Alignment device and alignment method

Abstract

The invention provides an alignment device and method, and belongs to the technical field of wafer packaging, and the device specifically comprises a first collimation unit, a first refraction unit, a second collimation unit, a second refraction unit, a beam combining and splitting prism, and an image collection unit. Wherein the optical paths of the two reflected lights reaching the imaging collection unit are consistent. By means of the processing scheme, the definition of mark imaging is improved, the response speed of the image collecting unit is increased, the response error is reduced, and high-precision alignment between the two reference plates is achieved.

Description

Technical Field

[0001] The present invention relates to the field of wafer packaging, and in particular to an alignment device and an alignment method. Background Art

[0002] With the development of the electronics industry, the functions of chips are becoming more and more complex and the sizes are becoming smaller and smaller. New semiconductor technologies that meet this demand are constantly emerging, such as wafer-level packaging, 3D chip stacking, 3D devices, silicon-on-insulator wafers, etc. The development of these technologies has driven the development of wafer bonding technology.

[0003] Wafer bonding is a technology that uses van der Waals force, molecular force, and even atomic force to bond wafers together under the action of external energy through atoms at the wafer interface. There are many existing wafer bonding processes, among which direct wafer bonding is widely used because it does not require adhesives, is carried out under normal pressure, is resistant to high temperatures, and has high output. In wafer bonding, the upper and lower wafers usually need to establish a connection between wires to realize a complete device on two or more wafers.

[0004] The degree of alignment between the upper and lower wafers is a very important parameter in wafer bonding.

[0005] In the prior art, wafer alignment usually has problems of large errors and insufficient absolute accuracy, and the alignment operation is affected by the transmittance of the reference plate. Summary of the invention

[0006] Therefore, in order to overcome the above-mentioned shortcomings of the prior art, the present invention provides an alignment device and an alignment method, wherein the alignment device can achieve high-precision alignment between a first reference plate and a second reference plate.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An alignment device, used for directly positioning a first reference plate relative to a second reference plate, comprises: a first collimating unit, a first refractive unit, a second collimating unit, a second refractive unit, a beam-combining and splitting prism, and an imaging collection unit; the first collimating unit collimates a first light beam, and refracts the first light beam to the first reference plate after passing through the first refractive unit, and the first reflected light fed back from the first reference plate passes through the beam-combining and splitting prism and irradiates the imaging collection unit to form a first light path; the second collimating unit collimates a second light beam, and refracts the second light beam to the second reference plate after passing through the second refractive unit, and the second reflected light fed back from the second reference plate passes through the beam-combining and splitting prism and irradiates the imaging collection unit to form a second light path; the optical path from the first reflected light to the imaging system is consistent with the optical path from the second reflected light to the imaging system.

[0009] Specifically, it also includes an optical path compensation structure, wherein the first reflected light is first reflected 90 degrees when passing through the inclined surface of the beam-combining and splitting prism, and then reflected 180 degrees after reaching the surface of the beam-combining and splitting prism, and then passes through the inclined surface of the beam-combining and splitting prism to enter the imaging collection unit; the second reflected light first enters the optical path compensation structure, and then passes through the inclined surface of the beam-combining and splitting prism to directly reflect into the imaging collection unit.

[0010] Specifically, the optical path compensation structure is a compensation prism, which is arranged between the second refraction unit and the beam-combining and beam-splitting prism, and is used to compensate for the optical path difference that the second reflected light is reflected one less time in the beam-combining and beam-splitting prism than the first reflected light, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

[0011] Specifically, the optical path compensation structure and the second refraction unit form a first prism group, which is used to compensate for the optical path difference of the second reflected light, which is reflected one less time than the first reflected light in the beam combining and splitting prism, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

[0012] Specifically, the optical path compensation structure and the beam combining and splitting prism form a second prism group, which is used to compensate for the optical path difference of the second reflected light, which is reflected one less time than the first reflected light in the beam combining and splitting prism, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

[0013] Specifically, the image formed by the first light path or the second light path is a Köhler illumination image or a critical illumination image.

