An optical calibration imaging system and an optical calibration method

Abstract

The present invention discloses an optical calibration imaging system and an optical calibration method. The optical calibration imaging system includes: a first imaging unit, a second imaging unit, an error detection unit and a control unit; the error detection unit includes a detection light source and a first optical component; the detection light source is used to emit detection light to the first optical component, and the first optical component is used to transmit the detection light to the first imaging unit and to the second imaging unit; the first imaging unit is used to generate a first detection image, and the second imaging unit generates a second detection image; the control unit determines the actual amount of the second sample to be moved according to the first detection image, the second detection image, the first imaging image and the second imaging image. The technical solution of the present invention realizes alignment error compensation and improves the alignment accuracy by calculating the actual offset caused by the optical device in the optical calibration imaging system and compensating the actual offset in the wafer alignment process.

Description

Technical Field

[0001] The present invention relates to the field of optical technology, and in particular to an optical calibration imaging system and an optical calibration method. Background Art

[0002] With the continuous development of semiconductor technology, the characteristic size of chips is getting smaller and smaller. During the wafer bonding process, the alignment accuracy needs to reach the sub-micron or even nanometer level. In the upper and lower opposed microscopic imaging observation system, the upper and lower imaging systems are affected by temperature changes, vibrations, etc., and relative displacement occurs randomly or tends to occur during the alignment process, resulting in a decrease in alignment accuracy, which in turn affects the bonding accuracy. Summary of the invention

[0003] The present invention provides an optical calibration imaging system and an optical calibration method to solve the problem of low wafer alignment accuracy in the prior art.

[0004] According to one aspect of the present invention, an optical calibration imaging system is provided, comprising: a first imaging unit, a second imaging unit, an error detection unit and a control unit; the control unit is communicatively connected with the first imaging unit and the second imaging unit;

[0005] The error detection unit includes a detection light source and a first optical component; the detection light source is used to emit detection light to the first optical component, and the first optical component is used to transmit the detection light to the first imaging unit along the first detection light path and to the second imaging unit along the second detection light path; the first imaging unit is used to receive the detection light to generate a first detection image, and the second imaging unit is used to receive the detection light to generate a second detection image;

[0006] The first imaging unit is used to acquire a first imaging image when the first sample is located on a first imaging light path; the second imaging unit is used to acquire a second imaging image when the second sample is located on a second imaging light path;

[0007] The second detection optical path is multiplexed into a part of the first imaging optical path and a part of the second imaging optical path;

[0008] The control unit determines an actual amount to be moved of the second sample according to the first detection image, the second detection image, the first imaging image, and the second imaging image.

[0009] Optionally, the optical calibration imaging system further includes a frame;

[0010] The frame includes a first section, a second section and a third section; the first section connects the second section and the third section;

[0011] The first imaging unit and the error detection unit are arranged in the accommodation space of the second subsection; the second imaging unit is arranged in the accommodation space of the third subsection; and the first sample and the second sample are arranged between the second subsection and the third subsection.

[0012] Optionally, the first optical component includes a first lens, a first beam splitter and a first reflector which are sequentially arranged along the emitting direction of the detection light; the detection light source is arranged on the focal plane of the first lens;

[0013] The first lens is used to receive the detection light and emit it in parallel to the first beam splitter, and the first beam splitter is used to split it into the detection light propagating along the first detection light path and the detection light continuing to propagate along the detection light emission direction; the first reflector receives the detection light and reflects it to the second detection light path.

[0014] Optionally, the first detection optical path includes a second beam splitter and a first tube lens; the first imaging unit is arranged on a focal plane of the first tube lens;

[0015] The second beam splitter is used to receive the detection light split by the first beam splitter and reflect the detection light to the first tube lens. The first tube lens is used to receive the detection light and transmit it to the first imaging unit.

[0016] Optionally, the detection light source includes a point light source and a shaping unit;

[0017] The point light source is used to emit light to the shaping unit, and the shaping unit is used to shape the light into detection light and output it; the shaping unit is arranged on the focal plane of the first lens.

