actual offset based on the first detection image and the second detection image.
[0117] The actual offset can be the deformation of the optical calibration imaging system's own hardware due to environmental temperature, vibration, and other factors, which in turn causes the image to shift.
[0118] S24. Determine the theoretical amount of movement based on the first imaging image and the second imaging image.
[0119] The theoretical amount to be moved can be the theoretical deviation distance between the center of the second sample and the center of the first sample.
[0120] S25. Determine the actual amount to be moved based on the theoretical amount to be moved and the actual offset.
[0121] In this case, without considering the deformation of the optical calibration imaging system's own hardware due to environmental temperature, vibration and other factors, the alignment can be completed by moving the second sample 52 only according to the theoretical amount to be moved. However, in order to compensate for the error brought by the system, the actual amount to be moved needs to be determined according to the theoretical amount to be moved and the actual offset, so as to eliminate the influence of the optical calibration imaging system's own hardware and improve the alignment accuracy.
[0122] The technical solution of this application embodiment obtains a first detection image and a second detection image, calculates the actual offset caused by the optical device in the optical calibration imaging system based on the first detection image and the second detection image, and compensates for the actual offset during the alignment process of the first sample and the second sample, thereby realizing alignment error compensation and improving the alignment accuracy during wafer bonding.
[0123] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this application can be achieved, and this is not limited herein.
[0124] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.
Claims
1. An optical calibration imaging system, comprising: The system comprises a first imaging unit, a second imaging unit, an error detection unit, and a control unit; the control unit is communicatively connected to the first imaging unit and the second imaging unit. The error detection unit includes a detection light source and a first optical component; the detection light source is configured to emit detection light rays to the first optical component, and the first optical component is configured to transport the detection light rays to the first imaging unit along a first detection optical path and to the second imaging unit along a second detection optical path; the first imaging unit is configured to receive the detection light rays and generate a first detection image, and the second imaging unit is configured to receive the detection light rays and generate a second detection image. The first imaging unit is configured to acquire a first imaging image when the first sample is located in the first imaging optical path; the second imaging unit is configured to acquire a second imaging image when the second sample is located in the second imaging optical path; The second detection optical path is multiplexed into part of the first imaging optical path and part of the second imaging optical path; The control unit is configured to determine the actual amount of the second sample to be moved based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
2. The optical calibration imaging system according to claim 1, wherein the optical calibration imaging system further comprises a frame; The frame includes a first section, a second section, and a third section; the first section connects the second section and the third section; The first imaging unit and the error detection unit are disposed in the accommodating space of the second section; the second imaging unit is disposed in the accommodating space of the third section; the first sample and the second sample are disposed between the second section and the third section.
3. The optical calibration imaging system according to claim 1, wherein, The first optical component includes a first lens, a first beam splitter, and a first reflector arranged sequentially along the emission direction of the detection light; the detection light source is disposed on the focal plane of the first lens; The first lens is configured to receive the detection light and emit it parallel to the first beam splitter, which splits the beam into the detection light that propagates along the first detection light path and the detection light that continues to propagate along the emission direction of the detection light; the first reflector receives the detection light and reflects it onto the second detection light path.
4. The optical calibration imaging system according to claim 3, wherein, The first detection optical path includes a second beam splitter and a first tube mirror; the first imaging unit is disposed on the focal plane of the first tube mirror; The second beam splitter is configured to receive the detection light beam split by the first beam splitter and reflect the detection light beam to the first tube lens. The first tube lens is configured to receive the detection light beam and transmit it to the first imaging unit.
5. The optical calibration imaging system according to claim 3, wherein, The detection light source includes a point light source and a shaping unit; The point light source is configured to emit light rays to the shaping unit, and the shaping unit is configured to shape the light rays into the detection light rays and output them; the shaping unit is disposed on the focal plane of the first lens.
6. The optical calibration imaging system according to claim 1, wherein, The first imaging optical path includes a first light source and a second optical component; the second imaging optical path includes a second light source and a third optical component. The first light source is configured to emit a first imaging beam to the second optical component, and the second optical component is configured to receive the first imaging beam and transmit it to the first sample, and is also configured to receive the first imaging beam reflected by the first sample and transmit the first imaging beam to the first imaging unit; The second light source is configured to emit a second imaging beam to the third optical component, and the third optical component is configured to receive the second imaging beam and transmit it to the second sample, and is also configured to receive the second imaging beam reflected by the second sample and transmit the second imaging beam to the second imaging unit.
7. The optical calibration imaging system according to claim 6, wherein, The second optical component includes a second lens, a third beam splitter, and a fourth beam splitter arranged sequentially along the propagation direction of the first imaging beam reflected by the first sample; The third optical component includes a third lens, a fifth beam splitter, and a second reflecting mirror arranged sequentially along the propagation direction of the second imaging beam reflected by the second sample.
8. The optical calibration imaging system according to claim 7, wherein, The first imaging optical path also includes a fourth lens; the fourth lens is disposed between the first light source and the second optical component and on the propagation path of the first imaging beam; the focal point of the fourth lens coincides with the focal point of the second lens; The second imaging optical path also includes a fifth lens; the fifth lens is disposed between the second light source and the third optical component and on the propagation path of the second imaging beam; the focal point of the fifth lens coincides with the focal point of the third lens.
9. The optical calibration imaging system according to claim 6, wherein, The second imaging optical path also includes a second tube mirror; The second tube lens is disposed between the second imaging unit and the third optical component and on the propagation path of the second imaging beam; the second imaging unit is on the focal plane of the second tube lens.
10. An optical calibration method, applied in the optical calibration imaging system according to any one of claims 1-9; The optical calibration method includes: Acquire the first detection image and the second detection image; Acquire the first imaging image; Acquire the second imaging image; The actual amount of the second sample to be moved is determined based on the first detection image, the second detection image, the first imaging image, and the second imaging image.
11. The optical calibration method according to claim 10, wherein, The step of determining the amount of the second sample to be moved based on the first detection image, the second detection image, the first imaging image, and the second imaging image includes: The actual offset is determined based on the first and second detection images; The theoretical amount of movement to be determined is based on the first and second imaging images; The actual amount to be moved is determined based on the theoretical amount to be moved and the actual offset.