[0014] Specifically, it also includes a control unit and a micro-motion platform, the control unit is connected to the imaging collection unit, the micro-motion platform is respectively connected to the reference plates on both sides, the information collected by the imaging collection unit is transmitted to the control unit, and when it is determined that the image is not aligned, the control unit drives the micro-motion platform to move at least one of the first reference plate and the second reference plate to align the first reference plate with the second reference plate.

[0015] Specifically, it also includes two half-glass slides, which are respectively located between the first refraction unit and the beam-combining and splitting prism, and between the second refraction unit and the beam-combining and splitting prism; the half-glass slide converts P light into S light; the beam-combining and splitting prism is a PBS beam-combining and splitting prism, which is used to absorb P light and reflect S light; the half-glass slide and the PBS beam-combining and splitting prism provide a single light for the imaging collection unit.

[0016] Specifically, the first collimating unit includes: a first light source and a first collimating lens; the first refraction unit includes: a first beam splitter prism and a first imaging lens; the second collimating unit includes: a second light source and a first collimating lens; the second refraction unit includes: a second beam splitter prism and a second imaging lens; the imaging collection unit includes: a third imaging lens and a camera; the first imaging sub-lens and the second imaging sub-lens respectively include a magnification compensation element and an image quality compensation element for compensating for the performance difference between the two optical paths.

[0017] Specifically, the third imaging sub-lens includes a magnification compensation element and an image quality compensation element, which are used to compensate for the magnification and aberration of the entire optical system.

[0018] Compared with the prior art, the advantages of the present invention are: by setting a collimating unit and a refraction unit, the light beam illuminates two reference plates, and the optical path from the first reflected light to the imaging system is consistent with the optical path from the second reflected light to the imaging system. By comparing the images, it can be determined whether the two reference plates are aligned; the imaging collection unit collects two patterns at the same time, and there is no response error between the two pattern collections. In addition, the device is not limited by the marking material, the clarity and accuracy of the marking are not affected, and high-precision measurement can be achieved. The alignment device can achieve high-precision alignment between wafers and wafers, and between chips and chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic structural diagram of an alignment device in an embodiment of the present invention;

[0021] Figure 2 is a schematic diagram of an upper light path of an alignment device in an embodiment of the present invention;

[0022] Figure 3 is a schematic diagram of the lower optical path of the alignment device in an embodiment of the present invention;

[0023] Figure 4 Schematic diagram of the structure of an alignment device in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0028] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0029] like Figure 1 As shown, the embodiment of the present application provides an alignment device 100 for directly positioning a first reference plate 101 relative to a second reference plate 103. The alignment device 100 includes: a first collimating unit 10, a second collimating unit 20, a first refraction unit 30, a second refraction unit 40, a beam combining and splitting prism 131, and an imaging collection unit 60.

[0030] The first collimating unit 10 is used to collimate the first light beam. In some embodiments, the first collimating unit 10 may include only the first collimating lens 112, or may include the first light source 111 and the first collimating lens 112, or may include other optical elements for filtering the first light beam and the first collimating lens 112.

[0031] The second collimating unit 20 is used to collimate the second light beam. In some embodiments, the second collimating unit 20 may include only the second collimating lens 122, or may include the second light source 121 and the second collimating lens 122, or may include other optical elements for filtering the second light beam and the second collimating lens 122.

[0032] The first refraction unit 30 is used to irradiate the collimated first light beam to the first reference plate 101. In some embodiments, the first refraction unit 30 includes a first beam splitter prism 113 and a first imaging sub-lens 114.

[0033] The second refraction unit 40 is used to irradiate the collimated second light beam to the second reference plate 103. In some embodiments, the second refraction unit 40 includes a second beam splitter prism 123 and a second imaging sub-lens 124.

[0034] The imaging collection unit 60 is used to collect the reflected light and obtain information therein. In some embodiments, the imaging collection unit 60 includes a third imaging sub-lens 132 and a camera 133 .