[0018] Optionally, the first imaging light path includes a first light source and a second optical component; the second imaging light path includes a second light source and a third optical component;

[0019] The first light source is used to emit a first imaging light beam to the second optical component, the second optical component is used to receive the first imaging light beam and transmit it to the first sample, and is also used to receive the first imaging light beam reflected by the first sample and transmit the first imaging light beam to the first imaging unit;

[0020] The second light source is used to emit a second imaging beam to the third optical component, and the third optical component is used to receive the second imaging beam and transmit it to the second sample, and also to receive the second imaging beam reflected by the second sample and transmit it to the second imaging unit.

[0021] Optionally, the second optical component includes a second lens, a third beam splitter and a fourth beam splitter which are sequentially arranged along a propagation direction of the first imaging light beam reflected by the first sample;

[0022] The third optical component includes a third lens, a fifth beam splitter and a second reflector which are sequentially arranged along a propagation direction of the second imaging light beam reflected by the second sample.

[0023] Optionally, the first imaging light path further includes a fourth lens; the fourth lens is arranged between the first light source and the second optical component and on the propagation path of the first imaging light beam; the focus of the fourth lens coincides with the focus of the second lens;

[0024] The second imaging light path also includes a fifth lens; the fifth lens is arranged between the second light source and the third optical component and on the propagation path of the second imaging light beam; the focus of the fifth lens coincides with the focus of the third lens.

[0025] Optionally, the second imaging optical path further includes a second tube lens;

[0026] The second tube lens is arranged between the second imaging unit and the third optical component and on the propagation path of the second imaging light beam; the second imaging unit is on the focal plane of the second tube lens.

[0027] According to another aspect of the present invention, there is provided an optical calibration method, which is applied in an optical calibration imaging system;

[0028] Optical calibration methods include:

[0029] Acquire a first detection image and a second detection image;

[0030] Acquire a first imaging image;

[0031] acquiring a second imaging image;

[0032] The actual amount of the second sample to be moved is determined according to the first detection image, the second detection image, the first imaging image, and the second imaging image.

[0033] Optionally, determining the amount of the second sample to be moved according to the first detection image, the second detection image, the first imaging image, and the second imaging image includes:

[0034] determining an actual offset according to the first detection image and the second detection image;

[0035] Determine a theoretical amount to be moved based on the first image and the second image;

[0036] The actual amount to be moved is determined based on the theoretical amount to be moved and the actual offset.

[0037] The technical solution of the present invention is to set an error detection unit in the optical calibration imaging system, wherein 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 is used to form 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 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.

[0038] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 is a schematic diagram of an optical path of a first optical calibration imaging system provided according to an embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of electrical connections of a first optical calibration imaging system provided according to an embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of an optical path of a second optical calibration imaging system provided according to an embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of an optical path of a third optical calibration imaging system provided according to an embodiment of the present invention;

[0044] Figure 5 is a schematic diagram of the appearance of an optical calibration imaging system provided according to an embodiment of the present invention;

[0045] Figure 6 is a flow chart of a first optical calibration method provided according to an embodiment of the present invention;

[0046] Figure 7 yes Figure 6 The corresponding structural flow chart;

[0047] Figure 8 is a flow chart of a second optical calibration method provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0049] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein.

[0050] Figure 1 is a schematic diagram of an optical path of a first optical calibration imaging system provided according to an embodiment of the present invention, Figure 2 is a schematic diagram of electrical connections of a first optical calibration imaging system provided according to an embodiment of the present invention, Figure 3 is a schematic diagram of an optical path of a second optical calibration imaging system provided according to an embodiment of the present invention, Figure 4 FIG. 1 is a schematic diagram of an optical path of a third optical calibration imaging system provided according to an embodiment of the present invention. Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, 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 with the first imaging unit 1 and the second imaging unit 2;

[0051] The error detection unit 3 includes a detection light source 31 and a first optical component 32; the detection light source 31 is used to emit a detection light a to the first optical component 32, and the first optical component 32 is used to transmit the detection light a to the first imaging unit 1 along the first detection light path and to the second imaging unit 2 along the second detection light path; the first imaging unit 1 is used to receive the detection light a to generate a first detection image, and the second imaging unit 2 is used to receive the detection light a to generate a second detection image;

[0052] The first imaging unit 1 is used to obtain a first imaging image when the first sample 51 is located on a first imaging optical path; the second imaging unit 2 is used to obtain a second imaging image when the second sample 52 is located on a second imaging optical path;

[0053] The second detection optical path is multiplexed into a part of the first imaging optical path and a part of the second imaging optical path;

[0054] The control unit 4 determines the actual amount to be moved of the second sample 52 according to the first detection image, the second detection image, the first imaging image, and the second imaging image.