[0035] The first collimating unit 10 collimates the first light beam, and the collimated light beam passes through the first refraction unit 30 and then refracts to the first reference plate 101. The first reflected light fed back from the first reference plate 101 passes through the first refraction unit 30, and then passes through the beam combining and splitting prism 131, and irradiates the imaging collection unit 60 to form a first light path; the second collimating unit 20 collimates the second light beam, and the collimated light beam passes through the second refraction unit 40 and then refracts to the second reference plate 103. The second reflected light fed back from the second reference plate 103 passes through the second refraction unit 40, and then passes through the beam combining and splitting prism 131, and irradiates the imaging collection unit 60 to form a second light path.

[0036] The optical path from the first reflected light to the imaging collection unit 60 is consistent with the optical path from the second reflected light to the imaging collection unit 60. In some embodiments, the optical path of the first optical path and the optical path of the second optical path may also be consistent.

[0037] The method of using the above device is as follows:

[0038] (1) The first light beam and the second light beam are irradiated onto the first reference plate 101 and the second reference plate 103 respectively;

[0039] (2) The first reflected light fed back from the first reference plate 101 passes through the beam-combining and beam-splitting prism 131 and is irradiated to the imaging collection unit 60; the first reflected light carries the marking information on the first reference plate 101; the second reflected light fed back from the second reference plate 103 passes through the beam-combining and beam-splitting prism 131 and is irradiated to the imaging collection unit 60; the second reflected light carries the marking information on the second reference plate 103; the optical path from the first reflected light to the imaging collection unit 60 is consistent with the optical path from the second reflected light to the imaging collection unit 60;

[0040] (3) The imaging collection unit 60 generates corresponding images according to the two light beams;

[0041] (4) When the two images overlap, it is determined that the first reference plate 101 and the second reference plate 103 are aligned.

[0042] The above device, by setting a collimating unit and a refraction unit, makes the light beam illuminate the two reference plates, and the optical path from the first reflected light to the imaging system is consistent with the optical path from the second reflected light to the imaging system. By comparing the images, it can be determined whether the two reference plates are aligned; the imaging collection unit collects two patterns at the same time, and there is no response error between the two pattern collections. In addition, the device is not limited by the marking material, the clarity and accuracy of the marking are not affected, and high-precision measurement can be achieved. The alignment device can achieve high-precision alignment between wafers and wafers, and chips and chips.

[0043] In one embodiment, the alignment device further includes an optical path compensation structure. The optical path compensation structure is used to make the first reflected light first reflect 90 degrees when passing through the inclined surface of the beam combining and splitting prism 131, reflect 180 degrees after reaching the surface of the beam combining and splitting prism 131, and then pass through the inclined surface of the beam combining and splitting prism 131 to enter the imaging collection unit 60; the second reflected light first enters the optical path compensation structure, and then passes through the inclined surface of the beam combining and splitting prism 131 to directly reflect and enter the imaging collection unit 60.

[0044] In one embodiment, if Figure 1 As shown, the optical path compensation structure is a compensation prism 125, which is arranged between the second refraction unit 40 and the beam-combining and splitting prism 131, and is used to compensate for the optical path difference of the second reflected light in the beam-combining and splitting prism 131, in which the second reflected light is reflected one less time than the first reflected light, so that the optical path from the first reflected light to the imaging collection unit 60 is consistent with the optical path from the second reflected light to the imaging collection unit 60.

[0045] like Figure 2As shown, the first light source 111 emits a certain amount of light, the first collimating lens 112 converges and collimates the light emitted by the first light source 111, and the collimated light is incident on the first beam splitter prism 113. The first beam splitter prism 113 divides the light from the first light source 111 into two equal parts, one part is incident on the light trap surface through the 45-degree reflection surface and disappears directly, and the other part is reflected by the 45-degree reflection surface and enters the third imaging sub-lens 132 to evenly illuminate the mark in the 102 area.

[0046] In some embodiments, the first collimating lens 112 , the first beam splitter prism 113 , and the first imaging sub-lens 114 form a Kohler illumination system or a critical illumination system for providing illumination to the area 102 .

[0047] The first reflected light passes through the optical path of the imaging system composed of the first imaging sub-lens 114, the first beam splitter prism 113, the beam combining beam splitter prism 131, and the third imaging sub-lens 132. The light beam passes through the 45-degree reflection surface of the beam combining beam splitter prism 131, and then reflects 180 degrees after reaching the surface of the beam combining beam splitter prism 131. The reflected light passes through the 45-degree reflection surface of the beam combining beam splitter prism 131 again and is incident on the third imaging sub-lens 132 until it reaches the imaging system camera 133; at this point, the mark of the first reference plate 101 is imaged on the camera 133.

[0048] like Figure 3 As shown, the second light source 121 emits a certain amount of light, the second collimating lens 122 converges and collimates the light emitted by the second light source 121, and the collimated light is incident on the second beam splitter prism 123. The second beam splitter prism 123 divides the light from the second light source 121 into two parts in equal proportion, one part is incident on the light trap surface through the 45-degree reflection surface and disappears directly, and the other part is reflected by the 45-degree reflection surface and enters the third imaging sub-lens 132 to evenly illuminate the mark in the 104 area.

[0049] In one embodiment, the second collimating lens 122 , the second beam splitter prism 123 and the second imaging sub-lens 124 form a Kohler illumination system or a critical illumination system for providing illumination to the area 104 .

[0050] The second reflected light passes through the imaging system optical path composed of the second imaging sub-lens 124, the second beam splitter prism 123, the compensation prism 125, the beam combining beam splitter prism 131, and the third imaging sub-lens 132. The light beam is reflected by the 45-degree reflection surface of the beam combining beam splitter prism 131 and then incident on the third imaging sub-lens 132 until it reaches the imaging system camera 133; at this point, the mark of the second reference plate 103 is imaged on the camera 133.

[0051] In one embodiment, the optical path compensation structure and the second refraction unit 41 form a first prism group, which is used to compensate for the optical path difference of the second reflected light in the beam combining and splitting prism 131, which is one less reflection than the first reflected light, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

[0052] In one embodiment, the optical path compensation structure and the beam combining and splitting prism 131 form a second prism group, which is used to compensate for the optical path difference of the second reflected light being reflected one less time in the beam combining and splitting prism than the first reflected light, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

[0053] In one embodiment, the first imaging sub-lens 114 and the second imaging sub-lens 124 respectively include a magnification compensation element and an image quality compensation element for compensating for the performance difference between the two optical paths.

[0054] In one embodiment, the third imaging sub-lens 132 includes a magnification compensation element and an image quality compensation element for compensating the magnification and aberration of the entire optical system.