[0055] The first imaging unit 1 and the second imaging unit 2 may be devices that convert optical signals into electrical signals and form images, for example, cameras.

[0056] Among them, the error detection unit 3 can be used to generate the first detection image and the 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 a emitted by the detection light source 31 enters the first detection light path and the second detection light path through the first optical component 32, and is incident on the first imaging unit 1 from the first detection light path, and is incident on the second imaging unit 2 from the second detection light path. At this time, the first imaging unit 1 and the second imaging unit 2 form the first detection image and the second detection image respectively. It can be understood that the size of the light spot shape on the first detection image and the second detection image is determined by the detection light 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 light paths will produce relative displacement, resulting in the difference between the two, and then the control unit 4 can determine the size of the relative displacement according to the first detection image and the second detection image.

[0057] The first sample 51 and the second sample 52 may 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.

[0058] Among them, the first detection optical path can be used to input the detection light a into the first imaging unit 1, the second detection optical path can be used to input the detection light a into the second imaging unit 2, the first imaging optical path can be used to input the light reflected by the first sample 51 into the first imaging unit 1, and the second imaging optical path can be used to input the light reflected by the second sample 52 into the second imaging unit 2. Since the purpose of the first detection image and the second detection image is to determine whether the optical device in the optical calibration imaging system is offset and thus causes the imaging to be offset, the second detection image needs to be multiplexed into part of the first imaging optical path and part of the second imaging optical path, so that the second detection image is an image after passing through part of the first imaging optical path and part of the second imaging optical path. In this way, the first detection image and the second detection image are compared to determine whether the optical device in the optical calibration imaging system is offset and thus causes imaging deviation.

[0059] It can be understood that an error detection unit 3 is set to simulate the first imaging light path and the second imaging light path through the first detection light path and the second detection light path to perform imaging and comparison, and determine whether the image after passing through the first imaging light path and the second imaging light path is compared with the image that has not passed through the first imaging light path and the second imaging light path, and then determine the offset caused by the devices on the first imaging light path and the second imaging light path.

[0060] Specifically, the alignment process of the first sample 51 and the second sample 52 is as follows:

[0061] First, turn on the detection light source 31, so that the detection light a enters the first optical component 32. The first optical component 32 splits the detection light a into the first detection light path and the second detection light path, and enters the first imaging unit 1 along the first detection light path to form a first detection image, and enters the second imaging unit 2 along the second detection light path to form a second detection image. The control unit 4 receives the first detection image and the second detection image and determines the actual offset. Continue to move the first sample 51 to the first imaging light path, and the light reflected by the first sample 51 is incident on the first imaging unit 1 along the first imaging light path. In this process, the clearest first imaging image with 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 moved out. Then move the second sample 52 to the second imaging optical path, and the light reflected by 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 in combination with the first imaging image and the second imaging image, and determines the actual amount to be moved in combination with the amount to be moved and the actual offset, and moves the first sample 51 to the previously recorded position, completing the alignment of the first sample 51 and the second sample 52, thereby improving the accuracy of subsequent bonding.

[0062] The technical solution of the embodiment of the present invention is to set an error detection unit in the optical calibration imaging system, wherein 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 is used to form 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 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.

[0063] Optional, Figure 5 is a schematic diagram of the appearance of an optical calibration imaging system provided according to an embodiment of the present invention, combined with Figure 1 and Figure 5 As shown, the optical calibration imaging system further includes a frame 90;

[0064] The frame 90 includes a first sub-section 904, a second sub-section 902 and a third sub-section 903; the first sub-section 904 connects the second sub-section 902 and the third sub-section 903;

[0065] The first imaging unit 1 and the error detection unit 3 are arranged in the accommodation space of the second subsection 902 ; the second imaging unit 2 is arranged in the accommodation space of the third subsection 903 ; the first sample 51 and the second sample 52 are arranged between the second subsection 902 and the third subsection 903 .

[0066] The frame 90 can be used to integrate the optical calibration imaging system, and the first imaging unit 1, the second imaging unit 2 and the error detection unit 3 are arranged in the accommodation space of the frame 90. The first subdivision 904 can be used to connect the second subdivision 902 and the third subdivision 903, the second subdivision 902 can be used to accommodate the first imaging unit 1 and the error detection unit 3, the third subdivision 903 can be used to accommodate the second imaging unit 2, and the first subdivision 904 connects the second subdivision 902 and the third subdivision 903 as a whole, which is convenient for detecting movement. In the process of aligning the first sample 51 and the second sample 52, the first sample 51 and the second sample 52 can be moved to the detection position between the second subdivision 902 and the third subdivision 903 to complete the acquisition and alignment of the image.

[0067] It is understandable that in the optical calibration imaging system actually set up, since a space needs to be set between the second division 902 and the third division 903 to accommodate the first sample 51 and the second sample 52 and a mobile device such as a stage that can accommodate the first sample 51 and the second sample 52 is needed, the first division 904 connecting the second division 902 and the third division 903 is often large in size, that is, the first division 904 is large in size along the direction from the second division 902 to the third division 903. When the optical calibration imaging system is affected by mechanical vibration, stress, thermal expansion coefficient, etc., the frame 90 will be deformed to a certain extent, which will cause errors in the optical calibration imaging system. The larger the size of the first division 904, the greater the error. In the embodiment of the present invention, the optical path set in the optical calibration imaging system can be used to detect whether an error occurs and perform error compensation.

[0068] Exemplarily, the first imaging unit 11, the second imaging unit 22 and the error detection unit 3 are arranged in the accommodation space of the C-shaped frame 90. The C-shaped frame 90 is a whole, including the first subdivision 904, the second subdivision 902 and the third subdivision 903 as three main parts. Among them, the first subdivision 904 area is an omitted part, and the length is determined according to the actual application requirements. When the overall structure of the C-shaped frame 90 is affected by temperature changes, vibrations, etc., or when relative displacement occurs randomly or tends to occur during the alignment process, the third subdivision 903 area will further amplify the error due to the length factor. Therefore, the actual offset is calculated by imaging the error detection unit 3 to ensure the alignment accuracy.

[0069] Optional, continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the first optical component 32 includes a first lens 321, a first beam splitter 322 and a first reflector 323 which are sequentially arranged along the emitting direction of the detection light a; the detection light source 31 is arranged on the focal plane of the first lens 321;

[0070] The first lens 321 is used to receive the detection light a and emit it in parallel to the first beam splitter 322, and the first beam splitter 322 splits it into the detection light a propagating along the first detection light path and the detection light a continuing to propagate along the emission direction of the detection light a; the first reflector 323 receives the detection light a and reflects it to the second detection light path.

[0071] Among them, along the emission direction of the detection light a, the first lens 321, the first beam splitter 322 and the first reflector 323 are sequentially arranged. The first lens 321 can play the role of integrating the detection light a; the first beam splitter 322 plays the role of beam splitting, so that the detection light a is incident on the first imaging unit 1 and the second imaging unit 2 respectively; the first reflector 323 can play the role of changing the optical path, and transmit the detection light a to the second detection optical path.

[0072] Specifically, the detection light source 31 emits the detection light a to the first lens 321. The detection light source 31 is arranged on the focal plane of the first lens 321. The detection light source 31 may be a point light source. The point light source is emitted from the focus of the first lens 321 so that the detection light a passing through the first lens 321 is a parallel light, thereby improving the imaging quality of the first imaging unit 1 and the second imaging unit 2. The detection light a passing through the first lens 321 is incident on the first beam splitter 322. The first beam splitter 322 may be a semi-transparent and semi-reflective mirror, which reflects part of the detection light a onto the first detection light path and enters the first imaging unit 1 along the first detection light path; and transmits part of the detection light a to the first reflector 323. The first reflector 323 reflects the detection light a onto the second detection light path and enters the second imaging unit 2 along the second detection light path.

[0073] The technical solution of the embodiment of the present invention achieves the purpose of transmitting detection light to the first detection light path and the second detection light path by setting the first lens, the first beam splitter and the first reflector in the first optical component, thereby ensuring the imaging quality of the first imaging unit and the second imaging unit.

[0074] Optional, continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the first detection optical path includes a second beam splitter 33 and a first tube lens 34; the first imaging unit 1 is arranged on the focal plane of the first tube lens 34;

[0075] The second beam splitter 33 is used for receiving the detection light a split by the first beam splitter 322 and reflecting the detection light a to the first tube lens 34 . The first tube lens 34 is used for receiving the detection light a and transmitting it to the first imaging unit 1 .