[0055] The first collimating lens 112 and the second collimating lens 122 respectively converge and collimate the light emitted by the first light source 111 and the second light source 121, and the collimated light is incident on the first beam splitter prism 113 and the second beam splitter prism 123 respectively, and the first beam splitter prism 113 and the second beam splitter prism 123 respectively reflect different lights to the first reference plate 101 and the second reference plate 103; the first imaging lens 114 and the second imaging lens 124 detect the reference points on the first reference plate 101 and the second reference plate 103, the first reflected light is first reflected 90 degrees through the 45-degree reflecting surface of the beam combining beam splitter prism 131, and then reflected 180 degrees after reaching the surface of the beam combining beam splitter prism 131, and the reflected light is again incident on the third imaging sub-lens 132 through the 45-degree reflecting surface of the beam combining beam splitter prism 131, until it reaches the imaging system camera 133. The second reflected light passes through the imaging system optical path composed of the second imaging sub-lens 124, the second beam splitter prism 123, the compensation prism 125, the beam combining beam splitter prism 131, and the third imaging sub-lens 132. The light beam is reflected by the 45-degree reflection surface of the beam combining beam splitter prism 131 and then enters the third imaging sub-lens 132 until the imaging system camera 133, and the camera 133 compares the image information. When it is determined that the two reference plates are aligned, the bonding operation is performed; when it is determined that the two reference plates are not aligned, the control unit 150 calculates the position deviation of the first reference plate 101 and the second reference plate 103 through a specific algorithm, and feeds it back to the micro-motion platform. The micro-motion platform includes a precision motion stage 105 and a precision motion stage 106 with five-degree-of-freedom motion capability. The control unit 150 controls the movement of the precision motion stage 105 and the precision motion stage 106 to achieve high-precision compensation of the horizontal offset and the rotation angle, and eliminates the horizontal error caused by the vertical movement and the horizontal position system deviation caused by the non-perpendicularity between the optical axis of the alignment system and the substrate surface during measurement. The precision motion stage 105 is connected to the first reference plate 101, and the precision motion stage 106 is connected to the second reference plate 103. The control unit 150 drives the micro-motion platform to move at least one of the first reference plate 101 and the second reference plate 103, so that the first reference plate 101 and the second reference plate 103 are aligned. After the movement is completed, the alignment judgment is performed again, and after it is judged that the two reference plates are aligned, the bonding operation is performed.

[0056] like Figure 4 As shown, an embodiment provides an alignment device 600 including: a first collimating unit 11 , a second collimating unit 21 , a first refraction unit 31 , a second refraction unit 41 , a beam combining and splitting prism 131 , and an imaging collection unit 61 .

[0057] The first collimating unit 11 is used to collimate the first light beam. In some embodiments, the first collimating unit 11 may include only the first collimating lens 112, or may include the first light source 111 and the first collimating lens 112, or may include other optical elements for filtering the first light beam and the first collimating lens 112.

[0058] The second collimating unit 21 is used to collimate the second light beam. In some embodiments, the second collimating unit 21 may include only the second collimating lens 122, or may include the second light source 121 and the second collimating lens 122, or may include other optical elements for filtering the second light beam and the second collimating lens 122.

[0059] The first refraction unit 31 is used to irradiate the collimated first light beam to the first reference plate. In some embodiments, the first refraction unit 31 includes a first beam splitter prism 113 , a first imaging sub-lens 114 and a first half glass slide 115 .

[0060] The second refraction unit 41 is used to irradiate the collimated second light beam to the second reference plate. In some embodiments, the second refraction unit 40 includes a second beam splitter prism 123 , a second imaging sub-lens 124 and a second half glass slide 125 .

[0061] The imaging collection unit 61 is used to collect reflected light and obtain information therein. In some embodiments, the imaging collection unit 60 includes a third imaging sub-lens 132 and a camera 133 .

[0062] The beam combining and splitting prism 131 is a PBS beam combining and splitting prism.

[0063] The first light source 111 emits a certain amount of light, and the first collimating lens 112 converges and collimates the light emitted by the first light source 111. The collimated light is incident on the first PBS beam splitter prism 113. The first PBS beam splitter prism 113 splits the light from the first light source 111 into two parts, P light and S light. The P light passes through the PBS beam splitter surface and is incident on the light trap surface and disappears directly. The S light is reflected by the first PBS beam splitter surface and enters the first imaging sub-lens 114 to evenly illuminate the mark in the 102 area.

[0064] The first reflected light passes through the optical path of the imaging system composed of the first imaging sub-lens 114, the first PBS beam splitter prism 113, the first half glass slide 115, the PBS beam combining beam splitter prism 131, and the third imaging sub-lens 132. The P light passes through the half glass slide 115 to become the S light, and the S light passes through the beam splitting surface of the PBS beam combining beam splitter prism 131, and then reflects 180 degrees after reaching the prism surface. At this time, the polarization state is the P light, and the P light passes through the beam splitting surface of the PBS beam combining beam splitter prism 131 again to be incident on the third imaging sub-lens 132, and then to the camera 133; at this point, the mark on the first reference plate 101 is imaged on the camera 133.