[0076] The first detection optical path includes a second beam splitter 33 and a first tube lens 34, which can be used to transmit the detection light a to the first imaging unit 1. The first imaging unit 1 is arranged on the focal plane of the first tube lens 34, and specifically, the photosensitive target surface of the first imaging unit 1 can be arranged on the focal plane of the first tube lens 34, so that the first imaging unit 1 receives the detection light a converged by the first tube lens 34, thereby improving the imaging quality.

[0077] Specifically, the second beam splitter 33 receives the detection light a split by the first beam splitter 322 and reflects the detection light a to the first tube lens 34. The detection light a passing through the first tube lens 34 converges to the first imaging unit 1, and the first imaging unit 1 performs imaging.

[0078] It is understandable that the second beam splitter 33 in the embodiment of the present invention may have both transmission and reflection functions, so that when the light is transmitted from the first imaging optical path, the second beam splitter 33 may transmit the light into the first imaging unit 1 .

[0079] The technical solution of the embodiment of the present invention is to arrange a second beam splitter and a first tube mirror on the first detection light path so that the detection light is transmitted to the first imaging unit, thereby ensuring the quality of the first detection image.

[0080] Optional, continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the detection light source 31 includes a point light source 311 and a shaping unit 312;

[0081] The point light source 311 is used to emit light to the shaping unit 312 , and the shaping unit 312 is used to shape the light into the detection light a and output it; the shaping unit 312 is arranged on the focal plane of the first lens 321 .

[0082] Among them, the shaping unit 312 can be used to shape the light emitted by the point light source 311. The purpose of setting the shaping unit 312 is to facilitate the calculation of the actual offset according to the comparison of 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, where only the cross in the center is transparent, and the rest is blocked by the chrome layer, so that a cross-shaped light spot appears on the first detection image and the second detection image, which is convenient for calculating the actual offset.

[0083] The shaping unit 312 is arranged on the focal plane of the first lens 321 , so that the cross-shaped light forms a parallel cross image after passing through the first lens 321 , thereby ensuring the imaging quality of the first imaging unit 1 and the second imaging unit 2 .

[0084] The technical solution of the embodiment of the present invention is to set a point light source and a shaping unit in the detection light source, so that the light emitted by the point light source is shaped by the shaping unit and then enters the first imaging unit and the second imaging unit for imaging, which makes it convenient for the control unit to calculate the actual offset according to the first detection image and the second detection image, thereby improving the alignment accuracy.

[0085] Optional, continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the first imaging light path includes a first light source 6 and a second optical component 7; the second imaging light path includes a second light source 8 and a third optical component 9;

[0086] The first light source 6 is used to emit the first imaging light beam b to the second optical component 7, and the second optical component 7 is used to receive the first imaging light beam b and transmit it to the first sample 51, and is also used to receive the first imaging light beam b reflected by the first sample 51 and transmit the first imaging light beam b to the first imaging unit 1;

[0087] The second light source 8 is used to emit the second imaging beam c to the third optical component 9, and the third optical component 9 is used to receive the second imaging beam c and transmit it to the second sample 52, and also to receive the second imaging beam c reflected by the second sample 52 and transmit it to the second imaging unit 2.

[0088] The first imaging optical path includes a first light source 6 and a second optical component 7. The first light source 6 can be used to provide light for imaging the first sample 51 in the first imaging unit 1, and the second optical component 7 can be used to transmit the first imaging light 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 used to provide light for imaging the second sample 52 in the second imaging unit 2, and the third optical component 9 can be used to transmit the second imaging light beam c of the second light source 8.

[0089] Specifically, during the wafer alignment process, the first light source 6 emits the 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 to the second optical component 7, and the second optical component 7 transmits the reflected first imaging beam b to the first imaging unit 1 for imaging. Similarly, the second light source 8 emits the 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 imaging beam c reflected by the second sample 52 is transmitted to the third optical component 9, and the third optical component 9 transmits the second imaging beam c to the second imaging unit 2.

[0090] It can be understood that in the optical calibration imaging system of the embodiment of the present invention, 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 is no optical device between the first sample 51 and the second sample 52. Such an arrangement allows the distance between the first sample 51 and the second sample 52 to be as small as possible during the alignment process, so as to improve the accuracy and reduce errors in the subsequent bonding process.

[0091] The technical solution of the embodiment of the present invention ensures the imaging of the first sample in the first imaging unit and the imaging of the second sample in the second imaging unit by arranging the first light source and the second optical component on the first imaging light path and the second light source and the third optical component on the second imaging light path, thereby improving the alignment accuracy.

[0092] Optional, continue to refer to Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the second optical component 7 includes a second lens 71, a third beam splitter 72 and a fourth beam splitter 73 which are sequentially arranged along the propagation direction of the first imaging light beam b reflected by the first sample 51;

[0093] The third optical component 9 includes a third lens 91 , a fifth beam splitter 92 and a second reflector 93 which are arranged in sequence along the propagation direction of the second imaging light beam c reflected by the second sample 52 .

[0094] Among them, along the propagation direction of the second imaging light beam c reflected by the second sample 52, the second lens 71, the third beam splitter 72 and the fourth beam splitter 73 are sequentially arranged. The second lens 71 can be used to converge the first imaging light beam b onto the surface of the first sample 51, the third beam splitter 72 and the fourth beam splitter 73 both have transmission and reflection functions, the third beam splitter 72 reflects the first imaging light beam b emitted by the first light source 6 onto the second lens 71, and is also used to transmit the first imaging light beam b reflected by the first sample 51 to the fourth beam splitter 73, and the fourth beam splitter 73 reflects the first imaging light beam b into the first imaging unit 1.

[0095] Among them, along the propagation direction of the second imaging light beam c reflected by the second sample 52, the third lens 91, the fifth beam splitter 92 and the second reflector 93 are sequentially arranged. The third lens 91 can be used to converge the second imaging light beam c to the surface of the second sample 52, and the fifth beam splitter 92 has a transmission and reflection function. The fifth beam splitter 92 reflects the second imaging light beam c emitted by the second light source 8 to the third lens 91, and is also used to transmit the second imaging light beam c reflected by the second sample 52 to the second reflector 93, and the second reflector 93 reflects the second imaging light beam c to the first imaging unit 1.

[0096] It can be understood that when the fourth beam splitter 73 has a transmission and reflection function, the detection light a reflected by the first reflector 323 can be transmitted to the third beam splitter 72, and the third beam splitter 72 is further transmitted to the fifth beam splitter 92 and the second reflector 93, and the detection light a can be transmitted to the second imaging unit 2, and the second detection optical path is multiplexed into part of the first imaging optical path and part of the second imaging optical path. At the same time, the fourth beam splitter 73 can reflect the first imaging light beam b to the second beam splitter 33, and the second beam splitter 33 is transmitted through the second lens 71 to the first imaging unit 1, completing the integration of the optical path.

[0097] 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 light beam b; the focus of the fourth lens 61 coincides with the focus 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 light beam c; the focus of the fifth lens 81 coincides with the focus of the third lens 91. Among them, the focus of the fourth lens 61 coincides with the focus of the second lens 71, the first imaging light beam b passing through the fourth lens 61 is focused on the third beam splitter 72 and then incident on the second lens 71 through the third beam splitter 72, thereby improving the imaging quality of the first imaging light beam b; the focus of the fifth lens 81 coincides with the focus of the third lens 91, the second imaging light beam c passing through the fifth lens 81 is focused on the fifth beam splitter 92 and then incident on the third lens 91 through the fifth beam splitter 92, thereby improving the imaging quality of the second imaging light beam c.

[0098] 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 light beam c; the second imaging unit 2 is on the focal plane of the second tube lens 82. The second imaging unit 2 is disposed on the focal plane of the second tube lens 82, and specifically, a photosensitive target surface of the second imaging unit 2 can be disposed on the focal plane of the second tube lens 82, so that the second imaging unit 2 receives the second imaging light converged by the second tube lens 82, thereby improving the imaging quality.

[0099] The technical solution of the embodiment of the present invention ensures the transmission of the first imaging beam and the second imaging beam and the multiplexing of the optical path by arranging the second lens, the third beam splitter and the fourth beam splitter in the second optical component and the third lens, the fifth beam splitter and the second reflector in the third optical component, thereby improving the alignment accuracy.