[0065] The second light source 121 emits a certain amount of light, and the second collimating lens 122 converges and collimates the light emitted by the second light source 121. The collimated light is incident on the second PBS beam splitter prism 123. The second PBS beam splitter prism 123 splits the light from the second light source 121 into two parts, P light and S light. The P light passes through the PBS beam splitter surface and is incident on the light trap surface and disappears directly. The S light is reflected by the second PBS beam splitter surface and enters the second imaging sub-lens 124 to evenly illuminate the mark in area 104.

[0066] The second reflected light passes through the optical path of the imaging system composed of the second imaging sub-lens 124, the second PBS beam splitter prism 123, the second half glass slide 125, the compensation prism 126, the PBS beam combining beam splitter prism 131, and the third imaging sub-lens 132. The P light passes through the half glass slide 125 to become the S light, and the S light passes through the beam splitting surface of the PBS beam combining beam splitter prism 131 and is first reflected by 90 degrees. At this time, the polarization state is S light, and the S light is incident on the third imaging sub-lens 132 again until it reaches the camera 133; at this point, the mark on the second reference plate 103 is imaged on the camera 133.

[0067] The first light source 111 and the second light source 121 emit a certain amount of light, the first collimating lens 112 and the second collimating lens 122 respectively converge and collimate the light emitted by the first light source 111 and the second light source 121, and the collimated light is respectively incident on the first PBS beam splitter prism 113 and the second PBS beam splitter prism 123, the first PBS beam splitter prism 113 and the second PBS beam splitter prism 123 respectively split the light from the first light source 111 and the second light source 121 into two parts, P light and S light, the P light passes through the PBS beam splitter surface and is incident on the light trap surface and disappears directly, the S light is reflected by the first PBS beam splitter surface and enters the first imaging sub-lens 114 and the second imaging sub-lens 124 respectively to evenly irradiate the first reference plate 101 and the second reference plate 103. The first reflected light passes through the first imaging sub-lens 114, and then is reflected by the first PBS beam splitter prism 113. The P light passes through the first half glass 115 to become the S light. The S light passes through the beam splitting surface of the PBS beam combining and beam splitting prism 131, and then reflects 180 degrees after reaching the prism surface. At this time, the polarization state is P light. The P light passes through the beam splitting surface of the PBS beam combining and beam splitting prism 131 again and is incident on the third imaging sub-lens 132 until it reaches the camera 133. The second reflected light passes through one more compensation prism 126 than the first reflected light. The camera 133 compares the image information. When it is determined that the two reference plates are aligned, the bonding operation is performed; when it is determined that the two reference plates are not aligned, the control unit 150 calculates the position deviation of the first reference plate 101 and the second reference plate 103 through a specific algorithm, the precision motion stage 105 is connected to the first reference plate 101, and the precision motion stage 106 is connected to the second reference plate 103, and the control unit 150 drives the micro-motion platform to move at least one of the first reference plate 101 and the second reference plate 103, so that the first reference plate 101 and the second reference plate 103 are aligned. After the movement is completed, the alignment judgment is performed again, and after it is determined that the two reference plates are aligned, the bonding operation is performed.

[0068] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. An alignment device for directly positioning a first reference plate relative to a second reference plate, characterized in that: include: A first collimating unit, a first refractive unit, a second collimating unit, a second refractive unit, a beam combining and splitting prism, and an imaging collection unit; The first collimating unit collimates the first light beam, and refracts the first light beam to the first reference plate after passing through the first refraction unit. The first reflected light fed back from the first reference plate passes through the beam combining and splitting prism, and irradiates the imaging collection unit to form a first light path. The second collimating unit collimates the second light beam, and refracts the second light beam to the second reference plate after passing through the second refraction unit. The second reflected light fed back from the second reference plate passes through the beam combining and splitting prism, and irradiates the imaging collection unit to form a second light path. The optical path from the first reflected light to the imaging collection unit is consistent with the optical path from the second reflected light to the imaging collection unit.

2. The alignment device according to claim 1, characterized in that It also includes an optical path compensation structure, wherein the first reflected light is first reflected at 90 degrees when passing through the inclined surface of the beam-combining and beam-splitting prism, and then reflected at 180 degrees after reaching the surface of the beam-splitting prism, and then passes through the inclined surface of the beam-combining and beam-splitting prism to enter the imaging collection unit; the second reflected light first enters the optical path compensation structure, and then passes through the inclined surface of the beam-combining and beam-splitting prism to directly reflect into the imaging collection unit.

3. The alignment device according to claim 2, characterized in that: The optical path compensation structure is a compensation prism, which is arranged between the second refraction unit and the beam-combining and beam-splitting prism, and is used to compensate for the optical path difference that the second reflected light is reflected one less time in the beam-combining and beam-splitting prism than the first reflected light, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

4. The alignment device according to claim 2, characterized in that: The optical path compensation structure and the second refraction unit form a first prism group, which is used to compensate for the optical path difference of the second reflected light, which is reflected one less time than the first reflected light in the beam combining and splitting prism, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

5. The alignment device according to claim 2, characterized in that: The optical path compensation structure and the beam combining and splitting prism form a second prism group, which is used to compensate for the optical path difference of the second reflected light, which is reflected one less time than the first reflected light in the beam combining and splitting prism, so that the optical path of the first reflected light to the imaging system is consistent with the optical path of the second reflected light to the imaging system.

6. The alignment device according to claim 1, characterized in that: The image formed by the first light path or the second light path is a Kohler illumination image or a critical illumination image.

7. The alignment device according to claim 1, characterized in that: It also includes a control unit and a micro-motion platform, the control unit is connected to the imaging collection unit, the micro-motion platform is respectively connected to the reference plates on both sides, the information collected by the imaging collection unit is transmitted to the control unit, and when it is determined that the image is not aligned, the control unit drives the micro-motion platform to move at least one of the first reference plate and the second reference plate to align the first reference plate with the second reference plate.

8. The alignment device according to claim 1, characterized in that It also includes two half-glass slides, which are respectively located between the first refraction unit and the beam-combining and splitting prism, and between the second refraction unit and the beam-combining and splitting prism; the half-glass slide converts P light into S light; the beam-combining and splitting prism is a PBS beam-combining and splitting prism, which is used to absorb P light and reflect S light; the half-glass slide and the PBS beam-combining and splitting prism provide a single light for the imaging collection unit.

9. The alignment device according to claim 1, characterized in that: The first collimating unit includes: a first light source and a first collimating lens; the first refraction unit includes: a first beam splitter prism and a first imaging lens; the second collimating unit includes: a second light source and a first collimating lens; the second refraction unit includes: a second beam splitter prism and a second imaging lens; the imaging collection unit includes: a third imaging lens and a camera; the first imaging sub-lens and the second imaging sub-lens respectively include a magnification compensation element and an image quality compensation element, which are used to compensate for the performance difference between the two optical paths.

10. The alignment device according to claim 9, characterized in that The third imaging sub-lens includes a magnification compensation element and an image quality compensation element, which are used to compensate for the magnification and aberration of the entire optical system.

11. The alignment method of an alignment device according to any one of claims 1 to 10, characterized in that: The following steps are involved: (1) The first light beam and the second light beam are irradiated onto the first reference plate and the second reference plate respectively; (2) The first reflected light fed back from the first reference plate passes through a beam combining and splitting prism and irradiates an imaging collection unit; the second reflected light fed back from the second reference plate passes through a beam combining and splitting prism and irradiates an imaging collection unit; the optical path from the first reflected light to the imaging collection unit is the same as the optical path from the second reflected light to the imaging collection unit; (3) The imaging collection unit generates corresponding images according to the two light beams; (4) When the two images overlap, it is determined that the first reference plate and the second reference plate are aligned.

Images