[0100] Based on the same inventive concept, Figure 6 is a flow chart of a first optical calibration method provided according to an embodiment of the present invention. Figure 7 yes Figure 6 The corresponding structural flow chart, combined with Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 6 and Figure 7 As shown, an embodiment of the present invention further provides an optical calibration method, which is applied in an optical calibration imaging system;

[0101] Optical calibration methods include:

[0102] S10, obtaining a first detection image and a second detection image. Figure 7 (1) Steps as shown.

[0103] In order to ensure the accuracy of the calculation of the actual offset, the first detection image and the second detection image are acquired before the first sample 51 and the second sample 52 are aligned to calculate the actual offset in advance.

[0104] S11, obtaining a first imaging image. Figure 7 (2) Steps as shown.

[0105] After acquiring the first detection image and the second detection image, the first sample 51 and the second sample 52 are aligned, and the first sample 51 is first moved to acquire the first imaging image.

[0106] S12, obtaining a second imaging image. Figure 7 (3) Steps as shown.

[0107] The first sample 51 is fixed in position and a first imaging image is acquired, and then the second sample 52 is moved to acquire a second imaging image.

[0108] S13, determining the actual amount of the second sample to be moved according to the first detection image, the second detection image, the first imaging image, and the second imaging image.

[0109] Specifically, the alignment process of the first sample 51 and the second sample 52 is as follows:

[0110] First, turn on the detection light source 31, so that the detection light a enters the first optical component 32. The first optical component 32 splits the detection light a into the first detection light path and the second detection light path, and enters the first imaging unit 1 along the first detection light path to form a first detection image, and enters the second imaging unit 2 along the second detection light path to form a second detection image. The control unit 4 receives the first detection image and the second detection image and determines the actual offset. Continue to move the first sample 51 to the first imaging light path, and the light reflected by the first sample 51 is incident on the first imaging unit 1 along the first imaging light path. In this process, the clearest first imaging image with 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 moved out. Then move the second sample 52 to the second imaging optical path, and the light reflected by 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 in combination with the first imaging image and the second imaging image, and determines the actual amount to be moved in combination with the amount to be moved and the actual offset, and moves the first sample 51 to the previously recorded position, completing the alignment of the first sample 51 and the second sample 52, thereby improving the accuracy of subsequent bonding.

[0111] In some embodiments, the first sample 51 and the second sample 52 can be placed on corresponding platforms and moved.

[0112] The technical solution of the embodiment of the present invention, by acquiring a first detection image and a second detection image, calculating the actual offset caused by the optical device in the optical calibration imaging system according to the first detection image and the second detection image and compensating the actual offset in the process of aligning the first sample and the second sample, realizes alignment error compensation and improves the alignment accuracy during wafer bonding.

[0113] Based on the above embodiments, Figure 8 is a flow chart of a second optical calibration method provided according to an embodiment of the present invention. Figure 8 As shown, the optical calibration method includes:

[0114] S20, acquiring a first detection image and a second detection image.

[0115] S21, acquiring a first imaging image.

[0116] S22: Acquire a second imaging image.

[0117] S23. Determine an actual offset according to the first detection image and the second detection image.

[0118] The actual offset may be the deformation of the optical calibration imaging system's own hardware equipment due to the influence of other factors such as ambient temperature and vibration, which in turn causes the offset in the image.

[0119] S24: Determine a theoretical amount to be moved according to the first imaging image and the second imaging image.

[0120] The theoretical amount to be moved may be a theoretical deviation distance between the center of the second sample and the center of the first sample.

[0121] S25, determining the actual amount to be moved according to the theoretical amount to be moved and the actual offset.

[0122] Among them, when the deformation problem of the optical calibration imaging system's own hardware equipment caused by other factors such as ambient temperature and vibration is not considered, the alignment can be completed by moving the second sample 52 according to the theoretical amount to be moved. However, in order to compensate for the error caused by the system, the actual amount to be moved must be determined based on 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 equipment and improve the alignment accuracy.

[0123] The technical solution of the embodiment of the present invention, by acquiring a first detection image and a second detection image, calculating the actual offset caused by the optical device in the optical calibration imaging system according to the first detection image and the second detection image and compensating the actual offset in the process of aligning the first sample and the second sample, realizes alignment error compensation and improves the alignment accuracy during wafer bonding.

[0124] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0125] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An optical calibration imaging system, characterized in that: include: A first imaging unit, a second imaging unit, an error detection unit and a control unit; the control unit is communicatively connected with the first imaging unit and the second imaging unit; The error detection unit comprises a detection light source and a first optical component; the detection light source is used to emit detection light to the first optical component, and the first optical component is used to transmit the detection light to the first imaging unit along a first detection light path and to the second imaging unit along a second detection light path; The first imaging unit is used to receive the detection light to generate a first detection image, and the second imaging unit is used to receive the detection light to generate a second detection image; The first imaging unit is used to acquire a first imaging image when the first sample is located on a first imaging optical path; the second imaging unit is used to acquire a second imaging image when the second sample is located on a 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 used to determine the actual offset according to the first detection image and the second detection image; A theoretical amount to be moved is determined according to the first imaging image and the second imaging image; and an actual amount to be moved of the second sample is determined according to the theoretical amount to be moved and the actual offset.

2. The optical calibration imaging system according to claim 1, characterized in that: The optical calibration imaging system also includes 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 arranged in the accommodation space of the second subsection; The second imaging unit is disposed in the accommodation space of the third subsection; and the first sample and the second sample are disposed between the second subsection and the third subsection.

3. The optical calibration imaging system according to claim 1, characterized in that: The first optical component comprises a first lens, a first beam splitter and a first reflector which are sequentially arranged along the emitting direction of the detection light; the detection light source is arranged on the focal plane of the first lens; The first lens is used to receive the detection light and emit it in parallel to the first beam splitter, and the first beam splitter is used to split the detection light into the detection light propagating along the first detection light path and the detection light continuing 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, characterized in that: The first detection optical path includes a second beam splitter and a first tube lens; the first imaging unit is arranged on the focal plane of the first tube lens; The second beam splitter is used to receive the detection light split by the first beam splitter and reflect the detection light to the first tube lens, and the first tube lens is used to receive the detection light and transmit it to the first imaging unit.

5. The optical calibration imaging system according to claim 3, characterized in that: The detection light source includes a point light source and a shaping unit; The point light source is used to emit light to the shaping unit, and the shaping unit is used to shape the light into the detection light and output it; The shaping unit is arranged on the focal plane of the first lens.

6. The optical calibration imaging system according to claim 1, characterized in that: The first imaging light path includes a first light source and a second optical component; the second imaging light path includes a second light source and a third optical component; The first light source is used to emit a first imaging beam to the second optical component, the second optical component is used to receive the first imaging beam and transmit it to the first sample, and is also used 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 used to emit a second imaging beam to the third optical component, and the third optical component is used to receive the second imaging beam and transmit it to the second sample, and is also used to receive the second imaging beam reflected by the second sample and transmit it to the second imaging unit.

7. The optical calibration imaging system according to claim 6, characterized in that: The second optical component comprises a second lens, a third beam splitter and a fourth beam splitter which are sequentially arranged along a propagation direction of the first imaging light beam reflected by the first sample; The third optical component includes a third lens, a fifth beam splitter, and a second reflector which are sequentially arranged along a propagation direction of the second imaging light beam reflected by the second sample.

8. The optical calibration imaging system according to claim 7, characterized in that: The first imaging light path also includes a fourth lens; the fourth lens is arranged between the first light source and the second optical component and on the propagation path of the first imaging light beam; the focus of the fourth lens coincides with the focus of the second lens; The second imaging light path also includes a fifth lens; the fifth lens is arranged between the second light source and the third optical component and on the propagation path of the second imaging light beam; the focus of the fifth lens coincides with the focus of the third lens.

9. The optical calibration imaging system according to claim 6, characterized in that: The second imaging optical path also includes a second tube lens; The second tube lens is arranged between the second imaging unit and the third optical component and on the propagation path of the second imaging light beam; the second imaging unit is on the focal plane of the second tube lens.

10. An optical calibration method, characterized in that: Used in the optical calibration imaging system according to any one of claims 1 to 9; The optical calibration method comprises: Acquire a first detection image and a second detection image; Acquire a first imaging image; acquiring a second imaging image; determining an actual offset according to the first detection image and the second detection image; Determine a theoretical amount to be moved according to the first imaging image and the second imaging image; The actual amount of movement of the second sample is determined according to the theoretical amount of movement and the actual offset.

Images